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

Tue, 23 Nov 2010 13:22:55 -0800

author
stefank
date
Tue, 23 Nov 2010 13:22:55 -0800
changeset 2314
f95d63e2154a
parent 2188
8b10f48633dc
child 2315
631f79e71e90
permissions
-rw-r--r--

6989984: Use standard include model for Hospot
Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg

     1 /*
     2  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 #include "precompiled.hpp"
    26 #include "gc_implementation/g1/concurrentG1Refine.hpp"
    27 #include "gc_implementation/g1/concurrentMark.hpp"
    28 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
    29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
    30 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
    31 #include "gc_implementation/g1/heapRegionRemSet.hpp"
    32 #include "gc_implementation/shared/gcPolicyCounters.hpp"
    33 #include "runtime/arguments.hpp"
    34 #include "runtime/java.hpp"
    35 #include "runtime/mutexLocker.hpp"
    36 #include "utilities/debug.hpp"
    38 #define PREDICTIONS_VERBOSE 0
    40 // <NEW PREDICTION>
    42 // Different defaults for different number of GC threads
    43 // They were chosen by running GCOld and SPECjbb on debris with different
    44 //   numbers of GC threads and choosing them based on the results
    46 // all the same
    47 static double rs_length_diff_defaults[] = {
    48   0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
    49 };
    51 static double cost_per_card_ms_defaults[] = {
    52   0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
    53 };
    55 // all the same
    56 static double fully_young_cards_per_entry_ratio_defaults[] = {
    57   1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
    58 };
    60 static double cost_per_entry_ms_defaults[] = {
    61   0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
    62 };
    64 static double cost_per_byte_ms_defaults[] = {
    65   0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
    66 };
    68 // these should be pretty consistent
    69 static double constant_other_time_ms_defaults[] = {
    70   5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
    71 };
    74 static double young_other_cost_per_region_ms_defaults[] = {
    75   0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
    76 };
    78 static double non_young_other_cost_per_region_ms_defaults[] = {
    79   1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
    80 };
    82 // </NEW PREDICTION>
    84 G1CollectorPolicy::G1CollectorPolicy() :
    85   _parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads()
    86     ? ParallelGCThreads : 1),
    89   _n_pauses(0),
    90   _recent_CH_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    91   _recent_G1_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    92   _recent_evac_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    93   _recent_pause_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    94   _recent_rs_sizes(new TruncatedSeq(NumPrevPausesForHeuristics)),
    95   _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    96   _all_pause_times_ms(new NumberSeq()),
    97   _stop_world_start(0.0),
    98   _all_stop_world_times_ms(new NumberSeq()),
    99   _all_yield_times_ms(new NumberSeq()),
   101   _all_mod_union_times_ms(new NumberSeq()),
   103   _summary(new Summary()),
   105 #ifndef PRODUCT
   106   _cur_clear_ct_time_ms(0.0),
   107   _min_clear_cc_time_ms(-1.0),
   108   _max_clear_cc_time_ms(-1.0),
   109   _cur_clear_cc_time_ms(0.0),
   110   _cum_clear_cc_time_ms(0.0),
   111   _num_cc_clears(0L),
   112 #endif
   114   _region_num_young(0),
   115   _region_num_tenured(0),
   116   _prev_region_num_young(0),
   117   _prev_region_num_tenured(0),
   119   _aux_num(10),
   120   _all_aux_times_ms(new NumberSeq[_aux_num]),
   121   _cur_aux_start_times_ms(new double[_aux_num]),
   122   _cur_aux_times_ms(new double[_aux_num]),
   123   _cur_aux_times_set(new bool[_aux_num]),
   125   _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   126   _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   127   _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   129   // <NEW PREDICTION>
   131   _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   132   _prev_collection_pause_end_ms(0.0),
   133   _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
   134   _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
   135   _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   136   _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
   137   _partially_young_cards_per_entry_ratio_seq(
   138                                          new TruncatedSeq(TruncatedSeqLength)),
   139   _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   140   _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   141   _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   142   _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
   143   _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   144   _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   145   _non_young_other_cost_per_region_ms_seq(
   146                                          new TruncatedSeq(TruncatedSeqLength)),
   148   _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
   149   _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
   150   _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
   152   _pause_time_target_ms((double) MaxGCPauseMillis),
   154   // </NEW PREDICTION>
   156   _in_young_gc_mode(false),
   157   _full_young_gcs(true),
   158   _full_young_pause_num(0),
   159   _partial_young_pause_num(0),
   161   _during_marking(false),
   162   _in_marking_window(false),
   163   _in_marking_window_im(false),
   165   _known_garbage_ratio(0.0),
   166   _known_garbage_bytes(0),
   168   _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
   170    _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
   172   _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
   173   _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
   175   _recent_avg_pause_time_ratio(0.0),
   176   _num_markings(0),
   177   _n_marks(0),
   178   _n_pauses_at_mark_end(0),
   180   _all_full_gc_times_ms(new NumberSeq()),
   182   // G1PausesBtwnConcMark defaults to -1
   183   // so the hack is to do the cast  QQQ FIXME
   184   _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
   185   _n_marks_since_last_pause(0),
   186   _initiate_conc_mark_if_possible(false),
   187   _during_initial_mark_pause(false),
   188   _should_revert_to_full_young_gcs(false),
   189   _last_full_young_gc(false),
   191   _prev_collection_pause_used_at_end_bytes(0),
   193   _collection_set(NULL),
   194   _collection_set_size(0),
   195   _collection_set_bytes_used_before(0),
   197   // Incremental CSet attributes
   198   _inc_cset_build_state(Inactive),
   199   _inc_cset_head(NULL),
   200   _inc_cset_tail(NULL),
   201   _inc_cset_size(0),
   202   _inc_cset_young_index(0),
   203   _inc_cset_bytes_used_before(0),
   204   _inc_cset_max_finger(NULL),
   205   _inc_cset_recorded_young_bytes(0),
   206   _inc_cset_recorded_rs_lengths(0),
   207   _inc_cset_predicted_elapsed_time_ms(0.0),
   208   _inc_cset_predicted_bytes_to_copy(0),
   210 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
   211 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
   212 #endif // _MSC_VER
   214   _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
   215                                                  G1YoungSurvRateNumRegionsSummary)),
   216   _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
   217                                               G1YoungSurvRateNumRegionsSummary)),
   218   // add here any more surv rate groups
   219   _recorded_survivor_regions(0),
   220   _recorded_survivor_head(NULL),
   221   _recorded_survivor_tail(NULL),
   222   _survivors_age_table(true),
   224   _gc_overhead_perc(0.0)
   226 {
   227   // Set up the region size and associated fields. Given that the
   228   // policy is created before the heap, we have to set this up here,
   229   // so it's done as soon as possible.
   230   HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
   231   HeapRegionRemSet::setup_remset_size();
   233   // Verify PLAB sizes
   234   const uint region_size = HeapRegion::GrainWords;
   235   if (YoungPLABSize > region_size || OldPLABSize > region_size) {
   236     char buffer[128];
   237     jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most %u",
   238                  OldPLABSize > region_size ? "Old" : "Young", region_size);
   239     vm_exit_during_initialization(buffer);
   240   }
   242   _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
   243   _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
   245   _par_last_gc_worker_start_times_ms = new double[_parallel_gc_threads];
   246   _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
   247   _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
   249   _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
   250   _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
   252   _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
   254   _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
   256   _par_last_termination_times_ms = new double[_parallel_gc_threads];
   257   _par_last_termination_attempts = new double[_parallel_gc_threads];
   258   _par_last_gc_worker_end_times_ms = new double[_parallel_gc_threads];
   260   // start conservatively
   261   _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
   263   // <NEW PREDICTION>
   265   int index;
   266   if (ParallelGCThreads == 0)
   267     index = 0;
   268   else if (ParallelGCThreads > 8)
   269     index = 7;
   270   else
   271     index = ParallelGCThreads - 1;
   273   _pending_card_diff_seq->add(0.0);
   274   _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
   275   _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
   276   _fully_young_cards_per_entry_ratio_seq->add(
   277                             fully_young_cards_per_entry_ratio_defaults[index]);
   278   _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
   279   _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
   280   _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
   281   _young_other_cost_per_region_ms_seq->add(
   282                                young_other_cost_per_region_ms_defaults[index]);
   283   _non_young_other_cost_per_region_ms_seq->add(
   284                            non_young_other_cost_per_region_ms_defaults[index]);
   286   // </NEW PREDICTION>
   288   // Below, we might need to calculate the pause time target based on
   289   // the pause interval. When we do so we are going to give G1 maximum
   290   // flexibility and allow it to do pauses when it needs to. So, we'll
   291   // arrange that the pause interval to be pause time target + 1 to
   292   // ensure that a) the pause time target is maximized with respect to
   293   // the pause interval and b) we maintain the invariant that pause
   294   // time target < pause interval. If the user does not want this
   295   // maximum flexibility, they will have to set the pause interval
   296   // explicitly.
   298   // First make sure that, if either parameter is set, its value is
   299   // reasonable.
   300   if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
   301     if (MaxGCPauseMillis < 1) {
   302       vm_exit_during_initialization("MaxGCPauseMillis should be "
   303                                     "greater than 0");
   304     }
   305   }
   306   if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
   307     if (GCPauseIntervalMillis < 1) {
   308       vm_exit_during_initialization("GCPauseIntervalMillis should be "
   309                                     "greater than 0");
   310     }
   311   }
   313   // Then, if the pause time target parameter was not set, set it to
   314   // the default value.
   315   if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
   316     if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
   317       // The default pause time target in G1 is 200ms
   318       FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
   319     } else {
   320       // We do not allow the pause interval to be set without the
   321       // pause time target
   322       vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
   323                                     "without setting MaxGCPauseMillis");
   324     }
   325   }
   327   // Then, if the interval parameter was not set, set it according to
   328   // the pause time target (this will also deal with the case when the
   329   // pause time target is the default value).
   330   if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
   331     FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
   332   }
   334   // Finally, make sure that the two parameters are consistent.
   335   if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
   336     char buffer[256];
   337     jio_snprintf(buffer, 256,
   338                  "MaxGCPauseMillis (%u) should be less than "
   339                  "GCPauseIntervalMillis (%u)",
   340                  MaxGCPauseMillis, GCPauseIntervalMillis);
   341     vm_exit_during_initialization(buffer);
   342   }
   344   double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
   345   double time_slice  = (double) GCPauseIntervalMillis / 1000.0;
   346   _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
   347   _sigma = (double) G1ConfidencePercent / 100.0;
   349   // start conservatively (around 50ms is about right)
   350   _concurrent_mark_init_times_ms->add(0.05);
   351   _concurrent_mark_remark_times_ms->add(0.05);
   352   _concurrent_mark_cleanup_times_ms->add(0.20);
   353   _tenuring_threshold = MaxTenuringThreshold;
   355   // if G1FixedSurvivorSpaceSize is 0 which means the size is not
   356   // fixed, then _max_survivor_regions will be calculated at
   357   // calculate_young_list_target_length during initialization
   358   _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
   360   assert(GCTimeRatio > 0,
   361          "we should have set it to a default value set_g1_gc_flags() "
   362          "if a user set it to 0");
   363   _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
   365   initialize_all();
   366 }
   368 // Increment "i", mod "len"
   369 static void inc_mod(int& i, int len) {
   370   i++; if (i == len) i = 0;
   371 }
   373 void G1CollectorPolicy::initialize_flags() {
   374   set_min_alignment(HeapRegion::GrainBytes);
   375   set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
   376   if (SurvivorRatio < 1) {
   377     vm_exit_during_initialization("Invalid survivor ratio specified");
   378   }
   379   CollectorPolicy::initialize_flags();
   380 }
   382 // The easiest way to deal with the parsing of the NewSize /
   383 // MaxNewSize / etc. parameteres is to re-use the code in the
   384 // TwoGenerationCollectorPolicy class. This is similar to what
   385 // ParallelScavenge does with its GenerationSizer class (see
   386 // ParallelScavengeHeap::initialize()). We might change this in the
   387 // future, but it's a good start.
   388 class G1YoungGenSizer : public TwoGenerationCollectorPolicy {
   389   size_t size_to_region_num(size_t byte_size) {
   390     return MAX2((size_t) 1, byte_size / HeapRegion::GrainBytes);
   391   }
   393 public:
   394   G1YoungGenSizer() {
   395     initialize_flags();
   396     initialize_size_info();
   397   }
   399   size_t min_young_region_num() {
   400     return size_to_region_num(_min_gen0_size);
   401   }
   402   size_t initial_young_region_num() {
   403     return size_to_region_num(_initial_gen0_size);
   404   }
   405   size_t max_young_region_num() {
   406     return size_to_region_num(_max_gen0_size);
   407   }
   408 };
   410 void G1CollectorPolicy::init() {
   411   // Set aside an initial future to_space.
   412   _g1 = G1CollectedHeap::heap();
   414   assert(Heap_lock->owned_by_self(), "Locking discipline.");
   416   initialize_gc_policy_counters();
   418   if (G1Gen) {
   419     _in_young_gc_mode = true;
   421     G1YoungGenSizer sizer;
   422     size_t initial_region_num = sizer.initial_young_region_num();
   424     if (UseAdaptiveSizePolicy) {
   425       set_adaptive_young_list_length(true);
   426       _young_list_fixed_length = 0;
   427     } else {
   428       set_adaptive_young_list_length(false);
   429       _young_list_fixed_length = initial_region_num;
   430     }
   431     _free_regions_at_end_of_collection = _g1->free_regions();
   432     calculate_young_list_min_length();
   433     guarantee( _young_list_min_length == 0, "invariant, not enough info" );
   434     calculate_young_list_target_length();
   435   } else {
   436      _young_list_fixed_length = 0;
   437     _in_young_gc_mode = false;
   438   }
   440   // We may immediately start allocating regions and placing them on the
   441   // collection set list. Initialize the per-collection set info
   442   start_incremental_cset_building();
   443 }
   445 // Create the jstat counters for the policy.
   446 void G1CollectorPolicy::initialize_gc_policy_counters()
   447 {
   448   _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen);
   449 }
   451 void G1CollectorPolicy::calculate_young_list_min_length() {
   452   _young_list_min_length = 0;
   454   if (!adaptive_young_list_length())
   455     return;
   457   if (_alloc_rate_ms_seq->num() > 3) {
   458     double now_sec = os::elapsedTime();
   459     double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
   460     double alloc_rate_ms = predict_alloc_rate_ms();
   461     int min_regions = (int) ceil(alloc_rate_ms * when_ms);
   462     int current_region_num = (int) _g1->young_list()->length();
   463     _young_list_min_length = min_regions + current_region_num;
   464   }
   465 }
   467 void G1CollectorPolicy::calculate_young_list_target_length() {
   468   if (adaptive_young_list_length()) {
   469     size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
   470     calculate_young_list_target_length(rs_lengths);
   471   } else {
   472     if (full_young_gcs())
   473       _young_list_target_length = _young_list_fixed_length;
   474     else
   475       _young_list_target_length = _young_list_fixed_length / 2;
   477     _young_list_target_length = MAX2(_young_list_target_length, (size_t)1);
   478   }
   479   calculate_survivors_policy();
   480 }
   482 void G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths) {
   483   guarantee( adaptive_young_list_length(), "pre-condition" );
   484   guarantee( !_in_marking_window || !_last_full_young_gc, "invariant" );
   486   double start_time_sec = os::elapsedTime();
   487   size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1ReservePercent);
   488   min_reserve_perc = MIN2((size_t) 50, min_reserve_perc);
   489   size_t reserve_regions =
   490     (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0);
   492   if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
   493     // we are in fully-young mode and there are free regions in the heap
   495     double survivor_regions_evac_time =
   496         predict_survivor_regions_evac_time();
   498     double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
   499     size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
   500     size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
   501     size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
   502     double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards)
   503                           + survivor_regions_evac_time;
   505     // the result
   506     size_t final_young_length = 0;
   508     size_t init_free_regions =
   509       MAX2((size_t)0, _free_regions_at_end_of_collection - reserve_regions);
   511     // if we're still under the pause target...
   512     if (base_time_ms <= target_pause_time_ms) {
   513       // We make sure that the shortest young length that makes sense
   514       // fits within the target pause time.
   515       size_t min_young_length = 1;
   517       if (predict_will_fit(min_young_length, base_time_ms,
   518                                      init_free_regions, target_pause_time_ms)) {
   519         // The shortest young length will fit within the target pause time;
   520         // we'll now check whether the absolute maximum number of young
   521         // regions will fit in the target pause time. If not, we'll do
   522         // a binary search between min_young_length and max_young_length
   523         size_t abs_max_young_length = _free_regions_at_end_of_collection - 1;
   524         size_t max_young_length = abs_max_young_length;
   526         if (max_young_length > min_young_length) {
   527           // Let's check if the initial max young length will fit within the
   528           // target pause. If so then there is no need to search for a maximal
   529           // young length - we'll return the initial maximum
   531           if (predict_will_fit(max_young_length, base_time_ms,
   532                                 init_free_regions, target_pause_time_ms)) {
   533             // The maximum young length will satisfy the target pause time.
   534             // We are done so set min young length to this maximum length.
   535             // The code after the loop will then set final_young_length using
   536             // the value cached in the minimum length.
   537             min_young_length = max_young_length;
   538           } else {
   539             // The maximum possible number of young regions will not fit within
   540             // the target pause time so let's search....
   542             size_t diff = (max_young_length - min_young_length) / 2;
   543             max_young_length = min_young_length + diff;
   545             while (max_young_length > min_young_length) {
   546               if (predict_will_fit(max_young_length, base_time_ms,
   547                                         init_free_regions, target_pause_time_ms)) {
   549                 // The current max young length will fit within the target
   550                 // pause time. Note we do not exit the loop here. By setting
   551                 // min = max, and then increasing the max below means that
   552                 // we will continue searching for an upper bound in the
   553                 // range [max..max+diff]
   554                 min_young_length = max_young_length;
   555               }
   556               diff = (max_young_length - min_young_length) / 2;
   557               max_young_length = min_young_length + diff;
   558             }
   559             // the above loop found a maximal young length that will fit
   560             // within the target pause time.
   561           }
   562           assert(min_young_length <= abs_max_young_length, "just checking");
   563         }
   564         final_young_length = min_young_length;
   565       }
   566     }
   567     // and we're done!
   569     // we should have at least one region in the target young length
   570     _young_list_target_length =
   571         MAX2((size_t) 1, final_young_length + _recorded_survivor_regions);
   573     // let's keep an eye of how long we spend on this calculation
   574     // right now, I assume that we'll print it when we need it; we
   575     // should really adde it to the breakdown of a pause
   576     double end_time_sec = os::elapsedTime();
   577     double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
   579 #ifdef TRACE_CALC_YOUNG_LENGTH
   580     // leave this in for debugging, just in case
   581     gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT ", "
   582                            "elapsed %1.2lf ms, (%s%s) " SIZE_FORMAT SIZE_FORMAT,
   583                            target_pause_time_ms,
   584                            _young_list_target_length
   585                            elapsed_time_ms,
   586                            full_young_gcs() ? "full" : "partial",
   587                            during_initial_mark_pause() ? " i-m" : "",
   588                            _in_marking_window,
   589                            _in_marking_window_im);
   590 #endif // TRACE_CALC_YOUNG_LENGTH
   592     if (_young_list_target_length < _young_list_min_length) {
   593       // bummer; this means that, if we do a pause when the maximal
   594       // length dictates, we'll violate the pause spacing target (the
   595       // min length was calculate based on the application's current
   596       // alloc rate);
   598       // so, we have to bite the bullet, and allocate the minimum
   599       // number. We'll violate our target, but we just can't meet it.
   601 #ifdef TRACE_CALC_YOUNG_LENGTH
   602       // leave this in for debugging, just in case
   603       gclog_or_tty->print_cr("adjusted target length from "
   604                              SIZE_FORMAT " to " SIZE_FORMAT,
   605                              _young_list_target_length, _young_list_min_length);
   606 #endif // TRACE_CALC_YOUNG_LENGTH
   608       _young_list_target_length = _young_list_min_length;
   609     }
   610   } else {
   611     // we are in a partially-young mode or we've run out of regions (due
   612     // to evacuation failure)
   614 #ifdef TRACE_CALC_YOUNG_LENGTH
   615     // leave this in for debugging, just in case
   616     gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
   617                            _young_list_min_length);
   618 #endif // TRACE_CALC_YOUNG_LENGTH
   619     // we'll do the pause as soon as possible by choosing the minimum
   620     _young_list_target_length =
   621       MAX2(_young_list_min_length, (size_t) 1);
   622   }
   624   _rs_lengths_prediction = rs_lengths;
   625 }
   627 // This is used by: calculate_young_list_target_length(rs_length). It
   628 // returns true iff:
   629 //   the predicted pause time for the given young list will not overflow
   630 //   the target pause time
   631 // and:
   632 //   the predicted amount of surviving data will not overflow the
   633 //   the amount of free space available for survivor regions.
   634 //
   635 bool
   636 G1CollectorPolicy::predict_will_fit(size_t young_length,
   637                                     double base_time_ms,
   638                                     size_t init_free_regions,
   639                                     double target_pause_time_ms) {
   641   if (young_length >= init_free_regions)
   642     // end condition 1: not enough space for the young regions
   643     return false;
   645   double accum_surv_rate_adj = 0.0;
   646   double accum_surv_rate =
   647     accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
   649   size_t bytes_to_copy =
   650     (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
   652   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
   654   double young_other_time_ms =
   655                        predict_young_other_time_ms(young_length);
   657   double pause_time_ms =
   658                    base_time_ms + copy_time_ms + young_other_time_ms;
   660   if (pause_time_ms > target_pause_time_ms)
   661     // end condition 2: over the target pause time
   662     return false;
   664   size_t free_bytes =
   665                  (init_free_regions - young_length) * HeapRegion::GrainBytes;
   667   if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes)
   668     // end condition 3: out of to-space (conservatively)
   669     return false;
   671   // success!
   672   return true;
   673 }
   675 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
   676   double survivor_regions_evac_time = 0.0;
   677   for (HeapRegion * r = _recorded_survivor_head;
   678        r != NULL && r != _recorded_survivor_tail->get_next_young_region();
   679        r = r->get_next_young_region()) {
   680     survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
   681   }
   682   return survivor_regions_evac_time;
   683 }
   685 void G1CollectorPolicy::check_prediction_validity() {
   686   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
   688   size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
   689   if (rs_lengths > _rs_lengths_prediction) {
   690     // add 10% to avoid having to recalculate often
   691     size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
   692     calculate_young_list_target_length(rs_lengths_prediction);
   693   }
   694 }
   696 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
   697                                                bool is_tlab,
   698                                                bool* gc_overhead_limit_was_exceeded) {
   699   guarantee(false, "Not using this policy feature yet.");
   700   return NULL;
   701 }
   703 // This method controls how a collector handles one or more
   704 // of its generations being fully allocated.
   705 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
   706                                                        bool is_tlab) {
   707   guarantee(false, "Not using this policy feature yet.");
   708   return NULL;
   709 }
   712 #ifndef PRODUCT
   713 bool G1CollectorPolicy::verify_young_ages() {
   714   HeapRegion* head = _g1->young_list()->first_region();
   715   return
   716     verify_young_ages(head, _short_lived_surv_rate_group);
   717   // also call verify_young_ages on any additional surv rate groups
   718 }
   720 bool
   721 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
   722                                      SurvRateGroup *surv_rate_group) {
   723   guarantee( surv_rate_group != NULL, "pre-condition" );
   725   const char* name = surv_rate_group->name();
   726   bool ret = true;
   727   int prev_age = -1;
   729   for (HeapRegion* curr = head;
   730        curr != NULL;
   731        curr = curr->get_next_young_region()) {
   732     SurvRateGroup* group = curr->surv_rate_group();
   733     if (group == NULL && !curr->is_survivor()) {
   734       gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
   735       ret = false;
   736     }
   738     if (surv_rate_group == group) {
   739       int age = curr->age_in_surv_rate_group();
   741       if (age < 0) {
   742         gclog_or_tty->print_cr("## %s: encountered negative age", name);
   743         ret = false;
   744       }
   746       if (age <= prev_age) {
   747         gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
   748                                "(%d, %d)", name, age, prev_age);
   749         ret = false;
   750       }
   751       prev_age = age;
   752     }
   753   }
   755   return ret;
   756 }
   757 #endif // PRODUCT
   759 void G1CollectorPolicy::record_full_collection_start() {
   760   _cur_collection_start_sec = os::elapsedTime();
   761   // Release the future to-space so that it is available for compaction into.
   762   _g1->set_full_collection();
   763 }
   765 void G1CollectorPolicy::record_full_collection_end() {
   766   // Consider this like a collection pause for the purposes of allocation
   767   // since last pause.
   768   double end_sec = os::elapsedTime();
   769   double full_gc_time_sec = end_sec - _cur_collection_start_sec;
   770   double full_gc_time_ms = full_gc_time_sec * 1000.0;
   772   _all_full_gc_times_ms->add(full_gc_time_ms);
   774   update_recent_gc_times(end_sec, full_gc_time_ms);
   776   _g1->clear_full_collection();
   778   // "Nuke" the heuristics that control the fully/partially young GC
   779   // transitions and make sure we start with fully young GCs after the
   780   // Full GC.
   781   set_full_young_gcs(true);
   782   _last_full_young_gc = false;
   783   _should_revert_to_full_young_gcs = false;
   784   clear_initiate_conc_mark_if_possible();
   785   clear_during_initial_mark_pause();
   786   _known_garbage_bytes = 0;
   787   _known_garbage_ratio = 0.0;
   788   _in_marking_window = false;
   789   _in_marking_window_im = false;
   791   _short_lived_surv_rate_group->start_adding_regions();
   792   // also call this on any additional surv rate groups
   794   record_survivor_regions(0, NULL, NULL);
   796   _prev_region_num_young   = _region_num_young;
   797   _prev_region_num_tenured = _region_num_tenured;
   799   _free_regions_at_end_of_collection = _g1->free_regions();
   800   // Reset survivors SurvRateGroup.
   801   _survivor_surv_rate_group->reset();
   802   calculate_young_list_min_length();
   803   calculate_young_list_target_length();
   804  }
   806 void G1CollectorPolicy::record_before_bytes(size_t bytes) {
   807   _bytes_in_to_space_before_gc += bytes;
   808 }
   810 void G1CollectorPolicy::record_after_bytes(size_t bytes) {
   811   _bytes_in_to_space_after_gc += bytes;
   812 }
   814 void G1CollectorPolicy::record_stop_world_start() {
   815   _stop_world_start = os::elapsedTime();
   816 }
   818 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
   819                                                       size_t start_used) {
   820   if (PrintGCDetails) {
   821     gclog_or_tty->stamp(PrintGCTimeStamps);
   822     gclog_or_tty->print("[GC pause");
   823     if (in_young_gc_mode())
   824       gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
   825   }
   827   assert(_g1->used_regions() == _g1->recalculate_used_regions(),
   828          "sanity");
   829   assert(_g1->used() == _g1->recalculate_used(), "sanity");
   831   double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
   832   _all_stop_world_times_ms->add(s_w_t_ms);
   833   _stop_world_start = 0.0;
   835   _cur_collection_start_sec = start_time_sec;
   836   _cur_collection_pause_used_at_start_bytes = start_used;
   837   _cur_collection_pause_used_regions_at_start = _g1->used_regions();
   838   _pending_cards = _g1->pending_card_num();
   839   _max_pending_cards = _g1->max_pending_card_num();
   841   _bytes_in_to_space_before_gc = 0;
   842   _bytes_in_to_space_after_gc = 0;
   843   _bytes_in_collection_set_before_gc = 0;
   845 #ifdef DEBUG
   846   // initialise these to something well known so that we can spot
   847   // if they are not set properly
   849   for (int i = 0; i < _parallel_gc_threads; ++i) {
   850     _par_last_gc_worker_start_times_ms[i] = -1234.0;
   851     _par_last_ext_root_scan_times_ms[i] = -1234.0;
   852     _par_last_mark_stack_scan_times_ms[i] = -1234.0;
   853     _par_last_update_rs_times_ms[i] = -1234.0;
   854     _par_last_update_rs_processed_buffers[i] = -1234.0;
   855     _par_last_scan_rs_times_ms[i] = -1234.0;
   856     _par_last_obj_copy_times_ms[i] = -1234.0;
   857     _par_last_termination_times_ms[i] = -1234.0;
   858     _par_last_termination_attempts[i] = -1234.0;
   859     _par_last_gc_worker_end_times_ms[i] = -1234.0;
   860   }
   861 #endif
   863   for (int i = 0; i < _aux_num; ++i) {
   864     _cur_aux_times_ms[i] = 0.0;
   865     _cur_aux_times_set[i] = false;
   866   }
   868   _satb_drain_time_set = false;
   869   _last_satb_drain_processed_buffers = -1;
   871   if (in_young_gc_mode())
   872     _last_young_gc_full = false;
   874   // do that for any other surv rate groups
   875   _short_lived_surv_rate_group->stop_adding_regions();
   876   _survivors_age_table.clear();
   878   assert( verify_young_ages(), "region age verification" );
   879 }
   881 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
   882   _mark_closure_time_ms = mark_closure_time_ms;
   883 }
   885 void G1CollectorPolicy::record_concurrent_mark_init_start() {
   886   _mark_init_start_sec = os::elapsedTime();
   887   guarantee(!in_young_gc_mode(), "should not do be here in young GC mode");
   888 }
   890 void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double
   891                                                    mark_init_elapsed_time_ms) {
   892   _during_marking = true;
   893   assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
   894   clear_during_initial_mark_pause();
   895   _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
   896 }
   898 void G1CollectorPolicy::record_concurrent_mark_init_end() {
   899   double end_time_sec = os::elapsedTime();
   900   double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
   901   _concurrent_mark_init_times_ms->add(elapsed_time_ms);
   902   record_concurrent_mark_init_end_pre(elapsed_time_ms);
   904   _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true);
   905 }
   907 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
   908   _mark_remark_start_sec = os::elapsedTime();
   909   _during_marking = false;
   910 }
   912 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
   913   double end_time_sec = os::elapsedTime();
   914   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
   915   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
   916   _cur_mark_stop_world_time_ms += elapsed_time_ms;
   917   _prev_collection_pause_end_ms += elapsed_time_ms;
   919   _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
   920 }
   922 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
   923   _mark_cleanup_start_sec = os::elapsedTime();
   924 }
   926 void
   927 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
   928                                                       size_t max_live_bytes) {
   929   record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
   930   record_concurrent_mark_cleanup_end_work2();
   931 }
   933 void
   934 G1CollectorPolicy::
   935 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
   936                                          size_t max_live_bytes) {
   937   if (_n_marks < 2) _n_marks++;
   938   if (G1PolicyVerbose > 0)
   939     gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB "
   940                            " (of " SIZE_FORMAT " MB heap).",
   941                            max_live_bytes/M, _g1->capacity()/M);
   942 }
   944 // The important thing about this is that it includes "os::elapsedTime".
   945 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
   946   double end_time_sec = os::elapsedTime();
   947   double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
   948   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
   949   _cur_mark_stop_world_time_ms += elapsed_time_ms;
   950   _prev_collection_pause_end_ms += elapsed_time_ms;
   952   _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
   954   _num_markings++;
   956   // We did a marking, so reset the "since_last_mark" variables.
   957   double considerConcMarkCost = 1.0;
   958   // If there are available processors, concurrent activity is free...
   959   if (Threads::number_of_non_daemon_threads() * 2 <
   960       os::active_processor_count()) {
   961     considerConcMarkCost = 0.0;
   962   }
   963   _n_pauses_at_mark_end = _n_pauses;
   964   _n_marks_since_last_pause++;
   965 }
   967 void
   968 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
   969   if (in_young_gc_mode()) {
   970     _should_revert_to_full_young_gcs = false;
   971     _last_full_young_gc = true;
   972     _in_marking_window = false;
   973     if (adaptive_young_list_length())
   974       calculate_young_list_target_length();
   975   }
   976 }
   978 void G1CollectorPolicy::record_concurrent_pause() {
   979   if (_stop_world_start > 0.0) {
   980     double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
   981     _all_yield_times_ms->add(yield_ms);
   982   }
   983 }
   985 void G1CollectorPolicy::record_concurrent_pause_end() {
   986 }
   988 void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() {
   989   _cur_CH_strong_roots_end_sec = os::elapsedTime();
   990   _cur_CH_strong_roots_dur_ms =
   991     (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0;
   992 }
   994 void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() {
   995   _cur_G1_strong_roots_end_sec = os::elapsedTime();
   996   _cur_G1_strong_roots_dur_ms =
   997     (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0;
   998 }
  1000 template<class T>
  1001 T sum_of(T* sum_arr, int start, int n, int N) {
  1002   T sum = (T)0;
  1003   for (int i = 0; i < n; i++) {
  1004     int j = (start + i) % N;
  1005     sum += sum_arr[j];
  1007   return sum;
  1010 void G1CollectorPolicy::print_par_stats(int level,
  1011                                         const char* str,
  1012                                         double* data,
  1013                                          bool summary) {
  1014   double min = data[0], max = data[0];
  1015   double total = 0.0;
  1016   int j;
  1017   for (j = 0; j < level; ++j)
  1018     gclog_or_tty->print("   ");
  1019   gclog_or_tty->print("[%s (ms):", str);
  1020   for (uint i = 0; i < ParallelGCThreads; ++i) {
  1021     double val = data[i];
  1022     if (val < min)
  1023       min = val;
  1024     if (val > max)
  1025       max = val;
  1026     total += val;
  1027     gclog_or_tty->print("  %3.1lf", val);
  1029   if (summary) {
  1030     gclog_or_tty->print_cr("");
  1031     double avg = total / (double) ParallelGCThreads;
  1032     gclog_or_tty->print(" ");
  1033     for (j = 0; j < level; ++j)
  1034       gclog_or_tty->print("   ");
  1035     gclog_or_tty->print("Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf",
  1036                         avg, min, max);
  1038   gclog_or_tty->print_cr("]");
  1041 void G1CollectorPolicy::print_par_sizes(int level,
  1042                                         const char* str,
  1043                                         double* data,
  1044                                         bool summary) {
  1045   double min = data[0], max = data[0];
  1046   double total = 0.0;
  1047   int j;
  1048   for (j = 0; j < level; ++j)
  1049     gclog_or_tty->print("   ");
  1050   gclog_or_tty->print("[%s :", str);
  1051   for (uint i = 0; i < ParallelGCThreads; ++i) {
  1052     double val = data[i];
  1053     if (val < min)
  1054       min = val;
  1055     if (val > max)
  1056       max = val;
  1057     total += val;
  1058     gclog_or_tty->print(" %d", (int) val);
  1060   if (summary) {
  1061     gclog_or_tty->print_cr("");
  1062     double avg = total / (double) ParallelGCThreads;
  1063     gclog_or_tty->print(" ");
  1064     for (j = 0; j < level; ++j)
  1065       gclog_or_tty->print("   ");
  1066     gclog_or_tty->print("Sum: %d, Avg: %d, Min: %d, Max: %d",
  1067                (int)total, (int)avg, (int)min, (int)max);
  1069   gclog_or_tty->print_cr("]");
  1072 void G1CollectorPolicy::print_stats (int level,
  1073                                      const char* str,
  1074                                      double value) {
  1075   for (int j = 0; j < level; ++j)
  1076     gclog_or_tty->print("   ");
  1077   gclog_or_tty->print_cr("[%s: %5.1lf ms]", str, value);
  1080 void G1CollectorPolicy::print_stats (int level,
  1081                                      const char* str,
  1082                                      int value) {
  1083   for (int j = 0; j < level; ++j)
  1084     gclog_or_tty->print("   ");
  1085   gclog_or_tty->print_cr("[%s: %d]", str, value);
  1088 double G1CollectorPolicy::avg_value (double* data) {
  1089   if (G1CollectedHeap::use_parallel_gc_threads()) {
  1090     double ret = 0.0;
  1091     for (uint i = 0; i < ParallelGCThreads; ++i)
  1092       ret += data[i];
  1093     return ret / (double) ParallelGCThreads;
  1094   } else {
  1095     return data[0];
  1099 double G1CollectorPolicy::max_value (double* data) {
  1100   if (G1CollectedHeap::use_parallel_gc_threads()) {
  1101     double ret = data[0];
  1102     for (uint i = 1; i < ParallelGCThreads; ++i)
  1103       if (data[i] > ret)
  1104         ret = data[i];
  1105     return ret;
  1106   } else {
  1107     return data[0];
  1111 double G1CollectorPolicy::sum_of_values (double* data) {
  1112   if (G1CollectedHeap::use_parallel_gc_threads()) {
  1113     double sum = 0.0;
  1114     for (uint i = 0; i < ParallelGCThreads; i++)
  1115       sum += data[i];
  1116     return sum;
  1117   } else {
  1118     return data[0];
  1122 double G1CollectorPolicy::max_sum (double* data1,
  1123                                    double* data2) {
  1124   double ret = data1[0] + data2[0];
  1126   if (G1CollectedHeap::use_parallel_gc_threads()) {
  1127     for (uint i = 1; i < ParallelGCThreads; ++i) {
  1128       double data = data1[i] + data2[i];
  1129       if (data > ret)
  1130         ret = data;
  1133   return ret;
  1136 // Anything below that is considered to be zero
  1137 #define MIN_TIMER_GRANULARITY 0.0000001
  1139 void G1CollectorPolicy::record_collection_pause_end() {
  1140   double end_time_sec = os::elapsedTime();
  1141   double elapsed_ms = _last_pause_time_ms;
  1142   bool parallel = G1CollectedHeap::use_parallel_gc_threads();
  1143   double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0;
  1144   size_t rs_size =
  1145     _cur_collection_pause_used_regions_at_start - collection_set_size();
  1146   size_t cur_used_bytes = _g1->used();
  1147   assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
  1148   bool last_pause_included_initial_mark = false;
  1149   bool update_stats = !_g1->evacuation_failed();
  1151 #ifndef PRODUCT
  1152   if (G1YoungSurvRateVerbose) {
  1153     gclog_or_tty->print_cr("");
  1154     _short_lived_surv_rate_group->print();
  1155     // do that for any other surv rate groups too
  1157 #endif // PRODUCT
  1159   if (in_young_gc_mode()) {
  1160     last_pause_included_initial_mark = during_initial_mark_pause();
  1161     if (last_pause_included_initial_mark)
  1162       record_concurrent_mark_init_end_pre(0.0);
  1164     size_t min_used_targ =
  1165       (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
  1168     if (!_g1->mark_in_progress() && !_last_full_young_gc) {
  1169       assert(!last_pause_included_initial_mark, "invariant");
  1170       if (cur_used_bytes > min_used_targ &&
  1171           cur_used_bytes > _prev_collection_pause_used_at_end_bytes) {
  1172         assert(!during_initial_mark_pause(), "we should not see this here");
  1174         // Note: this might have already been set, if during the last
  1175         // pause we decided to start a cycle but at the beginning of
  1176         // this pause we decided to postpone it. That's OK.
  1177         set_initiate_conc_mark_if_possible();
  1181     _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
  1184   _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
  1185                           end_time_sec, false);
  1187   guarantee(_cur_collection_pause_used_regions_at_start >=
  1188             collection_set_size(),
  1189             "Negative RS size?");
  1191   // This assert is exempted when we're doing parallel collection pauses,
  1192   // because the fragmentation caused by the parallel GC allocation buffers
  1193   // can lead to more memory being used during collection than was used
  1194   // before. Best leave this out until the fragmentation problem is fixed.
  1195   // Pauses in which evacuation failed can also lead to negative
  1196   // collections, since no space is reclaimed from a region containing an
  1197   // object whose evacuation failed.
  1198   // Further, we're now always doing parallel collection.  But I'm still
  1199   // leaving this here as a placeholder for a more precise assertion later.
  1200   // (DLD, 10/05.)
  1201   assert((true || parallel) // Always using GC LABs now.
  1202          || _g1->evacuation_failed()
  1203          || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
  1204          "Negative collection");
  1206   size_t freed_bytes =
  1207     _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
  1208   size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
  1210   double survival_fraction =
  1211     (double)surviving_bytes/
  1212     (double)_collection_set_bytes_used_before;
  1214   _n_pauses++;
  1216   if (update_stats) {
  1217     _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms);
  1218     _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms);
  1219     _recent_evac_times_ms->add(evac_ms);
  1220     _recent_pause_times_ms->add(elapsed_ms);
  1222     _recent_rs_sizes->add(rs_size);
  1224     // We exempt parallel collection from this check because Alloc Buffer
  1225     // fragmentation can produce negative collections.  Same with evac
  1226     // failure.
  1227     // Further, we're now always doing parallel collection.  But I'm still
  1228     // leaving this here as a placeholder for a more precise assertion later.
  1229     // (DLD, 10/05.
  1230     assert((true || parallel)
  1231            || _g1->evacuation_failed()
  1232            || surviving_bytes <= _collection_set_bytes_used_before,
  1233            "Or else negative collection!");
  1234     _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
  1235     _recent_CS_bytes_surviving->add(surviving_bytes);
  1237     // this is where we update the allocation rate of the application
  1238     double app_time_ms =
  1239       (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
  1240     if (app_time_ms < MIN_TIMER_GRANULARITY) {
  1241       // This usually happens due to the timer not having the required
  1242       // granularity. Some Linuxes are the usual culprits.
  1243       // We'll just set it to something (arbitrarily) small.
  1244       app_time_ms = 1.0;
  1246     size_t regions_allocated =
  1247       (_region_num_young - _prev_region_num_young) +
  1248       (_region_num_tenured - _prev_region_num_tenured);
  1249     double alloc_rate_ms = (double) regions_allocated / app_time_ms;
  1250     _alloc_rate_ms_seq->add(alloc_rate_ms);
  1251     _prev_region_num_young   = _region_num_young;
  1252     _prev_region_num_tenured = _region_num_tenured;
  1254     double interval_ms =
  1255       (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
  1256     update_recent_gc_times(end_time_sec, elapsed_ms);
  1257     _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
  1258     if (recent_avg_pause_time_ratio() < 0.0 ||
  1259         (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
  1260 #ifndef PRODUCT
  1261       // Dump info to allow post-facto debugging
  1262       gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
  1263       gclog_or_tty->print_cr("-------------------------------------------");
  1264       gclog_or_tty->print_cr("Recent GC Times (ms):");
  1265       _recent_gc_times_ms->dump();
  1266       gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
  1267       _recent_prev_end_times_for_all_gcs_sec->dump();
  1268       gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
  1269                              _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
  1270       // In debug mode, terminate the JVM if the user wants to debug at this point.
  1271       assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
  1272 #endif  // !PRODUCT
  1273       // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
  1274       // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
  1275       if (_recent_avg_pause_time_ratio < 0.0) {
  1276         _recent_avg_pause_time_ratio = 0.0;
  1277       } else {
  1278         assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
  1279         _recent_avg_pause_time_ratio = 1.0;
  1284   if (G1PolicyVerbose > 1) {
  1285     gclog_or_tty->print_cr("   Recording collection pause(%d)", _n_pauses);
  1288   PauseSummary* summary = _summary;
  1290   double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
  1291   double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
  1292   double update_rs_time = avg_value(_par_last_update_rs_times_ms);
  1293   double update_rs_processed_buffers =
  1294     sum_of_values(_par_last_update_rs_processed_buffers);
  1295   double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
  1296   double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
  1297   double termination_time = avg_value(_par_last_termination_times_ms);
  1299   double parallel_other_time = _cur_collection_par_time_ms -
  1300     (update_rs_time + ext_root_scan_time + mark_stack_scan_time +
  1301      scan_rs_time + obj_copy_time + termination_time);
  1302   if (update_stats) {
  1303     MainBodySummary* body_summary = summary->main_body_summary();
  1304     guarantee(body_summary != NULL, "should not be null!");
  1306     if (_satb_drain_time_set)
  1307       body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
  1308     else
  1309       body_summary->record_satb_drain_time_ms(0.0);
  1310     body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
  1311     body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
  1312     body_summary->record_update_rs_time_ms(update_rs_time);
  1313     body_summary->record_scan_rs_time_ms(scan_rs_time);
  1314     body_summary->record_obj_copy_time_ms(obj_copy_time);
  1315     if (parallel) {
  1316       body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
  1317       body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
  1318       body_summary->record_termination_time_ms(termination_time);
  1319       body_summary->record_parallel_other_time_ms(parallel_other_time);
  1321     body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
  1324   if (G1PolicyVerbose > 1) {
  1325     gclog_or_tty->print_cr("      ET: %10.6f ms           (avg: %10.6f ms)\n"
  1326                            "        CH Strong: %10.6f ms    (avg: %10.6f ms)\n"
  1327                            "        G1 Strong: %10.6f ms    (avg: %10.6f ms)\n"
  1328                            "        Evac:      %10.6f ms    (avg: %10.6f ms)\n"
  1329                            "       ET-RS:  %10.6f ms      (avg: %10.6f ms)\n"
  1330                            "      |RS|: " SIZE_FORMAT,
  1331                            elapsed_ms, recent_avg_time_for_pauses_ms(),
  1332                            _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(),
  1333                            _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(),
  1334                            evac_ms, recent_avg_time_for_evac_ms(),
  1335                            scan_rs_time,
  1336                            recent_avg_time_for_pauses_ms() -
  1337                            recent_avg_time_for_G1_strong_ms(),
  1338                            rs_size);
  1340     gclog_or_tty->print_cr("       Used at start: " SIZE_FORMAT"K"
  1341                            "       At end " SIZE_FORMAT "K\n"
  1342                            "       garbage      : " SIZE_FORMAT "K"
  1343                            "       of     " SIZE_FORMAT "K\n"
  1344                            "       survival     : %6.2f%%  (%6.2f%% avg)",
  1345                            _cur_collection_pause_used_at_start_bytes/K,
  1346                            _g1->used()/K, freed_bytes/K,
  1347                            _collection_set_bytes_used_before/K,
  1348                            survival_fraction*100.0,
  1349                            recent_avg_survival_fraction()*100.0);
  1350     gclog_or_tty->print_cr("       Recent %% gc pause time: %6.2f",
  1351                            recent_avg_pause_time_ratio() * 100.0);
  1354   double other_time_ms = elapsed_ms;
  1356   if (_satb_drain_time_set) {
  1357     other_time_ms -= _cur_satb_drain_time_ms;
  1360   if (parallel) {
  1361     other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
  1362   } else {
  1363     other_time_ms -=
  1364       update_rs_time +
  1365       ext_root_scan_time + mark_stack_scan_time +
  1366       scan_rs_time + obj_copy_time;
  1369   if (PrintGCDetails) {
  1370     gclog_or_tty->print_cr("%s, %1.8lf secs]",
  1371                            (last_pause_included_initial_mark) ? " (initial-mark)" : "",
  1372                            elapsed_ms / 1000.0);
  1374     if (_satb_drain_time_set) {
  1375       print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
  1377     if (_last_satb_drain_processed_buffers >= 0) {
  1378       print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
  1380     if (parallel) {
  1381       print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
  1382       print_par_stats(2, "GC Worker Start Time",
  1383                       _par_last_gc_worker_start_times_ms, false);
  1384       print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
  1385       print_par_sizes(3, "Processed Buffers",
  1386                       _par_last_update_rs_processed_buffers, true);
  1387       print_par_stats(2, "Ext Root Scanning",
  1388                       _par_last_ext_root_scan_times_ms);
  1389       print_par_stats(2, "Mark Stack Scanning",
  1390                       _par_last_mark_stack_scan_times_ms);
  1391       print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
  1392       print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
  1393       print_par_stats(2, "Termination", _par_last_termination_times_ms);
  1394       print_par_sizes(3, "Termination Attempts",
  1395                       _par_last_termination_attempts, true);
  1396       print_par_stats(2, "GC Worker End Time",
  1397                       _par_last_gc_worker_end_times_ms, false);
  1398       print_stats(2, "Other", parallel_other_time);
  1399       print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
  1400     } else {
  1401       print_stats(1, "Update RS", update_rs_time);
  1402       print_stats(2, "Processed Buffers",
  1403                   (int)update_rs_processed_buffers);
  1404       print_stats(1, "Ext Root Scanning", ext_root_scan_time);
  1405       print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
  1406       print_stats(1, "Scan RS", scan_rs_time);
  1407       print_stats(1, "Object Copying", obj_copy_time);
  1409 #ifndef PRODUCT
  1410     print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
  1411     print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
  1412     print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
  1413     print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
  1414     if (_num_cc_clears > 0) {
  1415       print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
  1417 #endif
  1418     print_stats(1, "Other", other_time_ms);
  1419     print_stats(2, "Choose CSet", _recorded_young_cset_choice_time_ms);
  1421     for (int i = 0; i < _aux_num; ++i) {
  1422       if (_cur_aux_times_set[i]) {
  1423         char buffer[96];
  1424         sprintf(buffer, "Aux%d", i);
  1425         print_stats(1, buffer, _cur_aux_times_ms[i]);
  1429   if (PrintGCDetails)
  1430     gclog_or_tty->print("   [");
  1431   if (PrintGC || PrintGCDetails)
  1432     _g1->print_size_transition(gclog_or_tty,
  1433                                _cur_collection_pause_used_at_start_bytes,
  1434                                _g1->used(), _g1->capacity());
  1435   if (PrintGCDetails)
  1436     gclog_or_tty->print_cr("]");
  1438   _all_pause_times_ms->add(elapsed_ms);
  1439   if (update_stats) {
  1440     summary->record_total_time_ms(elapsed_ms);
  1441     summary->record_other_time_ms(other_time_ms);
  1443   for (int i = 0; i < _aux_num; ++i)
  1444     if (_cur_aux_times_set[i])
  1445       _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
  1447   // Reset marks-between-pauses counter.
  1448   _n_marks_since_last_pause = 0;
  1450   // Update the efficiency-since-mark vars.
  1451   double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
  1452   if (elapsed_ms < MIN_TIMER_GRANULARITY) {
  1453     // This usually happens due to the timer not having the required
  1454     // granularity. Some Linuxes are the usual culprits.
  1455     // We'll just set it to something (arbitrarily) small.
  1456     proc_ms = 1.0;
  1458   double cur_efficiency = (double) freed_bytes / proc_ms;
  1460   bool new_in_marking_window = _in_marking_window;
  1461   bool new_in_marking_window_im = false;
  1462   if (during_initial_mark_pause()) {
  1463     new_in_marking_window = true;
  1464     new_in_marking_window_im = true;
  1467   if (in_young_gc_mode()) {
  1468     if (_last_full_young_gc) {
  1469       set_full_young_gcs(false);
  1470       _last_full_young_gc = false;
  1473     if ( !_last_young_gc_full ) {
  1474       if ( _should_revert_to_full_young_gcs ||
  1475            _known_garbage_ratio < 0.05 ||
  1476            (adaptive_young_list_length() &&
  1477            (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) {
  1478         set_full_young_gcs(true);
  1481     _should_revert_to_full_young_gcs = false;
  1483     if (_last_young_gc_full && !_during_marking)
  1484       _young_gc_eff_seq->add(cur_efficiency);
  1487   _short_lived_surv_rate_group->start_adding_regions();
  1488   // do that for any other surv rate groupsx
  1490   // <NEW PREDICTION>
  1492   if (update_stats) {
  1493     double pause_time_ms = elapsed_ms;
  1495     size_t diff = 0;
  1496     if (_max_pending_cards >= _pending_cards)
  1497       diff = _max_pending_cards - _pending_cards;
  1498     _pending_card_diff_seq->add((double) diff);
  1500     double cost_per_card_ms = 0.0;
  1501     if (_pending_cards > 0) {
  1502       cost_per_card_ms = update_rs_time / (double) _pending_cards;
  1503       _cost_per_card_ms_seq->add(cost_per_card_ms);
  1506     size_t cards_scanned = _g1->cards_scanned();
  1508     double cost_per_entry_ms = 0.0;
  1509     if (cards_scanned > 10) {
  1510       cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
  1511       if (_last_young_gc_full)
  1512         _cost_per_entry_ms_seq->add(cost_per_entry_ms);
  1513       else
  1514         _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
  1517     if (_max_rs_lengths > 0) {
  1518       double cards_per_entry_ratio =
  1519         (double) cards_scanned / (double) _max_rs_lengths;
  1520       if (_last_young_gc_full)
  1521         _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
  1522       else
  1523         _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
  1526     size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
  1527     if (rs_length_diff >= 0)
  1528       _rs_length_diff_seq->add((double) rs_length_diff);
  1530     size_t copied_bytes = surviving_bytes;
  1531     double cost_per_byte_ms = 0.0;
  1532     if (copied_bytes > 0) {
  1533       cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
  1534       if (_in_marking_window)
  1535         _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
  1536       else
  1537         _cost_per_byte_ms_seq->add(cost_per_byte_ms);
  1540     double all_other_time_ms = pause_time_ms -
  1541       (update_rs_time + scan_rs_time + obj_copy_time +
  1542        _mark_closure_time_ms + termination_time);
  1544     double young_other_time_ms = 0.0;
  1545     if (_recorded_young_regions > 0) {
  1546       young_other_time_ms =
  1547         _recorded_young_cset_choice_time_ms +
  1548         _recorded_young_free_cset_time_ms;
  1549       _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
  1550                                              (double) _recorded_young_regions);
  1552     double non_young_other_time_ms = 0.0;
  1553     if (_recorded_non_young_regions > 0) {
  1554       non_young_other_time_ms =
  1555         _recorded_non_young_cset_choice_time_ms +
  1556         _recorded_non_young_free_cset_time_ms;
  1558       _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
  1559                                          (double) _recorded_non_young_regions);
  1562     double constant_other_time_ms = all_other_time_ms -
  1563       (young_other_time_ms + non_young_other_time_ms);
  1564     _constant_other_time_ms_seq->add(constant_other_time_ms);
  1566     double survival_ratio = 0.0;
  1567     if (_bytes_in_collection_set_before_gc > 0) {
  1568       survival_ratio = (double) bytes_in_to_space_during_gc() /
  1569         (double) _bytes_in_collection_set_before_gc;
  1572     _pending_cards_seq->add((double) _pending_cards);
  1573     _scanned_cards_seq->add((double) cards_scanned);
  1574     _rs_lengths_seq->add((double) _max_rs_lengths);
  1576     double expensive_region_limit_ms =
  1577       (double) MaxGCPauseMillis - predict_constant_other_time_ms();
  1578     if (expensive_region_limit_ms < 0.0) {
  1579       // this means that the other time was predicted to be longer than
  1580       // than the max pause time
  1581       expensive_region_limit_ms = (double) MaxGCPauseMillis;
  1583     _expensive_region_limit_ms = expensive_region_limit_ms;
  1585     if (PREDICTIONS_VERBOSE) {
  1586       gclog_or_tty->print_cr("");
  1587       gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
  1588                     "REGIONS %d %d %d "
  1589                     "PENDING_CARDS %d %d "
  1590                     "CARDS_SCANNED %d %d "
  1591                     "RS_LENGTHS %d %d "
  1592                     "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
  1593                     "SURVIVAL_RATIO %1.6lf %1.6lf "
  1594                     "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
  1595                     "OTHER_YOUNG %1.6lf %1.6lf "
  1596                     "OTHER_NON_YOUNG %1.6lf %1.6lf "
  1597                     "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
  1598                     "ELAPSED %1.6lf %1.6lf ",
  1599                     _cur_collection_start_sec,
  1600                     (!_last_young_gc_full) ? 2 :
  1601                     (last_pause_included_initial_mark) ? 1 : 0,
  1602                     _recorded_region_num,
  1603                     _recorded_young_regions,
  1604                     _recorded_non_young_regions,
  1605                     _predicted_pending_cards, _pending_cards,
  1606                     _predicted_cards_scanned, cards_scanned,
  1607                     _predicted_rs_lengths, _max_rs_lengths,
  1608                     _predicted_rs_update_time_ms, update_rs_time,
  1609                     _predicted_rs_scan_time_ms, scan_rs_time,
  1610                     _predicted_survival_ratio, survival_ratio,
  1611                     _predicted_object_copy_time_ms, obj_copy_time,
  1612                     _predicted_constant_other_time_ms, constant_other_time_ms,
  1613                     _predicted_young_other_time_ms, young_other_time_ms,
  1614                     _predicted_non_young_other_time_ms,
  1615                     non_young_other_time_ms,
  1616                     _vtime_diff_ms, termination_time,
  1617                     _predicted_pause_time_ms, elapsed_ms);
  1620     if (G1PolicyVerbose > 0) {
  1621       gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
  1622                     _predicted_pause_time_ms,
  1623                     (_within_target) ? "within" : "outside",
  1624                     elapsed_ms);
  1629   _in_marking_window = new_in_marking_window;
  1630   _in_marking_window_im = new_in_marking_window_im;
  1631   _free_regions_at_end_of_collection = _g1->free_regions();
  1632   calculate_young_list_min_length();
  1633   calculate_young_list_target_length();
  1635   // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
  1636   double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
  1637   adjust_concurrent_refinement(update_rs_time, update_rs_processed_buffers, update_rs_time_goal_ms);
  1638   // </NEW PREDICTION>
  1641 // <NEW PREDICTION>
  1643 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
  1644                                                      double update_rs_processed_buffers,
  1645                                                      double goal_ms) {
  1646   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
  1647   ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
  1649   if (G1UseAdaptiveConcRefinement) {
  1650     const int k_gy = 3, k_gr = 6;
  1651     const double inc_k = 1.1, dec_k = 0.9;
  1653     int g = cg1r->green_zone();
  1654     if (update_rs_time > goal_ms) {
  1655       g = (int)(g * dec_k);  // Can become 0, that's OK. That would mean a mutator-only processing.
  1656     } else {
  1657       if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
  1658         g = (int)MAX2(g * inc_k, g + 1.0);
  1661     // Change the refinement threads params
  1662     cg1r->set_green_zone(g);
  1663     cg1r->set_yellow_zone(g * k_gy);
  1664     cg1r->set_red_zone(g * k_gr);
  1665     cg1r->reinitialize_threads();
  1667     int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
  1668     int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
  1669                                     cg1r->yellow_zone());
  1670     // Change the barrier params
  1671     dcqs.set_process_completed_threshold(processing_threshold);
  1672     dcqs.set_max_completed_queue(cg1r->red_zone());
  1675   int curr_queue_size = dcqs.completed_buffers_num();
  1676   if (curr_queue_size >= cg1r->yellow_zone()) {
  1677     dcqs.set_completed_queue_padding(curr_queue_size);
  1678   } else {
  1679     dcqs.set_completed_queue_padding(0);
  1681   dcqs.notify_if_necessary();
  1684 double
  1685 G1CollectorPolicy::
  1686 predict_young_collection_elapsed_time_ms(size_t adjustment) {
  1687   guarantee( adjustment == 0 || adjustment == 1, "invariant" );
  1689   G1CollectedHeap* g1h = G1CollectedHeap::heap();
  1690   size_t young_num = g1h->young_list()->length();
  1691   if (young_num == 0)
  1692     return 0.0;
  1694   young_num += adjustment;
  1695   size_t pending_cards = predict_pending_cards();
  1696   size_t rs_lengths = g1h->young_list()->sampled_rs_lengths() +
  1697                       predict_rs_length_diff();
  1698   size_t card_num;
  1699   if (full_young_gcs())
  1700     card_num = predict_young_card_num(rs_lengths);
  1701   else
  1702     card_num = predict_non_young_card_num(rs_lengths);
  1703   size_t young_byte_size = young_num * HeapRegion::GrainBytes;
  1704   double accum_yg_surv_rate =
  1705     _short_lived_surv_rate_group->accum_surv_rate(adjustment);
  1707   size_t bytes_to_copy =
  1708     (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
  1710   return
  1711     predict_rs_update_time_ms(pending_cards) +
  1712     predict_rs_scan_time_ms(card_num) +
  1713     predict_object_copy_time_ms(bytes_to_copy) +
  1714     predict_young_other_time_ms(young_num) +
  1715     predict_constant_other_time_ms();
  1718 double
  1719 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
  1720   size_t rs_length = predict_rs_length_diff();
  1721   size_t card_num;
  1722   if (full_young_gcs())
  1723     card_num = predict_young_card_num(rs_length);
  1724   else
  1725     card_num = predict_non_young_card_num(rs_length);
  1726   return predict_base_elapsed_time_ms(pending_cards, card_num);
  1729 double
  1730 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
  1731                                                 size_t scanned_cards) {
  1732   return
  1733     predict_rs_update_time_ms(pending_cards) +
  1734     predict_rs_scan_time_ms(scanned_cards) +
  1735     predict_constant_other_time_ms();
  1738 double
  1739 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
  1740                                                   bool young) {
  1741   size_t rs_length = hr->rem_set()->occupied();
  1742   size_t card_num;
  1743   if (full_young_gcs())
  1744     card_num = predict_young_card_num(rs_length);
  1745   else
  1746     card_num = predict_non_young_card_num(rs_length);
  1747   size_t bytes_to_copy = predict_bytes_to_copy(hr);
  1749   double region_elapsed_time_ms =
  1750     predict_rs_scan_time_ms(card_num) +
  1751     predict_object_copy_time_ms(bytes_to_copy);
  1753   if (young)
  1754     region_elapsed_time_ms += predict_young_other_time_ms(1);
  1755   else
  1756     region_elapsed_time_ms += predict_non_young_other_time_ms(1);
  1758   return region_elapsed_time_ms;
  1761 size_t
  1762 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
  1763   size_t bytes_to_copy;
  1764   if (hr->is_marked())
  1765     bytes_to_copy = hr->max_live_bytes();
  1766   else {
  1767     guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
  1768                "invariant" );
  1769     int age = hr->age_in_surv_rate_group();
  1770     double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
  1771     bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
  1774   return bytes_to_copy;
  1777 void
  1778 G1CollectorPolicy::start_recording_regions() {
  1779   _recorded_rs_lengths            = 0;
  1780   _recorded_young_regions         = 0;
  1781   _recorded_non_young_regions     = 0;
  1783 #if PREDICTIONS_VERBOSE
  1784   _recorded_marked_bytes          = 0;
  1785   _recorded_young_bytes           = 0;
  1786   _predicted_bytes_to_copy        = 0;
  1787   _predicted_rs_lengths           = 0;
  1788   _predicted_cards_scanned        = 0;
  1789 #endif // PREDICTIONS_VERBOSE
  1792 void
  1793 G1CollectorPolicy::record_cset_region_info(HeapRegion* hr, bool young) {
  1794 #if PREDICTIONS_VERBOSE
  1795   if (!young) {
  1796     _recorded_marked_bytes += hr->max_live_bytes();
  1798   _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
  1799 #endif // PREDICTIONS_VERBOSE
  1801   size_t rs_length = hr->rem_set()->occupied();
  1802   _recorded_rs_lengths += rs_length;
  1805 void
  1806 G1CollectorPolicy::record_non_young_cset_region(HeapRegion* hr) {
  1807   assert(!hr->is_young(), "should not call this");
  1808   ++_recorded_non_young_regions;
  1809   record_cset_region_info(hr, false);
  1812 void
  1813 G1CollectorPolicy::set_recorded_young_regions(size_t n_regions) {
  1814   _recorded_young_regions = n_regions;
  1817 void G1CollectorPolicy::set_recorded_young_bytes(size_t bytes) {
  1818 #if PREDICTIONS_VERBOSE
  1819   _recorded_young_bytes = bytes;
  1820 #endif // PREDICTIONS_VERBOSE
  1823 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
  1824   _recorded_rs_lengths = rs_lengths;
  1827 void G1CollectorPolicy::set_predicted_bytes_to_copy(size_t bytes) {
  1828   _predicted_bytes_to_copy = bytes;
  1831 void
  1832 G1CollectorPolicy::end_recording_regions() {
  1833   // The _predicted_pause_time_ms field is referenced in code
  1834   // not under PREDICTIONS_VERBOSE. Let's initialize it.
  1835   _predicted_pause_time_ms = -1.0;
  1837 #if PREDICTIONS_VERBOSE
  1838   _predicted_pending_cards = predict_pending_cards();
  1839   _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
  1840   if (full_young_gcs())
  1841     _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
  1842   else
  1843     _predicted_cards_scanned +=
  1844       predict_non_young_card_num(_predicted_rs_lengths);
  1845   _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
  1847   _predicted_rs_update_time_ms =
  1848     predict_rs_update_time_ms(_g1->pending_card_num());
  1849   _predicted_rs_scan_time_ms =
  1850     predict_rs_scan_time_ms(_predicted_cards_scanned);
  1851   _predicted_object_copy_time_ms =
  1852     predict_object_copy_time_ms(_predicted_bytes_to_copy);
  1853   _predicted_constant_other_time_ms =
  1854     predict_constant_other_time_ms();
  1855   _predicted_young_other_time_ms =
  1856     predict_young_other_time_ms(_recorded_young_regions);
  1857   _predicted_non_young_other_time_ms =
  1858     predict_non_young_other_time_ms(_recorded_non_young_regions);
  1860   _predicted_pause_time_ms =
  1861     _predicted_rs_update_time_ms +
  1862     _predicted_rs_scan_time_ms +
  1863     _predicted_object_copy_time_ms +
  1864     _predicted_constant_other_time_ms +
  1865     _predicted_young_other_time_ms +
  1866     _predicted_non_young_other_time_ms;
  1867 #endif // PREDICTIONS_VERBOSE
  1870 void G1CollectorPolicy::check_if_region_is_too_expensive(double
  1871                                                            predicted_time_ms) {
  1872   // I don't think we need to do this when in young GC mode since
  1873   // marking will be initiated next time we hit the soft limit anyway...
  1874   if (predicted_time_ms > _expensive_region_limit_ms) {
  1875     if (!in_young_gc_mode()) {
  1876         set_full_young_gcs(true);
  1877         // We might want to do something different here. However,
  1878         // right now we don't support the non-generational G1 mode
  1879         // (and in fact we are planning to remove the associated code,
  1880         // see CR 6814390). So, let's leave it as is and this will be
  1881         // removed some time in the future
  1882         ShouldNotReachHere();
  1883         set_during_initial_mark_pause();
  1884     } else
  1885       // no point in doing another partial one
  1886       _should_revert_to_full_young_gcs = true;
  1890 // </NEW PREDICTION>
  1893 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
  1894                                                double elapsed_ms) {
  1895   _recent_gc_times_ms->add(elapsed_ms);
  1896   _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
  1897   _prev_collection_pause_end_ms = end_time_sec * 1000.0;
  1900 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
  1901   if (_recent_pause_times_ms->num() == 0) return (double) MaxGCPauseMillis;
  1902   else return _recent_pause_times_ms->avg();
  1905 double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() {
  1906   if (_recent_CH_strong_roots_times_ms->num() == 0)
  1907     return (double)MaxGCPauseMillis/3.0;
  1908   else return _recent_CH_strong_roots_times_ms->avg();
  1911 double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() {
  1912   if (_recent_G1_strong_roots_times_ms->num() == 0)
  1913     return (double)MaxGCPauseMillis/3.0;
  1914   else return _recent_G1_strong_roots_times_ms->avg();
  1917 double G1CollectorPolicy::recent_avg_time_for_evac_ms() {
  1918   if (_recent_evac_times_ms->num() == 0) return (double)MaxGCPauseMillis/3.0;
  1919   else return _recent_evac_times_ms->avg();
  1922 int G1CollectorPolicy::number_of_recent_gcs() {
  1923   assert(_recent_CH_strong_roots_times_ms->num() ==
  1924          _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync");
  1925   assert(_recent_G1_strong_roots_times_ms->num() ==
  1926          _recent_evac_times_ms->num(), "Sequence out of sync");
  1927   assert(_recent_evac_times_ms->num() ==
  1928          _recent_pause_times_ms->num(), "Sequence out of sync");
  1929   assert(_recent_pause_times_ms->num() ==
  1930          _recent_CS_bytes_used_before->num(), "Sequence out of sync");
  1931   assert(_recent_CS_bytes_used_before->num() ==
  1932          _recent_CS_bytes_surviving->num(), "Sequence out of sync");
  1933   return _recent_pause_times_ms->num();
  1936 double G1CollectorPolicy::recent_avg_survival_fraction() {
  1937   return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
  1938                                            _recent_CS_bytes_used_before);
  1941 double G1CollectorPolicy::last_survival_fraction() {
  1942   return last_survival_fraction_work(_recent_CS_bytes_surviving,
  1943                                      _recent_CS_bytes_used_before);
  1946 double
  1947 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
  1948                                                      TruncatedSeq* before) {
  1949   assert(surviving->num() == before->num(), "Sequence out of sync");
  1950   if (before->sum() > 0.0) {
  1951       double recent_survival_rate = surviving->sum() / before->sum();
  1952       // We exempt parallel collection from this check because Alloc Buffer
  1953       // fragmentation can produce negative collections.
  1954       // Further, we're now always doing parallel collection.  But I'm still
  1955       // leaving this here as a placeholder for a more precise assertion later.
  1956       // (DLD, 10/05.)
  1957       assert((true || G1CollectedHeap::use_parallel_gc_threads()) ||
  1958              _g1->evacuation_failed() ||
  1959              recent_survival_rate <= 1.0, "Or bad frac");
  1960       return recent_survival_rate;
  1961   } else {
  1962     return 1.0; // Be conservative.
  1966 double
  1967 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
  1968                                                TruncatedSeq* before) {
  1969   assert(surviving->num() == before->num(), "Sequence out of sync");
  1970   if (surviving->num() > 0 && before->last() > 0.0) {
  1971     double last_survival_rate = surviving->last() / before->last();
  1972     // We exempt parallel collection from this check because Alloc Buffer
  1973     // fragmentation can produce negative collections.
  1974     // Further, we're now always doing parallel collection.  But I'm still
  1975     // leaving this here as a placeholder for a more precise assertion later.
  1976     // (DLD, 10/05.)
  1977     assert((true || G1CollectedHeap::use_parallel_gc_threads()) ||
  1978            last_survival_rate <= 1.0, "Or bad frac");
  1979     return last_survival_rate;
  1980   } else {
  1981     return 1.0;
  1985 static const int survival_min_obs = 5;
  1986 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
  1987 static const double min_survival_rate = 0.1;
  1989 double
  1990 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
  1991                                                            double latest) {
  1992   double res = avg;
  1993   if (number_of_recent_gcs() < survival_min_obs) {
  1994     res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
  1996   res = MAX2(res, latest);
  1997   res = MAX2(res, min_survival_rate);
  1998   // In the parallel case, LAB fragmentation can produce "negative
  1999   // collections"; so can evac failure.  Cap at 1.0
  2000   res = MIN2(res, 1.0);
  2001   return res;
  2004 size_t G1CollectorPolicy::expansion_amount() {
  2005   if ((recent_avg_pause_time_ratio() * 100.0) > _gc_overhead_perc) {
  2006     // We will double the existing space, or take
  2007     // G1ExpandByPercentOfAvailable % of the available expansion
  2008     // space, whichever is smaller, bounded below by a minimum
  2009     // expansion (unless that's all that's left.)
  2010     const size_t min_expand_bytes = 1*M;
  2011     size_t reserved_bytes = _g1->g1_reserved_obj_bytes();
  2012     size_t committed_bytes = _g1->capacity();
  2013     size_t uncommitted_bytes = reserved_bytes - committed_bytes;
  2014     size_t expand_bytes;
  2015     size_t expand_bytes_via_pct =
  2016       uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
  2017     expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
  2018     expand_bytes = MAX2(expand_bytes, min_expand_bytes);
  2019     expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
  2020     if (G1PolicyVerbose > 1) {
  2021       gclog_or_tty->print("Decided to expand: ratio = %5.2f, "
  2022                  "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n"
  2023                  "                   Answer = %d.\n",
  2024                  recent_avg_pause_time_ratio(),
  2025                  byte_size_in_proper_unit(committed_bytes),
  2026                  proper_unit_for_byte_size(committed_bytes),
  2027                  byte_size_in_proper_unit(uncommitted_bytes),
  2028                  proper_unit_for_byte_size(uncommitted_bytes),
  2029                  byte_size_in_proper_unit(expand_bytes_via_pct),
  2030                  proper_unit_for_byte_size(expand_bytes_via_pct),
  2031                  byte_size_in_proper_unit(expand_bytes),
  2032                  proper_unit_for_byte_size(expand_bytes));
  2034     return expand_bytes;
  2035   } else {
  2036     return 0;
  2040 void G1CollectorPolicy::note_start_of_mark_thread() {
  2041   _mark_thread_startup_sec = os::elapsedTime();
  2044 class CountCSClosure: public HeapRegionClosure {
  2045   G1CollectorPolicy* _g1_policy;
  2046 public:
  2047   CountCSClosure(G1CollectorPolicy* g1_policy) :
  2048     _g1_policy(g1_policy) {}
  2049   bool doHeapRegion(HeapRegion* r) {
  2050     _g1_policy->_bytes_in_collection_set_before_gc += r->used();
  2051     return false;
  2053 };
  2055 void G1CollectorPolicy::count_CS_bytes_used() {
  2056   CountCSClosure cs_closure(this);
  2057   _g1->collection_set_iterate(&cs_closure);
  2060 static void print_indent(int level) {
  2061   for (int j = 0; j < level+1; ++j)
  2062     gclog_or_tty->print("   ");
  2065 void G1CollectorPolicy::print_summary (int level,
  2066                                        const char* str,
  2067                                        NumberSeq* seq) const {
  2068   double sum = seq->sum();
  2069   print_indent(level);
  2070   gclog_or_tty->print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
  2071                 str, sum / 1000.0, seq->avg());
  2074 void G1CollectorPolicy::print_summary_sd (int level,
  2075                                           const char* str,
  2076                                           NumberSeq* seq) const {
  2077   print_summary(level, str, seq);
  2078   print_indent(level + 5);
  2079   gclog_or_tty->print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
  2080                 seq->num(), seq->sd(), seq->maximum());
  2083 void G1CollectorPolicy::check_other_times(int level,
  2084                                         NumberSeq* other_times_ms,
  2085                                         NumberSeq* calc_other_times_ms) const {
  2086   bool should_print = false;
  2088   double max_sum = MAX2(fabs(other_times_ms->sum()),
  2089                         fabs(calc_other_times_ms->sum()));
  2090   double min_sum = MIN2(fabs(other_times_ms->sum()),
  2091                         fabs(calc_other_times_ms->sum()));
  2092   double sum_ratio = max_sum / min_sum;
  2093   if (sum_ratio > 1.1) {
  2094     should_print = true;
  2095     print_indent(level + 1);
  2096     gclog_or_tty->print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
  2099   double max_avg = MAX2(fabs(other_times_ms->avg()),
  2100                         fabs(calc_other_times_ms->avg()));
  2101   double min_avg = MIN2(fabs(other_times_ms->avg()),
  2102                         fabs(calc_other_times_ms->avg()));
  2103   double avg_ratio = max_avg / min_avg;
  2104   if (avg_ratio > 1.1) {
  2105     should_print = true;
  2106     print_indent(level + 1);
  2107     gclog_or_tty->print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
  2110   if (other_times_ms->sum() < -0.01) {
  2111     print_indent(level + 1);
  2112     gclog_or_tty->print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
  2115   if (other_times_ms->avg() < -0.01) {
  2116     print_indent(level + 1);
  2117     gclog_or_tty->print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
  2120   if (calc_other_times_ms->sum() < -0.01) {
  2121     should_print = true;
  2122     print_indent(level + 1);
  2123     gclog_or_tty->print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
  2126   if (calc_other_times_ms->avg() < -0.01) {
  2127     should_print = true;
  2128     print_indent(level + 1);
  2129     gclog_or_tty->print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
  2132   if (should_print)
  2133     print_summary(level, "Other(Calc)", calc_other_times_ms);
  2136 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
  2137   bool parallel = G1CollectedHeap::use_parallel_gc_threads();
  2138   MainBodySummary*    body_summary = summary->main_body_summary();
  2139   if (summary->get_total_seq()->num() > 0) {
  2140     print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
  2141     if (body_summary != NULL) {
  2142       print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
  2143       if (parallel) {
  2144         print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
  2145         print_summary(2, "Update RS", body_summary->get_update_rs_seq());
  2146         print_summary(2, "Ext Root Scanning",
  2147                       body_summary->get_ext_root_scan_seq());
  2148         print_summary(2, "Mark Stack Scanning",
  2149                       body_summary->get_mark_stack_scan_seq());
  2150         print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
  2151         print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
  2152         print_summary(2, "Termination", body_summary->get_termination_seq());
  2153         print_summary(2, "Other", body_summary->get_parallel_other_seq());
  2155           NumberSeq* other_parts[] = {
  2156             body_summary->get_update_rs_seq(),
  2157             body_summary->get_ext_root_scan_seq(),
  2158             body_summary->get_mark_stack_scan_seq(),
  2159             body_summary->get_scan_rs_seq(),
  2160             body_summary->get_obj_copy_seq(),
  2161             body_summary->get_termination_seq()
  2162           };
  2163           NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
  2164                                         6, other_parts);
  2165           check_other_times(2, body_summary->get_parallel_other_seq(),
  2166                             &calc_other_times_ms);
  2168         print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
  2169         print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
  2170       } else {
  2171         print_summary(1, "Update RS", body_summary->get_update_rs_seq());
  2172         print_summary(1, "Ext Root Scanning",
  2173                       body_summary->get_ext_root_scan_seq());
  2174         print_summary(1, "Mark Stack Scanning",
  2175                       body_summary->get_mark_stack_scan_seq());
  2176         print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
  2177         print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
  2180     print_summary(1, "Other", summary->get_other_seq());
  2182       if (body_summary != NULL) {
  2183         NumberSeq calc_other_times_ms;
  2184         if (parallel) {
  2185           // parallel
  2186           NumberSeq* other_parts[] = {
  2187             body_summary->get_satb_drain_seq(),
  2188             body_summary->get_parallel_seq(),
  2189             body_summary->get_clear_ct_seq()
  2190           };
  2191           calc_other_times_ms = NumberSeq(summary->get_total_seq(),
  2192                                                 3, other_parts);
  2193         } else {
  2194           // serial
  2195           NumberSeq* other_parts[] = {
  2196             body_summary->get_satb_drain_seq(),
  2197             body_summary->get_update_rs_seq(),
  2198             body_summary->get_ext_root_scan_seq(),
  2199             body_summary->get_mark_stack_scan_seq(),
  2200             body_summary->get_scan_rs_seq(),
  2201             body_summary->get_obj_copy_seq()
  2202           };
  2203           calc_other_times_ms = NumberSeq(summary->get_total_seq(),
  2204                                                 6, other_parts);
  2206         check_other_times(1,  summary->get_other_seq(), &calc_other_times_ms);
  2209   } else {
  2210     print_indent(0);
  2211     gclog_or_tty->print_cr("none");
  2213   gclog_or_tty->print_cr("");
  2216 void G1CollectorPolicy::print_tracing_info() const {
  2217   if (TraceGen0Time) {
  2218     gclog_or_tty->print_cr("ALL PAUSES");
  2219     print_summary_sd(0, "Total", _all_pause_times_ms);
  2220     gclog_or_tty->print_cr("");
  2221     gclog_or_tty->print_cr("");
  2222     gclog_or_tty->print_cr("   Full Young GC Pauses:    %8d", _full_young_pause_num);
  2223     gclog_or_tty->print_cr("   Partial Young GC Pauses: %8d", _partial_young_pause_num);
  2224     gclog_or_tty->print_cr("");
  2226     gclog_or_tty->print_cr("EVACUATION PAUSES");
  2227     print_summary(_summary);
  2229     gclog_or_tty->print_cr("MISC");
  2230     print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
  2231     print_summary_sd(0, "Yields", _all_yield_times_ms);
  2232     for (int i = 0; i < _aux_num; ++i) {
  2233       if (_all_aux_times_ms[i].num() > 0) {
  2234         char buffer[96];
  2235         sprintf(buffer, "Aux%d", i);
  2236         print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
  2240     size_t all_region_num = _region_num_young + _region_num_tenured;
  2241     gclog_or_tty->print_cr("   New Regions %8d, Young %8d (%6.2lf%%), "
  2242                "Tenured %8d (%6.2lf%%)",
  2243                all_region_num,
  2244                _region_num_young,
  2245                (double) _region_num_young / (double) all_region_num * 100.0,
  2246                _region_num_tenured,
  2247                (double) _region_num_tenured / (double) all_region_num * 100.0);
  2249   if (TraceGen1Time) {
  2250     if (_all_full_gc_times_ms->num() > 0) {
  2251       gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
  2252                  _all_full_gc_times_ms->num(),
  2253                  _all_full_gc_times_ms->sum() / 1000.0);
  2254       gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
  2255       gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
  2256                     _all_full_gc_times_ms->sd(),
  2257                     _all_full_gc_times_ms->maximum());
  2262 void G1CollectorPolicy::print_yg_surv_rate_info() const {
  2263 #ifndef PRODUCT
  2264   _short_lived_surv_rate_group->print_surv_rate_summary();
  2265   // add this call for any other surv rate groups
  2266 #endif // PRODUCT
  2269 bool
  2270 G1CollectorPolicy::should_add_next_region_to_young_list() {
  2271   assert(in_young_gc_mode(), "should be in young GC mode");
  2272   bool ret;
  2273   size_t young_list_length = _g1->young_list()->length();
  2274   size_t young_list_max_length = _young_list_target_length;
  2275   if (G1FixedEdenSize) {
  2276     young_list_max_length -= _max_survivor_regions;
  2278   if (young_list_length < young_list_max_length) {
  2279     ret = true;
  2280     ++_region_num_young;
  2281   } else {
  2282     ret = false;
  2283     ++_region_num_tenured;
  2286   return ret;
  2289 #ifndef PRODUCT
  2290 // for debugging, bit of a hack...
  2291 static char*
  2292 region_num_to_mbs(int length) {
  2293   static char buffer[64];
  2294   double bytes = (double) (length * HeapRegion::GrainBytes);
  2295   double mbs = bytes / (double) (1024 * 1024);
  2296   sprintf(buffer, "%7.2lfMB", mbs);
  2297   return buffer;
  2299 #endif // PRODUCT
  2301 size_t G1CollectorPolicy::max_regions(int purpose) {
  2302   switch (purpose) {
  2303     case GCAllocForSurvived:
  2304       return _max_survivor_regions;
  2305     case GCAllocForTenured:
  2306       return REGIONS_UNLIMITED;
  2307     default:
  2308       ShouldNotReachHere();
  2309       return REGIONS_UNLIMITED;
  2310   };
  2313 // Calculates survivor space parameters.
  2314 void G1CollectorPolicy::calculate_survivors_policy()
  2316   if (G1FixedSurvivorSpaceSize == 0) {
  2317     _max_survivor_regions = _young_list_target_length / SurvivorRatio;
  2318   } else {
  2319     _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
  2322   if (G1FixedTenuringThreshold) {
  2323     _tenuring_threshold = MaxTenuringThreshold;
  2324   } else {
  2325     _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
  2326         HeapRegion::GrainWords * _max_survivor_regions);
  2330 bool
  2331 G1CollectorPolicy_BestRegionsFirst::should_do_collection_pause(size_t
  2332                                                                word_size) {
  2333   assert(_g1->regions_accounted_for(), "Region leakage!");
  2334   double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
  2336   size_t young_list_length = _g1->young_list()->length();
  2337   size_t young_list_max_length = _young_list_target_length;
  2338   if (G1FixedEdenSize) {
  2339     young_list_max_length -= _max_survivor_regions;
  2341   bool reached_target_length = young_list_length >= young_list_max_length;
  2343   if (in_young_gc_mode()) {
  2344     if (reached_target_length) {
  2345       assert( young_list_length > 0 && _g1->young_list()->length() > 0,
  2346               "invariant" );
  2347       return true;
  2349   } else {
  2350     guarantee( false, "should not reach here" );
  2353   return false;
  2356 #ifndef PRODUCT
  2357 class HRSortIndexIsOKClosure: public HeapRegionClosure {
  2358   CollectionSetChooser* _chooser;
  2359 public:
  2360   HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
  2361     _chooser(chooser) {}
  2363   bool doHeapRegion(HeapRegion* r) {
  2364     if (!r->continuesHumongous()) {
  2365       assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
  2367     return false;
  2369 };
  2371 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
  2372   HRSortIndexIsOKClosure cl(_collectionSetChooser);
  2373   _g1->heap_region_iterate(&cl);
  2374   return true;
  2376 #endif
  2378 bool
  2379 G1CollectorPolicy::force_initial_mark_if_outside_cycle() {
  2380   bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
  2381   if (!during_cycle) {
  2382     set_initiate_conc_mark_if_possible();
  2383     return true;
  2384   } else {
  2385     return false;
  2389 void
  2390 G1CollectorPolicy::decide_on_conc_mark_initiation() {
  2391   // We are about to decide on whether this pause will be an
  2392   // initial-mark pause.
  2394   // First, during_initial_mark_pause() should not be already set. We
  2395   // will set it here if we have to. However, it should be cleared by
  2396   // the end of the pause (it's only set for the duration of an
  2397   // initial-mark pause).
  2398   assert(!during_initial_mark_pause(), "pre-condition");
  2400   if (initiate_conc_mark_if_possible()) {
  2401     // We had noticed on a previous pause that the heap occupancy has
  2402     // gone over the initiating threshold and we should start a
  2403     // concurrent marking cycle. So we might initiate one.
  2405     bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
  2406     if (!during_cycle) {
  2407       // The concurrent marking thread is not "during a cycle", i.e.,
  2408       // it has completed the last one. So we can go ahead and
  2409       // initiate a new cycle.
  2411       set_during_initial_mark_pause();
  2413       // And we can now clear initiate_conc_mark_if_possible() as
  2414       // we've already acted on it.
  2415       clear_initiate_conc_mark_if_possible();
  2416     } else {
  2417       // The concurrent marking thread is still finishing up the
  2418       // previous cycle. If we start one right now the two cycles
  2419       // overlap. In particular, the concurrent marking thread might
  2420       // be in the process of clearing the next marking bitmap (which
  2421       // we will use for the next cycle if we start one). Starting a
  2422       // cycle now will be bad given that parts of the marking
  2423       // information might get cleared by the marking thread. And we
  2424       // cannot wait for the marking thread to finish the cycle as it
  2425       // periodically yields while clearing the next marking bitmap
  2426       // and, if it's in a yield point, it's waiting for us to
  2427       // finish. So, at this point we will not start a cycle and we'll
  2428       // let the concurrent marking thread complete the last one.
  2433 void
  2434 G1CollectorPolicy_BestRegionsFirst::
  2435 record_collection_pause_start(double start_time_sec, size_t start_used) {
  2436   G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
  2439 class NextNonCSElemFinder: public HeapRegionClosure {
  2440   HeapRegion* _res;
  2441 public:
  2442   NextNonCSElemFinder(): _res(NULL) {}
  2443   bool doHeapRegion(HeapRegion* r) {
  2444     if (!r->in_collection_set()) {
  2445       _res = r;
  2446       return true;
  2447     } else {
  2448       return false;
  2451   HeapRegion* res() { return _res; }
  2452 };
  2454 class KnownGarbageClosure: public HeapRegionClosure {
  2455   CollectionSetChooser* _hrSorted;
  2457 public:
  2458   KnownGarbageClosure(CollectionSetChooser* hrSorted) :
  2459     _hrSorted(hrSorted)
  2460   {}
  2462   bool doHeapRegion(HeapRegion* r) {
  2463     // We only include humongous regions in collection
  2464     // sets when concurrent mark shows that their contained object is
  2465     // unreachable.
  2467     // Do we have any marking information for this region?
  2468     if (r->is_marked()) {
  2469       // We don't include humongous regions in collection
  2470       // sets because we collect them immediately at the end of a marking
  2471       // cycle.  We also don't include young regions because we *must*
  2472       // include them in the next collection pause.
  2473       if (!r->isHumongous() && !r->is_young()) {
  2474         _hrSorted->addMarkedHeapRegion(r);
  2477     return false;
  2479 };
  2481 class ParKnownGarbageHRClosure: public HeapRegionClosure {
  2482   CollectionSetChooser* _hrSorted;
  2483   jint _marked_regions_added;
  2484   jint _chunk_size;
  2485   jint _cur_chunk_idx;
  2486   jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
  2487   int _worker;
  2488   int _invokes;
  2490   void get_new_chunk() {
  2491     _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
  2492     _cur_chunk_end = _cur_chunk_idx + _chunk_size;
  2494   void add_region(HeapRegion* r) {
  2495     if (_cur_chunk_idx == _cur_chunk_end) {
  2496       get_new_chunk();
  2498     assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
  2499     _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
  2500     _marked_regions_added++;
  2501     _cur_chunk_idx++;
  2504 public:
  2505   ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
  2506                            jint chunk_size,
  2507                            int worker) :
  2508     _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
  2509     _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
  2510     _invokes(0)
  2511   {}
  2513   bool doHeapRegion(HeapRegion* r) {
  2514     // We only include humongous regions in collection
  2515     // sets when concurrent mark shows that their contained object is
  2516     // unreachable.
  2517     _invokes++;
  2519     // Do we have any marking information for this region?
  2520     if (r->is_marked()) {
  2521       // We don't include humongous regions in collection
  2522       // sets because we collect them immediately at the end of a marking
  2523       // cycle.
  2524       // We also do not include young regions in collection sets
  2525       if (!r->isHumongous() && !r->is_young()) {
  2526         add_region(r);
  2529     return false;
  2531   jint marked_regions_added() { return _marked_regions_added; }
  2532   int invokes() { return _invokes; }
  2533 };
  2535 class ParKnownGarbageTask: public AbstractGangTask {
  2536   CollectionSetChooser* _hrSorted;
  2537   jint _chunk_size;
  2538   G1CollectedHeap* _g1;
  2539 public:
  2540   ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
  2541     AbstractGangTask("ParKnownGarbageTask"),
  2542     _hrSorted(hrSorted), _chunk_size(chunk_size),
  2543     _g1(G1CollectedHeap::heap())
  2544   {}
  2546   void work(int i) {
  2547     ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
  2548     // Back to zero for the claim value.
  2549     _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
  2550                                          HeapRegion::InitialClaimValue);
  2551     jint regions_added = parKnownGarbageCl.marked_regions_added();
  2552     _hrSorted->incNumMarkedHeapRegions(regions_added);
  2553     if (G1PrintParCleanupStats) {
  2554       gclog_or_tty->print("     Thread %d called %d times, added %d regions to list.\n",
  2555                  i, parKnownGarbageCl.invokes(), regions_added);
  2558 };
  2560 void
  2561 G1CollectorPolicy_BestRegionsFirst::
  2562 record_concurrent_mark_cleanup_end(size_t freed_bytes,
  2563                                    size_t max_live_bytes) {
  2564   double start;
  2565   if (G1PrintParCleanupStats) start = os::elapsedTime();
  2566   record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
  2568   _collectionSetChooser->clearMarkedHeapRegions();
  2569   double clear_marked_end;
  2570   if (G1PrintParCleanupStats) {
  2571     clear_marked_end = os::elapsedTime();
  2572     gclog_or_tty->print_cr("  clear marked regions + work1: %8.3f ms.",
  2573                   (clear_marked_end - start)*1000.0);
  2575   if (G1CollectedHeap::use_parallel_gc_threads()) {
  2576     const size_t OverpartitionFactor = 4;
  2577     const size_t MinWorkUnit = 8;
  2578     const size_t WorkUnit =
  2579       MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
  2580            MinWorkUnit);
  2581     _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
  2582                                                              WorkUnit);
  2583     ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
  2584                                             (int) WorkUnit);
  2585     _g1->workers()->run_task(&parKnownGarbageTask);
  2587     assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
  2588            "sanity check");
  2589   } else {
  2590     KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
  2591     _g1->heap_region_iterate(&knownGarbagecl);
  2593   double known_garbage_end;
  2594   if (G1PrintParCleanupStats) {
  2595     known_garbage_end = os::elapsedTime();
  2596     gclog_or_tty->print_cr("  compute known garbage: %8.3f ms.",
  2597                   (known_garbage_end - clear_marked_end)*1000.0);
  2599   _collectionSetChooser->sortMarkedHeapRegions();
  2600   double sort_end;
  2601   if (G1PrintParCleanupStats) {
  2602     sort_end = os::elapsedTime();
  2603     gclog_or_tty->print_cr("  sorting: %8.3f ms.",
  2604                   (sort_end - known_garbage_end)*1000.0);
  2607   record_concurrent_mark_cleanup_end_work2();
  2608   double work2_end;
  2609   if (G1PrintParCleanupStats) {
  2610     work2_end = os::elapsedTime();
  2611     gclog_or_tty->print_cr("  work2: %8.3f ms.",
  2612                   (work2_end - sort_end)*1000.0);
  2616 // Add the heap region at the head of the non-incremental collection set
  2617 void G1CollectorPolicy::
  2618 add_to_collection_set(HeapRegion* hr) {
  2619   assert(_inc_cset_build_state == Active, "Precondition");
  2620   assert(!hr->is_young(), "non-incremental add of young region");
  2622   if (G1PrintHeapRegions) {
  2623     gclog_or_tty->print_cr("added region to cset "
  2624                            "%d:["PTR_FORMAT", "PTR_FORMAT"], "
  2625                            "top "PTR_FORMAT", %s",
  2626                            hr->hrs_index(), hr->bottom(), hr->end(),
  2627                            hr->top(), hr->is_young() ? "YOUNG" : "NOT_YOUNG");
  2630   if (_g1->mark_in_progress())
  2631     _g1->concurrent_mark()->registerCSetRegion(hr);
  2633   assert(!hr->in_collection_set(), "should not already be in the CSet");
  2634   hr->set_in_collection_set(true);
  2635   hr->set_next_in_collection_set(_collection_set);
  2636   _collection_set = hr;
  2637   _collection_set_size++;
  2638   _collection_set_bytes_used_before += hr->used();
  2639   _g1->register_region_with_in_cset_fast_test(hr);
  2642 // Initialize the per-collection-set information
  2643 void G1CollectorPolicy::start_incremental_cset_building() {
  2644   assert(_inc_cset_build_state == Inactive, "Precondition");
  2646   _inc_cset_head = NULL;
  2647   _inc_cset_tail = NULL;
  2648   _inc_cset_size = 0;
  2649   _inc_cset_bytes_used_before = 0;
  2651   if (in_young_gc_mode()) {
  2652     _inc_cset_young_index = 0;
  2655   _inc_cset_max_finger = 0;
  2656   _inc_cset_recorded_young_bytes = 0;
  2657   _inc_cset_recorded_rs_lengths = 0;
  2658   _inc_cset_predicted_elapsed_time_ms = 0;
  2659   _inc_cset_predicted_bytes_to_copy = 0;
  2660   _inc_cset_build_state = Active;
  2663 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
  2664   // This routine is used when:
  2665   // * adding survivor regions to the incremental cset at the end of an
  2666   //   evacuation pause,
  2667   // * adding the current allocation region to the incremental cset
  2668   //   when it is retired, and
  2669   // * updating existing policy information for a region in the
  2670   //   incremental cset via young list RSet sampling.
  2671   // Therefore this routine may be called at a safepoint by the
  2672   // VM thread, or in-between safepoints by mutator threads (when
  2673   // retiring the current allocation region) or a concurrent
  2674   // refine thread (RSet sampling).
  2676   double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
  2677   size_t used_bytes = hr->used();
  2679   _inc_cset_recorded_rs_lengths += rs_length;
  2680   _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
  2682   _inc_cset_bytes_used_before += used_bytes;
  2684   // Cache the values we have added to the aggregated informtion
  2685   // in the heap region in case we have to remove this region from
  2686   // the incremental collection set, or it is updated by the
  2687   // rset sampling code
  2688   hr->set_recorded_rs_length(rs_length);
  2689   hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
  2691 #if PREDICTIONS_VERBOSE
  2692   size_t bytes_to_copy = predict_bytes_to_copy(hr);
  2693   _inc_cset_predicted_bytes_to_copy += bytes_to_copy;
  2695   // Record the number of bytes used in this region
  2696   _inc_cset_recorded_young_bytes += used_bytes;
  2698   // Cache the values we have added to the aggregated informtion
  2699   // in the heap region in case we have to remove this region from
  2700   // the incremental collection set, or it is updated by the
  2701   // rset sampling code
  2702   hr->set_predicted_bytes_to_copy(bytes_to_copy);
  2703 #endif // PREDICTIONS_VERBOSE
  2706 void G1CollectorPolicy::remove_from_incremental_cset_info(HeapRegion* hr) {
  2707   // This routine is currently only called as part of the updating of
  2708   // existing policy information for regions in the incremental cset that
  2709   // is performed by the concurrent refine thread(s) as part of young list
  2710   // RSet sampling. Therefore we should not be at a safepoint.
  2712   assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
  2713   assert(hr->is_young(), "it should be");
  2715   size_t used_bytes = hr->used();
  2716   size_t old_rs_length = hr->recorded_rs_length();
  2717   double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
  2719   // Subtract the old recorded/predicted policy information for
  2720   // the given heap region from the collection set info.
  2721   _inc_cset_recorded_rs_lengths -= old_rs_length;
  2722   _inc_cset_predicted_elapsed_time_ms -= old_elapsed_time_ms;
  2724   _inc_cset_bytes_used_before -= used_bytes;
  2726   // Clear the values cached in the heap region
  2727   hr->set_recorded_rs_length(0);
  2728   hr->set_predicted_elapsed_time_ms(0);
  2730 #if PREDICTIONS_VERBOSE
  2731   size_t old_predicted_bytes_to_copy = hr->predicted_bytes_to_copy();
  2732   _inc_cset_predicted_bytes_to_copy -= old_predicted_bytes_to_copy;
  2734   // Subtract the number of bytes used in this region
  2735   _inc_cset_recorded_young_bytes -= used_bytes;
  2737   // Clear the values cached in the heap region
  2738   hr->set_predicted_bytes_to_copy(0);
  2739 #endif // PREDICTIONS_VERBOSE
  2742 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length) {
  2743   // Update the collection set information that is dependent on the new RS length
  2744   assert(hr->is_young(), "Precondition");
  2746   remove_from_incremental_cset_info(hr);
  2747   add_to_incremental_cset_info(hr, new_rs_length);
  2750 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
  2751   assert( hr->is_young(), "invariant");
  2752   assert( hr->young_index_in_cset() == -1, "invariant" );
  2753   assert(_inc_cset_build_state == Active, "Precondition");
  2755   // We need to clear and set the cached recorded/cached collection set
  2756   // information in the heap region here (before the region gets added
  2757   // to the collection set). An individual heap region's cached values
  2758   // are calculated, aggregated with the policy collection set info,
  2759   // and cached in the heap region here (initially) and (subsequently)
  2760   // by the Young List sampling code.
  2762   size_t rs_length = hr->rem_set()->occupied();
  2763   add_to_incremental_cset_info(hr, rs_length);
  2765   HeapWord* hr_end = hr->end();
  2766   _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
  2768   assert(!hr->in_collection_set(), "invariant");
  2769   hr->set_in_collection_set(true);
  2770   assert( hr->next_in_collection_set() == NULL, "invariant");
  2772   _inc_cset_size++;
  2773   _g1->register_region_with_in_cset_fast_test(hr);
  2775   hr->set_young_index_in_cset((int) _inc_cset_young_index);
  2776   ++_inc_cset_young_index;
  2779 // Add the region at the RHS of the incremental cset
  2780 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
  2781   // We should only ever be appending survivors at the end of a pause
  2782   assert( hr->is_survivor(), "Logic");
  2784   // Do the 'common' stuff
  2785   add_region_to_incremental_cset_common(hr);
  2787   // Now add the region at the right hand side
  2788   if (_inc_cset_tail == NULL) {
  2789     assert(_inc_cset_head == NULL, "invariant");
  2790     _inc_cset_head = hr;
  2791   } else {
  2792     _inc_cset_tail->set_next_in_collection_set(hr);
  2794   _inc_cset_tail = hr;
  2796   if (G1PrintHeapRegions) {
  2797     gclog_or_tty->print_cr(" added region to incremental cset (RHS) "
  2798                   "%d:["PTR_FORMAT", "PTR_FORMAT"], "
  2799                   "top "PTR_FORMAT", young %s",
  2800                   hr->hrs_index(), hr->bottom(), hr->end(),
  2801                   hr->top(), (hr->is_young()) ? "YES" : "NO");
  2805 // Add the region to the LHS of the incremental cset
  2806 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
  2807   // Survivors should be added to the RHS at the end of a pause
  2808   assert(!hr->is_survivor(), "Logic");
  2810   // Do the 'common' stuff
  2811   add_region_to_incremental_cset_common(hr);
  2813   // Add the region at the left hand side
  2814   hr->set_next_in_collection_set(_inc_cset_head);
  2815   if (_inc_cset_head == NULL) {
  2816     assert(_inc_cset_tail == NULL, "Invariant");
  2817     _inc_cset_tail = hr;
  2819   _inc_cset_head = hr;
  2821   if (G1PrintHeapRegions) {
  2822     gclog_or_tty->print_cr(" added region to incremental cset (LHS) "
  2823                   "%d:["PTR_FORMAT", "PTR_FORMAT"], "
  2824                   "top "PTR_FORMAT", young %s",
  2825                   hr->hrs_index(), hr->bottom(), hr->end(),
  2826                   hr->top(), (hr->is_young()) ? "YES" : "NO");
  2830 #ifndef PRODUCT
  2831 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
  2832   assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
  2834   st->print_cr("\nCollection_set:");
  2835   HeapRegion* csr = list_head;
  2836   while (csr != NULL) {
  2837     HeapRegion* next = csr->next_in_collection_set();
  2838     assert(csr->in_collection_set(), "bad CS");
  2839     st->print_cr("  [%08x-%08x], t: %08x, P: %08x, N: %08x, C: %08x, "
  2840                  "age: %4d, y: %d, surv: %d",
  2841                         csr->bottom(), csr->end(),
  2842                         csr->top(),
  2843                         csr->prev_top_at_mark_start(),
  2844                         csr->next_top_at_mark_start(),
  2845                         csr->top_at_conc_mark_count(),
  2846                         csr->age_in_surv_rate_group_cond(),
  2847                         csr->is_young(),
  2848                         csr->is_survivor());
  2849     csr = next;
  2852 #endif // !PRODUCT
  2854 void
  2855 G1CollectorPolicy_BestRegionsFirst::choose_collection_set(
  2856                                                   double target_pause_time_ms) {
  2857   // Set this here - in case we're not doing young collections.
  2858   double non_young_start_time_sec = os::elapsedTime();
  2860   start_recording_regions();
  2862   guarantee(target_pause_time_ms > 0.0,
  2863             err_msg("target_pause_time_ms = %1.6lf should be positive",
  2864                     target_pause_time_ms));
  2865   guarantee(_collection_set == NULL, "Precondition");
  2867   double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
  2868   double predicted_pause_time_ms = base_time_ms;
  2870   double time_remaining_ms = target_pause_time_ms - base_time_ms;
  2872   // the 10% and 50% values are arbitrary...
  2873   if (time_remaining_ms < 0.10 * target_pause_time_ms) {
  2874     time_remaining_ms = 0.50 * target_pause_time_ms;
  2875     _within_target = false;
  2876   } else {
  2877     _within_target = true;
  2880   // We figure out the number of bytes available for future to-space.
  2881   // For new regions without marking information, we must assume the
  2882   // worst-case of complete survival.  If we have marking information for a
  2883   // region, we can bound the amount of live data.  We can add a number of
  2884   // such regions, as long as the sum of the live data bounds does not
  2885   // exceed the available evacuation space.
  2886   size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes;
  2888   size_t expansion_bytes =
  2889     _g1->expansion_regions() * HeapRegion::GrainBytes;
  2891   _collection_set_bytes_used_before = 0;
  2892   _collection_set_size = 0;
  2894   // Adjust for expansion and slop.
  2895   max_live_bytes = max_live_bytes + expansion_bytes;
  2897   assert(_g1->regions_accounted_for(), "Region leakage!");
  2899   HeapRegion* hr;
  2900   if (in_young_gc_mode()) {
  2901     double young_start_time_sec = os::elapsedTime();
  2903     if (G1PolicyVerbose > 0) {
  2904       gclog_or_tty->print_cr("Adding %d young regions to the CSet",
  2905                     _g1->young_list()->length());
  2908     _young_cset_length  = 0;
  2909     _last_young_gc_full = full_young_gcs() ? true : false;
  2911     if (_last_young_gc_full)
  2912       ++_full_young_pause_num;
  2913     else
  2914       ++_partial_young_pause_num;
  2916     // The young list is laid with the survivor regions from the previous
  2917     // pause are appended to the RHS of the young list, i.e.
  2918     //   [Newly Young Regions ++ Survivors from last pause].
  2920     hr = _g1->young_list()->first_survivor_region();
  2921     while (hr != NULL) {
  2922       assert(hr->is_survivor(), "badly formed young list");
  2923       hr->set_young();
  2924       hr = hr->get_next_young_region();
  2927     // Clear the fields that point to the survivor list - they are
  2928     // all young now.
  2929     _g1->young_list()->clear_survivors();
  2931     if (_g1->mark_in_progress())
  2932       _g1->concurrent_mark()->register_collection_set_finger(_inc_cset_max_finger);
  2934     _young_cset_length = _inc_cset_young_index;
  2935     _collection_set = _inc_cset_head;
  2936     _collection_set_size = _inc_cset_size;
  2937     _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
  2939     // For young regions in the collection set, we assume the worst
  2940     // case of complete survival
  2941     max_live_bytes -= _inc_cset_size * HeapRegion::GrainBytes;
  2943     time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms;
  2944     predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
  2946     // The number of recorded young regions is the incremental
  2947     // collection set's current size
  2948     set_recorded_young_regions(_inc_cset_size);
  2949     set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
  2950     set_recorded_young_bytes(_inc_cset_recorded_young_bytes);
  2951 #if PREDICTIONS_VERBOSE
  2952     set_predicted_bytes_to_copy(_inc_cset_predicted_bytes_to_copy);
  2953 #endif // PREDICTIONS_VERBOSE
  2955     if (G1PolicyVerbose > 0) {
  2956       gclog_or_tty->print_cr("  Added " PTR_FORMAT " Young Regions to CS.",
  2957                              _inc_cset_size);
  2958       gclog_or_tty->print_cr("    (" SIZE_FORMAT " KB left in heap.)",
  2959                             max_live_bytes/K);
  2962     assert(_inc_cset_size == _g1->young_list()->length(), "Invariant");
  2964     double young_end_time_sec = os::elapsedTime();
  2965     _recorded_young_cset_choice_time_ms =
  2966       (young_end_time_sec - young_start_time_sec) * 1000.0;
  2968     // We are doing young collections so reset this.
  2969     non_young_start_time_sec = young_end_time_sec;
  2971     // Note we can use either _collection_set_size or
  2972     // _young_cset_length here
  2973     if (_collection_set_size > 0 && _last_young_gc_full) {
  2974       // don't bother adding more regions...
  2975       goto choose_collection_set_end;
  2979   if (!in_young_gc_mode() || !full_young_gcs()) {
  2980     bool should_continue = true;
  2981     NumberSeq seq;
  2982     double avg_prediction = 100000000000000000.0; // something very large
  2984     do {
  2985       hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
  2986                                                       avg_prediction);
  2987       if (hr != NULL) {
  2988         double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
  2989         time_remaining_ms -= predicted_time_ms;
  2990         predicted_pause_time_ms += predicted_time_ms;
  2991         add_to_collection_set(hr);
  2992         record_non_young_cset_region(hr);
  2993         max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
  2994         if (G1PolicyVerbose > 0) {
  2995           gclog_or_tty->print_cr("    (" SIZE_FORMAT " KB left in heap.)",
  2996                         max_live_bytes/K);
  2998         seq.add(predicted_time_ms);
  2999         avg_prediction = seq.avg() + seq.sd();
  3001       should_continue =
  3002         ( hr != NULL) &&
  3003         ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0
  3004           : _collection_set_size < _young_list_fixed_length );
  3005     } while (should_continue);
  3007     if (!adaptive_young_list_length() &&
  3008         _collection_set_size < _young_list_fixed_length)
  3009       _should_revert_to_full_young_gcs  = true;
  3012 choose_collection_set_end:
  3013   stop_incremental_cset_building();
  3015   count_CS_bytes_used();
  3017   end_recording_regions();
  3019   double non_young_end_time_sec = os::elapsedTime();
  3020   _recorded_non_young_cset_choice_time_ms =
  3021     (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
  3024 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
  3025   G1CollectorPolicy::record_full_collection_end();
  3026   _collectionSetChooser->updateAfterFullCollection();
  3029 void G1CollectorPolicy_BestRegionsFirst::
  3030 expand_if_possible(size_t numRegions) {
  3031   size_t expansion_bytes = numRegions * HeapRegion::GrainBytes;
  3032   _g1->expand(expansion_bytes);
  3035 void G1CollectorPolicy_BestRegionsFirst::
  3036 record_collection_pause_end() {
  3037   G1CollectorPolicy::record_collection_pause_end();
  3038   assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");

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