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

Fri, 16 Jan 2009 13:02:20 -0500

author
tonyp
date
Fri, 16 Jan 2009 13:02:20 -0500
changeset 961
818efdefcc99
parent 905
ad8c8ca4ab0f
child 980
58054a18d735
permissions
-rw-r--r--

6484956: G1: improve evacuation pause efficiency
Summary: A bunch of performance optimizations to decrease GC pause times in G1.
Reviewed-by: apetrusenko, jmasa, iveresov

     1 /*
     2  * Copyright 2001-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
    21  * have any questions.
    22  *
    23  */
    25 #include "incls/_precompiled.incl"
    26 #include "incls/_g1CollectorPolicy.cpp.incl"
    28 #define PREDICTIONS_VERBOSE 0
    30 // <NEW PREDICTION>
    32 // Different defaults for different number of GC threads
    33 // They were chosen by running GCOld and SPECjbb on debris with different
    34 //   numbers of GC threads and choosing them based on the results
    36 // all the same
    37 static double rs_length_diff_defaults[] = {
    38   0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
    39 };
    41 static double cost_per_card_ms_defaults[] = {
    42   0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
    43 };
    45 static double cost_per_scan_only_region_ms_defaults[] = {
    46   1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
    47 };
    49 // all the same
    50 static double fully_young_cards_per_entry_ratio_defaults[] = {
    51   1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
    52 };
    54 static double cost_per_entry_ms_defaults[] = {
    55   0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
    56 };
    58 static double cost_per_byte_ms_defaults[] = {
    59   0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
    60 };
    62 // these should be pretty consistent
    63 static double constant_other_time_ms_defaults[] = {
    64   5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
    65 };
    68 static double young_other_cost_per_region_ms_defaults[] = {
    69   0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
    70 };
    72 static double non_young_other_cost_per_region_ms_defaults[] = {
    73   1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
    74 };
    76 // </NEW PREDICTION>
    78 G1CollectorPolicy::G1CollectorPolicy() :
    79   _parallel_gc_threads((ParallelGCThreads > 0) ? ParallelGCThreads : 1),
    80   _n_pauses(0),
    81   _recent_CH_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    82   _recent_G1_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    83   _recent_evac_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    84   _recent_pause_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    85   _recent_rs_sizes(new TruncatedSeq(NumPrevPausesForHeuristics)),
    86   _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
    87   _all_pause_times_ms(new NumberSeq()),
    88   _stop_world_start(0.0),
    89   _all_stop_world_times_ms(new NumberSeq()),
    90   _all_yield_times_ms(new NumberSeq()),
    92   _all_mod_union_times_ms(new NumberSeq()),
    94   _non_pop_summary(new NonPopSummary()),
    95   _pop_summary(new PopSummary()),
    96   _non_pop_abandoned_summary(new NonPopAbandonedSummary()),
    97   _pop_abandoned_summary(new PopAbandonedSummary()),
    99   _cur_clear_ct_time_ms(0.0),
   101   _region_num_young(0),
   102   _region_num_tenured(0),
   103   _prev_region_num_young(0),
   104   _prev_region_num_tenured(0),
   106   _aux_num(10),
   107   _all_aux_times_ms(new NumberSeq[_aux_num]),
   108   _cur_aux_start_times_ms(new double[_aux_num]),
   109   _cur_aux_times_ms(new double[_aux_num]),
   110   _cur_aux_times_set(new bool[_aux_num]),
   112   _pop_compute_rc_start(0.0),
   113   _pop_evac_start(0.0),
   115   _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   116   _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   117   _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   119   // <NEW PREDICTION>
   121   _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   122   _prev_collection_pause_end_ms(0.0),
   123   _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
   124   _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
   125   _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   126   _cost_per_scan_only_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   127   _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
   128   _partially_young_cards_per_entry_ratio_seq(
   129                                          new TruncatedSeq(TruncatedSeqLength)),
   130   _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   131   _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   132   _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   133   _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
   134   _cost_per_scan_only_region_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
   135   _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   136   _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   137   _non_young_other_cost_per_region_ms_seq(
   138                                          new TruncatedSeq(TruncatedSeqLength)),
   140   _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
   141   _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
   142   _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
   144   _pause_time_target_ms((double) G1MaxPauseTimeMS),
   146   // </NEW PREDICTION>
   148   _in_young_gc_mode(false),
   149   _full_young_gcs(true),
   150   _full_young_pause_num(0),
   151   _partial_young_pause_num(0),
   153   _during_marking(false),
   154   _in_marking_window(false),
   155   _in_marking_window_im(false),
   157   _known_garbage_ratio(0.0),
   158   _known_garbage_bytes(0),
   160   _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
   161   _target_pause_time_ms(-1.0),
   163    _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
   165   _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
   166   _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
   168   _recent_avg_pause_time_ratio(0.0),
   169   _num_markings(0),
   170   _n_marks(0),
   171   _n_pauses_at_mark_end(0),
   173   _all_full_gc_times_ms(new NumberSeq()),
   175   _conc_refine_enabled(0),
   176   _conc_refine_zero_traversals(0),
   177   _conc_refine_max_traversals(0),
   178   _conc_refine_current_delta(G1ConcRefineInitialDelta),
   180   // G1PausesBtwnConcMark defaults to -1
   181   // so the hack is to do the cast  QQQ FIXME
   182   _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
   183   _n_marks_since_last_pause(0),
   184   _conc_mark_initiated(false),
   185   _should_initiate_conc_mark(false),
   186   _should_revert_to_full_young_gcs(false),
   187   _last_full_young_gc(false),
   189   _prev_collection_pause_used_at_end_bytes(0),
   191   _collection_set(NULL),
   192 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
   193 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
   194 #endif // _MSC_VER
   196   _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
   197                                                  G1YoungSurvRateNumRegionsSummary)),
   198   _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
   199                                               G1YoungSurvRateNumRegionsSummary))
   200   // add here any more surv rate groups
   201 {
   202   _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
   203   _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
   205   _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
   206   _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
   207   _par_last_scan_only_times_ms = new double[_parallel_gc_threads];
   208   _par_last_scan_only_regions_scanned = new double[_parallel_gc_threads];
   210   _par_last_update_rs_start_times_ms = new double[_parallel_gc_threads];
   211   _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
   212   _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
   214   _par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads];
   215   _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
   216   _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads];
   218   _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
   220   _par_last_termination_times_ms = new double[_parallel_gc_threads];
   222   // we store the data from the first pass during popularity pauses
   223   _pop_par_last_update_rs_start_times_ms = new double[_parallel_gc_threads];
   224   _pop_par_last_update_rs_times_ms = new double[_parallel_gc_threads];
   225   _pop_par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
   227   _pop_par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads];
   228   _pop_par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
   230   _pop_par_last_closure_app_times_ms = new double[_parallel_gc_threads];
   232   // start conservatively
   233   _expensive_region_limit_ms = 0.5 * (double) G1MaxPauseTimeMS;
   235   // <NEW PREDICTION>
   237   int index;
   238   if (ParallelGCThreads == 0)
   239     index = 0;
   240   else if (ParallelGCThreads > 8)
   241     index = 7;
   242   else
   243     index = ParallelGCThreads - 1;
   245   _pending_card_diff_seq->add(0.0);
   246   _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
   247   _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
   248   _cost_per_scan_only_region_ms_seq->add(
   249                                  cost_per_scan_only_region_ms_defaults[index]);
   250   _fully_young_cards_per_entry_ratio_seq->add(
   251                             fully_young_cards_per_entry_ratio_defaults[index]);
   252   _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
   253   _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
   254   _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
   255   _young_other_cost_per_region_ms_seq->add(
   256                                young_other_cost_per_region_ms_defaults[index]);
   257   _non_young_other_cost_per_region_ms_seq->add(
   258                            non_young_other_cost_per_region_ms_defaults[index]);
   260   // </NEW PREDICTION>
   262   double time_slice  = (double) G1TimeSliceMS / 1000.0;
   263   double max_gc_time = (double) G1MaxPauseTimeMS / 1000.0;
   264   guarantee(max_gc_time < time_slice,
   265             "Max GC time should not be greater than the time slice");
   266   _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
   267   _sigma = (double) G1ConfidencePerc / 100.0;
   269   // start conservatively (around 50ms is about right)
   270   _concurrent_mark_init_times_ms->add(0.05);
   271   _concurrent_mark_remark_times_ms->add(0.05);
   272   _concurrent_mark_cleanup_times_ms->add(0.20);
   273   _tenuring_threshold = MaxTenuringThreshold;
   275   initialize_all();
   276 }
   278 // Increment "i", mod "len"
   279 static void inc_mod(int& i, int len) {
   280   i++; if (i == len) i = 0;
   281 }
   283 void G1CollectorPolicy::initialize_flags() {
   284   set_min_alignment(HeapRegion::GrainBytes);
   285   set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
   286   CollectorPolicy::initialize_flags();
   287 }
   289 void G1CollectorPolicy::init() {
   290   // Set aside an initial future to_space.
   291   _g1 = G1CollectedHeap::heap();
   292   size_t regions = Universe::heap()->capacity() / HeapRegion::GrainBytes;
   294   assert(Heap_lock->owned_by_self(), "Locking discipline.");
   296   if (G1SteadyStateUsed < 50) {
   297     vm_exit_during_initialization("G1SteadyStateUsed must be at least 50%.");
   298   }
   299   if (UseConcMarkSweepGC) {
   300     vm_exit_during_initialization("-XX:+UseG1GC is incompatible with "
   301                                   "-XX:+UseConcMarkSweepGC.");
   302   }
   304   if (G1Gen) {
   305     _in_young_gc_mode = true;
   307     if (G1YoungGenSize == 0) {
   308       set_adaptive_young_list_length(true);
   309       _young_list_fixed_length = 0;
   310     } else {
   311       set_adaptive_young_list_length(false);
   312       _young_list_fixed_length = (G1YoungGenSize / HeapRegion::GrainBytes);
   313     }
   314      _free_regions_at_end_of_collection = _g1->free_regions();
   315      _scan_only_regions_at_end_of_collection = 0;
   316      calculate_young_list_min_length();
   317      guarantee( _young_list_min_length == 0, "invariant, not enough info" );
   318      calculate_young_list_target_config();
   319    } else {
   320      _young_list_fixed_length = 0;
   321     _in_young_gc_mode = false;
   322   }
   323 }
   325 void G1CollectorPolicy::calculate_young_list_min_length() {
   326   _young_list_min_length = 0;
   328   if (!adaptive_young_list_length())
   329     return;
   331   if (_alloc_rate_ms_seq->num() > 3) {
   332     double now_sec = os::elapsedTime();
   333     double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
   334     double alloc_rate_ms = predict_alloc_rate_ms();
   335     int min_regions = (int) ceil(alloc_rate_ms * when_ms);
   336     int current_region_num = (int) _g1->young_list_length();
   337     _young_list_min_length = min_regions + current_region_num;
   338   }
   339 }
   341 void G1CollectorPolicy::calculate_young_list_target_config() {
   342   if (adaptive_young_list_length()) {
   343     size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
   344     calculate_young_list_target_config(rs_lengths);
   345   } else {
   346     if (full_young_gcs())
   347       _young_list_target_length = _young_list_fixed_length;
   348     else
   349       _young_list_target_length = _young_list_fixed_length / 2;
   350     _young_list_target_length = MAX2(_young_list_target_length, (size_t)1);
   351     size_t so_length = calculate_optimal_so_length(_young_list_target_length);
   352     guarantee( so_length < _young_list_target_length, "invariant" );
   353     _young_list_so_prefix_length = so_length;
   354   }
   355 }
   357 // This method calculate the optimal scan-only set for a fixed young
   358 // gen size. I couldn't work out how to reuse the more elaborate one,
   359 // i.e. calculate_young_list_target_config(rs_length), as the loops are
   360 // fundamentally different (the other one finds a config for different
   361 // S-O lengths, whereas here we need to do the opposite).
   362 size_t G1CollectorPolicy::calculate_optimal_so_length(
   363                                                     size_t young_list_length) {
   364   if (!G1UseScanOnlyPrefix)
   365     return 0;
   367   if (_all_pause_times_ms->num() < 3) {
   368     // we won't use a scan-only set at the beginning to allow the rest
   369     // of the predictors to warm up
   370     return 0;
   371   }
   373   if (_cost_per_scan_only_region_ms_seq->num() < 3) {
   374     // then, we'll only set the S-O set to 1 for a little bit of time,
   375     // to get enough information on the scanning cost
   376     return 1;
   377   }
   379   size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
   380   size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
   381   size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
   382   size_t scanned_cards;
   383   if (full_young_gcs())
   384     scanned_cards = predict_young_card_num(adj_rs_lengths);
   385   else
   386     scanned_cards = predict_non_young_card_num(adj_rs_lengths);
   387   double base_time_ms = predict_base_elapsed_time_ms(pending_cards,
   388                                                      scanned_cards);
   390   size_t so_length = 0;
   391   double max_gc_eff = 0.0;
   392   for (size_t i = 0; i < young_list_length; ++i) {
   393     double gc_eff = 0.0;
   394     double pause_time_ms = 0.0;
   395     predict_gc_eff(young_list_length, i, base_time_ms,
   396                    &gc_eff, &pause_time_ms);
   397     if (gc_eff > max_gc_eff) {
   398       max_gc_eff = gc_eff;
   399       so_length = i;
   400     }
   401   }
   403   // set it to 95% of the optimal to make sure we sample the "area"
   404   // around the optimal length to get up-to-date survival rate data
   405   return so_length * 950 / 1000;
   406 }
   408 // This is a really cool piece of code! It finds the best
   409 // target configuration (young length / scan-only prefix length) so
   410 // that GC efficiency is maximized and that we also meet a pause
   411 // time. It's a triple nested loop. These loops are explained below
   412 // from the inside-out :-)
   413 //
   414 // (a) The innermost loop will try to find the optimal young length
   415 // for a fixed S-O length. It uses a binary search to speed up the
   416 // process. We assume that, for a fixed S-O length, as we add more
   417 // young regions to the CSet, the GC efficiency will only go up (I'll
   418 // skip the proof). So, using a binary search to optimize this process
   419 // makes perfect sense.
   420 //
   421 // (b) The middle loop will fix the S-O length before calling the
   422 // innermost one. It will vary it between two parameters, increasing
   423 // it by a given increment.
   424 //
   425 // (c) The outermost loop will call the middle loop three times.
   426 //   (1) The first time it will explore all possible S-O length values
   427 //   from 0 to as large as it can get, using a coarse increment (to
   428 //   quickly "home in" to where the optimal seems to be).
   429 //   (2) The second time it will explore the values around the optimal
   430 //   that was found by the first iteration using a fine increment.
   431 //   (3) Once the optimal config has been determined by the second
   432 //   iteration, we'll redo the calculation, but setting the S-O length
   433 //   to 95% of the optimal to make sure we sample the "area"
   434 //   around the optimal length to get up-to-date survival rate data
   435 //
   436 // Termination conditions for the iterations are several: the pause
   437 // time is over the limit, we do not have enough to-space, etc.
   439 void G1CollectorPolicy::calculate_young_list_target_config(size_t rs_lengths) {
   440   guarantee( adaptive_young_list_length(), "pre-condition" );
   442   double start_time_sec = os::elapsedTime();
   443   size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1MinReservePerc);
   444   min_reserve_perc = MIN2((size_t) 50, min_reserve_perc);
   445   size_t reserve_regions =
   446     (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0);
   448   if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
   449     // we are in fully-young mode and there are free regions in the heap
   451     size_t min_so_length = 0;
   452     size_t max_so_length = 0;
   454     if (G1UseScanOnlyPrefix) {
   455       if (_all_pause_times_ms->num() < 3) {
   456         // we won't use a scan-only set at the beginning to allow the rest
   457         // of the predictors to warm up
   458         min_so_length = 0;
   459         max_so_length = 0;
   460       } else if (_cost_per_scan_only_region_ms_seq->num() < 3) {
   461         // then, we'll only set the S-O set to 1 for a little bit of time,
   462         // to get enough information on the scanning cost
   463         min_so_length = 1;
   464         max_so_length = 1;
   465       } else if (_in_marking_window || _last_full_young_gc) {
   466         // no S-O prefix during a marking phase either, as at the end
   467         // of the marking phase we'll have to use a very small young
   468         // length target to fill up the rest of the CSet with
   469         // non-young regions and, if we have lots of scan-only regions
   470         // left-over, we will not be able to add any more non-young
   471         // regions.
   472         min_so_length = 0;
   473         max_so_length = 0;
   474       } else {
   475         // this is the common case; we'll never reach the maximum, we
   476         // one of the end conditions will fire well before that
   477         // (hopefully!)
   478         min_so_length = 0;
   479         max_so_length = _free_regions_at_end_of_collection - 1;
   480       }
   481     } else {
   482       // no S-O prefix, as the switch is not set, but we still need to
   483       // do one iteration to calculate the best young target that
   484       // meets the pause time; this way we reuse the same code instead
   485       // of replicating it
   486       min_so_length = 0;
   487       max_so_length = 0;
   488     }
   490     double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
   491     size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
   492     size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
   493     size_t scanned_cards;
   494     if (full_young_gcs())
   495       scanned_cards = predict_young_card_num(adj_rs_lengths);
   496     else
   497       scanned_cards = predict_non_young_card_num(adj_rs_lengths);
   498     // calculate this once, so that we don't have to recalculate it in
   499     // the innermost loop
   500     double base_time_ms = predict_base_elapsed_time_ms(pending_cards,
   501                                                        scanned_cards);
   503     // the result
   504     size_t final_young_length = 0;
   505     size_t final_so_length = 0;
   506     double final_gc_eff = 0.0;
   507     // we'll also keep track of how many times we go into the inner loop
   508     // this is for profiling reasons
   509     size_t calculations = 0;
   511     // this determines which of the three iterations the outer loop is in
   512     typedef enum {
   513       pass_type_coarse,
   514       pass_type_fine,
   515       pass_type_final
   516     } pass_type_t;
   518     // range of the outer loop's iteration
   519     size_t from_so_length   = min_so_length;
   520     size_t to_so_length     = max_so_length;
   521     guarantee( from_so_length <= to_so_length, "invariant" );
   523     // this will keep the S-O length that's found by the second
   524     // iteration of the outer loop; we'll keep it just in case the third
   525     // iteration fails to find something
   526     size_t fine_so_length   = 0;
   528     // the increment step for the coarse (first) iteration
   529     size_t so_coarse_increments = 5;
   531     // the common case, we'll start with the coarse iteration
   532     pass_type_t pass = pass_type_coarse;
   533     size_t so_length_incr = so_coarse_increments;
   535     if (from_so_length == to_so_length) {
   536       // not point in doing the coarse iteration, we'll go directly into
   537       // the fine one (we essentially trying to find the optimal young
   538       // length for a fixed S-O length).
   539       so_length_incr = 1;
   540       pass = pass_type_final;
   541     } else if (to_so_length - from_so_length < 3 * so_coarse_increments) {
   542       // again, the range is too short so no point in foind the coarse
   543       // iteration either
   544       so_length_incr = 1;
   545       pass = pass_type_fine;
   546     }
   548     bool done = false;
   549     // this is the outermost loop
   550     while (!done) {
   551 #if 0
   552       // leave this in for debugging, just in case
   553       gclog_or_tty->print_cr("searching between " SIZE_FORMAT " and " SIZE_FORMAT
   554                              ", incr " SIZE_FORMAT ", pass %s",
   555                              from_so_length, to_so_length, so_length_incr,
   556                              (pass == pass_type_coarse) ? "coarse" :
   557                              (pass == pass_type_fine) ? "fine" : "final");
   558 #endif // 0
   560       size_t so_length = from_so_length;
   561       size_t init_free_regions =
   562         MAX2((size_t)0,
   563              _free_regions_at_end_of_collection +
   564              _scan_only_regions_at_end_of_collection - reserve_regions);
   566       // this determines whether a configuration was found
   567       bool gc_eff_set = false;
   568       // this is the middle loop
   569       while (so_length <= to_so_length) {
   570         // base time, which excludes region-related time; again we
   571         // calculate it once to avoid recalculating it in the
   572         // innermost loop
   573         double base_time_with_so_ms =
   574                            base_time_ms + predict_scan_only_time_ms(so_length);
   575         // it's already over the pause target, go around
   576         if (base_time_with_so_ms > target_pause_time_ms)
   577           break;
   579         size_t starting_young_length = so_length+1;
   581         // we make sure that the short young length that makes sense
   582         // (one more than the S-O length) is feasible
   583         size_t min_young_length = starting_young_length;
   584         double min_gc_eff;
   585         bool min_ok;
   586         ++calculations;
   587         min_ok = predict_gc_eff(min_young_length, so_length,
   588                                 base_time_with_so_ms,
   589                                 init_free_regions, target_pause_time_ms,
   590                                 &min_gc_eff);
   592         if (min_ok) {
   593           // the shortest young length is indeed feasible; we'll know
   594           // set up the max young length and we'll do a binary search
   595           // between min_young_length and max_young_length
   596           size_t max_young_length = _free_regions_at_end_of_collection - 1;
   597           double max_gc_eff = 0.0;
   598           bool max_ok = false;
   600           // the innermost loop! (finally!)
   601           while (max_young_length > min_young_length) {
   602             // we'll make sure that min_young_length is always at a
   603             // feasible config
   604             guarantee( min_ok, "invariant" );
   606             ++calculations;
   607             max_ok = predict_gc_eff(max_young_length, so_length,
   608                                     base_time_with_so_ms,
   609                                     init_free_regions, target_pause_time_ms,
   610                                     &max_gc_eff);
   612             size_t diff = (max_young_length - min_young_length) / 2;
   613             if (max_ok) {
   614               min_young_length = max_young_length;
   615               min_gc_eff = max_gc_eff;
   616               min_ok = true;
   617             }
   618             max_young_length = min_young_length + diff;
   619           }
   621           // the innermost loop found a config
   622           guarantee( min_ok, "invariant" );
   623           if (min_gc_eff > final_gc_eff) {
   624             // it's the best config so far, so we'll keep it
   625             final_gc_eff = min_gc_eff;
   626             final_young_length = min_young_length;
   627             final_so_length = so_length;
   628             gc_eff_set = true;
   629           }
   630         }
   632         // incremental the fixed S-O length and go around
   633         so_length += so_length_incr;
   634       }
   636       // this is the end of the outermost loop and we need to decide
   637       // what to do during the next iteration
   638       if (pass == pass_type_coarse) {
   639         // we just did the coarse pass (first iteration)
   641         if (!gc_eff_set)
   642           // we didn't find a feasible config so we'll just bail out; of
   643           // course, it might be the case that we missed it; but I'd say
   644           // it's a bit unlikely
   645           done = true;
   646         else {
   647           // We did find a feasible config with optimal GC eff during
   648           // the first pass. So the second pass we'll only consider the
   649           // S-O lengths around that config with a fine increment.
   651           guarantee( so_length_incr == so_coarse_increments, "invariant" );
   652           guarantee( final_so_length >= min_so_length, "invariant" );
   654 #if 0
   655           // leave this in for debugging, just in case
   656           gclog_or_tty->print_cr("  coarse pass: SO length " SIZE_FORMAT,
   657                                  final_so_length);
   658 #endif // 0
   660           from_so_length =
   661             (final_so_length - min_so_length > so_coarse_increments) ?
   662             final_so_length - so_coarse_increments + 1 : min_so_length;
   663           to_so_length =
   664             (max_so_length - final_so_length > so_coarse_increments) ?
   665             final_so_length + so_coarse_increments - 1 : max_so_length;
   667           pass = pass_type_fine;
   668           so_length_incr = 1;
   669         }
   670       } else if (pass == pass_type_fine) {
   671         // we just finished the second pass
   673         if (!gc_eff_set) {
   674           // we didn't find a feasible config (yes, it's possible;
   675           // notice that, sometimes, we go directly into the fine
   676           // iteration and skip the coarse one) so we bail out
   677           done = true;
   678         } else {
   679           // We did find a feasible config with optimal GC eff
   680           guarantee( so_length_incr == 1, "invariant" );
   682           if (final_so_length == 0) {
   683             // The config is of an empty S-O set, so we'll just bail out
   684             done = true;
   685           } else {
   686             // we'll go around once more, setting the S-O length to 95%
   687             // of the optimal
   688             size_t new_so_length = 950 * final_so_length / 1000;
   690 #if 0
   691             // leave this in for debugging, just in case
   692             gclog_or_tty->print_cr("  fine pass: SO length " SIZE_FORMAT
   693                                    ", setting it to " SIZE_FORMAT,
   694                                     final_so_length, new_so_length);
   695 #endif // 0
   697             from_so_length = new_so_length;
   698             to_so_length = new_so_length;
   699             fine_so_length = final_so_length;
   701             pass = pass_type_final;
   702           }
   703         }
   704       } else if (pass == pass_type_final) {
   705         // we just finished the final (third) pass
   707         if (!gc_eff_set)
   708           // we didn't find a feasible config, so we'll just use the one
   709           // we found during the second pass, which we saved
   710           final_so_length = fine_so_length;
   712         // and we're done!
   713         done = true;
   714       } else {
   715         guarantee( false, "should never reach here" );
   716       }
   718       // we now go around the outermost loop
   719     }
   721     // we should have at least one region in the target young length
   722     _young_list_target_length = MAX2((size_t) 1, final_young_length);
   723     if (final_so_length >= final_young_length)
   724       // and we need to ensure that the S-O length is not greater than
   725       // the target young length (this is being a bit careful)
   726       final_so_length = 0;
   727     _young_list_so_prefix_length = final_so_length;
   728     guarantee( !_in_marking_window || !_last_full_young_gc ||
   729                _young_list_so_prefix_length == 0, "invariant" );
   731     // let's keep an eye of how long we spend on this calculation
   732     // right now, I assume that we'll print it when we need it; we
   733     // should really adde it to the breakdown of a pause
   734     double end_time_sec = os::elapsedTime();
   735     double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
   737 #if 0
   738     // leave this in for debugging, just in case
   739     gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT
   740                            ", SO = " SIZE_FORMAT ", "
   741                            "elapsed %1.2lf ms, calcs: " SIZE_FORMAT " (%s%s) "
   742                            SIZE_FORMAT SIZE_FORMAT,
   743                            target_pause_time_ms,
   744                            _young_list_target_length - _young_list_so_prefix_length,
   745                            _young_list_so_prefix_length,
   746                            elapsed_time_ms,
   747                            calculations,
   748                            full_young_gcs() ? "full" : "partial",
   749                            should_initiate_conc_mark() ? " i-m" : "",
   750                            in_marking_window(),
   751                            in_marking_window_im());
   752 #endif // 0
   754     if (_young_list_target_length < _young_list_min_length) {
   755       // bummer; this means that, if we do a pause when the optimal
   756       // config dictates, we'll violate the pause spacing target (the
   757       // min length was calculate based on the application's current
   758       // alloc rate);
   760       // so, we have to bite the bullet, and allocate the minimum
   761       // number. We'll violate our target, but we just can't meet it.
   763       size_t so_length = 0;
   764       // a note further up explains why we do not want an S-O length
   765       // during marking
   766       if (!_in_marking_window && !_last_full_young_gc)
   767         // but we can still try to see whether we can find an optimal
   768         // S-O length
   769         so_length = calculate_optimal_so_length(_young_list_min_length);
   771 #if 0
   772       // leave this in for debugging, just in case
   773       gclog_or_tty->print_cr("adjusted target length from "
   774                              SIZE_FORMAT " to " SIZE_FORMAT
   775                              ", SO " SIZE_FORMAT,
   776                              _young_list_target_length, _young_list_min_length,
   777                              so_length);
   778 #endif // 0
   780       _young_list_target_length =
   781         MAX2(_young_list_min_length, (size_t)1);
   782       _young_list_so_prefix_length = so_length;
   783     }
   784   } else {
   785     // we are in a partially-young mode or we've run out of regions (due
   786     // to evacuation failure)
   788 #if 0
   789     // leave this in for debugging, just in case
   790     gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
   791                            ", SO " SIZE_FORMAT,
   792                            _young_list_min_length, 0);
   793 #endif // 0
   795     // we'll do the pause as soon as possible and with no S-O prefix
   796     // (see above for the reasons behind the latter)
   797     _young_list_target_length =
   798       MAX2(_young_list_min_length, (size_t) 1);
   799     _young_list_so_prefix_length = 0;
   800   }
   802   _rs_lengths_prediction = rs_lengths;
   803 }
   805 // This is used by: calculate_optimal_so_length(length). It returns
   806 // the GC eff and predicted pause time for a particular config
   807 void
   808 G1CollectorPolicy::predict_gc_eff(size_t young_length,
   809                                   size_t so_length,
   810                                   double base_time_ms,
   811                                   double* ret_gc_eff,
   812                                   double* ret_pause_time_ms) {
   813   double so_time_ms = predict_scan_only_time_ms(so_length);
   814   double accum_surv_rate_adj = 0.0;
   815   if (so_length > 0)
   816     accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
   817   double accum_surv_rate =
   818     accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
   819   size_t bytes_to_copy =
   820     (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
   821   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
   822   double young_other_time_ms =
   823                        predict_young_other_time_ms(young_length - so_length);
   824   double pause_time_ms =
   825                 base_time_ms + so_time_ms + copy_time_ms + young_other_time_ms;
   826   size_t reclaimed_bytes =
   827     (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
   828   double gc_eff = (double) reclaimed_bytes / pause_time_ms;
   830   *ret_gc_eff = gc_eff;
   831   *ret_pause_time_ms = pause_time_ms;
   832 }
   834 // This is used by: calculate_young_list_target_config(rs_length). It
   835 // returns the GC eff of a particular config. It returns false if that
   836 // config violates any of the end conditions of the search in the
   837 // calling method, or true upon success. The end conditions were put
   838 // here since it's called twice and it was best not to replicate them
   839 // in the caller. Also, passing the parameteres avoids having to
   840 // recalculate them in the innermost loop.
   841 bool
   842 G1CollectorPolicy::predict_gc_eff(size_t young_length,
   843                                   size_t so_length,
   844                                   double base_time_with_so_ms,
   845                                   size_t init_free_regions,
   846                                   double target_pause_time_ms,
   847                                   double* ret_gc_eff) {
   848   *ret_gc_eff = 0.0;
   850   if (young_length >= init_free_regions)
   851     // end condition 1: not enough space for the young regions
   852     return false;
   854   double accum_surv_rate_adj = 0.0;
   855   if (so_length > 0)
   856     accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
   857   double accum_surv_rate =
   858     accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
   859   size_t bytes_to_copy =
   860     (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
   861   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
   862   double young_other_time_ms =
   863                        predict_young_other_time_ms(young_length - so_length);
   864   double pause_time_ms =
   865                    base_time_with_so_ms + copy_time_ms + young_other_time_ms;
   867   if (pause_time_ms > target_pause_time_ms)
   868     // end condition 2: over the target pause time
   869     return false;
   871   size_t reclaimed_bytes =
   872     (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
   873   size_t free_bytes =
   874                  (init_free_regions - young_length) * HeapRegion::GrainBytes;
   876   if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes)
   877     // end condition 3: out of to-space (conservatively)
   878     return false;
   880   // success!
   881   double gc_eff = (double) reclaimed_bytes / pause_time_ms;
   882   *ret_gc_eff = gc_eff;
   884   return true;
   885 }
   887 void G1CollectorPolicy::check_prediction_validity() {
   888   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
   890   size_t rs_lengths = _g1->young_list_sampled_rs_lengths();
   891   if (rs_lengths > _rs_lengths_prediction) {
   892     // add 10% to avoid having to recalculate often
   893     size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
   894     calculate_young_list_target_config(rs_lengths_prediction);
   895   }
   896 }
   898 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
   899                                                bool is_tlab,
   900                                                bool* gc_overhead_limit_was_exceeded) {
   901   guarantee(false, "Not using this policy feature yet.");
   902   return NULL;
   903 }
   905 // This method controls how a collector handles one or more
   906 // of its generations being fully allocated.
   907 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
   908                                                        bool is_tlab) {
   909   guarantee(false, "Not using this policy feature yet.");
   910   return NULL;
   911 }
   914 #ifndef PRODUCT
   915 bool G1CollectorPolicy::verify_young_ages() {
   916   HeapRegion* head = _g1->young_list_first_region();
   917   return
   918     verify_young_ages(head, _short_lived_surv_rate_group);
   919   // also call verify_young_ages on any additional surv rate groups
   920 }
   922 bool
   923 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
   924                                      SurvRateGroup *surv_rate_group) {
   925   guarantee( surv_rate_group != NULL, "pre-condition" );
   927   const char* name = surv_rate_group->name();
   928   bool ret = true;
   929   int prev_age = -1;
   931   for (HeapRegion* curr = head;
   932        curr != NULL;
   933        curr = curr->get_next_young_region()) {
   934     SurvRateGroup* group = curr->surv_rate_group();
   935     if (group == NULL && !curr->is_survivor()) {
   936       gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
   937       ret = false;
   938     }
   940     if (surv_rate_group == group) {
   941       int age = curr->age_in_surv_rate_group();
   943       if (age < 0) {
   944         gclog_or_tty->print_cr("## %s: encountered negative age", name);
   945         ret = false;
   946       }
   948       if (age <= prev_age) {
   949         gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
   950                                "(%d, %d)", name, age, prev_age);
   951         ret = false;
   952       }
   953       prev_age = age;
   954     }
   955   }
   957   return ret;
   958 }
   959 #endif // PRODUCT
   961 void G1CollectorPolicy::record_full_collection_start() {
   962   _cur_collection_start_sec = os::elapsedTime();
   963   // Release the future to-space so that it is available for compaction into.
   964   _g1->set_full_collection();
   965 }
   967 void G1CollectorPolicy::record_full_collection_end() {
   968   // Consider this like a collection pause for the purposes of allocation
   969   // since last pause.
   970   double end_sec = os::elapsedTime();
   971   double full_gc_time_sec = end_sec - _cur_collection_start_sec;
   972   double full_gc_time_ms = full_gc_time_sec * 1000.0;
   974   checkpoint_conc_overhead();
   976   _all_full_gc_times_ms->add(full_gc_time_ms);
   978   update_recent_gc_times(end_sec, full_gc_time_sec);
   980   _g1->clear_full_collection();
   982   // "Nuke" the heuristics that control the fully/partially young GC
   983   // transitions and make sure we start with fully young GCs after the
   984   // Full GC.
   985   set_full_young_gcs(true);
   986   _last_full_young_gc = false;
   987   _should_revert_to_full_young_gcs = false;
   988   _should_initiate_conc_mark = false;
   989   _known_garbage_bytes = 0;
   990   _known_garbage_ratio = 0.0;
   991   _in_marking_window = false;
   992   _in_marking_window_im = false;
   994   _short_lived_surv_rate_group->record_scan_only_prefix(0);
   995   _short_lived_surv_rate_group->start_adding_regions();
   996   // also call this on any additional surv rate groups
   998   _prev_region_num_young   = _region_num_young;
   999   _prev_region_num_tenured = _region_num_tenured;
  1001   _free_regions_at_end_of_collection = _g1->free_regions();
  1002   _scan_only_regions_at_end_of_collection = 0;
  1003   calculate_young_list_min_length();
  1004   calculate_young_list_target_config();
  1007 void G1CollectorPolicy::record_pop_compute_rc_start() {
  1008   _pop_compute_rc_start = os::elapsedTime();
  1010 void G1CollectorPolicy::record_pop_compute_rc_end() {
  1011   double ms = (os::elapsedTime() - _pop_compute_rc_start)*1000.0;
  1012   _cur_popular_compute_rc_time_ms = ms;
  1013   _pop_compute_rc_start = 0.0;
  1015 void G1CollectorPolicy::record_pop_evac_start() {
  1016   _pop_evac_start = os::elapsedTime();
  1018 void G1CollectorPolicy::record_pop_evac_end() {
  1019   double ms = (os::elapsedTime() - _pop_evac_start)*1000.0;
  1020   _cur_popular_evac_time_ms = ms;
  1021   _pop_evac_start = 0.0;
  1024 void G1CollectorPolicy::record_before_bytes(size_t bytes) {
  1025   _bytes_in_to_space_before_gc += bytes;
  1028 void G1CollectorPolicy::record_after_bytes(size_t bytes) {
  1029   _bytes_in_to_space_after_gc += bytes;
  1032 void G1CollectorPolicy::record_stop_world_start() {
  1033   _stop_world_start = os::elapsedTime();
  1036 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
  1037                                                       size_t start_used) {
  1038   if (PrintGCDetails) {
  1039     gclog_or_tty->stamp(PrintGCTimeStamps);
  1040     gclog_or_tty->print("[GC pause");
  1041     if (in_young_gc_mode())
  1042       gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
  1045   assert(_g1->used_regions() == _g1->recalculate_used_regions(),
  1046          "sanity");
  1048   double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
  1049   _all_stop_world_times_ms->add(s_w_t_ms);
  1050   _stop_world_start = 0.0;
  1052   _cur_collection_start_sec = start_time_sec;
  1053   _cur_collection_pause_used_at_start_bytes = start_used;
  1054   _cur_collection_pause_used_regions_at_start = _g1->used_regions();
  1055   _pending_cards = _g1->pending_card_num();
  1056   _max_pending_cards = _g1->max_pending_card_num();
  1058   _bytes_in_to_space_before_gc = 0;
  1059   _bytes_in_to_space_after_gc = 0;
  1060   _bytes_in_collection_set_before_gc = 0;
  1062 #ifdef DEBUG
  1063   // initialise these to something well known so that we can spot
  1064   // if they are not set properly
  1066   for (int i = 0; i < _parallel_gc_threads; ++i) {
  1067     _par_last_ext_root_scan_times_ms[i] = -666.0;
  1068     _par_last_mark_stack_scan_times_ms[i] = -666.0;
  1069     _par_last_scan_only_times_ms[i] = -666.0;
  1070     _par_last_scan_only_regions_scanned[i] = -666.0;
  1071     _par_last_update_rs_start_times_ms[i] = -666.0;
  1072     _par_last_update_rs_times_ms[i] = -666.0;
  1073     _par_last_update_rs_processed_buffers[i] = -666.0;
  1074     _par_last_scan_rs_start_times_ms[i] = -666.0;
  1075     _par_last_scan_rs_times_ms[i] = -666.0;
  1076     _par_last_scan_new_refs_times_ms[i] = -666.0;
  1077     _par_last_obj_copy_times_ms[i] = -666.0;
  1078     _par_last_termination_times_ms[i] = -666.0;
  1080     _pop_par_last_update_rs_start_times_ms[i] = -666.0;
  1081     _pop_par_last_update_rs_times_ms[i] = -666.0;
  1082     _pop_par_last_update_rs_processed_buffers[i] = -666.0;
  1083     _pop_par_last_scan_rs_start_times_ms[i] = -666.0;
  1084     _pop_par_last_scan_rs_times_ms[i] = -666.0;
  1085     _pop_par_last_closure_app_times_ms[i] = -666.0;
  1087 #endif
  1089   for (int i = 0; i < _aux_num; ++i) {
  1090     _cur_aux_times_ms[i] = 0.0;
  1091     _cur_aux_times_set[i] = false;
  1094   _satb_drain_time_set = false;
  1095   _last_satb_drain_processed_buffers = -1;
  1097   if (in_young_gc_mode())
  1098     _last_young_gc_full = false;
  1101   // do that for any other surv rate groups
  1102   _short_lived_surv_rate_group->stop_adding_regions();
  1103   size_t short_lived_so_length = _young_list_so_prefix_length;
  1104   _short_lived_surv_rate_group->record_scan_only_prefix(short_lived_so_length);
  1105   tag_scan_only(short_lived_so_length);
  1107   assert( verify_young_ages(), "region age verification" );
  1110 void G1CollectorPolicy::tag_scan_only(size_t short_lived_scan_only_length) {
  1111   // done in a way that it can be extended for other surv rate groups too...
  1113   HeapRegion* head = _g1->young_list_first_region();
  1114   bool finished_short_lived = (short_lived_scan_only_length == 0);
  1116   if (finished_short_lived)
  1117     return;
  1119   for (HeapRegion* curr = head;
  1120        curr != NULL;
  1121        curr = curr->get_next_young_region()) {
  1122     SurvRateGroup* surv_rate_group = curr->surv_rate_group();
  1123     int age = curr->age_in_surv_rate_group();
  1125     if (surv_rate_group == _short_lived_surv_rate_group) {
  1126       if ((size_t)age < short_lived_scan_only_length)
  1127         curr->set_scan_only();
  1128       else
  1129         finished_short_lived = true;
  1133     if (finished_short_lived)
  1134       return;
  1137   guarantee( false, "we should never reach here" );
  1140 void G1CollectorPolicy::record_popular_pause_preamble_start() {
  1141   _cur_popular_preamble_start_ms = os::elapsedTime() * 1000.0;
  1144 void G1CollectorPolicy::record_popular_pause_preamble_end() {
  1145   _cur_popular_preamble_time_ms =
  1146     (os::elapsedTime() * 1000.0) - _cur_popular_preamble_start_ms;
  1148   // copy the recorded statistics of the first pass to temporary arrays
  1149   for (int i = 0; i < _parallel_gc_threads; ++i) {
  1150     _pop_par_last_update_rs_start_times_ms[i] = _par_last_update_rs_start_times_ms[i];
  1151     _pop_par_last_update_rs_times_ms[i] = _par_last_update_rs_times_ms[i];
  1152     _pop_par_last_update_rs_processed_buffers[i] = _par_last_update_rs_processed_buffers[i];
  1153     _pop_par_last_scan_rs_start_times_ms[i] = _par_last_scan_rs_start_times_ms[i];
  1154     _pop_par_last_scan_rs_times_ms[i] = _par_last_scan_rs_times_ms[i];
  1155     _pop_par_last_closure_app_times_ms[i] = _par_last_obj_copy_times_ms[i];
  1159 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
  1160   _mark_closure_time_ms = mark_closure_time_ms;
  1163 void G1CollectorPolicy::record_concurrent_mark_init_start() {
  1164   _mark_init_start_sec = os::elapsedTime();
  1165   guarantee(!in_young_gc_mode(), "should not do be here in young GC mode");
  1168 void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double
  1169                                                    mark_init_elapsed_time_ms) {
  1170   _during_marking = true;
  1171   _should_initiate_conc_mark = false;
  1172   _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
  1175 void G1CollectorPolicy::record_concurrent_mark_init_end() {
  1176   double end_time_sec = os::elapsedTime();
  1177   double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
  1178   _concurrent_mark_init_times_ms->add(elapsed_time_ms);
  1179   checkpoint_conc_overhead();
  1180   record_concurrent_mark_init_end_pre(elapsed_time_ms);
  1182   _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true);
  1185 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
  1186   _mark_remark_start_sec = os::elapsedTime();
  1187   _during_marking = false;
  1190 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
  1191   double end_time_sec = os::elapsedTime();
  1192   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
  1193   checkpoint_conc_overhead();
  1194   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
  1195   _cur_mark_stop_world_time_ms += elapsed_time_ms;
  1196   _prev_collection_pause_end_ms += elapsed_time_ms;
  1198   _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
  1201 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
  1202   _mark_cleanup_start_sec = os::elapsedTime();
  1205 void
  1206 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
  1207                                                       size_t max_live_bytes) {
  1208   record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
  1209   record_concurrent_mark_cleanup_end_work2();
  1212 void
  1213 G1CollectorPolicy::
  1214 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
  1215                                          size_t max_live_bytes) {
  1216   if (_n_marks < 2) _n_marks++;
  1217   if (G1PolicyVerbose > 0)
  1218     gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB "
  1219                            " (of " SIZE_FORMAT " MB heap).",
  1220                            max_live_bytes/M, _g1->capacity()/M);
  1223 // The important thing about this is that it includes "os::elapsedTime".
  1224 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
  1225   checkpoint_conc_overhead();
  1226   double end_time_sec = os::elapsedTime();
  1227   double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
  1228   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
  1229   _cur_mark_stop_world_time_ms += elapsed_time_ms;
  1230   _prev_collection_pause_end_ms += elapsed_time_ms;
  1232   _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
  1234   _num_markings++;
  1236   // We did a marking, so reset the "since_last_mark" variables.
  1237   double considerConcMarkCost = 1.0;
  1238   // If there are available processors, concurrent activity is free...
  1239   if (Threads::number_of_non_daemon_threads() * 2 <
  1240       os::active_processor_count()) {
  1241     considerConcMarkCost = 0.0;
  1243   _n_pauses_at_mark_end = _n_pauses;
  1244   _n_marks_since_last_pause++;
  1245   _conc_mark_initiated = false;
  1248 void
  1249 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
  1250   if (in_young_gc_mode()) {
  1251     _should_revert_to_full_young_gcs = false;
  1252     _last_full_young_gc = true;
  1253     _in_marking_window = false;
  1254     if (adaptive_young_list_length())
  1255       calculate_young_list_target_config();
  1259 void G1CollectorPolicy::record_concurrent_pause() {
  1260   if (_stop_world_start > 0.0) {
  1261     double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
  1262     _all_yield_times_ms->add(yield_ms);
  1266 void G1CollectorPolicy::record_concurrent_pause_end() {
  1269 void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() {
  1270   _cur_CH_strong_roots_end_sec = os::elapsedTime();
  1271   _cur_CH_strong_roots_dur_ms =
  1272     (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0;
  1275 void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() {
  1276   _cur_G1_strong_roots_end_sec = os::elapsedTime();
  1277   _cur_G1_strong_roots_dur_ms =
  1278     (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0;
  1281 template<class T>
  1282 T sum_of(T* sum_arr, int start, int n, int N) {
  1283   T sum = (T)0;
  1284   for (int i = 0; i < n; i++) {
  1285     int j = (start + i) % N;
  1286     sum += sum_arr[j];
  1288   return sum;
  1291 void G1CollectorPolicy::print_par_stats (int level,
  1292                                          const char* str,
  1293                                          double* data,
  1294                                          bool summary) {
  1295   double min = data[0], max = data[0];
  1296   double total = 0.0;
  1297   int j;
  1298   for (j = 0; j < level; ++j)
  1299     gclog_or_tty->print("   ");
  1300   gclog_or_tty->print("[%s (ms):", str);
  1301   for (uint i = 0; i < ParallelGCThreads; ++i) {
  1302     double val = data[i];
  1303     if (val < min)
  1304       min = val;
  1305     if (val > max)
  1306       max = val;
  1307     total += val;
  1308     gclog_or_tty->print("  %3.1lf", val);
  1310   if (summary) {
  1311     gclog_or_tty->print_cr("");
  1312     double avg = total / (double) ParallelGCThreads;
  1313     gclog_or_tty->print(" ");
  1314     for (j = 0; j < level; ++j)
  1315       gclog_or_tty->print("   ");
  1316     gclog_or_tty->print("Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf",
  1317                         avg, min, max);
  1319   gclog_or_tty->print_cr("]");
  1322 void G1CollectorPolicy::print_par_buffers (int level,
  1323                                          const char* str,
  1324                                          double* data,
  1325                                          bool summary) {
  1326   double min = data[0], max = data[0];
  1327   double total = 0.0;
  1328   int j;
  1329   for (j = 0; j < level; ++j)
  1330     gclog_or_tty->print("   ");
  1331   gclog_or_tty->print("[%s :", str);
  1332   for (uint i = 0; i < ParallelGCThreads; ++i) {
  1333     double val = data[i];
  1334     if (val < min)
  1335       min = val;
  1336     if (val > max)
  1337       max = val;
  1338     total += val;
  1339     gclog_or_tty->print(" %d", (int) val);
  1341   if (summary) {
  1342     gclog_or_tty->print_cr("");
  1343     double avg = total / (double) ParallelGCThreads;
  1344     gclog_or_tty->print(" ");
  1345     for (j = 0; j < level; ++j)
  1346       gclog_or_tty->print("   ");
  1347     gclog_or_tty->print("Sum: %d, Avg: %d, Min: %d, Max: %d",
  1348                (int)total, (int)avg, (int)min, (int)max);
  1350   gclog_or_tty->print_cr("]");
  1353 void G1CollectorPolicy::print_stats (int level,
  1354                                      const char* str,
  1355                                      double value) {
  1356   for (int j = 0; j < level; ++j)
  1357     gclog_or_tty->print("   ");
  1358   gclog_or_tty->print_cr("[%s: %5.1lf ms]", str, value);
  1361 void G1CollectorPolicy::print_stats (int level,
  1362                                      const char* str,
  1363                                      int value) {
  1364   for (int j = 0; j < level; ++j)
  1365     gclog_or_tty->print("   ");
  1366   gclog_or_tty->print_cr("[%s: %d]", str, value);
  1369 double G1CollectorPolicy::avg_value (double* data) {
  1370   if (ParallelGCThreads > 0) {
  1371     double ret = 0.0;
  1372     for (uint i = 0; i < ParallelGCThreads; ++i)
  1373       ret += data[i];
  1374     return ret / (double) ParallelGCThreads;
  1375   } else {
  1376     return data[0];
  1380 double G1CollectorPolicy::max_value (double* data) {
  1381   if (ParallelGCThreads > 0) {
  1382     double ret = data[0];
  1383     for (uint i = 1; i < ParallelGCThreads; ++i)
  1384       if (data[i] > ret)
  1385         ret = data[i];
  1386     return ret;
  1387   } else {
  1388     return data[0];
  1392 double G1CollectorPolicy::sum_of_values (double* data) {
  1393   if (ParallelGCThreads > 0) {
  1394     double sum = 0.0;
  1395     for (uint i = 0; i < ParallelGCThreads; i++)
  1396       sum += data[i];
  1397     return sum;
  1398   } else {
  1399     return data[0];
  1403 double G1CollectorPolicy::max_sum (double* data1,
  1404                                    double* data2) {
  1405   double ret = data1[0] + data2[0];
  1407   if (ParallelGCThreads > 0) {
  1408     for (uint i = 1; i < ParallelGCThreads; ++i) {
  1409       double data = data1[i] + data2[i];
  1410       if (data > ret)
  1411         ret = data;
  1414   return ret;
  1417 // Anything below that is considered to be zero
  1418 #define MIN_TIMER_GRANULARITY 0.0000001
  1420 void G1CollectorPolicy::record_collection_pause_end(bool popular,
  1421                                                     bool abandoned) {
  1422   double end_time_sec = os::elapsedTime();
  1423   double elapsed_ms = _last_pause_time_ms;
  1424   bool parallel = ParallelGCThreads > 0;
  1425   double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0;
  1426   size_t rs_size =
  1427     _cur_collection_pause_used_regions_at_start - collection_set_size();
  1428   size_t cur_used_bytes = _g1->used();
  1429   assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
  1430   bool last_pause_included_initial_mark = false;
  1432 #ifndef PRODUCT
  1433   if (G1YoungSurvRateVerbose) {
  1434     gclog_or_tty->print_cr("");
  1435     _short_lived_surv_rate_group->print();
  1436     // do that for any other surv rate groups too
  1438 #endif // PRODUCT
  1440   checkpoint_conc_overhead();
  1442   if (in_young_gc_mode()) {
  1443     last_pause_included_initial_mark = _should_initiate_conc_mark;
  1444     if (last_pause_included_initial_mark)
  1445       record_concurrent_mark_init_end_pre(0.0);
  1447     size_t min_used_targ =
  1448       (_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta);
  1450     if (cur_used_bytes > min_used_targ) {
  1451       if (cur_used_bytes <= _prev_collection_pause_used_at_end_bytes) {
  1452       } else if (!_g1->mark_in_progress() && !_last_full_young_gc) {
  1453         _should_initiate_conc_mark = true;
  1457     _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
  1460   _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
  1461                           end_time_sec, false);
  1463   guarantee(_cur_collection_pause_used_regions_at_start >=
  1464             collection_set_size(),
  1465             "Negative RS size?");
  1467   // This assert is exempted when we're doing parallel collection pauses,
  1468   // because the fragmentation caused by the parallel GC allocation buffers
  1469   // can lead to more memory being used during collection than was used
  1470   // before. Best leave this out until the fragmentation problem is fixed.
  1471   // Pauses in which evacuation failed can also lead to negative
  1472   // collections, since no space is reclaimed from a region containing an
  1473   // object whose evacuation failed.
  1474   // Further, we're now always doing parallel collection.  But I'm still
  1475   // leaving this here as a placeholder for a more precise assertion later.
  1476   // (DLD, 10/05.)
  1477   assert((true || parallel) // Always using GC LABs now.
  1478          || _g1->evacuation_failed()
  1479          || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
  1480          "Negative collection");
  1482   size_t freed_bytes =
  1483     _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
  1484   size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
  1485   double survival_fraction =
  1486     (double)surviving_bytes/
  1487     (double)_collection_set_bytes_used_before;
  1489   _n_pauses++;
  1491   if (!abandoned) {
  1492     _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms);
  1493     _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms);
  1494     _recent_evac_times_ms->add(evac_ms);
  1495     _recent_pause_times_ms->add(elapsed_ms);
  1497     _recent_rs_sizes->add(rs_size);
  1499     // We exempt parallel collection from this check because Alloc Buffer
  1500     // fragmentation can produce negative collections.  Same with evac
  1501     // failure.
  1502     // Further, we're now always doing parallel collection.  But I'm still
  1503     // leaving this here as a placeholder for a more precise assertion later.
  1504     // (DLD, 10/05.
  1505     assert((true || parallel)
  1506            || _g1->evacuation_failed()
  1507            || surviving_bytes <= _collection_set_bytes_used_before,
  1508            "Or else negative collection!");
  1509     _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
  1510     _recent_CS_bytes_surviving->add(surviving_bytes);
  1512     // this is where we update the allocation rate of the application
  1513     double app_time_ms =
  1514       (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
  1515     if (app_time_ms < MIN_TIMER_GRANULARITY) {
  1516       // This usually happens due to the timer not having the required
  1517       // granularity. Some Linuxes are the usual culprits.
  1518       // We'll just set it to something (arbitrarily) small.
  1519       app_time_ms = 1.0;
  1521     size_t regions_allocated =
  1522       (_region_num_young - _prev_region_num_young) +
  1523       (_region_num_tenured - _prev_region_num_tenured);
  1524     double alloc_rate_ms = (double) regions_allocated / app_time_ms;
  1525     _alloc_rate_ms_seq->add(alloc_rate_ms);
  1526     _prev_region_num_young   = _region_num_young;
  1527     _prev_region_num_tenured = _region_num_tenured;
  1529     double interval_ms =
  1530       (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
  1531     update_recent_gc_times(end_time_sec, elapsed_ms);
  1532     _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
  1533     assert(recent_avg_pause_time_ratio() < 1.00, "All GC?");
  1536   if (G1PolicyVerbose > 1) {
  1537     gclog_or_tty->print_cr("   Recording collection pause(%d)", _n_pauses);
  1540   PauseSummary* summary;
  1541   if (!abandoned && !popular)
  1542     summary = _non_pop_summary;
  1543   else if (!abandoned && popular)
  1544     summary = _pop_summary;
  1545   else if (abandoned && !popular)
  1546     summary = _non_pop_abandoned_summary;
  1547   else if (abandoned && popular)
  1548     summary = _pop_abandoned_summary;
  1549   else
  1550     guarantee(false, "should not get here!");
  1552   double pop_update_rs_time;
  1553   double pop_update_rs_processed_buffers;
  1554   double pop_scan_rs_time;
  1555   double pop_closure_app_time;
  1556   double pop_other_time;
  1558   if (popular) {
  1559     PopPreambleSummary* preamble_summary = summary->pop_preamble_summary();
  1560     guarantee(preamble_summary != NULL, "should not be null!");
  1562     pop_update_rs_time = avg_value(_pop_par_last_update_rs_times_ms);
  1563     pop_update_rs_processed_buffers =
  1564       sum_of_values(_pop_par_last_update_rs_processed_buffers);
  1565     pop_scan_rs_time = avg_value(_pop_par_last_scan_rs_times_ms);
  1566     pop_closure_app_time = avg_value(_pop_par_last_closure_app_times_ms);
  1567     pop_other_time = _cur_popular_preamble_time_ms -
  1568       (pop_update_rs_time + pop_scan_rs_time + pop_closure_app_time +
  1569        _cur_popular_evac_time_ms);
  1571     preamble_summary->record_pop_preamble_time_ms(_cur_popular_preamble_time_ms);
  1572     preamble_summary->record_pop_update_rs_time_ms(pop_update_rs_time);
  1573     preamble_summary->record_pop_scan_rs_time_ms(pop_scan_rs_time);
  1574     preamble_summary->record_pop_closure_app_time_ms(pop_closure_app_time);
  1575     preamble_summary->record_pop_evacuation_time_ms(_cur_popular_evac_time_ms);
  1576     preamble_summary->record_pop_other_time_ms(pop_other_time);
  1579   double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
  1580   double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
  1581   double scan_only_time = avg_value(_par_last_scan_only_times_ms);
  1582   double scan_only_regions_scanned =
  1583     sum_of_values(_par_last_scan_only_regions_scanned);
  1584   double update_rs_time = avg_value(_par_last_update_rs_times_ms);
  1585   double update_rs_processed_buffers =
  1586     sum_of_values(_par_last_update_rs_processed_buffers);
  1587   double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
  1588   double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
  1589   double termination_time = avg_value(_par_last_termination_times_ms);
  1591   double parallel_other_time;
  1592   if (!abandoned) {
  1593     MainBodySummary* body_summary = summary->main_body_summary();
  1594     guarantee(body_summary != NULL, "should not be null!");
  1596     if (_satb_drain_time_set)
  1597       body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
  1598     else
  1599       body_summary->record_satb_drain_time_ms(0.0);
  1600     body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
  1601     body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
  1602     body_summary->record_scan_only_time_ms(scan_only_time);
  1603     body_summary->record_update_rs_time_ms(update_rs_time);
  1604     body_summary->record_scan_rs_time_ms(scan_rs_time);
  1605     body_summary->record_obj_copy_time_ms(obj_copy_time);
  1606     if (parallel) {
  1607       body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
  1608       body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
  1609       body_summary->record_termination_time_ms(termination_time);
  1610       parallel_other_time = _cur_collection_par_time_ms -
  1611         (update_rs_time + ext_root_scan_time + mark_stack_scan_time +
  1612          scan_only_time + scan_rs_time + obj_copy_time + termination_time);
  1613       body_summary->record_parallel_other_time_ms(parallel_other_time);
  1615     body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
  1618   if (G1PolicyVerbose > 1) {
  1619     gclog_or_tty->print_cr("      ET: %10.6f ms           (avg: %10.6f ms)\n"
  1620                            "        CH Strong: %10.6f ms    (avg: %10.6f ms)\n"
  1621                            "        G1 Strong: %10.6f ms    (avg: %10.6f ms)\n"
  1622                            "        Evac:      %10.6f ms    (avg: %10.6f ms)\n"
  1623                            "       ET-RS:  %10.6f ms      (avg: %10.6f ms)\n"
  1624                            "      |RS|: " SIZE_FORMAT,
  1625                            elapsed_ms, recent_avg_time_for_pauses_ms(),
  1626                            _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(),
  1627                            _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(),
  1628                            evac_ms, recent_avg_time_for_evac_ms(),
  1629                            scan_rs_time,
  1630                            recent_avg_time_for_pauses_ms() -
  1631                            recent_avg_time_for_G1_strong_ms(),
  1632                            rs_size);
  1634     gclog_or_tty->print_cr("       Used at start: " SIZE_FORMAT"K"
  1635                            "       At end " SIZE_FORMAT "K\n"
  1636                            "       garbage      : " SIZE_FORMAT "K"
  1637                            "       of     " SIZE_FORMAT "K\n"
  1638                            "       survival     : %6.2f%%  (%6.2f%% avg)",
  1639                            _cur_collection_pause_used_at_start_bytes/K,
  1640                            _g1->used()/K, freed_bytes/K,
  1641                            _collection_set_bytes_used_before/K,
  1642                            survival_fraction*100.0,
  1643                            recent_avg_survival_fraction()*100.0);
  1644     gclog_or_tty->print_cr("       Recent %% gc pause time: %6.2f",
  1645                            recent_avg_pause_time_ratio() * 100.0);
  1648   double other_time_ms = elapsed_ms;
  1649   if (popular)
  1650     other_time_ms -= _cur_popular_preamble_time_ms;
  1652   if (!abandoned) {
  1653     if (_satb_drain_time_set)
  1654       other_time_ms -= _cur_satb_drain_time_ms;
  1656     if (parallel)
  1657       other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
  1658     else
  1659       other_time_ms -=
  1660         update_rs_time +
  1661         ext_root_scan_time + mark_stack_scan_time + scan_only_time +
  1662         scan_rs_time + obj_copy_time;
  1665   if (PrintGCDetails) {
  1666     gclog_or_tty->print_cr("%s%s, %1.8lf secs]",
  1667                            (popular && !abandoned) ? " (popular)" :
  1668                            (!popular && abandoned) ? " (abandoned)" :
  1669                            (popular && abandoned) ? " (popular/abandoned)" : "",
  1670                            (last_pause_included_initial_mark) ? " (initial-mark)" : "",
  1671                            elapsed_ms / 1000.0);
  1673     if (!abandoned) {
  1674       if (_satb_drain_time_set)
  1675         print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
  1676       if (_last_satb_drain_processed_buffers >= 0)
  1677         print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
  1679     if (popular)
  1680       print_stats(1, "Popularity Preamble", _cur_popular_preamble_time_ms);
  1681     if (parallel) {
  1682       if (popular) {
  1683         print_par_stats(2, "Update RS (Start)", _pop_par_last_update_rs_start_times_ms, false);
  1684         print_par_stats(2, "Update RS", _pop_par_last_update_rs_times_ms);
  1685         if (G1RSBarrierUseQueue)
  1686           print_par_buffers(3, "Processed Buffers",
  1687                             _pop_par_last_update_rs_processed_buffers, true);
  1688         print_par_stats(2, "Scan RS", _pop_par_last_scan_rs_times_ms);
  1689         print_par_stats(2, "Closure app", _pop_par_last_closure_app_times_ms);
  1690         print_stats(2, "Evacuation", _cur_popular_evac_time_ms);
  1691         print_stats(2, "Other", pop_other_time);
  1693       if (!abandoned) {
  1694         print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
  1695         if (!popular) {
  1696           print_par_stats(2, "Update RS (Start)", _par_last_update_rs_start_times_ms, false);
  1697           print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
  1698           if (G1RSBarrierUseQueue)
  1699             print_par_buffers(3, "Processed Buffers",
  1700                               _par_last_update_rs_processed_buffers, true);
  1702         print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
  1703         print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
  1704         print_par_stats(2, "Scan-Only Scanning", _par_last_scan_only_times_ms);
  1705         print_par_buffers(3, "Scan-Only Regions",
  1706                           _par_last_scan_only_regions_scanned, true);
  1707         print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
  1708         print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
  1709         print_par_stats(2, "Termination", _par_last_termination_times_ms);
  1710         print_stats(2, "Other", parallel_other_time);
  1711         print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
  1713     } else {
  1714       if (popular) {
  1715         print_stats(2, "Update RS", pop_update_rs_time);
  1716         if (G1RSBarrierUseQueue)
  1717           print_stats(3, "Processed Buffers",
  1718                       (int)pop_update_rs_processed_buffers);
  1719         print_stats(2, "Scan RS", pop_scan_rs_time);
  1720         print_stats(2, "Closure App", pop_closure_app_time);
  1721         print_stats(2, "Evacuation", _cur_popular_evac_time_ms);
  1722         print_stats(2, "Other", pop_other_time);
  1724       if (!abandoned) {
  1725         if (!popular) {
  1726           print_stats(1, "Update RS", update_rs_time);
  1727           if (G1RSBarrierUseQueue)
  1728             print_stats(2, "Processed Buffers",
  1729                         (int)update_rs_processed_buffers);
  1731         print_stats(1, "Ext Root Scanning", ext_root_scan_time);
  1732         print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
  1733         print_stats(1, "Scan-Only Scanning", scan_only_time);
  1734         print_stats(1, "Scan RS", scan_rs_time);
  1735         print_stats(1, "Object Copying", obj_copy_time);
  1738     print_stats(1, "Other", other_time_ms);
  1739     for (int i = 0; i < _aux_num; ++i) {
  1740       if (_cur_aux_times_set[i]) {
  1741         char buffer[96];
  1742         sprintf(buffer, "Aux%d", i);
  1743         print_stats(1, buffer, _cur_aux_times_ms[i]);
  1747   if (PrintGCDetails)
  1748     gclog_or_tty->print("   [");
  1749   if (PrintGC || PrintGCDetails)
  1750     _g1->print_size_transition(gclog_or_tty,
  1751                                _cur_collection_pause_used_at_start_bytes,
  1752                                _g1->used(), _g1->capacity());
  1753   if (PrintGCDetails)
  1754     gclog_or_tty->print_cr("]");
  1756   _all_pause_times_ms->add(elapsed_ms);
  1757   summary->record_total_time_ms(elapsed_ms);
  1758   summary->record_other_time_ms(other_time_ms);
  1759   for (int i = 0; i < _aux_num; ++i)
  1760     if (_cur_aux_times_set[i])
  1761       _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
  1763   // Reset marks-between-pauses counter.
  1764   _n_marks_since_last_pause = 0;
  1766   // Update the efficiency-since-mark vars.
  1767   double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
  1768   if (elapsed_ms < MIN_TIMER_GRANULARITY) {
  1769     // This usually happens due to the timer not having the required
  1770     // granularity. Some Linuxes are the usual culprits.
  1771     // We'll just set it to something (arbitrarily) small.
  1772     proc_ms = 1.0;
  1774   double cur_efficiency = (double) freed_bytes / proc_ms;
  1776   bool new_in_marking_window = _in_marking_window;
  1777   bool new_in_marking_window_im = false;
  1778   if (_should_initiate_conc_mark) {
  1779     new_in_marking_window = true;
  1780     new_in_marking_window_im = true;
  1783   if (in_young_gc_mode()) {
  1784     if (_last_full_young_gc) {
  1785       set_full_young_gcs(false);
  1786       _last_full_young_gc = false;
  1789     if ( !_last_young_gc_full ) {
  1790       if ( _should_revert_to_full_young_gcs ||
  1791            _known_garbage_ratio < 0.05 ||
  1792            (adaptive_young_list_length() &&
  1793            (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) {
  1794         set_full_young_gcs(true);
  1797     _should_revert_to_full_young_gcs = false;
  1799     if (_last_young_gc_full && !_during_marking)
  1800       _young_gc_eff_seq->add(cur_efficiency);
  1803   _short_lived_surv_rate_group->start_adding_regions();
  1804   // do that for any other surv rate groupsx
  1806   // <NEW PREDICTION>
  1808   if (!popular && !abandoned) {
  1809     double pause_time_ms = elapsed_ms;
  1811     size_t diff = 0;
  1812     if (_max_pending_cards >= _pending_cards)
  1813       diff = _max_pending_cards - _pending_cards;
  1814     _pending_card_diff_seq->add((double) diff);
  1816     double cost_per_card_ms = 0.0;
  1817     if (_pending_cards > 0) {
  1818       cost_per_card_ms = update_rs_time / (double) _pending_cards;
  1819       _cost_per_card_ms_seq->add(cost_per_card_ms);
  1822     double cost_per_scan_only_region_ms = 0.0;
  1823     if (scan_only_regions_scanned > 0.0) {
  1824       cost_per_scan_only_region_ms =
  1825         scan_only_time / scan_only_regions_scanned;
  1826       if (_in_marking_window_im)
  1827         _cost_per_scan_only_region_ms_during_cm_seq->add(cost_per_scan_only_region_ms);
  1828       else
  1829         _cost_per_scan_only_region_ms_seq->add(cost_per_scan_only_region_ms);
  1832     size_t cards_scanned = _g1->cards_scanned();
  1834     double cost_per_entry_ms = 0.0;
  1835     if (cards_scanned > 10) {
  1836       cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
  1837       if (_last_young_gc_full)
  1838         _cost_per_entry_ms_seq->add(cost_per_entry_ms);
  1839       else
  1840         _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
  1843     if (_max_rs_lengths > 0) {
  1844       double cards_per_entry_ratio =
  1845         (double) cards_scanned / (double) _max_rs_lengths;
  1846       if (_last_young_gc_full)
  1847         _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
  1848       else
  1849         _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
  1852     size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
  1853     if (rs_length_diff >= 0)
  1854       _rs_length_diff_seq->add((double) rs_length_diff);
  1856     size_t copied_bytes = surviving_bytes;
  1857     double cost_per_byte_ms = 0.0;
  1858     if (copied_bytes > 0) {
  1859       cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
  1860       if (_in_marking_window)
  1861         _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
  1862       else
  1863         _cost_per_byte_ms_seq->add(cost_per_byte_ms);
  1866     double all_other_time_ms = pause_time_ms -
  1867       (update_rs_time + scan_only_time + scan_rs_time + obj_copy_time +
  1868        _mark_closure_time_ms + termination_time);
  1870     double young_other_time_ms = 0.0;
  1871     if (_recorded_young_regions > 0) {
  1872       young_other_time_ms =
  1873         _recorded_young_cset_choice_time_ms +
  1874         _recorded_young_free_cset_time_ms;
  1875       _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
  1876                                              (double) _recorded_young_regions);
  1878     double non_young_other_time_ms = 0.0;
  1879     if (_recorded_non_young_regions > 0) {
  1880       non_young_other_time_ms =
  1881         _recorded_non_young_cset_choice_time_ms +
  1882         _recorded_non_young_free_cset_time_ms;
  1884       _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
  1885                                          (double) _recorded_non_young_regions);
  1888     double constant_other_time_ms = all_other_time_ms -
  1889       (young_other_time_ms + non_young_other_time_ms);
  1890     _constant_other_time_ms_seq->add(constant_other_time_ms);
  1892     double survival_ratio = 0.0;
  1893     if (_bytes_in_collection_set_before_gc > 0) {
  1894       survival_ratio = (double) bytes_in_to_space_during_gc() /
  1895         (double) _bytes_in_collection_set_before_gc;
  1898     _pending_cards_seq->add((double) _pending_cards);
  1899     _scanned_cards_seq->add((double) cards_scanned);
  1900     _rs_lengths_seq->add((double) _max_rs_lengths);
  1902     double expensive_region_limit_ms =
  1903       (double) G1MaxPauseTimeMS - predict_constant_other_time_ms();
  1904     if (expensive_region_limit_ms < 0.0) {
  1905       // this means that the other time was predicted to be longer than
  1906       // than the max pause time
  1907       expensive_region_limit_ms = (double) G1MaxPauseTimeMS;
  1909     _expensive_region_limit_ms = expensive_region_limit_ms;
  1911     if (PREDICTIONS_VERBOSE) {
  1912       gclog_or_tty->print_cr("");
  1913       gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
  1914                     "REGIONS %d %d %d %d "
  1915                     "PENDING_CARDS %d %d "
  1916                     "CARDS_SCANNED %d %d "
  1917                     "RS_LENGTHS %d %d "
  1918                     "SCAN_ONLY_SCAN %1.6lf %1.6lf "
  1919                     "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
  1920                     "SURVIVAL_RATIO %1.6lf %1.6lf "
  1921                     "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
  1922                     "OTHER_YOUNG %1.6lf %1.6lf "
  1923                     "OTHER_NON_YOUNG %1.6lf %1.6lf "
  1924                     "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
  1925                     "ELAPSED %1.6lf %1.6lf ",
  1926                     _cur_collection_start_sec,
  1927                     (!_last_young_gc_full) ? 2 :
  1928                     (last_pause_included_initial_mark) ? 1 : 0,
  1929                     _recorded_region_num,
  1930                     _recorded_young_regions,
  1931                     _recorded_scan_only_regions,
  1932                     _recorded_non_young_regions,
  1933                     _predicted_pending_cards, _pending_cards,
  1934                     _predicted_cards_scanned, cards_scanned,
  1935                     _predicted_rs_lengths, _max_rs_lengths,
  1936                     _predicted_scan_only_scan_time_ms, scan_only_time,
  1937                     _predicted_rs_update_time_ms, update_rs_time,
  1938                     _predicted_rs_scan_time_ms, scan_rs_time,
  1939                     _predicted_survival_ratio, survival_ratio,
  1940                     _predicted_object_copy_time_ms, obj_copy_time,
  1941                     _predicted_constant_other_time_ms, constant_other_time_ms,
  1942                     _predicted_young_other_time_ms, young_other_time_ms,
  1943                     _predicted_non_young_other_time_ms,
  1944                     non_young_other_time_ms,
  1945                     _vtime_diff_ms, termination_time,
  1946                     _predicted_pause_time_ms, elapsed_ms);
  1949     if (G1PolicyVerbose > 0) {
  1950       gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
  1951                     _predicted_pause_time_ms,
  1952                     (_within_target) ? "within" : "outside",
  1953                     elapsed_ms);
  1958   _in_marking_window = new_in_marking_window;
  1959   _in_marking_window_im = new_in_marking_window_im;
  1960   _free_regions_at_end_of_collection = _g1->free_regions();
  1961   _scan_only_regions_at_end_of_collection = _g1->young_list_length();
  1962   calculate_young_list_min_length();
  1963   calculate_young_list_target_config();
  1965   // </NEW PREDICTION>
  1967   _target_pause_time_ms = -1.0;
  1969   // TODO: calculate tenuring threshold
  1970   _tenuring_threshold = MaxTenuringThreshold;
  1973 // <NEW PREDICTION>
  1975 double
  1976 G1CollectorPolicy::
  1977 predict_young_collection_elapsed_time_ms(size_t adjustment) {
  1978   guarantee( adjustment == 0 || adjustment == 1, "invariant" );
  1980   G1CollectedHeap* g1h = G1CollectedHeap::heap();
  1981   size_t young_num = g1h->young_list_length();
  1982   if (young_num == 0)
  1983     return 0.0;
  1985   young_num += adjustment;
  1986   size_t pending_cards = predict_pending_cards();
  1987   size_t rs_lengths = g1h->young_list_sampled_rs_lengths() +
  1988                       predict_rs_length_diff();
  1989   size_t card_num;
  1990   if (full_young_gcs())
  1991     card_num = predict_young_card_num(rs_lengths);
  1992   else
  1993     card_num = predict_non_young_card_num(rs_lengths);
  1994   size_t young_byte_size = young_num * HeapRegion::GrainBytes;
  1995   double accum_yg_surv_rate =
  1996     _short_lived_surv_rate_group->accum_surv_rate(adjustment);
  1998   size_t bytes_to_copy =
  1999     (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
  2001   return
  2002     predict_rs_update_time_ms(pending_cards) +
  2003     predict_rs_scan_time_ms(card_num) +
  2004     predict_object_copy_time_ms(bytes_to_copy) +
  2005     predict_young_other_time_ms(young_num) +
  2006     predict_constant_other_time_ms();
  2009 double
  2010 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
  2011   size_t rs_length = predict_rs_length_diff();
  2012   size_t card_num;
  2013   if (full_young_gcs())
  2014     card_num = predict_young_card_num(rs_length);
  2015   else
  2016     card_num = predict_non_young_card_num(rs_length);
  2017   return predict_base_elapsed_time_ms(pending_cards, card_num);
  2020 double
  2021 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
  2022                                                 size_t scanned_cards) {
  2023   return
  2024     predict_rs_update_time_ms(pending_cards) +
  2025     predict_rs_scan_time_ms(scanned_cards) +
  2026     predict_constant_other_time_ms();
  2029 double
  2030 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
  2031                                                   bool young) {
  2032   size_t rs_length = hr->rem_set()->occupied();
  2033   size_t card_num;
  2034   if (full_young_gcs())
  2035     card_num = predict_young_card_num(rs_length);
  2036   else
  2037     card_num = predict_non_young_card_num(rs_length);
  2038   size_t bytes_to_copy = predict_bytes_to_copy(hr);
  2040   double region_elapsed_time_ms =
  2041     predict_rs_scan_time_ms(card_num) +
  2042     predict_object_copy_time_ms(bytes_to_copy);
  2044   if (young)
  2045     region_elapsed_time_ms += predict_young_other_time_ms(1);
  2046   else
  2047     region_elapsed_time_ms += predict_non_young_other_time_ms(1);
  2049   return region_elapsed_time_ms;
  2052 size_t
  2053 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
  2054   size_t bytes_to_copy;
  2055   if (hr->is_marked())
  2056     bytes_to_copy = hr->max_live_bytes();
  2057   else {
  2058     guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
  2059                "invariant" );
  2060     int age = hr->age_in_surv_rate_group();
  2061     double yg_surv_rate = predict_yg_surv_rate(age);
  2062     bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
  2065   return bytes_to_copy;
  2068 void
  2069 G1CollectorPolicy::start_recording_regions() {
  2070   _recorded_rs_lengths            = 0;
  2071   _recorded_scan_only_regions     = 0;
  2072   _recorded_young_regions         = 0;
  2073   _recorded_non_young_regions     = 0;
  2075 #if PREDICTIONS_VERBOSE
  2076   _predicted_rs_lengths           = 0;
  2077   _predicted_cards_scanned        = 0;
  2079   _recorded_marked_bytes          = 0;
  2080   _recorded_young_bytes           = 0;
  2081   _predicted_bytes_to_copy        = 0;
  2082 #endif // PREDICTIONS_VERBOSE
  2085 void
  2086 G1CollectorPolicy::record_cset_region(HeapRegion* hr, bool young) {
  2087   if (young) {
  2088     ++_recorded_young_regions;
  2089   } else {
  2090     ++_recorded_non_young_regions;
  2092 #if PREDICTIONS_VERBOSE
  2093   if (young) {
  2094     _recorded_young_bytes += hr->asSpace()->used();
  2095   } else {
  2096     _recorded_marked_bytes += hr->max_live_bytes();
  2098   _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
  2099 #endif // PREDICTIONS_VERBOSE
  2101   size_t rs_length = hr->rem_set()->occupied();
  2102   _recorded_rs_lengths += rs_length;
  2105 void
  2106 G1CollectorPolicy::record_scan_only_regions(size_t scan_only_length) {
  2107   _recorded_scan_only_regions = scan_only_length;
  2110 void
  2111 G1CollectorPolicy::end_recording_regions() {
  2112 #if PREDICTIONS_VERBOSE
  2113   _predicted_pending_cards = predict_pending_cards();
  2114   _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
  2115   if (full_young_gcs())
  2116     _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
  2117   else
  2118     _predicted_cards_scanned +=
  2119       predict_non_young_card_num(_predicted_rs_lengths);
  2120   _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
  2122   _predicted_young_survival_ratio = 0.0;
  2123   for (int i = 0; i < _recorded_young_regions; ++i)
  2124     _predicted_young_survival_ratio += predict_yg_surv_rate(i);
  2125   _predicted_young_survival_ratio /= (double) _recorded_young_regions;
  2127   _predicted_scan_only_scan_time_ms =
  2128     predict_scan_only_time_ms(_recorded_scan_only_regions);
  2129   _predicted_rs_update_time_ms =
  2130     predict_rs_update_time_ms(_g1->pending_card_num());
  2131   _predicted_rs_scan_time_ms =
  2132     predict_rs_scan_time_ms(_predicted_cards_scanned);
  2133   _predicted_object_copy_time_ms =
  2134     predict_object_copy_time_ms(_predicted_bytes_to_copy);
  2135   _predicted_constant_other_time_ms =
  2136     predict_constant_other_time_ms();
  2137   _predicted_young_other_time_ms =
  2138     predict_young_other_time_ms(_recorded_young_regions);
  2139   _predicted_non_young_other_time_ms =
  2140     predict_non_young_other_time_ms(_recorded_non_young_regions);
  2142   _predicted_pause_time_ms =
  2143     _predicted_scan_only_scan_time_ms +
  2144     _predicted_rs_update_time_ms +
  2145     _predicted_rs_scan_time_ms +
  2146     _predicted_object_copy_time_ms +
  2147     _predicted_constant_other_time_ms +
  2148     _predicted_young_other_time_ms +
  2149     _predicted_non_young_other_time_ms;
  2150 #endif // PREDICTIONS_VERBOSE
  2153 void G1CollectorPolicy::check_if_region_is_too_expensive(double
  2154                                                            predicted_time_ms) {
  2155   // I don't think we need to do this when in young GC mode since
  2156   // marking will be initiated next time we hit the soft limit anyway...
  2157   if (predicted_time_ms > _expensive_region_limit_ms) {
  2158     if (!in_young_gc_mode()) {
  2159         set_full_young_gcs(true);
  2160       _should_initiate_conc_mark = true;
  2161     } else
  2162       // no point in doing another partial one
  2163       _should_revert_to_full_young_gcs = true;
  2167 // </NEW PREDICTION>
  2170 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
  2171                                                double elapsed_ms) {
  2172   _recent_gc_times_ms->add(elapsed_ms);
  2173   _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
  2174   _prev_collection_pause_end_ms = end_time_sec * 1000.0;
  2177 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
  2178   if (_recent_pause_times_ms->num() == 0) return (double) G1MaxPauseTimeMS;
  2179   else return _recent_pause_times_ms->avg();
  2182 double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() {
  2183   if (_recent_CH_strong_roots_times_ms->num() == 0)
  2184     return (double)G1MaxPauseTimeMS/3.0;
  2185   else return _recent_CH_strong_roots_times_ms->avg();
  2188 double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() {
  2189   if (_recent_G1_strong_roots_times_ms->num() == 0)
  2190     return (double)G1MaxPauseTimeMS/3.0;
  2191   else return _recent_G1_strong_roots_times_ms->avg();
  2194 double G1CollectorPolicy::recent_avg_time_for_evac_ms() {
  2195   if (_recent_evac_times_ms->num() == 0) return (double)G1MaxPauseTimeMS/3.0;
  2196   else return _recent_evac_times_ms->avg();
  2199 int G1CollectorPolicy::number_of_recent_gcs() {
  2200   assert(_recent_CH_strong_roots_times_ms->num() ==
  2201          _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync");
  2202   assert(_recent_G1_strong_roots_times_ms->num() ==
  2203          _recent_evac_times_ms->num(), "Sequence out of sync");
  2204   assert(_recent_evac_times_ms->num() ==
  2205          _recent_pause_times_ms->num(), "Sequence out of sync");
  2206   assert(_recent_pause_times_ms->num() ==
  2207          _recent_CS_bytes_used_before->num(), "Sequence out of sync");
  2208   assert(_recent_CS_bytes_used_before->num() ==
  2209          _recent_CS_bytes_surviving->num(), "Sequence out of sync");
  2210   return _recent_pause_times_ms->num();
  2213 double G1CollectorPolicy::recent_avg_survival_fraction() {
  2214   return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
  2215                                            _recent_CS_bytes_used_before);
  2218 double G1CollectorPolicy::last_survival_fraction() {
  2219   return last_survival_fraction_work(_recent_CS_bytes_surviving,
  2220                                      _recent_CS_bytes_used_before);
  2223 double
  2224 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
  2225                                                      TruncatedSeq* before) {
  2226   assert(surviving->num() == before->num(), "Sequence out of sync");
  2227   if (before->sum() > 0.0) {
  2228       double recent_survival_rate = surviving->sum() / before->sum();
  2229       // We exempt parallel collection from this check because Alloc Buffer
  2230       // fragmentation can produce negative collections.
  2231       // Further, we're now always doing parallel collection.  But I'm still
  2232       // leaving this here as a placeholder for a more precise assertion later.
  2233       // (DLD, 10/05.)
  2234       assert((true || ParallelGCThreads > 0) ||
  2235              _g1->evacuation_failed() ||
  2236              recent_survival_rate <= 1.0, "Or bad frac");
  2237       return recent_survival_rate;
  2238   } else {
  2239     return 1.0; // Be conservative.
  2243 double
  2244 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
  2245                                                TruncatedSeq* before) {
  2246   assert(surviving->num() == before->num(), "Sequence out of sync");
  2247   if (surviving->num() > 0 && before->last() > 0.0) {
  2248     double last_survival_rate = surviving->last() / before->last();
  2249     // We exempt parallel collection from this check because Alloc Buffer
  2250     // fragmentation can produce negative collections.
  2251     // Further, we're now always doing parallel collection.  But I'm still
  2252     // leaving this here as a placeholder for a more precise assertion later.
  2253     // (DLD, 10/05.)
  2254     assert((true || ParallelGCThreads > 0) ||
  2255            last_survival_rate <= 1.0, "Or bad frac");
  2256     return last_survival_rate;
  2257   } else {
  2258     return 1.0;
  2262 static const int survival_min_obs = 5;
  2263 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
  2264 static const double min_survival_rate = 0.1;
  2266 double
  2267 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
  2268                                                            double latest) {
  2269   double res = avg;
  2270   if (number_of_recent_gcs() < survival_min_obs) {
  2271     res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
  2273   res = MAX2(res, latest);
  2274   res = MAX2(res, min_survival_rate);
  2275   // In the parallel case, LAB fragmentation can produce "negative
  2276   // collections"; so can evac failure.  Cap at 1.0
  2277   res = MIN2(res, 1.0);
  2278   return res;
  2281 size_t G1CollectorPolicy::expansion_amount() {
  2282   if ((int)(recent_avg_pause_time_ratio() * 100.0) > G1GCPct) {
  2283     // We will double the existing space, or take G1ExpandByPctOfAvail % of
  2284     // the available expansion space, whichever is smaller, bounded below
  2285     // by a minimum expansion (unless that's all that's left.)
  2286     const size_t min_expand_bytes = 1*M;
  2287     size_t reserved_bytes = _g1->g1_reserved_obj_bytes();
  2288     size_t committed_bytes = _g1->capacity();
  2289     size_t uncommitted_bytes = reserved_bytes - committed_bytes;
  2290     size_t expand_bytes;
  2291     size_t expand_bytes_via_pct =
  2292       uncommitted_bytes * G1ExpandByPctOfAvail / 100;
  2293     expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
  2294     expand_bytes = MAX2(expand_bytes, min_expand_bytes);
  2295     expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
  2296     if (G1PolicyVerbose > 1) {
  2297       gclog_or_tty->print("Decided to expand: ratio = %5.2f, "
  2298                  "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n"
  2299                  "                   Answer = %d.\n",
  2300                  recent_avg_pause_time_ratio(),
  2301                  byte_size_in_proper_unit(committed_bytes),
  2302                  proper_unit_for_byte_size(committed_bytes),
  2303                  byte_size_in_proper_unit(uncommitted_bytes),
  2304                  proper_unit_for_byte_size(uncommitted_bytes),
  2305                  byte_size_in_proper_unit(expand_bytes_via_pct),
  2306                  proper_unit_for_byte_size(expand_bytes_via_pct),
  2307                  byte_size_in_proper_unit(expand_bytes),
  2308                  proper_unit_for_byte_size(expand_bytes));
  2310     return expand_bytes;
  2311   } else {
  2312     return 0;
  2316 void G1CollectorPolicy::note_start_of_mark_thread() {
  2317   _mark_thread_startup_sec = os::elapsedTime();
  2320 class CountCSClosure: public HeapRegionClosure {
  2321   G1CollectorPolicy* _g1_policy;
  2322 public:
  2323   CountCSClosure(G1CollectorPolicy* g1_policy) :
  2324     _g1_policy(g1_policy) {}
  2325   bool doHeapRegion(HeapRegion* r) {
  2326     _g1_policy->_bytes_in_collection_set_before_gc += r->used();
  2327     return false;
  2329 };
  2331 void G1CollectorPolicy::count_CS_bytes_used() {
  2332   CountCSClosure cs_closure(this);
  2333   _g1->collection_set_iterate(&cs_closure);
  2336 static void print_indent(int level) {
  2337   for (int j = 0; j < level+1; ++j)
  2338     gclog_or_tty->print("   ");
  2341 void G1CollectorPolicy::print_summary (int level,
  2342                                        const char* str,
  2343                                        NumberSeq* seq) const {
  2344   double sum = seq->sum();
  2345   print_indent(level);
  2346   gclog_or_tty->print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
  2347                 str, sum / 1000.0, seq->avg());
  2350 void G1CollectorPolicy::print_summary_sd (int level,
  2351                                           const char* str,
  2352                                           NumberSeq* seq) const {
  2353   print_summary(level, str, seq);
  2354   print_indent(level + 5);
  2355   gclog_or_tty->print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
  2356                 seq->num(), seq->sd(), seq->maximum());
  2359 void G1CollectorPolicy::check_other_times(int level,
  2360                                         NumberSeq* other_times_ms,
  2361                                         NumberSeq* calc_other_times_ms) const {
  2362   bool should_print = false;
  2364   double max_sum = MAX2(fabs(other_times_ms->sum()),
  2365                         fabs(calc_other_times_ms->sum()));
  2366   double min_sum = MIN2(fabs(other_times_ms->sum()),
  2367                         fabs(calc_other_times_ms->sum()));
  2368   double sum_ratio = max_sum / min_sum;
  2369   if (sum_ratio > 1.1) {
  2370     should_print = true;
  2371     print_indent(level + 1);
  2372     gclog_or_tty->print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
  2375   double max_avg = MAX2(fabs(other_times_ms->avg()),
  2376                         fabs(calc_other_times_ms->avg()));
  2377   double min_avg = MIN2(fabs(other_times_ms->avg()),
  2378                         fabs(calc_other_times_ms->avg()));
  2379   double avg_ratio = max_avg / min_avg;
  2380   if (avg_ratio > 1.1) {
  2381     should_print = true;
  2382     print_indent(level + 1);
  2383     gclog_or_tty->print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
  2386   if (other_times_ms->sum() < -0.01) {
  2387     print_indent(level + 1);
  2388     gclog_or_tty->print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
  2391   if (other_times_ms->avg() < -0.01) {
  2392     print_indent(level + 1);
  2393     gclog_or_tty->print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
  2396   if (calc_other_times_ms->sum() < -0.01) {
  2397     should_print = true;
  2398     print_indent(level + 1);
  2399     gclog_or_tty->print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
  2402   if (calc_other_times_ms->avg() < -0.01) {
  2403     should_print = true;
  2404     print_indent(level + 1);
  2405     gclog_or_tty->print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
  2408   if (should_print)
  2409     print_summary(level, "Other(Calc)", calc_other_times_ms);
  2412 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
  2413   bool parallel = ParallelGCThreads > 0;
  2414   MainBodySummary*    body_summary = summary->main_body_summary();
  2415   PopPreambleSummary* preamble_summary = summary->pop_preamble_summary();
  2417   if (summary->get_total_seq()->num() > 0) {
  2418     print_summary_sd(0,
  2419                      (preamble_summary == NULL) ? "Non-Popular Pauses" :
  2420                      "Popular Pauses",
  2421                      summary->get_total_seq());
  2422     if (preamble_summary != NULL) {
  2423       print_summary(1, "Popularity Preamble",
  2424                     preamble_summary->get_pop_preamble_seq());
  2425       print_summary(2, "Update RS", preamble_summary->get_pop_update_rs_seq());
  2426       print_summary(2, "Scan RS", preamble_summary->get_pop_scan_rs_seq());
  2427       print_summary(2, "Closure App",
  2428                     preamble_summary->get_pop_closure_app_seq());
  2429       print_summary(2, "Evacuation",
  2430                     preamble_summary->get_pop_evacuation_seq());
  2431       print_summary(2, "Other", preamble_summary->get_pop_other_seq());
  2433         NumberSeq* other_parts[] = {
  2434           preamble_summary->get_pop_update_rs_seq(),
  2435           preamble_summary->get_pop_scan_rs_seq(),
  2436           preamble_summary->get_pop_closure_app_seq(),
  2437           preamble_summary->get_pop_evacuation_seq()
  2438         };
  2439         NumberSeq calc_other_times_ms(preamble_summary->get_pop_preamble_seq(),
  2440                                       4, other_parts);
  2441         check_other_times(2, preamble_summary->get_pop_other_seq(),
  2442                           &calc_other_times_ms);
  2445     if (body_summary != NULL) {
  2446       print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
  2447       if (parallel) {
  2448         print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
  2449         print_summary(2, "Update RS", body_summary->get_update_rs_seq());
  2450         print_summary(2, "Ext Root Scanning",
  2451                       body_summary->get_ext_root_scan_seq());
  2452         print_summary(2, "Mark Stack Scanning",
  2453                       body_summary->get_mark_stack_scan_seq());
  2454         print_summary(2, "Scan-Only Scanning",
  2455                       body_summary->get_scan_only_seq());
  2456         print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
  2457         print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
  2458         print_summary(2, "Termination", body_summary->get_termination_seq());
  2459         print_summary(2, "Other", body_summary->get_parallel_other_seq());
  2461           NumberSeq* other_parts[] = {
  2462             body_summary->get_update_rs_seq(),
  2463             body_summary->get_ext_root_scan_seq(),
  2464             body_summary->get_mark_stack_scan_seq(),
  2465             body_summary->get_scan_only_seq(),
  2466             body_summary->get_scan_rs_seq(),
  2467             body_summary->get_obj_copy_seq(),
  2468             body_summary->get_termination_seq()
  2469           };
  2470           NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
  2471                                         7, other_parts);
  2472           check_other_times(2, body_summary->get_parallel_other_seq(),
  2473                             &calc_other_times_ms);
  2475         print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
  2476         print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
  2477       } else {
  2478         print_summary(1, "Update RS", body_summary->get_update_rs_seq());
  2479         print_summary(1, "Ext Root Scanning",
  2480                       body_summary->get_ext_root_scan_seq());
  2481         print_summary(1, "Mark Stack Scanning",
  2482                       body_summary->get_mark_stack_scan_seq());
  2483         print_summary(1, "Scan-Only Scanning",
  2484                       body_summary->get_scan_only_seq());
  2485         print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
  2486         print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
  2489     print_summary(1, "Other", summary->get_other_seq());
  2491       NumberSeq calc_other_times_ms;
  2492       if (body_summary != NULL) {
  2493         // not abandoned
  2494         if (parallel) {
  2495           // parallel
  2496           NumberSeq* other_parts[] = {
  2497             body_summary->get_satb_drain_seq(),
  2498             (preamble_summary == NULL) ? NULL :
  2499               preamble_summary->get_pop_preamble_seq(),
  2500             body_summary->get_parallel_seq(),
  2501             body_summary->get_clear_ct_seq()
  2502           };
  2503           calc_other_times_ms = NumberSeq (summary->get_total_seq(),
  2504                                           4, other_parts);
  2505         } else {
  2506           // serial
  2507           NumberSeq* other_parts[] = {
  2508             body_summary->get_satb_drain_seq(),
  2509             (preamble_summary == NULL) ? NULL :
  2510               preamble_summary->get_pop_preamble_seq(),
  2511             body_summary->get_update_rs_seq(),
  2512             body_summary->get_ext_root_scan_seq(),
  2513             body_summary->get_mark_stack_scan_seq(),
  2514             body_summary->get_scan_only_seq(),
  2515             body_summary->get_scan_rs_seq(),
  2516             body_summary->get_obj_copy_seq()
  2517           };
  2518           calc_other_times_ms = NumberSeq(summary->get_total_seq(),
  2519                                           8, other_parts);
  2521       } else {
  2522         // abandoned
  2523         NumberSeq* other_parts[] = {
  2524           (preamble_summary == NULL) ? NULL :
  2525             preamble_summary->get_pop_preamble_seq()
  2526         };
  2527         calc_other_times_ms = NumberSeq(summary->get_total_seq(),
  2528                                         1, other_parts);
  2530       check_other_times(1,  summary->get_other_seq(), &calc_other_times_ms);
  2532   } else {
  2533     print_indent(0);
  2534     gclog_or_tty->print_cr("none");
  2536   gclog_or_tty->print_cr("");
  2539 void
  2540 G1CollectorPolicy::print_abandoned_summary(PauseSummary* non_pop_summary,
  2541                                            PauseSummary* pop_summary) const {
  2542   bool printed = false;
  2543   if (non_pop_summary->get_total_seq()->num() > 0) {
  2544     printed = true;
  2545     print_summary(non_pop_summary);
  2547   if (pop_summary->get_total_seq()->num() > 0) {
  2548     printed = true;
  2549     print_summary(pop_summary);
  2552   if (!printed) {
  2553     print_indent(0);
  2554     gclog_or_tty->print_cr("none");
  2555     gclog_or_tty->print_cr("");
  2559 void G1CollectorPolicy::print_tracing_info() const {
  2560   if (TraceGen0Time) {
  2561     gclog_or_tty->print_cr("ALL PAUSES");
  2562     print_summary_sd(0, "Total", _all_pause_times_ms);
  2563     gclog_or_tty->print_cr("");
  2564     gclog_or_tty->print_cr("");
  2565     gclog_or_tty->print_cr("   Full Young GC Pauses:    %8d", _full_young_pause_num);
  2566     gclog_or_tty->print_cr("   Partial Young GC Pauses: %8d", _partial_young_pause_num);
  2567     gclog_or_tty->print_cr("");
  2569     gclog_or_tty->print_cr("NON-POPULAR PAUSES");
  2570     print_summary(_non_pop_summary);
  2572     gclog_or_tty->print_cr("POPULAR PAUSES");
  2573     print_summary(_pop_summary);
  2575     gclog_or_tty->print_cr("ABANDONED PAUSES");
  2576     print_abandoned_summary(_non_pop_abandoned_summary,
  2577                             _pop_abandoned_summary);
  2579     gclog_or_tty->print_cr("MISC");
  2580     print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
  2581     print_summary_sd(0, "Yields", _all_yield_times_ms);
  2582     for (int i = 0; i < _aux_num; ++i) {
  2583       if (_all_aux_times_ms[i].num() > 0) {
  2584         char buffer[96];
  2585         sprintf(buffer, "Aux%d", i);
  2586         print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
  2590     size_t all_region_num = _region_num_young + _region_num_tenured;
  2591     gclog_or_tty->print_cr("   New Regions %8d, Young %8d (%6.2lf%%), "
  2592                "Tenured %8d (%6.2lf%%)",
  2593                all_region_num,
  2594                _region_num_young,
  2595                (double) _region_num_young / (double) all_region_num * 100.0,
  2596                _region_num_tenured,
  2597                (double) _region_num_tenured / (double) all_region_num * 100.0);
  2599     if (!G1RSBarrierUseQueue) {
  2600       gclog_or_tty->print_cr("Of %d times conc refinement was enabled, %d (%7.2f%%) "
  2601                     "did zero traversals.",
  2602                     _conc_refine_enabled, _conc_refine_zero_traversals,
  2603                     _conc_refine_enabled > 0 ?
  2604                     100.0 * (float)_conc_refine_zero_traversals/
  2605                     (float)_conc_refine_enabled : 0.0);
  2606       gclog_or_tty->print_cr("  Max # of traversals = %d.",
  2607                     _conc_refine_max_traversals);
  2608       gclog_or_tty->print_cr("");
  2611   if (TraceGen1Time) {
  2612     if (_all_full_gc_times_ms->num() > 0) {
  2613       gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
  2614                  _all_full_gc_times_ms->num(),
  2615                  _all_full_gc_times_ms->sum() / 1000.0);
  2616       gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
  2617       gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
  2618                     _all_full_gc_times_ms->sd(),
  2619                     _all_full_gc_times_ms->maximum());
  2624 void G1CollectorPolicy::print_yg_surv_rate_info() const {
  2625 #ifndef PRODUCT
  2626   _short_lived_surv_rate_group->print_surv_rate_summary();
  2627   // add this call for any other surv rate groups
  2628 #endif // PRODUCT
  2631 void G1CollectorPolicy::update_conc_refine_data() {
  2632   unsigned traversals = _g1->concurrent_g1_refine()->disable();
  2633   if (traversals == 0) _conc_refine_zero_traversals++;
  2634   _conc_refine_max_traversals = MAX2(_conc_refine_max_traversals,
  2635                                      (size_t)traversals);
  2637   if (G1PolicyVerbose > 1)
  2638     gclog_or_tty->print_cr("Did a CR traversal series: %d traversals.", traversals);
  2639   double multiplier = 1.0;
  2640   if (traversals == 0) {
  2641     multiplier = 4.0;
  2642   } else if (traversals > (size_t)G1ConcRefineTargTraversals) {
  2643     multiplier = 1.0/1.5;
  2644   } else if (traversals < (size_t)G1ConcRefineTargTraversals) {
  2645     multiplier = 1.5;
  2647   if (G1PolicyVerbose > 1) {
  2648     gclog_or_tty->print_cr("  Multiplier = %7.2f.", multiplier);
  2649     gclog_or_tty->print("  Delta went from %d regions to ",
  2650                _conc_refine_current_delta);
  2652   _conc_refine_current_delta =
  2653     MIN2(_g1->n_regions(),
  2654          (size_t)(_conc_refine_current_delta * multiplier));
  2655   _conc_refine_current_delta =
  2656     MAX2(_conc_refine_current_delta, (size_t)1);
  2657   if (G1PolicyVerbose > 1) {
  2658     gclog_or_tty->print_cr("%d regions.", _conc_refine_current_delta);
  2660   _conc_refine_enabled++;
  2663 void G1CollectorPolicy::set_single_region_collection_set(HeapRegion* hr) {
  2664   assert(collection_set() == NULL, "Must be no current CS.");
  2665   _collection_set_size = 0;
  2666   _collection_set_bytes_used_before = 0;
  2667   add_to_collection_set(hr);
  2668   count_CS_bytes_used();
  2671 bool
  2672 G1CollectorPolicy::should_add_next_region_to_young_list() {
  2673   assert(in_young_gc_mode(), "should be in young GC mode");
  2674   bool ret;
  2675   size_t young_list_length = _g1->young_list_length();
  2677   if (young_list_length < _young_list_target_length) {
  2678     ret = true;
  2679     ++_region_num_young;
  2680   } else {
  2681     ret = false;
  2682     ++_region_num_tenured;
  2685   return ret;
  2688 #ifndef PRODUCT
  2689 // for debugging, bit of a hack...
  2690 static char*
  2691 region_num_to_mbs(int length) {
  2692   static char buffer[64];
  2693   double bytes = (double) (length * HeapRegion::GrainBytes);
  2694   double mbs = bytes / (double) (1024 * 1024);
  2695   sprintf(buffer, "%7.2lfMB", mbs);
  2696   return buffer;
  2698 #endif // PRODUCT
  2700 void
  2701 G1CollectorPolicy::checkpoint_conc_overhead() {
  2702   double conc_overhead = 0.0;
  2703   if (G1AccountConcurrentOverhead)
  2704     conc_overhead = COTracker::totalPredConcOverhead();
  2705   _mmu_tracker->update_conc_overhead(conc_overhead);
  2706 #if 0
  2707   gclog_or_tty->print(" CO %1.4lf TARGET %1.4lf",
  2708              conc_overhead, _mmu_tracker->max_gc_time());
  2709 #endif
  2713 uint G1CollectorPolicy::max_regions(int purpose) {
  2714   switch (purpose) {
  2715     case GCAllocForSurvived:
  2716       return G1MaxSurvivorRegions;
  2717     case GCAllocForTenured:
  2718       return UINT_MAX;
  2719     default:
  2720       return UINT_MAX;
  2721   };
  2724 void
  2725 G1CollectorPolicy_BestRegionsFirst::
  2726 set_single_region_collection_set(HeapRegion* hr) {
  2727   G1CollectorPolicy::set_single_region_collection_set(hr);
  2728   _collectionSetChooser->removeRegion(hr);
  2732 bool
  2733 G1CollectorPolicy_BestRegionsFirst::should_do_collection_pause(size_t
  2734                                                                word_size) {
  2735   assert(_g1->regions_accounted_for(), "Region leakage!");
  2736   // Initiate a pause when we reach the steady-state "used" target.
  2737   size_t used_hard = (_g1->capacity() / 100) * G1SteadyStateUsed;
  2738   size_t used_soft =
  2739    MAX2((_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta),
  2740         used_hard/2);
  2741   size_t used = _g1->used();
  2743   double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
  2745   size_t young_list_length = _g1->young_list_length();
  2746   bool reached_target_length = young_list_length >= _young_list_target_length;
  2748   if (in_young_gc_mode()) {
  2749     if (reached_target_length) {
  2750       assert( young_list_length > 0 && _g1->young_list_length() > 0,
  2751               "invariant" );
  2752       _target_pause_time_ms = max_pause_time_ms;
  2753       return true;
  2755   } else {
  2756     guarantee( false, "should not reach here" );
  2759   return false;
  2762 #ifndef PRODUCT
  2763 class HRSortIndexIsOKClosure: public HeapRegionClosure {
  2764   CollectionSetChooser* _chooser;
  2765 public:
  2766   HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
  2767     _chooser(chooser) {}
  2769   bool doHeapRegion(HeapRegion* r) {
  2770     if (!r->continuesHumongous()) {
  2771       assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
  2773     return false;
  2775 };
  2777 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
  2778   HRSortIndexIsOKClosure cl(_collectionSetChooser);
  2779   _g1->heap_region_iterate(&cl);
  2780   return true;
  2782 #endif
  2784 void
  2785 G1CollectorPolicy_BestRegionsFirst::
  2786 record_collection_pause_start(double start_time_sec, size_t start_used) {
  2787   G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
  2790 class NextNonCSElemFinder: public HeapRegionClosure {
  2791   HeapRegion* _res;
  2792 public:
  2793   NextNonCSElemFinder(): _res(NULL) {}
  2794   bool doHeapRegion(HeapRegion* r) {
  2795     if (!r->in_collection_set()) {
  2796       _res = r;
  2797       return true;
  2798     } else {
  2799       return false;
  2802   HeapRegion* res() { return _res; }
  2803 };
  2805 class KnownGarbageClosure: public HeapRegionClosure {
  2806   CollectionSetChooser* _hrSorted;
  2808 public:
  2809   KnownGarbageClosure(CollectionSetChooser* hrSorted) :
  2810     _hrSorted(hrSorted)
  2811   {}
  2813   bool doHeapRegion(HeapRegion* r) {
  2814     // We only include humongous regions in collection
  2815     // sets when concurrent mark shows that their contained object is
  2816     // unreachable.
  2818     // Do we have any marking information for this region?
  2819     if (r->is_marked()) {
  2820       // We don't include humongous regions in collection
  2821       // sets because we collect them immediately at the end of a marking
  2822       // cycle.  We also don't include young regions because we *must*
  2823       // include them in the next collection pause.
  2824       if (!r->isHumongous() && !r->is_young()) {
  2825         _hrSorted->addMarkedHeapRegion(r);
  2828     return false;
  2830 };
  2832 class ParKnownGarbageHRClosure: public HeapRegionClosure {
  2833   CollectionSetChooser* _hrSorted;
  2834   jint _marked_regions_added;
  2835   jint _chunk_size;
  2836   jint _cur_chunk_idx;
  2837   jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
  2838   int _worker;
  2839   int _invokes;
  2841   void get_new_chunk() {
  2842     _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
  2843     _cur_chunk_end = _cur_chunk_idx + _chunk_size;
  2845   void add_region(HeapRegion* r) {
  2846     if (_cur_chunk_idx == _cur_chunk_end) {
  2847       get_new_chunk();
  2849     assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
  2850     _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
  2851     _marked_regions_added++;
  2852     _cur_chunk_idx++;
  2855 public:
  2856   ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
  2857                            jint chunk_size,
  2858                            int worker) :
  2859     _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
  2860     _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
  2861     _invokes(0)
  2862   {}
  2864   bool doHeapRegion(HeapRegion* r) {
  2865     // We only include humongous regions in collection
  2866     // sets when concurrent mark shows that their contained object is
  2867     // unreachable.
  2868     _invokes++;
  2870     // Do we have any marking information for this region?
  2871     if (r->is_marked()) {
  2872       // We don't include humongous regions in collection
  2873       // sets because we collect them immediately at the end of a marking
  2874       // cycle.
  2875       // We also do not include young regions in collection sets
  2876       if (!r->isHumongous() && !r->is_young()) {
  2877         add_region(r);
  2880     return false;
  2882   jint marked_regions_added() { return _marked_regions_added; }
  2883   int invokes() { return _invokes; }
  2884 };
  2886 class ParKnownGarbageTask: public AbstractGangTask {
  2887   CollectionSetChooser* _hrSorted;
  2888   jint _chunk_size;
  2889   G1CollectedHeap* _g1;
  2890 public:
  2891   ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
  2892     AbstractGangTask("ParKnownGarbageTask"),
  2893     _hrSorted(hrSorted), _chunk_size(chunk_size),
  2894     _g1(G1CollectedHeap::heap())
  2895   {}
  2897   void work(int i) {
  2898     ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
  2899     // Back to zero for the claim value.
  2900     _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
  2901                                          HeapRegion::InitialClaimValue);
  2902     jint regions_added = parKnownGarbageCl.marked_regions_added();
  2903     _hrSorted->incNumMarkedHeapRegions(regions_added);
  2904     if (G1PrintParCleanupStats) {
  2905       gclog_or_tty->print("     Thread %d called %d times, added %d regions to list.\n",
  2906                  i, parKnownGarbageCl.invokes(), regions_added);
  2909 };
  2911 void
  2912 G1CollectorPolicy_BestRegionsFirst::
  2913 record_concurrent_mark_cleanup_end(size_t freed_bytes,
  2914                                    size_t max_live_bytes) {
  2915   double start;
  2916   if (G1PrintParCleanupStats) start = os::elapsedTime();
  2917   record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
  2919   _collectionSetChooser->clearMarkedHeapRegions();
  2920   double clear_marked_end;
  2921   if (G1PrintParCleanupStats) {
  2922     clear_marked_end = os::elapsedTime();
  2923     gclog_or_tty->print_cr("  clear marked regions + work1: %8.3f ms.",
  2924                   (clear_marked_end - start)*1000.0);
  2926   if (ParallelGCThreads > 0) {
  2927     const size_t OverpartitionFactor = 4;
  2928     const size_t MinChunkSize = 8;
  2929     const size_t ChunkSize =
  2930       MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
  2931            MinChunkSize);
  2932     _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
  2933                                                              ChunkSize);
  2934     ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
  2935                                             (int) ChunkSize);
  2936     _g1->workers()->run_task(&parKnownGarbageTask);
  2938     assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
  2939            "sanity check");
  2940   } else {
  2941     KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
  2942     _g1->heap_region_iterate(&knownGarbagecl);
  2944   double known_garbage_end;
  2945   if (G1PrintParCleanupStats) {
  2946     known_garbage_end = os::elapsedTime();
  2947     gclog_or_tty->print_cr("  compute known garbage: %8.3f ms.",
  2948                   (known_garbage_end - clear_marked_end)*1000.0);
  2950   _collectionSetChooser->sortMarkedHeapRegions();
  2951   double sort_end;
  2952   if (G1PrintParCleanupStats) {
  2953     sort_end = os::elapsedTime();
  2954     gclog_or_tty->print_cr("  sorting: %8.3f ms.",
  2955                   (sort_end - known_garbage_end)*1000.0);
  2958   record_concurrent_mark_cleanup_end_work2();
  2959   double work2_end;
  2960   if (G1PrintParCleanupStats) {
  2961     work2_end = os::elapsedTime();
  2962     gclog_or_tty->print_cr("  work2: %8.3f ms.",
  2963                   (work2_end - sort_end)*1000.0);
  2967 // Add the heap region to the collection set and return the conservative
  2968 // estimate of the number of live bytes.
  2969 void G1CollectorPolicy::
  2970 add_to_collection_set(HeapRegion* hr) {
  2971   if (G1TraceRegions) {
  2972     gclog_or_tty->print_cr("added region to cset %d:["PTR_FORMAT", "PTR_FORMAT"], "
  2973                   "top "PTR_FORMAT", young %s",
  2974                   hr->hrs_index(), hr->bottom(), hr->end(),
  2975                   hr->top(), (hr->is_young()) ? "YES" : "NO");
  2978   if (_g1->mark_in_progress())
  2979     _g1->concurrent_mark()->registerCSetRegion(hr);
  2981   assert(!hr->in_collection_set(),
  2982               "should not already be in the CSet");
  2983   hr->set_in_collection_set(true);
  2984   hr->set_next_in_collection_set(_collection_set);
  2985   _collection_set = hr;
  2986   _collection_set_size++;
  2987   _collection_set_bytes_used_before += hr->used();
  2988   _g1->register_region_with_in_cset_fast_test(hr);
  2991 void
  2992 G1CollectorPolicy_BestRegionsFirst::
  2993 choose_collection_set(HeapRegion* pop_region) {
  2994   double non_young_start_time_sec;
  2995   start_recording_regions();
  2997   if (pop_region != NULL) {
  2998     _target_pause_time_ms = (double) G1MaxPauseTimeMS;
  2999   } else {
  3000     guarantee(_target_pause_time_ms > -1.0,
  3001               "_target_pause_time_ms should have been set!");
  3004   // pop region is either null (and so is CS), or else it *is* the CS.
  3005   assert(_collection_set == pop_region, "Precondition");
  3007   double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
  3008   double predicted_pause_time_ms = base_time_ms;
  3010   double target_time_ms = _target_pause_time_ms;
  3011   double time_remaining_ms = target_time_ms - base_time_ms;
  3013   // the 10% and 50% values are arbitrary...
  3014   if (time_remaining_ms < 0.10*target_time_ms) {
  3015     time_remaining_ms = 0.50 * target_time_ms;
  3016     _within_target = false;
  3017   } else {
  3018     _within_target = true;
  3021   // We figure out the number of bytes available for future to-space.
  3022   // For new regions without marking information, we must assume the
  3023   // worst-case of complete survival.  If we have marking information for a
  3024   // region, we can bound the amount of live data.  We can add a number of
  3025   // such regions, as long as the sum of the live data bounds does not
  3026   // exceed the available evacuation space.
  3027   size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes;
  3029   size_t expansion_bytes =
  3030     _g1->expansion_regions() * HeapRegion::GrainBytes;
  3032   if (pop_region == NULL) {
  3033     _collection_set_bytes_used_before = 0;
  3034     _collection_set_size = 0;
  3037   // Adjust for expansion and slop.
  3038   max_live_bytes = max_live_bytes + expansion_bytes;
  3040   assert(pop_region != NULL || _g1->regions_accounted_for(), "Region leakage!");
  3042   HeapRegion* hr;
  3043   if (in_young_gc_mode()) {
  3044     double young_start_time_sec = os::elapsedTime();
  3046     if (G1PolicyVerbose > 0) {
  3047       gclog_or_tty->print_cr("Adding %d young regions to the CSet",
  3048                     _g1->young_list_length());
  3050     _young_cset_length  = 0;
  3051     _last_young_gc_full = full_young_gcs() ? true : false;
  3052     if (_last_young_gc_full)
  3053       ++_full_young_pause_num;
  3054     else
  3055       ++_partial_young_pause_num;
  3056     hr = _g1->pop_region_from_young_list();
  3057     while (hr != NULL) {
  3059       assert( hr->young_index_in_cset() == -1, "invariant" );
  3060       assert( hr->age_in_surv_rate_group() != -1, "invariant" );
  3061       hr->set_young_index_in_cset((int) _young_cset_length);
  3063       ++_young_cset_length;
  3064       double predicted_time_ms = predict_region_elapsed_time_ms(hr, true);
  3065       time_remaining_ms -= predicted_time_ms;
  3066       predicted_pause_time_ms += predicted_time_ms;
  3067       if (hr == pop_region) {
  3068         // The popular region was young.  Skip over it.
  3069         assert(hr->in_collection_set(), "It's the pop region.");
  3070       } else {
  3071         assert(!hr->in_collection_set(), "It's not the pop region.");
  3072         add_to_collection_set(hr);
  3073         record_cset_region(hr, true);
  3075       max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
  3076       if (G1PolicyVerbose > 0) {
  3077         gclog_or_tty->print_cr("  Added [" PTR_FORMAT ", " PTR_FORMAT") to CS.",
  3078                       hr->bottom(), hr->end());
  3079         gclog_or_tty->print_cr("    (" SIZE_FORMAT " KB left in heap.)",
  3080                       max_live_bytes/K);
  3082       hr = _g1->pop_region_from_young_list();
  3085     record_scan_only_regions(_g1->young_list_scan_only_length());
  3087     double young_end_time_sec = os::elapsedTime();
  3088     _recorded_young_cset_choice_time_ms =
  3089       (young_end_time_sec - young_start_time_sec) * 1000.0;
  3091     non_young_start_time_sec = os::elapsedTime();
  3093     if (_young_cset_length > 0 && _last_young_gc_full) {
  3094       // don't bother adding more regions...
  3095       goto choose_collection_set_end;
  3097   } else if (pop_region != NULL) {
  3098     // We're not in young mode, and we chose a popular region; don't choose
  3099     // any more.
  3100     return;
  3103   if (!in_young_gc_mode() || !full_young_gcs()) {
  3104     bool should_continue = true;
  3105     NumberSeq seq;
  3106     double avg_prediction = 100000000000000000.0; // something very large
  3107     do {
  3108       hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
  3109                                                       avg_prediction);
  3110       if (hr != NULL && !hr->popular()) {
  3111         double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
  3112         time_remaining_ms -= predicted_time_ms;
  3113         predicted_pause_time_ms += predicted_time_ms;
  3114         add_to_collection_set(hr);
  3115         record_cset_region(hr, false);
  3116         max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
  3117         if (G1PolicyVerbose > 0) {
  3118           gclog_or_tty->print_cr("    (" SIZE_FORMAT " KB left in heap.)",
  3119                         max_live_bytes/K);
  3121         seq.add(predicted_time_ms);
  3122         avg_prediction = seq.avg() + seq.sd();
  3124       should_continue =
  3125         ( hr != NULL) &&
  3126         ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0
  3127           : _collection_set_size < _young_list_fixed_length );
  3128     } while (should_continue);
  3130     if (!adaptive_young_list_length() &&
  3131         _collection_set_size < _young_list_fixed_length)
  3132       _should_revert_to_full_young_gcs  = true;
  3135 choose_collection_set_end:
  3136   count_CS_bytes_used();
  3138   end_recording_regions();
  3140   double non_young_end_time_sec = os::elapsedTime();
  3141   _recorded_non_young_cset_choice_time_ms =
  3142     (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
  3145 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
  3146   G1CollectorPolicy::record_full_collection_end();
  3147   _collectionSetChooser->updateAfterFullCollection();
  3150 void G1CollectorPolicy_BestRegionsFirst::
  3151 expand_if_possible(size_t numRegions) {
  3152   size_t expansion_bytes = numRegions * HeapRegion::GrainBytes;
  3153   _g1->expand(expansion_bytes);
  3156 void G1CollectorPolicy_BestRegionsFirst::
  3157 record_collection_pause_end(bool popular, bool abandoned) {
  3158   G1CollectorPolicy::record_collection_pause_end(popular, abandoned);
  3159   assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
  3162 // Local Variables: ***
  3163 // c-indentation-style: gnu ***
  3164 // End: ***

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