7194254: jstack reports wrong thread priorities

Reviewed-by: dholmes, sla, fparain
Contributed-by: NDmytro Sheyko <dmytro_sheyko@hotmail.com>

src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.cpp

@@ -230,6 +230,7 @@ void ConcurrentMarkSweepThread::print_on(outputStream* st) const {
 void ConcurrentMarkSweepThread::print_all_on(outputStream* st) {
   if (_cmst != NULL) {
     _cmst->print_on(st);
+    st->cr();
   }
   if (_collector != NULL) {
     AbstractWorkGang* gang = _collector->conc_workers();

src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp

@@ -3420,7 +3420,6 @@ void G1CollectedHeap::print_gc_threads_on(outputStream* st) const {
   st->cr();
   _cm->print_worker_threads_on(st);
   _cg1r->print_worker_threads_on(st);
-  st->cr();
 }
 
 void G1CollectedHeap::gc_threads_do(ThreadClosure* tc) const {

src/share/vm/runtime/os.cpp

@@ -201,14 +201,21 @@ OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
   }
 }
 
-
+// The mapping from OS priority back to Java priority may be inexact because
+// Java priorities can map M:1 with native priorities. If you want the definite
+// Java priority then use JavaThread::java_priority()
 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
   int p;
   int os_prio;
   OSReturn ret = get_native_priority(thread, &os_prio);
   if (ret != OS_OK) return ret;
 
+  if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
+  } else {
+    // niceness values are in reverse order
+    for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
+  }
   priority = (ThreadPriority)p;
   return OS_OK;
 }

src/share/vm/runtime/thread.cpp

@@ -836,7 +836,11 @@ void Thread::metadata_do(void f(Metadata*)) {
 void Thread::print_on(outputStream* st) const {
   // get_priority assumes osthread initialized
   if (osthread() != NULL) {
-    st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
+    int os_prio;
+    if (os::get_native_priority(this, &os_prio) == OS_OK) {
+      st->print("os_prio=%d ", os_prio);
+    }
+    st->print("tid=" INTPTR_FORMAT " ", this);
     osthread()->print_on(st);
   }
   debug_only(if (WizardMode) print_owned_locks_on(st);)
@@ -2743,7 +2747,11 @@ void JavaThread::print_thread_state() const {
 void JavaThread::print_on(outputStream *st) const {
   st->print("\"%s\" ", get_thread_name());
   oop thread_oop = threadObj();
-  if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
+  if (thread_oop != NULL) {
+    st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
+    if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
+    st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
+  }
   Thread::print_on(st);
   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
@@ -4270,8 +4278,10 @@ void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format
   st->cr();
   Universe::heap()->print_gc_threads_on(st);
   WatcherThread* wt = WatcherThread::watcher_thread();
-  if (wt != NULL) wt->print_on(st);
+  if (wt != NULL) {
+    wt->print_on(st);
     st->cr();
+  }
   CompileBroker::print_compiler_threads_on(st);
   st->flush();
 }

test/runtime/7194254/Test7194254.java

+/*
+ * Copyright (c) 2012, 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.
+ */
+
+/*
+ * @test
+ * @bug     7194254
+ * @summary Creates several threads with different java priorities and checks
+ *      whether jstack reports correct priorities for them.
+ *
+ * @run main T7194254
+ */
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.lang.management.ManagementFactory;
+import java.lang.management.RuntimeMXBean;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CyclicBarrier;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class Test7194254 {
+
+    public static void main(String[] args) throws Exception {
+        final int NUMBER_OF_JAVA_PRIORITIES =
+                Thread.MAX_PRIORITY - Thread.MIN_PRIORITY + 1;
+        final CyclicBarrier barrier =
+                new CyclicBarrier(NUMBER_OF_JAVA_PRIORITIES + 1);
+
+        for (int p = Thread.MIN_PRIORITY; p <= Thread.MAX_PRIORITY; ++p) {
+            final int priority = p;
+            new Thread("Priority=" + p) {
+                {
+                    setPriority(priority);
+                }
+                public void run() {
+                    try {
+                        barrier.await(); // 1st
+                        barrier.await(); // 2nd
+                    } catch (Exception exc) {
+                        // ignore
+                    }
+                }
+            }.start();
+        }
+        barrier.await(); // 1st
+
+        int matches = 0;
+        List<String> failed = new ArrayList<>();
+        try {
+            String pid = getPid();
+            String jstack = System.getProperty("java.home") + "/../bin/jstack";
+            Process process = new ProcessBuilder(jstack, pid)
+                    .redirectErrorStream(true).start();
+            Pattern pattern = Pattern.compile(
+                    "\\\"Priority=(\\d+)\\\".* prio=(\\d+).*");
+            try (BufferedReader reader = new BufferedReader(
+                    new InputStreamReader(process.getInputStream()))) {
+                String line;
+                while((line = reader.readLine()) != null) {
+                    Matcher matcher = pattern.matcher(line);
+                    if (matcher.matches()) {
+                        matches += 1;
+                        String expected = matcher.group(1);
+                        String actual = matcher.group(2);
+                        if (!expected.equals(actual)) {
+                            failed.add(line);
+                        }
+                    }
+                }
+            }
+            barrier.await(); // 2nd
+        } finally {
+            barrier.reset();
+        }
+
+        if (matches != NUMBER_OF_JAVA_PRIORITIES) {
+            throw new AssertionError("matches: expected " +
+                    NUMBER_OF_JAVA_PRIORITIES + ", but was " + matches);
+        }
+        if (!failed.isEmpty()) {
+            throw new AssertionError(failed.size() + ":" + failed);
+        }
+        System.out.println("Test passes.");
+    }
+
+    static String getPid() {
+        RuntimeMXBean runtimebean = ManagementFactory.getRuntimeMXBean();
+        String vmname = runtimebean.getName();
+        int i = vmname.indexOf('@');
+        if (i != -1) {
+            vmname = vmname.substring(0, i);
+        }
+        return vmname;
+    }
+
+}
+