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

Thu, 19 Nov 2009 10:19:19 -0800

author
ysr
date
Thu, 19 Nov 2009 10:19:19 -0800
changeset 1522
23b9a8d315fc
parent 1521
89f1b9ae8991
child 1523
3fc996d4edd2
permissions
-rw-r--r--

6902701: G1: protect debugging code related to 6898948 with a debug flag
Summary: Protected stats dump with a new develop flag; other than for the dump, reconciled product and non-product behaviour in face of the error.
Reviewed-by: tonyp

     1 /*
     2  * Copyright 2001-2009 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   _summary(new Summary()),
    95   _abandoned_summary(new AbandonedSummary()),
    97 #ifndef PRODUCT
    98   _cur_clear_ct_time_ms(0.0),
    99   _min_clear_cc_time_ms(-1.0),
   100   _max_clear_cc_time_ms(-1.0),
   101   _cur_clear_cc_time_ms(0.0),
   102   _cum_clear_cc_time_ms(0.0),
   103   _num_cc_clears(0L),
   104 #endif
   106   _region_num_young(0),
   107   _region_num_tenured(0),
   108   _prev_region_num_young(0),
   109   _prev_region_num_tenured(0),
   111   _aux_num(10),
   112   _all_aux_times_ms(new NumberSeq[_aux_num]),
   113   _cur_aux_start_times_ms(new double[_aux_num]),
   114   _cur_aux_times_ms(new double[_aux_num]),
   115   _cur_aux_times_set(new bool[_aux_num]),
   117   _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   118   _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   119   _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
   121   // <NEW PREDICTION>
   123   _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   124   _prev_collection_pause_end_ms(0.0),
   125   _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
   126   _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
   127   _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   128   _cost_per_scan_only_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   129   _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
   130   _partially_young_cards_per_entry_ratio_seq(
   131                                          new TruncatedSeq(TruncatedSeqLength)),
   132   _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   133   _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   134   _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   135   _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
   136   _cost_per_scan_only_region_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
   137   _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   138   _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
   139   _non_young_other_cost_per_region_ms_seq(
   140                                          new TruncatedSeq(TruncatedSeqLength)),
   142   _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
   143   _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
   144   _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
   146   _pause_time_target_ms((double) MaxGCPauseMillis),
   148   // </NEW PREDICTION>
   150   _in_young_gc_mode(false),
   151   _full_young_gcs(true),
   152   _full_young_pause_num(0),
   153   _partial_young_pause_num(0),
   155   _during_marking(false),
   156   _in_marking_window(false),
   157   _in_marking_window_im(false),
   159   _known_garbage_ratio(0.0),
   160   _known_garbage_bytes(0),
   162   _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
   163   _target_pause_time_ms(-1.0),
   165    _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
   167   _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
   168   _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
   170   _recent_avg_pause_time_ratio(0.0),
   171   _num_markings(0),
   172   _n_marks(0),
   173   _n_pauses_at_mark_end(0),
   175   _all_full_gc_times_ms(new NumberSeq()),
   177   // G1PausesBtwnConcMark defaults to -1
   178   // so the hack is to do the cast  QQQ FIXME
   179   _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
   180   _n_marks_since_last_pause(0),
   181   _conc_mark_initiated(false),
   182   _should_initiate_conc_mark(false),
   183   _should_revert_to_full_young_gcs(false),
   184   _last_full_young_gc(false),
   186   _prev_collection_pause_used_at_end_bytes(0),
   188   _collection_set(NULL),
   189 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
   190 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
   191 #endif // _MSC_VER
   193   _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
   194                                                  G1YoungSurvRateNumRegionsSummary)),
   195   _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
   196                                               G1YoungSurvRateNumRegionsSummary)),
   197   // add here any more surv rate groups
   198   _recorded_survivor_regions(0),
   199   _recorded_survivor_head(NULL),
   200   _recorded_survivor_tail(NULL),
   201   _survivors_age_table(true)
   203 {
   204   // Set up the region size and associated fields. Given that the
   205   // policy is created before the heap, we have to set this up here,
   206   // so it's done as soon as possible.
   207   HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
   209   _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
   210   _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
   212   _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
   213   _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
   214   _par_last_scan_only_times_ms = new double[_parallel_gc_threads];
   215   _par_last_scan_only_regions_scanned = new double[_parallel_gc_threads];
   217   _par_last_update_rs_start_times_ms = new double[_parallel_gc_threads];
   218   _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
   219   _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
   221   _par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads];
   222   _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
   223   _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads];
   225   _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
   227   _par_last_termination_times_ms = new double[_parallel_gc_threads];
   229   // start conservatively
   230   _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
   232   // <NEW PREDICTION>
   234   int index;
   235   if (ParallelGCThreads == 0)
   236     index = 0;
   237   else if (ParallelGCThreads > 8)
   238     index = 7;
   239   else
   240     index = ParallelGCThreads - 1;
   242   _pending_card_diff_seq->add(0.0);
   243   _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
   244   _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
   245   _cost_per_scan_only_region_ms_seq->add(
   246                                  cost_per_scan_only_region_ms_defaults[index]);
   247   _fully_young_cards_per_entry_ratio_seq->add(
   248                             fully_young_cards_per_entry_ratio_defaults[index]);
   249   _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
   250   _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
   251   _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
   252   _young_other_cost_per_region_ms_seq->add(
   253                                young_other_cost_per_region_ms_defaults[index]);
   254   _non_young_other_cost_per_region_ms_seq->add(
   255                            non_young_other_cost_per_region_ms_defaults[index]);
   257   // </NEW PREDICTION>
   259   double time_slice  = (double) GCPauseIntervalMillis / 1000.0;
   260   double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
   261   guarantee(max_gc_time < time_slice,
   262             "Max GC time should not be greater than the time slice");
   263   _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
   264   _sigma = (double) G1ConfidencePercent / 100.0;
   266   // start conservatively (around 50ms is about right)
   267   _concurrent_mark_init_times_ms->add(0.05);
   268   _concurrent_mark_remark_times_ms->add(0.05);
   269   _concurrent_mark_cleanup_times_ms->add(0.20);
   270   _tenuring_threshold = MaxTenuringThreshold;
   272   if (G1UseSurvivorSpaces) {
   273     // if G1FixedSurvivorSpaceSize is 0 which means the size is not
   274     // fixed, then _max_survivor_regions will be calculated at
   275     // calculate_young_list_target_config during initialization
   276     _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
   277   } else {
   278     _max_survivor_regions = 0;
   279   }
   281   initialize_all();
   282 }
   284 // Increment "i", mod "len"
   285 static void inc_mod(int& i, int len) {
   286   i++; if (i == len) i = 0;
   287 }
   289 void G1CollectorPolicy::initialize_flags() {
   290   set_min_alignment(HeapRegion::GrainBytes);
   291   set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
   292   if (SurvivorRatio < 1) {
   293     vm_exit_during_initialization("Invalid survivor ratio specified");
   294   }
   295   CollectorPolicy::initialize_flags();
   296 }
   298 void G1CollectorPolicy::init() {
   299   // Set aside an initial future to_space.
   300   _g1 = G1CollectedHeap::heap();
   301   size_t regions = Universe::heap()->capacity() / HeapRegion::GrainBytes;
   303   assert(Heap_lock->owned_by_self(), "Locking discipline.");
   305   if (G1SteadyStateUsed < 50) {
   306     vm_exit_during_initialization("G1SteadyStateUsed must be at least 50%.");
   307   }
   309   initialize_gc_policy_counters();
   311   if (G1Gen) {
   312     _in_young_gc_mode = true;
   314     if (G1YoungGenSize == 0) {
   315       set_adaptive_young_list_length(true);
   316       _young_list_fixed_length = 0;
   317     } else {
   318       set_adaptive_young_list_length(false);
   319       _young_list_fixed_length = (G1YoungGenSize / HeapRegion::GrainBytes);
   320     }
   321      _free_regions_at_end_of_collection = _g1->free_regions();
   322      _scan_only_regions_at_end_of_collection = 0;
   323      calculate_young_list_min_length();
   324      guarantee( _young_list_min_length == 0, "invariant, not enough info" );
   325      calculate_young_list_target_config();
   326    } else {
   327      _young_list_fixed_length = 0;
   328     _in_young_gc_mode = false;
   329   }
   330 }
   332 // Create the jstat counters for the policy.
   333 void G1CollectorPolicy::initialize_gc_policy_counters()
   334 {
   335   _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen);
   336 }
   338 void G1CollectorPolicy::calculate_young_list_min_length() {
   339   _young_list_min_length = 0;
   341   if (!adaptive_young_list_length())
   342     return;
   344   if (_alloc_rate_ms_seq->num() > 3) {
   345     double now_sec = os::elapsedTime();
   346     double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
   347     double alloc_rate_ms = predict_alloc_rate_ms();
   348     int min_regions = (int) ceil(alloc_rate_ms * when_ms);
   349     int current_region_num = (int) _g1->young_list_length();
   350     _young_list_min_length = min_regions + current_region_num;
   351   }
   352 }
   354 void G1CollectorPolicy::calculate_young_list_target_config() {
   355   if (adaptive_young_list_length()) {
   356     size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
   357     calculate_young_list_target_config(rs_lengths);
   358   } else {
   359     if (full_young_gcs())
   360       _young_list_target_length = _young_list_fixed_length;
   361     else
   362       _young_list_target_length = _young_list_fixed_length / 2;
   363     _young_list_target_length = MAX2(_young_list_target_length, (size_t)1);
   364     size_t so_length = calculate_optimal_so_length(_young_list_target_length);
   365     guarantee( so_length < _young_list_target_length, "invariant" );
   366     _young_list_so_prefix_length = so_length;
   367   }
   368   calculate_survivors_policy();
   369 }
   371 // This method calculate the optimal scan-only set for a fixed young
   372 // gen size. I couldn't work out how to reuse the more elaborate one,
   373 // i.e. calculate_young_list_target_config(rs_length), as the loops are
   374 // fundamentally different (the other one finds a config for different
   375 // S-O lengths, whereas here we need to do the opposite).
   376 size_t G1CollectorPolicy::calculate_optimal_so_length(
   377                                                     size_t young_list_length) {
   378   if (!G1UseScanOnlyPrefix)
   379     return 0;
   381   if (_all_pause_times_ms->num() < 3) {
   382     // we won't use a scan-only set at the beginning to allow the rest
   383     // of the predictors to warm up
   384     return 0;
   385   }
   387   if (_cost_per_scan_only_region_ms_seq->num() < 3) {
   388     // then, we'll only set the S-O set to 1 for a little bit of time,
   389     // to get enough information on the scanning cost
   390     return 1;
   391   }
   393   size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
   394   size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
   395   size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
   396   size_t scanned_cards;
   397   if (full_young_gcs())
   398     scanned_cards = predict_young_card_num(adj_rs_lengths);
   399   else
   400     scanned_cards = predict_non_young_card_num(adj_rs_lengths);
   401   double base_time_ms = predict_base_elapsed_time_ms(pending_cards,
   402                                                      scanned_cards);
   404   size_t so_length = 0;
   405   double max_gc_eff = 0.0;
   406   for (size_t i = 0; i < young_list_length; ++i) {
   407     double gc_eff = 0.0;
   408     double pause_time_ms = 0.0;
   409     predict_gc_eff(young_list_length, i, base_time_ms,
   410                    &gc_eff, &pause_time_ms);
   411     if (gc_eff > max_gc_eff) {
   412       max_gc_eff = gc_eff;
   413       so_length = i;
   414     }
   415   }
   417   // set it to 95% of the optimal to make sure we sample the "area"
   418   // around the optimal length to get up-to-date survival rate data
   419   return so_length * 950 / 1000;
   420 }
   422 // This is a really cool piece of code! It finds the best
   423 // target configuration (young length / scan-only prefix length) so
   424 // that GC efficiency is maximized and that we also meet a pause
   425 // time. It's a triple nested loop. These loops are explained below
   426 // from the inside-out :-)
   427 //
   428 // (a) The innermost loop will try to find the optimal young length
   429 // for a fixed S-O length. It uses a binary search to speed up the
   430 // process. We assume that, for a fixed S-O length, as we add more
   431 // young regions to the CSet, the GC efficiency will only go up (I'll
   432 // skip the proof). So, using a binary search to optimize this process
   433 // makes perfect sense.
   434 //
   435 // (b) The middle loop will fix the S-O length before calling the
   436 // innermost one. It will vary it between two parameters, increasing
   437 // it by a given increment.
   438 //
   439 // (c) The outermost loop will call the middle loop three times.
   440 //   (1) The first time it will explore all possible S-O length values
   441 //   from 0 to as large as it can get, using a coarse increment (to
   442 //   quickly "home in" to where the optimal seems to be).
   443 //   (2) The second time it will explore the values around the optimal
   444 //   that was found by the first iteration using a fine increment.
   445 //   (3) Once the optimal config has been determined by the second
   446 //   iteration, we'll redo the calculation, but setting the S-O length
   447 //   to 95% of the optimal to make sure we sample the "area"
   448 //   around the optimal length to get up-to-date survival rate data
   449 //
   450 // Termination conditions for the iterations are several: the pause
   451 // time is over the limit, we do not have enough to-space, etc.
   453 void G1CollectorPolicy::calculate_young_list_target_config(size_t rs_lengths) {
   454   guarantee( adaptive_young_list_length(), "pre-condition" );
   456   double start_time_sec = os::elapsedTime();
   457   size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1MinReservePercent);
   458   min_reserve_perc = MIN2((size_t) 50, min_reserve_perc);
   459   size_t reserve_regions =
   460     (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0);
   462   if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
   463     // we are in fully-young mode and there are free regions in the heap
   465     double survivor_regions_evac_time =
   466         predict_survivor_regions_evac_time();
   468     size_t min_so_length = 0;
   469     size_t max_so_length = 0;
   471     if (G1UseScanOnlyPrefix) {
   472       if (_all_pause_times_ms->num() < 3) {
   473         // we won't use a scan-only set at the beginning to allow the rest
   474         // of the predictors to warm up
   475         min_so_length = 0;
   476         max_so_length = 0;
   477       } else if (_cost_per_scan_only_region_ms_seq->num() < 3) {
   478         // then, we'll only set the S-O set to 1 for a little bit of time,
   479         // to get enough information on the scanning cost
   480         min_so_length = 1;
   481         max_so_length = 1;
   482       } else if (_in_marking_window || _last_full_young_gc) {
   483         // no S-O prefix during a marking phase either, as at the end
   484         // of the marking phase we'll have to use a very small young
   485         // length target to fill up the rest of the CSet with
   486         // non-young regions and, if we have lots of scan-only regions
   487         // left-over, we will not be able to add any more non-young
   488         // regions.
   489         min_so_length = 0;
   490         max_so_length = 0;
   491       } else {
   492         // this is the common case; we'll never reach the maximum, we
   493         // one of the end conditions will fire well before that
   494         // (hopefully!)
   495         min_so_length = 0;
   496         max_so_length = _free_regions_at_end_of_collection - 1;
   497       }
   498     } else {
   499       // no S-O prefix, as the switch is not set, but we still need to
   500       // do one iteration to calculate the best young target that
   501       // meets the pause time; this way we reuse the same code instead
   502       // of replicating it
   503       min_so_length = 0;
   504       max_so_length = 0;
   505     }
   507     double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
   508     size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
   509     size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
   510     size_t scanned_cards;
   511     if (full_young_gcs())
   512       scanned_cards = predict_young_card_num(adj_rs_lengths);
   513     else
   514       scanned_cards = predict_non_young_card_num(adj_rs_lengths);
   515     // calculate this once, so that we don't have to recalculate it in
   516     // the innermost loop
   517     double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards)
   518                           + survivor_regions_evac_time;
   519     // the result
   520     size_t final_young_length = 0;
   521     size_t final_so_length = 0;
   522     double final_gc_eff = 0.0;
   523     // we'll also keep track of how many times we go into the inner loop
   524     // this is for profiling reasons
   525     size_t calculations = 0;
   527     // this determines which of the three iterations the outer loop is in
   528     typedef enum {
   529       pass_type_coarse,
   530       pass_type_fine,
   531       pass_type_final
   532     } pass_type_t;
   534     // range of the outer loop's iteration
   535     size_t from_so_length   = min_so_length;
   536     size_t to_so_length     = max_so_length;
   537     guarantee( from_so_length <= to_so_length, "invariant" );
   539     // this will keep the S-O length that's found by the second
   540     // iteration of the outer loop; we'll keep it just in case the third
   541     // iteration fails to find something
   542     size_t fine_so_length   = 0;
   544     // the increment step for the coarse (first) iteration
   545     size_t so_coarse_increments = 5;
   547     // the common case, we'll start with the coarse iteration
   548     pass_type_t pass = pass_type_coarse;
   549     size_t so_length_incr = so_coarse_increments;
   551     if (from_so_length == to_so_length) {
   552       // not point in doing the coarse iteration, we'll go directly into
   553       // the fine one (we essentially trying to find the optimal young
   554       // length for a fixed S-O length).
   555       so_length_incr = 1;
   556       pass = pass_type_final;
   557     } else if (to_so_length - from_so_length < 3 * so_coarse_increments) {
   558       // again, the range is too short so no point in foind the coarse
   559       // iteration either
   560       so_length_incr = 1;
   561       pass = pass_type_fine;
   562     }
   564     bool done = false;
   565     // this is the outermost loop
   566     while (!done) {
   567 #ifdef TRACE_CALC_YOUNG_CONFIG
   568       // leave this in for debugging, just in case
   569       gclog_or_tty->print_cr("searching between " SIZE_FORMAT " and " SIZE_FORMAT
   570                              ", incr " SIZE_FORMAT ", pass %s",
   571                              from_so_length, to_so_length, so_length_incr,
   572                              (pass == pass_type_coarse) ? "coarse" :
   573                              (pass == pass_type_fine) ? "fine" : "final");
   574 #endif // TRACE_CALC_YOUNG_CONFIG
   576       size_t so_length = from_so_length;
   577       size_t init_free_regions =
   578         MAX2((size_t)0,
   579              _free_regions_at_end_of_collection +
   580              _scan_only_regions_at_end_of_collection - reserve_regions);
   582       // this determines whether a configuration was found
   583       bool gc_eff_set = false;
   584       // this is the middle loop
   585       while (so_length <= to_so_length) {
   586         // base time, which excludes region-related time; again we
   587         // calculate it once to avoid recalculating it in the
   588         // innermost loop
   589         double base_time_with_so_ms =
   590                            base_time_ms + predict_scan_only_time_ms(so_length);
   591         // it's already over the pause target, go around
   592         if (base_time_with_so_ms > target_pause_time_ms)
   593           break;
   595         size_t starting_young_length = so_length+1;
   597         // we make sure that the short young length that makes sense
   598         // (one more than the S-O length) is feasible
   599         size_t min_young_length = starting_young_length;
   600         double min_gc_eff;
   601         bool min_ok;
   602         ++calculations;
   603         min_ok = predict_gc_eff(min_young_length, so_length,
   604                                 base_time_with_so_ms,
   605                                 init_free_regions, target_pause_time_ms,
   606                                 &min_gc_eff);
   608         if (min_ok) {
   609           // the shortest young length is indeed feasible; we'll know
   610           // set up the max young length and we'll do a binary search
   611           // between min_young_length and max_young_length
   612           size_t max_young_length = _free_regions_at_end_of_collection - 1;
   613           double max_gc_eff = 0.0;
   614           bool max_ok = false;
   616           // the innermost loop! (finally!)
   617           while (max_young_length > min_young_length) {
   618             // we'll make sure that min_young_length is always at a
   619             // feasible config
   620             guarantee( min_ok, "invariant" );
   622             ++calculations;
   623             max_ok = predict_gc_eff(max_young_length, so_length,
   624                                     base_time_with_so_ms,
   625                                     init_free_regions, target_pause_time_ms,
   626                                     &max_gc_eff);
   628             size_t diff = (max_young_length - min_young_length) / 2;
   629             if (max_ok) {
   630               min_young_length = max_young_length;
   631               min_gc_eff = max_gc_eff;
   632               min_ok = true;
   633             }
   634             max_young_length = min_young_length + diff;
   635           }
   637           // the innermost loop found a config
   638           guarantee( min_ok, "invariant" );
   639           if (min_gc_eff > final_gc_eff) {
   640             // it's the best config so far, so we'll keep it
   641             final_gc_eff = min_gc_eff;
   642             final_young_length = min_young_length;
   643             final_so_length = so_length;
   644             gc_eff_set = true;
   645           }
   646         }
   648         // incremental the fixed S-O length and go around
   649         so_length += so_length_incr;
   650       }
   652       // this is the end of the outermost loop and we need to decide
   653       // what to do during the next iteration
   654       if (pass == pass_type_coarse) {
   655         // we just did the coarse pass (first iteration)
   657         if (!gc_eff_set)
   658           // we didn't find a feasible config so we'll just bail out; of
   659           // course, it might be the case that we missed it; but I'd say
   660           // it's a bit unlikely
   661           done = true;
   662         else {
   663           // We did find a feasible config with optimal GC eff during
   664           // the first pass. So the second pass we'll only consider the
   665           // S-O lengths around that config with a fine increment.
   667           guarantee( so_length_incr == so_coarse_increments, "invariant" );
   668           guarantee( final_so_length >= min_so_length, "invariant" );
   670 #ifdef TRACE_CALC_YOUNG_CONFIG
   671           // leave this in for debugging, just in case
   672           gclog_or_tty->print_cr("  coarse pass: SO length " SIZE_FORMAT,
   673                                  final_so_length);
   674 #endif // TRACE_CALC_YOUNG_CONFIG
   676           from_so_length =
   677             (final_so_length - min_so_length > so_coarse_increments) ?
   678             final_so_length - so_coarse_increments + 1 : min_so_length;
   679           to_so_length =
   680             (max_so_length - final_so_length > so_coarse_increments) ?
   681             final_so_length + so_coarse_increments - 1 : max_so_length;
   683           pass = pass_type_fine;
   684           so_length_incr = 1;
   685         }
   686       } else if (pass == pass_type_fine) {
   687         // we just finished the second pass
   689         if (!gc_eff_set) {
   690           // we didn't find a feasible config (yes, it's possible;
   691           // notice that, sometimes, we go directly into the fine
   692           // iteration and skip the coarse one) so we bail out
   693           done = true;
   694         } else {
   695           // We did find a feasible config with optimal GC eff
   696           guarantee( so_length_incr == 1, "invariant" );
   698           if (final_so_length == 0) {
   699             // The config is of an empty S-O set, so we'll just bail out
   700             done = true;
   701           } else {
   702             // we'll go around once more, setting the S-O length to 95%
   703             // of the optimal
   704             size_t new_so_length = 950 * final_so_length / 1000;
   706 #ifdef TRACE_CALC_YOUNG_CONFIG
   707             // leave this in for debugging, just in case
   708             gclog_or_tty->print_cr("  fine pass: SO length " SIZE_FORMAT
   709                                    ", setting it to " SIZE_FORMAT,
   710                                     final_so_length, new_so_length);
   711 #endif // TRACE_CALC_YOUNG_CONFIG
   713             from_so_length = new_so_length;
   714             to_so_length = new_so_length;
   715             fine_so_length = final_so_length;
   717             pass = pass_type_final;
   718           }
   719         }
   720       } else if (pass == pass_type_final) {
   721         // we just finished the final (third) pass
   723         if (!gc_eff_set)
   724           // we didn't find a feasible config, so we'll just use the one
   725           // we found during the second pass, which we saved
   726           final_so_length = fine_so_length;
   728         // and we're done!
   729         done = true;
   730       } else {
   731         guarantee( false, "should never reach here" );
   732       }
   734       // we now go around the outermost loop
   735     }
   737     // we should have at least one region in the target young length
   738     _young_list_target_length =
   739         MAX2((size_t) 1, final_young_length + _recorded_survivor_regions);
   740     if (final_so_length >= final_young_length)
   741       // and we need to ensure that the S-O length is not greater than
   742       // the target young length (this is being a bit careful)
   743       final_so_length = 0;
   744     _young_list_so_prefix_length = final_so_length;
   745     guarantee( !_in_marking_window || !_last_full_young_gc ||
   746                _young_list_so_prefix_length == 0, "invariant" );
   748     // let's keep an eye of how long we spend on this calculation
   749     // right now, I assume that we'll print it when we need it; we
   750     // should really adde it to the breakdown of a pause
   751     double end_time_sec = os::elapsedTime();
   752     double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
   754 #ifdef TRACE_CALC_YOUNG_CONFIG
   755     // leave this in for debugging, just in case
   756     gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT
   757                            ", SO = " SIZE_FORMAT ", "
   758                            "elapsed %1.2lf ms, calcs: " SIZE_FORMAT " (%s%s) "
   759                            SIZE_FORMAT SIZE_FORMAT,
   760                            target_pause_time_ms,
   761                            _young_list_target_length - _young_list_so_prefix_length,
   762                            _young_list_so_prefix_length,
   763                            elapsed_time_ms,
   764                            calculations,
   765                            full_young_gcs() ? "full" : "partial",
   766                            should_initiate_conc_mark() ? " i-m" : "",
   767                            _in_marking_window,
   768                            _in_marking_window_im);
   769 #endif // TRACE_CALC_YOUNG_CONFIG
   771     if (_young_list_target_length < _young_list_min_length) {
   772       // bummer; this means that, if we do a pause when the optimal
   773       // config dictates, we'll violate the pause spacing target (the
   774       // min length was calculate based on the application's current
   775       // alloc rate);
   777       // so, we have to bite the bullet, and allocate the minimum
   778       // number. We'll violate our target, but we just can't meet it.
   780       size_t so_length = 0;
   781       // a note further up explains why we do not want an S-O length
   782       // during marking
   783       if (!_in_marking_window && !_last_full_young_gc)
   784         // but we can still try to see whether we can find an optimal
   785         // S-O length
   786         so_length = calculate_optimal_so_length(_young_list_min_length);
   788 #ifdef TRACE_CALC_YOUNG_CONFIG
   789       // leave this in for debugging, just in case
   790       gclog_or_tty->print_cr("adjusted target length from "
   791                              SIZE_FORMAT " to " SIZE_FORMAT
   792                              ", SO " SIZE_FORMAT,
   793                              _young_list_target_length, _young_list_min_length,
   794                              so_length);
   795 #endif // TRACE_CALC_YOUNG_CONFIG
   797       _young_list_target_length =
   798         MAX2(_young_list_min_length, (size_t)1);
   799       _young_list_so_prefix_length = so_length;
   800     }
   801   } else {
   802     // we are in a partially-young mode or we've run out of regions (due
   803     // to evacuation failure)
   805 #ifdef TRACE_CALC_YOUNG_CONFIG
   806     // leave this in for debugging, just in case
   807     gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
   808                            ", SO " SIZE_FORMAT,
   809                            _young_list_min_length, 0);
   810 #endif // TRACE_CALC_YOUNG_CONFIG
   812     // we'll do the pause as soon as possible and with no S-O prefix
   813     // (see above for the reasons behind the latter)
   814     _young_list_target_length =
   815       MAX2(_young_list_min_length, (size_t) 1);
   816     _young_list_so_prefix_length = 0;
   817   }
   819   _rs_lengths_prediction = rs_lengths;
   820 }
   822 // This is used by: calculate_optimal_so_length(length). It returns
   823 // the GC eff and predicted pause time for a particular config
   824 void
   825 G1CollectorPolicy::predict_gc_eff(size_t young_length,
   826                                   size_t so_length,
   827                                   double base_time_ms,
   828                                   double* ret_gc_eff,
   829                                   double* ret_pause_time_ms) {
   830   double so_time_ms = predict_scan_only_time_ms(so_length);
   831   double accum_surv_rate_adj = 0.0;
   832   if (so_length > 0)
   833     accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
   834   double accum_surv_rate =
   835     accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
   836   size_t bytes_to_copy =
   837     (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
   838   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
   839   double young_other_time_ms =
   840                        predict_young_other_time_ms(young_length - so_length);
   841   double pause_time_ms =
   842                 base_time_ms + so_time_ms + copy_time_ms + young_other_time_ms;
   843   size_t reclaimed_bytes =
   844     (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
   845   double gc_eff = (double) reclaimed_bytes / pause_time_ms;
   847   *ret_gc_eff = gc_eff;
   848   *ret_pause_time_ms = pause_time_ms;
   849 }
   851 // This is used by: calculate_young_list_target_config(rs_length). It
   852 // returns the GC eff of a particular config. It returns false if that
   853 // config violates any of the end conditions of the search in the
   854 // calling method, or true upon success. The end conditions were put
   855 // here since it's called twice and it was best not to replicate them
   856 // in the caller. Also, passing the parameteres avoids having to
   857 // recalculate them in the innermost loop.
   858 bool
   859 G1CollectorPolicy::predict_gc_eff(size_t young_length,
   860                                   size_t so_length,
   861                                   double base_time_with_so_ms,
   862                                   size_t init_free_regions,
   863                                   double target_pause_time_ms,
   864                                   double* ret_gc_eff) {
   865   *ret_gc_eff = 0.0;
   867   if (young_length >= init_free_regions)
   868     // end condition 1: not enough space for the young regions
   869     return false;
   871   double accum_surv_rate_adj = 0.0;
   872   if (so_length > 0)
   873     accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
   874   double accum_surv_rate =
   875     accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
   876   size_t bytes_to_copy =
   877     (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
   878   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
   879   double young_other_time_ms =
   880                        predict_young_other_time_ms(young_length - so_length);
   881   double pause_time_ms =
   882                    base_time_with_so_ms + copy_time_ms + young_other_time_ms;
   884   if (pause_time_ms > target_pause_time_ms)
   885     // end condition 2: over the target pause time
   886     return false;
   888   size_t reclaimed_bytes =
   889     (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
   890   size_t free_bytes =
   891                  (init_free_regions - young_length) * HeapRegion::GrainBytes;
   893   if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes)
   894     // end condition 3: out of to-space (conservatively)
   895     return false;
   897   // success!
   898   double gc_eff = (double) reclaimed_bytes / pause_time_ms;
   899   *ret_gc_eff = gc_eff;
   901   return true;
   902 }
   904 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
   905   double survivor_regions_evac_time = 0.0;
   906   for (HeapRegion * r = _recorded_survivor_head;
   907        r != NULL && r != _recorded_survivor_tail->get_next_young_region();
   908        r = r->get_next_young_region()) {
   909     survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
   910   }
   911   return survivor_regions_evac_time;
   912 }
   914 void G1CollectorPolicy::check_prediction_validity() {
   915   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
   917   size_t rs_lengths = _g1->young_list_sampled_rs_lengths();
   918   if (rs_lengths > _rs_lengths_prediction) {
   919     // add 10% to avoid having to recalculate often
   920     size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
   921     calculate_young_list_target_config(rs_lengths_prediction);
   922   }
   923 }
   925 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
   926                                                bool is_tlab,
   927                                                bool* gc_overhead_limit_was_exceeded) {
   928   guarantee(false, "Not using this policy feature yet.");
   929   return NULL;
   930 }
   932 // This method controls how a collector handles one or more
   933 // of its generations being fully allocated.
   934 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
   935                                                        bool is_tlab) {
   936   guarantee(false, "Not using this policy feature yet.");
   937   return NULL;
   938 }
   941 #ifndef PRODUCT
   942 bool G1CollectorPolicy::verify_young_ages() {
   943   HeapRegion* head = _g1->young_list_first_region();
   944   return
   945     verify_young_ages(head, _short_lived_surv_rate_group);
   946   // also call verify_young_ages on any additional surv rate groups
   947 }
   949 bool
   950 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
   951                                      SurvRateGroup *surv_rate_group) {
   952   guarantee( surv_rate_group != NULL, "pre-condition" );
   954   const char* name = surv_rate_group->name();
   955   bool ret = true;
   956   int prev_age = -1;
   958   for (HeapRegion* curr = head;
   959        curr != NULL;
   960        curr = curr->get_next_young_region()) {
   961     SurvRateGroup* group = curr->surv_rate_group();
   962     if (group == NULL && !curr->is_survivor()) {
   963       gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
   964       ret = false;
   965     }
   967     if (surv_rate_group == group) {
   968       int age = curr->age_in_surv_rate_group();
   970       if (age < 0) {
   971         gclog_or_tty->print_cr("## %s: encountered negative age", name);
   972         ret = false;
   973       }
   975       if (age <= prev_age) {
   976         gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
   977                                "(%d, %d)", name, age, prev_age);
   978         ret = false;
   979       }
   980       prev_age = age;
   981     }
   982   }
   984   return ret;
   985 }
   986 #endif // PRODUCT
   988 void G1CollectorPolicy::record_full_collection_start() {
   989   _cur_collection_start_sec = os::elapsedTime();
   990   // Release the future to-space so that it is available for compaction into.
   991   _g1->set_full_collection();
   992 }
   994 void G1CollectorPolicy::record_full_collection_end() {
   995   // Consider this like a collection pause for the purposes of allocation
   996   // since last pause.
   997   double end_sec = os::elapsedTime();
   998   double full_gc_time_sec = end_sec - _cur_collection_start_sec;
   999   double full_gc_time_ms = full_gc_time_sec * 1000.0;
  1001   _all_full_gc_times_ms->add(full_gc_time_ms);
  1003   update_recent_gc_times(end_sec, full_gc_time_ms);
  1005   _g1->clear_full_collection();
  1007   // "Nuke" the heuristics that control the fully/partially young GC
  1008   // transitions and make sure we start with fully young GCs after the
  1009   // Full GC.
  1010   set_full_young_gcs(true);
  1011   _last_full_young_gc = false;
  1012   _should_revert_to_full_young_gcs = false;
  1013   _should_initiate_conc_mark = false;
  1014   _known_garbage_bytes = 0;
  1015   _known_garbage_ratio = 0.0;
  1016   _in_marking_window = false;
  1017   _in_marking_window_im = false;
  1019   _short_lived_surv_rate_group->record_scan_only_prefix(0);
  1020   _short_lived_surv_rate_group->start_adding_regions();
  1021   // also call this on any additional surv rate groups
  1023   record_survivor_regions(0, NULL, NULL);
  1025   _prev_region_num_young   = _region_num_young;
  1026   _prev_region_num_tenured = _region_num_tenured;
  1028   _free_regions_at_end_of_collection = _g1->free_regions();
  1029   _scan_only_regions_at_end_of_collection = 0;
  1030   // Reset survivors SurvRateGroup.
  1031   _survivor_surv_rate_group->reset();
  1032   calculate_young_list_min_length();
  1033   calculate_young_list_target_config();
  1036 void G1CollectorPolicy::record_before_bytes(size_t bytes) {
  1037   _bytes_in_to_space_before_gc += bytes;
  1040 void G1CollectorPolicy::record_after_bytes(size_t bytes) {
  1041   _bytes_in_to_space_after_gc += bytes;
  1044 void G1CollectorPolicy::record_stop_world_start() {
  1045   _stop_world_start = os::elapsedTime();
  1048 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
  1049                                                       size_t start_used) {
  1050   if (PrintGCDetails) {
  1051     gclog_or_tty->stamp(PrintGCTimeStamps);
  1052     gclog_or_tty->print("[GC pause");
  1053     if (in_young_gc_mode())
  1054       gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
  1057   assert(_g1->used_regions() == _g1->recalculate_used_regions(),
  1058          "sanity");
  1059   assert(_g1->used() == _g1->recalculate_used(), "sanity");
  1061   double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
  1062   _all_stop_world_times_ms->add(s_w_t_ms);
  1063   _stop_world_start = 0.0;
  1065   _cur_collection_start_sec = start_time_sec;
  1066   _cur_collection_pause_used_at_start_bytes = start_used;
  1067   _cur_collection_pause_used_regions_at_start = _g1->used_regions();
  1068   _pending_cards = _g1->pending_card_num();
  1069   _max_pending_cards = _g1->max_pending_card_num();
  1071   _bytes_in_to_space_before_gc = 0;
  1072   _bytes_in_to_space_after_gc = 0;
  1073   _bytes_in_collection_set_before_gc = 0;
  1075 #ifdef DEBUG
  1076   // initialise these to something well known so that we can spot
  1077   // if they are not set properly
  1079   for (int i = 0; i < _parallel_gc_threads; ++i) {
  1080     _par_last_ext_root_scan_times_ms[i] = -666.0;
  1081     _par_last_mark_stack_scan_times_ms[i] = -666.0;
  1082     _par_last_scan_only_times_ms[i] = -666.0;
  1083     _par_last_scan_only_regions_scanned[i] = -666.0;
  1084     _par_last_update_rs_start_times_ms[i] = -666.0;
  1085     _par_last_update_rs_times_ms[i] = -666.0;
  1086     _par_last_update_rs_processed_buffers[i] = -666.0;
  1087     _par_last_scan_rs_start_times_ms[i] = -666.0;
  1088     _par_last_scan_rs_times_ms[i] = -666.0;
  1089     _par_last_scan_new_refs_times_ms[i] = -666.0;
  1090     _par_last_obj_copy_times_ms[i] = -666.0;
  1091     _par_last_termination_times_ms[i] = -666.0;
  1093 #endif
  1095   for (int i = 0; i < _aux_num; ++i) {
  1096     _cur_aux_times_ms[i] = 0.0;
  1097     _cur_aux_times_set[i] = false;
  1100   _satb_drain_time_set = false;
  1101   _last_satb_drain_processed_buffers = -1;
  1103   if (in_young_gc_mode())
  1104     _last_young_gc_full = false;
  1107   // do that for any other surv rate groups
  1108   _short_lived_surv_rate_group->stop_adding_regions();
  1109   size_t short_lived_so_length = _young_list_so_prefix_length;
  1110   _short_lived_surv_rate_group->record_scan_only_prefix(short_lived_so_length);
  1111   tag_scan_only(short_lived_so_length);
  1113   if (G1UseSurvivorSpaces) {
  1114     _survivors_age_table.clear();
  1117   assert( verify_young_ages(), "region age verification" );
  1120 void G1CollectorPolicy::tag_scan_only(size_t short_lived_scan_only_length) {
  1121   // done in a way that it can be extended for other surv rate groups too...
  1123   HeapRegion* head = _g1->young_list_first_region();
  1124   bool finished_short_lived = (short_lived_scan_only_length == 0);
  1126   if (finished_short_lived)
  1127     return;
  1129   for (HeapRegion* curr = head;
  1130        curr != NULL;
  1131        curr = curr->get_next_young_region()) {
  1132     SurvRateGroup* surv_rate_group = curr->surv_rate_group();
  1133     int age = curr->age_in_surv_rate_group();
  1135     if (surv_rate_group == _short_lived_surv_rate_group) {
  1136       if ((size_t)age < short_lived_scan_only_length)
  1137         curr->set_scan_only();
  1138       else
  1139         finished_short_lived = true;
  1143     if (finished_short_lived)
  1144       return;
  1147   guarantee( false, "we should never reach here" );
  1150 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
  1151   _mark_closure_time_ms = mark_closure_time_ms;
  1154 void G1CollectorPolicy::record_concurrent_mark_init_start() {
  1155   _mark_init_start_sec = os::elapsedTime();
  1156   guarantee(!in_young_gc_mode(), "should not do be here in young GC mode");
  1159 void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double
  1160                                                    mark_init_elapsed_time_ms) {
  1161   _during_marking = true;
  1162   _should_initiate_conc_mark = false;
  1163   _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
  1166 void G1CollectorPolicy::record_concurrent_mark_init_end() {
  1167   double end_time_sec = os::elapsedTime();
  1168   double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
  1169   _concurrent_mark_init_times_ms->add(elapsed_time_ms);
  1170   record_concurrent_mark_init_end_pre(elapsed_time_ms);
  1172   _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true);
  1175 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
  1176   _mark_remark_start_sec = os::elapsedTime();
  1177   _during_marking = false;
  1180 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
  1181   double end_time_sec = os::elapsedTime();
  1182   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
  1183   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
  1184   _cur_mark_stop_world_time_ms += elapsed_time_ms;
  1185   _prev_collection_pause_end_ms += elapsed_time_ms;
  1187   _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
  1190 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
  1191   _mark_cleanup_start_sec = os::elapsedTime();
  1194 void
  1195 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
  1196                                                       size_t max_live_bytes) {
  1197   record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
  1198   record_concurrent_mark_cleanup_end_work2();
  1201 void
  1202 G1CollectorPolicy::
  1203 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
  1204                                          size_t max_live_bytes) {
  1205   if (_n_marks < 2) _n_marks++;
  1206   if (G1PolicyVerbose > 0)
  1207     gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB "
  1208                            " (of " SIZE_FORMAT " MB heap).",
  1209                            max_live_bytes/M, _g1->capacity()/M);
  1212 // The important thing about this is that it includes "os::elapsedTime".
  1213 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
  1214   double end_time_sec = os::elapsedTime();
  1215   double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
  1216   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
  1217   _cur_mark_stop_world_time_ms += elapsed_time_ms;
  1218   _prev_collection_pause_end_ms += elapsed_time_ms;
  1220   _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
  1222   _num_markings++;
  1224   // We did a marking, so reset the "since_last_mark" variables.
  1225   double considerConcMarkCost = 1.0;
  1226   // If there are available processors, concurrent activity is free...
  1227   if (Threads::number_of_non_daemon_threads() * 2 <
  1228       os::active_processor_count()) {
  1229     considerConcMarkCost = 0.0;
  1231   _n_pauses_at_mark_end = _n_pauses;
  1232   _n_marks_since_last_pause++;
  1233   _conc_mark_initiated = false;
  1236 void
  1237 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
  1238   if (in_young_gc_mode()) {
  1239     _should_revert_to_full_young_gcs = false;
  1240     _last_full_young_gc = true;
  1241     _in_marking_window = false;
  1242     if (adaptive_young_list_length())
  1243       calculate_young_list_target_config();
  1247 void G1CollectorPolicy::record_concurrent_pause() {
  1248   if (_stop_world_start > 0.0) {
  1249     double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
  1250     _all_yield_times_ms->add(yield_ms);
  1254 void G1CollectorPolicy::record_concurrent_pause_end() {
  1257 void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() {
  1258   _cur_CH_strong_roots_end_sec = os::elapsedTime();
  1259   _cur_CH_strong_roots_dur_ms =
  1260     (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0;
  1263 void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() {
  1264   _cur_G1_strong_roots_end_sec = os::elapsedTime();
  1265   _cur_G1_strong_roots_dur_ms =
  1266     (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0;
  1269 template<class T>
  1270 T sum_of(T* sum_arr, int start, int n, int N) {
  1271   T sum = (T)0;
  1272   for (int i = 0; i < n; i++) {
  1273     int j = (start + i) % N;
  1274     sum += sum_arr[j];
  1276   return sum;
  1279 void G1CollectorPolicy::print_par_stats (int level,
  1280                                          const char* str,
  1281                                          double* data,
  1282                                          bool summary) {
  1283   double min = data[0], max = data[0];
  1284   double total = 0.0;
  1285   int j;
  1286   for (j = 0; j < level; ++j)
  1287     gclog_or_tty->print("   ");
  1288   gclog_or_tty->print("[%s (ms):", str);
  1289   for (uint i = 0; i < ParallelGCThreads; ++i) {
  1290     double val = data[i];
  1291     if (val < min)
  1292       min = val;
  1293     if (val > max)
  1294       max = val;
  1295     total += val;
  1296     gclog_or_tty->print("  %3.1lf", val);
  1298   if (summary) {
  1299     gclog_or_tty->print_cr("");
  1300     double avg = total / (double) ParallelGCThreads;
  1301     gclog_or_tty->print(" ");
  1302     for (j = 0; j < level; ++j)
  1303       gclog_or_tty->print("   ");
  1304     gclog_or_tty->print("Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf",
  1305                         avg, min, max);
  1307   gclog_or_tty->print_cr("]");
  1310 void G1CollectorPolicy::print_par_buffers (int level,
  1311                                          const char* str,
  1312                                          double* data,
  1313                                          bool summary) {
  1314   double min = data[0], max = data[0];
  1315   double total = 0.0;
  1316   int j;
  1317   for (j = 0; j < level; ++j)
  1318     gclog_or_tty->print("   ");
  1319   gclog_or_tty->print("[%s :", str);
  1320   for (uint i = 0; i < ParallelGCThreads; ++i) {
  1321     double val = data[i];
  1322     if (val < min)
  1323       min = val;
  1324     if (val > max)
  1325       max = val;
  1326     total += val;
  1327     gclog_or_tty->print(" %d", (int) val);
  1329   if (summary) {
  1330     gclog_or_tty->print_cr("");
  1331     double avg = total / (double) ParallelGCThreads;
  1332     gclog_or_tty->print(" ");
  1333     for (j = 0; j < level; ++j)
  1334       gclog_or_tty->print("   ");
  1335     gclog_or_tty->print("Sum: %d, Avg: %d, Min: %d, Max: %d",
  1336                (int)total, (int)avg, (int)min, (int)max);
  1338   gclog_or_tty->print_cr("]");
  1341 void G1CollectorPolicy::print_stats (int level,
  1342                                      const char* str,
  1343                                      double value) {
  1344   for (int j = 0; j < level; ++j)
  1345     gclog_or_tty->print("   ");
  1346   gclog_or_tty->print_cr("[%s: %5.1lf ms]", str, value);
  1349 void G1CollectorPolicy::print_stats (int level,
  1350                                      const char* str,
  1351                                      int value) {
  1352   for (int j = 0; j < level; ++j)
  1353     gclog_or_tty->print("   ");
  1354   gclog_or_tty->print_cr("[%s: %d]", str, value);
  1357 double G1CollectorPolicy::avg_value (double* data) {
  1358   if (ParallelGCThreads > 0) {
  1359     double ret = 0.0;
  1360     for (uint i = 0; i < ParallelGCThreads; ++i)
  1361       ret += data[i];
  1362     return ret / (double) ParallelGCThreads;
  1363   } else {
  1364     return data[0];
  1368 double G1CollectorPolicy::max_value (double* data) {
  1369   if (ParallelGCThreads > 0) {
  1370     double ret = data[0];
  1371     for (uint i = 1; i < ParallelGCThreads; ++i)
  1372       if (data[i] > ret)
  1373         ret = data[i];
  1374     return ret;
  1375   } else {
  1376     return data[0];
  1380 double G1CollectorPolicy::sum_of_values (double* data) {
  1381   if (ParallelGCThreads > 0) {
  1382     double sum = 0.0;
  1383     for (uint i = 0; i < ParallelGCThreads; i++)
  1384       sum += data[i];
  1385     return sum;
  1386   } else {
  1387     return data[0];
  1391 double G1CollectorPolicy::max_sum (double* data1,
  1392                                    double* data2) {
  1393   double ret = data1[0] + data2[0];
  1395   if (ParallelGCThreads > 0) {
  1396     for (uint i = 1; i < ParallelGCThreads; ++i) {
  1397       double data = data1[i] + data2[i];
  1398       if (data > ret)
  1399         ret = data;
  1402   return ret;
  1405 // Anything below that is considered to be zero
  1406 #define MIN_TIMER_GRANULARITY 0.0000001
  1408 void G1CollectorPolicy::record_collection_pause_end(bool abandoned) {
  1409   double end_time_sec = os::elapsedTime();
  1410   double elapsed_ms = _last_pause_time_ms;
  1411   bool parallel = ParallelGCThreads > 0;
  1412   double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0;
  1413   size_t rs_size =
  1414     _cur_collection_pause_used_regions_at_start - collection_set_size();
  1415   size_t cur_used_bytes = _g1->used();
  1416   assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
  1417   bool last_pause_included_initial_mark = false;
  1418   bool update_stats = !abandoned && !_g1->evacuation_failed();
  1420 #ifndef PRODUCT
  1421   if (G1YoungSurvRateVerbose) {
  1422     gclog_or_tty->print_cr("");
  1423     _short_lived_surv_rate_group->print();
  1424     // do that for any other surv rate groups too
  1426 #endif // PRODUCT
  1428   if (in_young_gc_mode()) {
  1429     last_pause_included_initial_mark = _should_initiate_conc_mark;
  1430     if (last_pause_included_initial_mark)
  1431       record_concurrent_mark_init_end_pre(0.0);
  1433     size_t min_used_targ =
  1434       (_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta);
  1436     if (cur_used_bytes > min_used_targ) {
  1437       if (cur_used_bytes <= _prev_collection_pause_used_at_end_bytes) {
  1438       } else if (!_g1->mark_in_progress() && !_last_full_young_gc) {
  1439         _should_initiate_conc_mark = true;
  1443     _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
  1446   _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
  1447                           end_time_sec, false);
  1449   guarantee(_cur_collection_pause_used_regions_at_start >=
  1450             collection_set_size(),
  1451             "Negative RS size?");
  1453   // This assert is exempted when we're doing parallel collection pauses,
  1454   // because the fragmentation caused by the parallel GC allocation buffers
  1455   // can lead to more memory being used during collection than was used
  1456   // before. Best leave this out until the fragmentation problem is fixed.
  1457   // Pauses in which evacuation failed can also lead to negative
  1458   // collections, since no space is reclaimed from a region containing an
  1459   // object whose evacuation failed.
  1460   // Further, we're now always doing parallel collection.  But I'm still
  1461   // leaving this here as a placeholder for a more precise assertion later.
  1462   // (DLD, 10/05.)
  1463   assert((true || parallel) // Always using GC LABs now.
  1464          || _g1->evacuation_failed()
  1465          || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
  1466          "Negative collection");
  1468   size_t freed_bytes =
  1469     _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
  1470   size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
  1471   double survival_fraction =
  1472     (double)surviving_bytes/
  1473     (double)_collection_set_bytes_used_before;
  1475   _n_pauses++;
  1477   if (update_stats) {
  1478     _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms);
  1479     _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms);
  1480     _recent_evac_times_ms->add(evac_ms);
  1481     _recent_pause_times_ms->add(elapsed_ms);
  1483     _recent_rs_sizes->add(rs_size);
  1485     // We exempt parallel collection from this check because Alloc Buffer
  1486     // fragmentation can produce negative collections.  Same with evac
  1487     // failure.
  1488     // Further, we're now always doing parallel collection.  But I'm still
  1489     // leaving this here as a placeholder for a more precise assertion later.
  1490     // (DLD, 10/05.
  1491     assert((true || parallel)
  1492            || _g1->evacuation_failed()
  1493            || surviving_bytes <= _collection_set_bytes_used_before,
  1494            "Or else negative collection!");
  1495     _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
  1496     _recent_CS_bytes_surviving->add(surviving_bytes);
  1498     // this is where we update the allocation rate of the application
  1499     double app_time_ms =
  1500       (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
  1501     if (app_time_ms < MIN_TIMER_GRANULARITY) {
  1502       // This usually happens due to the timer not having the required
  1503       // granularity. Some Linuxes are the usual culprits.
  1504       // We'll just set it to something (arbitrarily) small.
  1505       app_time_ms = 1.0;
  1507     size_t regions_allocated =
  1508       (_region_num_young - _prev_region_num_young) +
  1509       (_region_num_tenured - _prev_region_num_tenured);
  1510     double alloc_rate_ms = (double) regions_allocated / app_time_ms;
  1511     _alloc_rate_ms_seq->add(alloc_rate_ms);
  1512     _prev_region_num_young   = _region_num_young;
  1513     _prev_region_num_tenured = _region_num_tenured;
  1515     double interval_ms =
  1516       (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
  1517     update_recent_gc_times(end_time_sec, elapsed_ms);
  1518     _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
  1519     if (recent_avg_pause_time_ratio() < 0.0 ||
  1520         (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
  1521 #ifndef PRODUCT
  1522       // Dump info to allow post-facto debugging
  1523       gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
  1524       gclog_or_tty->print_cr("-------------------------------------------");
  1525       gclog_or_tty->print_cr("Recent GC Times (ms):");
  1526       _recent_gc_times_ms->dump();
  1527       gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
  1528       _recent_prev_end_times_for_all_gcs_sec->dump();
  1529       gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
  1530                              _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
  1531       // In debug mode, terminate the JVM if the user wants to debug at this point.
  1532       assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
  1533 #endif  // !PRODUCT
  1534       // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
  1535       // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
  1536       if (_recent_avg_pause_time_ratio < 0.0) {
  1537         _recent_avg_pause_time_ratio = 0.0;
  1538       } else {
  1539         assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
  1540         _recent_avg_pause_time_ratio = 1.0;
  1545   if (G1PolicyVerbose > 1) {
  1546     gclog_or_tty->print_cr("   Recording collection pause(%d)", _n_pauses);
  1549   PauseSummary* summary;
  1550   if (abandoned) {
  1551     summary = _abandoned_summary;
  1552   } else {
  1553     summary = _summary;
  1556   double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
  1557   double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
  1558   double scan_only_time = avg_value(_par_last_scan_only_times_ms);
  1559   double scan_only_regions_scanned =
  1560     sum_of_values(_par_last_scan_only_regions_scanned);
  1561   double update_rs_time = avg_value(_par_last_update_rs_times_ms);
  1562   double update_rs_processed_buffers =
  1563     sum_of_values(_par_last_update_rs_processed_buffers);
  1564   double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
  1565   double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
  1566   double termination_time = avg_value(_par_last_termination_times_ms);
  1568   double parallel_other_time = _cur_collection_par_time_ms -
  1569     (update_rs_time + ext_root_scan_time + mark_stack_scan_time +
  1570      scan_only_time + scan_rs_time + obj_copy_time + termination_time);
  1571   if (update_stats) {
  1572     MainBodySummary* body_summary = summary->main_body_summary();
  1573     guarantee(body_summary != NULL, "should not be null!");
  1575     if (_satb_drain_time_set)
  1576       body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
  1577     else
  1578       body_summary->record_satb_drain_time_ms(0.0);
  1579     body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
  1580     body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
  1581     body_summary->record_scan_only_time_ms(scan_only_time);
  1582     body_summary->record_update_rs_time_ms(update_rs_time);
  1583     body_summary->record_scan_rs_time_ms(scan_rs_time);
  1584     body_summary->record_obj_copy_time_ms(obj_copy_time);
  1585     if (parallel) {
  1586       body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
  1587       body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
  1588       body_summary->record_termination_time_ms(termination_time);
  1589       body_summary->record_parallel_other_time_ms(parallel_other_time);
  1591     body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
  1594   if (G1PolicyVerbose > 1) {
  1595     gclog_or_tty->print_cr("      ET: %10.6f ms           (avg: %10.6f ms)\n"
  1596                            "        CH Strong: %10.6f ms    (avg: %10.6f ms)\n"
  1597                            "        G1 Strong: %10.6f ms    (avg: %10.6f ms)\n"
  1598                            "        Evac:      %10.6f ms    (avg: %10.6f ms)\n"
  1599                            "       ET-RS:  %10.6f ms      (avg: %10.6f ms)\n"
  1600                            "      |RS|: " SIZE_FORMAT,
  1601                            elapsed_ms, recent_avg_time_for_pauses_ms(),
  1602                            _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(),
  1603                            _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(),
  1604                            evac_ms, recent_avg_time_for_evac_ms(),
  1605                            scan_rs_time,
  1606                            recent_avg_time_for_pauses_ms() -
  1607                            recent_avg_time_for_G1_strong_ms(),
  1608                            rs_size);
  1610     gclog_or_tty->print_cr("       Used at start: " SIZE_FORMAT"K"
  1611                            "       At end " SIZE_FORMAT "K\n"
  1612                            "       garbage      : " SIZE_FORMAT "K"
  1613                            "       of     " SIZE_FORMAT "K\n"
  1614                            "       survival     : %6.2f%%  (%6.2f%% avg)",
  1615                            _cur_collection_pause_used_at_start_bytes/K,
  1616                            _g1->used()/K, freed_bytes/K,
  1617                            _collection_set_bytes_used_before/K,
  1618                            survival_fraction*100.0,
  1619                            recent_avg_survival_fraction()*100.0);
  1620     gclog_or_tty->print_cr("       Recent %% gc pause time: %6.2f",
  1621                            recent_avg_pause_time_ratio() * 100.0);
  1624   double other_time_ms = elapsed_ms;
  1626   if (!abandoned) {
  1627     if (_satb_drain_time_set)
  1628       other_time_ms -= _cur_satb_drain_time_ms;
  1630     if (parallel)
  1631       other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
  1632     else
  1633       other_time_ms -=
  1634         update_rs_time +
  1635         ext_root_scan_time + mark_stack_scan_time + scan_only_time +
  1636         scan_rs_time + obj_copy_time;
  1639   if (PrintGCDetails) {
  1640     gclog_or_tty->print_cr("%s%s, %1.8lf secs]",
  1641                            abandoned ? " (abandoned)" : "",
  1642                            (last_pause_included_initial_mark) ? " (initial-mark)" : "",
  1643                            elapsed_ms / 1000.0);
  1645     if (!abandoned) {
  1646       if (_satb_drain_time_set) {
  1647         print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
  1649       if (_last_satb_drain_processed_buffers >= 0) {
  1650         print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
  1652       if (parallel) {
  1653         print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
  1654         print_par_stats(2, "Update RS (Start)", _par_last_update_rs_start_times_ms, false);
  1655         print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
  1656         print_par_buffers(3, "Processed Buffers",
  1657                           _par_last_update_rs_processed_buffers, true);
  1658         print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
  1659         print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
  1660         print_par_stats(2, "Scan-Only Scanning", _par_last_scan_only_times_ms);
  1661         print_par_buffers(3, "Scan-Only Regions",
  1662                           _par_last_scan_only_regions_scanned, true);
  1663         print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
  1664         print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
  1665         print_par_stats(2, "Termination", _par_last_termination_times_ms);
  1666         print_stats(2, "Other", parallel_other_time);
  1667         print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
  1668       } else {
  1669         print_stats(1, "Update RS", update_rs_time);
  1670         print_stats(2, "Processed Buffers",
  1671                     (int)update_rs_processed_buffers);
  1672         print_stats(1, "Ext Root Scanning", ext_root_scan_time);
  1673         print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
  1674         print_stats(1, "Scan-Only Scanning", scan_only_time);
  1675         print_stats(1, "Scan RS", scan_rs_time);
  1676         print_stats(1, "Object Copying", obj_copy_time);
  1679 #ifndef PRODUCT
  1680     print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
  1681     print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
  1682     print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
  1683     print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
  1684     if (_num_cc_clears > 0) {
  1685       print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
  1687 #endif
  1688     print_stats(1, "Other", other_time_ms);
  1689     for (int i = 0; i < _aux_num; ++i) {
  1690       if (_cur_aux_times_set[i]) {
  1691         char buffer[96];
  1692         sprintf(buffer, "Aux%d", i);
  1693         print_stats(1, buffer, _cur_aux_times_ms[i]);
  1697   if (PrintGCDetails)
  1698     gclog_or_tty->print("   [");
  1699   if (PrintGC || PrintGCDetails)
  1700     _g1->print_size_transition(gclog_or_tty,
  1701                                _cur_collection_pause_used_at_start_bytes,
  1702                                _g1->used(), _g1->capacity());
  1703   if (PrintGCDetails)
  1704     gclog_or_tty->print_cr("]");
  1706   _all_pause_times_ms->add(elapsed_ms);
  1707   if (update_stats) {
  1708     summary->record_total_time_ms(elapsed_ms);
  1709     summary->record_other_time_ms(other_time_ms);
  1711   for (int i = 0; i < _aux_num; ++i)
  1712     if (_cur_aux_times_set[i])
  1713       _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
  1715   // Reset marks-between-pauses counter.
  1716   _n_marks_since_last_pause = 0;
  1718   // Update the efficiency-since-mark vars.
  1719   double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
  1720   if (elapsed_ms < MIN_TIMER_GRANULARITY) {
  1721     // This usually happens due to the timer not having the required
  1722     // granularity. Some Linuxes are the usual culprits.
  1723     // We'll just set it to something (arbitrarily) small.
  1724     proc_ms = 1.0;
  1726   double cur_efficiency = (double) freed_bytes / proc_ms;
  1728   bool new_in_marking_window = _in_marking_window;
  1729   bool new_in_marking_window_im = false;
  1730   if (_should_initiate_conc_mark) {
  1731     new_in_marking_window = true;
  1732     new_in_marking_window_im = true;
  1735   if (in_young_gc_mode()) {
  1736     if (_last_full_young_gc) {
  1737       set_full_young_gcs(false);
  1738       _last_full_young_gc = false;
  1741     if ( !_last_young_gc_full ) {
  1742       if ( _should_revert_to_full_young_gcs ||
  1743            _known_garbage_ratio < 0.05 ||
  1744            (adaptive_young_list_length() &&
  1745            (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) {
  1746         set_full_young_gcs(true);
  1749     _should_revert_to_full_young_gcs = false;
  1751     if (_last_young_gc_full && !_during_marking)
  1752       _young_gc_eff_seq->add(cur_efficiency);
  1755   _short_lived_surv_rate_group->start_adding_regions();
  1756   // do that for any other surv rate groupsx
  1758   // <NEW PREDICTION>
  1760   if (update_stats) {
  1761     double pause_time_ms = elapsed_ms;
  1763     size_t diff = 0;
  1764     if (_max_pending_cards >= _pending_cards)
  1765       diff = _max_pending_cards - _pending_cards;
  1766     _pending_card_diff_seq->add((double) diff);
  1768     double cost_per_card_ms = 0.0;
  1769     if (_pending_cards > 0) {
  1770       cost_per_card_ms = update_rs_time / (double) _pending_cards;
  1771       _cost_per_card_ms_seq->add(cost_per_card_ms);
  1774     double cost_per_scan_only_region_ms = 0.0;
  1775     if (scan_only_regions_scanned > 0.0) {
  1776       cost_per_scan_only_region_ms =
  1777         scan_only_time / scan_only_regions_scanned;
  1778       if (_in_marking_window_im)
  1779         _cost_per_scan_only_region_ms_during_cm_seq->add(cost_per_scan_only_region_ms);
  1780       else
  1781         _cost_per_scan_only_region_ms_seq->add(cost_per_scan_only_region_ms);
  1784     size_t cards_scanned = _g1->cards_scanned();
  1786     double cost_per_entry_ms = 0.0;
  1787     if (cards_scanned > 10) {
  1788       cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
  1789       if (_last_young_gc_full)
  1790         _cost_per_entry_ms_seq->add(cost_per_entry_ms);
  1791       else
  1792         _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
  1795     if (_max_rs_lengths > 0) {
  1796       double cards_per_entry_ratio =
  1797         (double) cards_scanned / (double) _max_rs_lengths;
  1798       if (_last_young_gc_full)
  1799         _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
  1800       else
  1801         _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
  1804     size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
  1805     if (rs_length_diff >= 0)
  1806       _rs_length_diff_seq->add((double) rs_length_diff);
  1808     size_t copied_bytes = surviving_bytes;
  1809     double cost_per_byte_ms = 0.0;
  1810     if (copied_bytes > 0) {
  1811       cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
  1812       if (_in_marking_window)
  1813         _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
  1814       else
  1815         _cost_per_byte_ms_seq->add(cost_per_byte_ms);
  1818     double all_other_time_ms = pause_time_ms -
  1819       (update_rs_time + scan_only_time + scan_rs_time + obj_copy_time +
  1820        _mark_closure_time_ms + termination_time);
  1822     double young_other_time_ms = 0.0;
  1823     if (_recorded_young_regions > 0) {
  1824       young_other_time_ms =
  1825         _recorded_young_cset_choice_time_ms +
  1826         _recorded_young_free_cset_time_ms;
  1827       _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
  1828                                              (double) _recorded_young_regions);
  1830     double non_young_other_time_ms = 0.0;
  1831     if (_recorded_non_young_regions > 0) {
  1832       non_young_other_time_ms =
  1833         _recorded_non_young_cset_choice_time_ms +
  1834         _recorded_non_young_free_cset_time_ms;
  1836       _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
  1837                                          (double) _recorded_non_young_regions);
  1840     double constant_other_time_ms = all_other_time_ms -
  1841       (young_other_time_ms + non_young_other_time_ms);
  1842     _constant_other_time_ms_seq->add(constant_other_time_ms);
  1844     double survival_ratio = 0.0;
  1845     if (_bytes_in_collection_set_before_gc > 0) {
  1846       survival_ratio = (double) bytes_in_to_space_during_gc() /
  1847         (double) _bytes_in_collection_set_before_gc;
  1850     _pending_cards_seq->add((double) _pending_cards);
  1851     _scanned_cards_seq->add((double) cards_scanned);
  1852     _rs_lengths_seq->add((double) _max_rs_lengths);
  1854     double expensive_region_limit_ms =
  1855       (double) MaxGCPauseMillis - predict_constant_other_time_ms();
  1856     if (expensive_region_limit_ms < 0.0) {
  1857       // this means that the other time was predicted to be longer than
  1858       // than the max pause time
  1859       expensive_region_limit_ms = (double) MaxGCPauseMillis;
  1861     _expensive_region_limit_ms = expensive_region_limit_ms;
  1863     if (PREDICTIONS_VERBOSE) {
  1864       gclog_or_tty->print_cr("");
  1865       gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
  1866                     "REGIONS %d %d %d %d "
  1867                     "PENDING_CARDS %d %d "
  1868                     "CARDS_SCANNED %d %d "
  1869                     "RS_LENGTHS %d %d "
  1870                     "SCAN_ONLY_SCAN %1.6lf %1.6lf "
  1871                     "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
  1872                     "SURVIVAL_RATIO %1.6lf %1.6lf "
  1873                     "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
  1874                     "OTHER_YOUNG %1.6lf %1.6lf "
  1875                     "OTHER_NON_YOUNG %1.6lf %1.6lf "
  1876                     "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
  1877                     "ELAPSED %1.6lf %1.6lf ",
  1878                     _cur_collection_start_sec,
  1879                     (!_last_young_gc_full) ? 2 :
  1880                     (last_pause_included_initial_mark) ? 1 : 0,
  1881                     _recorded_region_num,
  1882                     _recorded_young_regions,
  1883                     _recorded_scan_only_regions,
  1884                     _recorded_non_young_regions,
  1885                     _predicted_pending_cards, _pending_cards,
  1886                     _predicted_cards_scanned, cards_scanned,
  1887                     _predicted_rs_lengths, _max_rs_lengths,
  1888                     _predicted_scan_only_scan_time_ms, scan_only_time,
  1889                     _predicted_rs_update_time_ms, update_rs_time,
  1890                     _predicted_rs_scan_time_ms, scan_rs_time,
  1891                     _predicted_survival_ratio, survival_ratio,
  1892                     _predicted_object_copy_time_ms, obj_copy_time,
  1893                     _predicted_constant_other_time_ms, constant_other_time_ms,
  1894                     _predicted_young_other_time_ms, young_other_time_ms,
  1895                     _predicted_non_young_other_time_ms,
  1896                     non_young_other_time_ms,
  1897                     _vtime_diff_ms, termination_time,
  1898                     _predicted_pause_time_ms, elapsed_ms);
  1901     if (G1PolicyVerbose > 0) {
  1902       gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
  1903                     _predicted_pause_time_ms,
  1904                     (_within_target) ? "within" : "outside",
  1905                     elapsed_ms);
  1910   _in_marking_window = new_in_marking_window;
  1911   _in_marking_window_im = new_in_marking_window_im;
  1912   _free_regions_at_end_of_collection = _g1->free_regions();
  1913   _scan_only_regions_at_end_of_collection = _g1->young_list_length();
  1914   calculate_young_list_min_length();
  1915   calculate_young_list_target_config();
  1917   // </NEW PREDICTION>
  1919   _target_pause_time_ms = -1.0;
  1922 // <NEW PREDICTION>
  1924 double
  1925 G1CollectorPolicy::
  1926 predict_young_collection_elapsed_time_ms(size_t adjustment) {
  1927   guarantee( adjustment == 0 || adjustment == 1, "invariant" );
  1929   G1CollectedHeap* g1h = G1CollectedHeap::heap();
  1930   size_t young_num = g1h->young_list_length();
  1931   if (young_num == 0)
  1932     return 0.0;
  1934   young_num += adjustment;
  1935   size_t pending_cards = predict_pending_cards();
  1936   size_t rs_lengths = g1h->young_list_sampled_rs_lengths() +
  1937                       predict_rs_length_diff();
  1938   size_t card_num;
  1939   if (full_young_gcs())
  1940     card_num = predict_young_card_num(rs_lengths);
  1941   else
  1942     card_num = predict_non_young_card_num(rs_lengths);
  1943   size_t young_byte_size = young_num * HeapRegion::GrainBytes;
  1944   double accum_yg_surv_rate =
  1945     _short_lived_surv_rate_group->accum_surv_rate(adjustment);
  1947   size_t bytes_to_copy =
  1948     (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
  1950   return
  1951     predict_rs_update_time_ms(pending_cards) +
  1952     predict_rs_scan_time_ms(card_num) +
  1953     predict_object_copy_time_ms(bytes_to_copy) +
  1954     predict_young_other_time_ms(young_num) +
  1955     predict_constant_other_time_ms();
  1958 double
  1959 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
  1960   size_t rs_length = predict_rs_length_diff();
  1961   size_t card_num;
  1962   if (full_young_gcs())
  1963     card_num = predict_young_card_num(rs_length);
  1964   else
  1965     card_num = predict_non_young_card_num(rs_length);
  1966   return predict_base_elapsed_time_ms(pending_cards, card_num);
  1969 double
  1970 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
  1971                                                 size_t scanned_cards) {
  1972   return
  1973     predict_rs_update_time_ms(pending_cards) +
  1974     predict_rs_scan_time_ms(scanned_cards) +
  1975     predict_constant_other_time_ms();
  1978 double
  1979 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
  1980                                                   bool young) {
  1981   size_t rs_length = hr->rem_set()->occupied();
  1982   size_t card_num;
  1983   if (full_young_gcs())
  1984     card_num = predict_young_card_num(rs_length);
  1985   else
  1986     card_num = predict_non_young_card_num(rs_length);
  1987   size_t bytes_to_copy = predict_bytes_to_copy(hr);
  1989   double region_elapsed_time_ms =
  1990     predict_rs_scan_time_ms(card_num) +
  1991     predict_object_copy_time_ms(bytes_to_copy);
  1993   if (young)
  1994     region_elapsed_time_ms += predict_young_other_time_ms(1);
  1995   else
  1996     region_elapsed_time_ms += predict_non_young_other_time_ms(1);
  1998   return region_elapsed_time_ms;
  2001 size_t
  2002 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
  2003   size_t bytes_to_copy;
  2004   if (hr->is_marked())
  2005     bytes_to_copy = hr->max_live_bytes();
  2006   else {
  2007     guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
  2008                "invariant" );
  2009     int age = hr->age_in_surv_rate_group();
  2010     double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
  2011     bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
  2014   return bytes_to_copy;
  2017 void
  2018 G1CollectorPolicy::start_recording_regions() {
  2019   _recorded_rs_lengths            = 0;
  2020   _recorded_scan_only_regions     = 0;
  2021   _recorded_young_regions         = 0;
  2022   _recorded_non_young_regions     = 0;
  2024 #if PREDICTIONS_VERBOSE
  2025   _predicted_rs_lengths           = 0;
  2026   _predicted_cards_scanned        = 0;
  2028   _recorded_marked_bytes          = 0;
  2029   _recorded_young_bytes           = 0;
  2030   _predicted_bytes_to_copy        = 0;
  2031 #endif // PREDICTIONS_VERBOSE
  2034 void
  2035 G1CollectorPolicy::record_cset_region(HeapRegion* hr, bool young) {
  2036   if (young) {
  2037     ++_recorded_young_regions;
  2038   } else {
  2039     ++_recorded_non_young_regions;
  2041 #if PREDICTIONS_VERBOSE
  2042   if (young) {
  2043     _recorded_young_bytes += hr->used();
  2044   } else {
  2045     _recorded_marked_bytes += hr->max_live_bytes();
  2047   _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
  2048 #endif // PREDICTIONS_VERBOSE
  2050   size_t rs_length = hr->rem_set()->occupied();
  2051   _recorded_rs_lengths += rs_length;
  2054 void
  2055 G1CollectorPolicy::record_scan_only_regions(size_t scan_only_length) {
  2056   _recorded_scan_only_regions = scan_only_length;
  2059 void
  2060 G1CollectorPolicy::end_recording_regions() {
  2061 #if PREDICTIONS_VERBOSE
  2062   _predicted_pending_cards = predict_pending_cards();
  2063   _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
  2064   if (full_young_gcs())
  2065     _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
  2066   else
  2067     _predicted_cards_scanned +=
  2068       predict_non_young_card_num(_predicted_rs_lengths);
  2069   _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
  2071   _predicted_scan_only_scan_time_ms =
  2072     predict_scan_only_time_ms(_recorded_scan_only_regions);
  2073   _predicted_rs_update_time_ms =
  2074     predict_rs_update_time_ms(_g1->pending_card_num());
  2075   _predicted_rs_scan_time_ms =
  2076     predict_rs_scan_time_ms(_predicted_cards_scanned);
  2077   _predicted_object_copy_time_ms =
  2078     predict_object_copy_time_ms(_predicted_bytes_to_copy);
  2079   _predicted_constant_other_time_ms =
  2080     predict_constant_other_time_ms();
  2081   _predicted_young_other_time_ms =
  2082     predict_young_other_time_ms(_recorded_young_regions);
  2083   _predicted_non_young_other_time_ms =
  2084     predict_non_young_other_time_ms(_recorded_non_young_regions);
  2086   _predicted_pause_time_ms =
  2087     _predicted_scan_only_scan_time_ms +
  2088     _predicted_rs_update_time_ms +
  2089     _predicted_rs_scan_time_ms +
  2090     _predicted_object_copy_time_ms +
  2091     _predicted_constant_other_time_ms +
  2092     _predicted_young_other_time_ms +
  2093     _predicted_non_young_other_time_ms;
  2094 #endif // PREDICTIONS_VERBOSE
  2097 void G1CollectorPolicy::check_if_region_is_too_expensive(double
  2098                                                            predicted_time_ms) {
  2099   // I don't think we need to do this when in young GC mode since
  2100   // marking will be initiated next time we hit the soft limit anyway...
  2101   if (predicted_time_ms > _expensive_region_limit_ms) {
  2102     if (!in_young_gc_mode()) {
  2103         set_full_young_gcs(true);
  2104       _should_initiate_conc_mark = true;
  2105     } else
  2106       // no point in doing another partial one
  2107       _should_revert_to_full_young_gcs = true;
  2111 // </NEW PREDICTION>
  2114 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
  2115                                                double elapsed_ms) {
  2116   _recent_gc_times_ms->add(elapsed_ms);
  2117   _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
  2118   _prev_collection_pause_end_ms = end_time_sec * 1000.0;
  2121 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
  2122   if (_recent_pause_times_ms->num() == 0) return (double) MaxGCPauseMillis;
  2123   else return _recent_pause_times_ms->avg();
  2126 double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() {
  2127   if (_recent_CH_strong_roots_times_ms->num() == 0)
  2128     return (double)MaxGCPauseMillis/3.0;
  2129   else return _recent_CH_strong_roots_times_ms->avg();
  2132 double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() {
  2133   if (_recent_G1_strong_roots_times_ms->num() == 0)
  2134     return (double)MaxGCPauseMillis/3.0;
  2135   else return _recent_G1_strong_roots_times_ms->avg();
  2138 double G1CollectorPolicy::recent_avg_time_for_evac_ms() {
  2139   if (_recent_evac_times_ms->num() == 0) return (double)MaxGCPauseMillis/3.0;
  2140   else return _recent_evac_times_ms->avg();
  2143 int G1CollectorPolicy::number_of_recent_gcs() {
  2144   assert(_recent_CH_strong_roots_times_ms->num() ==
  2145          _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync");
  2146   assert(_recent_G1_strong_roots_times_ms->num() ==
  2147          _recent_evac_times_ms->num(), "Sequence out of sync");
  2148   assert(_recent_evac_times_ms->num() ==
  2149          _recent_pause_times_ms->num(), "Sequence out of sync");
  2150   assert(_recent_pause_times_ms->num() ==
  2151          _recent_CS_bytes_used_before->num(), "Sequence out of sync");
  2152   assert(_recent_CS_bytes_used_before->num() ==
  2153          _recent_CS_bytes_surviving->num(), "Sequence out of sync");
  2154   return _recent_pause_times_ms->num();
  2157 double G1CollectorPolicy::recent_avg_survival_fraction() {
  2158   return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
  2159                                            _recent_CS_bytes_used_before);
  2162 double G1CollectorPolicy::last_survival_fraction() {
  2163   return last_survival_fraction_work(_recent_CS_bytes_surviving,
  2164                                      _recent_CS_bytes_used_before);
  2167 double
  2168 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
  2169                                                      TruncatedSeq* before) {
  2170   assert(surviving->num() == before->num(), "Sequence out of sync");
  2171   if (before->sum() > 0.0) {
  2172       double recent_survival_rate = surviving->sum() / before->sum();
  2173       // We exempt parallel collection from this check because Alloc Buffer
  2174       // fragmentation can produce negative collections.
  2175       // Further, we're now always doing parallel collection.  But I'm still
  2176       // leaving this here as a placeholder for a more precise assertion later.
  2177       // (DLD, 10/05.)
  2178       assert((true || ParallelGCThreads > 0) ||
  2179              _g1->evacuation_failed() ||
  2180              recent_survival_rate <= 1.0, "Or bad frac");
  2181       return recent_survival_rate;
  2182   } else {
  2183     return 1.0; // Be conservative.
  2187 double
  2188 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
  2189                                                TruncatedSeq* before) {
  2190   assert(surviving->num() == before->num(), "Sequence out of sync");
  2191   if (surviving->num() > 0 && before->last() > 0.0) {
  2192     double last_survival_rate = surviving->last() / before->last();
  2193     // We exempt parallel collection from this check because Alloc Buffer
  2194     // fragmentation can produce negative collections.
  2195     // Further, we're now always doing parallel collection.  But I'm still
  2196     // leaving this here as a placeholder for a more precise assertion later.
  2197     // (DLD, 10/05.)
  2198     assert((true || ParallelGCThreads > 0) ||
  2199            last_survival_rate <= 1.0, "Or bad frac");
  2200     return last_survival_rate;
  2201   } else {
  2202     return 1.0;
  2206 static const int survival_min_obs = 5;
  2207 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
  2208 static const double min_survival_rate = 0.1;
  2210 double
  2211 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
  2212                                                            double latest) {
  2213   double res = avg;
  2214   if (number_of_recent_gcs() < survival_min_obs) {
  2215     res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
  2217   res = MAX2(res, latest);
  2218   res = MAX2(res, min_survival_rate);
  2219   // In the parallel case, LAB fragmentation can produce "negative
  2220   // collections"; so can evac failure.  Cap at 1.0
  2221   res = MIN2(res, 1.0);
  2222   return res;
  2225 size_t G1CollectorPolicy::expansion_amount() {
  2226   if ((int)(recent_avg_pause_time_ratio() * 100.0) > G1GCPercent) {
  2227     // We will double the existing space, or take
  2228     // G1ExpandByPercentOfAvailable % of the available expansion
  2229     // space, whichever is smaller, bounded below by a minimum
  2230     // expansion (unless that's all that's left.)
  2231     const size_t min_expand_bytes = 1*M;
  2232     size_t reserved_bytes = _g1->g1_reserved_obj_bytes();
  2233     size_t committed_bytes = _g1->capacity();
  2234     size_t uncommitted_bytes = reserved_bytes - committed_bytes;
  2235     size_t expand_bytes;
  2236     size_t expand_bytes_via_pct =
  2237       uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
  2238     expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
  2239     expand_bytes = MAX2(expand_bytes, min_expand_bytes);
  2240     expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
  2241     if (G1PolicyVerbose > 1) {
  2242       gclog_or_tty->print("Decided to expand: ratio = %5.2f, "
  2243                  "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n"
  2244                  "                   Answer = %d.\n",
  2245                  recent_avg_pause_time_ratio(),
  2246                  byte_size_in_proper_unit(committed_bytes),
  2247                  proper_unit_for_byte_size(committed_bytes),
  2248                  byte_size_in_proper_unit(uncommitted_bytes),
  2249                  proper_unit_for_byte_size(uncommitted_bytes),
  2250                  byte_size_in_proper_unit(expand_bytes_via_pct),
  2251                  proper_unit_for_byte_size(expand_bytes_via_pct),
  2252                  byte_size_in_proper_unit(expand_bytes),
  2253                  proper_unit_for_byte_size(expand_bytes));
  2255     return expand_bytes;
  2256   } else {
  2257     return 0;
  2261 void G1CollectorPolicy::note_start_of_mark_thread() {
  2262   _mark_thread_startup_sec = os::elapsedTime();
  2265 class CountCSClosure: public HeapRegionClosure {
  2266   G1CollectorPolicy* _g1_policy;
  2267 public:
  2268   CountCSClosure(G1CollectorPolicy* g1_policy) :
  2269     _g1_policy(g1_policy) {}
  2270   bool doHeapRegion(HeapRegion* r) {
  2271     _g1_policy->_bytes_in_collection_set_before_gc += r->used();
  2272     return false;
  2274 };
  2276 void G1CollectorPolicy::count_CS_bytes_used() {
  2277   CountCSClosure cs_closure(this);
  2278   _g1->collection_set_iterate(&cs_closure);
  2281 static void print_indent(int level) {
  2282   for (int j = 0; j < level+1; ++j)
  2283     gclog_or_tty->print("   ");
  2286 void G1CollectorPolicy::print_summary (int level,
  2287                                        const char* str,
  2288                                        NumberSeq* seq) const {
  2289   double sum = seq->sum();
  2290   print_indent(level);
  2291   gclog_or_tty->print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
  2292                 str, sum / 1000.0, seq->avg());
  2295 void G1CollectorPolicy::print_summary_sd (int level,
  2296                                           const char* str,
  2297                                           NumberSeq* seq) const {
  2298   print_summary(level, str, seq);
  2299   print_indent(level + 5);
  2300   gclog_or_tty->print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
  2301                 seq->num(), seq->sd(), seq->maximum());
  2304 void G1CollectorPolicy::check_other_times(int level,
  2305                                         NumberSeq* other_times_ms,
  2306                                         NumberSeq* calc_other_times_ms) const {
  2307   bool should_print = false;
  2309   double max_sum = MAX2(fabs(other_times_ms->sum()),
  2310                         fabs(calc_other_times_ms->sum()));
  2311   double min_sum = MIN2(fabs(other_times_ms->sum()),
  2312                         fabs(calc_other_times_ms->sum()));
  2313   double sum_ratio = max_sum / min_sum;
  2314   if (sum_ratio > 1.1) {
  2315     should_print = true;
  2316     print_indent(level + 1);
  2317     gclog_or_tty->print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
  2320   double max_avg = MAX2(fabs(other_times_ms->avg()),
  2321                         fabs(calc_other_times_ms->avg()));
  2322   double min_avg = MIN2(fabs(other_times_ms->avg()),
  2323                         fabs(calc_other_times_ms->avg()));
  2324   double avg_ratio = max_avg / min_avg;
  2325   if (avg_ratio > 1.1) {
  2326     should_print = true;
  2327     print_indent(level + 1);
  2328     gclog_or_tty->print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
  2331   if (other_times_ms->sum() < -0.01) {
  2332     print_indent(level + 1);
  2333     gclog_or_tty->print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
  2336   if (other_times_ms->avg() < -0.01) {
  2337     print_indent(level + 1);
  2338     gclog_or_tty->print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
  2341   if (calc_other_times_ms->sum() < -0.01) {
  2342     should_print = true;
  2343     print_indent(level + 1);
  2344     gclog_or_tty->print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
  2347   if (calc_other_times_ms->avg() < -0.01) {
  2348     should_print = true;
  2349     print_indent(level + 1);
  2350     gclog_or_tty->print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
  2353   if (should_print)
  2354     print_summary(level, "Other(Calc)", calc_other_times_ms);
  2357 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
  2358   bool parallel = ParallelGCThreads > 0;
  2359   MainBodySummary*    body_summary = summary->main_body_summary();
  2360   if (summary->get_total_seq()->num() > 0) {
  2361     print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
  2362     if (body_summary != NULL) {
  2363       print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
  2364       if (parallel) {
  2365         print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
  2366         print_summary(2, "Update RS", body_summary->get_update_rs_seq());
  2367         print_summary(2, "Ext Root Scanning",
  2368                       body_summary->get_ext_root_scan_seq());
  2369         print_summary(2, "Mark Stack Scanning",
  2370                       body_summary->get_mark_stack_scan_seq());
  2371         print_summary(2, "Scan-Only Scanning",
  2372                       body_summary->get_scan_only_seq());
  2373         print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
  2374         print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
  2375         print_summary(2, "Termination", body_summary->get_termination_seq());
  2376         print_summary(2, "Other", body_summary->get_parallel_other_seq());
  2378           NumberSeq* other_parts[] = {
  2379             body_summary->get_update_rs_seq(),
  2380             body_summary->get_ext_root_scan_seq(),
  2381             body_summary->get_mark_stack_scan_seq(),
  2382             body_summary->get_scan_only_seq(),
  2383             body_summary->get_scan_rs_seq(),
  2384             body_summary->get_obj_copy_seq(),
  2385             body_summary->get_termination_seq()
  2386           };
  2387           NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
  2388                                         7, other_parts);
  2389           check_other_times(2, body_summary->get_parallel_other_seq(),
  2390                             &calc_other_times_ms);
  2392         print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
  2393         print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
  2394       } else {
  2395         print_summary(1, "Update RS", body_summary->get_update_rs_seq());
  2396         print_summary(1, "Ext Root Scanning",
  2397                       body_summary->get_ext_root_scan_seq());
  2398         print_summary(1, "Mark Stack Scanning",
  2399                       body_summary->get_mark_stack_scan_seq());
  2400         print_summary(1, "Scan-Only Scanning",
  2401                       body_summary->get_scan_only_seq());
  2402         print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
  2403         print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
  2406     print_summary(1, "Other", summary->get_other_seq());
  2408       NumberSeq calc_other_times_ms;
  2409       if (body_summary != NULL) {
  2410         // not abandoned
  2411         if (parallel) {
  2412           // parallel
  2413           NumberSeq* other_parts[] = {
  2414             body_summary->get_satb_drain_seq(),
  2415             body_summary->get_parallel_seq(),
  2416             body_summary->get_clear_ct_seq()
  2417           };
  2418           calc_other_times_ms = NumberSeq(summary->get_total_seq(),
  2419                                           3, other_parts);
  2420         } else {
  2421           // serial
  2422           NumberSeq* other_parts[] = {
  2423             body_summary->get_satb_drain_seq(),
  2424             body_summary->get_update_rs_seq(),
  2425             body_summary->get_ext_root_scan_seq(),
  2426             body_summary->get_mark_stack_scan_seq(),
  2427             body_summary->get_scan_only_seq(),
  2428             body_summary->get_scan_rs_seq(),
  2429             body_summary->get_obj_copy_seq()
  2430           };
  2431           calc_other_times_ms = NumberSeq(summary->get_total_seq(),
  2432                                           7, other_parts);
  2434       } else {
  2435         // abandoned
  2436         calc_other_times_ms = NumberSeq();
  2438       check_other_times(1,  summary->get_other_seq(), &calc_other_times_ms);
  2440   } else {
  2441     print_indent(0);
  2442     gclog_or_tty->print_cr("none");
  2444   gclog_or_tty->print_cr("");
  2447 void
  2448 G1CollectorPolicy::print_abandoned_summary(PauseSummary* summary) const {
  2449   bool printed = false;
  2450   if (summary->get_total_seq()->num() > 0) {
  2451     printed = true;
  2452     print_summary(summary);
  2454   if (!printed) {
  2455     print_indent(0);
  2456     gclog_or_tty->print_cr("none");
  2457     gclog_or_tty->print_cr("");
  2461 void G1CollectorPolicy::print_tracing_info() const {
  2462   if (TraceGen0Time) {
  2463     gclog_or_tty->print_cr("ALL PAUSES");
  2464     print_summary_sd(0, "Total", _all_pause_times_ms);
  2465     gclog_or_tty->print_cr("");
  2466     gclog_or_tty->print_cr("");
  2467     gclog_or_tty->print_cr("   Full Young GC Pauses:    %8d", _full_young_pause_num);
  2468     gclog_or_tty->print_cr("   Partial Young GC Pauses: %8d", _partial_young_pause_num);
  2469     gclog_or_tty->print_cr("");
  2471     gclog_or_tty->print_cr("EVACUATION PAUSES");
  2472     print_summary(_summary);
  2474     gclog_or_tty->print_cr("ABANDONED PAUSES");
  2475     print_abandoned_summary(_abandoned_summary);
  2477     gclog_or_tty->print_cr("MISC");
  2478     print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
  2479     print_summary_sd(0, "Yields", _all_yield_times_ms);
  2480     for (int i = 0; i < _aux_num; ++i) {
  2481       if (_all_aux_times_ms[i].num() > 0) {
  2482         char buffer[96];
  2483         sprintf(buffer, "Aux%d", i);
  2484         print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
  2488     size_t all_region_num = _region_num_young + _region_num_tenured;
  2489     gclog_or_tty->print_cr("   New Regions %8d, Young %8d (%6.2lf%%), "
  2490                "Tenured %8d (%6.2lf%%)",
  2491                all_region_num,
  2492                _region_num_young,
  2493                (double) _region_num_young / (double) all_region_num * 100.0,
  2494                _region_num_tenured,
  2495                (double) _region_num_tenured / (double) all_region_num * 100.0);
  2497   if (TraceGen1Time) {
  2498     if (_all_full_gc_times_ms->num() > 0) {
  2499       gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
  2500                  _all_full_gc_times_ms->num(),
  2501                  _all_full_gc_times_ms->sum() / 1000.0);
  2502       gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
  2503       gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
  2504                     _all_full_gc_times_ms->sd(),
  2505                     _all_full_gc_times_ms->maximum());
  2510 void G1CollectorPolicy::print_yg_surv_rate_info() const {
  2511 #ifndef PRODUCT
  2512   _short_lived_surv_rate_group->print_surv_rate_summary();
  2513   // add this call for any other surv rate groups
  2514 #endif // PRODUCT
  2517 bool
  2518 G1CollectorPolicy::should_add_next_region_to_young_list() {
  2519   assert(in_young_gc_mode(), "should be in young GC mode");
  2520   bool ret;
  2521   size_t young_list_length = _g1->young_list_length();
  2522   size_t young_list_max_length = _young_list_target_length;
  2523   if (G1FixedEdenSize) {
  2524     young_list_max_length -= _max_survivor_regions;
  2526   if (young_list_length < young_list_max_length) {
  2527     ret = true;
  2528     ++_region_num_young;
  2529   } else {
  2530     ret = false;
  2531     ++_region_num_tenured;
  2534   return ret;
  2537 #ifndef PRODUCT
  2538 // for debugging, bit of a hack...
  2539 static char*
  2540 region_num_to_mbs(int length) {
  2541   static char buffer[64];
  2542   double bytes = (double) (length * HeapRegion::GrainBytes);
  2543   double mbs = bytes / (double) (1024 * 1024);
  2544   sprintf(buffer, "%7.2lfMB", mbs);
  2545   return buffer;
  2547 #endif // PRODUCT
  2549 size_t G1CollectorPolicy::max_regions(int purpose) {
  2550   switch (purpose) {
  2551     case GCAllocForSurvived:
  2552       return _max_survivor_regions;
  2553     case GCAllocForTenured:
  2554       return REGIONS_UNLIMITED;
  2555     default:
  2556       ShouldNotReachHere();
  2557       return REGIONS_UNLIMITED;
  2558   };
  2561 // Calculates survivor space parameters.
  2562 void G1CollectorPolicy::calculate_survivors_policy()
  2564   if (!G1UseSurvivorSpaces) {
  2565     return;
  2567   if (G1FixedSurvivorSpaceSize == 0) {
  2568     _max_survivor_regions = _young_list_target_length / SurvivorRatio;
  2569   } else {
  2570     _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
  2573   if (G1FixedTenuringThreshold) {
  2574     _tenuring_threshold = MaxTenuringThreshold;
  2575   } else {
  2576     _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
  2577         HeapRegion::GrainWords * _max_survivor_regions);
  2581 bool
  2582 G1CollectorPolicy_BestRegionsFirst::should_do_collection_pause(size_t
  2583                                                                word_size) {
  2584   assert(_g1->regions_accounted_for(), "Region leakage!");
  2585   // Initiate a pause when we reach the steady-state "used" target.
  2586   size_t used_hard = (_g1->capacity() / 100) * G1SteadyStateUsed;
  2587   size_t used_soft =
  2588    MAX2((_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta),
  2589         used_hard/2);
  2590   size_t used = _g1->used();
  2592   double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
  2594   size_t young_list_length = _g1->young_list_length();
  2595   size_t young_list_max_length = _young_list_target_length;
  2596   if (G1FixedEdenSize) {
  2597     young_list_max_length -= _max_survivor_regions;
  2599   bool reached_target_length = young_list_length >= young_list_max_length;
  2601   if (in_young_gc_mode()) {
  2602     if (reached_target_length) {
  2603       assert( young_list_length > 0 && _g1->young_list_length() > 0,
  2604               "invariant" );
  2605       _target_pause_time_ms = max_pause_time_ms;
  2606       return true;
  2608   } else {
  2609     guarantee( false, "should not reach here" );
  2612   return false;
  2615 #ifndef PRODUCT
  2616 class HRSortIndexIsOKClosure: public HeapRegionClosure {
  2617   CollectionSetChooser* _chooser;
  2618 public:
  2619   HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
  2620     _chooser(chooser) {}
  2622   bool doHeapRegion(HeapRegion* r) {
  2623     if (!r->continuesHumongous()) {
  2624       assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
  2626     return false;
  2628 };
  2630 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
  2631   HRSortIndexIsOKClosure cl(_collectionSetChooser);
  2632   _g1->heap_region_iterate(&cl);
  2633   return true;
  2635 #endif
  2637 void
  2638 G1CollectorPolicy_BestRegionsFirst::
  2639 record_collection_pause_start(double start_time_sec, size_t start_used) {
  2640   G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
  2643 class NextNonCSElemFinder: public HeapRegionClosure {
  2644   HeapRegion* _res;
  2645 public:
  2646   NextNonCSElemFinder(): _res(NULL) {}
  2647   bool doHeapRegion(HeapRegion* r) {
  2648     if (!r->in_collection_set()) {
  2649       _res = r;
  2650       return true;
  2651     } else {
  2652       return false;
  2655   HeapRegion* res() { return _res; }
  2656 };
  2658 class KnownGarbageClosure: public HeapRegionClosure {
  2659   CollectionSetChooser* _hrSorted;
  2661 public:
  2662   KnownGarbageClosure(CollectionSetChooser* hrSorted) :
  2663     _hrSorted(hrSorted)
  2664   {}
  2666   bool doHeapRegion(HeapRegion* r) {
  2667     // We only include humongous regions in collection
  2668     // sets when concurrent mark shows that their contained object is
  2669     // unreachable.
  2671     // Do we have any marking information for this region?
  2672     if (r->is_marked()) {
  2673       // We don't include humongous regions in collection
  2674       // sets because we collect them immediately at the end of a marking
  2675       // cycle.  We also don't include young regions because we *must*
  2676       // include them in the next collection pause.
  2677       if (!r->isHumongous() && !r->is_young()) {
  2678         _hrSorted->addMarkedHeapRegion(r);
  2681     return false;
  2683 };
  2685 class ParKnownGarbageHRClosure: public HeapRegionClosure {
  2686   CollectionSetChooser* _hrSorted;
  2687   jint _marked_regions_added;
  2688   jint _chunk_size;
  2689   jint _cur_chunk_idx;
  2690   jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
  2691   int _worker;
  2692   int _invokes;
  2694   void get_new_chunk() {
  2695     _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
  2696     _cur_chunk_end = _cur_chunk_idx + _chunk_size;
  2698   void add_region(HeapRegion* r) {
  2699     if (_cur_chunk_idx == _cur_chunk_end) {
  2700       get_new_chunk();
  2702     assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
  2703     _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
  2704     _marked_regions_added++;
  2705     _cur_chunk_idx++;
  2708 public:
  2709   ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
  2710                            jint chunk_size,
  2711                            int worker) :
  2712     _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
  2713     _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
  2714     _invokes(0)
  2715   {}
  2717   bool doHeapRegion(HeapRegion* r) {
  2718     // We only include humongous regions in collection
  2719     // sets when concurrent mark shows that their contained object is
  2720     // unreachable.
  2721     _invokes++;
  2723     // Do we have any marking information for this region?
  2724     if (r->is_marked()) {
  2725       // We don't include humongous regions in collection
  2726       // sets because we collect them immediately at the end of a marking
  2727       // cycle.
  2728       // We also do not include young regions in collection sets
  2729       if (!r->isHumongous() && !r->is_young()) {
  2730         add_region(r);
  2733     return false;
  2735   jint marked_regions_added() { return _marked_regions_added; }
  2736   int invokes() { return _invokes; }
  2737 };
  2739 class ParKnownGarbageTask: public AbstractGangTask {
  2740   CollectionSetChooser* _hrSorted;
  2741   jint _chunk_size;
  2742   G1CollectedHeap* _g1;
  2743 public:
  2744   ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
  2745     AbstractGangTask("ParKnownGarbageTask"),
  2746     _hrSorted(hrSorted), _chunk_size(chunk_size),
  2747     _g1(G1CollectedHeap::heap())
  2748   {}
  2750   void work(int i) {
  2751     ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
  2752     // Back to zero for the claim value.
  2753     _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
  2754                                          HeapRegion::InitialClaimValue);
  2755     jint regions_added = parKnownGarbageCl.marked_regions_added();
  2756     _hrSorted->incNumMarkedHeapRegions(regions_added);
  2757     if (G1PrintParCleanupStats) {
  2758       gclog_or_tty->print("     Thread %d called %d times, added %d regions to list.\n",
  2759                  i, parKnownGarbageCl.invokes(), regions_added);
  2762 };
  2764 void
  2765 G1CollectorPolicy_BestRegionsFirst::
  2766 record_concurrent_mark_cleanup_end(size_t freed_bytes,
  2767                                    size_t max_live_bytes) {
  2768   double start;
  2769   if (G1PrintParCleanupStats) start = os::elapsedTime();
  2770   record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
  2772   _collectionSetChooser->clearMarkedHeapRegions();
  2773   double clear_marked_end;
  2774   if (G1PrintParCleanupStats) {
  2775     clear_marked_end = os::elapsedTime();
  2776     gclog_or_tty->print_cr("  clear marked regions + work1: %8.3f ms.",
  2777                   (clear_marked_end - start)*1000.0);
  2779   if (ParallelGCThreads > 0) {
  2780     const size_t OverpartitionFactor = 4;
  2781     const size_t MinChunkSize = 8;
  2782     const size_t ChunkSize =
  2783       MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
  2784            MinChunkSize);
  2785     _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
  2786                                                              ChunkSize);
  2787     ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
  2788                                             (int) ChunkSize);
  2789     _g1->workers()->run_task(&parKnownGarbageTask);
  2791     assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
  2792            "sanity check");
  2793   } else {
  2794     KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
  2795     _g1->heap_region_iterate(&knownGarbagecl);
  2797   double known_garbage_end;
  2798   if (G1PrintParCleanupStats) {
  2799     known_garbage_end = os::elapsedTime();
  2800     gclog_or_tty->print_cr("  compute known garbage: %8.3f ms.",
  2801                   (known_garbage_end - clear_marked_end)*1000.0);
  2803   _collectionSetChooser->sortMarkedHeapRegions();
  2804   double sort_end;
  2805   if (G1PrintParCleanupStats) {
  2806     sort_end = os::elapsedTime();
  2807     gclog_or_tty->print_cr("  sorting: %8.3f ms.",
  2808                   (sort_end - known_garbage_end)*1000.0);
  2811   record_concurrent_mark_cleanup_end_work2();
  2812   double work2_end;
  2813   if (G1PrintParCleanupStats) {
  2814     work2_end = os::elapsedTime();
  2815     gclog_or_tty->print_cr("  work2: %8.3f ms.",
  2816                   (work2_end - sort_end)*1000.0);
  2820 // Add the heap region to the collection set and return the conservative
  2821 // estimate of the number of live bytes.
  2822 void G1CollectorPolicy::
  2823 add_to_collection_set(HeapRegion* hr) {
  2824   if (G1PrintRegions) {
  2825     gclog_or_tty->print_cr("added region to cset %d:["PTR_FORMAT", "PTR_FORMAT"], "
  2826                   "top "PTR_FORMAT", young %s",
  2827                   hr->hrs_index(), hr->bottom(), hr->end(),
  2828                   hr->top(), (hr->is_young()) ? "YES" : "NO");
  2831   if (_g1->mark_in_progress())
  2832     _g1->concurrent_mark()->registerCSetRegion(hr);
  2834   assert(!hr->in_collection_set(),
  2835               "should not already be in the CSet");
  2836   hr->set_in_collection_set(true);
  2837   hr->set_next_in_collection_set(_collection_set);
  2838   _collection_set = hr;
  2839   _collection_set_size++;
  2840   _collection_set_bytes_used_before += hr->used();
  2841   _g1->register_region_with_in_cset_fast_test(hr);
  2844 void
  2845 G1CollectorPolicy_BestRegionsFirst::
  2846 choose_collection_set() {
  2847   double non_young_start_time_sec;
  2848   start_recording_regions();
  2850   guarantee(_target_pause_time_ms > -1.0,
  2851             "_target_pause_time_ms should have been set!");
  2852   assert(_collection_set == NULL, "Precondition");
  2854   double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
  2855   double predicted_pause_time_ms = base_time_ms;
  2857   double target_time_ms = _target_pause_time_ms;
  2858   double time_remaining_ms = target_time_ms - base_time_ms;
  2860   // the 10% and 50% values are arbitrary...
  2861   if (time_remaining_ms < 0.10*target_time_ms) {
  2862     time_remaining_ms = 0.50 * target_time_ms;
  2863     _within_target = false;
  2864   } else {
  2865     _within_target = true;
  2868   // We figure out the number of bytes available for future to-space.
  2869   // For new regions without marking information, we must assume the
  2870   // worst-case of complete survival.  If we have marking information for a
  2871   // region, we can bound the amount of live data.  We can add a number of
  2872   // such regions, as long as the sum of the live data bounds does not
  2873   // exceed the available evacuation space.
  2874   size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes;
  2876   size_t expansion_bytes =
  2877     _g1->expansion_regions() * HeapRegion::GrainBytes;
  2879   _collection_set_bytes_used_before = 0;
  2880   _collection_set_size = 0;
  2882   // Adjust for expansion and slop.
  2883   max_live_bytes = max_live_bytes + expansion_bytes;
  2885   assert(_g1->regions_accounted_for(), "Region leakage!");
  2887   HeapRegion* hr;
  2888   if (in_young_gc_mode()) {
  2889     double young_start_time_sec = os::elapsedTime();
  2891     if (G1PolicyVerbose > 0) {
  2892       gclog_or_tty->print_cr("Adding %d young regions to the CSet",
  2893                     _g1->young_list_length());
  2895     _young_cset_length  = 0;
  2896     _last_young_gc_full = full_young_gcs() ? true : false;
  2897     if (_last_young_gc_full)
  2898       ++_full_young_pause_num;
  2899     else
  2900       ++_partial_young_pause_num;
  2901     hr = _g1->pop_region_from_young_list();
  2902     while (hr != NULL) {
  2904       assert( hr->young_index_in_cset() == -1, "invariant" );
  2905       assert( hr->age_in_surv_rate_group() != -1, "invariant" );
  2906       hr->set_young_index_in_cset((int) _young_cset_length);
  2908       ++_young_cset_length;
  2909       double predicted_time_ms = predict_region_elapsed_time_ms(hr, true);
  2910       time_remaining_ms -= predicted_time_ms;
  2911       predicted_pause_time_ms += predicted_time_ms;
  2912       assert(!hr->in_collection_set(), "invariant");
  2913       add_to_collection_set(hr);
  2914       record_cset_region(hr, true);
  2915       max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
  2916       if (G1PolicyVerbose > 0) {
  2917         gclog_or_tty->print_cr("  Added [" PTR_FORMAT ", " PTR_FORMAT") to CS.",
  2918                       hr->bottom(), hr->end());
  2919         gclog_or_tty->print_cr("    (" SIZE_FORMAT " KB left in heap.)",
  2920                       max_live_bytes/K);
  2922       hr = _g1->pop_region_from_young_list();
  2925     record_scan_only_regions(_g1->young_list_scan_only_length());
  2927     double young_end_time_sec = os::elapsedTime();
  2928     _recorded_young_cset_choice_time_ms =
  2929       (young_end_time_sec - young_start_time_sec) * 1000.0;
  2931     non_young_start_time_sec = os::elapsedTime();
  2933     if (_young_cset_length > 0 && _last_young_gc_full) {
  2934       // don't bother adding more regions...
  2935       goto choose_collection_set_end;
  2939   if (!in_young_gc_mode() || !full_young_gcs()) {
  2940     bool should_continue = true;
  2941     NumberSeq seq;
  2942     double avg_prediction = 100000000000000000.0; // something very large
  2943     do {
  2944       hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
  2945                                                       avg_prediction);
  2946       if (hr != NULL) {
  2947         double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
  2948         time_remaining_ms -= predicted_time_ms;
  2949         predicted_pause_time_ms += predicted_time_ms;
  2950         add_to_collection_set(hr);
  2951         record_cset_region(hr, false);
  2952         max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
  2953         if (G1PolicyVerbose > 0) {
  2954           gclog_or_tty->print_cr("    (" SIZE_FORMAT " KB left in heap.)",
  2955                         max_live_bytes/K);
  2957         seq.add(predicted_time_ms);
  2958         avg_prediction = seq.avg() + seq.sd();
  2960       should_continue =
  2961         ( hr != NULL) &&
  2962         ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0
  2963           : _collection_set_size < _young_list_fixed_length );
  2964     } while (should_continue);
  2966     if (!adaptive_young_list_length() &&
  2967         _collection_set_size < _young_list_fixed_length)
  2968       _should_revert_to_full_young_gcs  = true;
  2971 choose_collection_set_end:
  2972   count_CS_bytes_used();
  2974   end_recording_regions();
  2976   double non_young_end_time_sec = os::elapsedTime();
  2977   _recorded_non_young_cset_choice_time_ms =
  2978     (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
  2981 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
  2982   G1CollectorPolicy::record_full_collection_end();
  2983   _collectionSetChooser->updateAfterFullCollection();
  2986 void G1CollectorPolicy_BestRegionsFirst::
  2987 expand_if_possible(size_t numRegions) {
  2988   size_t expansion_bytes = numRegions * HeapRegion::GrainBytes;
  2989   _g1->expand(expansion_bytes);
  2992 void G1CollectorPolicy_BestRegionsFirst::
  2993 record_collection_pause_end(bool abandoned) {
  2994   G1CollectorPolicy::record_collection_pause_end(abandoned);
  2995   assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
  2998 // Local Variables: ***
  2999 // c-indentation-style: gnu ***
  3000 // End: ***

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