Merge

src/cpu/sparc/vm/vm_version_sparc.cpp

@@ -106,10 +106,10 @@ void VM_Version::initialize() {
     if (FLAG_IS_DEFAULT(OptoLoopAlignment)) {
       FLAG_SET_DEFAULT(OptoLoopAlignment, 4);
     }
-    // When using CMS, we cannot use memset() in BOT updates because
-    // the sun4v/CMT version in libc_psr uses BIS which exposes
-    // "phantom zeros" to concurrent readers. See 6948537.
-    if (FLAG_IS_DEFAULT(UseMemSetInBOT) && UseConcMarkSweepGC) {
+    // When using CMS or G1, we cannot use memset() in BOT updates
+    // because the sun4v/CMT version in libc_psr uses BIS which
+    // exposes "phantom zeros" to concurrent readers. See 6948537.
+    if (FLAG_IS_DEFAULT(UseMemSetInBOT) && (UseConcMarkSweepGC || UseG1GC)) {
       FLAG_SET_DEFAULT(UseMemSetInBOT, false);
     }
 #ifdef _LP64

src/share/vm/gc_implementation/g1/g1BlockOffsetTable.hpp

 /*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 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
@@ -159,14 +159,30 @@ private:
            "right address out of range");
     assert(left  < right, "Heap addresses out of order");
     size_t num_cards = pointer_delta(right, left) >> LogN_words;
-    memset(&_offset_array[index_for(left)], offset, num_cards);
+    if (UseMemSetInBOT) {
+      memset(&_offset_array[index_for(left)], offset, num_cards);
+    } else {
+      size_t i = index_for(left);
+      const size_t end = i + num_cards;
+      for (; i < end; i++) {
+        _offset_array[i] = offset;
+      }
+    }
   }
 
   void set_offset_array(size_t left, size_t right, u_char offset) {
     assert(right < _vs.committed_size(), "right address out of range");
-    assert(left  <= right, "indexes out of order");
+    assert(left <= right, "indexes out of order");
     size_t num_cards = right - left + 1;
-    memset(&_offset_array[left], offset, num_cards);
+    if (UseMemSetInBOT) {
+      memset(&_offset_array[left], offset, num_cards);
+    } else {
+      size_t i = left;
+      const size_t end = i + num_cards;
+      for (; i < end; i++) {
+        _offset_array[i] = offset;
+      }
+    }
   }
 
   void check_offset_array(size_t index, HeapWord* high, HeapWord* low) const {

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

@@ -1934,6 +1934,14 @@ G1CollectedHeap::G1CollectedHeap(G1CollectorPolicy* policy_) :
   clear_cset_start_regions();
 
   guarantee(_task_queues != NULL, "task_queues allocation failure.");
+#ifdef SPARC
+  // Issue a stern warning, but allow use for experimentation and debugging.
+  if (VM_Version::is_sun4v() && UseMemSetInBOT) {
+    assert(!FLAG_IS_DEFAULT(UseMemSetInBOT), "Error");
+    warning("Experimental flag -XX:+UseMemSetInBOT is known to cause instability"
+            " on sun4v; please understand that you are using at your own risk!");
+  }
+#endif
 }
 
 jint G1CollectedHeap::initialize() {
@@ -3582,15 +3590,11 @@ size_t G1CollectedHeap::pending_card_num() {
   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
   size_t buffer_size = dcqs.buffer_size();
   size_t buffer_num = dcqs.completed_buffers_num();
-  return buffer_size * buffer_num + extra_cards;
-}
 
-size_t G1CollectedHeap::max_pending_card_num() {
-  DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
-  size_t buffer_size = dcqs.buffer_size();
-  size_t buffer_num  = dcqs.completed_buffers_num();
-  int thread_num  = Threads::number_of_threads();
-  return (buffer_num + thread_num) * buffer_size;
+  // PtrQueueSet::buffer_size() and PtrQueue:size() return sizes
+  // in bytes - not the number of 'entries'. We need to convert
+  // into a number of cards.
+  return (buffer_size * buffer_num + extra_cards) / oopSize;
 }
 
 size_t G1CollectedHeap::cards_scanned() {

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

@@ -1706,7 +1706,6 @@ public:
   void stop_conc_gc_threads();
 
   size_t pending_card_num();
-  size_t max_pending_card_num();
   size_t cards_scanned();
 
 protected:

src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp

@@ -90,7 +90,6 @@ G1CollectorPolicy::G1CollectorPolicy() :
 
   _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   _prev_collection_pause_end_ms(0.0),
-  _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
   _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
   _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
@@ -197,7 +196,6 @@ G1CollectorPolicy::G1CollectorPolicy() :
 
   int index = MIN2(_parallel_gc_threads - 1, 7);
 
-  _pending_card_diff_seq->add(0.0);
   _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
   _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
   _young_cards_per_entry_ratio_seq->add(
@@ -657,7 +655,7 @@ double G1CollectorPolicy::predict_survivor_regions_evac_time() {
   for (HeapRegion * r = _recorded_survivor_head;
        r != NULL && r != _recorded_survivor_tail->get_next_young_region();
        r = r->get_next_young_region()) {
-    survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
+    survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young());
   }
   return survivor_regions_evac_time;
 }
@@ -801,9 +799,8 @@ void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
   _cur_collection_pause_used_at_start_bytes = start_used;
   _cur_collection_pause_used_regions_at_start = _g1->used_regions();
   _pending_cards = _g1->pending_card_num();
-  _max_pending_cards = _g1->max_pending_card_num();
 
-  _bytes_in_collection_set_before_gc = 0;
+  _collection_set_bytes_used_before = 0;
   _bytes_copied_during_gc = 0;
 
   YoungList* young_list = _g1->young_list();
@@ -1036,12 +1033,6 @@ void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms) {
   // do that for any other surv rate groupsx
 
   if (update_stats) {
-    size_t diff = 0;
-    if (_max_pending_cards >= _pending_cards) {
-      diff = _max_pending_cards - _pending_cards;
-    }
-    _pending_card_diff_seq->add((double) diff);
-
     double cost_per_card_ms = 0.0;
     if (_pending_cards > 0) {
       cost_per_card_ms = phase_times()->_update_rs_time / (double) _pending_cards;
@@ -1126,9 +1117,9 @@ void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms) {
     _constant_other_time_ms_seq->add(constant_other_time_ms);
 
     double survival_ratio = 0.0;
-    if (_bytes_in_collection_set_before_gc > 0) {
+    if (_collection_set_bytes_used_before > 0) {
       survival_ratio = (double) _bytes_copied_during_gc /
-                                   (double) _bytes_in_collection_set_before_gc;
+                                   (double) _collection_set_bytes_used_before;
     }
 
     _pending_cards_seq->add((double) _pending_cards);
@@ -1228,6 +1219,15 @@ void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
   dcqs.notify_if_necessary();
 }
 
+double
+G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
+                                                size_t scanned_cards) {
+  return
+    predict_rs_update_time_ms(pending_cards) +
+    predict_rs_scan_time_ms(scanned_cards) +
+    predict_constant_other_time_ms();
+}
+
 double
 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
   size_t rs_length = predict_rs_length_diff();
@@ -1240,21 +1240,28 @@ G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
   return predict_base_elapsed_time_ms(pending_cards, card_num);
 }
 
-double
-G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
-                                                size_t scanned_cards) {
-  return
-    predict_rs_update_time_ms(pending_cards) +
-    predict_rs_scan_time_ms(scanned_cards) +
-    predict_constant_other_time_ms();
+size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
+  size_t bytes_to_copy;
+  if (hr->is_marked())
+    bytes_to_copy = hr->max_live_bytes();
+  else {
+    assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
+    int age = hr->age_in_surv_rate_group();
+    double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
+    bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
+  }
+  return bytes_to_copy;
 }
 
 double
 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
-                                                  bool young) {
+                                                  bool for_young_gc) {
   size_t rs_length = hr->rem_set()->occupied();
   size_t card_num;
-  if (gcs_are_young()) {
+
+  // Predicting the number of cards is based on which type of GC
+  // we're predicting for.
+  if (for_young_gc) {
     card_num = predict_young_card_num(rs_length);
   } else {
     card_num = predict_non_young_card_num(rs_length);
@@ -1265,25 +1272,14 @@ G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
     predict_rs_scan_time_ms(card_num) +
     predict_object_copy_time_ms(bytes_to_copy);
 
-  if (young)
+  // The prediction of the "other" time for this region is based
+  // upon the region type and NOT the GC type.
+  if (hr->is_young()) {
     region_elapsed_time_ms += predict_young_other_time_ms(1);
-  else
+  } else {
     region_elapsed_time_ms += predict_non_young_other_time_ms(1);
-
-  return region_elapsed_time_ms;
-}
-
-size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
-  size_t bytes_to_copy;
-  if (hr->is_marked())
-    bytes_to_copy = hr->max_live_bytes();
-  else {
-    assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
-    int age = hr->age_in_surv_rate_group();
-    double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
-    bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
   }
-  return bytes_to_copy;
+  return region_elapsed_time_ms;
 }
 
 void
@@ -1342,22 +1338,6 @@ size_t G1CollectorPolicy::expansion_amount() {
   }
 }
 
-class CountCSClosure: public HeapRegionClosure {
-  G1CollectorPolicy* _g1_policy;
-public:
-  CountCSClosure(G1CollectorPolicy* g1_policy) :
-    _g1_policy(g1_policy) {}
-  bool doHeapRegion(HeapRegion* r) {
-    _g1_policy->_bytes_in_collection_set_before_gc += r->used();
-    return false;
-  }
-};
-
-void G1CollectorPolicy::count_CS_bytes_used() {
-  CountCSClosure cs_closure(this);
-  _g1->collection_set_iterate(&cs_closure);
-}
-
 void G1CollectorPolicy::print_tracing_info() const {
   _trace_gen0_time_data.print();
   _trace_gen1_time_data.print();
@@ -1696,7 +1676,7 @@ void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_l
   // retiring the current allocation region) or a concurrent
   // refine thread (RSet sampling).
 
-  double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
+  double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
   size_t used_bytes = hr->used();
   _inc_cset_recorded_rs_lengths += rs_length;
   _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
@@ -1731,7 +1711,7 @@ void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
   _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
 
   double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
-  double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
+  double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
   double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
   _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
 
@@ -1854,8 +1834,7 @@ bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
 }
 
 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
-  // Set this here - in case we're not doing young collections.
-  double non_young_start_time_sec = os::elapsedTime();
+  double young_start_time_sec = os::elapsedTime();
 
   YoungList* young_list = _g1->young_list();
   finalize_incremental_cset_building();
@@ -1869,17 +1848,14 @@ void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
   double predicted_pause_time_ms = base_time_ms;
   double time_remaining_ms = target_pause_time_ms - base_time_ms;
 
-  ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
+  ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
                 "start choosing CSet",
+                ergo_format_size("_pending_cards")
                 ergo_format_ms("predicted base time")
                 ergo_format_ms("remaining time")
                 ergo_format_ms("target pause time"),
-                base_time_ms, time_remaining_ms, target_pause_time_ms);
-
-  HeapRegion* hr;
-  double young_start_time_sec = os::elapsedTime();
+                _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
 
-  _collection_set_bytes_used_before = 0;
   _last_gc_was_young = gcs_are_young() ? true : false;
 
   if (_last_gc_was_young) {
@@ -1895,7 +1871,8 @@ void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
   uint survivor_region_length = young_list->survivor_length();
   uint eden_region_length = young_list->length() - survivor_region_length;
   init_cset_region_lengths(eden_region_length, survivor_region_length);
-  hr = young_list->first_survivor_region();
+
+  HeapRegion* hr = young_list->first_survivor_region();
   while (hr != NULL) {
     assert(hr->is_survivor(), "badly formed young list");
     hr->set_young();
@@ -1926,8 +1903,8 @@ void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
   phase_times()->_recorded_young_cset_choice_time_ms =
     (young_end_time_sec - young_start_time_sec) * 1000.0;
 
-  // We are doing young collections so reset this.
-  non_young_start_time_sec = young_end_time_sec;
+  // Set the start of the non-young choice time.
+  double non_young_start_time_sec = young_end_time_sec;
 
   if (!gcs_are_young()) {
     CollectionSetChooser* cset_chooser = _collectionSetChooser;
@@ -1937,6 +1914,7 @@ void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
 
     uint expensive_region_num = 0;
     bool check_time_remaining = adaptive_young_list_length();
+
     HeapRegion* hr = cset_chooser->peek();
     while (hr != NULL) {
       if (old_cset_region_length() >= max_old_cset_length) {
@@ -1950,7 +1928,7 @@ void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
         break;
       }
 
-      double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
+      double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
       if (check_time_remaining) {
         if (predicted_time_ms > time_remaining_ms) {
           // Too expensive for the current CSet.
@@ -2025,8 +2003,6 @@ void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
 
   stop_incremental_cset_building();
 
-  count_CS_bytes_used();
-
   ergo_verbose5(ErgoCSetConstruction,
                 "finish choosing CSet",
                 ergo_format_region("eden")

src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp

@@ -228,7 +228,6 @@ private:
   TruncatedSeq* _alloc_rate_ms_seq;
   double        _prev_collection_pause_end_ms;
 
-  TruncatedSeq* _pending_card_diff_seq;
   TruncatedSeq* _rs_length_diff_seq;
   TruncatedSeq* _cost_per_card_ms_seq;
   TruncatedSeq* _young_cards_per_entry_ratio_seq;
@@ -295,7 +294,6 @@ private:
   double _pause_time_target_ms;
 
   size_t _pending_cards;
-  size_t _max_pending_cards;
 
 public:
   // Accessors
@@ -325,28 +323,6 @@ public:
     _max_rs_lengths = rs_lengths;
   }
 
-  size_t predict_pending_card_diff() {
-    double prediction = get_new_neg_prediction(_pending_card_diff_seq);
-    if (prediction < 0.00001) {
-      return 0;
-    } else {
-      return (size_t) prediction;
-    }
-  }
-
-  size_t predict_pending_cards() {
-    size_t max_pending_card_num = _g1->max_pending_card_num();
-    size_t diff = predict_pending_card_diff();
-    size_t prediction;
-    if (diff > max_pending_card_num) {
-      prediction = max_pending_card_num;
-    } else {
-      prediction = max_pending_card_num - diff;
-    }
-
-    return prediction;
-  }
-
   size_t predict_rs_length_diff() {
     return (size_t) get_new_prediction(_rs_length_diff_seq);
   }
@@ -439,7 +415,7 @@ public:
   double predict_base_elapsed_time_ms(size_t pending_cards,
                                       size_t scanned_cards);
   size_t predict_bytes_to_copy(HeapRegion* hr);
-  double predict_region_elapsed_time_ms(HeapRegion* hr, bool young);
+  double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc);
 
   void set_recorded_rs_lengths(size_t rs_lengths);
 
@@ -495,12 +471,6 @@ public:
   }
 
 private:
-  size_t _bytes_in_collection_set_before_gc;
-  size_t _bytes_copied_during_gc;
-
-  // Used to count used bytes in CS.
-  friend class CountCSClosure;
-
   // Statistics kept per GC stoppage, pause or full.
   TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
 
@@ -514,9 +484,13 @@ private:
 
   // The number of bytes in the collection set before the pause. Set from
   // the incrementally built collection set at the start of an evacuation
-  // pause.
+  // pause, and incremented in finalize_cset() when adding old regions
+  // (if any) to the collection set.
   size_t _collection_set_bytes_used_before;
 
+  // The number of bytes copied during the GC.
+  size_t _bytes_copied_during_gc;
+
   // The associated information that is maintained while the incremental
   // collection set is being built with young regions. Used to populate
   // the recorded info for the evacuation pause.
@@ -646,9 +620,6 @@ private:
   bool predict_will_fit(uint young_length, double base_time_ms,
                         uint base_free_regions, double target_pause_time_ms);
 
-  // Count the number of bytes used in the CS.
-  void count_CS_bytes_used();
-
 public:
 
   G1CollectorPolicy();
@@ -666,10 +637,6 @@ public:
   // higher, recalculate the young list target length prediction.
   void revise_young_list_target_length_if_necessary();
 
-  size_t bytes_in_collection_set() {
-    return _bytes_in_collection_set_before_gc;
-  }
-
   // This should be called after the heap is resized.
   void record_new_heap_size(uint new_number_of_regions);
 

src/share/vm/gc_implementation/g1/g1ErgoVerbose.hpp

@@ -125,6 +125,7 @@ public:
 #define ergo_format_double(_name_)   ", " _name_ ": %1.2f"
 #define ergo_format_perc(_name_)     ", " _name_ ": %1.2f %%"
 #define ergo_format_ms(_name_)       ", " _name_ ": %1.2f ms"
+#define ergo_format_size(_name_)     ", " _name_ ": "SIZE_FORMAT
 
 // Double parameter format strings
 #define ergo_format_byte_perc(_name_)                                   \

src/share/vm/gc_implementation/g1/g1_globals.hpp

@@ -287,17 +287,17 @@
           "The number of times we'll force an overflow during "             \
           "concurrent marking")                                             \
                                                                             \
-  develop(uintx, G1DefaultMinNewGenPercent, 20,                             \
+  experimental(uintx, G1DefaultMinNewGenPercent, 20,                        \
           "Percentage (0-100) of the heap size to use as minimum "          \
           "young gen size.")                                                \
                                                                             \
-  develop(uintx, G1DefaultMaxNewGenPercent, 80,                             \
+  experimental(uintx, G1DefaultMaxNewGenPercent, 80,                        \
           "Percentage (0-100) of the heap size to use as maximum "          \
           "young gen size.")                                                \
                                                                             \
-  develop(uintx, G1OldCSetRegionLiveThresholdPercent, 90,                   \
+  experimental(uintx, G1OldCSetRegionLiveThresholdPercent, 90,              \
           "Threshold for regions to be added to the collection set. "       \
-          "Regions with more live bytes that this will not be collected.")  \
+          "Regions with more live bytes than this will not be collected.")  \
                                                                             \
   product(uintx, G1HeapWastePercent, 5,                                     \
           "Amount of space, expressed as a percentage of the heap size, "   \
@@ -306,7 +306,7 @@
   product(uintx, G1MixedGCCountTarget, 4,                                   \
           "The target number of mixed GCs after a marking cycle.")          \
                                                                             \
-  develop(uintx, G1OldCSetRegionThresholdPercent, 10,                       \
+  experimental(uintx, G1OldCSetRegionThresholdPercent, 10,                  \
           "An upper bound for the number of old CSet regions expressed "    \
           "as a percentage of the heap size.")                              \
                                                                             \

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

@@ -384,10 +384,17 @@ void HeapRegion::par_clear() {
 }
 
 void HeapRegion::calc_gc_efficiency() {
+  // GC efficiency is the ratio of how much space would be
+  // reclaimed over how long we predict it would take to reclaim it.
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   G1CollectorPolicy* g1p = g1h->g1_policy();
-  _gc_efficiency = (double) reclaimable_bytes() /
-                            g1p->predict_region_elapsed_time_ms(this, false);
+
+  // Retrieve a prediction of the elapsed time for this region for
+  // a mixed gc because the region will only be evacuated during a
+  // mixed gc.
+  double region_elapsed_time_ms =
+    g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
+  _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
 }
 
 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {