diff --git a/src/share/vm/jfr/dcmd/jfrDcmds.cpp b/src/share/vm/jfr/dcmd/jfrDcmds.cpp
index 77687e84bed84fe650c9b5153d565c9573e43df8..e0c11da18bc2e522264e45b0b25d448f1709bcdd 100644
--- a/src/share/vm/jfr/dcmd/jfrDcmds.cpp
+++ b/src/share/vm/jfr/dcmd/jfrDcmds.cpp
@@ -345,6 +345,7 @@ JfrStartFlightRecordingDCmd::JfrStartFlightRecordingDCmd(outputStream* output,
   _disk("disk", "Recording should be persisted to disk", "BOOLEAN", false),
   _maxage("maxage", "Maximum time to keep recorded data (on disk) in (s)econds, (m)inutes, (h)ours, or (d)ays, e.g. 60m, or 0 for no limit", "NANOTIME", false, "0"),
   _maxsize("maxsize", "Maximum amount of bytes to keep (on disk) in (k)B, (M)B or (G)B, e.g. 500M, or 0 for no limit", "MEMORY SIZE", false, "0"),
+  _flush_interval("flush-interval", "Minimum time before flushing buffers, measured in (s)econds, e.g. 4 s, or 0 for flushing when a recording ends", "NANOTIME", false, "1s"),
   _dump_on_exit("dumponexit", "Dump running recording when JVM shuts down", "BOOLEAN", false),
   _path_to_gc_roots("path-to-gc-roots", "Collect path to GC roots", "BOOLEAN", false, "false") {
   _dcmdparser.add_dcmd_option(&_name);
@@ -355,6 +356,7 @@ JfrStartFlightRecordingDCmd::JfrStartFlightRecordingDCmd(outputStream* output,
   _dcmdparser.add_dcmd_option(&_filename);
   _dcmdparser.add_dcmd_option(&_maxage);
   _dcmdparser.add_dcmd_option(&_maxsize);
+  _dcmdparser.add_dcmd_option(&_flush_interval);
   _dcmdparser.add_dcmd_option(&_dump_on_exit);
   _dcmdparser.add_dcmd_option(&_path_to_gc_roots);
 };
@@ -407,6 +409,10 @@ void JfrStartFlightRecordingDCmd::execute(DCmdSource source, TRAPS) {
     maxsize = JfrJavaSupport::new_java_lang_Long(_maxsize.value()._size, CHECK);
   }
 
+  jobject flush_interval = NULL;
+  if (_flush_interval.is_set()) {
+    flush_interval = JfrJavaSupport::new_java_lang_Long(_flush_interval.value()._nanotime, CHECK);
+  }
   jobject duration = NULL;
   if (_duration.is_set()) {
     duration = JfrJavaSupport::new_java_lang_Long(_duration.value()._nanotime, CHECK);
@@ -460,7 +466,7 @@ void JfrStartFlightRecordingDCmd::execute(DCmdSource source, TRAPS) {
   static const char method[] = "execute";
   static const char signature[] = "(Ljava/lang/String;[Ljava/lang/String;Ljava/lang/Long;"
     "Ljava/lang/Long;Ljava/lang/Boolean;Ljava/lang/String;"
-    "Ljava/lang/Long;Ljava/lang/Long;Ljava/lang/Boolean;Ljava/lang/Boolean;)Ljava/lang/String;";
+    "Ljava/lang/Long;Ljava/lang/Long;Ljava/lang/Long;Ljava/lang/Boolean;Ljava/lang/Boolean;)Ljava/lang/String;";
 
   JfrJavaArguments execute_args(&result, klass, method, signature, CHECK);
   execute_args.set_receiver(h_dcmd_instance);
@@ -474,6 +480,7 @@ void JfrStartFlightRecordingDCmd::execute(DCmdSource source, TRAPS) {
   execute_args.push_jobject(filename);
   execute_args.push_jobject(maxage);
   execute_args.push_jobject(maxsize);
+  execute_args.push_jobject(flush_interval);
   execute_args.push_jobject(dump_on_exit);
   execute_args.push_jobject(path_to_gc_roots);
 
diff --git a/src/share/vm/jfr/dcmd/jfrDcmds.hpp b/src/share/vm/jfr/dcmd/jfrDcmds.hpp
index 425a07875e136b3a09a5e064d4541e0572923ec2..953a9f60d38f734e3c1f2ed6906460d3025c2741 100644
--- a/src/share/vm/jfr/dcmd/jfrDcmds.hpp
+++ b/src/share/vm/jfr/dcmd/jfrDcmds.hpp
@@ -90,6 +90,7 @@ class JfrStartFlightRecordingDCmd : public DCmdWithParser {
   DCmdArgument<char*> _filename;
   DCmdArgument<NanoTimeArgument> _maxage;
   DCmdArgument<MemorySizeArgument> _maxsize;
+  DCmdArgument<NanoTimeArgument> _flush_interval;
   DCmdArgument<bool> _dump_on_exit;
   DCmdArgument<bool> _path_to_gc_roots;
 
diff --git a/src/share/vm/jfr/jfr.cpp b/src/share/vm/jfr/jfr.cpp
index 06d3b79837e86ca737ae477a43c9b111aa6135be..b5905d1e688234b371b959bbce16809eeaf5e8a8 100644
--- a/src/share/vm/jfr/jfr.cpp
+++ b/src/share/vm/jfr/jfr.cpp
@@ -78,6 +78,18 @@ void Jfr::on_thread_exit(Thread* t) {
   JfrThreadLocal::on_exit(t);
 }
 
+void Jfr::exclude_thread(Thread* t) {
+  JfrThreadLocal::exclude(t);
+}
+
+void Jfr::include_thread(Thread* t) {
+  JfrThreadLocal::include(t);
+}
+
+bool Jfr::is_excluded(Thread* t) {
+  return t != NULL && t->jfr_thread_local()->is_excluded();
+}
+
 void Jfr::on_java_thread_dismantle(JavaThread* jt) {
   if (JfrRecorder::is_recording()) {
     JfrCheckpointManager::write_thread_checkpoint(jt);
diff --git a/src/share/vm/jfr/jfr.hpp b/src/share/vm/jfr/jfr.hpp
index a09d7ef7c6c17d75d2838bc39a5d8534b47c4de2..04e0cfb6518617256a0672247e09c71f7eae64f6 100644
--- a/src/share/vm/jfr/jfr.hpp
+++ b/src/share/vm/jfr/jfr.hpp
@@ -56,6 +56,9 @@ class Jfr : AllStatic {
   static void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f);
   static void weak_oops_do(OopClosure* f);
   static Thread* sampler_thread();
+  static void exclude_thread(Thread* thread);
+  static bool is_excluded(Thread* thread);
+  static void include_thread(Thread* thread);
 };
 
 #endif // SHARE_VM_JFR_JFR_HPP
diff --git a/src/share/vm/jfr/jni/jfrJavaSupport.cpp b/src/share/vm/jfr/jni/jfrJavaSupport.cpp
index f3232b56ff5e05cd64929bc2898e3e193c552b50..db7511c5f02e0edc28213be007778845fde774d1 100644
--- a/src/share/vm/jfr/jni/jfrJavaSupport.cpp
+++ b/src/share/vm/jfr/jni/jfrJavaSupport.cpp
@@ -23,7 +23,6 @@
  */
 
 #include "precompiled.hpp"
-#include "jni.h"
 #include "classfile/javaClasses.hpp"
 #include "classfile/symbolTable.hpp"
 #include "classfile/systemDictionary.hpp"
@@ -40,9 +39,11 @@
 #include "runtime/fieldDescriptor.hpp"
 #include "runtime/java.hpp"
 #include "runtime/jniHandles.hpp"
+#include "runtime/semaphore.inline.hpp"
 #include "runtime/synchronizer.hpp"
 #include "runtime/thread.inline.hpp"
 //#include "runtime/threadSMR.hpp"
+#include "utilities/growableArray.hpp"
 
 #ifdef ASSERT
 void JfrJavaSupport::check_java_thread_in_vm(Thread* t) {
@@ -56,6 +57,14 @@ void JfrJavaSupport::check_java_thread_in_native(Thread* t) {
   assert(t->is_Java_thread(), "invariant");
   assert(((JavaThread*)t)->thread_state() == _thread_in_native, "invariant");
 }
+
+static void check_new_unstarted_java_thread(Thread* t) {
+  assert(t != NULL, "invariant");
+  assert(t->is_Java_thread(), "invariant");
+  // The start-up process of JFR is different from that of upstream,
+  // so the following line needs to be commented out
+  // assert(((JavaThread*)t)->thread_state() == _thread_new, "invariant");
+}
 #endif
 
 /*
@@ -91,6 +100,21 @@ void JfrJavaSupport::destroy_global_jni_handle(const jobject handle) {
   JNIHandles::destroy_global(handle);
 }
 
+jweak JfrJavaSupport::global_weak_jni_handle(const oop obj, Thread* t) {
+  DEBUG_ONLY(check_java_thread_in_vm(t));
+  HandleMark hm(t);
+  return JNIHandles::make_weak_global(Handle(t, obj));
+}
+
+jweak JfrJavaSupport::global_weak_jni_handle(const jobject handle, Thread* t) {
+  const oop obj = JNIHandles::resolve(handle);
+  return obj == NULL ? NULL : global_weak_jni_handle(obj, t);
+}
+
+void JfrJavaSupport::destroy_global_weak_jni_handle(jweak handle) {
+  JNIHandles::destroy_weak_global(handle);
+}
+
 oop JfrJavaSupport::resolve_non_null(jobject obj) {
   return JNIHandles::resolve_non_null(obj);
 }
@@ -574,14 +598,141 @@ JfrJavaSupport::CAUSE JfrJavaSupport::cause() {
   return _cause;
 }
 
-// XXX
-//const char* const JDK_JFR_MODULE_NAME = "jdk.jfr";
-//const char* const JDK_JFR_PACKAGE_NAME = "jdk/jfr";
+class ThreadExclusionListAccess : public StackObj {
+ private:
+  static Semaphore _mutex_semaphore;
+ public:
+  ThreadExclusionListAccess() { _mutex_semaphore.wait(); }
+  ~ThreadExclusionListAccess() { _mutex_semaphore.signal(); }
+};
+
+Semaphore ThreadExclusionListAccess::_mutex_semaphore(1);
+static GrowableArray<jweak>* exclusion_list = NULL;
+
+static bool equals(const jweak excluded_thread, Handle target_thread) {
+  return JfrJavaSupport::resolve_non_null(excluded_thread) == target_thread();
+}
+
+static int find_exclusion_thread_idx(Handle thread) {
+  if (exclusion_list != NULL) {
+    for (int i = 0; i < exclusion_list->length(); ++i) {
+      if (equals(exclusion_list->at(i), thread)) {
+        return i;
+      }
+    }
+  }
+  return -1;
+}
+
+static Handle as_handle(jobject thread) {
+  return Handle(Thread::current(), JfrJavaSupport::resolve_non_null(thread));
+}
+
+static bool thread_is_not_excluded(Handle thread) {
+  return -1 == find_exclusion_thread_idx(thread);
+}
+
+static bool thread_is_not_excluded(jobject thread) {
+  return thread_is_not_excluded(as_handle(thread));
+}
+
+static bool is_thread_excluded(jobject thread) {
+  return !thread_is_not_excluded(thread);
+}
+
+#ifdef ASSERT
+static bool is_thread_excluded(Handle thread) {
+  return !thread_is_not_excluded(thread);
+}
+#endif // ASSERT
+
+static int add_thread_to_exclusion_list(jobject thread) {
+  ThreadExclusionListAccess lock;
+  if (exclusion_list == NULL) {
+    exclusion_list = new (ResourceObj::C_HEAP, mtTracing) GrowableArray<jweak>(10, true, mtTracing);
+  }
+  assert(exclusion_list != NULL, "invariant");
+  assert(thread_is_not_excluded(thread), "invariant");
+  jweak ref = JfrJavaSupport::global_weak_jni_handle(thread, Thread::current());
+  const int idx = exclusion_list->append(ref);
+  assert(is_thread_excluded(thread), "invariant");
+  return idx;
+}
+
+static void remove_thread_from_exclusion_list(Handle thread) {
+  assert(exclusion_list != NULL, "invariant");
+  assert(is_thread_excluded(thread), "invariant");
+  assert(exclusion_list != NULL, "invariant");
+  const int idx = find_exclusion_thread_idx(thread);
+  assert(idx >= 0, "invariant");
+  assert(idx < exclusion_list->length(), "invariant");
+  JfrJavaSupport::destroy_global_weak_jni_handle(exclusion_list->at(idx));
+  exclusion_list->delete_at(idx);
+  assert(thread_is_not_excluded(thread), "invariant");
+  if (0 == exclusion_list->length()) {
+    delete exclusion_list;
+    exclusion_list = NULL;
+  }
+}
+
+static void remove_thread_from_exclusion_list(jobject thread) {
+  ThreadExclusionListAccess lock;
+  remove_thread_from_exclusion_list(as_handle(thread));
+}
 
-jlong JfrJavaSupport::jfr_thread_id(jobject target_thread) {
-//  ThreadsListHandle tlh;
-  // XXX is it correct and safe?
-  JavaThread* native_thread = java_lang_Thread::thread(JNIHandles::resolve_non_null(target_thread));
-//  (void)tlh.cv_internal_thread_to_JavaThread(target_thread, &native_thread, NULL);
+// includes removal
+static bool check_exclusion_state_on_thread_start(JavaThread* jt) {
+  Handle h_obj(jt, jt->threadObj());
+  ThreadExclusionListAccess lock;
+  if (thread_is_not_excluded(h_obj)) {
+    return false;
+  }
+  remove_thread_from_exclusion_list(h_obj);
+  return true;
+}
+
+jlong JfrJavaSupport::jfr_thread_id(jobject thread) {
+  JavaThread* native_thread = java_lang_Thread::thread(JNIHandles::resolve_non_null(thread));
   return native_thread != NULL ? JFR_THREAD_ID(native_thread) : 0;
 }
+
+void JfrJavaSupport::exclude(jobject thread) {
+  HandleMark hm;
+  JavaThread* native_thread = java_lang_Thread::thread(JNIHandles::resolve_non_null(thread));
+  if (native_thread != NULL) {
+    JfrThreadLocal::exclude(native_thread);
+  } else {
+    // not started yet, track the thread oop
+    add_thread_to_exclusion_list(thread);
+  }
+}
+
+void JfrJavaSupport::include(jobject thread) {
+  HandleMark hm;
+  JavaThread* native_thread = java_lang_Thread::thread(JNIHandles::resolve_non_null(thread));
+  if (native_thread != NULL) {
+    JfrThreadLocal::include(native_thread);
+  } else {
+    // not started yet, untrack the thread oop
+    remove_thread_from_exclusion_list(thread);
+  }
+}
+
+bool JfrJavaSupport::is_excluded(jobject thread) {
+  HandleMark hm;
+  JavaThread* native_thread = java_lang_Thread::thread(JNIHandles::resolve_non_null(thread));
+  return native_thread != NULL ? native_thread->jfr_thread_local()->is_excluded() : is_thread_excluded(thread);
+}
+
+void JfrJavaSupport::on_thread_start(Thread* t) {
+  assert(t != NULL, "invariant");
+  assert(Thread::current() == t, "invariant");
+  if (!t->is_Java_thread()) {
+    return;
+  }
+  DEBUG_ONLY(check_new_unstarted_java_thread(t);)
+  HandleMark hm;
+  if (check_exclusion_state_on_thread_start((JavaThread*)t)) {
+    JfrThreadLocal::exclude(t);
+  }
+}
diff --git a/src/share/vm/jfr/jni/jfrJavaSupport.hpp b/src/share/vm/jfr/jni/jfrJavaSupport.hpp
index d08c4b96e1b1a219c3e939fd2f40b333cebf1603..c837ec386ada5fb0afb8a4a0696984b0c58fafd7 100644
--- a/src/share/vm/jfr/jni/jfrJavaSupport.hpp
+++ b/src/share/vm/jfr/jni/jfrJavaSupport.hpp
@@ -29,18 +29,21 @@
 #include "utilities/exceptions.hpp"
 
 class Klass;
-class JavaThread;
 class outputStream;
 
 class JfrJavaSupport : public AllStatic {
  public:
   static jobject local_jni_handle(const oop obj, Thread* t);
   static jobject local_jni_handle(const jobject handle, Thread* t);
-  static void destroy_local_jni_handle(const jobject handle);
+  static void destroy_local_jni_handle(jobject handle);
 
   static jobject global_jni_handle(const oop obj, Thread* t);
   static jobject global_jni_handle(const jobject handle, Thread* t);
-  static void destroy_global_jni_handle(const jobject handle);
+  static void destroy_global_jni_handle(jobject handle);
+
+  static jweak global_weak_jni_handle(const oop obj, Thread* t);
+  static jweak global_weak_jni_handle(const jobject handle, Thread* t);
+  static void destroy_global_weak_jni_handle(jweak handle);
 
   static oop resolve_non_null(jobject obj);
   static void notify_all(jobject obj, TRAPS);
@@ -83,7 +86,11 @@ class JfrJavaSupport : public AllStatic {
   static void throw_class_format_error(const char* message, TRAPS);
   static void throw_runtime_exception(const char* message, TRAPS);
 
-  static jlong jfr_thread_id(jobject target_thread);
+  static jlong jfr_thread_id(jobject thread);
+  static void exclude(jobject thread);
+  static void include(jobject thread);
+  static bool is_excluded(jobject thread);
+  static void on_thread_start(Thread* t);
 
   // critical
   static void abort(jstring errorMsg, TRAPS);
diff --git a/src/share/vm/jfr/jni/jfrJniMethod.cpp b/src/share/vm/jfr/jni/jfrJniMethod.cpp
index c02271b6525a39b47d573ccff1c525bcea71ce02..30e5f5d590bce9af461ba9cb47fd935dfe222489 100644
--- a/src/share/vm/jfr/jni/jfrJniMethod.cpp
+++ b/src/share/vm/jfr/jni/jfrJniMethod.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -303,6 +303,10 @@ JVM_ENTRY_NO_ENV(jboolean, jfr_event_writer_flush(JNIEnv* env, jclass cls, jobje
   return JfrJavaEventWriter::flush(writer, used_size, requested_size, thread);
 JVM_END
 
+JVM_ENTRY_NO_ENV(void, jfr_flush(JNIEnv* env, jobject jvm))
+  JfrRepository::flush(thread);
+JVM_END
+
 JVM_ENTRY_NO_ENV(void, jfr_set_repository_location(JNIEnv* env, jobject repo, jstring location))
   return JfrRepository::set_path(location, thread);
 JVM_END
@@ -330,3 +334,20 @@ JVM_END
 JVM_ENTRY_NO_ENV(void, jfr_emit_old_object_samples(JNIEnv* env, jobject jvm, jlong cutoff_ticks, jboolean emit_all))
   LeakProfiler::emit_events(cutoff_ticks, emit_all == JNI_TRUE);
 JVM_END
+
+JVM_ENTRY_NO_ENV(void, jfr_exclude_thread(JNIEnv* env, jobject jvm, jobject t))
+  JfrJavaSupport::exclude(t);
+JVM_END
+
+JVM_ENTRY_NO_ENV(void, jfr_include_thread(JNIEnv* env, jobject jvm, jobject t))
+  JfrJavaSupport::include(t);
+JVM_END
+
+JVM_ENTRY_NO_ENV(jboolean, jfr_is_thread_excluded(JNIEnv* env, jobject jvm, jobject t))
+  return JfrJavaSupport::is_excluded(t);
+JVM_END
+
+JVM_ENTRY_NO_ENV(jlong, jfr_chunk_start_nanos(JNIEnv* env, jobject jvm))
+  return JfrRepository::current_chunk_start_nanos();
+JVM_END
+
diff --git a/src/share/vm/jfr/jni/jfrJniMethod.hpp b/src/share/vm/jfr/jni/jfrJniMethod.hpp
index 4a9a3eb5f582dce7a91457e9f01db9116160d448..a9a56ee2c8cff2854dff6ad1ab6dc923e220efc0 100644
--- a/src/share/vm/jfr/jni/jfrJniMethod.hpp
+++ b/src/share/vm/jfr/jni/jfrJniMethod.hpp
@@ -117,6 +117,7 @@ jobject JNICALL jfr_new_event_writer(JNIEnv* env, jclass cls);
 
 jboolean JNICALL jfr_event_writer_flush(JNIEnv* env, jclass cls, jobject writer, jint used_size, jint requested_size);
 
+void JNICALL jfr_flush(JNIEnv* env, jobject jvm);
 void JNICALL jfr_abort(JNIEnv* env, jobject jvm, jstring errorMsg);
 
 jlong JNICALL jfr_get_epoch_address(JNIEnv* env, jobject jvm);
@@ -135,6 +136,13 @@ void JNICALL jfr_emit_old_object_samples(JNIEnv* env, jobject jvm, jlong cutoff_
 
 jboolean JNICALL jfr_should_rotate_disk(JNIEnv* env, jobject jvm);
 
+void JNICALL jfr_exclude_thread(JNIEnv* env, jobject jvm, jobject t);
+
+void JNICALL jfr_include_thread(JNIEnv* env, jobject jvm, jobject t);
+
+jboolean JNICALL jfr_is_thread_excluded(JNIEnv* env, jobject jvm, jobject t);
+
+jlong JNICALL jfr_chunk_start_nanos(JNIEnv* env, jobject jvm);
 
 #ifdef __cplusplus
 }
diff --git a/src/share/vm/jfr/jni/jfrJniMethodRegistration.cpp b/src/share/vm/jfr/jni/jfrJniMethodRegistration.cpp
index cedb941a1fa0f0057ec14f0f6a4016dd4cb61d18..e8ce2480c0b42c6dc75319db20a08329d40b5954 100644
--- a/src/share/vm/jfr/jni/jfrJniMethodRegistration.cpp
+++ b/src/share/vm/jfr/jni/jfrJniMethodRegistration.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -72,6 +72,7 @@ JfrJniMethodRegistration::JfrJniMethodRegistration(JNIEnv* env) {
       (char*)"getEventWriter", (char*)"()Ljava/lang/Object;", (void*)jfr_get_event_writer,
       (char*)"newEventWriter", (char*)"()Ljdk/jfr/internal/EventWriter;", (void*)jfr_new_event_writer,
       (char*)"flush", (char*)"(Ljdk/jfr/internal/EventWriter;II)Z", (void*)jfr_event_writer_flush,
+      (char*)"flush", (char*)"()V", (void*)jfr_flush,
       (char*)"setRepositoryLocation", (char*)"(Ljava/lang/String;)V", (void*)jfr_set_repository_location,
       (char*)"abort", (char*)"(Ljava/lang/String;)V", (void*)jfr_abort,
       (char*)"getEpochAddress", (char*)"()J",(void*)jfr_get_epoch_address,
@@ -81,7 +82,11 @@ JfrJniMethodRegistration::JfrJniMethodRegistration(JNIEnv* env) {
       (char*)"getUnloadedEventClassCount", (char*)"()J", (void*)jfr_get_unloaded_event_classes_count,
       (char*)"setCutoff", (char*)"(JJ)Z", (void*)jfr_set_cutoff,
       (char*)"emitOldObjectSamples", (char*)"(JZ)V", (void*)jfr_emit_old_object_samples,
-      (char*)"shouldRotateDisk", (char*)"()Z", (void*)jfr_should_rotate_disk
+      (char*)"shouldRotateDisk", (char*)"()Z", (void*)jfr_should_rotate_disk,
+      (char*)"exclude", (char*)"(Ljava/lang/Thread;)V", (void*)jfr_exclude_thread,
+      (char*)"include", (char*)"(Ljava/lang/Thread;)V", (void*)jfr_include_thread,
+      (char*)"isExcluded", (char*)"(Ljava/lang/Thread;)Z", (void*)jfr_is_thread_excluded,
+      (char*)"getChunkStartNanos", (char*)"()J", (void*)jfr_chunk_start_nanos
     };
 
     const size_t method_array_length = sizeof(method) / sizeof(JNINativeMethod);
diff --git a/src/share/vm/jfr/leakprofiler/chains/edgeStore.cpp b/src/share/vm/jfr/leakprofiler/chains/edgeStore.cpp
index ad549f4864a77f25b65b389241b726c4b1a24b2d..67854ef3fa5fab0d7926df0380984517b681e1f9 100644
--- a/src/share/vm/jfr/leakprofiler/chains/edgeStore.cpp
+++ b/src/share/vm/jfr/leakprofiler/chains/edgeStore.cpp
@@ -259,6 +259,7 @@ void EdgeStore::put_chain(const Edge* chain, size_t length) {
   assert(leak_context_edge->parent() == NULL, "invariant");
 
   if (1 == length) {
+    store_gc_root_id_in_leak_context_edge(leak_context_edge, leak_context_edge);
     return;
   }
 
diff --git a/src/share/vm/jfr/leakprofiler/checkpoint/eventEmitter.cpp b/src/share/vm/jfr/leakprofiler/checkpoint/eventEmitter.cpp
index ff58db7dd4b8501d5029657ac128bdc40a649efb..6a6bc87c4352fc94a0525b2dbeb436ac309e852a 100644
--- a/src/share/vm/jfr/leakprofiler/checkpoint/eventEmitter.cpp
+++ b/src/share/vm/jfr/leakprofiler/checkpoint/eventEmitter.cpp
@@ -33,6 +33,7 @@
 #include "memory/resourceArea.hpp"
 #include "oops/markOop.hpp"
 #include "oops/oop.inline.hpp"
+#include "runtime/mutexLocker.hpp"
 #include "runtime/thread.inline.hpp"
 #include "runtime/vmThread.hpp"
 
@@ -50,8 +51,8 @@ EventEmitter::~EventEmitter() {
 }
 
 void EventEmitter::emit(ObjectSampler* sampler, int64_t cutoff_ticks, bool emit_all) {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
   assert(sampler != NULL, "invariant");
-
   ResourceMark rm;
   EdgeStore edge_store;
   if (cutoff_ticks <= 0) {
@@ -67,6 +68,7 @@ void EventEmitter::emit(ObjectSampler* sampler, int64_t cutoff_ticks, bool emit_
 }
 
 size_t EventEmitter::write_events(ObjectSampler* object_sampler, EdgeStore* edge_store, bool emit_all) {
+  assert_locked_or_safepoint(JfrStream_lock);
   assert(_thread == Thread::current(), "invariant");
   assert(_thread->jfr_thread_local() == _jfr_thread_local, "invariant");
   assert(object_sampler != NULL, "invariant");
diff --git a/src/share/vm/jfr/leakprofiler/checkpoint/objectSampleCheckpoint.cpp b/src/share/vm/jfr/leakprofiler/checkpoint/objectSampleCheckpoint.cpp
index 6c38cc67772e8d061144b4e0ae2f1512eedfdb08..835950fd0caf244d9ced20d58fa0b0c87fef8529 100644
--- a/src/share/vm/jfr/leakprofiler/checkpoint/objectSampleCheckpoint.cpp
+++ b/src/share/vm/jfr/leakprofiler/checkpoint/objectSampleCheckpoint.cpp
@@ -37,6 +37,7 @@
 #include "jfr/recorder/stacktrace/jfrStackTraceRepository.hpp"
 #include "jfr/utilities/jfrHashtable.hpp"
 #include "jfr/utilities/jfrTypes.hpp"
+#include "runtime/mutexLocker.hpp"
 #include "runtime/safepoint.hpp"
 #include "runtime/semaphore.hpp"
 #include "runtime/thread.hpp"
@@ -272,7 +273,7 @@ void StackTraceBlobInstaller::install(ObjectSample* sample) {
   }
   const JfrStackTrace* const stack_trace = resolve(sample);
   DEBUG_ONLY(validate_stack_trace(sample, stack_trace));
-  JfrCheckpointWriter writer(false, true, Thread::current());
+  JfrCheckpointWriter writer;
   writer.write_type(TYPE_STACKTRACE);
   writer.write_count(1);
   ObjectSampleCheckpoint::write_stacktrace(stack_trace, writer);
@@ -292,6 +293,7 @@ static void install_stack_traces(const ObjectSampler* sampler, JfrStackTraceRepo
 
 // caller needs ResourceMark
 void ObjectSampleCheckpoint::on_rotation(const ObjectSampler* sampler, JfrStackTraceRepository& stack_trace_repo) {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
   assert(sampler != NULL, "invariant");
   assert(LeakProfiler::is_running(), "invariant");
   install_stack_traces(sampler, stack_trace_repo);
@@ -389,7 +391,7 @@ class BlobWriter {
 static void write_sample_blobs(const ObjectSampler* sampler, bool emit_all, Thread* thread) {
   // sample set is predicated on time of last sweep
   const jlong last_sweep = emit_all ? max_jlong : sampler->last_sweep().value();
-  JfrCheckpointWriter writer(false, false, thread);
+  JfrCheckpointWriter writer(thread, false);
   BlobWriter cbw(sampler, writer, last_sweep);
   iterate_samples(cbw, true);
   // reset blob write states
@@ -398,13 +400,14 @@ static void write_sample_blobs(const ObjectSampler* sampler, bool emit_all, Thre
 }
 
 void ObjectSampleCheckpoint::write(const ObjectSampler* sampler, EdgeStore* edge_store, bool emit_all, Thread* thread) {
+  assert_locked_or_safepoint(JfrStream_lock);
   assert(sampler != NULL, "invariant");
   assert(edge_store != NULL, "invariant");
   assert(thread != NULL, "invariant");
   write_sample_blobs(sampler, emit_all, thread);
   // write reference chains
   if (!edge_store->is_empty()) {
-    JfrCheckpointWriter writer(false, true, thread);
+    JfrCheckpointWriter writer(thread);
     ObjectSampleWriter osw(writer, edge_store);
     edge_store->iterate(osw);
   }
diff --git a/src/share/vm/jfr/leakprofiler/checkpoint/objectSampleWriter.cpp b/src/share/vm/jfr/leakprofiler/checkpoint/objectSampleWriter.cpp
index 3cfd560116ce4d283ec60d37ca1ff0748c69e2d3..bcad2855eff5357c24f438d59cfb05750bf98ee3 100644
--- a/src/share/vm/jfr/leakprofiler/checkpoint/objectSampleWriter.cpp
+++ b/src/share/vm/jfr/leakprofiler/checkpoint/objectSampleWriter.cpp
@@ -355,10 +355,6 @@ int __write_root_description_info__(JfrCheckpointWriter* writer, const void* di)
 
 static traceid get_gc_root_description_info_id(const Edge& edge, traceid id) {
   assert(edge.is_root(), "invariant");
-  if (EdgeUtils::is_leak_edge(edge)) {
-    return 0;
-  }
-
   if (root_infos == NULL) {
     root_infos = new RootDescriptionInfo();
   }
@@ -606,8 +602,8 @@ class RootType : public JfrSerializer {
 static void register_serializers() {
   static bool is_registered = false;
   if (!is_registered) {
-    JfrSerializer::register_serializer(TYPE_OLDOBJECTROOTSYSTEM, false, true, new RootSystemType());
-    JfrSerializer::register_serializer(TYPE_OLDOBJECTROOTTYPE, false, true, new RootType());
+    JfrSerializer::register_serializer(TYPE_OLDOBJECTROOTSYSTEM, true, new RootSystemType());
+    JfrSerializer::register_serializer(TYPE_OLDOBJECTROOTTYPE, true, new RootType());
     is_registered = true;
   }
 }
diff --git a/src/share/vm/jfr/leakprofiler/checkpoint/rootResolver.cpp b/src/share/vm/jfr/leakprofiler/checkpoint/rootResolver.cpp
index e3a56afd0c525714a3fd787696e4a3e6bd6e3353..083443153b5cc1e90ace5c0a7a905edc321972b6 100644
--- a/src/share/vm/jfr/leakprofiler/checkpoint/rootResolver.cpp
+++ b/src/share/vm/jfr/leakprofiler/checkpoint/rootResolver.cpp
@@ -27,6 +27,7 @@
 //#include "gc_interface/strongRootsScope.hpp"
 #include "jfr/leakprofiler/utilities/unifiedOop.hpp"
 #include "jfr/leakprofiler/checkpoint/rootResolver.hpp"
+#include "jfr/utilities/jfrThreadIterator.hpp"
 #include "memory/iterator.hpp"
 #include "oops/klass.hpp"
 #include "oops/oop.hpp"
@@ -253,8 +254,9 @@ class ReferenceToThreadRootClosure : public StackObj {
  public:
   ReferenceToThreadRootClosure(RootCallback& callback) :_callback(callback), _complete(false) {
     assert_locked_or_safepoint(Threads_lock);
-    for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
-      if (do_thread_roots(thread)) {
+    JfrJavaThreadIterator iter;
+    while (iter.has_next()) {
+      if (do_thread_roots(iter.next())) {
         return;
       }
     }
diff --git a/src/share/vm/jfr/leakprofiler/leakProfiler.cpp b/src/share/vm/jfr/leakprofiler/leakProfiler.cpp
index 46ad79aa6eabf33de879d4ef10d84f87503b1992..822c78035a97c8462d05011dbe70933bd8af1175 100644
--- a/src/share/vm/jfr/leakprofiler/leakProfiler.cpp
+++ b/src/share/vm/jfr/leakprofiler/leakProfiler.cpp
@@ -30,6 +30,7 @@
 #include "jfr/leakprofiler/sampling/objectSampler.hpp"
 #include "jfr/recorder/service/jfrOptionSet.hpp"
 #include "memory/iterator.hpp"
+#include "runtime/mutexLocker.hpp"
 #include "runtime/thread.inline.hpp"
 #include "runtime/vmThread.hpp"
 
@@ -81,6 +82,7 @@ void LeakProfiler::emit_events(int64_t cutoff_ticks, bool emit_all) {
   if (!is_running()) {
     return;
   }
+  MutexLocker lock(JfrStream_lock);
   // exclusive access to object sampler instance
   ObjectSampler* const sampler = ObjectSampler::acquire();
   assert(sampler != NULL, "invariant");
diff --git a/src/share/vm/jfr/leakprofiler/sampling/objectSampler.cpp b/src/share/vm/jfr/leakprofiler/sampling/objectSampler.cpp
index 89653a6f6e04997803ae6faddcd7b5cc30078b69..3137e20ff4e5b804585c630b120a22281464eb31 100644
--- a/src/share/vm/jfr/leakprofiler/sampling/objectSampler.cpp
+++ b/src/share/vm/jfr/leakprofiler/sampling/objectSampler.cpp
@@ -108,6 +108,9 @@ static traceid get_thread_id(JavaThread* thread) {
   }
   const JfrThreadLocal* const tl = thread->jfr_thread_local();
   assert(tl != NULL, "invariant");
+  if (tl->is_excluded()) {
+    return 0;
+  }
   if (!tl->has_thread_blob()) {
     JfrCheckpointManager::create_thread_blob(thread);
   }
diff --git a/src/share/vm/jfr/metadata/jfrSerializer.hpp b/src/share/vm/jfr/metadata/jfrSerializer.hpp
index f5a4d7d9f2475f7fe9277d31bc37b13db9644507..2cada944663783eec98f97d4af9ccbb4d520f37d 100644
--- a/src/share/vm/jfr/metadata/jfrSerializer.hpp
+++ b/src/share/vm/jfr/metadata/jfrSerializer.hpp
@@ -70,7 +70,8 @@
 class JfrSerializer : public CHeapObj<mtTracing> {
  public:
   virtual ~JfrSerializer() {}
-  static bool register_serializer(JfrTypeId id, bool require_safepoint, bool permit_cache, JfrSerializer* serializer);
+  virtual void on_rotation() {}
+  static bool register_serializer(JfrTypeId id, bool permit_cache, JfrSerializer* serializer);
   virtual void serialize(JfrCheckpointWriter& writer) = 0;
 };
 
diff --git a/src/share/vm/jfr/metadata/metadata.xml b/src/share/vm/jfr/metadata/metadata.xml
index 8d97a420c9b01c05a0256b2bc9dd00ba1831b8ba..26115aed613cdb315f384c93d20ed117e50f5efc 100644
--- a/src/share/vm/jfr/metadata/metadata.xml
+++ b/src/share/vm/jfr/metadata/metadata.xml
@@ -154,7 +154,7 @@
     <Field type="string" name="newValue" label="New Value" />
     <Field type="FlagValueOrigin" name="origin" label="Origin" />
   </Event>
- 
+
   <Type name="VirtualSpace">
     <Field type="ulong" contentType="address" name="start" label="Start Address" description="Start address of the virtual space" />
     <Field type="ulong" contentType="address" name="committedEnd" label="Committed End Address" description="End address of the committed memory for the virtual space" />
@@ -162,27 +162,27 @@
     <Field type="ulong" contentType="address" name="reservedEnd" label="Reserved End Address" description="End address of the reserved memory for the virtual space" />
     <Field type="ulong" contentType="bytes" name="reservedSize" label="Reserved Size" description="Size of the reserved memory for the virtual space" />
   </Type>
-  
+
   <Type name="ObjectSpace">
     <Field type="ulong" contentType="address" name="start" label="Start Address" description="Start address of the space" />
     <Field type="ulong" contentType="address" name="end" label="End Address" description="End address of the space" />
     <Field type="ulong" contentType="bytes" name="used" label="Used" description="Bytes allocated by objects in the space" />
     <Field type="ulong" contentType="bytes" name="size" label="Size" description="Size of the space" />
   </Type>
-  
+
   <Event name="GCHeapSummary" category="Java Virtual Machine, GC, Heap" label="Heap Summary" startTime="false">
     <Field type="uint" name="gcId" label="GC Identifier" relation="GcId" />
     <Field type="GCWhen" name="when" label="When" />
     <Field type="VirtualSpace" struct="true" name="heapSpace" label="Heap Space" />
     <Field type="ulong" contentType="bytes" name="heapUsed" label="Heap Used" description="Bytes allocated by objects in the heap" />
   </Event>
- 
+
   <Type name="MetaspaceSizes">
     <Field type="ulong" contentType="bytes" name="committed" label="Committed" description="Committed memory for this space" />
     <Field type="ulong" contentType="bytes" name="used" label="Used" description="Bytes allocated by objects in the space" />
     <Field type="ulong" contentType="bytes" name="reserved" label="Reserved" description="Reserved memory for this space" />
   </Type>
- 
+
   <Event name="MetaspaceSummary" category="Java Virtual Machine, GC, Heap" label="Metaspace Summary" startTime="false">
     <Field type="uint" name="gcId" label="GC Identifier" relation="GcId" />
     <Field type="GCWhen" name="when" label="When" />
@@ -477,7 +477,7 @@
     <Field type="string" name="failureMessage" label="Failure Message" />
     <Field type="uint" name="compileId" label="Compilation Identifier" relation="CompileId" />
   </Event>
-  
+
   <Type name="CalleeMethod">
     <Field type="string" name="type" label="Class" />
     <Field type="string" name="name" label="Method Name" />
@@ -595,21 +595,21 @@
     <Field type="OldObjectGcRoot" name="root" label="GC Root" />
   </Event>
 
-  <Event name="DumpReason" category="Flight Recorder" label="Recording Reason" 
-         description="Who requested the recording and why" 
+  <Event name="DumpReason" category="Flight Recorder" label="Recording Reason"
+         description="Who requested the recording and why"
          startTime="false">
     <Field type="string" name="reason" label="Reason" description="Reason for writing recording data to disk" />
     <Field type="int" name="recordingId" label="Recording Id" description="Id of the recording that triggered the dump, or -1 if it was not related to a recording" />
   </Event>
 
-  <Event name="DataLoss" category="Flight Recorder" label="Data Loss" 
+  <Event name="DataLoss" category="Flight Recorder" label="Data Loss"
          description="Data could not be copied out from a buffer, typically because of contention"
          startTime="false">
     <Field type="ulong" contentType="bytes" name="amount" label="Amount" description="Amount lost data" />
     <Field type="ulong" contentType="bytes" name="total" label="Total" description="Total lost amount for thread" />
   </Event>
 
-  <Event name="JVMInformation" category="Java Virtual Machine" label="JVM Information" 
+  <Event name="JVMInformation" category="Java Virtual Machine" label="JVM Information"
          description="Description of JVM and the Java application"
          period="endChunk">
     <Field type="string" name="jvmName" label="JVM Name" />
@@ -930,6 +930,42 @@
     <Field type="ulong" name="value" label="Value" />
   </Event>
 
+  <Event name="Flush" category="Flight Recorder" label="Flush" thread="false" experimental="true">
+    <Field type="ulong" name="flushId" label="Flush Identifier" relation="FlushId" />
+    <Field type="ulong" name="elements" label="Elements Written" />
+    <Field type="ulong" contentType="bytes" name="size" label="Size Written" />
+  </Event>
+
+  <Event name="FlushStorage" category="Flight Recorder" label="Flush Storage" thread="false" experimental="true">
+    <Field type="ulong" name="flushId" label="Flush Identifier" relation="FlushId" />
+    <Field type="ulong" name="elements" label="Elements Written" />
+    <Field type="ulong" contentType="bytes" name="size" label="Size Written" />
+  </Event>
+
+  <Event name="FlushStacktrace" category="Flight Recorder" label="Flush Stacktrace" thread="false" experimental="true">
+    <Field type="ulong" name="flushId" label="Flush Identifier" relation="FlushId" />
+    <Field type="ulong" name="elements" label="Elements Written" />
+    <Field type="ulong" contentType="bytes" name="size" label="Size Written" />
+  </Event>
+
+  <Event name="FlushStringPool" category="Flight Recorder" label="Flush String Pool" thread="false" experimental="true">
+    <Field type="ulong" name="flushId" label="Flush Identifier" relation="FlushId" />
+    <Field type="ulong" name="elements" label="Elements Written" />
+    <Field type="ulong" contentType="bytes" name="size" label="Size Written" />
+  </Event>
+
+  <Event name="FlushMetadata" category="Flight Recorder" label="Flush Metadata" thread="false" experimental="true">
+    <Field type="ulong" name="flushId" label="Flush Identifier" relation="FlushId" />
+    <Field type="ulong" name="elements" label="Elements Written" />
+    <Field type="ulong" contentType="bytes" name="size" label="Size Written" />
+  </Event>
+
+  <Event name="FlushTypeSet" category="Flight Recorder" label="Flush Type Set" thread="false" experimental="true">
+    <Field type="ulong" name="flushId" label="Flush Identifier" relation="FlushId" />
+    <Field type="ulong" name="elements" label="Elements Written" />
+    <Field type="ulong" contentType="bytes" name="size" label="Size Written" />
+  </Event>
+
   <Type name="ZStatisticsCounterType" label="Z Statistics Counter">
     <Field type="string" name="counter" label="Counter" />
   </Type>
@@ -1112,34 +1148,40 @@
     <Field type="int" name="bytecodeIndex" label="Bytecode Index" />
     <Field type="FrameType" name="type" label="Frame Type" />
   </Type>
+
+  <Type name="ChunkHeader" label="Chunk Header">
+    <Field type="byte" array="true" name="payload" label="Payload" />
+  </Type>
  
   <Relation name="JavaMonitorAddress"/>
   <Relation name="SafepointId"/>
   <Relation name="GcId"/>
   <Relation name="CompileId" />
   <Relation name="SweepId"/>
- 
+  <Relation name="FlushId"/>
+
   <XmlType name="Package" parameterType="const PackageEntry*" fieldType="const PackageEntry*"/>
-  <XmlType name="Class" javaType="java.lang.Class" parameterType="const Klass*" fieldType="const Klass*"/> 
-  <XmlType name="ClassLoader" parameterType="const ClassLoaderData*" fieldType="const ClassLoaderData*"/> 
-  <XmlType name="Method" parameterType="const Method*" fieldType="const Method*"/> 
-  <XmlType name="Thread" javaType="java.lang.Thread" parameterType="u8" fieldType="u8"/> 
-  <XmlType name="Tickspan" contentType="tickspan" javaType="long" parameterType="const Tickspan&amp;" fieldType="Tickspan"/> 
-  <XmlType name="Ticks" contentType="tickstamp" javaType="long" parameterType="const Ticks&amp;" fieldType="Ticks"/> 
-  <XmlType name="ulong" javaType="long" unsigned="true" parameterType="u8" fieldType="u8"/> 
-  <XmlType name="uint" javaType="int" unsigned="true" parameterType="unsigned" fieldType="unsigned"/> 
-  <XmlType name="ushort" javaType="short" unsigned="true" parameterType="u2" fieldType="u2"/> 
-  <XmlType name="ubyte" javaType="byte" unsigned="true" parameterType="u1" fieldType="u1"/> 
-  <XmlType name="long" javaType="long" parameterType="s8" fieldType="s8"/> 
-  <XmlType name="int" javaType="int" parameterType="s4" fieldType="s4"/> 
-  <XmlType name="short" javaType="short" parameterType="s2" fieldType="s2"/> 
-  <XmlType name="byte" javaType="byte"  parameterType="s1" fieldType="s1"/> 
-  <XmlType name="double" javaType="double" parameterType="double" fieldType="double"/> 
-  <XmlType name="float" javaType="float"  parameterType="float" fieldType="float"/> 
-  <XmlType name="boolean" javaType="boolean" parameterType="bool" fieldType="bool"/> 
-  <XmlType name="char" javaType="char" parameterType="char" fieldType="char"/> 
-  <XmlType name="string" javaType="java.lang.String" parameterType="const char*" fieldType="const char*"/> 
- 
+  <XmlType name="Class" javaType="java.lang.Class" parameterType="const Klass*" fieldType="const Klass*"/>
+  <XmlType name="Module"  parameterType="const ModuleEntry*" fieldType="const ModuleEntry*"/>
+  <XmlType name="ClassLoader" parameterType="const ClassLoaderData*" fieldType="const ClassLoaderData*"/>
+  <XmlType name="Method" parameterType="const Method*" fieldType="const Method*"/>
+  <XmlType name="Thread" javaType="java.lang.Thread" parameterType="u8" fieldType="u8"/>
+  <XmlType name="Tickspan" contentType="tickspan" javaType="long" parameterType="const Tickspan&amp;" fieldType="Tickspan"/>
+  <XmlType name="Ticks" contentType="tickstamp" javaType="long" parameterType="const Ticks&amp;" fieldType="Ticks"/>
+  <XmlType name="ulong" javaType="long" unsigned="true" parameterType="u8" fieldType="u8"/>
+  <XmlType name="uint" javaType="int" unsigned="true" parameterType="unsigned" fieldType="unsigned"/>
+  <XmlType name="ushort" javaType="short" unsigned="true" parameterType="u2" fieldType="u2"/>
+  <XmlType name="ubyte" javaType="byte" unsigned="true" parameterType="u1" fieldType="u1"/>
+  <XmlType name="long" javaType="long" parameterType="s8" fieldType="s8"/>
+  <XmlType name="int" javaType="int" parameterType="s4" fieldType="s4"/>
+  <XmlType name="short" javaType="short" parameterType="s2" fieldType="s2"/>
+  <XmlType name="byte" javaType="byte"  parameterType="s1" fieldType="s1"/>
+  <XmlType name="double" javaType="double" parameterType="double" fieldType="double"/>
+  <XmlType name="float" javaType="float"  parameterType="float" fieldType="float"/>
+  <XmlType name="boolean" javaType="boolean" parameterType="bool" fieldType="bool"/>
+  <XmlType name="char" javaType="char" parameterType="char" fieldType="char"/>
+  <XmlType name="string" javaType="java.lang.String" parameterType="const char*" fieldType="const char*"/>
+
   <XmlContentType name="bytes" annotation="jdk.jfr.DataAmount(BYTES)" />
   <XmlContentType name="tickstamp" annotation="jdk.jfr.Timestamp(TICKS)" />
   <XmlContentType name="epochmillis" annotation="jdk.jfr.Timestamp(MILLISECONDS_SINCE_EPOCH)" />
@@ -1151,5 +1193,5 @@
   <XmlContentType name="hertz" annotation="jdk.jfr.Frequency" />
   <XmlContentType name="bytes-per-second" annotation="jdk.jfr.DataAmount(BYTES), jdk.jfr.Frequency" />
   <XmlContentType name="bits-per-second" annotation="jdk.jfr.DataAmount(BITS), jdk.jfr.Frequency" />
- 
+
 </Metadata>
diff --git a/src/share/vm/jfr/periodic/jfrNetworkUtilization.cpp b/src/share/vm/jfr/periodic/jfrNetworkUtilization.cpp
index 6a7c0d84f3606d369e55dd8a36313ac04ce5958e..38bc40045b1505b867fec94a2d0e6776bd397510 100644
--- a/src/share/vm/jfr/periodic/jfrNetworkUtilization.cpp
+++ b/src/share/vm/jfr/periodic/jfrNetworkUtilization.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -38,7 +38,7 @@ struct InterfaceEntry {
   traceid id;
   uint64_t bytes_in;
   uint64_t bytes_out;
-  bool in_use;
+  mutable bool written;
 };
 
 static GrowableArray<InterfaceEntry>* _interfaces = NULL;
@@ -70,7 +70,7 @@ static InterfaceEntry& new_entry(const NetworkInterface* iface, GrowableArray<In
   entry.id = ++interface_id;
   entry.bytes_in = iface->get_bytes_in();
   entry.bytes_out = iface->get_bytes_out();
-  entry.in_use = false;
+  entry.written = false;
   return _interfaces->at(_interfaces->append(entry));
 }
 
@@ -107,46 +107,46 @@ static uint64_t rate_per_second(uint64_t current, uint64_t old, const JfrTickspa
   return ((current - old) * NANOSECS_PER_SEC) / interval.nanoseconds();
 }
 
-static bool get_interfaces(NetworkInterface** network_interfaces) {
-  const int ret_val = JfrOSInterface::network_utilization(network_interfaces);
-  if (ret_val == OS_ERR) {
-    if (LogJFR) tty->print_cr("Unable to generate network utilization events");
-    return false;
-  }
-  return ret_val != FUNCTIONALITY_NOT_IMPLEMENTED;
-}
-
 class JfrNetworkInterfaceName : public JfrSerializer {
  public:
-  void serialize(JfrCheckpointWriter& writer) {
-    assert(_interfaces != NULL, "invariant");
-    const JfrCheckpointContext ctx = writer.context();
-    const intptr_t count_offset = writer.reserve(sizeof(u4)); // Don't know how many yet
-    int active_interfaces = 0;
-    for (int i = 0; i < _interfaces->length(); ++i) {
-      InterfaceEntry& entry = _interfaces->at(i);
-      if (entry.in_use) {
-        entry.in_use = false;
-        writer.write_key(entry.id);
-        writer.write(entry.name);
-        ++active_interfaces;
-      }
-    }
-    if (active_interfaces == 0) {
-      // nothing to write, restore context
-      writer.set_context(ctx);
-      return;
-    }
-    writer.write_count(active_interfaces, count_offset);
-  }
+   void serialize(JfrCheckpointWriter& writer) {} // we write each constant lazily
+
+   void on_rotation() {
+     for (int i = 0; i < _interfaces->length(); ++i) {
+       const InterfaceEntry& entry = _interfaces->at(i);
+       if (entry.written) {
+         entry.written = false;
+       }
+     }
+   }
 };
 
 static bool register_network_interface_name_serializer() {
   assert(_interfaces != NULL, "invariant");
   return JfrSerializer::register_serializer(TYPE_NETWORKINTERFACENAME,
-                                            false, // require safepoint
-                                            false, // disallow caching; we want a callback every rotation
-                                            new JfrNetworkInterfaceName());
+    false, // disallow caching; we want a callback every rotation
+    new JfrNetworkInterfaceName());
+}
+
+static void write_interface_constant(const InterfaceEntry& entry) {
+  if (entry.written) {
+    return;
+  }
+  JfrCheckpointWriter writer;
+  writer.write_type(TYPE_NETWORKINTERFACENAME);
+  writer.write_count(1);
+  writer.write_key(entry.id);
+  writer.write(entry.name);
+  entry.written = true;
+}
+
+static bool get_interfaces(NetworkInterface** network_interfaces) {
+  const int ret_val = JfrOSInterface::network_utilization(network_interfaces);
+  if (ret_val == OS_ERR) {
+    if (LogJFR) tty->print_cr("Unable to generate network utilization events");
+    return false;
+  }
+  return ret_val != FUNCTIONALITY_NOT_IMPLEMENTED;
 }
 
 void JfrNetworkUtilization::send_events() {
@@ -168,7 +168,7 @@ void JfrNetworkUtilization::send_events() {
       const uint64_t read_rate = rate_per_second(current_bytes_in, entry.bytes_in, interval);
       const uint64_t write_rate = rate_per_second(current_bytes_out, entry.bytes_out, interval);
       if (read_rate > 0 || write_rate > 0) {
-        entry.in_use = true;
+        write_interface_constant(entry);
         EventNetworkUtilization event(UNTIMED);
         event.set_starttime(cur_time);
         event.set_endtime(cur_time);
diff --git a/src/share/vm/jfr/periodic/jfrPeriodic.cpp b/src/share/vm/jfr/periodic/jfrPeriodic.cpp
index 92f516361dcb3271ebcfab37291d4fe7ac80c80c..e3add031dfd2f725b88f0a9ff25d6515b8838058 100644
--- a/src/share/vm/jfr/periodic/jfrPeriodic.cpp
+++ b/src/share/vm/jfr/periodic/jfrPeriodic.cpp
@@ -40,6 +40,7 @@
 #include "jfr/periodic/jfrNetworkUtilization.hpp"
 #include "jfr/recorder/jfrRecorder.hpp"
 #include "jfr/support/jfrThreadId.hpp"
+#include "jfr/utilities/jfrThreadIterator.hpp"
 #include "jfr/utilities/jfrTime.hpp"
 #include "jfrfiles/jfrPeriodic.hpp"
 #include "memory/heapInspection.hpp"
@@ -393,13 +394,12 @@ TRACE_REQUEST_FUNC(ThreadAllocationStatistics) {
   GrowableArray<jlong> allocated(initial_size);
   GrowableArray<traceid> thread_ids(initial_size);
   JfrTicks time_stamp = JfrTicks::now();
-  {
-    // Collect allocation statistics while holding threads lock
-    MutexLockerEx ml(Threads_lock);
-    for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
-      allocated.append(thread->cooked_allocated_bytes());
-      thread_ids.append(JFR_THREAD_ID(thread));
-    }
+  JfrJavaThreadIterator iter;
+  while (iter.has_next()) {
+    JavaThread* const jt = iter.next();
+    assert(jt != NULL, "invariant");
+    allocated.append(jt->cooked_allocated_bytes());
+    thread_ids.append(JFR_THREAD_ID(jt));
   }
 
   // Write allocation statistics to buffer.
diff --git a/src/share/vm/jfr/periodic/jfrThreadCPULoadEvent.cpp b/src/share/vm/jfr/periodic/jfrThreadCPULoadEvent.cpp
index 2d80ceca90f9daf851fd56704eaf705de5c8ab57..b075ecbc50dbc3e083f9bbe51fe9d3a8c170fdda 100644
--- a/src/share/vm/jfr/periodic/jfrThreadCPULoadEvent.cpp
+++ b/src/share/vm/jfr/periodic/jfrThreadCPULoadEvent.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
diff --git a/src/share/vm/jfr/periodic/sampling/jfrThreadSampler.cpp b/src/share/vm/jfr/periodic/sampling/jfrThreadSampler.cpp
index 969ce8ff6d61a0da63cff4bb9766151c74ff6602..7e7a9fe85e01d661044ae9f04cc320ccaff4646a 100644
--- a/src/share/vm/jfr/periodic/sampling/jfrThreadSampler.cpp
+++ b/src/share/vm/jfr/periodic/sampling/jfrThreadSampler.cpp
@@ -30,6 +30,7 @@
 #include "jfr/recorder/service/jfrOptionSet.hpp"
 #include "jfr/recorder/stacktrace/jfrStackTraceRepository.hpp"
 #include "jfr/support/jfrThreadId.hpp"
+#include "jfr/support/jfrThreadLocal.hpp"
 #include "jfr/utilities/jfrTime.hpp"
 #include "runtime/frame.inline.hpp"
 #include "runtime/os.hpp"
@@ -353,9 +354,14 @@ static void clear_transition_block(JavaThread* jt) {
   }
 }
 
+static bool is_excluded(JavaThread* thread) {
+  assert(thread != NULL, "invariant");
+  return thread->is_hidden_from_external_view() || thread->in_deopt_handler() || thread->jfr_thread_local()->is_excluded();
+}
+
 bool JfrThreadSampleClosure::do_sample_thread(JavaThread* thread, JfrStackFrame* frames, u4 max_frames, JfrSampleType type) {
   assert(Threads_lock->owned_by_self(), "Holding the thread table lock.");
-  if (thread->is_hidden_from_external_view() || thread->in_deopt_handler()) {
+  if (is_excluded(thread)) {
     return false;
   }
 
diff --git a/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointManager.cpp b/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointManager.cpp
index c28dfb81b336e5d7655b912f1ea65b95f94fa7f0..4e98a4e8bed69d93144b9e738d1912b022ef12ea 100644
--- a/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointManager.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointManager.cpp
@@ -37,10 +37,13 @@
 #include "jfr/recorder/storage/jfrMemorySpace.inline.hpp"
 #include "jfr/recorder/storage/jfrStorageUtils.inline.hpp"
 #include "jfr/utilities/jfrBigEndian.hpp"
+#include "jfr/utilities/jfrIterator.hpp"
+#include "jfr/utilities/jfrThreadIterator.hpp"
 #include "jfr/utilities/jfrTypes.hpp"
+#include "jfr/writers/jfrJavaEventWriter.hpp"
 #include "memory/resourceArea.hpp"
 #include "runtime/handles.inline.hpp"
-#include "runtime/mutexLocker.hpp"
+#include "runtime/mutex.hpp"
 #include "runtime/orderAccess.inline.hpp"
 #include "runtime/os.hpp"
 #include "runtime/safepoint.hpp"
@@ -167,7 +170,7 @@ static BufferPtr lease_free(size_t size, JfrCheckpointMspace* mspace, size_t ret
 }
 
 bool JfrCheckpointManager::use_epoch_transition_mspace(const Thread* thread) const {
-  return _service_thread != thread && OrderAccess::load_acquire((u1*)&_checkpoint_epoch_state) != JfrTraceIdEpoch::epoch();
+  return _service_thread != thread && _checkpoint_epoch_state != JfrTraceIdEpoch::epoch();
 }
 
 static const size_t lease_retry = 10;
@@ -180,12 +183,24 @@ BufferPtr JfrCheckpointManager::lease_buffer(Thread* thread, size_t size /* 0 */
   return lease_free(size, manager._free_list_mspace, lease_retry, thread);
 }
 
+JfrCheckpointMspace* JfrCheckpointManager::lookup(BufferPtr old) const {
+  assert(old != NULL, "invariant");
+  return _free_list_mspace->in_free_list(old) ? _free_list_mspace : _epoch_transition_mspace;
+}
+
+BufferPtr JfrCheckpointManager::lease_buffer(BufferPtr old, Thread* thread, size_t size /* 0 */) {
+  assert(old != NULL, "invariant");
+  JfrCheckpointMspace* mspace = instance().lookup(old);
+  assert(mspace != NULL, "invariant");
+  return lease_free(size, mspace, lease_retry, thread);
+}
+
 /*
-* If the buffer was a "lease" from the free list, release back.
-*
-* The buffer is effectively invalidated for the thread post-return,
-* and the caller should take means to ensure that it is not referenced.
-*/
+ * If the buffer was a lease, release back.
+ *
+ * The buffer is effectively invalidated for the thread post-return,
+ * and the caller should take means to ensure that it is not referenced.
+ */
 static void release(BufferPtr const buffer, Thread* thread) {
   DEBUG_ONLY(assert_release(buffer);)
   buffer->clear_lease();
@@ -201,7 +216,7 @@ BufferPtr JfrCheckpointManager::flush(BufferPtr old, size_t used, size_t request
     return NULL;
   }
   // migration of in-flight information
-  BufferPtr const new_buffer = lease_buffer(thread, used + requested);
+  BufferPtr const new_buffer = lease_buffer(old, thread, used + requested);
   if (new_buffer != NULL) {
     migrate_outstanding_writes(old, new_buffer, used, requested);
   }
@@ -212,8 +227,8 @@ BufferPtr JfrCheckpointManager::flush(BufferPtr old, size_t used, size_t request
 // offsets into the JfrCheckpointEntry
 static const juint starttime_offset = sizeof(jlong);
 static const juint duration_offset = starttime_offset + sizeof(jlong);
-static const juint flushpoint_offset = duration_offset + sizeof(jlong);
-static const juint types_offset = flushpoint_offset + sizeof(juint);
+static const juint checkpoint_type_offset = duration_offset + sizeof(jlong);
+static const juint types_offset = checkpoint_type_offset + sizeof(juint);
 static const juint payload_offset = types_offset + sizeof(juint);
 
 template <typename Return>
@@ -233,21 +248,21 @@ static jlong duration(const u1* data) {
   return read_data<jlong>(data + duration_offset);
 }
 
-static bool is_flushpoint(const u1* data) {
-  return read_data<juint>(data + flushpoint_offset) == (juint)1;
+static u1 checkpoint_type(const u1* data) {
+  return read_data<u1>(data + checkpoint_type_offset);
 }
 
 static juint number_of_types(const u1* data) {
   return read_data<juint>(data + types_offset);
 }
 
-static void write_checkpoint_header(JfrChunkWriter& cw, int64_t offset_prev_cp_event, const u1* data) {
+static void write_checkpoint_header(JfrChunkWriter& cw, int64_t delta_to_last_checkpoint, const u1* data) {
   cw.reserve(sizeof(u4));
   cw.write<u8>(EVENT_CHECKPOINT);
   cw.write(starttime(data));
   cw.write(duration(data));
-  cw.write(offset_prev_cp_event);
-  cw.write(is_flushpoint(data));
+  cw.write(delta_to_last_checkpoint);
+  cw.write(checkpoint_type(data));
   cw.write(number_of_types(data));
 }
 
@@ -260,9 +275,9 @@ static size_t write_checkpoint_event(JfrChunkWriter& cw, const u1* data) {
   assert(data != NULL, "invariant");
   const int64_t event_begin = cw.current_offset();
   const int64_t last_checkpoint_event = cw.last_checkpoint_offset();
-  const int64_t delta = last_checkpoint_event == 0 ? 0 : last_checkpoint_event - event_begin;
+  const int64_t delta_to_last_checkpoint = last_checkpoint_event == 0 ? 0 : last_checkpoint_event - event_begin;
   const int64_t checkpoint_size = total_size(data);
-  write_checkpoint_header(cw, delta, data);
+  write_checkpoint_header(cw, delta_to_last_checkpoint, data);
   write_checkpoint_content(cw, data, checkpoint_size);
   const int64_t event_size = cw.current_offset() - event_begin;
   cw.write_padded_at_offset<u4>(event_size, event_begin);
@@ -333,6 +348,16 @@ size_t JfrCheckpointManager::write_epoch_transition_mspace() {
   return write_mspace_exclusive(_epoch_transition_mspace, _chunkwriter);
 }
 
+typedef MutexedWriteOp<WriteOperation> FlushOperation;
+
+size_t JfrCheckpointManager::flush() {
+  WriteOperation wo(_chunkwriter);
+  FlushOperation fo(wo);
+  assert(_free_list_mspace->is_full_empty(), "invariant");
+  process_free_list(fo, _free_list_mspace);
+  return wo.processed();
+}
+
 typedef DiscardOp<DefaultDiscarder<JfrBuffer> > DiscardOperation;
 size_t JfrCheckpointManager::clear() {
   JfrTypeSet::clear();
@@ -340,45 +365,121 @@ size_t JfrCheckpointManager::clear() {
   process_free_list(discarder, _free_list_mspace);
   process_free_list(discarder, _epoch_transition_mspace);
   synchronize_epoch();
-  return discarder.processed();
+  return discarder.elements();
 }
 
-size_t JfrCheckpointManager::write_types() {
-  JfrCheckpointWriter writer(false, true, Thread::current());
-  JfrTypeManager::write_types(writer);
+// Optimization for write_static_type_set() and write_threads() is to write
+// directly into the epoch transition mspace because we will immediately
+// serialize and reset this mspace post-write.
+static JfrBuffer* get_epoch_transition_buffer(JfrCheckpointMspace* mspace, Thread* t) {
+  assert(mspace != NULL, "invariant");
+  JfrBuffer* const buffer = mspace->free_head();
+  assert(buffer != NULL, "invariant");
+  buffer->acquire(t);
+  buffer->set_lease();
+  DEBUG_ONLY(assert_free_lease(buffer);)
+  return buffer;
+}
+
+bool JfrCheckpointManager::is_static_type_set_required() {
+  return JfrTypeManager::has_new_static_type();
+}
+
+size_t JfrCheckpointManager::write_static_type_set() {
+  Thread* const t = Thread::current();
+  ResourceMark rm(t);
+  HandleMark hm(t);
+  JfrCheckpointWriter writer(t, get_epoch_transition_buffer(_epoch_transition_mspace, t), STATICS);
+  JfrTypeManager::write_static_types(writer);
   return writer.used_size();
 }
 
-size_t JfrCheckpointManager::write_safepoint_types() {
-  // this is also a "flushpoint"
-  JfrCheckpointWriter writer(true, true, Thread::current());
-  JfrTypeManager::write_safepoint_types(writer);
+size_t JfrCheckpointManager::write_threads() {
+  Thread* const t = Thread::current();
+  ResourceMark rm(t);
+  HandleMark hm(t);
+  JfrCheckpointWriter writer(t, get_epoch_transition_buffer(_epoch_transition_mspace, t), THREADS);
+  JfrTypeManager::write_threads(writer);
   return writer.used_size();
 }
 
+size_t JfrCheckpointManager::write_static_type_set_and_threads() {
+  write_static_type_set();
+  write_threads();
+  return write_epoch_transition_mspace();
+}
+
+void JfrCheckpointManager::shift_epoch() {
+  debug_only(const u1 current_epoch = JfrTraceIdEpoch::current();)
+  JfrTraceIdEpoch::shift_epoch();
+  assert(current_epoch != JfrTraceIdEpoch::current(), "invariant");
+}
+
+void JfrCheckpointManager::flush_static_type_set() {
+  flush();
+}
+
+void JfrCheckpointManager::create_thread_blob(Thread* t) {
+  JfrTypeManager::create_thread_blob(t);
+}
+
+void JfrCheckpointManager::write_thread_checkpoint(Thread* t) {
+  JfrTypeManager::write_thread_checkpoint(t);
+}
+
+class JfrNotifyClosure : public ThreadClosure {
+ public:
+  void do_thread(Thread* t) {
+    assert(t != NULL, "invariant");
+    assert(t->is_Java_thread(), "invariant");
+    assert_locked_or_safepoint(Threads_lock);
+    JfrJavaEventWriter::notify((JavaThread*)t);
+  }
+};
+
+void JfrCheckpointManager::notify_threads() {
+  assert(SafepointSynchronize::is_at_safepoint(), "invariant");
+  JfrNotifyClosure tc;
+  JfrJavaThreadIterator iter;
+  while (iter.has_next()) {
+    tc.do_thread(iter.next());
+  }
+}
+
+void JfrCheckpointManager::on_rotation() {
+  assert(SafepointSynchronize::is_at_safepoint(), "invariant");
+  JfrTypeManager::on_rotation();
+  notify_threads();
+}
+
 void JfrCheckpointManager::write_type_set() {
   assert(!SafepointSynchronize::is_at_safepoint(), "invariant");
-  // can safepoint here
-  // TODO: CLDG lock does not exist in 11 - what shall we do?
-  // MutexLocker cld_lock(ClassLoaderDataGraph_lock);
-  MutexLocker package_table_lock(PackageTable_lock);
-  if (!LeakProfiler::is_running()) {
-    JfrCheckpointWriter writer(true, true, Thread::current());
-    JfrTypeSet::serialize(&writer, NULL, false);
-  } else {
+  if (LeakProfiler::is_running()) {
     Thread* const t = Thread::current();
-    JfrCheckpointWriter leakp_writer(false, true, t);
-    JfrCheckpointWriter writer(false, true, t);
-    JfrTypeSet::serialize(&writer, &leakp_writer, false);
+    // can safepoint here
+    // MutexLocker cld_lock(ClassLoaderDataGraph_lock);
+    // MutexLocker module_lock(Module_lock);
+    MutexLocker package_table_lock(PackageTable_lock);
+    JfrCheckpointWriter leakp_writer(t);
+    JfrCheckpointWriter writer(t);
+    JfrTypeSet::serialize(&writer, &leakp_writer, false, false);
     ObjectSampleCheckpoint::on_type_set(leakp_writer);
+  } else {
+    // can safepoint here
+    // MutexLocker cld_lock(ClassLoaderDataGraph_lock);
+    // MutexLocker module_lock(Module_lock);
+    MutexLocker package_table_lock(PackageTable_lock);
+    JfrCheckpointWriter writer(Thread::current());
+    JfrTypeSet::serialize(&writer, NULL, false, false);
   }
+  write();
 }
 
 void JfrCheckpointManager::write_type_set_for_unloaded_classes() {
   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint!");
-  JfrCheckpointWriter writer(false, true, Thread::current());
+  JfrCheckpointWriter writer(Thread::current());
   const JfrCheckpointContext ctx = writer.context();
-  JfrTypeSet::serialize(&writer, NULL, true);
+  JfrTypeSet::serialize(&writer, NULL, true, false);
   if (LeakProfiler::is_running()) {
     ObjectSampleCheckpoint::on_type_set_unload(writer);
   }
@@ -388,16 +489,20 @@ void JfrCheckpointManager::write_type_set_for_unloaded_classes() {
   }
 }
 
-void JfrCheckpointManager::create_thread_blob(JavaThread* jt) {
-  JfrTypeManager::create_thread_blob(jt);
-}
-
-void JfrCheckpointManager::write_thread_checkpoint(JavaThread* jt) {
-  JfrTypeManager::write_thread_checkpoint(jt);
+bool JfrCheckpointManager::is_type_set_required() {
+  return JfrTraceIdEpoch::has_changed_tag_state();
 }
 
-void JfrCheckpointManager::shift_epoch() {
-  debug_only(const u1 current_epoch = JfrTraceIdEpoch::current();)
-  JfrTraceIdEpoch::shift_epoch();
-  assert(current_epoch != JfrTraceIdEpoch::current(), "invariant");
+size_t JfrCheckpointManager::flush_type_set() {
+  assert(!SafepointSynchronize::is_at_safepoint(), "invariant");
+  size_t elements = 0;
+  {
+    JfrCheckpointWriter writer(Thread::current());
+    // can safepoint here
+    // MutexLocker cld_lock(ClassLoaderDataGraph_lock);
+    MutexLocker package_table_lock(PackageTable_lock);
+    elements = JfrTypeSet::serialize(&writer, NULL, false, true);
+  }
+  flush();
+  return elements;
 }
diff --git a/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointManager.hpp b/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointManager.hpp
index f90cdc9af38c21450925d713a773deac36953b80..5392f145eaedc282fdebeb28d7c7aeb11aa47c6d 100644
--- a/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointManager.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointManager.hpp
@@ -68,18 +68,29 @@ class JfrCheckpointManager : public JfrCHeapObj {
   void unlock();
   DEBUG_ONLY(bool is_locked() const;)
 
+  JfrCheckpointMspace* lookup(Buffer* old) const;
+  bool use_epoch_transition_mspace(const Thread* t) const;
+  size_t write_epoch_transition_mspace();
+
   static Buffer* lease_buffer(Thread* t, size_t size = 0);
+  static Buffer* lease_buffer(Buffer* old, Thread* t, size_t size = 0);
   static Buffer* flush(Buffer* old, size_t used, size_t requested, Thread* t);
 
   size_t clear();
   size_t write();
-  size_t write_epoch_transition_mspace();
-  size_t write_types();
-  size_t write_safepoint_types();
+  size_t flush();
+
+  bool is_static_type_set_required();
+  size_t write_static_type_set();
+  size_t write_threads();
+  size_t write_static_type_set_and_threads();
+  bool is_type_set_required();
   void write_type_set();
+  static void write_type_set_for_unloaded_classes();
+
   void shift_epoch();
   void synchronize_epoch();
-  bool use_epoch_transition_mspace(const Thread* t) const;
+  void notify_threads();
 
   JfrCheckpointManager(JfrChunkWriter& cw);
   ~JfrCheckpointManager();
@@ -87,14 +98,17 @@ class JfrCheckpointManager : public JfrCHeapObj {
   static JfrCheckpointManager& instance();
   static JfrCheckpointManager* create(JfrChunkWriter& cw);
   bool initialize();
+  void on_rotation();
   static void destroy();
 
  public:
+  size_t flush_type_set();
+  void flush_static_type_set();
+  static void create_thread_blob(Thread* t);
+  static void write_thread_checkpoint(Thread* t);
   void register_service_thread(const Thread* t);
-  static void write_type_set_for_unloaded_classes();
-  static void create_thread_blob(JavaThread* jt);
-  static void write_thread_checkpoint(JavaThread* jt);
 
+  friend class Jfr;
   friend class JfrRecorder;
   friend class JfrRecorderService;
   friend class JfrCheckpointFlush;
diff --git a/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointWriter.cpp b/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointWriter.cpp
index fb2bd1bb0c1e1ecb913856065ddad46c7501ef88..19ae7684bb316590a2847a961688a25c7fe48426 100644
--- a/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointWriter.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointWriter.cpp
@@ -31,12 +31,26 @@
 JfrCheckpointFlush::JfrCheckpointFlush(Type* old, size_t used, size_t requested, Thread* t) :
   _result(JfrCheckpointManager::flush(old, used, requested, t)) {}
 
-JfrCheckpointWriter::JfrCheckpointWriter(bool flushpoint, bool header, Thread* thread) :
-  JfrCheckpointWriterBase(JfrCheckpointManager::lease_buffer(thread), thread),
+JfrCheckpointWriter::JfrCheckpointWriter(JfrCheckpointType type /* GENERIC */) :
+  JfrCheckpointWriterBase(JfrCheckpointManager::lease_buffer(Thread::current()), Thread::current()),
   _time(JfrTicks::now()),
   _offset(0),
   _count(0),
-  _flushpoint(flushpoint),
+  _type(type),
+  _header(true) {
+  assert(this->is_acquired(), "invariant");
+  assert(0 == this->current_offset(), "invariant");
+  if (_header) {
+    reserve(sizeof(JfrCheckpointEntry));
+  }
+}
+
+JfrCheckpointWriter::JfrCheckpointWriter(Thread* t, bool header /* true */, JfrCheckpointType type /* GENERIC */) :
+  JfrCheckpointWriterBase(JfrCheckpointManager::lease_buffer(t), t),
+  _time(JfrTicks::now()),
+  _offset(0),
+  _count(0),
+  _type(type),
   _header(header) {
   assert(this->is_acquired(), "invariant");
   assert(0 == this->current_offset(), "invariant");
@@ -45,13 +59,27 @@ JfrCheckpointWriter::JfrCheckpointWriter(bool flushpoint, bool header, Thread* t
   }
 }
 
-static void write_checkpoint_header(u1* pos, jlong size, jlong time, bool flushpoint, juint type_count) {
+JfrCheckpointWriter::JfrCheckpointWriter(Thread* t, JfrBuffer* buffer, JfrCheckpointType type /* GENERIC */) :
+  JfrCheckpointWriterBase(buffer, t),
+  _time(JfrTicks::now()),
+  _offset(0),
+  _count(0),
+  _type(type),
+  _header(true) {
+  assert(this->is_acquired(), "invariant");
+  assert(0 == this->current_offset(), "invariant");
+  if (_header) {
+    reserve(sizeof(JfrCheckpointEntry));
+  }
+}
+
+static void write_checkpoint_header(u1* pos, int64_t size, jlong time, u4 checkpoint_type, u4 type_count) {
   assert(pos != NULL, "invariant");
   JfrBigEndianWriter be_writer(pos, sizeof(JfrCheckpointEntry));
   be_writer.write(size);
   be_writer.write(time);
   be_writer.write(JfrTicks::now().value() - time);
-  be_writer.write(flushpoint ? (juint)1 : (juint)0);
+  be_writer.write(checkpoint_type);
   be_writer.write(type_count);
   assert(be_writer.is_valid(), "invariant");
 }
@@ -74,18 +102,10 @@ JfrCheckpointWriter::~JfrCheckpointWriter() {
   assert(this->used_size() > sizeof(JfrCheckpointEntry), "invariant");
   const jlong size = this->current_offset();
   assert(size + this->start_pos() == this->current_pos(), "invariant");
-  write_checkpoint_header(const_cast<u1*>(this->start_pos()), size, _time, is_flushpoint(), count());
+  write_checkpoint_header(const_cast<u1*>(this->start_pos()), size, _time, (u4)_type, count());
   release();
 }
 
-void JfrCheckpointWriter::set_flushpoint(bool flushpoint) {
-  _flushpoint = flushpoint;
-}
-
-bool JfrCheckpointWriter::is_flushpoint() const {
-  return _flushpoint;
-}
-
 juint JfrCheckpointWriter::count() const {
   return _count;
 }
@@ -140,7 +160,7 @@ const u1* JfrCheckpointWriter::session_data(size_t* size, bool move /* false */,
   }
   *size = this->used_size();
   assert(this->start_pos() + *size == this->current_pos(), "invariant");
-  write_checkpoint_header(const_cast<u1*>(this->start_pos()), this->used_offset(), _time, is_flushpoint(), count());
+  write_checkpoint_header(const_cast<u1*>(this->start_pos()), this->used_offset(), _time, (u4)_type, count());
   _header = false; // the header was just written
   if (move) {
     this->seek(_offset);
diff --git a/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointWriter.hpp b/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointWriter.hpp
index efdfefd14732650f9a3d5b3f2cab03710c06438b..cd9754947ba2e3a57e321f18f87c7ce8dc6d8c60 100644
--- a/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointWriter.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/jfrCheckpointWriter.hpp
@@ -54,23 +54,24 @@ struct JfrCheckpointContext {
 };
 
 class JfrCheckpointWriter : public JfrCheckpointWriterBase {
+  friend class JfrCheckpointManager;
   friend class JfrSerializerRegistration;
  private:
   JfrTicks _time;
   jlong _offset;
   juint _count;
-  bool _flushpoint;
+  JfrCheckpointType _type;
   bool _header;
 
   juint count() const;
   void set_count(juint count);
   void increment();
-  void set_flushpoint(bool flushpoint);
-  bool is_flushpoint() const;
   const u1* session_data(size_t* size, bool move = false, const JfrCheckpointContext* ctx = NULL);
   void release();
+  JfrCheckpointWriter(Thread* t, JfrBuffer* buffer, JfrCheckpointType type = GENERIC);
  public:
-  JfrCheckpointWriter(bool flushpoint, bool header, Thread* thread);
+  JfrCheckpointWriter(JfrCheckpointType type = GENERIC);
+  JfrCheckpointWriter(Thread* t, bool header = true, JfrCheckpointType mode = GENERIC);
   ~JfrCheckpointWriter();
   void write_type(JfrTypeId type_id);
   void write_count(u4 nof_entries);
diff --git a/src/share/vm/jfr/recorder/checkpoint/jfrMetadataEvent.cpp b/src/share/vm/jfr/recorder/checkpoint/jfrMetadataEvent.cpp
index 6c4d72f4d6870a1130b7ff1e5cc852e6e9df3de4..6732f4e7e896d7a24eeede22aeba3a9537a2791f 100644
--- a/src/share/vm/jfr/recorder/checkpoint/jfrMetadataEvent.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/jfrMetadataEvent.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,61 +29,53 @@
 #include "oops/klass.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "oops/typeArrayOop.hpp"
-#include "runtime/semaphore.hpp"
 #include "runtime/thread.inline.hpp"
 
-static jbyteArray _metadata_blob = NULL;
-static Semaphore metadata_mutex_semaphore(1);
+static jbyteArray metadata_blob = NULL;
+static u8 metadata_id = 0;
+static u8 last_metadata_id = 0;
 
-void JfrMetadataEvent::lock() {
-  metadata_mutex_semaphore.wait();
+static void write_metadata_blob(JfrChunkWriter& chunkwriter) {
+  assert(metadata_blob != NULL, "invariant");
+  const typeArrayOop arr = (typeArrayOop)JfrJavaSupport::resolve_non_null(metadata_blob);
+  assert(arr != NULL, "invariant");
+  const int length = arr->length();
+  const Klass* const k = arr->klass();
+  assert(k != NULL && k->oop_is_array(), "invariant");
+  const TypeArrayKlass* const byte_arr_klass = TypeArrayKlass::cast((Klass*)k);
+  const jbyte* const data_address = arr->byte_at_addr(0);
+  chunkwriter.write_unbuffered(data_address, length);
 }
 
-void JfrMetadataEvent::unlock() {
-  metadata_mutex_semaphore.signal();
-}
-
-static void write_metadata_blob(JfrChunkWriter& chunkwriter, jbyteArray metadata_blob) {
-  if (metadata_blob != NULL) {
-    const typeArrayOop arr = (typeArrayOop)JfrJavaSupport::resolve_non_null(metadata_blob);
-    assert(arr != NULL, "invariant");
-    const int length = arr->length();
-    Klass* const k = arr->klass();
-    assert(k != NULL && k->oop_is_array(), "invariant");
-    const TypeArrayKlass* const byte_arr_klass = TypeArrayKlass::cast(k);
-    const jbyte* const data_address = arr->byte_at_addr(0);
-    chunkwriter.write_unbuffered(data_address, length);
-  }
-}
-
-// the semaphore is assumed to be locked  (was locked previous safepoint)
-size_t JfrMetadataEvent::write(JfrChunkWriter& chunkwriter, jlong metadata_offset) {
+void JfrMetadataEvent::write(JfrChunkWriter& chunkwriter) {
   assert(chunkwriter.is_valid(), "invariant");
-  assert(chunkwriter.current_offset() == metadata_offset, "invariant");
+  if (last_metadata_id == metadata_id && chunkwriter.has_metadata()) {
+    return;
+  }
   // header
-  chunkwriter.reserve(sizeof(u4));
+  const int64_t metadata_offset = chunkwriter.reserve(sizeof(u4));
   chunkwriter.write<u8>(EVENT_METADATA); // ID 0
   // time data
   chunkwriter.write(JfrTicks::now());
   chunkwriter.write((u8)0); // duration
-  chunkwriter.write((u8)0); // metadata id
-  write_metadata_blob(chunkwriter, _metadata_blob); // payload
-  unlock(); // open up for java to provide updated metadata
+  chunkwriter.write(metadata_id); // metadata id
+  write_metadata_blob(chunkwriter); // payload
   // fill in size of metadata descriptor event
-  const jlong size_written = chunkwriter.current_offset() - metadata_offset;
+  const int64_t size_written = chunkwriter.current_offset() - metadata_offset;
   chunkwriter.write_padded_at_offset((u4)size_written, metadata_offset);
-  return size_written;
+  chunkwriter.set_last_metadata_offset(metadata_offset);
+  last_metadata_id = metadata_id;
 }
 
 void JfrMetadataEvent::update(jbyteArray metadata) {
   JavaThread* thread = (JavaThread*)Thread::current();
   assert(thread->is_Java_thread(), "invariant");
   DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(thread));
-  lock();
-  if (_metadata_blob != NULL) {
-    JfrJavaSupport::destroy_global_jni_handle(_metadata_blob);
+  if (metadata_blob != NULL) {
+    JfrJavaSupport::destroy_global_jni_handle(metadata_blob);
   }
   const oop new_desc_oop = JfrJavaSupport::resolve_non_null(metadata);
-  _metadata_blob = new_desc_oop != NULL ? (jbyteArray)JfrJavaSupport::global_jni_handle(new_desc_oop, thread) : NULL;
-  unlock();
+  assert(new_desc_oop != NULL, "invariant");
+  metadata_blob = (jbyteArray)JfrJavaSupport::global_jni_handle(new_desc_oop, thread);
+  ++metadata_id;
 }
diff --git a/src/share/vm/jfr/recorder/checkpoint/jfrMetadataEvent.hpp b/src/share/vm/jfr/recorder/checkpoint/jfrMetadataEvent.hpp
index 09845069df63d942e1ef7adf8cccd96d24dfd482..15554c1d28002f801f0365b70ee2cb2e886ad0d2 100644
--- a/src/share/vm/jfr/recorder/checkpoint/jfrMetadataEvent.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/jfrMetadataEvent.hpp
@@ -33,13 +33,10 @@ class JfrChunkWriter;
 //
 // Metadata is continuously updated in Java as event classes are loaded / unloaded.
 // Using update(), Java stores a binary representation back to native.
-// This is for easy access on chunk finalization as well as having it readily available in the case of fatal error.
 //
 class JfrMetadataEvent : AllStatic {
  public:
-  static void lock();
-  static void unlock();
-  static size_t write(JfrChunkWriter& writer, jlong metadata_offset);
+  static void write(JfrChunkWriter& writer);
   static void update(jbyteArray metadata);
 };
 
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadGroup.cpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadGroup.cpp
index d090a1891dbbb3158050e25b2dea22386ea10ef2..048757afbd169b9a8111d3d08c54ea79ed5581c8 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadGroup.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadGroup.cpp
@@ -25,7 +25,6 @@
 #include "precompiled.hpp"
 #include "jfr/recorder/checkpoint/jfrCheckpointWriter.hpp"
 #include "jfr/recorder/checkpoint/types/jfrThreadGroup.hpp"
-#include "jfr/utilities/jfrResourceManager.hpp"
 #include "jfr/utilities/jfrTypes.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/jniHandles.hpp"
@@ -33,6 +32,8 @@
 #include "runtime/semaphore.hpp"
 #include "utilities/growableArray.hpp"
 
+static const int initial_array_size = 30;
+
 class ThreadGroupExclusiveAccess : public StackObj {
  private:
   static Semaphore _mutex_semaphore;
@@ -257,12 +258,10 @@ void JfrThreadGroup::JfrThreadGroupEntry::set_thread_group(JfrThreadGroupPointer
   }
 }
 
-JfrThreadGroup::JfrThreadGroup() : _list(NULL) {
-  _list = new (ResourceObj::C_HEAP, mtTracing) GrowableArray<JfrThreadGroupEntry*>(30, true);
-}
+JfrThreadGroup::JfrThreadGroup() :
+  _list(new (ResourceObj::C_HEAP, mtTracing) GrowableArray<JfrThreadGroupEntry*>(initial_array_size, true, mtTracing)) {}
 
 JfrThreadGroup::~JfrThreadGroup() {
-  assert(SafepointSynchronize::is_at_safepoint(), "invariant");
   if (_list != NULL) {
     for (int i = 0; i < _list->length(); i++) {
       JfrThreadGroupEntry* e = _list->at(i);
@@ -281,14 +280,11 @@ void JfrThreadGroup::set_instance(JfrThreadGroup* new_instance) {
 }
 
 traceid JfrThreadGroup::thread_group_id(const JavaThread* jt, Thread* current) {
-  ResourceMark rm(current);
-  HandleMark hm(current);
   JfrThreadGroupsHelper helper(jt, current);
   return helper.is_valid() ? thread_group_id_internal(helper) : 0;
 }
 
 traceid JfrThreadGroup::thread_group_id(JavaThread* jt) {
-  assert(!JfrStream_lock->owned_by_self(), "holding stream lock but should not hold it here");
   return thread_group_id(jt, jt);
 }
 
@@ -398,9 +394,7 @@ void JfrThreadGroup::serialize(JfrCheckpointWriter& writer) {
   ThreadGroupExclusiveAccess lock;
   JfrThreadGroup* tg_instance = instance();
   assert(tg_instance != NULL, "invariant");
-  ResourceManager<JfrThreadGroup> tg_handle(tg_instance);
-  set_instance(NULL);
-  tg_handle->write_thread_group_entries(writer);
+  tg_instance->write_thread_group_entries(writer);
 }
 
 // for writing a particular thread group
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadState.cpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadState.cpp
index 50e213b3ce5d3ae10a274b4a78be5a3556f4e36a..31b2416d2b9c65861d505b8e82c3c7552f609360 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadState.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadState.cpp
@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+* Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
@@ -23,9 +23,13 @@
 */
 
 #include "precompiled.hpp"
+#include "classfile/javaClasses.hpp"
 #include "jfr/recorder/checkpoint/types/jfrThreadState.hpp"
 #include "jfr/recorder/checkpoint/jfrCheckpointWriter.hpp"
+#include "jfr/support/jfrThreadLocal.hpp"
 #include "jvmtifiles/jvmti.h"
+#include "runtime/osThread.hpp"
+#include "runtime/thread.hpp"
 
 struct jvmti_thread_state {
   u8 id;
@@ -80,3 +84,47 @@ void JfrThreadState::serialize(JfrCheckpointWriter& writer) {
   }
 }
 
+traceid JfrThreadId::id(const Thread* t) {
+  assert(t != NULL, "invariant");
+  if (!t->is_Java_thread()) {
+    return os_id(t);
+  }
+  const JavaThread* const jt = (JavaThread*)t;
+  const oop thread_obj = jt->threadObj();
+  return thread_obj != NULL ? java_lang_Thread::thread_id(thread_obj) : 0;
+}
+
+traceid JfrThreadId::os_id(const Thread* t) {
+  assert(t != NULL, "invariant");
+  const OSThread* const os_thread = t->osthread();
+  return os_thread != NULL ? os_thread->thread_id() : 0;
+}
+
+traceid JfrThreadId::jfr_id(const Thread* t) {
+  assert(t != NULL, "invariant");
+  return t->jfr_thread_local()->thread_id();
+}
+
+// caller needs ResourceMark
+const char* get_java_thread_name(const Thread* t) {
+  assert(t != NULL, "invariant");
+  assert(t->is_Java_thread(), "invariant");
+  const JavaThread* const jt = ((JavaThread*)t);
+  const char* name_str = "<no-name - thread name unresolved>";
+  const oop thread_obj = jt->threadObj();
+  if (thread_obj != NULL) {
+    const oop name = java_lang_Thread::name(thread_obj);
+    if (name != NULL) {
+      name_str = java_lang_String::as_utf8_string(name);
+    }
+  } else if (jt->is_attaching_via_jni()) {
+    name_str = "<no-name - thread is attaching>";
+  }
+  assert(name_str != NULL, "unexpected NULL thread name");
+  return name_str;
+}
+
+const char* JfrThreadName::name(const Thread* t) {
+  assert(t != NULL, "invariant");
+  return t->is_Java_thread() ? get_java_thread_name(t) : t->name();
+}
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadState.hpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadState.hpp
index bcedaa7949e082c9521785268977ce71c4644483..9fd241193053d56fb017a1f8a7599568fc6c74cc 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadState.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrThreadState.hpp
@@ -28,10 +28,24 @@
 #include "memory/allocation.hpp"
 
 class JfrCheckpointWriter;
+class Thread;
 
 class JfrThreadState : public AllStatic {
  public:
   static void serialize(JfrCheckpointWriter& writer);
 };
 
+class JfrThreadId : public AllStatic {
+public:
+  static traceid id(const Thread* t);
+  static traceid os_id(const Thread* t);
+  static traceid jfr_id(const Thread* t);
+};
+
+class JfrThreadName : public AllStatic {
+ public:
+  // Requires a ResourceMark for get_thread_name/as_utf8
+  static const char* name(const Thread* t);
+};
+
 #endif // SHARE_VM_JFR_RECORDER_CHECKPOINT_TYPES_JFRTHREADSTATE_HPP
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrType.cpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrType.cpp
index f717ae6fbf66b4ce19a35aa308f739d32166aca6..2079fcb28c0c2ccef3bb6a34aa22040221545781 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrType.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrType.cpp
@@ -31,13 +31,14 @@
 #include "gc_implementation/shared/gcTrace.hpp"
 #include "gc_implementation/shared/gcWhen.hpp"
 #include "jfr/leakprofiler/leakProfiler.hpp"
-#include "jfr/recorder/checkpoint/jfrCheckpointManager.hpp"
+#include "jfr/recorder/checkpoint/jfrCheckpointWriter.hpp"
 #include "jfr/recorder/checkpoint/types/jfrType.hpp"
 #include "jfr/recorder/jfrRecorder.hpp"
 #include "jfr/recorder/checkpoint/types/jfrThreadGroup.hpp"
 #include "jfr/recorder/checkpoint/types/jfrThreadState.hpp"
 #include "jfr/support/jfrThreadLocal.hpp"
 #include "jfr/writers/jfrJavaEventWriter.hpp"
+#include "jfr/utilities/jfrThreadIterator.hpp"
 #include "memory/metaspaceGCThresholdUpdater.hpp"
 #include "memory/referenceType.hpp"
 #include "memory/universe.hpp"
@@ -86,27 +87,18 @@ class JfrCheckpointThreadClosure : public ThreadClosure {
   void do_thread(Thread* t);
 };
 
-// Requires a ResourceMark for get_thread_name/as_utf8
 void JfrCheckpointThreadClosure::do_thread(Thread* t) {
   assert(t != NULL, "invariant");
-  assert_locked_or_safepoint(Threads_lock);
-  const JfrThreadLocal* const tl = t->jfr_thread_local();
-  assert(tl != NULL, "invariant");
-  if (tl->is_dead()) {
-    return;
-  }
   ++_count;
-  _writer.write_key(tl->thread_id());
-  _writer.write(t->name());
-  const OSThread* const os_thread = t->osthread();
-  _writer.write<traceid>(os_thread != NULL ? os_thread->thread_id() : 0);
+  _writer.write_key(JfrThreadId::jfr_id(t));
+  const char* const name = JfrThreadName::name(t);
+  assert(name != NULL, "invariant");
+  _writer.write(name);
+  _writer.write<traceid>(JfrThreadId::os_id(t));
   if (t->is_Java_thread()) {
-    JavaThread* const jt = (JavaThread*)t;
-    _writer.write(jt->name());
-    _writer.write(java_lang_Thread::thread_id(jt->threadObj()));
-    _writer.write(JfrThreadGroup::thread_group_id(jt, _curthread));
-    // since we are iterating threads during a safepoint, also issue notification
-    JfrJavaEventWriter::notify(jt);
+    _writer.write(name);
+    _writer.write(JfrThreadId::id(t));
+    _writer.write(JfrThreadGroup::thread_group_id((JavaThread*)t, _curthread));
     return;
   }
   _writer.write((const char*)NULL); // java name
@@ -115,13 +107,18 @@ void JfrCheckpointThreadClosure::do_thread(Thread* t) {
 }
 
 void JfrThreadConstantSet::serialize(JfrCheckpointWriter& writer) {
-  assert(SafepointSynchronize::is_at_safepoint(), "invariant");
   JfrCheckpointThreadClosure tc(writer);
-  Threads::threads_do(&tc);
+  JfrJavaThreadIterator javathreads;
+  while (javathreads.has_next()) {
+    tc.do_thread(javathreads.next());
+  }
+  JfrNonJavaThreadIterator nonjavathreads;
+  while (nonjavathreads.has_next()) {
+    tc.do_thread(nonjavathreads.next());
+  }
 }
 
 void JfrThreadGroupConstant::serialize(JfrCheckpointWriter& writer) {
-  assert(SafepointSynchronize::is_at_safepoint(), "invariant");
   JfrThreadGroup::serialize(writer);
 }
 
@@ -298,19 +295,21 @@ void ThreadStateConstant::serialize(JfrCheckpointWriter& writer) {
 void JfrThreadConstant::serialize(JfrCheckpointWriter& writer) {
   assert(_thread != NULL, "invariant");
   assert(_thread == Thread::current(), "invariant");
-  assert(_thread->is_Java_thread(), "invariant");
-  ResourceMark rm(_thread);
-  const oop threadObj = _thread->threadObj();
-  assert(threadObj != NULL, "invariant");
-  const u8 java_lang_thread_id = java_lang_Thread::thread_id(threadObj);
-  const char* const thread_name = _thread->name();
-  const traceid thread_group_id = JfrThreadGroup::thread_group_id(_thread);
   writer.write_count(1);
-  writer.write_key(_thread->jfr_thread_local()->thread_id());
-  writer.write(thread_name);
-  writer.write((traceid)_thread->osthread()->thread_id());
-  writer.write(thread_name);
-  writer.write(java_lang_thread_id);
-  writer.write(thread_group_id);
-  JfrThreadGroup::serialize(&writer, thread_group_id);
+  writer.write_key(JfrThreadId::jfr_id(_thread));
+  const char* const name = JfrThreadName::name(_thread);
+  writer.write(name);
+  writer.write(JfrThreadId::os_id(_thread));
+  if (_thread->is_Java_thread()) {
+    writer.write(name);
+    writer.write(JfrThreadId::id(_thread));
+    JavaThread* const jt = (JavaThread*)_thread;
+    const traceid thread_group_id = JfrThreadGroup::thread_group_id(jt, jt);
+    writer.write(thread_group_id);
+    JfrThreadGroup::serialize(&writer, thread_group_id);
+    return;
+  }
+  writer.write((const char*)NULL); // java name
+  writer.write((traceid)0); // java thread id
+  writer.write((traceid)0); // java thread group
 }
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrType.hpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrType.hpp
index cddbc43aaa31ec2b2f21db2ea4abe0e10038286a..b13720ec9e98379e7eeaa427a01d670965d18331 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrType.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrType.hpp
@@ -27,16 +27,6 @@
 
 #include "jfr/metadata/jfrSerializer.hpp"
 
-class JfrThreadConstantSet : public JfrSerializer {
- public:
-  void serialize(JfrCheckpointWriter& writer);
-};
-
-class JfrThreadGroupConstant : public JfrSerializer {
- public:
-  void serialize(JfrCheckpointWriter& writer);
-};
-
 class FlagValueOriginConstant : public JfrSerializer {
  public:
   void serialize(JfrCheckpointWriter& writer);
@@ -112,6 +102,16 @@ class VMOperationTypeConstant : public JfrSerializer {
   void serialize(JfrCheckpointWriter& writer);
 };
 
+class JfrThreadConstantSet : public JfrSerializer {
+ public:
+  void serialize(JfrCheckpointWriter& writer);
+};
+
+class JfrThreadGroupConstant : public JfrSerializer {
+ public:
+  void serialize(JfrCheckpointWriter& writer);
+};
+
 class ThreadStateConstant : public JfrSerializer {
  public:
   void serialize(JfrCheckpointWriter& writer);
@@ -119,9 +119,9 @@ class ThreadStateConstant : public JfrSerializer {
 
 class JfrThreadConstant : public JfrSerializer {
  private:
-  JavaThread* _thread;
+  Thread* _thread;
  public:
-  JfrThreadConstant(JavaThread* jt) : _thread(jt) {}
+  JfrThreadConstant(Thread* t) : _thread(t) {}
   void serialize(JfrCheckpointWriter& writer);
 };
 
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeManager.cpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeManager.cpp
index 135491dd986a36dac8e4e37f758f6e4f333c3a57..84d02cb27a6f2bd0603161efc9ad454eb7e25b26 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeManager.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeManager.cpp
@@ -27,6 +27,7 @@
 #include "jfr/recorder/checkpoint/jfrCheckpointWriter.hpp"
 #include "jfr/recorder/checkpoint/types/jfrType.hpp"
 #include "jfr/recorder/checkpoint/types/jfrTypeManager.hpp"
+#include "jfr/recorder/jfrRecorder.hpp"
 #include "jfr/utilities/jfrDoublyLinkedList.hpp"
 #include "jfr/utilities/jfrIterator.hpp"
 #include "memory/resourceArea.hpp"
@@ -73,29 +74,71 @@ class JfrSerializerRegistration : public JfrCHeapObj {
     return _id;
   }
 
-  void invoke(JfrCheckpointWriter& writer) const;
+  void on_rotation() const {
+    _serializer->on_rotation();
+  }
+
+  void invoke(JfrCheckpointWriter& writer) const {
+    if (_cache.valid()) {
+      writer.increment();
+      _cache->write(writer);
+      return;
+    }
+    const JfrCheckpointContext ctx = writer.context();
+    // serialize the type id before invoking callback
+    writer.write_type(_id);
+    const intptr_t start = writer.current_offset();
+    // invoke the serializer routine
+    _serializer->serialize(writer);
+    if (start == writer.current_offset()) {
+      // the serializer implementation did nothing, rewind to restore
+      writer.set_context(ctx);
+      return;
+    }
+    if (_permit_cache) {
+      _cache = writer.copy(&ctx);
+    }
+  }
 };
 
-void JfrSerializerRegistration::invoke(JfrCheckpointWriter& writer) const {
-  if (_cache.valid()) {
-    writer.increment();
-    _cache->write(writer);
-    return;
-  }
-  const JfrCheckpointContext ctx = writer.context();
-  // serialize the type id before invoking callback
-  writer.write_type(_id);
-  const intptr_t start = writer.current_offset();
-  // invoke the serializer routine
-  _serializer->serialize(writer);
-  if (start == writer.current_offset() ) {
-    // the serializer implementation did nothing, rewind to restore
-    writer.set_context(ctx);
-    return;
-  }
-  if (_permit_cache) {
-    _cache = writer.copy(&ctx);
-  }
+static void serialize_threads(JfrCheckpointWriter& writer) {
+  JfrThreadConstantSet thread_set;
+  writer.write_type(TYPE_THREAD);
+  thread_set.serialize(writer);
+}
+
+static void serialize_thread_groups(JfrCheckpointWriter& writer) {
+  JfrThreadGroupConstant thread_group_set;
+  writer.write_type(TYPE_THREADGROUP);
+  thread_group_set.serialize(writer);
+}
+
+void JfrTypeManager::write_threads(JfrCheckpointWriter& writer) {
+  serialize_threads(writer);
+  serialize_thread_groups(writer);
+}
+
+void JfrTypeManager::create_thread_blob(Thread* t) {
+  assert(t != NULL, "invariant");
+  ResourceMark rm(t);
+  HandleMark hm(t);
+  JfrThreadConstant type_thread(t);
+  JfrCheckpointWriter writer(t, true, THREADS);
+  writer.write_type(TYPE_THREAD);
+  type_thread.serialize(writer);
+  // create and install a checkpoint blob
+  t->jfr_thread_local()->set_thread_blob(writer.move());
+  assert(t->jfr_thread_local()->has_thread_blob(), "invariant");
+}
+
+void JfrTypeManager::write_thread_checkpoint(Thread* t) {
+  assert(t != NULL, "invariant");
+  ResourceMark rm(t);
+  HandleMark hm(t);
+  JfrThreadConstant type_thread(t);
+  JfrCheckpointWriter writer(t, true, THREADS);
+  writer.write_type(TYPE_THREAD);
+  type_thread.serialize(writer);
 }
 
 class SerializerRegistrationGuard : public StackObj {
@@ -115,7 +158,6 @@ Semaphore SerializerRegistrationGuard::_mutex_semaphore(1);
 typedef JfrDoublyLinkedList<JfrSerializerRegistration> List;
 typedef StopOnNullIterator<const List> Iterator;
 static List types;
-static List safepoint_types;
 
 void JfrTypeManager::destroy() {
   SerializerRegistrationGuard guard;
@@ -126,52 +168,15 @@ void JfrTypeManager::destroy() {
     assert(registration != NULL, "invariant");
     delete registration;
   }
-  Iterator sp_type_iter(safepoint_types);
-  while (sp_type_iter.has_next()) {
-    registration = safepoint_types.remove(sp_type_iter.next());
-    assert(registration != NULL, "invariant");
-    delete registration;
-  }
 }
 
-void JfrTypeManager::write_types(JfrCheckpointWriter& writer) {
+void JfrTypeManager::on_rotation() {
   const Iterator iter(types);
   while (iter.has_next()) {
-    iter.next()->invoke(writer);
-  }
-}
-
-void JfrTypeManager::write_safepoint_types(JfrCheckpointWriter& writer) {
-  assert(SafepointSynchronize::is_at_safepoint(), "invariant");
-  const Iterator iter(safepoint_types);
-  while (iter.has_next()) {
-    iter.next()->invoke(writer);
+    iter.next()->on_rotation();
   }
 }
 
-void JfrTypeManager::create_thread_blob(JavaThread* jt) {
-  assert(jt != NULL, "invariant");
-  ResourceMark rm(jt);
-  HandleMark hm(jt);
-  JfrThreadConstant type_thread(jt);
-  JfrCheckpointWriter writer(false, true, jt);
-  writer.write_type(TYPE_THREAD);
-  type_thread.serialize(writer);
-  // create and install a checkpoint blob
-  jt->jfr_thread_local()->set_thread_blob(writer.move());
-  assert(jt->jfr_thread_local()->has_thread_blob(), "invariant");
-}
-
-void JfrTypeManager::write_thread_checkpoint(JavaThread* jt) {
-  assert(jt != NULL, "JavaThread is NULL!");
-  ResourceMark rm(jt);
-  HandleMark hm(jt);
-  JfrThreadConstant type_thread(jt);
-  JfrCheckpointWriter writer(false, true, jt);
-  writer.write_type(TYPE_THREAD);
-  type_thread.serialize(writer);
-}
-
 #ifdef ASSERT
 static void assert_not_registered_twice(JfrTypeId id, List& list) {
   const Iterator iter(list);
@@ -181,22 +186,23 @@ static void assert_not_registered_twice(JfrTypeId id, List& list) {
 }
 #endif
 
-static bool register_type(JfrTypeId id, bool require_safepoint, bool permit_cache, JfrSerializer* serializer) {
+static bool new_registration = false;
+
+static bool register_static_type(JfrTypeId id, bool permit_cache, JfrSerializer* serializer) {
   assert(serializer != NULL, "invariant");
   JfrSerializerRegistration* const registration = new JfrSerializerRegistration(id, permit_cache, serializer);
   if (registration == NULL) {
     delete serializer;
     return false;
   }
-  if (require_safepoint) {
-    assert(!safepoint_types.in_list(registration), "invariant");
-    DEBUG_ONLY(assert_not_registered_twice(id, safepoint_types);)
-    safepoint_types.prepend(registration);
-  } else {
-    assert(!types.in_list(registration), "invariant");
-    DEBUG_ONLY(assert_not_registered_twice(id, types);)
-    types.prepend(registration);
+  assert(!types.in_list(registration), "invariant");
+  DEBUG_ONLY(assert_not_registered_twice(id, types);)
+  if (JfrRecorder::is_recording()) {
+    JfrCheckpointWriter writer(STATICS);
+    registration->invoke(writer);
+    new_registration = true;
   }
+  types.prepend(registration);
   return true;
 }
 
@@ -204,31 +210,46 @@ bool JfrTypeManager::initialize() {
   SerializerRegistrationGuard guard;
 
   // register non-safepointing type serialization
-  register_type(TYPE_FLAGVALUEORIGIN, false, true, new FlagValueOriginConstant());
-  register_type(TYPE_INFLATECAUSE, false, true, new MonitorInflateCauseConstant());
-  register_type(TYPE_GCCAUSE, false, true, new GCCauseConstant());
-  register_type(TYPE_GCNAME, false, true, new GCNameConstant());
-  register_type(TYPE_GCWHEN, false, true, new GCWhenConstant());
-  register_type(TYPE_G1HEAPREGIONTYPE, false, true, new G1HeapRegionTypeConstant());
-  register_type(TYPE_GCTHRESHOLDUPDATER, false, true, new GCThresholdUpdaterConstant());
-  register_type(TYPE_METADATATYPE, false, true, new MetadataTypeConstant());
-  register_type(TYPE_METASPACEOBJECTTYPE, false, true, new MetaspaceObjectTypeConstant());
-  register_type(TYPE_G1YCTYPE, false, true, new G1YCTypeConstant());
-  register_type(TYPE_REFERENCETYPE, false, true, new ReferenceTypeConstant());
-  register_type(TYPE_NARROWOOPMODE, false, true, new NarrowOopModeConstant());
-  register_type(TYPE_COMPILERPHASETYPE, false, true, new CompilerPhaseTypeConstant());
-  register_type(TYPE_CODEBLOBTYPE, false, true, new CodeBlobTypeConstant());
-  register_type(TYPE_VMOPERATIONTYPE, false, true, new VMOperationTypeConstant());
-  register_type(TYPE_THREADSTATE, false, true, new ThreadStateConstant());
-
-  // register safepointing type serialization
-  register_type(TYPE_THREADGROUP, true, false, new JfrThreadGroupConstant());
-  register_type(TYPE_THREAD, true, false, new JfrThreadConstantSet());
+  register_static_type(TYPE_FLAGVALUEORIGIN, true, new FlagValueOriginConstant());
+  register_static_type(TYPE_INFLATECAUSE, true, new MonitorInflateCauseConstant());
+  register_static_type(TYPE_GCCAUSE, true, new GCCauseConstant());
+  register_static_type(TYPE_GCNAME, true, new GCNameConstant());
+  register_static_type(TYPE_GCWHEN, true, new GCWhenConstant());
+  register_static_type(TYPE_G1HEAPREGIONTYPE, true, new G1HeapRegionTypeConstant());
+  register_static_type(TYPE_GCTHRESHOLDUPDATER, true, new GCThresholdUpdaterConstant());
+  register_static_type(TYPE_METADATATYPE, true, new MetadataTypeConstant());
+  register_static_type(TYPE_METASPACEOBJECTTYPE, true, new MetaspaceObjectTypeConstant());
+  register_static_type(TYPE_G1YCTYPE, true, new G1YCTypeConstant());
+  register_static_type(TYPE_REFERENCETYPE, true, new ReferenceTypeConstant());
+  register_static_type(TYPE_NARROWOOPMODE, true, new NarrowOopModeConstant());
+  register_static_type(TYPE_COMPILERPHASETYPE, true, new CompilerPhaseTypeConstant());
+  register_static_type(TYPE_CODEBLOBTYPE, true, new CodeBlobTypeConstant());
+  register_static_type(TYPE_VMOPERATIONTYPE, true, new VMOperationTypeConstant());
+  register_static_type(TYPE_THREADSTATE, true, new ThreadStateConstant());
+
   return true;
 }
 
 // implementation for the static registration function exposed in the JfrSerializer api
-bool JfrSerializer::register_serializer(JfrTypeId id, bool require_safepoint, bool permit_cache, JfrSerializer* serializer) {
+bool JfrSerializer::register_serializer(JfrTypeId id, bool permit_cache, JfrSerializer* serializer) {
   SerializerRegistrationGuard guard;
-  return register_type(id, require_safepoint, permit_cache, serializer);
+  return register_static_type(id, permit_cache, serializer);
+}
+
+bool JfrTypeManager::has_new_static_type() {
+  if (new_registration) {
+    SerializerRegistrationGuard guard;
+    new_registration = false;
+    return true;
+  }
+  return false;
+}
+
+void JfrTypeManager::write_static_types(JfrCheckpointWriter& writer) {
+  SerializerRegistrationGuard guard;
+  const Iterator iter(types);
+  while (iter.has_next()) {
+    iter.next()->invoke(writer);
+  }
+  new_registration = false;
 }
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeManager.hpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeManager.hpp
index 50b01024bebe771bb68bd0f455518ceeb1f10af7..0f2aa2bcd1379feae56c69cd40b671f6a5197360 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeManager.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeManager.hpp
@@ -33,10 +33,12 @@ class JfrTypeManager : public AllStatic {
  public:
   static bool initialize();
   static void destroy();
-  static void write_types(JfrCheckpointWriter& writer);
-  static void write_safepoint_types(JfrCheckpointWriter& writer);
-  static void create_thread_blob(JavaThread* jt);
-  static void write_thread_checkpoint(JavaThread* jt);
+  static void on_rotation();
+  static void write_threads(JfrCheckpointWriter& writer);
+  static void create_thread_blob(Thread* t);
+  static void write_thread_checkpoint(Thread* t);
+  static bool has_new_static_type();
+  static void write_static_types(JfrCheckpointWriter& writer);
 };
 
 #endif // SHARE_VM_JFR_CHECKPOINT_TYPES_JFRTYPEMANAGER_HPP
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.cpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.cpp
index ac88cda0553c0dcc23f1b4f7c7b8cea95a971cb1..d9ee53cd035d41ac121dc479b5060b19780d910a 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.cpp
@@ -72,7 +72,7 @@ static traceid create_symbol_id(traceid artifact_id) {
 }
 
 static bool current_epoch() {
-  return _class_unload;
+  return _class_unload || _flushpoint;
 }
 
 static bool previous_epoch() {
@@ -109,14 +109,14 @@ inline uintptr_t package_name_hash(const char *s) {
   return val;
 }
 
-static traceid package_id(KlassPtr klass, JfrArtifactSet* artifacts) {
+static traceid package_id(KlassPtr klass, JfrArtifactSet* artifacts, bool leakp) {
   assert(klass != NULL, "invariant");
   char* klass_name = klass->name()->as_C_string(); // uses ResourceMark declared in JfrTypeSet::serialize()
   const char* pkg_name = ClassLoader::package_from_name(klass_name, NULL);
   if (pkg_name == NULL) {
     return 0;
   }
-  return CREATE_PACKAGE_ID(artifacts->markPackage(pkg_name, package_name_hash(pkg_name)));
+  return CREATE_PACKAGE_ID(artifacts->markPackage(pkg_name, package_name_hash(pkg_name), leakp));
 }
 
 static traceid method_id(KlassPtr klass, MethodPtr method) {
@@ -178,7 +178,7 @@ static int write_klass(JfrCheckpointWriter* writer, KlassPtr klass, bool leakp)
     theklass = obj_arr_klass->bottom_klass();
   }
   if (theklass->oop_is_instance()) {
-    pkg_id = package_id(theklass, _artifacts);
+    pkg_id = package_id(theklass, _artifacts, leakp);
   } else {
     assert(theklass->oop_is_typeArray(), "invariant");
   }
@@ -245,7 +245,7 @@ static void do_unloaded_klass(Klass* klass) {
 static void do_klass(Klass* klass) {
   assert(klass != NULL, "invariant");
   assert(_subsystem_callback != NULL, "invariant");
-  if (current_epoch()) {
+  if (_flushpoint) {
     if (USED_THIS_EPOCH(klass)) {
       _subsystem_callback->do_artifact(klass);
       return;
@@ -316,7 +316,14 @@ static bool write_klasses() {
   return true;
 }
 
-int write__artifact__package(JfrCheckpointWriter* writer, const void* p) {
+template <>
+void set_serialized<JfrSymbolId::CStringEntry>(CStringEntryPtr ptr) {
+  assert(ptr != NULL, "invariant");
+  ptr->set_serialized();
+  assert(ptr->is_serialized(), "invariant");
+}
+
+int write__package(JfrCheckpointWriter* writer, const void* p) {
   assert(writer != NULL, "invariant");
   assert(_artifacts != NULL, "invariant");
   assert(p != NULL, "invariant");
@@ -327,17 +334,45 @@ int write__artifact__package(JfrCheckpointWriter* writer, const void* p) {
   writer->write((traceid)CREATE_PACKAGE_ID(entry->id()));
   writer->write((traceid)CREATE_SYMBOL_ID(package_name_symbol_id));
   writer->write((bool)true); // exported
+  set_serialized(entry);
+  return 1;
+}
+
+int write__package__leakp(JfrCheckpointWriter* writer, const void* p) {
+  assert(writer != NULL, "invariant");
+  assert(_artifacts != NULL, "invariant");
+  assert(p != NULL, "invariant");
+
+  CStringEntryPtr entry = (CStringEntryPtr)p;
+  const traceid package_name_symbol_id = _artifacts->mark(package_name_hash(entry->value()), entry->value(), true);
+  assert(package_name_symbol_id > 0, "invariant");
+  writer->write((traceid)CREATE_PACKAGE_ID(entry->id()));
+  writer->write((traceid)CREATE_SYMBOL_ID(package_name_symbol_id));
+  writer->write((bool)true); // exported
   return 1;
 }
 
-typedef JfrTypeWriterImplHost<CStringEntryPtr, write__artifact__package> PackageEntryWriterImpl;
-typedef JfrTypeWriterHost<PackageEntryWriterImpl, TYPE_PACKAGE> PackageEntryWriter;
+typedef SymbolPredicate<CStringEntryPtr, false> PackageCStringPredicate;
+typedef JfrPredicatedTypeWriterImplHost<CStringEntryPtr, PackageCStringPredicate, write__package> PackageCStringEntryWriterImpl;
+typedef JfrTypeWriterHost<PackageCStringEntryWriterImpl, TYPE_PACKAGE> PackageCStringEntryWriter;
+
+typedef SymbolPredicate<CStringEntryPtr, true> LeakPackageCStringPredicate;
+typedef JfrPredicatedTypeWriterImplHost<CStringEntryPtr, LeakPackageCStringPredicate, write__package__leakp> LeakPackageCStringEntryWriterImpl;
+typedef JfrTypeWriterHost<LeakPackageCStringEntryWriterImpl, TYPE_PACKAGE> LeakPackageCStringEntryWriter;
+typedef CompositeFunctor<CStringEntryPtr, LeakPackageCStringEntryWriter, PackageCStringEntryWriter> CompositePackageCStringWriter;
 
 void write_packages() {
-  // below jdk9 there is no oop for packages, so nothing to do with leakp_writer
-  // just write packages
-  PackageEntryWriter pw(_writer, _class_unload);
-  _artifacts->iterate_packages(pw);
+  if (_leakp_writer != NULL) {
+    PackageCStringEntryWriter pcsw(_writer, _class_unload);
+    LeakPackageCStringEntryWriter lpcsw(_leakp_writer, _class_unload);
+    CompositePackageCStringWriter cpcsw(&lpcsw, &pcsw);
+    _artifacts->iterate_packages(cpcsw);
+    _artifacts->tally(pcsw);
+  } else {
+    PackageCStringEntryWriter pcsw(_writer, _class_unload);
+    _artifacts->iterate_packages(pcsw);
+    _artifacts->tally(pcsw);
+  }
 }
 
 template <typename T>
@@ -636,13 +671,6 @@ void set_serialized<JfrSymbolId::SymbolEntry>(SymbolEntryPtr ptr) {
   assert(ptr->is_serialized(), "invariant");
 }
 
-template <>
-void set_serialized<JfrSymbolId::CStringEntry>(CStringEntryPtr ptr) {
-  assert(ptr != NULL, "invariant");
-  ptr->set_serialized();
-  assert(ptr->is_serialized(), "invariant");
-}
-
 static int write_symbol(JfrCheckpointWriter* writer, SymbolEntryPtr entry, bool leakp) {
   assert(writer != NULL, "invariant");
   assert(entry != NULL, "invariant");
@@ -754,10 +782,11 @@ static size_t teardown() {
   return total_count;
 }
 
-static void setup(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer, bool class_unload) {
+static void setup(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer, bool class_unload, bool flushpoint) {
   _writer = writer;
   _leakp_writer = leakp_writer;
   _class_unload = class_unload;
+  _flushpoint = flushpoint;
   if (_artifacts == NULL) {
     _artifacts = new JfrArtifactSet(class_unload);
   } else {
@@ -771,10 +800,10 @@ static void setup(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer
 /**
  * Write all "tagged" (in-use) constant artifacts and their dependencies.
  */
-size_t JfrTypeSet::serialize(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer, bool class_unload) {
+size_t JfrTypeSet::serialize(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer, bool class_unload, bool flushpoint) {
   assert(writer != NULL, "invariant");
   ResourceMark rm;
-  setup(writer, leakp_writer, class_unload);
+  setup(writer, leakp_writer, class_unload, flushpoint);
   // write order is important because an individual write step
   // might tag an artifact to be written in a subsequent step
   if (!write_klasses()) {
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.hpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.hpp
index 949380271f74eb5c47e2d6d9cd64560e9ca6b0a0..4d097d731fe4b18909e18e6d1b69a77865cc0cfb 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.hpp
@@ -32,7 +32,7 @@ class JfrCheckpointWriter;
 class JfrTypeSet : AllStatic {
  public:
   static void clear();
-  static size_t serialize(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer, bool class_unload);
+  static size_t serialize(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer, bool class_unload, bool flushpoint);
 };
 
 #endif // SHARE_VM_JFR_RECORDER_CHECKPOINT_TYPES_JFRTYPESET_HPP
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSetUtils.cpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSetUtils.cpp
index 4e0318d2c43947f5e3e883dcc43c58902f9e7cb4..4c122ed613e2564a92ee8a124a2dce8079a59c8a 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSetUtils.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSetUtils.cpp
@@ -175,7 +175,7 @@ traceid JfrSymbolId::mark(uintptr_t hash, const Symbol* data, bool leakp) {
   return entry.id();
 }
 
-traceid JfrSymbolId::markPackage(const char* name, uintptr_t hash) {
+traceid JfrSymbolId::markPackage(const char* name, uintptr_t hash, bool leakp) {
   assert(name != NULL, "invariant");
   assert(_pkg_table != NULL, "invariant");
   _cstring_query = name;
@@ -183,6 +183,9 @@ traceid JfrSymbolId::markPackage(const char* name, uintptr_t hash) {
   if (_class_unload) {
     entry.set_unloading();
   }
+  if (leakp) {
+    entry.set_leakp();
+  }
   return entry.id();
 }
 
@@ -308,8 +311,8 @@ traceid JfrArtifactSet::mark(const Klass* klass, bool leakp) {
   return _symbol_id->mark(klass, leakp);
 }
 
-traceid JfrArtifactSet::markPackage(const char* const name, uintptr_t hash) {
-  return _symbol_id->markPackage(name, hash);
+traceid JfrArtifactSet::markPackage(const char* const name, uintptr_t hash, bool leakp) {
+  return _symbol_id->markPackage(name, hash, leakp);
 }
 
 traceid JfrArtifactSet::mark(const Symbol* symbol, bool leakp) {
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSetUtils.hpp b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSetUtils.hpp
index 44fe244d69fe82cec748849448a1479830bae062..328835852a20bf3bd20ccd6d44fde16fc4ab3290 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSetUtils.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSetUtils.hpp
@@ -256,7 +256,7 @@ class JfrSymbolId : public JfrCHeapObj {
   void clear();
   void set_class_unload(bool class_unload);
 
-  traceid markPackage(const char* name, uintptr_t hash);
+  traceid markPackage(const char* name, uintptr_t hash, bool leakp);
 
   template <typename T>
   void iterate_packages(T& functor) {
@@ -318,7 +318,7 @@ class JfrArtifactSet : public JfrCHeapObj {
   traceid mark_unsafe_anonymous_klass_name(const Klass* klass, bool leakp);
   traceid bootstrap_name(bool leakp);
 
-  traceid markPackage(const char* const name, uintptr_t hash);
+  traceid markPackage(const char* const name, uintptr_t hash, bool leakp);
 
   const JfrSymbolId::SymbolEntry* map_symbol(const Symbol* symbol) const;
   const JfrSymbolId::SymbolEntry* map_symbol(uintptr_t hash) const;
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.cpp b/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.cpp
index 666f434942b8340a02f22330f9a37cd4d894306f..407e65911999093769a466eb3e8c9ba30958484b 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.cpp
@@ -33,7 +33,6 @@
 #include "oops/method.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/atomic.inline.hpp"
-#include "runtime/orderAccess.inline.hpp"
 #include "runtime/vm_version.hpp"
 #include "runtime/jniHandles.hpp"
 #include "runtime/thread.inline.hpp"
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp b/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp
index c087048c8022c314df0847a7a50a987c10fcb5ce..5e5a6e67dc4d2463f523fe6d7aa6d0de792bf977 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp
@@ -29,7 +29,6 @@
 #include "jfr/recorder/checkpoint/types/traceid/jfrTraceId.hpp"
 #include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdBits.inline.hpp"
 #include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp"
-#include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdMacros.hpp"
 #include "jfr/support/jfrKlassExtension.hpp"
 #include "oops/arrayKlass.hpp"
 #include "oops/klass.hpp"
@@ -58,7 +57,14 @@ inline traceid JfrTraceId::get(const Thread* t) {
 
 inline traceid JfrTraceId::use(const Klass* klass) {
   assert(klass != NULL, "invariant");
-  return set_used_and_get(klass);
+  if (SHOULD_TAG(klass)) {
+    SET_USED_THIS_EPOCH(klass);
+    assert(USED_THIS_EPOCH(klass), "invariant");
+    JfrTraceIdEpoch::set_changed_tag_state();
+    return get(klass);
+  }
+  assert(USED_THIS_EPOCH(klass), "invariant");
+  return TRACE_ID(klass);
 }
 
 inline traceid JfrTraceId::use(const Method* method) {
@@ -69,10 +75,16 @@ inline traceid JfrTraceId::use(const Method* method) {
 inline traceid JfrTraceId::use(const Klass* klass, const Method* method) {
   assert(klass != NULL, "invariant");
   assert(method != NULL, "invariant");
-  SET_METHOD_FLAG_USED_THIS_EPOCH(method);
-
-  SET_METHOD_AND_CLASS_USED_THIS_EPOCH(klass);
+  if (SHOULD_TAG_KLASS_METHOD(klass)) {
+    SET_METHOD_AND_CLASS_USED_THIS_EPOCH(klass);
+  }
   assert(METHOD_AND_CLASS_USED_THIS_EPOCH(klass), "invariant");
+  if (METHOD_FLAG_NOT_USED_THIS_EPOCH(method)) {
+    assert(USED_THIS_EPOCH(klass), "invariant");
+    SET_METHOD_FLAG_USED_THIS_EPOCH(method);
+    JfrTraceIdEpoch::set_changed_tag_state();
+  }
+  assert(METHOD_FLAG_USED_THIS_EPOCH(method), "invariant");
   return (METHOD_ID(klass, method));
 }
 
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.cpp b/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.cpp
index 80c4b0ac1759a3a95a76c9d84f559bc6c880d297..aa38d30eb1556838916c1cf215b6df2b1c673f1a 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.cpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,15 +25,13 @@
 #include "precompiled.hpp"
 #include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp"
 #include "runtime/safepoint.hpp"
-#include "runtime/orderAccess.hpp"
 
 // Alternating epochs on each rotation allow for concurrent tagging.
-// The regular epoch shift happens only during a safepoint.
-// The fence is there only for the emergency dump case which happens outside of safepoint.
+// The epoch shift happens only during a safepoint.
 bool JfrTraceIdEpoch::_epoch_state = false;
+bool volatile JfrTraceIdEpoch::_tag_state = false;
+
 void JfrTraceIdEpoch::shift_epoch() {
+  assert(SafepointSynchronize::is_at_safepoint(), "invariant");
   _epoch_state = !_epoch_state;
-  if (!SafepointSynchronize::is_at_safepoint()) {
-    OrderAccess::fence();
-  }
 }
diff --git a/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp b/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp
index 1374521d2a423fffb9ac47db42becfd11ebafdac..9ab83d6d2d50f980d37565dc6fcfdaf69b45bde2 100644
--- a/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp
+++ b/src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp
@@ -25,18 +25,19 @@
 #ifndef SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDEPOCH_HPP
 #define SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDEPOCH_HPP
 
-#include "memory/allocation.hpp"
 #include "jfr/utilities/jfrTypes.hpp"
+#include "memory/allocation.hpp"
+#include "runtime/orderAccess.hpp"
 
-#define USED_BIT 1
-#define METHOD_USED_BIT (USED_BIT << 2)
-#define EPOCH_1_SHIFT 0
-#define EPOCH_2_SHIFT 1
-#define USED_EPOCH_1_BIT (USED_BIT << EPOCH_1_SHIFT)
-#define USED_EPOCH_2_BIT (USED_BIT << EPOCH_2_SHIFT)
-#define METHOD_USED_EPOCH_1_BIT (METHOD_USED_BIT << EPOCH_1_SHIFT)
-#define METHOD_USED_EPOCH_2_BIT (METHOD_USED_BIT << EPOCH_2_SHIFT)
-#define METHOD_AND_CLASS_IN_USE_BITS (METHOD_USED_BIT | USED_BIT)
+#define USED_BIT                             1
+#define METHOD_USED_BIT                      (USED_BIT << 2)
+#define EPOCH_1_SHIFT                        0
+#define EPOCH_2_SHIFT                        1
+#define USED_EPOCH_1_BIT                     (USED_BIT << EPOCH_1_SHIFT)
+#define USED_EPOCH_2_BIT                     (USED_BIT << EPOCH_2_SHIFT)
+#define METHOD_USED_EPOCH_1_BIT              (METHOD_USED_BIT << EPOCH_1_SHIFT)
+#define METHOD_USED_EPOCH_2_BIT              (METHOD_USED_BIT << EPOCH_2_SHIFT)
+#define METHOD_AND_CLASS_IN_USE_BITS         (METHOD_USED_BIT | USED_BIT)
 #define METHOD_AND_CLASS_IN_USE_EPOCH_1_BITS (METHOD_AND_CLASS_IN_USE_BITS << EPOCH_1_SHIFT)
 #define METHOD_AND_CLASS_IN_USE_EPOCH_2_BITS (METHOD_AND_CLASS_IN_USE_BITS << EPOCH_2_SHIFT)
 
@@ -44,6 +45,8 @@ class JfrTraceIdEpoch : AllStatic {
   friend class JfrCheckpointManager;
  private:
   static bool _epoch_state;
+  static bool volatile _tag_state;
+
   static void shift_epoch();
 
  public:
@@ -86,6 +89,20 @@ class JfrTraceIdEpoch : AllStatic {
   static traceid method_and_class_in_use_prev_epoch_bits() {
     return _epoch_state ? METHOD_AND_CLASS_IN_USE_EPOCH_1_BITS :  METHOD_AND_CLASS_IN_USE_EPOCH_2_BITS;
   }
+
+  static bool has_changed_tag_state() {
+    if ((bool)OrderAccess::load_acquire((volatile jubyte*)&_tag_state)) {
+      OrderAccess::release_store((volatile jubyte*)&_tag_state, (jubyte)false);
+      return true;
+    }
+    return false;
+  }
+
+  static void set_changed_tag_state() {
+    if (!(bool)OrderAccess::load_acquire((volatile jubyte*)&_tag_state)) {
+      OrderAccess::release_store((volatile jubyte*)&_tag_state, (jubyte)true);
+    }
+  }
 };
 
 #endif // SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEIDEPOCH_HPP
diff --git a/src/share/vm/jfr/recorder/repository/jfrChunk.cpp b/src/share/vm/jfr/recorder/repository/jfrChunk.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..fddeaf9047149381a3dc322dc23873f868b9daa9
--- /dev/null
+++ b/src/share/vm/jfr/recorder/repository/jfrChunk.cpp
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "jfr/recorder/repository/jfrChunk.hpp"
+#include "jfr/recorder/service/jfrOptionSet.hpp"
+#include "jfr/utilities/jfrTime.hpp"
+#include "jfr/utilities/jfrTimeConverter.hpp"
+#include "jfr/utilities/jfrTypes.hpp"
+#include "runtime/os.hpp"
+
+static const char* const MAGIC = "FLR";
+static const u2 JFR_VERSION_MAJOR = 2;
+static const u2 JFR_VERSION_MINOR = 1;
+
+// strictly monotone
+static jlong nanos_now() {
+  static jlong last = 0;
+  const jlong now = os::javaTimeMillis() * JfrTimeConverter::NANOS_PER_MILLISEC;
+  if (now > last) {
+    last = now;
+  } else {
+    ++last;
+  }
+  return last;
+}
+
+static jlong ticks_now() {
+  return JfrTicks::now();
+}
+
+JfrChunk::JfrChunk() :
+  _path(NULL),
+  _start_ticks(0),
+  _previous_start_ticks(invalid_time),
+  _start_nanos(0),
+  _previous_start_nanos(invalid_time),
+  _last_update_nanos(0),
+  _last_checkpoint_offset(0),
+  _last_metadata_offset(0),
+  _generation(1) {}
+
+JfrChunk::~JfrChunk() {
+  reset();
+}
+
+void JfrChunk::reset() {
+  if (_path != NULL) {
+    JfrCHeapObj::free(_path, strlen(_path) + 1);
+    _path = NULL;
+  }
+  _last_checkpoint_offset = _last_metadata_offset = 0;
+  _generation = 1;
+}
+
+const char* JfrChunk::magic() const {
+  return MAGIC;
+}
+
+u2 JfrChunk::major_version() const {
+  return JFR_VERSION_MAJOR;
+}
+
+u2 JfrChunk::minor_version() const {
+  return JFR_VERSION_MINOR;
+}
+
+u2 JfrChunk::capabilities() const {
+  // chunk capabilities, CompressedIntegers etc
+  static bool compressed_integers = JfrOptionSet::compressed_integers();
+  return compressed_integers;
+}
+
+int64_t JfrChunk::cpu_frequency() const {
+  static const jlong frequency = JfrTime::frequency();
+  return frequency;
+}
+
+void JfrChunk::set_last_checkpoint_offset(int64_t offset) {
+  _last_checkpoint_offset = offset;
+}
+
+int64_t JfrChunk::last_checkpoint_offset() const {
+  return _last_checkpoint_offset;
+}
+
+int64_t JfrChunk::start_ticks() const {
+  assert(_start_ticks != 0, "invariant");
+  return _start_ticks;
+}
+
+int64_t JfrChunk::start_nanos() const {
+  assert(_start_nanos != 0, "invariant");
+  return _start_nanos;
+}
+
+int64_t JfrChunk::previous_start_ticks() const {
+  assert(_previous_start_ticks != invalid_time, "invariant");
+  return _previous_start_ticks;
+}
+
+int64_t JfrChunk::previous_start_nanos() const {
+  assert(_previous_start_nanos != invalid_time, "invariant");
+  return _previous_start_nanos;
+}
+
+void JfrChunk::update_start_ticks() {
+  _start_ticks = ticks_now();
+}
+
+void JfrChunk::update_start_nanos() {
+  const jlong now = nanos_now();
+  assert(now > _start_nanos, "invariant");
+  assert(now > _last_update_nanos, "invariant");
+  _start_nanos = _last_update_nanos = now;
+}
+
+void JfrChunk::update_current_nanos() {
+  const jlong now = nanos_now();
+  assert(now > _last_update_nanos, "invariant");
+  _last_update_nanos = now;
+}
+
+void JfrChunk::save_current_and_update_start_ticks() {
+  _previous_start_ticks = _start_ticks;
+  update_start_ticks();
+}
+
+void JfrChunk::save_current_and_update_start_nanos() {
+  _previous_start_nanos = _start_nanos;
+  update_start_nanos();
+}
+
+void JfrChunk::set_time_stamp() {
+  save_current_and_update_start_nanos();
+  save_current_and_update_start_ticks();
+}
+
+int64_t JfrChunk::last_chunk_duration() const {
+  assert(_previous_start_nanos != invalid_time, "invariant");
+  return _start_nanos - _previous_start_nanos;
+}
+
+static char* copy_path(const char* path) {
+  assert(path != NULL, "invariant");
+  const size_t path_len = strlen(path);
+  char* new_path = JfrCHeapObj::new_array<char>(path_len + 1);
+  strncpy(new_path, path, path_len + 1);
+  return new_path;
+}
+
+void JfrChunk::set_path(const char* path) {
+  if (_path != NULL) {
+    JfrCHeapObj::free(_path, strlen(_path) + 1);
+    _path = NULL;
+  }
+  if (path != NULL) {
+    _path = copy_path(path);
+  }
+}
+
+const char* JfrChunk::path() const {
+  return _path;
+}
+
+bool JfrChunk::is_started() const {
+  return _start_nanos != 0;
+}
+
+bool JfrChunk::is_finished() const {
+  return 0 == _generation;
+}
+
+int64_t JfrChunk::duration() const {
+  assert(_last_update_nanos >= _start_nanos, "invariant");
+  return _last_update_nanos - _start_nanos;
+}
+
+int64_t JfrChunk::last_metadata_offset() const {
+  return _last_metadata_offset;
+}
+
+void JfrChunk::set_last_metadata_offset(int64_t offset) {
+  assert(offset > _last_metadata_offset, "invariant");
+  _last_metadata_offset = offset;
+}
+
+bool JfrChunk::has_metadata() const {
+  return 0 != _last_metadata_offset;
+}
+
+u1 JfrChunk::generation() const {
+  assert(_generation > 0, "invariant");
+  const u1 this_generation = _generation++;
+  if (GUARD == _generation) {
+    _generation = 1;
+  }
+  return this_generation;
+}
+
+u1 JfrChunk::next_generation() const {
+  assert(_generation > 0, "invariant");
+  const u1 next_gen = _generation;
+  return GUARD == next_gen ? 1 : next_gen;
+}
diff --git a/src/share/vm/jfr/recorder/repository/jfrChunkState.hpp b/src/share/vm/jfr/recorder/repository/jfrChunk.hpp
similarity index 53%
rename from src/share/vm/jfr/recorder/repository/jfrChunkState.hpp
rename to src/share/vm/jfr/recorder/repository/jfrChunk.hpp
index 0d3dfa1bd557cd125652a98be66034763817eeae..26073b9aa3bdb1e4f2eaa50039372e6d25f9e47d 100644
--- a/src/share/vm/jfr/recorder/repository/jfrChunkState.hpp
+++ b/src/share/vm/jfr/recorder/repository/jfrChunk.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -22,39 +22,70 @@
  *
  */
 
-#ifndef SHARE_VM_JFR_RECORDER_REPOSITORY_JFRRCHUNKSTATE_HPP
-#define SHARE_VM_JFR_RECORDER_REPOSITORY_JFRRCHUNKSTATE_HPP
+#ifndef SHARE_VM_JFR_RECORDER_REPOSITORY_JFRRCHUNK_HPP
+#define SHARE_VM_JFR_RECORDER_REPOSITORY_JFRRCHUNK_HPP
 
-#include "jni.h"
 #include "jfr/utilities/jfrAllocation.hpp"
-#include "jfr/utilities/jfrTypes.hpp"
 
-class JfrChunkState : public JfrCHeapObj {
+const u1 COMPLETE = 0;
+const u1 GUARD = 0xff;
+const u1 PAD = 0;
+
+class JfrChunk : public JfrCHeapObj {
   friend class JfrChunkWriter;
+  friend class JfrChunkHeadWriter;
  private:
   char* _path;
-  jlong _start_ticks;
-  jlong _start_nanos;
-  jlong _previous_start_ticks;
-  jlong _previous_start_nanos;
+  int64_t _start_ticks;
+  int64_t _previous_start_ticks;
+  int64_t _start_nanos;
+  int64_t _previous_start_nanos;
+  int64_t _last_update_nanos;
   int64_t _last_checkpoint_offset;
+  int64_t _last_metadata_offset;
+  mutable u1 _generation;
+
+  JfrChunk();
+  ~JfrChunk();
+  void reset();
+
+  const char* magic() const;
+  u2 major_version() const;
+  u2 minor_version() const;
+  int64_t cpu_frequency() const;
+  u2 capabilities() const;
 
   void update_start_ticks();
   void update_start_nanos();
   void save_current_and_update_start_ticks();
   void save_current_and_update_start_nanos();
 
-  JfrChunkState();
-  ~JfrChunkState();
-  void reset();
   int64_t last_checkpoint_offset() const;
   void set_last_checkpoint_offset(int64_t offset);
-  jlong previous_start_ticks() const;
-  jlong previous_start_nanos() const;
-  jlong last_chunk_duration() const;
-  void update_time_to_now();
+
+  int64_t last_metadata_offset() const;
+  void set_last_metadata_offset(int64_t offset);
+  bool has_metadata() const;
+
+  int64_t start_ticks() const;
+  int64_t start_nanos() const;
+
+  int64_t previous_start_ticks() const;
+  int64_t previous_start_nanos() const;
+  int64_t last_chunk_duration() const;
+
+  void set_time_stamp();
+  void update_current_nanos();
+
   void set_path(const char* path);
   const char* path() const;
+
+  bool is_started() const;
+  bool is_finished() const;
+
+  int64_t duration() const;
+  u1 generation() const;
+  u1 next_generation() const;
 };
 
-#endif // SHARE_VM_JFR_RECORDER_REPOSITORY_JFRRCHUNKSTATE_HPP
+#endif // SHARE_VM_JFR_RECORDER_REPOSITORY_JFRRCHUNK_HPP
diff --git a/src/share/vm/jfr/recorder/repository/jfrChunkState.cpp b/src/share/vm/jfr/recorder/repository/jfrChunkState.cpp
deleted file mode 100644
index f48716d33f0d7727d523d5e46849e30f074088d1..0000000000000000000000000000000000000000
--- a/src/share/vm/jfr/recorder/repository/jfrChunkState.cpp
+++ /dev/null
@@ -1,119 +0,0 @@
-/*
- * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- *
- */
-
-#include "precompiled.hpp"
-#include "jfr/dcmd/jfrDcmds.hpp"
-#include "jfr/recorder/jfrRecorder.hpp"
-#include "jfr/recorder/repository/jfrChunkState.hpp"
-#include "jfr/recorder/repository/jfrChunkWriter.hpp"
-#include "jfr/utilities/jfrTime.hpp"
-#include "jfr/utilities/jfrTimeConverter.hpp"
-#include "runtime/os.hpp"
-#include "runtime/thread.inline.hpp"
-
-JfrChunkState::JfrChunkState() :
-  _path(NULL),
-  _start_ticks(0),
-  _start_nanos(0),
-  _previous_start_ticks(0),
-  _previous_start_nanos(0),
-  _last_checkpoint_offset(0) {}
-
-JfrChunkState::~JfrChunkState() {
-  reset();
-}
-
-void JfrChunkState::reset() {
-  if (_path != NULL) {
-    JfrCHeapObj::free(_path, strlen(_path) + 1);
-    _path = NULL;
-  }
-  set_last_checkpoint_offset(0);
-}
-
-void JfrChunkState::set_last_checkpoint_offset(int64_t offset) {
-  _last_checkpoint_offset = offset;
-}
-
-int64_t JfrChunkState::last_checkpoint_offset() const {
-  return _last_checkpoint_offset;
-}
-
-jlong JfrChunkState::previous_start_ticks() const {
-  return _previous_start_ticks;
-}
-
-jlong JfrChunkState::previous_start_nanos() const {
-  return _previous_start_nanos;
-}
-
-void JfrChunkState::update_start_ticks() {
-  _start_ticks = JfrTicks::now();
-}
-
-void JfrChunkState::update_start_nanos() {
-  _start_nanos = (jlong)(os::javaTimeMillis() * JfrTimeConverter::NANOS_PER_MILLISEC);
-}
-
-void JfrChunkState::save_current_and_update_start_ticks() {
-  _previous_start_ticks = _start_ticks;
-  update_start_ticks();
-}
-
-void JfrChunkState::save_current_and_update_start_nanos() {
-  _previous_start_nanos = _start_nanos;
-  update_start_nanos();
-}
-
-void JfrChunkState::update_time_to_now() {
-  save_current_and_update_start_nanos();
-  save_current_and_update_start_ticks();
-}
-
-jlong JfrChunkState::last_chunk_duration() const {
-  return _start_nanos - _previous_start_nanos;
-}
-
-static char* copy_path(const char* path) {
-  assert(path != NULL, "invariant");
-  const size_t path_len = strlen(path);
-  char* new_path = JfrCHeapObj::new_array<char>(path_len + 1);
-  strncpy(new_path, path, path_len + 1);
-  return new_path;
-}
-
-void JfrChunkState::set_path(const char* path) {
-  assert(JfrStream_lock->owned_by_self(), "invariant");
-  if (_path != NULL) {
-    JfrCHeapObj::free(_path, strlen(_path) + 1);
-    _path = NULL;
-  }
-  if (path != NULL) {
-    _path = copy_path(path);
-  }
-}
-
-const char* JfrChunkState::path() const {
-  return _path;
-}
diff --git a/src/share/vm/jfr/recorder/repository/jfrChunkWriter.cpp b/src/share/vm/jfr/recorder/repository/jfrChunkWriter.cpp
index 928404d0e0d9d40993b529a4656f6acd0b000de9..9f10a7211e9e124d114a8177fef02cef5f06493d 100644
--- a/src/share/vm/jfr/recorder/repository/jfrChunkWriter.cpp
+++ b/src/share/vm/jfr/recorder/repository/jfrChunkWriter.cpp
@@ -23,83 +23,219 @@
  */
 
 #include "precompiled.hpp"
-#include "jfr/recorder/repository/jfrChunkState.hpp"
+#include "jfr/recorder/repository/jfrChunk.hpp"
 #include "jfr/recorder/repository/jfrChunkWriter.hpp"
-#include "jfr/recorder/service/jfrOptionSet.hpp"
 #include "jfr/utilities/jfrTime.hpp"
-#include "jfr/utilities/jfrTypes.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/os.hpp"
-#include "runtime/os.hpp"
-
-const u2 JFR_VERSION_MAJOR = 2;
-const u2 JFR_VERSION_MINOR = 0;
-
-static const size_t MAGIC_LEN = 4;
-static const size_t FILEHEADER_SLOT_SIZE = 8;
-static const size_t CHUNK_SIZE_OFFSET = 8;
-
-JfrChunkWriter::JfrChunkWriter() : JfrChunkWriterBase(NULL), _chunkstate(NULL) {}
 
-bool JfrChunkWriter::initialize() {
-  assert(_chunkstate == NULL, "invariant");
-  _chunkstate = new JfrChunkState();
-  return _chunkstate != NULL;
-}
+static const int64_t MAGIC_OFFSET = 0;
+static const int64_t MAGIC_LEN = 4;
+static const int64_t VERSION_OFFSET = MAGIC_LEN;
+static const int64_t SIZE_OFFSET = 8;
+static const int64_t SLOT_SIZE = 8;
+static const int64_t CHECKPOINT_OFFSET = SIZE_OFFSET + SLOT_SIZE;
+static const int64_t METADATA_OFFSET = CHECKPOINT_OFFSET + SLOT_SIZE;
+static const int64_t START_NANOS_OFFSET = METADATA_OFFSET + SLOT_SIZE;
+static const int64_t DURATION_NANOS_OFFSET = START_NANOS_OFFSET + SLOT_SIZE;
+static const int64_t START_TICKS_OFFSET = DURATION_NANOS_OFFSET + SLOT_SIZE;
+static const int64_t CPU_FREQUENCY_OFFSET = START_TICKS_OFFSET + SLOT_SIZE;
+static const int64_t GENERATION_OFFSET = CPU_FREQUENCY_OFFSET + SLOT_SIZE;
+static const int64_t CAPABILITY_OFFSET = GENERATION_OFFSET + 2;
+static const int64_t HEADER_SIZE = CAPABILITY_OFFSET + 2;
 
 static fio_fd open_chunk(const char* path) {
   assert(JfrStream_lock->owned_by_self(), "invariant");
   return path != NULL ? os::open(path, O_CREAT | O_RDWR, S_IREAD | S_IWRITE) : invalid_fd;
 }
 
-bool JfrChunkWriter::open() {
-  assert(_chunkstate != NULL, "invariant");
-  JfrChunkWriterBase::reset(open_chunk(_chunkstate->path()));
-  const bool is_open = this->has_valid_fd();
-  if (is_open) {
-    this->bytes("FLR", MAGIC_LEN);
-    this->be_write((u2)JFR_VERSION_MAJOR);
-    this->be_write((u2)JFR_VERSION_MINOR);
-    this->reserve(6 * FILEHEADER_SLOT_SIZE);
-    // u8 chunk_size
-    // u8 initial checkpoint offset
-    // u8 metadata section offset
-    // u8 chunk start nanos
-    // u8 chunk duration nanos
-    // u8 chunk start ticks
-    this->be_write(JfrTime::frequency());
-    // chunk capabilities, CompressedIntegers etc
-    this->be_write((u4)JfrOptionSet::compressed_integers() ? 1 : 0);
-    _chunkstate->reset();
+#ifdef ASSERT
+static void assert_writer_position(JfrChunkWriter* writer, int64_t offset) {
+  assert(writer != NULL, "invariant");
+  assert(offset == writer->current_offset(), "invariant");
+}
+#endif
+
+class JfrChunkHeadWriter : public StackObj {
+ private:
+  JfrChunkWriter* _writer;
+  JfrChunk* _chunk;
+ public:
+  void write_magic() {
+    _writer->bytes(_chunk->magic(), MAGIC_LEN);
   }
-  return is_open;
+
+  void write_version() {
+    _writer->be_write(_chunk->major_version());
+    _writer->be_write(_chunk->minor_version());
+  }
+
+  void write_size(int64_t size) {
+    _writer->be_write(size);
+  }
+
+  void write_checkpoint() {
+    _writer->be_write(_chunk->last_checkpoint_offset());
+  }
+
+  void write_metadata() {
+    _writer->be_write(_chunk->last_metadata_offset());
+  }
+
+  void write_time(bool finalize) {
+    if (finalize) {
+      _writer->be_write(_chunk->previous_start_nanos());
+      _writer->be_write(_chunk->last_chunk_duration());
+      _writer->be_write(_chunk->previous_start_ticks());
+      return;
+    }
+    _writer->be_write(_chunk->start_nanos());
+    _writer->be_write(_chunk->duration());
+    _writer->be_write(_chunk->start_ticks());
+  }
+
+  void write_cpu_frequency() {
+    _writer->be_write(_chunk->cpu_frequency());
+  }
+
+  void write_generation(bool finalize) {
+    _writer->be_write(finalize ? COMPLETE : _chunk->generation());
+    _writer->be_write(PAD);
+  }
+
+  void write_next_generation() {
+    _writer->be_write(_chunk->next_generation());
+    _writer->be_write(PAD);
+  }
+
+  void write_guard() {
+    _writer->be_write(GUARD);
+    _writer->be_write(PAD);
+  }
+
+  void write_guard_flush() {
+    write_guard();
+    _writer->flush();
+  }
+
+  void write_capabilities() {
+    _writer->be_write(_chunk->capabilities());
+  }
+
+  void write_size_to_generation(int64_t size, bool finalize) {
+    write_size(size);
+    write_checkpoint();
+    write_metadata();
+    write_time(finalize);
+    write_cpu_frequency();
+    write_generation(finalize);
+  }
+
+  void flush(int64_t size, bool finalize) {
+    assert(_writer->is_valid(), "invariant");
+    assert(_chunk != NULL, "invariant");
+    DEBUG_ONLY(assert_writer_position(_writer, SIZE_OFFSET);)
+    write_size_to_generation(size, finalize);
+    // no need to write capabilities
+    _writer->seek(size); // implicit flush
+  }
+
+  void initialize() {
+    assert(_writer->is_valid(), "invariant");
+    assert(_chunk != NULL, "invariant");
+    DEBUG_ONLY(assert_writer_position(_writer, 0);)
+    write_magic();
+    write_version();
+    write_size_to_generation(HEADER_SIZE, false);
+    write_capabilities();
+    DEBUG_ONLY(assert_writer_position(_writer, HEADER_SIZE);)
+    _writer->flush();
+  }
+
+  JfrChunkHeadWriter(JfrChunkWriter* writer, int64_t offset, bool guard = true) : _writer(writer), _chunk(writer->_chunk) {
+    assert(_writer != NULL, "invariant");
+    assert(_writer->is_valid(), "invariant");
+    assert(_chunk != NULL, "invariant");
+    if (0 == _writer->current_offset()) {
+      assert(HEADER_SIZE == offset, "invariant");
+      initialize();
+    } else {
+      if (guard) {
+        _writer->seek(GENERATION_OFFSET);
+        write_guard();
+        _writer->seek(offset);
+      } else {
+        _chunk->update_current_nanos();
+      }
+    }
+    DEBUG_ONLY(assert_writer_position(_writer, offset);)
+  }
+};
+
+static int64_t prepare_chunk_header_constant_pool(JfrChunkWriter& cw, int64_t event_offset, bool flushpoint) {
+  const int64_t delta = cw.last_checkpoint_offset() == 0 ? 0 : cw.last_checkpoint_offset() - event_offset;
+  const u4 checkpoint_type = flushpoint ? (u4)(FLUSH | HEADER) : (u4)HEADER;
+  cw.reserve(sizeof(u4));
+  cw.write<u8>(EVENT_CHECKPOINT);
+  cw.write<u8>(JfrTicks::now().value());
+  cw.write<u8>(0); // duration
+  cw.write<u8>(delta); // to previous checkpoint
+  cw.write<u4>(checkpoint_type);
+  cw.write<u4>(1); // pool count
+  cw.write<u8>(TYPE_CHUNKHEADER);
+  cw.write<u4>(1); // count
+  cw.write<u8>(1); // key
+  cw.write<u4>(HEADER_SIZE); // length of byte array
+  return cw.current_offset();
 }
 
-size_t JfrChunkWriter::close(intptr_t metadata_offset) {
-  write_header(metadata_offset);
-  this->flush();
-  this->close_fd();
-  return size_written();
+int64_t JfrChunkWriter::write_chunk_header_checkpoint(bool flushpoint) {
+  assert(this->has_valid_fd(), "invariant");
+  const int64_t event_size_offset = current_offset();
+  const int64_t header_content_pos = prepare_chunk_header_constant_pool(*this, event_size_offset, flushpoint);
+  JfrChunkHeadWriter head(this, header_content_pos, false);
+  head.write_magic();
+  head.write_version();
+  const int64_t chunk_size_offset = reserve(sizeof(int64_t)); // size to be decided when we are done
+  be_write(event_size_offset); // last checkpoint offset will be this checkpoint
+  head.write_metadata();
+  head.write_time(false);
+  head.write_cpu_frequency();
+  head.write_next_generation();
+  head.write_capabilities();
+  assert(current_offset() - header_content_pos == HEADER_SIZE, "invariant");
+  const u4 checkpoint_size = current_offset() - event_size_offset;
+  write_padded_at_offset<u4>(checkpoint_size, event_size_offset);
+  set_last_checkpoint_offset(event_size_offset);
+  const size_t sz_written = size_written();
+  write_be_at_offset(sz_written, chunk_size_offset);
+  return sz_written;
 }
 
-void JfrChunkWriter::write_header(intptr_t metadata_offset) {
-  assert(this->is_valid(), "invariant");
-  // Chunk size
-  this->write_be_at_offset((jlong)size_written(), CHUNK_SIZE_OFFSET);
-  // initial checkpoint event offset
-  this->write_be_at_offset(_chunkstate->last_checkpoint_offset(), CHUNK_SIZE_OFFSET + (1 * FILEHEADER_SLOT_SIZE));
-  // metadata event offset
-  this->write_be_at_offset((jlong)metadata_offset, CHUNK_SIZE_OFFSET + (2 * FILEHEADER_SLOT_SIZE));
-  // start of chunk in nanos since epoch
-  this->write_be_at_offset(_chunkstate->previous_start_nanos(), CHUNK_SIZE_OFFSET + (3 * FILEHEADER_SLOT_SIZE));
-  // duration of chunk in nanos
-  this->write_be_at_offset(_chunkstate->last_chunk_duration(), CHUNK_SIZE_OFFSET + (4 * FILEHEADER_SLOT_SIZE));
-  // start of chunk in ticks
-  this->write_be_at_offset(_chunkstate->previous_start_ticks(), CHUNK_SIZE_OFFSET + (5 * FILEHEADER_SLOT_SIZE));
+int64_t JfrChunkWriter::flush_chunk(bool flushpoint) {
+  assert(_chunk != NULL, "invariant");
+  const int64_t sz_written = write_chunk_header_checkpoint(flushpoint);
+  assert(size_written() == sz_written, "invariant");
+  JfrChunkHeadWriter head(this, SIZE_OFFSET);
+  head.flush(sz_written, !flushpoint);
+  return sz_written;
 }
 
-void JfrChunkWriter::set_chunk_path(const char* chunk_path) {
-  _chunkstate->set_path(chunk_path);
+JfrChunkWriter::JfrChunkWriter() : JfrChunkWriterBase(NULL), _chunk(new JfrChunk()) {}
+
+JfrChunkWriter::~JfrChunkWriter() {
+  assert(_chunk != NULL, "invariant");
+  delete _chunk;
+}
+
+void JfrChunkWriter::set_path(const char* path) {
+  assert(_chunk != NULL, "invariant");
+  _chunk->set_path(path);
+}
+
+void JfrChunkWriter::set_time_stamp() {
+  assert(_chunk != NULL, "invariant");
+  _chunk->set_time_stamp();
 }
 
 intptr_t JfrChunkWriter::size_written() const {
@@ -107,13 +243,46 @@ intptr_t JfrChunkWriter::size_written() const {
 }
 
 int64_t JfrChunkWriter::last_checkpoint_offset() const {
-  return _chunkstate->last_checkpoint_offset();
+  assert(_chunk != NULL, "invariant");
+  return _chunk->last_checkpoint_offset();
+}
+
+int64_t JfrChunkWriter::current_chunk_start_nanos() const {
+  assert(_chunk != NULL, "invariant");
+  return this->is_valid() ? _chunk->start_nanos() : invalid_time;
 }
 
 void JfrChunkWriter::set_last_checkpoint_offset(int64_t offset) {
-  _chunkstate->set_last_checkpoint_offset(offset);
+  assert(_chunk != NULL, "invariant");
+  _chunk->set_last_checkpoint_offset(offset);
+}
+
+void JfrChunkWriter::set_last_metadata_offset(int64_t offset) {
+  assert(_chunk != NULL, "invariant");
+  _chunk->set_last_metadata_offset(offset);
+}
+
+bool JfrChunkWriter::has_metadata() const {
+  assert(_chunk != NULL, "invariant");
+  return _chunk->has_metadata();
 }
 
-void JfrChunkWriter::time_stamp_chunk_now() {
-  _chunkstate->update_time_to_now();
+bool JfrChunkWriter::open() {
+  assert(_chunk != NULL, "invariant");
+  JfrChunkWriterBase::reset(open_chunk(_chunk->path()));
+  const bool is_open = this->has_valid_fd();
+  if (is_open) {
+    assert(0 == this->current_offset(), "invariant");
+    _chunk->reset();
+    JfrChunkHeadWriter head(this, HEADER_SIZE);
+  }
+  return is_open;
+}
+
+int64_t JfrChunkWriter::close() {
+  assert(this->has_valid_fd(), "invariant");
+  const int64_t size_written = flush_chunk(false);
+  this->close_fd();
+  assert(!this->is_valid(), "invariant");
+  return size_written;
 }
diff --git a/src/share/vm/jfr/recorder/repository/jfrChunkWriter.hpp b/src/share/vm/jfr/recorder/repository/jfrChunkWriter.hpp
index c26a17143d5759accf86274d8681c2026fb645ed..707f995b7afcebde33f1ddef7ff1a56690b250a9 100644
--- a/src/share/vm/jfr/recorder/repository/jfrChunkWriter.hpp
+++ b/src/share/vm/jfr/recorder/repository/jfrChunkWriter.hpp
@@ -29,29 +29,36 @@
 #include "jfr/writers/jfrStreamWriterHost.inline.hpp"
 #include "jfr/writers/jfrWriterHost.inline.hpp"
 
-typedef MallocAdapter<M> JfrStreamBuffer; // 1 mb buffered writes
-typedef StreamWriterHost<JfrStreamBuffer, JfrCHeapObj> JfrBufferedStreamWriter;
-typedef WriterHost<BigEndianEncoder, CompressedIntegerEncoder, JfrBufferedStreamWriter> JfrChunkWriterBase;
+typedef MallocAdapter<M> JfrChunkBuffer; // 1 mb buffered writes
+typedef StreamWriterHost<JfrChunkBuffer, JfrCHeapObj> JfrBufferedChunkWriter;
+typedef WriterHost<BigEndianEncoder, CompressedIntegerEncoder, JfrBufferedChunkWriter> JfrChunkWriterBase;
 
-class JfrChunkState;
+class JfrChunk;
+class JfrChunkHeadWriter;
 
 class JfrChunkWriter : public JfrChunkWriterBase {
+  friend class JfrChunkHeadWriter;
   friend class JfrRepository;
  private:
-  JfrChunkState* _chunkstate;
-
+  JfrChunk* _chunk;
+  void set_path(const char* path);
+  int64_t flush_chunk(bool flushpoint);
   bool open();
-  size_t close(intptr_t metadata_offset);
-  void write_header(intptr_t metadata_offset);
-  void set_chunk_path(const char* chunk_path);
+  int64_t close();
+  int64_t current_chunk_start_nanos() const;
+  int64_t write_chunk_header_checkpoint(bool flushpoint);
 
  public:
   JfrChunkWriter();
-  bool initialize();
+  ~JfrChunkWriter();
+
   intptr_t size_written() const;
   int64_t last_checkpoint_offset() const;
   void set_last_checkpoint_offset(int64_t offset);
-  void time_stamp_chunk_now();
+  void set_last_metadata_offset(int64_t offset);
+
+  bool has_metadata() const;
+  void set_time_stamp();
 };
 
 #endif // SHARE_VM_JFR_RECORDER_REPOSITORY_JFRCHUNKWRITER_HPP
diff --git a/src/share/vm/jfr/recorder/repository/jfrEmergencyDump.cpp b/src/share/vm/jfr/recorder/repository/jfrEmergencyDump.cpp
index dd5ba88e123ae625e51932ee1b1a39ef1087e7d7..d76c66f268d7a1d7a3dd64b4b01575fcd4178f1a 100644
--- a/src/share/vm/jfr/recorder/repository/jfrEmergencyDump.cpp
+++ b/src/share/vm/jfr/recorder/repository/jfrEmergencyDump.cpp
@@ -246,7 +246,6 @@ static void write_emergency_file(fio_fd emergency_fd, const RepositoryIterator&
 }
 
 static const char* create_emergency_dump_path() {
-  assert(JfrStream_lock->owned_by_self(), "invariant");
   char* buffer = NEW_RESOURCE_ARRAY_RETURN_NULL(char, JVM_MAXPATHLEN);
   if (NULL == buffer) {
     return NULL;
@@ -288,7 +287,6 @@ static const char* create_emergency_dump_path() {
 // Caller needs ResourceMark
 static const char* create_emergency_chunk_path(const char* repository_path) {
   assert(repository_path != NULL, "invariant");
-  assert(JfrStream_lock->owned_by_self(), "invariant");
   const size_t repository_path_len = strlen(repository_path);
   // date time
   char date_time_buffer[32] = { 0 };
@@ -304,12 +302,11 @@ static const char* create_emergency_chunk_path(const char* repository_path) {
     return NULL;
   }
   // append the individual substrings
-  jio_snprintf(chunk_path, chunkname_max_len, "%s%s%s%s", repository_path_len, os::file_separator(), date_time_buffer, chunk_file_jfr_ext);
+  jio_snprintf(chunk_path, chunkname_max_len, "%s%s%s%s", repository_path, os::file_separator(), date_time_buffer, chunk_file_jfr_ext);
   return chunk_path;
 }
 
 static fio_fd emergency_dump_file_descriptor() {
-  assert(JfrStream_lock->owned_by_self(), "invariant");
   ResourceMark rm;
   const char* const emergency_dump_path = create_emergency_dump_path();
   return emergency_dump_path != NULL ? open_exclusivly(emergency_dump_path) : invalid_fd;
@@ -322,7 +319,6 @@ const char* JfrEmergencyDump::build_dump_path(const char* repository_path) {
 void JfrEmergencyDump::on_vm_error(const char* repository_path) {
   assert(repository_path != NULL, "invariant");
   ResourceMark rm;
-  MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
   const fio_fd emergency_fd = emergency_dump_file_descriptor();
   if (emergency_fd != invalid_fd) {
     RepositoryIterator iterator(repository_path, strlen(repository_path));
@@ -337,17 +333,25 @@ void JfrEmergencyDump::on_vm_error(const char* repository_path) {
 *
 * 1. if the thread state is not "_thread_in_vm", we will quick transition
 *    it to "_thread_in_vm".
-* 2. the nesting state for both resource and handle areas are unknown,
-*    so we allocate new fresh arenas, discarding the old ones.
-* 3. if the thread is the owner of some critical lock(s), unlock them.
+* 2. if the thread is the owner of some critical lock(s), unlock them.
 *
 * If we end up deadlocking in the attempt of dumping out jfr data,
 * we rely on the WatcherThread task "is_error_reported()",
-* to exit the VM after a hard-coded timeout.
+* to exit the VM after a hard-coded timeout (disallow WatcherThread to emergency dump).
 * This "safety net" somewhat explains the aggressiveness in this attempt.
 *
 */
-static void prepare_for_emergency_dump(Thread* thread) {
+static bool prepare_for_emergency_dump() {
+  if (JfrStream_lock->owned_by_self()) {
+    // crashed during jfr rotation, disallow recursion
+    return false;
+  }
+  Thread* const thread = Thread::current();
+  if (thread->is_Watcher_thread()) {
+    // need WatcherThread as a safeguard against potential deadlocks
+    return false;
+  }
+
   if (thread->is_Java_thread()) {
     ((JavaThread*)thread)->set_thread_state(_thread_in_vm);
   }
@@ -386,7 +390,6 @@ static void prepare_for_emergency_dump(Thread* thread) {
     VMOperationRequest_lock->unlock();
   }
 
-
   if (Service_lock->owned_by_self()) {
     Service_lock->unlock();
   }
@@ -407,13 +410,10 @@ static void prepare_for_emergency_dump(Thread* thread) {
     JfrBuffer_lock->unlock();
   }
 
-  if (JfrStream_lock->owned_by_self()) {
-    JfrStream_lock->unlock();
-  }
-
   if (JfrStacktrace_lock->owned_by_self()) {
     JfrStacktrace_lock->unlock();
   }
+  return true;
 }
 
 static volatile int jfr_shutdown_lock = 0;
@@ -423,24 +423,9 @@ static bool guard_reentrancy() {
 }
 
 void JfrEmergencyDump::on_vm_shutdown(bool exception_handler) {
-  if (!guard_reentrancy()) {
+  if (!(guard_reentrancy() && prepare_for_emergency_dump())) {
     return;
   }
-  // function made non-reentrant
-  Thread* thread = Thread::current();
-  if (exception_handler) {
-    // we are crashing
-    if (thread->is_Watcher_thread()) {
-      // The Watcher thread runs the periodic thread sampling task.
-      // If it has crashed, it is likely that another thread is
-      // left in a suspended state. This would mean the system
-      // will not be able to ever move to a safepoint. We try
-      // to avoid issuing safepoint operations when attempting
-      // an emergency dump, but a safepoint might be already pending.
-      return;
-    }
-    prepare_for_emergency_dump(thread);
-  }
   EventDumpReason event;
   if (event.should_commit()) {
     event.set_reason(exception_handler ? "Crash" : "Out of Memory");
@@ -452,8 +437,6 @@ void JfrEmergencyDump::on_vm_shutdown(bool exception_handler) {
     LeakProfiler::emit_events(max_jlong, false);
   }
   const int messages = MSGBIT(MSG_VM_ERROR);
-  ResourceMark rm(thread);
-  HandleMark hm(thread);
   JfrRecorderService service;
   service.rotate(messages);
 }
diff --git a/src/share/vm/jfr/recorder/repository/jfrRepository.cpp b/src/share/vm/jfr/recorder/repository/jfrRepository.cpp
index cf0022f4573cef536213c719eddcdde49f892c73..ebb1486b426991cfec90764e2be8893da5f968dc 100644
--- a/src/share/vm/jfr/recorder/repository/jfrRepository.cpp
+++ b/src/share/vm/jfr/recorder/repository/jfrRepository.cpp
@@ -26,7 +26,6 @@
 #include "jfr/jfr.hpp"
 #include "jfr/jni/jfrJavaSupport.hpp"
 #include "jfr/recorder/jfrRecorder.hpp"
-#include "jfr/recorder/repository/jfrChunkState.hpp"
 #include "jfr/recorder/repository/jfrChunkWriter.hpp"
 #include "jfr/recorder/repository/jfrEmergencyDump.hpp"
 #include "jfr/recorder/repository/jfrRepository.hpp"
@@ -44,11 +43,6 @@ JfrRepository& JfrRepository::instance() {
 
 static JfrChunkWriter* _chunkwriter = NULL;
 
-static bool initialize_chunkwriter() {
-  assert(_chunkwriter == NULL, "invariant");
-  _chunkwriter = new JfrChunkWriter();
-  return _chunkwriter != NULL && _chunkwriter->initialize();
-}
 
 JfrChunkWriter& JfrRepository::chunkwriter() {
   return *_chunkwriter;
@@ -57,7 +51,9 @@ JfrChunkWriter& JfrRepository::chunkwriter() {
 JfrRepository::JfrRepository(JfrPostBox& post_box) : _path(NULL), _post_box(post_box) {}
 
 bool JfrRepository::initialize() {
-  return initialize_chunkwriter();
+  assert(_chunkwriter == NULL, "invariant");
+  _chunkwriter = new JfrChunkWriter();
+  return _chunkwriter != NULL;
 }
 
 JfrRepository::~JfrRepository() {
@@ -85,7 +81,6 @@ void JfrRepository::destroy() {
 }
 
 void JfrRepository::on_vm_error() {
-  assert(!JfrStream_lock->owned_by_self(), "invariant");
   if (_path == NULL) {
     // completed already
     return;
@@ -108,17 +103,21 @@ bool JfrRepository::set_path(const char* path) {
   return true;
 }
 
-void JfrRepository::set_chunk_path(const char* path) {
-  assert(JfrStream_lock->owned_by_self(), "invariant");
-  chunkwriter().set_chunk_path(path);
-}
-
 void JfrRepository::notify_on_new_chunk_path() {
   if (Jfr::is_recording()) {
+    // rotations are synchronous, block until rotation completes
     instance()._post_box.post(MSG_ROTATE);
   }
 }
 
+void JfrRepository::set_chunk_path(const char* path) {
+  chunkwriter().set_path(path);
+}
+
+jlong JfrRepository::current_chunk_start_nanos() {
+  return chunkwriter().current_chunk_start_nanos();
+}
+
 /**
 * Sets the file where data should be written.
 *
@@ -135,14 +134,11 @@ void JfrRepository::set_chunk_path(jstring path, JavaThread* jt) {
   DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));
   ResourceMark rm(jt);
   const char* const canonical_chunk_path = JfrJavaSupport::c_str(path, jt);
-  {
-    MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
-    if (NULL == canonical_chunk_path && !_chunkwriter->is_valid()) {
-      // new output is NULL and current output is NULL
-      return;
-    }
-    instance().set_chunk_path(canonical_chunk_path);
+  if (NULL == canonical_chunk_path && !_chunkwriter->is_valid()) {
+    // new output is NULL and current output is NULL
+    return;
   }
+  instance().set_chunk_path(canonical_chunk_path);
   notify_on_new_chunk_path();
 }
 
@@ -156,14 +152,28 @@ void JfrRepository::set_path(jstring location, JavaThread* jt) {
 }
 
 bool JfrRepository::open_chunk(bool vm_error /* false */) {
-  assert(JfrStream_lock->owned_by_self(), "invariant");
   if (vm_error) {
     ResourceMark rm;
-    _chunkwriter->set_chunk_path(JfrEmergencyDump::build_dump_path(_path));
+    _chunkwriter->set_path(JfrEmergencyDump::build_dump_path(_path));
   }
   return _chunkwriter->open();
 }
 
-size_t JfrRepository::close_chunk(jlong metadata_offset) {
-  return _chunkwriter->close(metadata_offset);
+size_t JfrRepository::close_chunk() {
+  return _chunkwriter->close();
+}
+
+void JfrRepository::flush(JavaThread* jt) {
+  DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));
+  if (!Jfr::is_recording()) {
+    return;
+  }
+  if (!_chunkwriter->is_valid()) {
+    return;
+  }
+  instance()._post_box.post(MSG_FLUSHPOINT);
+}
+
+size_t JfrRepository::flush_chunk() {
+  return _chunkwriter->flush_chunk(true);
 }
diff --git a/src/share/vm/jfr/recorder/repository/jfrRepository.hpp b/src/share/vm/jfr/recorder/repository/jfrRepository.hpp
index 6b98df4f246631bbdf6b6a524b18a1ceadcc7af5..8c1b0edb23062d0dc457b9648c1a8b10abb411f9 100644
--- a/src/share/vm/jfr/recorder/repository/jfrRepository.hpp
+++ b/src/share/vm/jfr/recorder/repository/jfrRepository.hpp
@@ -55,8 +55,10 @@ class JfrRepository : public JfrCHeapObj {
   bool set_path(const char* path);
   void set_chunk_path(const char* path);
   bool open_chunk(bool vm_error = false);
-  size_t close_chunk(jlong metadata_offset);
+  size_t close_chunk();
+  size_t flush_chunk();
   void on_vm_error();
+
   static void notify_on_new_chunk_path();
   static JfrChunkWriter& chunkwriter();
 
@@ -68,6 +70,8 @@ class JfrRepository : public JfrCHeapObj {
  public:
   static void set_path(jstring location, JavaThread* jt);
   static void set_chunk_path(jstring path, JavaThread* jt);
+  static void flush(JavaThread* jt);
+  static jlong current_chunk_start_nanos();
 };
 
 #endif // SHARE_VM_JFR_RECORDER_REPOSITORY_JFRREPOSITORY_HPP
diff --git a/src/share/vm/jfr/recorder/service/jfrPostBox.cpp b/src/share/vm/jfr/recorder/service/jfrPostBox.cpp
index 88ec660588d19ef9ff8ad67142fbbe1e4050d621..cab3db4721550fb71210187ce99037f67f63823b 100644
--- a/src/share/vm/jfr/recorder/service/jfrPostBox.cpp
+++ b/src/share/vm/jfr/recorder/service/jfrPostBox.cpp
@@ -33,7 +33,8 @@
                              (MSGBIT(MSG_STOP))   |          \
                              (MSGBIT(MSG_START))  |          \
                              (MSGBIT(MSG_CLONE_IN_MEMORY)) | \
-                             (MSGBIT(MSG_VM_ERROR))          \
+                             (MSGBIT(MSG_VM_ERROR))        | \
+                             (MSGBIT(MSG_FLUSHPOINT))        \
                            )
 
 static JfrPostBox* _instance = NULL;
diff --git a/src/share/vm/jfr/recorder/service/jfrPostBox.hpp b/src/share/vm/jfr/recorder/service/jfrPostBox.hpp
index e17cd220465cf481f59b1b54c87743f1d92b04ba..6f30dbfca6a081bff02a90ef854726e7716ced30 100644
--- a/src/share/vm/jfr/recorder/service/jfrPostBox.hpp
+++ b/src/share/vm/jfr/recorder/service/jfrPostBox.hpp
@@ -41,6 +41,7 @@ enum JFR_Msg {
   MSG_SHUTDOWN,
   MSG_VM_ERROR,
   MSG_DEADBUFFER,
+  MSG_FLUSHPOINT,
   MSG_NO_OF_MSGS
 };
 
@@ -53,15 +54,16 @@ enum JFR_Msg {
  *  MSG_START(1)            ; MSGBIT(MSG_START) == (1 << 0x1) == 0x2
  *  MSG_STOP (2)            ; MSGBIT(MSG_STOP) == (1 << 0x2) == 0x4
  *  MSG_ROTATE (3)          ; MSGBIT(MSG_ROTATE) == (1 << 0x3) == 0x8
- *  MSG_VM_ERROR (8)        ; MSGBIT(MSG_VM_ERROR) == (1 << 8) == 0x100
+ *  MSG_VM_ERROR (8)        ; MSGBIT(MSG_VM_ERROR) == (1 << 0x8) == 0x100
+ *  MSG_FLUSHPOINT (10)     ; MSGBIT(MSG_FLUSHPOINT) == (1 << 0xa) == 0x400
  *
  *  Asynchronous messages (posting thread returns immediately upon deposit):
  *
  *  MSG_FULLBUFFER (4)      ; MSGBIT(MSG_FULLBUFFER) == (1 << 0x4) == 0x10
- *  MSG_CHECKPOINT (5)      ; MSGBIT(CHECKPOINT) == (1 << 5) == 0x20
- *  MSG_WAKEUP (6)          ; MSGBIT(WAKEUP) == (1 << 6) == 0x40
- *  MSG_SHUTDOWN (7)        ; MSGBIT(MSG_SHUTDOWN) == (1 << 7) == 0x80
- *  MSG_DEADBUFFER (9)      ; MSGBIT(MSG_DEADBUFFER) == (1 << 9) == 0x200
+ *  MSG_CHECKPOINT (5)      ; MSGBIT(CHECKPOINT) == (1 << 0x5) == 0x20
+ *  MSG_WAKEUP (6)          ; MSGBIT(WAKEUP) == (1 << 0x6) == 0x40
+ *  MSG_SHUTDOWN (7)        ; MSGBIT(MSG_SHUTDOWN) == (1 << 0x7) == 0x80
+ *  MSG_DEADBUFFER (9)      ; MSGBIT(MSG_DEADBUFFER) == (1 << 0x9) == 0x200
  */
 
 class JfrPostBox : public JfrCHeapObj {
diff --git a/src/share/vm/jfr/recorder/service/jfrRecorderService.cpp b/src/share/vm/jfr/recorder/service/jfrRecorderService.cpp
index ce5ae9677682a6b1c0c023941079f2486e967539..63189a5267c43ccceda5b5beda82b1d1f900d92c 100644
--- a/src/share/vm/jfr/recorder/service/jfrRecorderService.cpp
+++ b/src/share/vm/jfr/recorder/service/jfrRecorderService.cpp
@@ -23,6 +23,7 @@
  */
 
 #include "precompiled.hpp"
+#include "jfrfiles/jfrEventClasses.hpp"
 #include "jfr/jni/jfrJavaSupport.hpp"
 #include "jfr/leakprofiler/leakProfiler.hpp"
 #include "jfr/leakprofiler/checkpoint/objectSampleCheckpoint.hpp"
@@ -54,148 +55,281 @@
 #include "runtime/vm_operations.hpp"
 #include "runtime/vmThread.hpp"
 
-// set data iff *dest == NULL
-static bool try_set(void* const data, void** dest, bool clear) {
-  assert(data != NULL, "invariant");
-  void* const current = OrderAccess::load_ptr_acquire(dest);
-  if (current != NULL) {
-    if (current != data) {
-      // already set
-      return false;
-    }
-    assert(current == data, "invariant");
-    if (!clear) {
-      // recursion disallowed
-      return false;
-    }
-  }
-  return Atomic::cmpxchg_ptr(clear ? NULL : data, dest, current) == current;
-}
-
-static void* rotation_thread = NULL;
-static const int rotation_try_limit = 1000;
-static const int rotation_retry_sleep_millis = 10;
+// incremented on each flushpoint
+static u8 flushpoint_id = 0;
 
-class RotationLock : public StackObj {
+template <typename E, typename Instance, size_t(Instance::*func)()>
+class Content {
  private:
-  Thread* const _thread;
-  bool _acquired;
-
-  void log(bool recursion) {
-    assert(!_acquired, "invariant");
-    const char* error_msg = NULL;
-    if (recursion) {
-      error_msg = "Unable to issue rotation due to recursive calls.";
-    }
-    else {
-      error_msg = "Unable to issue rotation due to wait timeout.";
-    }
-    if (LogJFR) tty->print_cr( // For user, should not be "jfr, system"
-      "%s", error_msg);
+  Instance& _instance;
+  u4 _elements;
+ public:
+  typedef E EventType;
+  Content(Instance& instance) : _instance(instance), _elements(0) {}
+  bool process() {
+    _elements = (u4)(_instance.*func)();
+    return true;
   }
+  u4 elements() const { return _elements; }
+};
+
+template <typename Content>
+class WriteContent : public StackObj {
+ protected:
+  const JfrTicks _start_time;
+  JfrTicks _end_time;
+  JfrChunkWriter& _cw;
+  Content& _content;
+  const int64_t _start_offset;
  public:
-  RotationLock(Thread* thread) : _thread(thread), _acquired(false) {
-    assert(_thread != NULL, "invariant");
-    if (_thread == rotation_thread) {
-      // recursion not supported
-      log(true);
-      return;
-    }
+  typedef typename Content::EventType EventType;
 
-    // limited to not spin indefinitely
-    for (int i = 0; i < rotation_try_limit; ++i) {
-      if (try_set(_thread, &rotation_thread, false)) {
-        _acquired = true;
-        assert(_thread == rotation_thread, "invariant");
-        return;
-      }
-      if (_thread->is_Java_thread()) {
-        // in order to allow the system to move to a safepoint
-        MutexLockerEx msg_lock(JfrMsg_lock);
-        JfrMsg_lock->wait(false, rotation_retry_sleep_millis);
-      }
-      else {
-        os::naked_short_sleep(rotation_retry_sleep_millis);
-      }
-    }
-    log(false);
+  WriteContent(JfrChunkWriter& cw, Content& content) :
+    _start_time(JfrTicks::now()),
+    _end_time(),
+    _cw(cw),
+    _content(content),
+    _start_offset(_cw.current_offset()) {
+    assert(_cw.is_valid(), "invariant");
   }
 
-  ~RotationLock() {
-    assert(_thread != NULL, "invariant");
-    if (_acquired) {
-      assert(_thread == rotation_thread, "invariant");
-      while (!try_set(_thread, &rotation_thread, true));
-    }
+  bool process() {
+    // invocation
+    _content.process();
+    _end_time = JfrTicks::now();
+    return 0 != _content.elements();
+  }
+
+  const JfrTicks& start_time() const {
+    return _start_time;
+  }
+
+  const JfrTicks& end_time() const {
+    return _end_time;
+  }
+
+  int64_t start_offset() const {
+    return _start_offset;
+  }
+
+  int64_t end_offset() const {
+    return current_offset();
+  }
+
+  int64_t current_offset() const {
+    return _cw.current_offset();
+  }
+
+  u4 elements() const {
+    return (u4) _content.elements();
+  }
+
+  u4 size() const {
+    return (u4)(end_offset() - start_offset());
+  }
+
+  static bool is_event_enabled() {
+    return EventType::is_enabled();
+  }
+
+  static u8 event_id() {
+    return EventType::eventId;
+  }
+
+  void write_elements(int64_t offset) {
+    _cw.write_padded_at_offset<u4>(elements(), offset);
+  }
+
+  void write_size() {
+    _cw.write_padded_at_offset<u4>(size(), start_offset());
+  }
+
+  void set_last_checkpoint() {
+    _cw.set_last_checkpoint_offset(start_offset());
+  }
+
+  void rewind() {
+    _cw.seek(start_offset());
   }
-  bool not_acquired() const { return !_acquired; }
 };
 
+
 static intptr_t write_checkpoint_event_prologue(JfrChunkWriter& cw, u8 type_id) {
   const int64_t last_cp_offset = cw.last_checkpoint_offset();
   const int64_t delta_to_last_checkpoint = 0 == last_cp_offset ? 0 : last_cp_offset - cw.current_offset();
   cw.reserve(sizeof(u4));
   cw.write<u8>(EVENT_CHECKPOINT);
   cw.write(JfrTicks::now());
-  cw.write((int64_t)0); // duration
+  cw.write<u8>(0); // duration
   cw.write(delta_to_last_checkpoint);
-  cw.write<bool>(false); // flushpoint
-  cw.write<u4>((u4)1); // nof types in this checkpoint
+  cw.write<u4>(GENERIC); // checkpoint type
+  cw.write<u4>(1); // nof types in this checkpoint
   cw.write<u8>(type_id);
-  const intptr_t number_of_elements_offset = cw.current_offset();
-  cw.reserve(sizeof(u4));
-  return number_of_elements_offset;
+  return cw.reserve(sizeof(u4));
 }
 
-template <typename ContentFunctor>
-class WriteCheckpointEvent : public StackObj {
+template <typename Content>
+class WriteCheckpointEvent : public WriteContent<Content> {
  private:
-  JfrChunkWriter& _cw;
-  u8 _type_id;
-  ContentFunctor& _content_functor;
+  const u8 _type_id;
  public:
-  WriteCheckpointEvent(JfrChunkWriter& cw, u8 type_id, ContentFunctor& functor) :
-    _cw(cw),
-    _type_id(type_id),
-    _content_functor(functor) {
-    assert(_cw.is_valid(), "invariant");
-  }
+  WriteCheckpointEvent(JfrChunkWriter& cw, Content& content, u8 type_id) :
+    WriteContent<Content>(cw, content), _type_id(type_id) {}
+
   bool process() {
-    // current_cp_offset is also offset for the event size header field
-    const intptr_t current_cp_offset = _cw.current_offset();
-    const intptr_t num_elements_offset = write_checkpoint_event_prologue(_cw, _type_id);
-    // invocation
-    _content_functor.process();
-    const u4 number_of_elements = (u4)_content_functor.processed();
-    if (number_of_elements == 0) {
+    const int64_t num_elements_offset = write_checkpoint_event_prologue(this->_cw, _type_id);
+    if (!WriteContent<Content>::process()) {
       // nothing to do, rewind writer to start
-      _cw.seek(current_cp_offset);
-      return true;
+      this->rewind();
+      assert(this->current_offset() == this->start_offset(), "invariant");
+      return false;
     }
-    assert(number_of_elements > 0, "invariant");
-    assert(_cw.current_offset() > num_elements_offset, "invariant");
-    _cw.write_padded_at_offset<u4>(number_of_elements, num_elements_offset);
-    _cw.write_padded_at_offset<u4>((u4)_cw.current_offset() - current_cp_offset, current_cp_offset);
-    // update writer with last checkpoint position
-    _cw.set_last_checkpoint_offset(current_cp_offset);
+    assert(this->elements() > 0, "invariant");
+    assert(this->current_offset() > num_elements_offset, "invariant");
+    this->write_elements(num_elements_offset);
+    this->write_size();
+    this->set_last_checkpoint();
     return true;
   }
 };
 
-template <typename Instance, size_t(Instance::*func)()>
-class ServiceFunctor {
+template <typename Functor>
+static u4 invoke(Functor& f) {
+  f.process();
+  return f.elements();
+}
+
+template <typename Functor>
+static void write_flush_event(Functor& f) {
+  if (Functor::is_event_enabled()) {
+    typename Functor::EventType e(UNTIMED);
+    e.set_starttime(f.start_time());
+    e.set_endtime(f.end_time());
+    e.set_flushId(flushpoint_id);
+    e.set_elements(f.elements());
+    e.set_size(f.size());
+    e.commit();
+  }
+}
+
+template <typename Functor>
+static u4 invoke_with_flush_event(Functor& f) {
+  const u4 elements = invoke(f);
+  write_flush_event(f);
+  return elements;
+}
+
+class StackTraceRepository : public StackObj {
  private:
-  Instance& _instance;
-  size_t _processed;
+  JfrStackTraceRepository& _repo;
+  JfrChunkWriter& _cw;
+  size_t _elements;
+  bool _clear;
+
+ public:
+  typedef EventFlushStacktrace EventType;
+  StackTraceRepository(JfrStackTraceRepository& repo, JfrChunkWriter& cw, bool clear) :
+    _repo(repo), _cw(cw), _elements(0), _clear(clear) {}
+  bool process() {
+    _elements = _repo.write(_cw, _clear);
+    return true;
+  }
+  size_t elements() const { return _elements; }
+  void reset() { _elements = 0; }
+};
+
+typedef WriteCheckpointEvent<StackTraceRepository> WriteStackTrace;
+
+static u4 flush_stacktrace(JfrStackTraceRepository& stack_trace_repo, JfrChunkWriter& chunkwriter) {
+  StackTraceRepository str(stack_trace_repo, chunkwriter, false);
+  WriteStackTrace wst(chunkwriter, str, TYPE_STACKTRACE);
+  return invoke_with_flush_event(wst);
+}
+
+static u4 write_stacktrace(JfrStackTraceRepository& stack_trace_repo, JfrChunkWriter& chunkwriter, bool clear) {
+  StackTraceRepository str(stack_trace_repo, chunkwriter, clear);
+  WriteStackTrace wst(chunkwriter, str, TYPE_STACKTRACE);
+  return invoke(wst);
+}
+
+typedef Content<EventFlushStorage, JfrStorage, &JfrStorage::write> Storage;
+typedef WriteContent<Storage> WriteStorage;
+
+static size_t flush_storage(JfrStorage& storage, JfrChunkWriter& chunkwriter) {
+  assert(chunkwriter.is_valid(), "invariant");
+  Storage fsf(storage);
+  WriteStorage fs(chunkwriter, fsf);
+  return invoke_with_flush_event(fs);
+}
+
+static size_t write_storage(JfrStorage& storage, JfrChunkWriter& chunkwriter) {
+  assert(chunkwriter.is_valid(), "invariant");
+  Storage fsf(storage);
+  WriteStorage fs(chunkwriter, fsf);
+  return invoke(fs);
+}
+
+typedef Content<EventFlushStringPool, JfrStringPool, &JfrStringPool::write> StringPool;
+typedef Content<EventFlushStringPool, JfrStringPool, &JfrStringPool::write_at_safepoint> StringPoolSafepoint;
+typedef WriteCheckpointEvent<StringPool> WriteStringPool;
+typedef WriteCheckpointEvent<StringPoolSafepoint> WriteStringPoolSafepoint;
+
+static u4 flush_stringpool(JfrStringPool& string_pool, JfrChunkWriter& chunkwriter) {
+  StringPool sp(string_pool);
+  WriteStringPool wsp(chunkwriter, sp, TYPE_STRING);
+  return invoke_with_flush_event(wsp);
+}
+
+static u4 write_stringpool(JfrStringPool& string_pool, JfrChunkWriter& chunkwriter) {
+  StringPool sp(string_pool);
+  WriteStringPool wsp(chunkwriter, sp, TYPE_STRING);
+  return invoke(wsp);
+}
+
+static u4 write_stringpool_safepoint(JfrStringPool& string_pool, JfrChunkWriter& chunkwriter) {
+  StringPoolSafepoint sps(string_pool);
+  WriteStringPoolSafepoint wsps(chunkwriter, sps, TYPE_STRING);
+  return invoke(wsps);
+}
+
+typedef Content<EventFlushTypeSet, JfrCheckpointManager, &JfrCheckpointManager::flush_type_set> FlushTypeSetFunctor;
+typedef WriteContent<FlushTypeSetFunctor> FlushTypeSet;
+
+static u4 flush_typeset(JfrCheckpointManager& checkpoint_manager, JfrChunkWriter& chunkwriter) {
+  FlushTypeSetFunctor flush_type_set(checkpoint_manager);
+  FlushTypeSet fts(chunkwriter, flush_type_set);
+  return invoke_with_flush_event(fts);
+}
+
+class MetadataEvent : public StackObj {
+ private:
+  JfrChunkWriter& _cw;
  public:
-  ServiceFunctor(Instance& instance) : _instance(instance), _processed(0) {}
+  typedef EventFlushMetadata EventType;
+  MetadataEvent(JfrChunkWriter& cw) : _cw(cw) {}
   bool process() {
-    _processed = (_instance.*func)();
+    JfrMetadataEvent::write(_cw);
     return true;
   }
-  size_t processed() const { return _processed; }
+  size_t elements() const { return 1; }
 };
 
+typedef WriteContent<MetadataEvent> WriteMetadata;
+
+static u4 flush_metadata(JfrChunkWriter& chunkwriter) {
+  assert(chunkwriter.is_valid(), "invariant");
+  MetadataEvent me(chunkwriter);
+  WriteMetadata wm(chunkwriter, me);
+  return invoke_with_flush_event(wm);
+}
+
+static u4 write_metadata(JfrChunkWriter& chunkwriter) {
+  assert(chunkwriter.is_valid(), "invariant");
+  MetadataEvent me(chunkwriter);
+  WriteMetadata wm(chunkwriter, me);
+  return invoke(wm);
+}
+
 template <typename Instance, void(Instance::*func)()>
 class JfrVMOperation : public VM_Operation {
  private:
@@ -207,23 +341,13 @@ class JfrVMOperation : public VM_Operation {
   Mode evaluation_mode() const { return _safepoint; } // default
 };
 
-class WriteStackTraceRepository : public StackObj {
- private:
-  JfrStackTraceRepository& _repo;
-  JfrChunkWriter& _cw;
-  size_t _elements_processed;
-  bool _clear;
-
- public:
-  WriteStackTraceRepository(JfrStackTraceRepository& repo, JfrChunkWriter& cw, bool clear) :
-    _repo(repo), _cw(cw), _elements_processed(0), _clear(clear) {}
-  bool process() {
-    _elements_processed = _repo.write(_cw, _clear);
-    return true;
-  }
-  size_t processed() const { return _elements_processed; }
-  void reset() { _elements_processed = 0; }
-};
+JfrRecorderService::JfrRecorderService() :
+  _checkpoint_manager(JfrCheckpointManager::instance()),
+  _chunkwriter(JfrRepository::chunkwriter()),
+  _repository(JfrRepository::instance()),
+  _stack_trace_repository(JfrStackTraceRepository::instance()),
+  _storage(JfrStorage::instance()),
+  _string_pool(JfrStringPool::instance()) {}
 
 static bool recording = false;
 
@@ -236,19 +360,8 @@ bool JfrRecorderService::is_recording() {
   return recording;
 }
 
-JfrRecorderService::JfrRecorderService() :
-  _checkpoint_manager(JfrCheckpointManager::instance()),
-  _chunkwriter(JfrRepository::chunkwriter()),
-  _repository(JfrRepository::instance()),
-  _storage(JfrStorage::instance()),
-  _stack_trace_repository(JfrStackTraceRepository::instance()),
-  _string_pool(JfrStringPool::instance()) {}
-
 void JfrRecorderService::start() {
-  RotationLock rl(Thread::current());
-  if (rl.not_acquired()) {
-    return;
-  }
+  MutexLocker lock(JfrStream_lock);
   if (LogJFR) tty->print_cr("Request to START recording");
   assert(!is_recording(), "invariant");
   clear();
@@ -267,9 +380,9 @@ void JfrRecorderService::clear() {
 }
 
 void JfrRecorderService::pre_safepoint_clear() {
-  _stack_trace_repository.clear();
   _string_pool.clear();
   _storage.clear();
+  _stack_trace_repository.clear();
 }
 
 void JfrRecorderService::invoke_safepoint_clear() {
@@ -277,28 +390,28 @@ void JfrRecorderService::invoke_safepoint_clear() {
   VMThread::execute(&safepoint_task);
 }
 
-//
-// safepoint clear sequence
-//
-//  clear stacktrace repository ->
-//    clear string pool ->
-//      clear storage ->
-//        shift epoch ->
-//          update time
-//
 void JfrRecorderService::safepoint_clear() {
   assert(SafepointSynchronize::is_at_safepoint(), "invariant");
-  _stack_trace_repository.clear();
   _string_pool.clear();
   _storage.clear();
   _checkpoint_manager.shift_epoch();
-  _chunkwriter.time_stamp_chunk_now();
+  _chunkwriter.set_time_stamp();
+  _stack_trace_repository.clear();
 }
 
 void JfrRecorderService::post_safepoint_clear() {
   _checkpoint_manager.clear();
 }
 
+void JfrRecorderService::open_new_chunk(bool vm_error) {
+  JfrChunkRotation::on_rotation();
+  const bool valid_chunk = _repository.open_chunk(vm_error);
+  _storage.control().set_to_disk(valid_chunk);
+  if (valid_chunk) {
+    _checkpoint_manager.write_static_type_set_and_threads();
+  }
+}
+
 static void stop() {
   assert(JfrRecorderService::is_recording(), "invariant");
   if (LogJFR) tty->print_cr("Recording STOPPED");
@@ -306,11 +419,30 @@ static void stop() {
   assert(!JfrRecorderService::is_recording(), "invariant");
 }
 
-void JfrRecorderService::rotate(int msgs) {
-  RotationLock rl(Thread::current());
-  if (rl.not_acquired()) {
-    return;
+void JfrRecorderService::prepare_for_vm_error_rotation() {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
+  if (!_chunkwriter.is_valid()) {
+    open_new_chunk(true);
+  }
+  _checkpoint_manager.register_service_thread(Thread::current());
+}
+
+void JfrRecorderService::vm_error_rotation() {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
+  if (_chunkwriter.is_valid()) {
+    Thread* const t = Thread::current();
+    _storage.flush_regular_buffer(t->jfr_thread_local()->native_buffer(), t);
+    invoke_flush();
+    _chunkwriter.set_time_stamp();
+    _repository.close_chunk();
+    assert(!_chunkwriter.is_valid(), "invariant");
+    _repository.on_vm_error();
   }
+}
+
+void JfrRecorderService::rotate(int msgs) {
+  assert(!JfrStream_lock->owned_by_self(), "invariant");
+  MutexLocker lock(JfrStream_lock);
   static bool vm_error = false;
   if (msgs & MSGBIT(MSG_VM_ERROR)) {
     vm_error = true;
@@ -328,45 +460,19 @@ void JfrRecorderService::rotate(int msgs) {
   }
 }
 
-void JfrRecorderService::prepare_for_vm_error_rotation() {
-  if (!_chunkwriter.is_valid()) {
-    open_new_chunk(true);
-  }
-  _checkpoint_manager.register_service_thread(Thread::current());
-  JfrMetadataEvent::lock();
-}
-
-void JfrRecorderService::open_new_chunk(bool vm_error) {
-  assert(!_chunkwriter.is_valid(), "invariant");
-  assert(!JfrStream_lock->owned_by_self(), "invariant");
-  JfrChunkRotation::on_rotation();
-  MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
-  if (!_repository.open_chunk(vm_error)) {
-    assert(!_chunkwriter.is_valid(), "invariant");
-    _storage.control().set_to_disk(false);
-    return;
-  }
-  assert(_chunkwriter.is_valid(), "invariant");
-  _storage.control().set_to_disk(true);
-}
-
 void JfrRecorderService::in_memory_rotation() {
-  assert(!_chunkwriter.is_valid(), "invariant");
+  assert(JfrStream_lock->owned_by_self(), "invariant");
   // currently running an in-memory recording
+  assert(!_storage.control().to_disk(), "invariant");
   open_new_chunk();
   if (_chunkwriter.is_valid()) {
     // dump all in-memory buffer data to the newly created chunk
-    serialize_storage_from_in_memory_recording();
+    write_storage(_storage, _chunkwriter);
   }
 }
 
-void JfrRecorderService::serialize_storage_from_in_memory_recording() {
-  assert(!JfrStream_lock->owned_by_self(), "not holding stream lock!");
-  MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
-  _storage.write();
-}
-
 void JfrRecorderService::chunk_rotation() {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
   finalize_current_chunk();
   open_new_chunk();
 }
@@ -374,7 +480,6 @@ void JfrRecorderService::chunk_rotation() {
 void JfrRecorderService::finalize_current_chunk() {
   assert(_chunkwriter.is_valid(), "invariant");
   write();
-  assert(!_chunkwriter.is_valid(), "invariant");
 }
 
 void JfrRecorderService::write() {
@@ -385,54 +490,20 @@ void JfrRecorderService::write() {
   post_safepoint_write();
 }
 
-typedef ServiceFunctor<JfrStringPool, &JfrStringPool::write> WriteStringPool;
-typedef ServiceFunctor<JfrStringPool, &JfrStringPool::write_at_safepoint> WriteStringPoolSafepoint;
-typedef WriteCheckpointEvent<WriteStackTraceRepository> WriteStackTraceCheckpoint;
-typedef WriteCheckpointEvent<WriteStringPool> WriteStringPoolCheckpoint;
-typedef WriteCheckpointEvent<WriteStringPoolSafepoint> WriteStringPoolCheckpointSafepoint;
-
-static void write_stacktrace_checkpoint(JfrStackTraceRepository& stack_trace_repo, JfrChunkWriter& chunkwriter, bool clear) {
-  WriteStackTraceRepository write_stacktrace_repo(stack_trace_repo, chunkwriter, clear);
-  WriteStackTraceCheckpoint write_stack_trace_checkpoint(chunkwriter, TYPE_STACKTRACE, write_stacktrace_repo);
-  write_stack_trace_checkpoint.process();
-}
-static void write_stringpool_checkpoint(JfrStringPool& string_pool, JfrChunkWriter& chunkwriter) {
-  WriteStringPool write_string_pool(string_pool);
-  WriteStringPoolCheckpoint write_string_pool_checkpoint(chunkwriter, TYPE_STRING, write_string_pool);
-  write_string_pool_checkpoint.process();
-}
-
-static void write_stringpool_checkpoint_safepoint(JfrStringPool& string_pool, JfrChunkWriter& chunkwriter) {
-  WriteStringPoolSafepoint write_string_pool(string_pool);
-  WriteStringPoolCheckpointSafepoint write_string_pool_checkpoint(chunkwriter, TYPE_STRING, write_string_pool);
-  write_string_pool_checkpoint.process();
-}
-
-//
-// pre-safepoint write sequence
-//
-//  lock stream lock ->
-//    write non-safepoint dependent types ->
-//      write checkpoint epoch transition list->
-//        write stack trace checkpoint ->
-//          write string pool checkpoint ->
-//            write object sample stacktraces ->
-//              write storage ->
-//                release stream lock
-//
 void JfrRecorderService::pre_safepoint_write() {
-  MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
   assert(_chunkwriter.is_valid(), "invariant");
-  _checkpoint_manager.write_types();
-  _checkpoint_manager.write_epoch_transition_mspace();
-  write_stacktrace_checkpoint(_stack_trace_repository, _chunkwriter, false);
-  write_stringpool_checkpoint(_string_pool, _chunkwriter);
   if (LeakProfiler::is_running()) {
     // Exclusive access to the object sampler instance.
     // The sampler is released (unlocked) later in post_safepoint_write.
     ObjectSampleCheckpoint::on_rotation(ObjectSampler::acquire(), _stack_trace_repository);
   }
-  _storage.write();
+  if (_string_pool.is_modified()) {
+    write_stringpool(_string_pool, _chunkwriter);
+  }
+  write_storage(_storage, _chunkwriter);
+  if (_stack_trace_repository.is_modified()) {
+    write_stacktrace(_stack_trace_repository, _chunkwriter, false);
+  }
 }
 
 void JfrRecorderService::invoke_safepoint_write() {
@@ -440,50 +511,18 @@ void JfrRecorderService::invoke_safepoint_write() {
   VMThread::execute(&safepoint_task);
 }
 
-//
-// safepoint write sequence
-//
-//   lock stream lock ->
-//       write stacktrace repository ->
-//         write string pool ->
-//           write safepoint dependent types ->
-//             write storage ->
-//                 shift_epoch ->
-//                   update time ->
-//                     lock metadata descriptor ->
-//                       release stream lock
-//
 void JfrRecorderService::safepoint_write() {
   assert(SafepointSynchronize::is_at_safepoint(), "invariant");
-  MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
-  write_stacktrace_checkpoint(_stack_trace_repository, _chunkwriter, true);
-  write_stringpool_checkpoint_safepoint(_string_pool, _chunkwriter);
-  _checkpoint_manager.write_safepoint_types();
+  if (_string_pool.is_modified()) {
+    write_stringpool_safepoint(_string_pool, _chunkwriter);
+  }
+  _checkpoint_manager.on_rotation();
   _storage.write_at_safepoint();
   _checkpoint_manager.shift_epoch();
-  _chunkwriter.time_stamp_chunk_now();
-  JfrMetadataEvent::lock();
+  _chunkwriter.set_time_stamp();
+  write_stacktrace(_stack_trace_repository, _chunkwriter, true);
 }
 
-static jlong write_metadata_event(JfrChunkWriter& chunkwriter) {
-  assert(chunkwriter.is_valid(), "invariant");
-  const jlong metadata_offset = chunkwriter.current_offset();
-  JfrMetadataEvent::write(chunkwriter, metadata_offset);
-  return metadata_offset;
-}
-
-//
-// post-safepoint write sequence
-//
-//   write type set ->
-//     release object sampler ->
-//       lock stream lock ->
-//         write checkpoints ->
-//           write metadata event ->
-//             write chunk header ->
-//               close chunk fd ->
-//                 release stream lock
-//
 void JfrRecorderService::post_safepoint_write() {
   assert(_chunkwriter.is_valid(), "invariant");
   // During the safepoint tasks just completed, the system transitioned to a new epoch.
@@ -495,38 +534,85 @@ void JfrRecorderService::post_safepoint_write() {
     // The object sampler instance was exclusively acquired and locked in pre_safepoint_write.
     // Note: There is a dependency on write_type_set() above, ensure the release is subsequent.
     ObjectSampler::release();
-  }  MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
-  // serialize any outstanding checkpoint memory
-  _checkpoint_manager.write();
+  }
   // serialize the metadata descriptor event and close out the chunk
-  _repository.close_chunk(write_metadata_event(_chunkwriter));
-  assert(!_chunkwriter.is_valid(), "invariant");
+  write_metadata(_chunkwriter);
+  _repository.close_chunk();
 }
 
-void JfrRecorderService::vm_error_rotation() {
-  if (_chunkwriter.is_valid()) {
-    finalize_current_chunk_on_vm_error();
-    assert(!_chunkwriter.is_valid(), "invariant");
-    _repository.on_vm_error();
+static JfrBuffer* thread_local_buffer(Thread* t) {
+  assert(t != NULL, "invariant");
+  return t->jfr_thread_local()->native_buffer();
+}
+
+static void reset_buffer(JfrBuffer* buffer, Thread* t) {
+  assert(buffer != NULL, "invariant");
+  assert(t != NULL, "invariant");
+  assert(buffer == thread_local_buffer(t), "invariant");
+  buffer->set_pos(const_cast<u1*>(buffer->top()));
+}
+
+static void reset_thread_local_buffer(Thread* t) {
+  reset_buffer(thread_local_buffer(t), t);
+}
+
+static void write_thread_local_buffer(JfrChunkWriter& chunkwriter, Thread* t) {
+  JfrBuffer * const buffer = thread_local_buffer(t);
+  assert(buffer != NULL, "invariant");
+  if (!buffer->empty()) {
+    chunkwriter.write_unbuffered(buffer->top(), buffer->pos() - buffer->top());
+    reset_buffer(buffer, t);
   }
 }
 
-void JfrRecorderService::finalize_current_chunk_on_vm_error() {
+size_t JfrRecorderService::flush() {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
+  size_t total_elements = flush_metadata(_chunkwriter);
+  const size_t storage_elements = flush_storage(_storage, _chunkwriter);
+  if (0 == storage_elements) {
+    return total_elements;
+  }
+  total_elements += storage_elements;
+  if (_string_pool.is_modified()) {
+    total_elements += flush_stringpool(_string_pool, _chunkwriter);
+  }
+  if (_stack_trace_repository.is_modified()) {
+    total_elements += flush_stacktrace(_stack_trace_repository, _chunkwriter);
+  }
+  if (_checkpoint_manager.is_type_set_required()) {
+    total_elements += flush_typeset(_checkpoint_manager, _chunkwriter);
+  } else if (_checkpoint_manager.is_static_type_set_required()) {
+    // don't tally this, it is only in order to flush the waiting constants
+    _checkpoint_manager.flush_static_type_set();
+  }
+  return total_elements;
+}
+
+typedef Content<EventFlush, JfrRecorderService, &JfrRecorderService::flush> FlushFunctor;
+typedef WriteContent<FlushFunctor> Flush;
+
+void JfrRecorderService::invoke_flush() {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
   assert(_chunkwriter.is_valid(), "invariant");
-  pre_safepoint_write();
-  // Do not attempt safepoint dependent operations during emergency dump.
-  // Optimistically write tagged artifacts.
-  _checkpoint_manager.shift_epoch();
-  // update time
-  _chunkwriter.time_stamp_chunk_now();
-  post_safepoint_write();
-  assert(!_chunkwriter.is_valid(), "invariant");
+  Thread* const t = Thread::current();
+  ResourceMark rm(t);
+  HandleMark hm(t);
+  ++flushpoint_id;
+  reset_thread_local_buffer(t);
+  FlushFunctor flushpoint(*this);
+  Flush fl(_chunkwriter, flushpoint);
+  invoke_with_flush_event(fl);
+  write_thread_local_buffer(_chunkwriter, t);
+  _repository.flush_chunk();
+}
+
+void JfrRecorderService::flushpoint() {
+  MutexLocker lock(JfrStream_lock);
+  invoke_flush();
 }
 
 void JfrRecorderService::process_full_buffers() {
   if (_chunkwriter.is_valid()) {
-    assert(!JfrStream_lock->owned_by_self(), "invariant");
-    MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
     _storage.write_full();
   }
 }
diff --git a/src/share/vm/jfr/recorder/service/jfrRecorderService.hpp b/src/share/vm/jfr/recorder/service/jfrRecorderService.hpp
index 2cccf5b6f7d95de5224c0208bf0b3ff3bf65fdfe..d51444f3b8298303ea47056bba7af7ef23d0418f 100644
--- a/src/share/vm/jfr/recorder/service/jfrRecorderService.hpp
+++ b/src/share/vm/jfr/recorder/service/jfrRecorderService.hpp
@@ -46,11 +46,10 @@ class JfrRecorderService : public StackObj {
   void open_new_chunk(bool vm_error = false);
   void chunk_rotation();
   void in_memory_rotation();
-  void serialize_storage_from_in_memory_recording();
   void finalize_current_chunk();
-  void finalize_current_chunk_on_vm_error();
   void prepare_for_vm_error_rotation();
   void vm_error_rotation();
+  void invoke_flush();
 
   void clear();
   void pre_safepoint_clear();
@@ -67,7 +66,9 @@ class JfrRecorderService : public StackObj {
  public:
   JfrRecorderService();
   void start();
+  size_t flush();
   void rotate(int msgs);
+  void flushpoint();
   void process_full_buffers();
   void scavenge();
   void evaluate_chunk_size_for_rotation();
diff --git a/src/share/vm/jfr/recorder/service/jfrRecorderThread.cpp b/src/share/vm/jfr/recorder/service/jfrRecorderThread.cpp
index f6feb467467d3749620624a5ab9bea71842ac653..71470831823cbbe5c42d33c17a78fd18988ae41e 100644
--- a/src/share/vm/jfr/recorder/service/jfrRecorderThread.cpp
+++ b/src/share/vm/jfr/recorder/service/jfrRecorderThread.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -27,6 +27,7 @@
 #include "classfile/javaClasses.hpp"
 #include "classfile/symbolTable.hpp"
 #include "classfile/systemDictionary.hpp"
+#include "jfr/jfr.hpp"
 #include "jfr/jni/jfrJavaSupport.hpp"
 #include "jfr/recorder/jfrRecorder.hpp"
 #include "jfr/recorder/checkpoint/jfrCheckpointManager.hpp"
@@ -63,7 +64,6 @@ static Thread* start_thread(instanceHandle thread_oop, ThreadFunction proc, TRAP
   if (allocation_failed) {
     JfrJavaSupport::throw_out_of_memory_error("Unable to create native recording thread for JFR", CHECK_NULL);
   }
-
   Thread::start(new_thread);
   return new_thread;
 }
@@ -97,8 +97,9 @@ bool JfrRecorderThread::start(JfrCheckpointManager* cp_manager, JfrPostBox* post
   instanceHandle h_thread_oop(THREAD, (instanceOop)result.get_jobject());
   assert(h_thread_oop.not_null(), "invariant");
   // attempt thread start
-  const Thread* const t = start_thread(h_thread_oop, recorderthread_entry,THREAD);
+  Thread* const t = start_thread(h_thread_oop, recorderthread_entry,THREAD);
   if (!HAS_PENDING_EXCEPTION) {
+    Jfr::exclude_thread(t);
     cp_manager->register_service_thread(t);
     return true;
   }
diff --git a/src/share/vm/jfr/recorder/service/jfrRecorderThreadLoop.cpp b/src/share/vm/jfr/recorder/service/jfrRecorderThreadLoop.cpp
index fa766e2d6f2d001bdbed2b7297bf0f1e2a615de4..8f7723a64840cf7124a0826c67221bf9bde7d926 100644
--- a/src/share/vm/jfr/recorder/service/jfrRecorderThreadLoop.cpp
+++ b/src/share/vm/jfr/recorder/service/jfrRecorderThreadLoop.cpp
@@ -39,6 +39,7 @@ void recorderthread_entry(JavaThread* thread, Thread* unused) {
   #define START (msgs & (MSGBIT(MSG_START)))
   #define SHUTDOWN (msgs & MSGBIT(MSG_SHUTDOWN))
   #define ROTATE (msgs & (MSGBIT(MSG_ROTATE)|MSGBIT(MSG_STOP)))
+  #define FLUSHPOINT (msgs & (MSGBIT(MSG_FLUSHPOINT)))
   #define PROCESS_FULL_BUFFERS (msgs & (MSGBIT(MSG_ROTATE)|MSGBIT(MSG_STOP)|MSGBIT(MSG_FULLBUFFER)))
   #define SCAVENGE (msgs & (MSGBIT(MSG_DEADBUFFER)))
 
@@ -71,6 +72,8 @@ void recorderthread_entry(JavaThread* thread, Thread* unused) {
         service.start();
       } else if (ROTATE) {
         service.rotate(msgs);
+      } else if (FLUSHPOINT) {
+        service.flushpoint();
       }
       JfrMsg_lock->lock();
       post_box.notify_waiters();
@@ -89,6 +92,7 @@ void recorderthread_entry(JavaThread* thread, Thread* unused) {
   #undef START
   #undef SHUTDOWN
   #undef ROTATE
+  #undef FLUSHPOINT
   #undef PROCESS_FULL_BUFFERS
   #undef SCAVENGE
 }
diff --git a/src/share/vm/jfr/recorder/stacktrace/jfrStackTraceRepository.cpp b/src/share/vm/jfr/recorder/stacktrace/jfrStackTraceRepository.cpp
index f33ff914687863a543b59049bb0ecd2df8f25e15..1c24ecad3e7cd974c5df113798100b3e0aad7d12 100644
--- a/src/share/vm/jfr/recorder/stacktrace/jfrStackTraceRepository.cpp
+++ b/src/share/vm/jfr/recorder/stacktrace/jfrStackTraceRepository.cpp
@@ -62,7 +62,7 @@ class JfrFrameType : public JfrSerializer {
 };
 
 bool JfrStackTraceRepository::initialize() {
-  return JfrSerializer::register_serializer(TYPE_FRAMETYPE, false, true, new JfrFrameType());
+  return JfrSerializer::register_serializer(TYPE_FRAMETYPE, true, new JfrFrameType());
 }
 
 void JfrStackTraceRepository::destroy() {
@@ -71,7 +71,16 @@ void JfrStackTraceRepository::destroy() {
   _instance = NULL;
 }
 
-size_t JfrStackTraceRepository::write_impl(JfrChunkWriter& sw, bool clear) {
+static traceid last_id = 0;
+
+bool JfrStackTraceRepository::is_modified() const {
+  return last_id != _next_id;
+}
+
+size_t JfrStackTraceRepository::write(JfrChunkWriter& sw, bool clear) {
+  if (_entries == 0) {
+    return 0;
+  }
   MutexLockerEx lock(JfrStacktrace_lock, Mutex::_no_safepoint_check_flag);
   assert(_entries > 0, "invariant");
   int count = 0;
@@ -93,29 +102,10 @@ size_t JfrStackTraceRepository::write_impl(JfrChunkWriter& sw, bool clear) {
     memset(_table, 0, sizeof(_table));
     _entries = 0;
   }
+  last_id = _next_id;
   return count;
 }
 
-size_t JfrStackTraceRepository::write(JfrChunkWriter& sw, bool clear) {
-  return _entries > 0 ? write_impl(sw, clear) : 0;
-}
-
-traceid JfrStackTraceRepository::write(JfrCheckpointWriter& writer, traceid id, unsigned int hash) {
-  assert(JfrStacktrace_lock->owned_by_self(), "invariant");
-  const JfrStackTrace* const trace = lookup(hash, id);
-  assert(trace != NULL, "invariant");
-  assert(trace->hash() == hash, "invariant");
-  assert(trace->id() == id, "invariant");
-  trace->write(writer);
-  return id;
-}
-
-void JfrStackTraceRepository::write_metadata(JfrCheckpointWriter& writer) {
-  JfrFrameType fct;
-  writer.write_type(TYPE_FRAMETYPE);
-  fct.serialize(writer);
-}
-
 size_t JfrStackTraceRepository::clear() {
   MutexLockerEx lock(JfrStacktrace_lock, Mutex::_no_safepoint_check_flag);
   if (_entries == 0) {
@@ -142,7 +132,7 @@ traceid JfrStackTraceRepository::record(Thread* thread, int skip, StackWalkMode
   if (tl->has_cached_stack_trace()) {
     return tl->cached_stack_trace_id();
   }
-  if (!thread->is_Java_thread() || thread->is_hidden_from_external_view()) {
+  if (!thread->is_Java_thread() || thread->is_hidden_from_external_view() || tl->is_excluded()) {
     return 0;
   }
   JfrStackFrame* frames = tl->stackframes();
diff --git a/src/share/vm/jfr/recorder/stacktrace/jfrStackTraceRepository.hpp b/src/share/vm/jfr/recorder/stacktrace/jfrStackTraceRepository.hpp
index f17b92b79c378e4b66d306b2c3b6bfc6cf4bbec7..e9a9d62b6accb580726b890521c902bb65ce7fde 100644
--- a/src/share/vm/jfr/recorder/stacktrace/jfrStackTraceRepository.hpp
+++ b/src/share/vm/jfr/recorder/stacktrace/jfrStackTraceRepository.hpp
@@ -41,7 +41,7 @@ class JfrStackTraceRepository : public JfrCHeapObj {
   friend class ObjectSampleCheckpoint;
   friend class ObjectSampler;
   friend class StackTraceBlobInstaller;
-  friend class WriteStackTraceRepository;
+  friend class StackTraceRepository;
 
  private:
   static const u4 TABLE_SIZE = 2053;
@@ -52,19 +52,18 @@ class JfrStackTraceRepository : public JfrCHeapObj {
   JfrStackTraceRepository();
   static JfrStackTraceRepository& instance();
   static JfrStackTraceRepository* create();
-  bool initialize();
   static void destroy();
+  bool initialize();
 
-  size_t write_impl(JfrChunkWriter& cw, bool clear);
-  static void write_metadata(JfrCheckpointWriter& cpw);
-  traceid write(JfrCheckpointWriter& cpw, traceid id, unsigned int hash);
+  bool is_modified() const;
   size_t write(JfrChunkWriter& cw, bool clear);
   size_t clear();
 
+  const JfrStackTrace* lookup(unsigned int hash, traceid id) const;
+
   traceid add_trace(const JfrStackTrace& stacktrace);
   static traceid add(const JfrStackTrace& stacktrace);
   traceid record_for(JavaThread* thread, int skip, StackWalkMode mode, JfrStackFrame* frames, u4 max_frames);
-  const JfrStackTrace* lookup(unsigned int hash, traceid id) const;
 
  public:
   static traceid record(Thread* thread, int skip, StackWalkMode mode);
diff --git a/src/share/vm/jfr/recorder/storage/jfrBuffer.cpp b/src/share/vm/jfr/recorder/storage/jfrBuffer.cpp
index 120ea38c44943da10f34450870835d9d6dec948c..02ab10243a9ec7959a2c0ad157f4db8bd7c9e5ca 100644
--- a/src/share/vm/jfr/recorder/storage/jfrBuffer.cpp
+++ b/src/share/vm/jfr/recorder/storage/jfrBuffer.cpp
@@ -55,10 +55,18 @@ bool JfrBuffer::initialize(size_t header_size, size_t size, const void* id /* NU
   return true;
 }
 
-void JfrBuffer::reinitialize() {
+void JfrBuffer::reinitialize(bool exclusion /* false */) {
   assert(!lease(), "invariant");
   assert(!transient(), "invariant");
   set_pos(start());
+  if (exclusion != excluded()) {
+    // update
+    if (exclusion) {
+      set_excluded();
+    } else {
+      clear_excluded();
+    }
+  }
   clear_retired();
   set_top(start());
 }
@@ -191,7 +199,8 @@ void JfrBuffer::concurrent_move_and_reinitialize(JfrBuffer* const to, size_t siz
 enum FLAG {
   RETIRED = 1,
   TRANSIENT = 2,
-  LEASE = 4
+  LEASE = 4,
+  EXCLUDED = 8
 };
 
 bool JfrBuffer::transient() const {
@@ -250,3 +259,20 @@ void JfrBuffer::clear_retired() {
     release_store_flags(&_flags, new_flags);
   }
 }
+
+bool JfrBuffer::excluded() const {
+  return (u1)EXCLUDED == (_flags & (u1)EXCLUDED);
+}
+
+void JfrBuffer::set_excluded() {
+  _flags |= (u1)EXCLUDED;
+  assert(excluded(), "invariant");
+}
+
+void JfrBuffer::clear_excluded() {
+  if (excluded()) {
+    OrderAccess::storestore();
+    _flags ^= (u1)EXCLUDED;
+  }
+  assert(!excluded(), "invariant");
+}
diff --git a/src/share/vm/jfr/recorder/storage/jfrBuffer.hpp b/src/share/vm/jfr/recorder/storage/jfrBuffer.hpp
index f97d50fabae801623b25e4a762fc534afb029662..bee0bbe354090685a6ec79204acabdcb4bbe0a4d 100644
--- a/src/share/vm/jfr/recorder/storage/jfrBuffer.hpp
+++ b/src/share/vm/jfr/recorder/storage/jfrBuffer.hpp
@@ -61,7 +61,7 @@ class JfrBuffer {
  public:
   JfrBuffer();
   bool initialize(size_t header_size, size_t size, const void* id = NULL);
-  void reinitialize();
+  void reinitialize(bool exclusion = false);
   void concurrent_reinitialization();
   size_t discard();
   JfrBuffer* next() const {
@@ -167,6 +167,11 @@ class JfrBuffer {
   bool retired() const;
   void set_retired();
   void clear_retired();
+
+
+  bool excluded() const;
+  void set_excluded();
+  void clear_excluded();
 };
 
 class JfrAgeNode : public JfrBuffer {
diff --git a/src/share/vm/jfr/recorder/storage/jfrMemorySpace.hpp b/src/share/vm/jfr/recorder/storage/jfrMemorySpace.hpp
index b7aebed901c926901b3966ddb320de876f8dfe0c..ec4b8d5fb9166d1bc20d7f85ed7d77bd7944796b 100644
--- a/src/share/vm/jfr/recorder/storage/jfrMemorySpace.hpp
+++ b/src/share/vm/jfr/recorder/storage/jfrMemorySpace.hpp
@@ -99,8 +99,8 @@ class JfrMemorySpace : public JfrCHeapObj {
   template <typename IteratorCallback, typename IteratorType>
   void iterate(IteratorCallback& callback, bool full = true, jfr_iter_direction direction = forward);
 
-  debug_only(bool in_full_list(const Type* t) const { return _full.in_list(t); })
-  debug_only(bool in_free_list(const Type* t) const { return _free.in_list(t); })
+  bool in_full_list(const Type* t) const { return _full.in_list(t); }
+  bool in_free_list(const Type* t) const { return _free.in_list(t); }
 };
 
 #endif // SHARE_VM_JFR_RECORDER_STORAGE_JFRMEMORYSPACE_HPP
diff --git a/src/share/vm/jfr/recorder/storage/jfrMemorySpace.inline.hpp b/src/share/vm/jfr/recorder/storage/jfrMemorySpace.inline.hpp
index a55cee2d14b74d29f66952ac0743d28f3665b481..20285d7f6588da83fd64b1a76191243bdfe183c8 100644
--- a/src/share/vm/jfr/recorder/storage/jfrMemorySpace.inline.hpp
+++ b/src/share/vm/jfr/recorder/storage/jfrMemorySpace.inline.hpp
@@ -141,6 +141,7 @@ inline void JfrMemorySpace<T, RetrievalType, Callback>::release_free(T* t) {
   }
   assert(t->empty(), "invariant");
   assert(!t->retired(), "invariant");
+  assert(!t->excluded(), "invariant");
   assert(t->identity() == NULL, "invariant");
   if (!should_populate_cache()) {
     remove_free(t);
diff --git a/src/share/vm/jfr/recorder/storage/jfrStorage.cpp b/src/share/vm/jfr/recorder/storage/jfrStorage.cpp
index 23a106702a686ee676eab003fcbb7d541e5c6c1d..dff2b63b1777895803ee6c09b1b3f33ddcb80d6f 100644
--- a/src/share/vm/jfr/recorder/storage/jfrStorage.cpp
+++ b/src/share/vm/jfr/recorder/storage/jfrStorage.cpp
@@ -26,6 +26,7 @@
 #include "jfr/jfrEvents.hpp"
 #include "jfr/jni/jfrJavaSupport.hpp"
 #include "jfr/recorder/jfrRecorder.hpp"
+#include "jfr/recorder/checkpoint/jfrCheckpointManager.hpp"
 #include "jfr/recorder/repository/jfrChunkWriter.hpp"
 #include "jfr/recorder/service/jfrOptionSet.hpp"
 #include "jfr/recorder/service/jfrPostBox.hpp"
@@ -252,6 +253,18 @@ bool JfrStorage::flush_regular_buffer(BufferPtr buffer, Thread* thread) {
     assert(buffer->empty(), "invariant");
     return true;
   }
+
+  if (buffer->excluded()) {
+    const bool thread_is_excluded = thread->jfr_thread_local()->is_excluded();
+    buffer->reinitialize(thread_is_excluded);
+    assert(buffer->empty(), "invariant");
+    if (!thread_is_excluded) {
+      // state change from exclusion to inclusion requires a thread checkpoint
+      JfrCheckpointManager::write_thread_checkpoint(thread);
+    }
+    return true;
+  }
+
   BufferPtr const promotion_buffer = get_promotion_buffer(unflushed_size, _global_mspace, *this, promotion_retry, thread);
   if (promotion_buffer == NULL) {
     write_data_loss(buffer, thread);
@@ -302,7 +315,7 @@ static void handle_registration_failure(BufferPtr buffer) {
   assert(buffer != NULL, "invariant");
   assert(buffer->retired(), "invariant");
   const size_t unflushed_size = buffer->unflushed_size();
-  buffer->reinitialize();
+  buffer->concurrent_reinitialization();
   log_registration_failure(unflushed_size);
 }
 
@@ -464,6 +477,7 @@ static void assert_flush_large_precondition(ConstBufferPtr cur, const u1* const
   assert(t != NULL, "invariant");
   assert(cur != NULL, "invariant");
   assert(cur->lease(), "invariant");
+  assert(!cur->excluded(), "invariant");
   assert(cur_pos != NULL, "invariant");
   assert(native ? t->jfr_thread_local()->native_buffer() == cur : t->jfr_thread_local()->java_buffer() == cur, "invariant");
   assert(t->jfr_thread_local()->shelved_buffer() != NULL, "invariant");
@@ -490,6 +504,9 @@ BufferPtr JfrStorage::flush_regular(BufferPtr cur, const u1* const cur_pos, size
   // the case for stable thread local buffers; it is not the case for large buffers.
   if (!cur->empty()) {
     flush_regular_buffer(cur, t);
+    if (cur->excluded()) {
+      return cur;
+    }
   }
   assert(t->jfr_thread_local()->shelved_buffer() == NULL, "invariant");
   if (cur->free_size() >= req) {
@@ -578,28 +595,40 @@ BufferPtr JfrStorage::provision_large(BufferPtr cur, const u1* const cur_pos, si
 typedef UnBufferedWriteToChunk<JfrBuffer> WriteOperation;
 typedef MutexedWriteOp<WriteOperation> MutexedWriteOperation;
 typedef ConcurrentWriteOp<WriteOperation> ConcurrentWriteOperation;
-typedef ConcurrentWriteOpExcludeRetired<WriteOperation> ThreadLocalConcurrentWriteOperation;
+
+typedef Retired<JfrBuffer, true> NonRetired;
+typedef Excluded<JfrBuffer, true> NonExcluded;
+typedef CompositeOperation<NonRetired, NonExcluded> BufferPredicate;
+typedef PredicatedMutexedWriteOp<WriteOperation, BufferPredicate> ThreadLocalMutexedWriteOperation;
+typedef PredicatedConcurrentWriteOp<WriteOperation, BufferPredicate> ThreadLocalConcurrentWriteOperation;
 
 size_t JfrStorage::write() {
-  const size_t full_size_processed = write_full();
+  const size_t full_elements = write_full();
   WriteOperation wo(_chunkwriter);
-  ThreadLocalConcurrentWriteOperation tlwo(wo);
+  NonRetired nr;
+  NonExcluded ne;
+  BufferPredicate bp(&nr, &ne);
+  ThreadLocalConcurrentWriteOperation tlwo(wo, bp);
   process_full_list(tlwo, _thread_local_mspace);
   ConcurrentWriteOperation cwo(wo);
   process_free_list(cwo, _global_mspace);
-  return full_size_processed + wo.processed();
+  return full_elements + wo.elements();
 }
 
 size_t JfrStorage::write_at_safepoint() {
   assert(SafepointSynchronize::is_at_safepoint(), "invariant");
   WriteOperation wo(_chunkwriter);
   MutexedWriteOperation writer(wo); // mutexed write mode
-  process_full_list(writer, _thread_local_mspace);
+  NonRetired nr;
+  NonExcluded ne;
+  BufferPredicate bp(&nr, &ne);
+  ThreadLocalMutexedWriteOperation tlmwo(wo, bp);
+  process_full_list(tlmwo, _thread_local_mspace);
   assert(_transient_mspace->is_free_empty(), "invariant");
   process_full_list(writer, _transient_mspace);
   assert(_global_mspace->is_full_empty(), "invariant");
   process_free_list(writer, _global_mspace);
-  return wo.processed();
+  return wo.elements();
 }
 
 typedef DiscardOp<DefaultDiscarder<JfrStorage::Buffer> > DiscardOperation;
@@ -607,14 +636,14 @@ typedef ReleaseOp<JfrStorageMspace> ReleaseOperation;
 typedef CompositeOperation<MutexedWriteOperation, ReleaseOperation> FullOperation;
 
 size_t JfrStorage::clear() {
-  const size_t full_size_processed = clear_full();
+  const size_t full_elements = clear_full();
   DiscardOperation discarder(concurrent); // concurrent discard mode
   process_full_list(discarder, _thread_local_mspace);
   assert(_transient_mspace->is_free_empty(), "invariant");
   process_full_list(discarder, _transient_mspace);
   assert(_global_mspace->is_full_empty(), "invariant");
   process_free_list(discarder, _global_mspace);
-  return full_size_processed + discarder.processed();
+  return full_elements + discarder.elements();
 }
 
 static void insert_free_age_nodes(JfrStorageAgeMspace* age_mspace, JfrAgeNode* head, JfrAgeNode* tail, size_t count) {
@@ -703,15 +732,25 @@ size_t JfrStorage::write_full() {
   ReleaseOperation ro(_transient_mspace, thread);
   FullOperation cmd(&writer, &ro);
   const size_t count = process_full(cmd, control(), _age_mspace);
-  log(count, writer.processed());
-  return writer.processed();
+  if (0 == count) {
+    assert(0 == writer.elements(), "invariant");
+    return 0;
+  }
+  const size_t size = writer.size();
+  log(count, size);
+  return count;
 }
 
 size_t JfrStorage::clear_full() {
   DiscardOperation discarder(mutexed); // a retired buffer implies mutexed access
   const size_t count = process_full(discarder, control(), _age_mspace);
-  log(count, discarder.processed(), true);
-  return discarder.processed();
+  if (0 == count) {
+    assert(0 == discarder.elements(), "invariant");
+    return 0;
+  }
+  const size_t size = discarder.size();
+  log(count, size, true);
+  return count;
 }
 
 static void scavenge_log(size_t count, size_t amount, size_t current) {
@@ -739,6 +778,10 @@ public:
       assert(!t->lease(), "invariant");
       ++_count;
       _amount += t->total_size();
+      if (t->excluded()) {
+        t->clear_excluded();
+      }
+      assert(!t->excluded(), "invariant");
       t->clear_retired();
       t->release();
       _control.decrement_dead();
@@ -757,6 +800,11 @@ size_t JfrStorage::scavenge() {
   }
   Scavenger<JfrThreadLocalMspace> scavenger(ctrl, _thread_local_mspace);
   process_full_list(scavenger, _thread_local_mspace);
-  scavenge_log(scavenger.processed(), scavenger.amount(), ctrl.dead_count());
-  return scavenger.processed();
+  const size_t count = scavenger.processed();
+  if (0 == count) {
+    assert(0 == scavenger.amount(), "invariant");
+    return 0;
+  }
+  scavenge_log(count, scavenger.amount(), ctrl.dead_count());
+  return count;
 }
diff --git a/src/share/vm/jfr/recorder/storage/jfrStorage.hpp b/src/share/vm/jfr/recorder/storage/jfrStorage.hpp
index 90e0c90f65f2862e734148c489e1e851abe888d8..fb489a4c9c782cf787bad96420c3501ccb31490c 100644
--- a/src/share/vm/jfr/recorder/storage/jfrStorage.hpp
+++ b/src/share/vm/jfr/recorder/storage/jfrStorage.hpp
@@ -68,7 +68,6 @@ class JfrStorage : public JfrCHeapObj {
 
   size_t clear();
   size_t clear_full();
-  size_t write();
   size_t write_full();
   size_t write_at_safepoint();
   size_t scavenge();
@@ -89,6 +88,8 @@ class JfrStorage : public JfrCHeapObj {
   void discard_oldest(Thread* t);
   static JfrStorageControl& control();
 
+  size_t write();
+
   friend class JfrRecorder;
   friend class JfrRecorderService;
   template <typename, template <typename> class, typename>
diff --git a/src/share/vm/jfr/recorder/storage/jfrStorageControl.cpp b/src/share/vm/jfr/recorder/storage/jfrStorageControl.cpp
index 0a5db43c002751bfa8a563550e0a6671b0f77294..3a4591681e2648711014519249084ee639953403 100644
--- a/src/share/vm/jfr/recorder/storage/jfrStorageControl.cpp
+++ b/src/share/vm/jfr/recorder/storage/jfrStorageControl.cpp
@@ -33,7 +33,7 @@ static jlong atomic_add(size_t value, size_t volatile* const dest) {
   size_t compare_value;
   size_t exchange_value;
   do {
-    compare_value = OrderAccess::load_ptr_acquire((intptr_t*)dest);
+    compare_value = *dest;
     exchange_value = compare_value + value;
   } while ((unsigned long)Atomic::cmpxchg_ptr((intptr_t)exchange_value, (volatile intptr_t*)dest, (intptr_t)compare_value) != compare_value);
   return exchange_value;
@@ -43,7 +43,7 @@ static jlong atomic_dec(size_t volatile* const dest) {
   size_t compare_value;
   size_t exchange_value;
   do {
-    compare_value = OrderAccess::load_ptr_acquire((intptr_t*)dest);
+    compare_value = *dest;
     assert(compare_value >= 1, "invariant");
     exchange_value = compare_value - 1;
   } while ((unsigned long)Atomic::cmpxchg_ptr((intptr_t)exchange_value, (volatile intptr_t*)dest, (intptr_t)compare_value) != compare_value);
diff --git a/src/share/vm/jfr/recorder/storage/jfrStorageUtils.hpp b/src/share/vm/jfr/recorder/storage/jfrStorageUtils.hpp
index 1f4428da56ea7820b79a9dd0e9bcbc8a1bd486ad..bec28dcfc08fe8df70347682a3c9458dfb317b0a 100644
--- a/src/share/vm/jfr/recorder/storage/jfrStorageUtils.hpp
+++ b/src/share/vm/jfr/recorder/storage/jfrStorageUtils.hpp
@@ -31,7 +31,21 @@
 #include "jfr/utilities/jfrTypes.hpp"
 #include "runtime/thread.hpp"
 
-template <typename Operation, typename NextOperation>
+class CompositeOperationOr {
+ public:
+  static bool evaluate(bool value) {
+    return !value;
+  }
+};
+
+class CompositeOperationAnd {
+ public:
+  static bool evaluate(bool value) {
+    return value;
+  }
+};
+
+template <typename Operation, typename NextOperation, typename TruthFunction = CompositeOperationAnd>
 class CompositeOperation {
  private:
   Operation* _op;
@@ -41,11 +55,15 @@ class CompositeOperation {
     assert(_op != NULL, "invariant");
   }
   typedef typename Operation::Type Type;
-  bool process(Type* t = NULL) {
-    return _next == NULL ? _op->process(t) : _op->process(t) && _next->process(t);
+  bool process(Type* t) {
+    const bool op_result = _op->process(t);
+    return _next == NULL ? op_result : TruthFunction::evaluate(op_result) ? _next->process(t) : op_result;
   }
-  size_t processed() const {
-    return _next == NULL ? _op->processed() : _op->processed() + _next->processed();
+  size_t elements() const {
+    return _next == NULL ? _op->elements() : _op->elements() + _next->elements();
+  }
+  size_t size() const {
+    return _next == NULL ? _op->size() : _op->size() + _next->size();
   }
 };
 
@@ -53,54 +71,95 @@ template <typename T>
 class UnBufferedWriteToChunk {
  private:
   JfrChunkWriter& _writer;
-  size_t _processed;
+  size_t _elements;
+  size_t _size;
  public:
   typedef T Type;
-  UnBufferedWriteToChunk(JfrChunkWriter& writer) : _writer(writer), _processed(0) {}
+  UnBufferedWriteToChunk(JfrChunkWriter& writer) : _writer(writer), _elements(0), _size(0) {}
   bool write(Type* t, const u1* data, size_t size);
-  size_t processed() { return _processed; }
+  size_t elements() const { return _elements; }
+  size_t size() const { return _size; }
 };
 
 template <typename T>
 class DefaultDiscarder {
  private:
-  size_t _processed;
+  size_t _elements;
+  size_t _size;
  public:
   typedef T Type;
-  DefaultDiscarder() : _processed() {}
+  DefaultDiscarder() : _elements(0), _size(0) {}
   bool discard(Type* t, const u1* data, size_t size);
-  size_t processed() const { return _processed; }
+  size_t elements() const { return _elements; }
+  size_t size() const { return _size; }
+};
+
+template <typename T, bool negation>
+class Retired {
+ public:
+  typedef T Type;
+  bool process(Type* t) {
+    assert(t != NULL, "invariant");
+    return negation ? !t->retired() : t->retired();
+  }
+};
+
+template <typename T, bool negation>
+class Excluded {
+ public:
+  typedef T Type;
+  bool process(Type* t) {
+    assert(t != NULL, "invariant");
+    return negation ? !t->excluded() : t->excluded();
+  }
 };
 
 template <typename Operation>
-class ConcurrentWriteOp {
+class MutexedWriteOp {
  private:
   Operation& _operation;
  public:
   typedef typename Operation::Type Type;
-  ConcurrentWriteOp(Operation& operation) : _operation(operation) {}
+  MutexedWriteOp(Operation& operation) : _operation(operation) {}
   bool process(Type* t);
-  size_t processed() const { return _operation.processed(); }
+  size_t elements() const { return _operation.elements(); }
+  size_t size() const { return _operation.size(); }
 };
 
-template <typename Operation>
-class ConcurrentWriteOpExcludeRetired : private ConcurrentWriteOp<Operation> {
+template <typename Operation, typename Predicate>
+class PredicatedMutexedWriteOp : public MutexedWriteOp<Operation> {
+ private:
+  Predicate& _predicate;
  public:
-  typedef typename Operation::Type Type;
-  ConcurrentWriteOpExcludeRetired(Operation& operation) : ConcurrentWriteOp<Operation>(operation) {}
-  bool process(Type* t);
-  size_t processed() const { return ConcurrentWriteOp<Operation>::processed(); }
+  PredicatedMutexedWriteOp(Operation& operation, Predicate& predicate) :
+    MutexedWriteOp<Operation>(operation), _predicate(predicate) {}
+  bool process(typename Operation::Type* t) {
+    return _predicate.process(t) ? MutexedWriteOp<Operation>::process(t) : true;
+  }
 };
 
 template <typename Operation>
-class MutexedWriteOp {
+class ConcurrentWriteOp {
  private:
   Operation& _operation;
  public:
   typedef typename Operation::Type Type;
-  MutexedWriteOp(Operation& operation) : _operation(operation) {}
+  ConcurrentWriteOp(Operation& operation) : _operation(operation) {}
   bool process(Type* t);
-  size_t processed() const { return _operation.processed(); }
+  size_t elements() const { return _operation.elements(); }
+  size_t size() const { return _operation.size(); }
+};
+
+template <typename Operation, typename Predicate>
+class PredicatedConcurrentWriteOp : public ConcurrentWriteOp<Operation> {
+ private:
+  Predicate& _predicate;
+ public:
+  PredicatedConcurrentWriteOp(Operation& operation, Predicate& predicate) :
+    ConcurrentWriteOp<Operation>(operation), _predicate(predicate) {}
+  bool process(typename Operation::Type* t) {
+    return _predicate.process(t) ? ConcurrentWriteOp<Operation>::process(t) : true;
+  }
 };
 
 template <typename Operation>
@@ -126,7 +185,8 @@ class DiscardOp {
   typedef typename Operation::Type Type;
   DiscardOp(jfr_operation_mode mode = concurrent) : _operation(), _mode(mode) {}
   bool process(Type* t);
-  size_t processed() const { return _operation.processed(); }
+  size_t elements() const { return _operation.elements(); }
+  size_t size() const { return _operation.size(); }
 };
 
 #endif // SHARE_VM_JFR_RECORDER_STORAGE_JFRSTORAGEUTILS_HPP
diff --git a/src/share/vm/jfr/recorder/storage/jfrStorageUtils.inline.hpp b/src/share/vm/jfr/recorder/storage/jfrStorageUtils.inline.hpp
index 620a9f2614be33c978100f1bca2a399ddd81f9b8..919a1930dc2c8494728888be6c887cf781976acb 100644
--- a/src/share/vm/jfr/recorder/storage/jfrStorageUtils.inline.hpp
+++ b/src/share/vm/jfr/recorder/storage/jfrStorageUtils.inline.hpp
@@ -31,13 +31,15 @@
 template <typename T>
 inline bool UnBufferedWriteToChunk<T>::write(T* t, const u1* data, size_t size) {
   _writer.write_unbuffered(data, size);
-  _processed += size;
+  ++_elements;
+  _size += size;
   return true;
 }
 
 template <typename T>
 inline bool DefaultDiscarder<T>::discard(T* t, const u1* data, size_t size) {
-  _processed += size;
+  ++_elements;
+  _size += size;
   return true;
 }
 
@@ -54,15 +56,6 @@ inline bool ConcurrentWriteOp<Operation>::process(typename Operation::Type* t) {
   return result;
 }
 
-template <typename Operation>
-inline bool ConcurrentWriteOpExcludeRetired<Operation>::process(typename Operation::Type* t) {
-  if (t->retired()) {
-    assert(t->empty(), "invariant");
-    return true;
-  }
-  return ConcurrentWriteOp<Operation>::process(t);
-}
-
 template <typename Operation>
 inline bool MutexedWriteOp<Operation>::process(typename Operation::Type* t) {
   assert(t != NULL, "invariant");
diff --git a/src/share/vm/jfr/recorder/stringpool/jfrStringPool.cpp b/src/share/vm/jfr/recorder/stringpool/jfrStringPool.cpp
index 105089b050d1ce584b6b01cdcd4310e124f48148..cca2272438d7d7db2cae3015e0868737f180d1a9 100644
--- a/src/share/vm/jfr/recorder/stringpool/jfrStringPool.cpp
+++ b/src/share/vm/jfr/recorder/stringpool/jfrStringPool.cpp
@@ -32,7 +32,6 @@
 #include "jfr/recorder/stringpool/jfrStringPool.hpp"
 #include "jfr/recorder/stringpool/jfrStringPoolWriter.hpp"
 #include "jfr/utilities/jfrTypes.hpp"
-#include "runtime/atomic.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/orderAccess.hpp"
 #include "runtime/safepoint.hpp"
@@ -41,12 +40,42 @@
 typedef JfrStringPool::Buffer* BufferPtr;
 
 static JfrStringPool* _instance = NULL;
+static uint64_t store_generation = 0;
+static uint64_t serialized_generation = 0;
+
+inline void set_generation(uint64_t value, uint64_t* const dest) {
+  assert(dest != NULL, "invariant");
+  OrderAccess::release_store(dest, value);
+}
+static void increment_store_generation() {
+  const uint64_t current_serialized = OrderAccess::load_acquire(&serialized_generation);
+  const uint64_t current_stored = OrderAccess::load_acquire(&store_generation);
+  if (current_serialized == current_stored) {
+    set_generation(current_serialized + 1, &store_generation);
+  }
+}
+
+static bool increment_serialized_generation() {
+  const uint64_t current_stored = OrderAccess::load_acquire(&store_generation);
+  const uint64_t current_serialized = OrderAccess::load_acquire(&serialized_generation);
+  if (current_stored != current_serialized) {
+    set_generation(current_stored, &serialized_generation);
+    return true;
+  }
+  return false;
+}
+
+bool JfrStringPool::is_modified() {
+  return increment_serialized_generation();
+}
 
 JfrStringPool& JfrStringPool::instance() {
   return *_instance;
 }
 
 JfrStringPool* JfrStringPool::create(JfrChunkWriter& cw) {
+  store_generation = 0;
+  serialized_generation = 0;
   assert(_instance == NULL, "invariant");
   _instance = new JfrStringPool(cw);
   return _instance;
@@ -130,12 +159,16 @@ BufferPtr JfrStringPool::lease_buffer(Thread* thread, size_t size /* 0 */) {
 bool JfrStringPool::add(bool epoch, jlong id, jstring string, JavaThread* jt) {
   assert(jt != NULL, "invariant");
   const bool current_epoch = (JfrTraceIdEpoch::epoch() != 0);
-  if (current_epoch == epoch) {
+  if (current_epoch != epoch) {
+    return current_epoch;
+  }
+  {
     JfrStringPoolWriter writer(jt);
     writer.write(id);
     writer.write(string);
     writer.inc_nof_strings();
   }
+  increment_store_generation();
   return current_epoch;
 }
 
@@ -196,6 +229,7 @@ size_t JfrStringPool::write_at_safepoint() {
 }
 
 size_t JfrStringPool::clear() {
+  increment_serialized_generation();
   DiscardOperation discard_operation;
   ExclusiveDiscardOperation edo(discard_operation);
   StringPoolReleaseOperation spro(_free_list_mspace, Thread::current(), false);
diff --git a/src/share/vm/jfr/recorder/stringpool/jfrStringPool.hpp b/src/share/vm/jfr/recorder/stringpool/jfrStringPool.hpp
index 84c522174eff7d9f98c82691416919007d363754..fa27eb8e65cc26873201f729cec6d4377f719d4a 100644
--- a/src/share/vm/jfr/recorder/stringpool/jfrStringPool.hpp
+++ b/src/share/vm/jfr/recorder/stringpool/jfrStringPool.hpp
@@ -71,6 +71,7 @@ class JfrStringPool : public JfrCHeapObj {
   static JfrStringPool* create(JfrChunkWriter& cw);
   bool initialize();
   static void destroy();
+  static bool is_modified();
 
   friend class JfrRecorder;
   friend class JfrRecorderService;
diff --git a/src/share/vm/jfr/support/jfrThreadLocal.cpp b/src/share/vm/jfr/support/jfrThreadLocal.cpp
index 0d36e33f731bea88f392c5516f95376a2d21f17e..8d6ea9557296c36ae896d27dd0e8ce23a858a1e6 100644
--- a/src/share/vm/jfr/support/jfrThreadLocal.cpp
+++ b/src/share/vm/jfr/support/jfrThreadLocal.cpp
@@ -55,6 +55,7 @@ JfrThreadLocal::JfrThreadLocal() :
   _stack_trace_hash(0),
   _stackdepth(0),
   _entering_suspend_flag(0),
+  _excluded(false),
   _dead(false),
   _cached_top_frame_bci(max_jint),
   _alloc_count(0),
@@ -88,9 +89,13 @@ static void send_java_thread_start_event(JavaThread* jt) {
 void JfrThreadLocal::on_start(Thread* t) {
   assert(t != NULL, "invariant");
   assert(Thread::current() == t, "invariant");
+  JfrJavaSupport::on_thread_start(t);
   if (JfrRecorder::is_recording()) {
-    if (t->is_Java_thread()) {
-      send_java_thread_start_event((JavaThread*)t);
+    if (!t->jfr_thread_local()->is_excluded()) {
+      JfrCheckpointManager::write_thread_checkpoint(t);
+      if (t->is_Java_thread()) {
+        send_java_thread_start_event((JavaThread*)t);
+      }
     }
   }
 }
@@ -107,50 +112,68 @@ static void send_java_thread_end_events(traceid id, JavaThread* jt) {
   }
 }
 
+void JfrThreadLocal::release(Thread* t) {
+  if (has_java_event_writer()) {
+    assert(t->is_Java_thread(), "invariant");
+    JfrJavaSupport::destroy_global_jni_handle(java_event_writer());
+    _java_event_writer = NULL;
+  }
+  if (has_native_buffer()) {
+    JfrStorage::release_thread_local(native_buffer(), t);
+    _native_buffer = NULL;
+  }
+  if (has_java_buffer()) {
+    JfrStorage::release_thread_local(java_buffer(), t);
+    _java_buffer = NULL;
+  }
+  if (_stackframes != NULL) {
+    FREE_C_HEAP_ARRAY(JfrStackFrame, _stackframes, mtTracing);
+    _stackframes = NULL;
+  }
+}
+
 void JfrThreadLocal::release(JfrThreadLocal* tl, Thread* t) {
   assert(tl != NULL, "invariant");
   assert(t != NULL, "invariant");
   assert(Thread::current() == t, "invariant");
   assert(!tl->is_dead(), "invariant");
   assert(tl->shelved_buffer() == NULL, "invariant");
-  if (tl->has_native_buffer()) {
-    JfrStorage::release_thread_local(tl->native_buffer(), t);
-  }
-  if (tl->has_java_buffer()) {
-    JfrStorage::release_thread_local(tl->java_buffer(), t);
-  }
-  if (tl->has_java_event_writer()) {
-    assert(t->is_Java_thread(), "invariant");
-    JfrJavaSupport::destroy_global_jni_handle(tl->java_event_writer());
-  }
-  if (tl->_stackframes != NULL) {
-    FREE_C_HEAP_ARRAY(JfrStackFrame, tl->_stackframes, mtTracing);
-  }
   tl->_dead = true;
+  tl->release(t);
 }
 
 void JfrThreadLocal::on_exit(Thread* t) {
   assert(t != NULL, "invariant");
   JfrThreadLocal * const tl = t->jfr_thread_local();
   assert(!tl->is_dead(), "invariant");
-  if (t->is_Java_thread()) {
-    JavaThread* const jt = (JavaThread*)t;
-    ObjectSampleCheckpoint::on_thread_exit(jt);
-    send_java_thread_end_events(tl->thread_id(), jt);
+  if (JfrRecorder::is_recording()) {
+    if (t->is_Java_thread()) {
+      JavaThread* const jt = (JavaThread*)t;
+      ObjectSampleCheckpoint::on_thread_exit(jt);
+      send_java_thread_end_events(tl->thread_id(), jt);
+    }
   }
   release(tl, Thread::current()); // because it could be that Thread::current() != t
 }
 
+static JfrBuffer* acquire_buffer(bool excluded) {
+  JfrBuffer* const buffer = JfrStorage::acquire_thread_local(Thread::current());
+  if (buffer != NULL && excluded) {
+    buffer->set_excluded();
+  }
+  return buffer;
+}
+
 JfrBuffer* JfrThreadLocal::install_native_buffer() const {
   assert(!has_native_buffer(), "invariant");
-  _native_buffer = JfrStorage::acquire_thread_local(Thread::current());
+  _native_buffer = acquire_buffer(_excluded);
   return _native_buffer;
 }
 
 JfrBuffer* JfrThreadLocal::install_java_buffer() const {
   assert(!has_java_buffer(), "invariant");
   assert(!has_java_event_writer(), "invariant");
-  _java_buffer = JfrStorage::acquire_thread_local(Thread::current());
+  _java_buffer = acquire_buffer(_excluded);
   return _java_buffer;
 }
 
@@ -168,6 +191,18 @@ ByteSize JfrThreadLocal::java_event_writer_offset() {
   return in_ByteSize(offset_of(JfrThreadLocal, _java_event_writer));
 }
 
+void JfrThreadLocal::exclude(Thread* t) {
+  assert(t != NULL, "invariant");
+  t->jfr_thread_local()->_excluded = true;
+  t->jfr_thread_local()->release(t);
+}
+
+void JfrThreadLocal::include(Thread* t) {
+  assert(t != NULL, "invariant");
+  t->jfr_thread_local()->_excluded = false;
+  t->jfr_thread_local()->release(t);
+}
+
 u4 JfrThreadLocal::stackdepth() const {
   return _stackdepth != 0 ? _stackdepth : (u4)JfrOptionSet::stackdepth();
 }
diff --git a/src/share/vm/jfr/support/jfrThreadLocal.hpp b/src/share/vm/jfr/support/jfrThreadLocal.hpp
index 2684880ea7a770fb599c37b7912a45bc51484390..3c5292805c05d0742c91319a77aba2b5608a852e 100644
--- a/src/share/vm/jfr/support/jfrThreadLocal.hpp
+++ b/src/share/vm/jfr/support/jfrThreadLocal.hpp
@@ -50,6 +50,7 @@ class JfrThreadLocal {
   unsigned int _stack_trace_hash;
   mutable u4 _stackdepth;
   volatile jint _entering_suspend_flag;
+  bool _excluded;
   bool _dead;
   // Jfr callstack collection relies on vframeStream.
   // But the bci of top frame can not be determined by vframeStream in some scenarios.
@@ -76,7 +77,7 @@ class JfrThreadLocal {
   JfrBuffer* install_native_buffer() const;
   JfrBuffer* install_java_buffer() const;
   JfrStackFrame* install_stackframes() const;
-
+  void release(Thread* t);
   static void release(JfrThreadLocal* tl, Thread* t);
 
  public:
@@ -224,6 +225,10 @@ class JfrThreadLocal {
     _trace_id = id;
   }
 
+  bool is_excluded() const {
+    return _excluded;
+  }
+
   bool is_dead() const {
     return _dead;
   }
@@ -280,6 +285,9 @@ class JfrThreadLocal {
   void set_thread_blob(const JfrBlobHandle& handle);
   const JfrBlobHandle& thread_blob() const;
 
+  static void exclude(Thread* t);
+  static void include(Thread* t);
+
   static void on_start(Thread* t);
   static void on_exit(Thread* t);
 
diff --git a/src/share/vm/jfr/support/jfrTraceIdExtension.hpp b/src/share/vm/jfr/support/jfrTraceIdExtension.hpp
index 4464a94cd6cb898c6303559cde6c94027c6b39b7..05b5d6cf045e08a88530056e93d6233f086d24c3 100644
--- a/src/share/vm/jfr/support/jfrTraceIdExtension.hpp
+++ b/src/share/vm/jfr/support/jfrTraceIdExtension.hpp
@@ -61,8 +61,13 @@ class JfrTraceFlag {
   jbyte* flags_addr() const {
     return (jbyte*)&_flags;
   }
+
   jbyte* meta_addr() const {
+#ifdef VM_LITTLE_ENDIAN
     return ((jbyte*)&_flags) + 1;
+#else
+    return (jbyte*)&_flags;
+#endif
   }
 };
 
diff --git a/src/share/vm/jfr/utilities/jfrAllocation.cpp b/src/share/vm/jfr/utilities/jfrAllocation.cpp
index 2238bec5f6347eed2b330c09476acf7b0bd963b7..34521030fa119fc324d11d33c8cb588c8319ab0d 100644
--- a/src/share/vm/jfr/utilities/jfrAllocation.cpp
+++ b/src/share/vm/jfr/utilities/jfrAllocation.cpp
@@ -28,7 +28,6 @@
 #include "jfr/utilities/jfrTypes.hpp"
 #include "memory/allocation.inline.hpp"
 #include "runtime/atomic.inline.hpp"
-#include "runtime/orderAccess.inline.hpp"
 #include "runtime/vm_version.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "utilities/debug.hpp"
@@ -45,7 +44,7 @@ jlong atomic_add_jlong(jlong value, jlong volatile* const dest) {
   }
 #endif
   do {
-    compare_value = OrderAccess::load_acquire(dest);
+    compare_value = *dest;
     exchange_value = compare_value + value;
   } while (Atomic::cmpxchg(exchange_value, dest, compare_value) != compare_value);
   return exchange_value;
diff --git a/src/share/vm/jfr/utilities/jfrDoublyLinkedList.hpp b/src/share/vm/jfr/utilities/jfrDoublyLinkedList.hpp
index 8ecc326ff76a084151335f417e5aaba153abda5f..94e398acc72fdbfcacb65fd4a7b455b61b8b2688 100644
--- a/src/share/vm/jfr/utilities/jfrDoublyLinkedList.hpp
+++ b/src/share/vm/jfr/utilities/jfrDoublyLinkedList.hpp
@@ -48,8 +48,8 @@ class JfrDoublyLinkedList {
   void prepend(T* const node);
   void append(T* const node);
   void append_list(T* const head_node, T* const tail_node, size_t count);
-  debug_only(bool in_list(const T* const target_node) const;)
-  debug_only(bool locate(const T* start_node, const T* const target_node) const;)
+  bool in_list(const T* const target_node) const;
+  bool locate(const T* start_node, const T* const target_node) const;
 };
 
 template <typename T>
@@ -153,7 +153,6 @@ T* JfrDoublyLinkedList<T>::clear(bool return_tail /* false */) {
   return node;
 }
 
-#ifdef ASSERT
 template <typename T>
 bool JfrDoublyLinkedList<T>::locate(const T* node, const T* const target) const {
   assert(target != NULL, "invariant");
@@ -182,7 +181,6 @@ inline void validate_count_param(T* node, size_t count_param) {
   }
   assert(count_param == count, "invariant");
 }
-#endif // ASSERT
 
 template <typename T>
 void JfrDoublyLinkedList<T>::append_list(T* const head_node, T* const tail_node, size_t count) {
diff --git a/src/share/vm/jfr/utilities/jfrThreadIterator.cpp b/src/share/vm/jfr/utilities/jfrThreadIterator.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..4a50a9b6a67db087a5db6119bcab6d6ac46d1ad4
--- /dev/null
+++ b/src/share/vm/jfr/utilities/jfrThreadIterator.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "jfr/support/jfrThreadLocal.hpp"
+#include "jfr/utilities/jfrThreadIterator.hpp"
+#include "runtime/thread.inline.hpp"
+
+static bool thread_inclusion_predicate(Thread* t) {
+  assert(t != NULL, "invariant");
+  return !t->jfr_thread_local()->is_dead();
+}
+
+static bool java_thread_inclusion_predicate(JavaThread* jt) {
+  assert(jt != NULL, "invariant");
+  return thread_inclusion_predicate(jt) && jt->thread_state() != _thread_new;
+}
+
+static JavaThread* next_java_thread(JavaThread* cur) {
+  JavaThread* next = cur->next();
+  while (next != NULL && !java_thread_inclusion_predicate(next)) {
+    next = next->next();
+  }
+  return next;
+}
+
+/**
+static Thread* next_non_java_thread(Thread* cur) {
+  Thread* next = cur->next();
+  while (next != NULL && !thread_inclusion_predicate(next)) {
+    next = next->next();
+  }
+  return next;
+}
+*/
+
+JfrJavaThreadIteratorAdapter::JfrJavaThreadIteratorAdapter() {
+  _next = Threads::first();
+  while (_next != NULL && !java_thread_inclusion_predicate(_next)) {
+    _next = _next->next();
+  }
+}
+
+JavaThread* JfrJavaThreadIteratorAdapter::next() {
+  assert(has_next(), "invariant");
+  Type* const temp = _next;
+  _next = next_java_thread(_next);
+  assert(temp != _next, "invariant");
+  return temp;
+}
+
+JfrNonJavaThreadIteratorAdapter::JfrNonJavaThreadIteratorAdapter() {
+}
+
+bool JfrNonJavaThreadIteratorAdapter::has_next() const {
+  return false;
+}
+
+Thread* JfrNonJavaThreadIteratorAdapter::next() {
+  return NULL;
+}
+
+// explicit instantiations
+template class JfrThreadIterator<JfrJavaThreadIteratorAdapter, StackObj>;
+template class JfrThreadIterator<JfrNonJavaThreadIteratorAdapter, StackObj>;
diff --git a/src/share/vm/jfr/utilities/jfrThreadIterator.hpp b/src/share/vm/jfr/utilities/jfrThreadIterator.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..e89cbf2eddd483cfe6cfaad531f36abaea5c32bc
--- /dev/null
+++ b/src/share/vm/jfr/utilities/jfrThreadIterator.hpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_JFR_UTILITIES_JFRTHREADITERATOR_HPP
+#define SHARE_VM_JFR_UTILITIES_JFRTHREADITERATOR_HPP
+
+#include "memory/allocation.hpp"
+#include "runtime/thread.hpp"
+// #include "runtime/threadSMR.hpp"
+
+template <typename Adapter, typename AP = StackObj>
+class JfrThreadIterator : public AP {
+ private:
+  Adapter _adapter;
+ public:
+  JfrThreadIterator() : _adapter() {}
+  typename Adapter::Type* next() {
+    assert(has_next(), "invariant");
+    return _adapter.next();
+  }
+  bool has_next() const {
+    return _adapter.has_next();
+  }
+};
+
+class JfrJavaThreadIteratorAdapter {
+ private:
+  JavaThread* _next;
+ public:
+  typedef JavaThread Type;
+  JfrJavaThreadIteratorAdapter();
+  bool has_next() const {
+    return _next != NULL;
+  }
+  Type* next();
+};
+
+class JfrNonJavaThreadIteratorAdapter {
+ public:
+  typedef Thread Type;
+  JfrNonJavaThreadIteratorAdapter();
+  bool has_next() const;
+  Type* next();
+};
+
+typedef JfrThreadIterator<JfrJavaThreadIteratorAdapter, StackObj> JfrJavaThreadIterator;
+typedef JfrThreadIterator<JfrNonJavaThreadIteratorAdapter, StackObj> JfrNonJavaThreadIterator;
+
+#endif // SHARE_VM_JFR_UTILITIES_JFRTHREADITERATOR_HPP
diff --git a/src/share/vm/jfr/utilities/jfrTypes.hpp b/src/share/vm/jfr/utilities/jfrTypes.hpp
index da14db517f43f0d8fa08377df61dc4bfed39e9b2..91bf7464e0199fa0bc5f281b137fa835417d1f98 100644
--- a/src/share/vm/jfr/utilities/jfrTypes.hpp
+++ b/src/share/vm/jfr/utilities/jfrTypes.hpp
@@ -26,11 +26,14 @@
 #define SHARE_VM_JFR_UTILITIES_JFRTYPES_HPP
 
 #include "jfrfiles/jfrEventIds.hpp"
+#include "utilities/globalDefinitions.hpp"
 
 typedef u8 traceid;
 typedef int fio_fd;
+
 const int invalid_fd = -1;
 const jlong invalid_offset = -1;
+const int64_t invalid_time = -1;
 const u4 STACK_DEPTH_DEFAULT = 64;
 const u4 MIN_STACK_DEPTH = 1;
 const u4 MAX_STACK_DEPTH = 2048;
@@ -50,4 +53,12 @@ enum EventStartTime {
 
 jlong atomic_add_jlong(jlong value, jlong volatile* const dest);
 
+enum JfrCheckpointType {
+  GENERIC,
+  FLUSH,
+  HEADER,
+  STATICS = 4,
+  THREADS = 8
+};
+
 #endif // SHARE_VM_JFR_UTILITIES_JFRTYPES_HPP
diff --git a/src/share/vm/jfr/writers/jfrJavaEventWriter.hpp b/src/share/vm/jfr/writers/jfrJavaEventWriter.hpp
index 9e521f417a5b85f92cb668e3e1b7ece88b50c128..3dd3770e12318588a0e494c608a4eb6332d3f975 100644
--- a/src/share/vm/jfr/writers/jfrJavaEventWriter.hpp
+++ b/src/share/vm/jfr/writers/jfrJavaEventWriter.hpp
@@ -32,9 +32,9 @@ class JavaThread;
 class Thread;
 
 class JfrJavaEventWriter : AllStatic {
-  friend class JfrCheckpointThreadClosure;
-  friend class JfrJavaEventWriterNotificationClosure;
+  friend class JfrNotifyClosure;
   friend class JfrJavaEventWriterNotifyOperation;
+  friend class JfrJavaEventWriterNotificationClosure;
   friend class JfrRecorder;
  private:
   static bool initialize();
diff --git a/src/share/vm/jfr/writers/jfrStorageAdapter.hpp b/src/share/vm/jfr/writers/jfrStorageAdapter.hpp
index 1a47f5bb24bbc50ee32ef6b66c80c3a9a7528e47..24e7431aeaa947f11037f9955a7022580f32b832 100644
--- a/src/share/vm/jfr/writers/jfrStorageAdapter.hpp
+++ b/src/share/vm/jfr/writers/jfrStorageAdapter.hpp
@@ -82,7 +82,7 @@ class Adapter {
     assert(_thread != NULL, "invariant");
     Flush f(_storage, used, requested, _thread);
     _storage = f.result();
-    return _storage != NULL;
+    return _storage != NULL && !_storage->excluded();
   }
 
   void release() {
@@ -236,7 +236,8 @@ class NoOwnershipAdapter {
   void release() {}
   bool flush(size_t used, size_t requested) {
     // don't flush/expand a buffer that is not our own
-    return false;
+    _pos = _start;
+    return true;
   }
 };
 
diff --git a/src/share/vm/jfr/writers/jfrWriterHost.inline.hpp b/src/share/vm/jfr/writers/jfrWriterHost.inline.hpp
index 240632acc322b1e1269d0ea4f46459bfebc16452..cc97ddb4890f5f6e640f82703ebd269919dff155 100644
--- a/src/share/vm/jfr/writers/jfrWriterHost.inline.hpp
+++ b/src/share/vm/jfr/writers/jfrWriterHost.inline.hpp
@@ -114,10 +114,7 @@ void WriterHost<BE, IE, WriterPolicyImpl>::write_utf16(const jchar* value, jint
 template <typename BE, typename IE, typename WriterPolicyImpl >
 template <typename T>
 inline void WriterHost<BE, IE, WriterPolicyImpl>::be_write(T value) {
-  u1* const pos = ensure_size(sizeof(T));
-  if (pos) {
-    this->set_current_pos(BE::be_write(&value, 1, pos));
-  }
+  be_write(&value, 1);
 }
 
 template <typename BE, typename IE, typename WriterPolicyImpl >
diff --git a/src/share/vm/runtime/mutexLocker.cpp b/src/share/vm/runtime/mutexLocker.cpp
index 7cb2f08c415c828e6df4f33c96b37c6b4f2aa9d6..3c24e8386ba28738a2c6b046657f7c7af008570b 100644
--- a/src/share/vm/runtime/mutexLocker.cpp
+++ b/src/share/vm/runtime/mutexLocker.cpp
@@ -334,7 +334,7 @@ void mutex_init() {
   def(JfrMsg_lock                  , Monitor, leaf,        true);
   def(JfrBuffer_lock               , Mutex,   leaf,        true);
   def(JfrThreadGroups_lock         , Mutex,   leaf,        true);
-  def(JfrStream_lock               , Mutex,   nonleaf,     true);
+  def(JfrStream_lock               , Mutex,   nonleaf + 1, false);
   def(JfrStacktrace_lock           , Mutex,   special,     true);
 
 #ifndef SUPPORTS_NATIVE_CX8
diff --git a/src/share/vm/runtime/semaphore.inline.hpp b/src/share/vm/runtime/semaphore.inline.hpp
index e1cd4c9f6e7b8df78322c8b1c67900db57a5f014..458bfca8014ebf2e3f8a9c9f46afeb910ea70ca5 100644
--- a/src/share/vm/runtime/semaphore.inline.hpp
+++ b/src/share/vm/runtime/semaphore.inline.hpp
@@ -25,7 +25,7 @@
 #ifndef SHARE_VM_RUNTIME_SEMAPHORE_INLINE_HPP
 #define SHARE_VM_RUNTIME_SEMAPHORE_INLINE_HPP
 
-#include "runtime/interfaceSupport.inline.hpp"
+#include "runtime/interfaceSupport.hpp"
 #include "runtime/semaphore.hpp"
 #include "runtime/thread.inline.hpp"