jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp@2ace1c4ee8da (annotated)

src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp@2ace1c4ee8da (annotated)

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

Tue, 10 Jan 2012 18:58:13 -0500

author: tonyp
date: Tue, 10 Jan 2012 18:58:13 -0500
changeset 3416: 2ace1c4ee8da
parent 3358: 1cbe7978b021
child 3456: 9509c20bba28
permissions: -rw-r--r--

6888336: G1: avoid explicitly marking and pushing objects in survivor spaces
Summary: This change simplifies the interaction between GC and concurrent marking. By disabling survivor spaces during the initial-mark pause we don't need to propagate marks of objects we copy during each GC (since we never need to copy an explicitly marked object).
Reviewed-by: johnc, brutisso

 /*
  * 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
  * 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 "gc_implementation/g1/concurrentG1Refine.hpp"
 #include "gc_implementation/g1/concurrentMark.hpp"
 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
 #include "gc_implementation/g1/g1ErgoVerbose.hpp"
 #include "gc_implementation/g1/heapRegionRemSet.hpp"
 #include "gc_implementation/shared/gcPolicyCounters.hpp"
 #include "runtime/arguments.hpp"
 #include "runtime/java.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "utilities/debug.hpp"
 // Different defaults for different number of GC threads
 // They were chosen by running GCOld and SPECjbb on debris with different
 //   numbers of GC threads and choosing them based on the results
 // all the same
 static double rs_length_diff_defaults[] = {
 .0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
 };
 static double cost_per_card_ms_defaults[] = {
 .01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
 };
 // all the same
 static double young_cards_per_entry_ratio_defaults[] = {
 .0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
 };
 static double cost_per_entry_ms_defaults[] = {
 .015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
 };
 static double cost_per_byte_ms_defaults[] = {
 .00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
 };
 // these should be pretty consistent
 static double constant_other_time_ms_defaults[] = {
 .0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
 };
 static double young_other_cost_per_region_ms_defaults[] = {
 .3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
 };
 static double non_young_other_cost_per_region_ms_defaults[] = {
 .0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
 };
 // Help class for avoiding interleaved logging
 class LineBuffer: public StackObj {
 private:
   static const int BUFFER_LEN = 1024;
   static const int INDENT_CHARS = 3;
   char _buffer[BUFFER_LEN];
   int _indent_level;
   int _cur;
   void vappend(const char* format, va_list ap) {
     int res = vsnprintf(&_buffer[_cur], BUFFER_LEN - _cur, format, ap);
     if (res != -1) {
       _cur += res;
     } else {
       DEBUG_ONLY(warning("buffer too small in LineBuffer");)
       _buffer[BUFFER_LEN -1] = 0;
       _cur = BUFFER_LEN; // vsnprintf above should not add to _buffer if we are called again
     }
   }
 public:
   explicit LineBuffer(int indent_level): _indent_level(indent_level), _cur(0) {
     for (; (_cur < BUFFER_LEN && _cur < (_indent_level * INDENT_CHARS)); _cur++) {
       _buffer[_cur] = ' ';
     }
   }
 #ifndef PRODUCT
   ~LineBuffer() {
     assert(_cur == _indent_level * INDENT_CHARS, "pending data in buffer - append_and_print_cr() not called?");
   }
 #endif
   void append(const char* format, ...) {
     va_list ap;
     va_start(ap, format);
     vappend(format, ap);
     va_end(ap);
   }
   void append_and_print_cr(const char* format, ...) {
     va_list ap;
     va_start(ap, format);
     vappend(format, ap);
     va_end(ap);
     gclog_or_tty->print_cr("%s", _buffer);
     _cur = _indent_level * INDENT_CHARS;
   }
 };
 G1CollectorPolicy::G1CollectorPolicy() :
   _parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads()
                         ? ParallelGCThreads : 1),
   _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   _all_pause_times_ms(new NumberSeq()),
   _stop_world_start(0.0),
   _all_stop_world_times_ms(new NumberSeq()),
   _all_yield_times_ms(new NumberSeq()),
   _summary(new Summary()),
   _cur_clear_ct_time_ms(0.0),
   _mark_closure_time_ms(0.0),
   _cur_ref_proc_time_ms(0.0),
   _cur_ref_enq_time_ms(0.0),
 #ifndef PRODUCT
   _min_clear_cc_time_ms(-1.0),
   _max_clear_cc_time_ms(-1.0),
   _cur_clear_cc_time_ms(0.0),
   _cum_clear_cc_time_ms(0.0),
   _num_cc_clears(0L),
 #endif
   _aux_num(10),
   _all_aux_times_ms(new NumberSeq[_aux_num]),
   _cur_aux_start_times_ms(new double[_aux_num]),
   _cur_aux_times_ms(new double[_aux_num]),
   _cur_aux_times_set(new bool[_aux_num]),
   _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   _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)),
   _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
   _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
   _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   _non_young_other_cost_per_region_ms_seq(
                                          new TruncatedSeq(TruncatedSeqLength)),
   _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
   _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
   _pause_time_target_ms((double) MaxGCPauseMillis),
   _gcs_are_young(true),
   _young_pause_num(0),
   _mixed_pause_num(0),
   _during_marking(false),
   _in_marking_window(false),
   _in_marking_window_im(false),
   _known_garbage_ratio(0.0),
   _known_garbage_bytes(0),
   _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
   _recent_prev_end_times_for_all_gcs_sec(
                                 new TruncatedSeq(NumPrevPausesForHeuristics)),
   _recent_avg_pause_time_ratio(0.0),
   _all_full_gc_times_ms(new NumberSeq()),
   _initiate_conc_mark_if_possible(false),
   _during_initial_mark_pause(false),
   _should_revert_to_young_gcs(false),
   _last_young_gc(false),
   _last_gc_was_young(false),
   _eden_bytes_before_gc(0),
   _survivor_bytes_before_gc(0),
   _capacity_before_gc(0),
   _prev_collection_pause_used_at_end_bytes(0),
   _eden_cset_region_length(0),
   _survivor_cset_region_length(0),
   _old_cset_region_length(0),
   _collection_set(NULL),
   _collection_set_bytes_used_before(0),
   // Incremental CSet attributes
   _inc_cset_build_state(Inactive),
   _inc_cset_head(NULL),
   _inc_cset_tail(NULL),
   _inc_cset_bytes_used_before(0),
   _inc_cset_max_finger(NULL),
   _inc_cset_recorded_rs_lengths(0),
   _inc_cset_recorded_rs_lengths_diffs(0),
   _inc_cset_predicted_elapsed_time_ms(0.0),
   _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
 #endif // _MSC_VER
   _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
                                                  G1YoungSurvRateNumRegionsSummary)),
   _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
                                               G1YoungSurvRateNumRegionsSummary)),
   // add here any more surv rate groups
   _recorded_survivor_regions(0),
   _recorded_survivor_head(NULL),
   _recorded_survivor_tail(NULL),
   _survivors_age_table(true),
   _gc_overhead_perc(0.0) {
   // Set up the region size and associated fields. Given that the
   // policy is created before the heap, we have to set this up here,
   // so it's done as soon as possible.
   HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
   HeapRegionRemSet::setup_remset_size();
   G1ErgoVerbose::initialize();
   if (PrintAdaptiveSizePolicy) {
     // Currently, we only use a single switch for all the heuristics.
     G1ErgoVerbose::set_enabled(true);
     // Given that we don't currently have a verboseness level
     // parameter, we'll hardcode this to high. This can be easily
     // changed in the future.
     G1ErgoVerbose::set_level(ErgoHigh);
   } else {
     G1ErgoVerbose::set_enabled(false);
   }
   // Verify PLAB sizes
   const size_t region_size = HeapRegion::GrainWords;
   if (YoungPLABSize > region_size || OldPLABSize > region_size) {
     char buffer[128];
     jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT,
                  OldPLABSize > region_size ? "Old" : "Young", region_size);
     vm_exit_during_initialization(buffer);
   }
   _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
   _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
   _par_last_gc_worker_start_times_ms = new double[_parallel_gc_threads];
   _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
   _par_last_satb_filtering_times_ms = new double[_parallel_gc_threads];
   _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
   _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
   _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
   _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
   _par_last_termination_times_ms = new double[_parallel_gc_threads];
   _par_last_termination_attempts = new double[_parallel_gc_threads];
   _par_last_gc_worker_end_times_ms = new double[_parallel_gc_threads];
   _par_last_gc_worker_times_ms = new double[_parallel_gc_threads];
   _par_last_gc_worker_other_times_ms = new double[_parallel_gc_threads];
   // start conservatively
   _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
   int index;
   if (ParallelGCThreads == 0)
     index = 0;
   else if (ParallelGCThreads > 8)
     index = 7;
   else
     index = ParallelGCThreads - 1;
   _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(
                                   young_cards_per_entry_ratio_defaults[index]);
   _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
   _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
   _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
   _young_other_cost_per_region_ms_seq->add(
                                young_other_cost_per_region_ms_defaults[index]);
   _non_young_other_cost_per_region_ms_seq->add(
                            non_young_other_cost_per_region_ms_defaults[index]);
   // Below, we might need to calculate the pause time target based on
   // the pause interval. When we do so we are going to give G1 maximum
   // flexibility and allow it to do pauses when it needs to. So, we'll
   // arrange that the pause interval to be pause time target + 1 to
   // ensure that a) the pause time target is maximized with respect to
   // the pause interval and b) we maintain the invariant that pause
   // time target < pause interval. If the user does not want this
   // maximum flexibility, they will have to set the pause interval
   // explicitly.
   // First make sure that, if either parameter is set, its value is
   // reasonable.
   if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
     if (MaxGCPauseMillis < 1) {
       vm_exit_during_initialization("MaxGCPauseMillis should be "
                                     "greater than 0");
     }
   }
   if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
     if (GCPauseIntervalMillis < 1) {
       vm_exit_during_initialization("GCPauseIntervalMillis should be "
                                     "greater than 0");
     }
   }
   // Then, if the pause time target parameter was not set, set it to
   // the default value.
   if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
     if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
       // The default pause time target in G1 is 200ms
       FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
     } else {
       // We do not allow the pause interval to be set without the
       // pause time target
       vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
                                     "without setting MaxGCPauseMillis");
     }
   }
   // Then, if the interval parameter was not set, set it according to
   // the pause time target (this will also deal with the case when the
   // pause time target is the default value).
   if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
     FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
   }
   // Finally, make sure that the two parameters are consistent.
   if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
     char buffer[256];
     jio_snprintf(buffer, 256,
                  "MaxGCPauseMillis (%u) should be less than "
                  "GCPauseIntervalMillis (%u)",
                  MaxGCPauseMillis, GCPauseIntervalMillis);
     vm_exit_during_initialization(buffer);
   }
   double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
   double time_slice  = (double) GCPauseIntervalMillis / 1000.0;
   _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
   _sigma = (double) G1ConfidencePercent / 100.0;
   // start conservatively (around 50ms is about right)
   _concurrent_mark_remark_times_ms->add(0.05);
   _concurrent_mark_cleanup_times_ms->add(0.20);
   _tenuring_threshold = MaxTenuringThreshold;
   // _max_survivor_regions will be calculated by
   // update_young_list_target_length() during initialization.
   _max_survivor_regions = 0;
   assert(GCTimeRatio > 0,
          "we should have set it to a default value set_g1_gc_flags() "
          "if a user set it to 0");
   _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
   uintx reserve_perc = G1ReservePercent;
   // Put an artificial ceiling on this so that it's not set to a silly value.
   if (reserve_perc > 50) {
     reserve_perc = 50;
     warning("G1ReservePercent is set to a value that is too large, "
             "it's been updated to %u", reserve_perc);
   }
   _reserve_factor = (double) reserve_perc / 100.0;
   // This will be set when the heap is expanded
   // for the first time during initialization.
   _reserve_regions = 0;
   initialize_all();
   _collectionSetChooser = new CollectionSetChooser();
   _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
 }
 void G1CollectorPolicy::initialize_flags() {
   set_min_alignment(HeapRegion::GrainBytes);
   set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
   if (SurvivorRatio < 1) {
     vm_exit_during_initialization("Invalid survivor ratio specified");
   }
   CollectorPolicy::initialize_flags();
 }
 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true) {
   assert(G1DefaultMinNewGenPercent <= G1DefaultMaxNewGenPercent, "Min larger than max");
   assert(G1DefaultMinNewGenPercent > 0 && G1DefaultMinNewGenPercent < 100, "Min out of bounds");
   assert(G1DefaultMaxNewGenPercent > 0 && G1DefaultMaxNewGenPercent < 100, "Max out of bounds");
   if (FLAG_IS_CMDLINE(NewRatio)) {
     if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
       warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
     } else {
       _sizer_kind = SizerNewRatio;
       _adaptive_size = false;
       return;
     }
   }
   if (FLAG_IS_CMDLINE(NewSize)) {
      _min_desired_young_length = MAX2((size_t) 1, NewSize / HeapRegion::GrainBytes);
     if (FLAG_IS_CMDLINE(MaxNewSize)) {
       _max_desired_young_length = MAX2((size_t) 1, MaxNewSize / HeapRegion::GrainBytes);
       _sizer_kind = SizerMaxAndNewSize;
       _adaptive_size = _min_desired_young_length == _max_desired_young_length;
     } else {
       _sizer_kind = SizerNewSizeOnly;
     }
   } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
     _max_desired_young_length = MAX2((size_t) 1, MaxNewSize / HeapRegion::GrainBytes);
     _sizer_kind = SizerMaxNewSizeOnly;
   }
 }
 size_t G1YoungGenSizer::calculate_default_min_length(size_t new_number_of_heap_regions) {
   size_t default_value = (new_number_of_heap_regions * G1DefaultMinNewGenPercent) / 100;
   return MAX2((size_t)1, default_value);
 }
 size_t G1YoungGenSizer::calculate_default_max_length(size_t new_number_of_heap_regions) {
   size_t default_value = (new_number_of_heap_regions * G1DefaultMaxNewGenPercent) / 100;
   return MAX2((size_t)1, default_value);
 }
 void G1YoungGenSizer::heap_size_changed(size_t new_number_of_heap_regions) {
   assert(new_number_of_heap_regions > 0, "Heap must be initialized");
   switch (_sizer_kind) {
     case SizerDefaults:
       _min_desired_young_length = calculate_default_min_length(new_number_of_heap_regions);
       _max_desired_young_length = calculate_default_max_length(new_number_of_heap_regions);
       break;
     case SizerNewSizeOnly:
       _max_desired_young_length = calculate_default_max_length(new_number_of_heap_regions);
       _max_desired_young_length = MAX2(_min_desired_young_length, _max_desired_young_length);
       break;
     case SizerMaxNewSizeOnly:
       _min_desired_young_length = calculate_default_min_length(new_number_of_heap_regions);
       _min_desired_young_length = MIN2(_min_desired_young_length, _max_desired_young_length);
       break;
     case SizerMaxAndNewSize:
       // Do nothing. Values set on the command line, don't update them at runtime.
       break;
     case SizerNewRatio:
       _min_desired_young_length = new_number_of_heap_regions / (NewRatio + 1);
       _max_desired_young_length = _min_desired_young_length;
       break;
     default:
       ShouldNotReachHere();
   }
   assert(_min_desired_young_length <= _max_desired_young_length, "Invalid min/max young gen size values");
 }
 void G1CollectorPolicy::init() {
   // Set aside an initial future to_space.
   _g1 = G1CollectedHeap::heap();
   assert(Heap_lock->owned_by_self(), "Locking discipline.");
   initialize_gc_policy_counters();
   if (adaptive_young_list_length()) {
     _young_list_fixed_length = 0;
   } else {
     _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
   }
   _free_regions_at_end_of_collection = _g1->free_regions();
   update_young_list_target_length();
   _prev_eden_capacity = _young_list_target_length * HeapRegion::GrainBytes;
   // We may immediately start allocating regions and placing them on the
   // collection set list. Initialize the per-collection set info
   start_incremental_cset_building();
 }
 // Create the jstat counters for the policy.
 void G1CollectorPolicy::initialize_gc_policy_counters() {
   _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
 }
 bool G1CollectorPolicy::predict_will_fit(size_t young_length,
                                          double base_time_ms,
                                          size_t base_free_regions,
                                          double target_pause_time_ms) {
   if (young_length >= base_free_regions) {
     // end condition 1: not enough space for the young regions
     return false;
   }
   double accum_surv_rate = accum_yg_surv_rate_pred((int)(young_length - 1));
   size_t bytes_to_copy =
                (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
   double young_other_time_ms = predict_young_other_time_ms(young_length);
   double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
   if (pause_time_ms > target_pause_time_ms) {
     // end condition 2: prediction is over the target pause time
     return false;
   }
   size_t free_bytes =
                   (base_free_regions - young_length) * HeapRegion::GrainBytes;
   if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
     // end condition 3: out-of-space (conservatively!)
     return false;
   }
   // success!
   return true;
 }
 void G1CollectorPolicy::record_new_heap_size(size_t new_number_of_regions) {
   // re-calculate the necessary reserve
   double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
   // We use ceiling so that if reserve_regions_d is > 0.0 (but
   // smaller than 1.0) we'll get 1.
   _reserve_regions = (size_t) ceil(reserve_regions_d);
   _young_gen_sizer->heap_size_changed(new_number_of_regions);
 }
 size_t G1CollectorPolicy::calculate_young_list_desired_min_length(
                                                      size_t base_min_length) {
   size_t desired_min_length = 0;
   if (adaptive_young_list_length()) {
     if (_alloc_rate_ms_seq->num() > 3) {
       double now_sec = os::elapsedTime();
       double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
       double alloc_rate_ms = predict_alloc_rate_ms();
       desired_min_length = (size_t) ceil(alloc_rate_ms * when_ms);
     } else {
       // otherwise we don't have enough info to make the prediction
     }
   }
   desired_min_length += base_min_length;
   // make sure we don't go below any user-defined minimum bound
   return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
 }
 size_t G1CollectorPolicy::calculate_young_list_desired_max_length() {
   // Here, we might want to also take into account any additional
   // constraints (i.e., user-defined minimum bound). Currently, we
   // effectively don't set this bound.
   return _young_gen_sizer->max_desired_young_length();
 }
 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
   if (rs_lengths == (size_t) -1) {
     // if it's set to the default value (-1), we should predict it;
     // otherwise, use the given value.
     rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
   }
   // Calculate the absolute and desired min bounds.
   // This is how many young regions we already have (currently: the survivors).
   size_t base_min_length = recorded_survivor_regions();
   // This is the absolute minimum young length, which ensures that we
   // can allocate one eden region in the worst-case.
   size_t absolute_min_length = base_min_length + 1;
   size_t desired_min_length =
                      calculate_young_list_desired_min_length(base_min_length);
   if (desired_min_length < absolute_min_length) {
     desired_min_length = absolute_min_length;
   }
   // Calculate the absolute and desired max bounds.
   // We will try our best not to "eat" into the reserve.
   size_t absolute_max_length = 0;
   if (_free_regions_at_end_of_collection > _reserve_regions) {
     absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
   }
   size_t desired_max_length = calculate_young_list_desired_max_length();
   if (desired_max_length > absolute_max_length) {
     desired_max_length = absolute_max_length;
   }
   size_t young_list_target_length = 0;
   if (adaptive_young_list_length()) {
     if (gcs_are_young()) {
       young_list_target_length =
                         calculate_young_list_target_length(rs_lengths,
                                                            base_min_length,
                                                            desired_min_length,
                                                            desired_max_length);
       _rs_lengths_prediction = rs_lengths;
     } else {
       // Don't calculate anything and let the code below bound it to
       // the desired_min_length, i.e., do the next GC as soon as
       // possible to maximize how many old regions we can add to it.
     }
   } else {
     if (gcs_are_young()) {
       young_list_target_length = _young_list_fixed_length;
     } else {
       // A bit arbitrary: during mixed GCs we allocate half
       // the young regions to try to add old regions to the CSet.
       young_list_target_length = _young_list_fixed_length / 2;
       // We choose to accept that we might go under the desired min
       // length given that we intentionally ask for a smaller young gen.
       desired_min_length = absolute_min_length;
     }
   }
   // Make sure we don't go over the desired max length, nor under the
   // desired min length. In case they clash, desired_min_length wins
   // which is why that test is second.
   if (young_list_target_length > desired_max_length) {
     young_list_target_length = desired_max_length;
   }
   if (young_list_target_length < desired_min_length) {
     young_list_target_length = desired_min_length;
   }
   assert(young_list_target_length > recorded_survivor_regions(),
          "we should be able to allocate at least one eden region");
   assert(young_list_target_length >= absolute_min_length, "post-condition");
   _young_list_target_length = young_list_target_length;
   update_max_gc_locker_expansion();
 }
 size_t
 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
                                                    size_t base_min_length,
                                                    size_t desired_min_length,
                                                    size_t desired_max_length) {
   assert(adaptive_young_list_length(), "pre-condition");
   assert(gcs_are_young(), "only call this for young GCs");
   // In case some edge-condition makes the desired max length too small...
   if (desired_max_length <= desired_min_length) {
     return desired_min_length;
   }
   // We'll adjust min_young_length and max_young_length not to include
   // the already allocated young regions (i.e., so they reflect the
   // min and max eden regions we'll allocate). The base_min_length
   // will be reflected in the predictions by the
   // survivor_regions_evac_time prediction.
   assert(desired_min_length > base_min_length, "invariant");
   size_t min_young_length = desired_min_length - base_min_length;
   assert(desired_max_length > base_min_length, "invariant");
   size_t max_young_length = desired_max_length - base_min_length;
   double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
   double survivor_regions_evac_time = predict_survivor_regions_evac_time();
   size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
   size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
   size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
   double base_time_ms =
     predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
     survivor_regions_evac_time;
   size_t available_free_regions = _free_regions_at_end_of_collection;
   size_t base_free_regions = 0;
   if (available_free_regions > _reserve_regions) {
     base_free_regions = available_free_regions - _reserve_regions;
   }
   // Here, we will make sure that the shortest young length that
   // makes sense fits within the target pause time.
   if (predict_will_fit(min_young_length, base_time_ms,
                        base_free_regions, target_pause_time_ms)) {
     // The shortest young length will fit into the target pause time;
     // we'll now check whether the absolute maximum number of young
     // regions will fit in the target pause time. If not, we'll do
     // a binary search between min_young_length and max_young_length.
     if (predict_will_fit(max_young_length, base_time_ms,
                          base_free_regions, target_pause_time_ms)) {
       // The maximum young length will fit into the target pause time.
       // We are done so set min young length to the maximum length (as
       // the result is assumed to be returned in min_young_length).
       min_young_length = max_young_length;
     } else {
       // The maximum possible number of young regions will not fit within
       // the target pause time so we'll search for the optimal
       // length. The loop invariants are:
       //
       // min_young_length < max_young_length
       // min_young_length is known to fit into the target pause time
       // max_young_length is known not to fit into the target pause time
       //
       // Going into the loop we know the above hold as we've just
       // checked them. Every time around the loop we check whether
       // the middle value between min_young_length and
       // max_young_length fits into the target pause time. If it
       // does, it becomes the new min. If it doesn't, it becomes
       // the new max. This way we maintain the loop invariants.
       assert(min_young_length < max_young_length, "invariant");
       size_t diff = (max_young_length - min_young_length) / 2;
       while (diff > 0) {
         size_t young_length = min_young_length + diff;
         if (predict_will_fit(young_length, base_time_ms,
                              base_free_regions, target_pause_time_ms)) {
           min_young_length = young_length;
         } else {
           max_young_length = young_length;
         }
         assert(min_young_length <  max_young_length, "invariant");
         diff = (max_young_length - min_young_length) / 2;
       }
       // The results is min_young_length which, according to the
       // loop invariants, should fit within the target pause time.
       // These are the post-conditions of the binary search above:
       assert(min_young_length < max_young_length,
              "otherwise we should have discovered that max_young_length "
              "fits into the pause target and not done the binary search");
       assert(predict_will_fit(min_young_length, base_time_ms,
                               base_free_regions, target_pause_time_ms),
              "min_young_length, the result of the binary search, should "
              "fit into the pause target");
       assert(!predict_will_fit(min_young_length + 1, base_time_ms,
                                base_free_regions, target_pause_time_ms),
              "min_young_length, the result of the binary search, should be "
              "optimal, so no larger length should fit into the pause target");
     }
   } else {
     // Even the minimum length doesn't fit into the pause time
     // target, return it as the result nevertheless.
   }
   return base_min_length + min_young_length;
 }
 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
   double survivor_regions_evac_time = 0.0;
   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);
   }
   return survivor_regions_evac_time;
 }
 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
   size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
   if (rs_lengths > _rs_lengths_prediction) {
     // add 10% to avoid having to recalculate often
     size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
     update_young_list_target_length(rs_lengths_prediction);
   }
 }
 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
                                                bool is_tlab,
                                                bool* gc_overhead_limit_was_exceeded) {
   guarantee(false, "Not using this policy feature yet.");
   return NULL;
 }
 // This method controls how a collector handles one or more
 // of its generations being fully allocated.
 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
                                                        bool is_tlab) {
   guarantee(false, "Not using this policy feature yet.");
   return NULL;
 }
 #ifndef PRODUCT
 bool G1CollectorPolicy::verify_young_ages() {
   HeapRegion* head = _g1->young_list()->first_region();
   return
     verify_young_ages(head, _short_lived_surv_rate_group);
   // also call verify_young_ages on any additional surv rate groups
 }
 bool
 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
                                      SurvRateGroup *surv_rate_group) {
   guarantee( surv_rate_group != NULL, "pre-condition" );
   const char* name = surv_rate_group->name();
   bool ret = true;
   int prev_age = -1;
   for (HeapRegion* curr = head;
        curr != NULL;
        curr = curr->get_next_young_region()) {
     SurvRateGroup* group = curr->surv_rate_group();
     if (group == NULL && !curr->is_survivor()) {
       gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
       ret = false;
     }
     if (surv_rate_group == group) {
       int age = curr->age_in_surv_rate_group();
       if (age < 0) {
         gclog_or_tty->print_cr("## %s: encountered negative age", name);
         ret = false;
       }
       if (age <= prev_age) {
         gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
                                "(%d, %d)", name, age, prev_age);
         ret = false;
       }
       prev_age = age;
     }
   }
   return ret;
 }
 #endif // PRODUCT
 void G1CollectorPolicy::record_full_collection_start() {
   _cur_collection_start_sec = os::elapsedTime();
   // Release the future to-space so that it is available for compaction into.
   _g1->set_full_collection();
 }
 void G1CollectorPolicy::record_full_collection_end() {
   // Consider this like a collection pause for the purposes of allocation
   // since last pause.
   double end_sec = os::elapsedTime();
   double full_gc_time_sec = end_sec - _cur_collection_start_sec;
   double full_gc_time_ms = full_gc_time_sec * 1000.0;
   _all_full_gc_times_ms->add(full_gc_time_ms);
   update_recent_gc_times(end_sec, full_gc_time_ms);
   _g1->clear_full_collection();
   // "Nuke" the heuristics that control the young/mixed GC
   // transitions and make sure we start with young GCs after the Full GC.
   set_gcs_are_young(true);
   _last_young_gc = false;
   _should_revert_to_young_gcs = false;
   clear_initiate_conc_mark_if_possible();
   clear_during_initial_mark_pause();
   _known_garbage_bytes = 0;
   _known_garbage_ratio = 0.0;
   _in_marking_window = false;
   _in_marking_window_im = false;
   _short_lived_surv_rate_group->start_adding_regions();
   // also call this on any additional surv rate groups
   record_survivor_regions(0, NULL, NULL);
   _free_regions_at_end_of_collection = _g1->free_regions();
   // Reset survivors SurvRateGroup.
   _survivor_surv_rate_group->reset();
   update_young_list_target_length();
   _collectionSetChooser->updateAfterFullCollection();
 }
 void G1CollectorPolicy::record_stop_world_start() {
   _stop_world_start = os::elapsedTime();
 }
 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
                                                       size_t start_used) {
   if (PrintGCDetails) {
     gclog_or_tty->stamp(PrintGCTimeStamps);
     gclog_or_tty->print("[GC pause");
     gclog_or_tty->print(" (%s)", gcs_are_young() ? "young" : "mixed");
   }
   if (!during_initial_mark_pause()) {
     // We only need to do this here as the policy will only be applied
     // to the GC we're about to start. so, no point is calculating this
     // every time we calculate / recalculate the target young length.
     update_survivors_policy();
   } else {
     // The marking phase has a "we only copy implicitly live
     // objects during marking" invariant. The easiest way to ensure it
     // holds is not to allocate any survivor regions and tenure all
     // objects. In the future we might change this and handle survivor
     // regions specially during marking.
     tenure_all_objects();
   }
   assert(_g1->used() == _g1->recalculate_used(),
          err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
                  _g1->used(), _g1->recalculate_used()));
   double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
   _all_stop_world_times_ms->add(s_w_t_ms);
   _stop_world_start = 0.0;
   _cur_collection_start_sec = 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;
   _bytes_copied_during_gc = 0;
   YoungList* young_list = _g1->young_list();
   _eden_bytes_before_gc = young_list->eden_used_bytes();
   _survivor_bytes_before_gc = young_list->survivor_used_bytes();
   _capacity_before_gc = _g1->capacity();
 #ifdef DEBUG
   // initialise these to something well known so that we can spot
   // if they are not set properly
   for (int i = 0; i < _parallel_gc_threads; ++i) {
     _par_last_gc_worker_start_times_ms[i] = -1234.0;
     _par_last_ext_root_scan_times_ms[i] = -1234.0;
     _par_last_satb_filtering_times_ms[i] = -1234.0;
     _par_last_update_rs_times_ms[i] = -1234.0;
     _par_last_update_rs_processed_buffers[i] = -1234.0;
     _par_last_scan_rs_times_ms[i] = -1234.0;
     _par_last_obj_copy_times_ms[i] = -1234.0;
     _par_last_termination_times_ms[i] = -1234.0;
     _par_last_termination_attempts[i] = -1234.0;
     _par_last_gc_worker_end_times_ms[i] = -1234.0;
     _par_last_gc_worker_times_ms[i] = -1234.0;
     _par_last_gc_worker_other_times_ms[i] = -1234.0;
   }
 #endif
   for (int i = 0; i < _aux_num; ++i) {
     _cur_aux_times_ms[i] = 0.0;
     _cur_aux_times_set[i] = false;
   }
   // This is initialized to zero here and is set during
   // the evacuation pause if marking is in progress.
   _cur_satb_drain_time_ms = 0.0;
   _last_gc_was_young = false;
   // do that for any other surv rate groups
   _short_lived_surv_rate_group->stop_adding_regions();
   _survivors_age_table.clear();
   assert( verify_young_ages(), "region age verification" );
 }
 void G1CollectorPolicy::record_concurrent_mark_init_end(double
                                                    mark_init_elapsed_time_ms) {
   _during_marking = true;
   assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
   clear_during_initial_mark_pause();
   _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
 }
 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
   _mark_remark_start_sec = os::elapsedTime();
   _during_marking = false;
 }
 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
   double end_time_sec = os::elapsedTime();
   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
   _cur_mark_stop_world_time_ms += elapsed_time_ms;
   _prev_collection_pause_end_ms += elapsed_time_ms;
   _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
 }
 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
   _mark_cleanup_start_sec = os::elapsedTime();
 }
 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
   _should_revert_to_young_gcs = false;
   _last_young_gc = true;
   _in_marking_window = false;
 }
 void G1CollectorPolicy::record_concurrent_pause() {
   if (_stop_world_start > 0.0) {
     double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
     _all_yield_times_ms->add(yield_ms);
   }
 }
 void G1CollectorPolicy::record_concurrent_pause_end() {
 }
 template<class T>
 T sum_of(T* sum_arr, int start, int n, int N) {
   T sum = (T)0;
   for (int i = 0; i < n; i++) {
     int j = (start + i) % N;
     sum += sum_arr[j];
   }
   return sum;
 }
 void G1CollectorPolicy::print_par_stats(int level,
                                         const char* str,
                                         double* data) {
   double min = data[0], max = data[0];
   double total = 0.0;
   LineBuffer buf(level);
   buf.append("[%s (ms):", str);
   for (uint i = 0; i < no_of_gc_threads(); ++i) {
     double val = data[i];
     if (val < min)
       min = val;
     if (val > max)
       max = val;
     total += val;
     buf.append("  %3.1lf", val);
   }
   buf.append_and_print_cr("");
   double avg = total / (double) no_of_gc_threads();
   buf.append_and_print_cr(" Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf, Diff: %5.1lf]",
     avg, min, max, max - min);
 }
 void G1CollectorPolicy::print_par_sizes(int level,
                                         const char* str,
                                         double* data) {
   double min = data[0], max = data[0];
   double total = 0.0;
   LineBuffer buf(level);
   buf.append("[%s :", str);
   for (uint i = 0; i < no_of_gc_threads(); ++i) {
     double val = data[i];
     if (val < min)
       min = val;
     if (val > max)
       max = val;
     total += val;
     buf.append(" %d", (int) val);
   }
   buf.append_and_print_cr("");
   double avg = total / (double) no_of_gc_threads();
   buf.append_and_print_cr(" Sum: %d, Avg: %d, Min: %d, Max: %d, Diff: %d]",
     (int)total, (int)avg, (int)min, (int)max, (int)max - (int)min);
 }
 void G1CollectorPolicy::print_stats(int level,
                                     const char* str,
                                     double value) {
   LineBuffer(level).append_and_print_cr("[%s: %5.1lf ms]", str, value);
 }
 void G1CollectorPolicy::print_stats(int level,
                                     const char* str,
                                     int value) {
   LineBuffer(level).append_and_print_cr("[%s: %d]", str, value);
 }
 double G1CollectorPolicy::avg_value(double* data) {
   if (G1CollectedHeap::use_parallel_gc_threads()) {
     double ret = 0.0;
     for (uint i = 0; i < no_of_gc_threads(); ++i) {
       ret += data[i];
     }
     return ret / (double) no_of_gc_threads();
   } else {
     return data[0];
   }
 }
 double G1CollectorPolicy::max_value(double* data) {
   if (G1CollectedHeap::use_parallel_gc_threads()) {
     double ret = data[0];
     for (uint i = 1; i < no_of_gc_threads(); ++i) {
       if (data[i] > ret) {
         ret = data[i];
       }
     }
     return ret;
   } else {
     return data[0];
   }
 }
 double G1CollectorPolicy::sum_of_values(double* data) {
   if (G1CollectedHeap::use_parallel_gc_threads()) {
     double sum = 0.0;
     for (uint i = 0; i < no_of_gc_threads(); i++) {
       sum += data[i];
     }
     return sum;
   } else {
     return data[0];
   }
 }
 double G1CollectorPolicy::max_sum(double* data1, double* data2) {
   double ret = data1[0] + data2[0];
   if (G1CollectedHeap::use_parallel_gc_threads()) {
     for (uint i = 1; i < no_of_gc_threads(); ++i) {
       double data = data1[i] + data2[i];
       if (data > ret) {
         ret = data;
       }
     }
   }
   return ret;
 }
 // Anything below that is considered to be zero
 #define MIN_TIMER_GRANULARITY 0.0000001
 void G1CollectorPolicy::record_collection_pause_end(int no_of_gc_threads) {
   double end_time_sec = os::elapsedTime();
   double elapsed_ms = _last_pause_time_ms;
   bool parallel = G1CollectedHeap::use_parallel_gc_threads();
   assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
          "otherwise, the subtraction below does not make sense");
   size_t rs_size =
             _cur_collection_pause_used_regions_at_start - cset_region_length();
   size_t cur_used_bytes = _g1->used();
   assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
   bool last_pause_included_initial_mark = false;
   bool update_stats = !_g1->evacuation_failed();
   set_no_of_gc_threads(no_of_gc_threads);
 #ifndef PRODUCT
   if (G1YoungSurvRateVerbose) {
     gclog_or_tty->print_cr("");
     _short_lived_surv_rate_group->print();
     // do that for any other surv rate groups too
   }
 #endif // PRODUCT
   last_pause_included_initial_mark = during_initial_mark_pause();
   if (last_pause_included_initial_mark)
     record_concurrent_mark_init_end(0.0);
   size_t marking_initiating_used_threshold =
     (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
   if (!_g1->mark_in_progress() && !_last_young_gc) {
     assert(!last_pause_included_initial_mark, "invariant");
     if (cur_used_bytes > marking_initiating_used_threshold) {
       if (cur_used_bytes > _prev_collection_pause_used_at_end_bytes) {
         assert(!during_initial_mark_pause(), "we should not see this here");
         ergo_verbose3(ErgoConcCycles,
                       "request concurrent cycle initiation",
                       ergo_format_reason("occupancy higher than threshold")
                       ergo_format_byte("occupancy")
                       ergo_format_byte_perc("threshold"),
                       cur_used_bytes,
                       marking_initiating_used_threshold,
                       (double) InitiatingHeapOccupancyPercent);
         // Note: this might have already been set, if during the last
         // pause we decided to start a cycle but at the beginning of
         // this pause we decided to postpone it. That's OK.
         set_initiate_conc_mark_if_possible();
       } else {
         ergo_verbose2(ErgoConcCycles,
                   "do not request concurrent cycle initiation",
                   ergo_format_reason("occupancy lower than previous occupancy")
                   ergo_format_byte("occupancy")
                   ergo_format_byte("previous occupancy"),
                   cur_used_bytes,
                   _prev_collection_pause_used_at_end_bytes);
       }
     }
   }
   _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
   _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
                           end_time_sec, false);
   // This assert is exempted when we're doing parallel collection pauses,
   // because the fragmentation caused by the parallel GC allocation buffers
   // can lead to more memory being used during collection than was used
   // before. Best leave this out until the fragmentation problem is fixed.
   // Pauses in which evacuation failed can also lead to negative
   // collections, since no space is reclaimed from a region containing an
   // object whose evacuation failed.
   // Further, we're now always doing parallel collection.  But I'm still
   // leaving this here as a placeholder for a more precise assertion later.
   // (DLD, 10/05.)
   assert((true || parallel) // Always using GC LABs now.
          || _g1->evacuation_failed()
          || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
          "Negative collection");
   size_t freed_bytes =
     _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
   size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
   double survival_fraction =
     (double)surviving_bytes/
     (double)_collection_set_bytes_used_before;
   // These values are used to update the summary information that is
   // displayed when TraceGen0Time is enabled, and are output as part
   // of the PrintGCDetails output, in the non-parallel case.
   double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
   double satb_filtering_time = avg_value(_par_last_satb_filtering_times_ms);
   double update_rs_time = avg_value(_par_last_update_rs_times_ms);
   double update_rs_processed_buffers =
     sum_of_values(_par_last_update_rs_processed_buffers);
   double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
   double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
   double termination_time = avg_value(_par_last_termination_times_ms);
   double known_time = ext_root_scan_time +
                       satb_filtering_time +
                       update_rs_time +
                       scan_rs_time +
                       obj_copy_time;
   double other_time_ms = elapsed_ms;
   // Subtract the SATB drain time. It's initialized to zero at the
   // start of the pause and is updated during the pause if marking
   // is in progress.
   other_time_ms -= _cur_satb_drain_time_ms;
   if (parallel) {
     other_time_ms -= _cur_collection_par_time_ms;
   } else {
     other_time_ms -= known_time;
   }
   // Subtract the time taken to clean the card table from the
   // current value of "other time"
   other_time_ms -= _cur_clear_ct_time_ms;
   // Subtract the time spent completing marking in the collection
   // set. Note if marking is not in progress during the pause
   // the value of _mark_closure_time_ms will be zero.
   other_time_ms -= _mark_closure_time_ms;
   // TraceGen0Time and TraceGen1Time summary info updating.
   _all_pause_times_ms->add(elapsed_ms);
   if (update_stats) {
     _summary->record_total_time_ms(elapsed_ms);
     _summary->record_other_time_ms(other_time_ms);
     MainBodySummary* body_summary = _summary->main_body_summary();
     assert(body_summary != NULL, "should not be null!");
     // This will be non-zero iff marking is currently in progress (i.e.
     // _g1->mark_in_progress() == true) and the currrent pause was not
     // an initial mark pause. Since the body_summary items are NumberSeqs,
     // however, they have to be consistent and updated in lock-step with
     // each other. Therefore we unconditionally record the SATB drain
     // time - even if it's zero.
     body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
     body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
     body_summary->record_satb_filtering_time_ms(satb_filtering_time);
     body_summary->record_update_rs_time_ms(update_rs_time);
     body_summary->record_scan_rs_time_ms(scan_rs_time);
     body_summary->record_obj_copy_time_ms(obj_copy_time);
     if (parallel) {
       body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
       body_summary->record_termination_time_ms(termination_time);
       double parallel_known_time = known_time + termination_time;
       double parallel_other_time = _cur_collection_par_time_ms - parallel_known_time;
       body_summary->record_parallel_other_time_ms(parallel_other_time);
     }
     body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
     body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
     // We exempt parallel collection from this check because Alloc Buffer
     // fragmentation can produce negative collections.  Same with evac
     // failure.
     // Further, we're now always doing parallel collection.  But I'm still
     // leaving this here as a placeholder for a more precise assertion later.
     // (DLD, 10/05.
     assert((true || parallel)
            || _g1->evacuation_failed()
            || surviving_bytes <= _collection_set_bytes_used_before,
            "Or else negative collection!");
     // this is where we update the allocation rate of the application
     double app_time_ms =
       (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
     if (app_time_ms < MIN_TIMER_GRANULARITY) {
       // This usually happens due to the timer not having the required
       // granularity. Some Linuxes are the usual culprits.
       // We'll just set it to something (arbitrarily) small.
       app_time_ms = 1.0;
     }
     // We maintain the invariant that all objects allocated by mutator
     // threads will be allocated out of eden regions. So, we can use
     // the eden region number allocated since the previous GC to
     // calculate the application's allocate rate. The only exception
     // to that is humongous objects that are allocated separately. But
     // given that humongous object allocations do not really affect
     // either the pause's duration nor when the next pause will take
     // place we can safely ignore them here.
     size_t regions_allocated = eden_cset_region_length();
     double alloc_rate_ms = (double) regions_allocated / app_time_ms;
     _alloc_rate_ms_seq->add(alloc_rate_ms);
     double interval_ms =
       (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
     update_recent_gc_times(end_time_sec, elapsed_ms);
     _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
     if (recent_avg_pause_time_ratio() < 0.0 ||
         (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
 #ifndef PRODUCT
       // Dump info to allow post-facto debugging
       gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
       gclog_or_tty->print_cr("-------------------------------------------");
       gclog_or_tty->print_cr("Recent GC Times (ms):");
       _recent_gc_times_ms->dump();
       gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
       _recent_prev_end_times_for_all_gcs_sec->dump();
       gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
                              _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
       // In debug mode, terminate the JVM if the user wants to debug at this point.
       assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
 #endif  // !PRODUCT
       // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
       // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
       if (_recent_avg_pause_time_ratio < 0.0) {
         _recent_avg_pause_time_ratio = 0.0;
       } else {
         assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
         _recent_avg_pause_time_ratio = 1.0;
       }
     }
   }
   for (int i = 0; i < _aux_num; ++i) {
     if (_cur_aux_times_set[i]) {
       _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
     }
   }
   // PrintGCDetails output
   if (PrintGCDetails) {
     bool print_marking_info =
       _g1->mark_in_progress() && !last_pause_included_initial_mark;
     gclog_or_tty->print_cr("%s, %1.8lf secs]",
                            (last_pause_included_initial_mark) ? " (initial-mark)" : "",
                            elapsed_ms / 1000.0);
     if (parallel) {
       print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
       print_par_stats(2, "GC Worker Start", _par_last_gc_worker_start_times_ms);
       print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
       if (print_marking_info) {
         print_par_stats(2, "SATB Filtering", _par_last_satb_filtering_times_ms);
       }
       print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
       print_par_sizes(3, "Processed Buffers", _par_last_update_rs_processed_buffers);
       print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
       print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
       print_par_stats(2, "Termination", _par_last_termination_times_ms);
       print_par_sizes(3, "Termination Attempts", _par_last_termination_attempts);
       print_par_stats(2, "GC Worker End", _par_last_gc_worker_end_times_ms);
       for (int i = 0; i < _parallel_gc_threads; i++) {
         _par_last_gc_worker_times_ms[i] = _par_last_gc_worker_end_times_ms[i] - _par_last_gc_worker_start_times_ms[i];
         double worker_known_time = _par_last_ext_root_scan_times_ms[i] +
                                    _par_last_satb_filtering_times_ms[i] +
                                    _par_last_update_rs_times_ms[i] +
                                    _par_last_scan_rs_times_ms[i] +
                                    _par_last_obj_copy_times_ms[i] +
                                    _par_last_termination_times_ms[i];
         _par_last_gc_worker_other_times_ms[i] = _cur_collection_par_time_ms - worker_known_time;
       }
       print_par_stats(2, "GC Worker", _par_last_gc_worker_times_ms);
       print_par_stats(2, "GC Worker Other", _par_last_gc_worker_other_times_ms);
     } else {
       print_stats(1, "Ext Root Scanning", ext_root_scan_time);
       if (print_marking_info) {
         print_stats(1, "SATB Filtering", satb_filtering_time);
       }
       print_stats(1, "Update RS", update_rs_time);
       print_stats(2, "Processed Buffers", (int)update_rs_processed_buffers);
       print_stats(1, "Scan RS", scan_rs_time);
       print_stats(1, "Object Copying", obj_copy_time);
     }
     if (print_marking_info) {
       print_stats(1, "Complete CSet Marking", _mark_closure_time_ms);
     }
     print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
 #ifndef PRODUCT
     print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
     print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
     print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
     print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
     if (_num_cc_clears > 0) {
       print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
     }
 #endif
     print_stats(1, "Other", other_time_ms);
     print_stats(2, "Choose CSet",
                    (_recorded_young_cset_choice_time_ms +
                     _recorded_non_young_cset_choice_time_ms));
     print_stats(2, "Ref Proc", _cur_ref_proc_time_ms);
     print_stats(2, "Ref Enq", _cur_ref_enq_time_ms);
     print_stats(2, "Free CSet",
                    (_recorded_young_free_cset_time_ms +
                     _recorded_non_young_free_cset_time_ms));
     for (int i = 0; i < _aux_num; ++i) {
       if (_cur_aux_times_set[i]) {
         char buffer[96];
         sprintf(buffer, "Aux%d", i);
         print_stats(1, buffer, _cur_aux_times_ms[i]);
       }
     }
   }
   // Update the efficiency-since-mark vars.
   double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
   if (elapsed_ms < MIN_TIMER_GRANULARITY) {
     // This usually happens due to the timer not having the required
     // granularity. Some Linuxes are the usual culprits.
     // We'll just set it to something (arbitrarily) small.
     proc_ms = 1.0;
   }
   double cur_efficiency = (double) freed_bytes / proc_ms;
   bool new_in_marking_window = _in_marking_window;
   bool new_in_marking_window_im = false;
   if (during_initial_mark_pause()) {
     new_in_marking_window = true;
     new_in_marking_window_im = true;
   }
   if (_last_young_gc) {
     if (!last_pause_included_initial_mark) {
       ergo_verbose2(ErgoMixedGCs,
                     "start mixed GCs",
                     ergo_format_byte_perc("known garbage"),
                     _known_garbage_bytes, _known_garbage_ratio * 100.0);
       set_gcs_are_young(false);
     } else {
       ergo_verbose0(ErgoMixedGCs,
                     "do not start mixed GCs",
                     ergo_format_reason("concurrent cycle is about to start"));
     }
     _last_young_gc = false;
   }
   if (!_last_gc_was_young) {
     if (_should_revert_to_young_gcs) {
       ergo_verbose2(ErgoMixedGCs,
                     "end mixed GCs",
                     ergo_format_reason("mixed GCs end requested")
                     ergo_format_byte_perc("known garbage"),
                     _known_garbage_bytes, _known_garbage_ratio * 100.0);
       set_gcs_are_young(true);
     } else if (_known_garbage_ratio < 0.05) {
       ergo_verbose3(ErgoMixedGCs,
                "end mixed GCs",
                ergo_format_reason("known garbage percent lower than threshold")
                ergo_format_byte_perc("known garbage")
                ergo_format_perc("threshold"),
                _known_garbage_bytes, _known_garbage_ratio * 100.0,
 .05 * 100.0);
       set_gcs_are_young(true);
     } else if (adaptive_young_list_length() &&
               (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) {
       ergo_verbose5(ErgoMixedGCs,
                     "end mixed GCs",
                     ergo_format_reason("current GC efficiency lower than "
                                        "predicted young GC efficiency")
                     ergo_format_double("GC efficiency factor")
                     ergo_format_double("current GC efficiency")
                     ergo_format_double("predicted young GC efficiency")
                     ergo_format_byte_perc("known garbage"),
                     get_gc_eff_factor(), cur_efficiency,
                     predict_young_gc_eff(),
                     _known_garbage_bytes, _known_garbage_ratio * 100.0);
       set_gcs_are_young(true);
     }
   }
   _should_revert_to_young_gcs = false;
   if (_last_gc_was_young && !_during_marking) {
     _young_gc_eff_seq->add(cur_efficiency);
   }
   _short_lived_surv_rate_group->start_adding_regions();
   // do that for any other surv rate groupsx
   if (update_stats) {
     double pause_time_ms = elapsed_ms;
     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 = update_rs_time / (double) _pending_cards;
       _cost_per_card_ms_seq->add(cost_per_card_ms);
     }
     size_t cards_scanned = _g1->cards_scanned();
     double cost_per_entry_ms = 0.0;
     if (cards_scanned > 10) {
       cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
       if (_last_gc_was_young) {
         _cost_per_entry_ms_seq->add(cost_per_entry_ms);
       } else {
         _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
       }
     }
     if (_max_rs_lengths > 0) {
       double cards_per_entry_ratio =
         (double) cards_scanned / (double) _max_rs_lengths;
       if (_last_gc_was_young) {
         _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
       } else {
         _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
       }
     }
     // This is defensive. For a while _max_rs_lengths could get
     // smaller than _recorded_rs_lengths which was causing
     // rs_length_diff to get very large and mess up the RSet length
     // predictions. The reason was unsafe concurrent updates to the
     // _inc_cset_recorded_rs_lengths field which the code below guards
     // against (see CR 7118202). This bug has now been fixed (see CR
     // 7119027). However, I'm still worried that
     // _inc_cset_recorded_rs_lengths might still end up somewhat
     // inaccurate. The concurrent refinement thread calculates an
     // RSet's length concurrently with other CR threads updating it
     // which might cause it to calculate the length incorrectly (if,
     // say, it's in mid-coarsening). So I'll leave in the defensive
     // conditional below just in case.
     size_t rs_length_diff = 0;
     if (_max_rs_lengths > _recorded_rs_lengths) {
       rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
     }
     _rs_length_diff_seq->add((double) rs_length_diff);
     size_t copied_bytes = surviving_bytes;
     double cost_per_byte_ms = 0.0;
     if (copied_bytes > 0) {
       cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
       if (_in_marking_window) {
         _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
       } else {
         _cost_per_byte_ms_seq->add(cost_per_byte_ms);
       }
     }
     double all_other_time_ms = pause_time_ms -
       (update_rs_time + scan_rs_time + obj_copy_time +
        _mark_closure_time_ms + termination_time);
     double young_other_time_ms = 0.0;
     if (young_cset_region_length() > 0) {
       young_other_time_ms =
         _recorded_young_cset_choice_time_ms +
         _recorded_young_free_cset_time_ms;
       _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
                                           (double) young_cset_region_length());
     }
     double non_young_other_time_ms = 0.0;
     if (old_cset_region_length() > 0) {
       non_young_other_time_ms =
         _recorded_non_young_cset_choice_time_ms +
         _recorded_non_young_free_cset_time_ms;
       _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
                                             (double) old_cset_region_length());
     }
     double constant_other_time_ms = all_other_time_ms -
       (young_other_time_ms + non_young_other_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) {
       survival_ratio = (double) _bytes_copied_during_gc /
                                    (double) _bytes_in_collection_set_before_gc;
     }
     _pending_cards_seq->add((double) _pending_cards);
     _rs_lengths_seq->add((double) _max_rs_lengths);
     double expensive_region_limit_ms =
       (double) MaxGCPauseMillis - predict_constant_other_time_ms();
     if (expensive_region_limit_ms < 0.0) {
       // this means that the other time was predicted to be longer than
       // than the max pause time
       expensive_region_limit_ms = (double) MaxGCPauseMillis;
     }
     _expensive_region_limit_ms = expensive_region_limit_ms;
   }
   _in_marking_window = new_in_marking_window;
   _in_marking_window_im = new_in_marking_window_im;
   _free_regions_at_end_of_collection = _g1->free_regions();
   update_young_list_target_length();
   // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
   double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
   adjust_concurrent_refinement(update_rs_time, update_rs_processed_buffers, update_rs_time_goal_ms);
   assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
 }
 #define EXT_SIZE_FORMAT "%d%s"
 #define EXT_SIZE_PARAMS(bytes)                                  \
   byte_size_in_proper_unit((bytes)),                            \
   proper_unit_for_byte_size((bytes))
 void G1CollectorPolicy::print_heap_transition() {
   if (PrintGCDetails) {
     YoungList* young_list = _g1->young_list();
     size_t eden_bytes = young_list->eden_used_bytes();
     size_t survivor_bytes = young_list->survivor_used_bytes();
     size_t used_before_gc = _cur_collection_pause_used_at_start_bytes;
     size_t used = _g1->used();
     size_t capacity = _g1->capacity();
     size_t eden_capacity =
       (_young_list_target_length * HeapRegion::GrainBytes) - survivor_bytes;
     gclog_or_tty->print_cr(
       "   [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
       "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
       "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
       EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
       EXT_SIZE_PARAMS(_eden_bytes_before_gc),
       EXT_SIZE_PARAMS(_prev_eden_capacity),
       EXT_SIZE_PARAMS(eden_bytes),
       EXT_SIZE_PARAMS(eden_capacity),
       EXT_SIZE_PARAMS(_survivor_bytes_before_gc),
       EXT_SIZE_PARAMS(survivor_bytes),
       EXT_SIZE_PARAMS(used_before_gc),
       EXT_SIZE_PARAMS(_capacity_before_gc),
       EXT_SIZE_PARAMS(used),
       EXT_SIZE_PARAMS(capacity));
     _prev_eden_capacity = eden_capacity;
   } else if (PrintGC) {
     _g1->print_size_transition(gclog_or_tty,
                                _cur_collection_pause_used_at_start_bytes,
                                _g1->used(), _g1->capacity());
   }
 }
 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
                                                      double update_rs_processed_buffers,
                                                      double goal_ms) {
   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
   ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
   if (G1UseAdaptiveConcRefinement) {
     const int k_gy = 3, k_gr = 6;
     const double inc_k = 1.1, dec_k = 0.9;
     int g = cg1r->green_zone();
     if (update_rs_time > goal_ms) {
       g = (int)(g * dec_k);  // Can become 0, that's OK. That would mean a mutator-only processing.
     } else {
       if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
         g = (int)MAX2(g * inc_k, g + 1.0);
       }
     }
     // Change the refinement threads params
     cg1r->set_green_zone(g);
     cg1r->set_yellow_zone(g * k_gy);
     cg1r->set_red_zone(g * k_gr);
     cg1r->reinitialize_threads();
     int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
     int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
                                     cg1r->yellow_zone());
     // Change the barrier params
     dcqs.set_process_completed_threshold(processing_threshold);
     dcqs.set_max_completed_queue(cg1r->red_zone());
   }
   int curr_queue_size = dcqs.completed_buffers_num();
   if (curr_queue_size >= cg1r->yellow_zone()) {
     dcqs.set_completed_queue_padding(curr_queue_size);
   } else {
     dcqs.set_completed_queue_padding(0);
   }
   dcqs.notify_if_necessary();
 }
 double
 G1CollectorPolicy::
 predict_young_collection_elapsed_time_ms(size_t adjustment) {
   guarantee( adjustment == 0 || adjustment == 1, "invariant" );
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   size_t young_num = g1h->young_list()->length();
   if (young_num == 0)
     return 0.0;
   young_num += adjustment;
   size_t pending_cards = predict_pending_cards();
   size_t rs_lengths = g1h->young_list()->sampled_rs_lengths() +
                       predict_rs_length_diff();
   size_t card_num;
   if (gcs_are_young()) {
     card_num = predict_young_card_num(rs_lengths);
   } else {
     card_num = predict_non_young_card_num(rs_lengths);
   }
   size_t young_byte_size = young_num * HeapRegion::GrainBytes;
   double accum_yg_surv_rate =
     _short_lived_surv_rate_group->accum_surv_rate(adjustment);
   size_t bytes_to_copy =
     (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
   return
     predict_rs_update_time_ms(pending_cards) +
     predict_rs_scan_time_ms(card_num) +
     predict_object_copy_time_ms(bytes_to_copy) +
     predict_young_other_time_ms(young_num) +
     predict_constant_other_time_ms();
 }
 double
 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
   size_t rs_length = predict_rs_length_diff();
   size_t card_num;
   if (gcs_are_young()) {
     card_num = predict_young_card_num(rs_length);
   } else {
     card_num = predict_non_young_card_num(rs_length);
   }
   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();
 }
 double
 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
                                                   bool young) {
   size_t rs_length = hr->rem_set()->occupied();
   size_t card_num;
   if (gcs_are_young()) {
     card_num = predict_young_card_num(rs_length);
   } else {
     card_num = predict_non_young_card_num(rs_length);
   }
   size_t bytes_to_copy = predict_bytes_to_copy(hr);
   double region_elapsed_time_ms =
     predict_rs_scan_time_ms(card_num) +
     predict_object_copy_time_ms(bytes_to_copy);
   if (young)
     region_elapsed_time_ms += predict_young_other_time_ms(1);
   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 {
     guarantee( 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;
 }
 void
 G1CollectorPolicy::init_cset_region_lengths(size_t eden_cset_region_length,
                                           size_t survivor_cset_region_length) {
   _eden_cset_region_length     = eden_cset_region_length;
   _survivor_cset_region_length = survivor_cset_region_length;
   _old_cset_region_length      = 0;
 }
 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
   _recorded_rs_lengths = rs_lengths;
 }
 void G1CollectorPolicy::check_if_region_is_too_expensive(double
                                                            predicted_time_ms) {
   // I don't think we need to do this when in young GC mode since
   // marking will be initiated next time we hit the soft limit anyway...
   if (predicted_time_ms > _expensive_region_limit_ms) {
     ergo_verbose2(ErgoMixedGCs,
               "request mixed GCs end",
               ergo_format_reason("predicted region time higher than threshold")
               ergo_format_ms("predicted region time")
               ergo_format_ms("threshold"),
               predicted_time_ms, _expensive_region_limit_ms);
     // no point in doing another mixed GC
     _should_revert_to_young_gcs = true;
   }
 }
 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
                                                double elapsed_ms) {
   _recent_gc_times_ms->add(elapsed_ms);
   _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
   _prev_collection_pause_end_ms = end_time_sec * 1000.0;
 }
 size_t G1CollectorPolicy::expansion_amount() {
   double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
   double threshold = _gc_overhead_perc;
   if (recent_gc_overhead > threshold) {
     // We will double the existing space, or take
     // G1ExpandByPercentOfAvailable % of the available expansion
     // space, whichever is smaller, bounded below by a minimum
     // expansion (unless that's all that's left.)
     const size_t min_expand_bytes = 1*M;
     size_t reserved_bytes = _g1->max_capacity();
     size_t committed_bytes = _g1->capacity();
     size_t uncommitted_bytes = reserved_bytes - committed_bytes;
     size_t expand_bytes;
     size_t expand_bytes_via_pct =
       uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
     expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
     expand_bytes = MAX2(expand_bytes, min_expand_bytes);
     expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
     ergo_verbose5(ErgoHeapSizing,
                   "attempt heap expansion",
                   ergo_format_reason("recent GC overhead higher than "
                                      "threshold after GC")
                   ergo_format_perc("recent GC overhead")
                   ergo_format_perc("threshold")
                   ergo_format_byte("uncommitted")
                   ergo_format_byte_perc("calculated expansion amount"),
                   recent_gc_overhead, threshold,
                   uncommitted_bytes,
                   expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
     return expand_bytes;
   } else {
     return 0;
   }
 }
 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_summary(int level,
                                       const char* str,
                                       NumberSeq* seq) const {
   double sum = seq->sum();
   LineBuffer(level + 1).append_and_print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
                 str, sum / 1000.0, seq->avg());
 }
 void G1CollectorPolicy::print_summary_sd(int level,
                                          const char* str,
                                          NumberSeq* seq) const {
   print_summary(level, str, seq);
   LineBuffer(level + 6).append_and_print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
                 seq->num(), seq->sd(), seq->maximum());
 }
 void G1CollectorPolicy::check_other_times(int level,
                                         NumberSeq* other_times_ms,
                                         NumberSeq* calc_other_times_ms) const {
   bool should_print = false;
   LineBuffer buf(level + 2);
   double max_sum = MAX2(fabs(other_times_ms->sum()),
                         fabs(calc_other_times_ms->sum()));
   double min_sum = MIN2(fabs(other_times_ms->sum()),
                         fabs(calc_other_times_ms->sum()));
   double sum_ratio = max_sum / min_sum;
   if (sum_ratio > 1.1) {
     should_print = true;
     buf.append_and_print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
   }
   double max_avg = MAX2(fabs(other_times_ms->avg()),
                         fabs(calc_other_times_ms->avg()));
   double min_avg = MIN2(fabs(other_times_ms->avg()),
                         fabs(calc_other_times_ms->avg()));
   double avg_ratio = max_avg / min_avg;
   if (avg_ratio > 1.1) {
     should_print = true;
     buf.append_and_print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
   }
   if (other_times_ms->sum() < -0.01) {
     buf.append_and_print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
   }
   if (other_times_ms->avg() < -0.01) {
     buf.append_and_print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
   }
   if (calc_other_times_ms->sum() < -0.01) {
     should_print = true;
     buf.append_and_print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
   }
   if (calc_other_times_ms->avg() < -0.01) {
     should_print = true;
     buf.append_and_print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
   }
   if (should_print)
     print_summary(level, "Other(Calc)", calc_other_times_ms);
 }
 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
   bool parallel = G1CollectedHeap::use_parallel_gc_threads();
   MainBodySummary*    body_summary = summary->main_body_summary();
   if (summary->get_total_seq()->num() > 0) {
     print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
     if (body_summary != NULL) {
       if (parallel) {
         print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
         print_summary(2, "Ext Root Scanning", body_summary->get_ext_root_scan_seq());
         print_summary(2, "SATB Filtering", body_summary->get_satb_filtering_seq());
         print_summary(2, "Update RS", body_summary->get_update_rs_seq());
         print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
         print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
         print_summary(2, "Termination", body_summary->get_termination_seq());
         print_summary(2, "Parallel Other", body_summary->get_parallel_other_seq());
         {
           NumberSeq* other_parts[] = {
             body_summary->get_ext_root_scan_seq(),
             body_summary->get_satb_filtering_seq(),
             body_summary->get_update_rs_seq(),
             body_summary->get_scan_rs_seq(),
             body_summary->get_obj_copy_seq(),
             body_summary->get_termination_seq()
           };
           NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
 , other_parts);
           check_other_times(2, body_summary->get_parallel_other_seq(),
                             &calc_other_times_ms);
         }
       } else {
         print_summary(1, "Ext Root Scanning", body_summary->get_ext_root_scan_seq());
         print_summary(1, "SATB Filtering", body_summary->get_satb_filtering_seq());
         print_summary(1, "Update RS", body_summary->get_update_rs_seq());
         print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
         print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
       }
     }
     print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
     print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
     print_summary(1, "Other", summary->get_other_seq());
     {
       if (body_summary != NULL) {
         NumberSeq calc_other_times_ms;
         if (parallel) {
           // parallel
           NumberSeq* other_parts[] = {
             body_summary->get_satb_drain_seq(),
             body_summary->get_parallel_seq(),
             body_summary->get_clear_ct_seq()
           };
           calc_other_times_ms = NumberSeq(summary->get_total_seq(),
 , other_parts);
         } else {
           // serial
           NumberSeq* other_parts[] = {
             body_summary->get_satb_drain_seq(),
             body_summary->get_update_rs_seq(),
             body_summary->get_ext_root_scan_seq(),
             body_summary->get_satb_filtering_seq(),
             body_summary->get_scan_rs_seq(),
             body_summary->get_obj_copy_seq()
           };
           calc_other_times_ms = NumberSeq(summary->get_total_seq(),
 , other_parts);
         }
         check_other_times(1,  summary->get_other_seq(), &calc_other_times_ms);
       }
     }
   } else {
     LineBuffer(1).append_and_print_cr("none");
   }
   LineBuffer(0).append_and_print_cr("");
 }
 void G1CollectorPolicy::print_tracing_info() const {
   if (TraceGen0Time) {
     gclog_or_tty->print_cr("ALL PAUSES");
     print_summary_sd(0, "Total", _all_pause_times_ms);
     gclog_or_tty->print_cr("");
     gclog_or_tty->print_cr("");
     gclog_or_tty->print_cr("   Young GC Pauses: %8d", _young_pause_num);
     gclog_or_tty->print_cr("   Mixed GC Pauses: %8d", _mixed_pause_num);
     gclog_or_tty->print_cr("");
     gclog_or_tty->print_cr("EVACUATION PAUSES");
     print_summary(_summary);
     gclog_or_tty->print_cr("MISC");
     print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
     print_summary_sd(0, "Yields", _all_yield_times_ms);
     for (int i = 0; i < _aux_num; ++i) {
       if (_all_aux_times_ms[i].num() > 0) {
         char buffer[96];
         sprintf(buffer, "Aux%d", i);
         print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
       }
     }
   }
   if (TraceGen1Time) {
     if (_all_full_gc_times_ms->num() > 0) {
       gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
                  _all_full_gc_times_ms->num(),
                  _all_full_gc_times_ms->sum() / 1000.0);
       gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
       gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
                     _all_full_gc_times_ms->sd(),
                     _all_full_gc_times_ms->maximum());
     }
   }
 }
 void G1CollectorPolicy::print_yg_surv_rate_info() const {
 #ifndef PRODUCT
   _short_lived_surv_rate_group->print_surv_rate_summary();
   // add this call for any other surv rate groups
 #endif // PRODUCT
 }
 #ifndef PRODUCT
 // for debugging, bit of a hack...
 static char*
 region_num_to_mbs(int length) {
   static char buffer[64];
   double bytes = (double) (length * HeapRegion::GrainBytes);
   double mbs = bytes / (double) (1024 * 1024);
   sprintf(buffer, "%7.2lfMB", mbs);
   return buffer;
 }
 #endif // PRODUCT
 size_t G1CollectorPolicy::max_regions(int purpose) {
   switch (purpose) {
     case GCAllocForSurvived:
       return _max_survivor_regions;
     case GCAllocForTenured:
       return REGIONS_UNLIMITED;
     default:
       ShouldNotReachHere();
       return REGIONS_UNLIMITED;
   };
 }
 void G1CollectorPolicy::update_max_gc_locker_expansion() {
   size_t expansion_region_num = 0;
   if (GCLockerEdenExpansionPercent > 0) {
     double perc = (double) GCLockerEdenExpansionPercent / 100.0;
     double expansion_region_num_d = perc * (double) _young_list_target_length;
     // We use ceiling so that if expansion_region_num_d is > 0.0 (but
     // less than 1.0) we'll get 1.
     expansion_region_num = (size_t) ceil(expansion_region_num_d);
   } else {
     assert(expansion_region_num == 0, "sanity");
   }
   _young_list_max_length = _young_list_target_length + expansion_region_num;
   assert(_young_list_target_length <= _young_list_max_length, "post-condition");
 }
 // Calculates survivor space parameters.
 void G1CollectorPolicy::update_survivors_policy() {
   double max_survivor_regions_d =
                  (double) _young_list_target_length / (double) SurvivorRatio;
   // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
   // smaller than 1.0) we'll get 1.
   _max_survivor_regions = (size_t) ceil(max_survivor_regions_d);
   _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
         HeapRegion::GrainWords * _max_survivor_regions);
 }
 #ifndef PRODUCT
 class HRSortIndexIsOKClosure: public HeapRegionClosure {
   CollectionSetChooser* _chooser;
 public:
   HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
     _chooser(chooser) {}
   bool doHeapRegion(HeapRegion* r) {
     if (!r->continuesHumongous()) {
       assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
     }
     return false;
   }
 };
 bool G1CollectorPolicy::assertMarkedBytesDataOK() {
   HRSortIndexIsOKClosure cl(_collectionSetChooser);
   _g1->heap_region_iterate(&cl);
   return true;
 }
 #endif
 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
                                                      GCCause::Cause gc_cause) {
   bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
   if (!during_cycle) {
     ergo_verbose1(ErgoConcCycles,
                   "request concurrent cycle initiation",
                   ergo_format_reason("requested by GC cause")
                   ergo_format_str("GC cause"),
                   GCCause::to_string(gc_cause));
     set_initiate_conc_mark_if_possible();
     return true;
   } else {
     ergo_verbose1(ErgoConcCycles,
                   "do not request concurrent cycle initiation",
                   ergo_format_reason("concurrent cycle already in progress")
                   ergo_format_str("GC cause"),
                   GCCause::to_string(gc_cause));
     return false;
   }
 }
 void
 G1CollectorPolicy::decide_on_conc_mark_initiation() {
   // We are about to decide on whether this pause will be an
   // initial-mark pause.
   // First, during_initial_mark_pause() should not be already set. We
   // will set it here if we have to. However, it should be cleared by
   // the end of the pause (it's only set for the duration of an
   // initial-mark pause).
   assert(!during_initial_mark_pause(), "pre-condition");
   if (initiate_conc_mark_if_possible()) {
     // We had noticed on a previous pause that the heap occupancy has
     // gone over the initiating threshold and we should start a
     // concurrent marking cycle. So we might initiate one.
     bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
     if (!during_cycle) {
       // The concurrent marking thread is not "during a cycle", i.e.,
       // it has completed the last one. So we can go ahead and
       // initiate a new cycle.
       set_during_initial_mark_pause();
       // We do not allow mixed GCs during marking.
       if (!gcs_are_young()) {
         set_gcs_are_young(true);
         ergo_verbose0(ErgoMixedGCs,
                       "end mixed GCs",
                       ergo_format_reason("concurrent cycle is about to start"));
       }
       // And we can now clear initiate_conc_mark_if_possible() as
       // we've already acted on it.
       clear_initiate_conc_mark_if_possible();
       ergo_verbose0(ErgoConcCycles,
                   "initiate concurrent cycle",
                   ergo_format_reason("concurrent cycle initiation requested"));
     } else {
       // The concurrent marking thread is still finishing up the
       // previous cycle. If we start one right now the two cycles
       // overlap. In particular, the concurrent marking thread might
       // be in the process of clearing the next marking bitmap (which
       // we will use for the next cycle if we start one). Starting a
       // cycle now will be bad given that parts of the marking
       // information might get cleared by the marking thread. And we
       // cannot wait for the marking thread to finish the cycle as it
       // periodically yields while clearing the next marking bitmap
       // and, if it's in a yield point, it's waiting for us to
       // finish. So, at this point we will not start a cycle and we'll
       // let the concurrent marking thread complete the last one.
       ergo_verbose0(ErgoConcCycles,
                     "do not initiate concurrent cycle",
                     ergo_format_reason("concurrent cycle already in progress"));
     }
   }
 }
 class KnownGarbageClosure: public HeapRegionClosure {
   CollectionSetChooser* _hrSorted;
 public:
   KnownGarbageClosure(CollectionSetChooser* hrSorted) :
     _hrSorted(hrSorted)
   {}
   bool doHeapRegion(HeapRegion* r) {
     // We only include humongous regions in collection
     // sets when concurrent mark shows that their contained object is
     // unreachable.
     // Do we have any marking information for this region?
     if (r->is_marked()) {
       // We don't include humongous regions in collection
       // sets because we collect them immediately at the end of a marking
       // cycle.  We also don't include young regions because we *must*
       // include them in the next collection pause.
       if (!r->isHumongous() && !r->is_young()) {
         _hrSorted->addMarkedHeapRegion(r);
       }
     }
     return false;
   }
 };
 class ParKnownGarbageHRClosure: public HeapRegionClosure {
   CollectionSetChooser* _hrSorted;
   jint _marked_regions_added;
   jint _chunk_size;
   jint _cur_chunk_idx;
   jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
   int _worker;
   int _invokes;
   void get_new_chunk() {
     _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
     _cur_chunk_end = _cur_chunk_idx + _chunk_size;
   }
   void add_region(HeapRegion* r) {
     if (_cur_chunk_idx == _cur_chunk_end) {
       get_new_chunk();
     }
     assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
     _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
     _marked_regions_added++;
     _cur_chunk_idx++;
   }
 public:
   ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
                            jint chunk_size,
                            int worker) :
     _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
     _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
     _invokes(0)
   {}
   bool doHeapRegion(HeapRegion* r) {
     // We only include humongous regions in collection
     // sets when concurrent mark shows that their contained object is
     // unreachable.
     _invokes++;
     // Do we have any marking information for this region?
     if (r->is_marked()) {
       // We don't include humongous regions in collection
       // sets because we collect them immediately at the end of a marking
       // cycle.
       // We also do not include young regions in collection sets
       if (!r->isHumongous() && !r->is_young()) {
         add_region(r);
       }
     }
     return false;
   }
   jint marked_regions_added() { return _marked_regions_added; }
   int invokes() { return _invokes; }
 };
 class ParKnownGarbageTask: public AbstractGangTask {
   CollectionSetChooser* _hrSorted;
   jint _chunk_size;
   G1CollectedHeap* _g1;
 public:
   ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
     AbstractGangTask("ParKnownGarbageTask"),
     _hrSorted(hrSorted), _chunk_size(chunk_size),
     _g1(G1CollectedHeap::heap())
   {}
   void work(uint worker_id) {
     ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted,
                                                _chunk_size,
                                                worker_id);
     // Back to zero for the claim value.
     _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, worker_id,
                                          _g1->workers()->active_workers(),
                                          HeapRegion::InitialClaimValue);
     jint regions_added = parKnownGarbageCl.marked_regions_added();
     _hrSorted->incNumMarkedHeapRegions(regions_added);
     if (G1PrintParCleanupStats) {
       gclog_or_tty->print_cr("     Thread %d called %d times, added %d regions to list.",
                  worker_id, parKnownGarbageCl.invokes(), regions_added);
     }
   }
 };
 void
 G1CollectorPolicy::record_concurrent_mark_cleanup_end(int no_of_gc_threads) {
   double start_sec;
   if (G1PrintParCleanupStats) {
     start_sec = os::elapsedTime();
   }
   _collectionSetChooser->clearMarkedHeapRegions();
   double clear_marked_end_sec;
   if (G1PrintParCleanupStats) {
     clear_marked_end_sec = os::elapsedTime();
     gclog_or_tty->print_cr("  clear marked regions: %8.3f ms.",
                            (clear_marked_end_sec - start_sec) * 1000.0);
   }
   if (G1CollectedHeap::use_parallel_gc_threads()) {
     const size_t OverpartitionFactor = 4;
     size_t WorkUnit;
     // The use of MinChunkSize = 8 in the original code
     // causes some assertion failures when the total number of
     // region is less than 8.  The code here tries to fix that.
     // Should the original code also be fixed?
     if (no_of_gc_threads > 0) {
       const size_t MinWorkUnit =
         MAX2(_g1->n_regions() / no_of_gc_threads, (size_t) 1U);
       WorkUnit =
         MAX2(_g1->n_regions() / (no_of_gc_threads * OverpartitionFactor),
              MinWorkUnit);
     } else {
       assert(no_of_gc_threads > 0,
         "The active gc workers should be greater than 0");
       // In a product build do something reasonable to avoid a crash.
       const size_t MinWorkUnit =
         MAX2(_g1->n_regions() / ParallelGCThreads, (size_t) 1U);
       WorkUnit =
         MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
              MinWorkUnit);
     }
     _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
                                                              WorkUnit);
     ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
                                             (int) WorkUnit);
     _g1->workers()->run_task(&parKnownGarbageTask);
     assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
            "sanity check");
   } else {
     KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
     _g1->heap_region_iterate(&knownGarbagecl);
   }
   double known_garbage_end_sec;
   if (G1PrintParCleanupStats) {
     known_garbage_end_sec = os::elapsedTime();
     gclog_or_tty->print_cr("  compute known garbage: %8.3f ms.",
                       (known_garbage_end_sec - clear_marked_end_sec) * 1000.0);
   }
   _collectionSetChooser->sortMarkedHeapRegions();
   double end_sec = os::elapsedTime();
   if (G1PrintParCleanupStats) {
     gclog_or_tty->print_cr("  sorting: %8.3f ms.",
                            (end_sec - known_garbage_end_sec) * 1000.0);
   }
   double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
   _cur_mark_stop_world_time_ms += elapsed_time_ms;
   _prev_collection_pause_end_ms += elapsed_time_ms;
   _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true);
 }
 // Add the heap region at the head of the non-incremental collection set
 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
   assert(_inc_cset_build_state == Active, "Precondition");
   assert(!hr->is_young(), "non-incremental add of young region");
   assert(!hr->in_collection_set(), "should not already be in the CSet");
   hr->set_in_collection_set(true);
   hr->set_next_in_collection_set(_collection_set);
   _collection_set = hr;
   _collection_set_bytes_used_before += hr->used();
   _g1->register_region_with_in_cset_fast_test(hr);
   size_t rs_length = hr->rem_set()->occupied();
   _recorded_rs_lengths += rs_length;
   _old_cset_region_length += 1;
 }
 // Initialize the per-collection-set information
 void G1CollectorPolicy::start_incremental_cset_building() {
   assert(_inc_cset_build_state == Inactive, "Precondition");
   _inc_cset_head = NULL;
   _inc_cset_tail = NULL;
   _inc_cset_bytes_used_before = 0;
   _inc_cset_max_finger = 0;
   _inc_cset_recorded_rs_lengths = 0;
   _inc_cset_recorded_rs_lengths_diffs = 0;
   _inc_cset_predicted_elapsed_time_ms = 0.0;
   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
   _inc_cset_build_state = Active;
 }
 void G1CollectorPolicy::finalize_incremental_cset_building() {
   assert(_inc_cset_build_state == Active, "Precondition");
   assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
   // The two "main" fields, _inc_cset_recorded_rs_lengths and
   // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
   // that adds a new region to the CSet. Further updates by the
   // concurrent refinement thread that samples the young RSet lengths
   // are accumulated in the *_diffs fields. Here we add the diffs to
   // the "main" fields.
   if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
     _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
   } else {
     // This is defensive. The diff should in theory be always positive
     // as RSets can only grow between GCs. However, given that we
     // sample their size concurrently with other threads updating them
     // it's possible that we might get the wrong size back, which
     // could make the calculations somewhat inaccurate.
     size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
     if (_inc_cset_recorded_rs_lengths >= diffs) {
       _inc_cset_recorded_rs_lengths -= diffs;
     } else {
       _inc_cset_recorded_rs_lengths = 0;
     }
   }
   _inc_cset_predicted_elapsed_time_ms +=
                                      _inc_cset_predicted_elapsed_time_ms_diffs;
   _inc_cset_recorded_rs_lengths_diffs = 0;
   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
 }
 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
   // This routine is used when:
   // * adding survivor regions to the incremental cset at the end of an
   //   evacuation pause,
   // * adding the current allocation region to the incremental cset
   //   when it is retired, and
   // * updating existing policy information for a region in the
   //   incremental cset via young list RSet sampling.
   // Therefore this routine may be called at a safepoint by the
   // VM thread, or in-between safepoints by mutator threads (when
   // retiring the current allocation region) or a concurrent
   // refine thread (RSet sampling).
   double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
   size_t used_bytes = hr->used();
   _inc_cset_recorded_rs_lengths += rs_length;
   _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
   _inc_cset_bytes_used_before += used_bytes;
   // Cache the values we have added to the aggregated informtion
   // in the heap region in case we have to remove this region from
   // the incremental collection set, or it is updated by the
   // rset sampling code
   hr->set_recorded_rs_length(rs_length);
   hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
 }
 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
                                                      size_t new_rs_length) {
   // Update the CSet information that is dependent on the new RS length
   assert(hr->is_young(), "Precondition");
   assert(!SafepointSynchronize::is_at_safepoint(),
                                                "should not be at a safepoint");
   // We could have updated _inc_cset_recorded_rs_lengths and
   // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
   // that atomically, as this code is executed by a concurrent
   // refinement thread, potentially concurrently with a mutator thread
   // allocating a new region and also updating the same fields. To
   // avoid the atomic operations we accumulate these updates on two
   // separate fields (*_diffs) and we'll just add them to the "main"
   // fields at the start of a GC.
   ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
   ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
   _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 elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
   _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
   hr->set_recorded_rs_length(new_rs_length);
   hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
 }
 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
   assert(hr->is_young(), "invariant");
   assert(hr->young_index_in_cset() > -1, "should have already been set");
   assert(_inc_cset_build_state == Active, "Precondition");
   // We need to clear and set the cached recorded/cached collection set
   // information in the heap region here (before the region gets added
   // to the collection set). An individual heap region's cached values
   // are calculated, aggregated with the policy collection set info,
   // and cached in the heap region here (initially) and (subsequently)
   // by the Young List sampling code.
   size_t rs_length = hr->rem_set()->occupied();
   add_to_incremental_cset_info(hr, rs_length);
   HeapWord* hr_end = hr->end();
   _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
   assert(!hr->in_collection_set(), "invariant");
   hr->set_in_collection_set(true);
   assert( hr->next_in_collection_set() == NULL, "invariant");
   _g1->register_region_with_in_cset_fast_test(hr);
 }
 // Add the region at the RHS of the incremental cset
 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
   // We should only ever be appending survivors at the end of a pause
   assert( hr->is_survivor(), "Logic");
   // Do the 'common' stuff
   add_region_to_incremental_cset_common(hr);
   // Now add the region at the right hand side
   if (_inc_cset_tail == NULL) {
     assert(_inc_cset_head == NULL, "invariant");
     _inc_cset_head = hr;
   } else {
     _inc_cset_tail->set_next_in_collection_set(hr);
   }
   _inc_cset_tail = hr;
 }
 // Add the region to the LHS of the incremental cset
 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
   // Survivors should be added to the RHS at the end of a pause
   assert(!hr->is_survivor(), "Logic");
   // Do the 'common' stuff
   add_region_to_incremental_cset_common(hr);
   // Add the region at the left hand side
   hr->set_next_in_collection_set(_inc_cset_head);
   if (_inc_cset_head == NULL) {
     assert(_inc_cset_tail == NULL, "Invariant");
     _inc_cset_tail = hr;
   }
   _inc_cset_head = hr;
 }
 #ifndef PRODUCT
 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
   assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
   st->print_cr("\nCollection_set:");
   HeapRegion* csr = list_head;
   while (csr != NULL) {
     HeapRegion* next = csr->next_in_collection_set();
     assert(csr->in_collection_set(), "bad CS");
     st->print_cr("  [%08x-%08x], t: %08x, P: %08x, N: %08x, C: %08x, "
                  "age: %4d, y: %d, surv: %d",
                         csr->bottom(), csr->end(),
                         csr->top(),
                         csr->prev_top_at_mark_start(),
                         csr->next_top_at_mark_start(),
                         csr->top_at_conc_mark_count(),
                         csr->age_in_surv_rate_group_cond(),
                         csr->is_young(),
                         csr->is_survivor());
     csr = next;
   }
 }
 #endif // !PRODUCT
 void G1CollectorPolicy::choose_collection_set(double target_pause_time_ms) {
   // Set this here - in case we're not doing young collections.
   double non_young_start_time_sec = os::elapsedTime();
   YoungList* young_list = _g1->young_list();
   finalize_incremental_cset_building();
   guarantee(target_pause_time_ms > 0.0,
             err_msg("target_pause_time_ms = %1.6lf should be positive",
                     target_pause_time_ms));
   guarantee(_collection_set == NULL, "Precondition");
   double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
   double predicted_pause_time_ms = base_time_ms;
   double time_remaining_ms = target_pause_time_ms - base_time_ms;
   ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
                 "start choosing CSet",
                 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);
   // the 10% and 50% values are arbitrary...
   double threshold = 0.10 * target_pause_time_ms;
   if (time_remaining_ms < threshold) {
     double prev_time_remaining_ms = time_remaining_ms;
     time_remaining_ms = 0.50 * target_pause_time_ms;
     ergo_verbose3(ErgoCSetConstruction,
                   "adjust remaining time",
                   ergo_format_reason("remaining time lower than threshold")
                   ergo_format_ms("remaining time")
                   ergo_format_ms("threshold")
                   ergo_format_ms("adjusted remaining time"),
                   prev_time_remaining_ms, threshold, time_remaining_ms);
   }
   size_t expansion_bytes = _g1->expansion_regions() * HeapRegion::GrainBytes;
   HeapRegion* hr;
   double young_start_time_sec = os::elapsedTime();
   _collection_set_bytes_used_before = 0;
   _last_gc_was_young = gcs_are_young() ? true : false;
   if (_last_gc_was_young) {
     ++_young_pause_num;
   } else {
     ++_mixed_pause_num;
   }
   // The young list is laid with the survivor regions from the previous
   // pause are appended to the RHS of the young list, i.e.
   //   [Newly Young Regions ++ Survivors from last pause].
   size_t survivor_region_length = young_list->survivor_length();
   size_t 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();
   while (hr != NULL) {
     assert(hr->is_survivor(), "badly formed young list");
     hr->set_young();
     hr = hr->get_next_young_region();
   }
   // Clear the fields that point to the survivor list - they are all young now.
   young_list->clear_survivors();
   _collection_set = _inc_cset_head;
   _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
   time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms;
   predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
   ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
                 "add young regions to CSet",
                 ergo_format_region("eden")
                 ergo_format_region("survivors")
                 ergo_format_ms("predicted young region time"),
                 eden_region_length, survivor_region_length,
                 _inc_cset_predicted_elapsed_time_ms);
   // The number of recorded young regions is the incremental
   // collection set's current size
   set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
   double young_end_time_sec = os::elapsedTime();
   _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;
   if (!gcs_are_young()) {
     bool should_continue = true;
     NumberSeq seq;
     double avg_prediction = 100000000000000000.0; // something very large
     double prev_predicted_pause_time_ms = predicted_pause_time_ms;
     do {
       // Note that add_old_region_to_cset() increments the
       // _old_cset_region_length field and cset_region_length() returns the
       // sum of _eden_cset_region_length, _survivor_cset_region_length, and
       // _old_cset_region_length. So, as old regions are added to the
       // CSet, _old_cset_region_length will be incremented and
       // cset_region_length(), which is used below, will always reflect
       // the the total number of regions added up to this point to the CSet.
       hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
                                                       avg_prediction);
       if (hr != NULL) {
         _g1->old_set_remove(hr);
         double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
         time_remaining_ms -= predicted_time_ms;
         predicted_pause_time_ms += predicted_time_ms;
         add_old_region_to_cset(hr);
         seq.add(predicted_time_ms);
         avg_prediction = seq.avg() + seq.sd();
       }
       should_continue = true;
       if (hr == NULL) {
         // No need for an ergo verbose message here,
         // getNextMarkRegion() does this when it returns NULL.
         should_continue = false;
       } else {
         if (adaptive_young_list_length()) {
           if (time_remaining_ms < 0.0) {
             ergo_verbose1(ErgoCSetConstruction,
                           "stop adding old regions to CSet",
                           ergo_format_reason("remaining time is lower than 0")
                           ergo_format_ms("remaining time"),
                           time_remaining_ms);
             should_continue = false;
           }
         } else {
           if (cset_region_length() >= _young_list_fixed_length) {
             ergo_verbose2(ErgoCSetConstruction,
                           "stop adding old regions to CSet",
                           ergo_format_reason("CSet length reached target")
                           ergo_format_region("CSet")
                           ergo_format_region("young target"),
                           cset_region_length(), _young_list_fixed_length);
             should_continue = false;
           }
         }
       }
     } while (should_continue);
     if (!adaptive_young_list_length() &&
         cset_region_length() < _young_list_fixed_length) {
       ergo_verbose2(ErgoCSetConstruction,
                     "request mixed GCs end",
                     ergo_format_reason("CSet length lower than target")
                     ergo_format_region("CSet")
                     ergo_format_region("young target"),
                     cset_region_length(), _young_list_fixed_length);
       _should_revert_to_young_gcs  = true;
     }
     ergo_verbose2(ErgoCSetConstruction | ErgoHigh,
                   "add old regions to CSet",
                   ergo_format_region("old")
                   ergo_format_ms("predicted old region time"),
                   old_cset_region_length(),
                   predicted_pause_time_ms - prev_predicted_pause_time_ms);
   }
   stop_incremental_cset_building();
   count_CS_bytes_used();
   ergo_verbose5(ErgoCSetConstruction,
                 "finish choosing CSet",
                 ergo_format_region("eden")
                 ergo_format_region("survivors")
                 ergo_format_region("old")
                 ergo_format_ms("predicted pause time")
                 ergo_format_ms("target pause time"),
                 eden_region_length, survivor_region_length,
                 old_cset_region_length(),
                 predicted_pause_time_ms, target_pause_time_ms);
   double non_young_end_time_sec = os::elapsedTime();
   _recorded_non_young_cset_choice_time_ms =
     (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp@2ace1c4ee8da (annotated)

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