1 /*
   2  * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc/g1/concurrentG1Refine.hpp"
  27 #include "gc/g1/concurrentMark.hpp"
  28 #include "gc/g1/concurrentMarkThread.inline.hpp"
  29 #include "gc/g1/g1CollectedHeap.inline.hpp"
  30 #include "gc/g1/g1CollectorPolicy.hpp"
  31 #include "gc/g1/g1ErgoVerbose.hpp"
  32 #include "gc/g1/g1GCPhaseTimes.hpp"
  33 #include "gc/g1/g1Log.hpp"
  34 #include "gc/g1/heapRegion.inline.hpp"
  35 #include "gc/g1/heapRegionRemSet.hpp"
  36 #include "gc/shared/gcPolicyCounters.hpp"
  37 #include "runtime/arguments.hpp"
  38 #include "runtime/java.hpp"
  39 #include "runtime/mutexLocker.hpp"
  40 #include "utilities/debug.hpp"
  41 
  42 // Different defaults for different number of GC threads
  43 // They were chosen by running GCOld and SPECjbb on debris with different
  44 //   numbers of GC threads and choosing them based on the results
  45 
  46 // all the same
  47 static double rs_length_diff_defaults[] = {
  48   0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
  49 };
  50 
  51 static double cost_per_card_ms_defaults[] = {
  52   0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
  53 };
  54 
  55 // all the same
  56 static double young_cards_per_entry_ratio_defaults[] = {
  57   1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
  58 };
  59 
  60 static double cost_per_entry_ms_defaults[] = {
  61   0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
  62 };
  63 
  64 static double cost_per_byte_ms_defaults[] = {
  65   0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
  66 };
  67 
  68 // these should be pretty consistent
  69 static double constant_other_time_ms_defaults[] = {
  70   5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
  71 };
  72 
  73 
  74 static double young_other_cost_per_region_ms_defaults[] = {
  75   0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
  76 };
  77 
  78 static double non_young_other_cost_per_region_ms_defaults[] = {
  79   1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
  80 };
  81 
  82 G1CollectorPolicy::G1CollectorPolicy() :
  83   _parallel_gc_threads(ParallelGCThreads),
  84 
  85   _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  86   _stop_world_start(0.0),
  87 
  88   _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  89   _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  90 
  91   _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
  92   _prev_collection_pause_end_ms(0.0),
  93   _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
  94   _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
  95   _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
  96   _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
  97   _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
  98   _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
  99   _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 100   _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
 101   _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 102   _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 103   _non_young_other_cost_per_region_ms_seq(
 104                                          new TruncatedSeq(TruncatedSeqLength)),
 105 
 106   _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
 107   _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
 108 
 109   _pause_time_target_ms((double) MaxGCPauseMillis),
 110 
 111   _recent_prev_end_times_for_all_gcs_sec(
 112                                 new TruncatedSeq(NumPrevPausesForHeuristics)),
 113 
 114   _recent_avg_pause_time_ratio(0.0),
 115 
 116   _eden_used_bytes_before_gc(0),
 117   _survivor_used_bytes_before_gc(0),
 118   _heap_used_bytes_before_gc(0),
 119   _metaspace_used_bytes_before_gc(0),
 120   _eden_capacity_bytes_before_gc(0),
 121   _heap_capacity_bytes_before_gc(0),
 122 
 123   _eden_cset_region_length(0),
 124   _survivor_cset_region_length(0),
 125   _old_cset_region_length(0),
 126 
 127   _sigma(G1ConfidencePercent / 100.0),
 128 
 129   _collection_set(NULL),
 130   _collection_set_bytes_used_before(0),
 131 
 132   // Incremental CSet attributes
 133   _inc_cset_build_state(Inactive),
 134   _inc_cset_head(NULL),
 135   _inc_cset_tail(NULL),
 136   _inc_cset_bytes_used_before(0),
 137   _inc_cset_max_finger(NULL),
 138   _inc_cset_recorded_rs_lengths(0),
 139   _inc_cset_recorded_rs_lengths_diffs(0),
 140   _inc_cset_predicted_elapsed_time_ms(0.0),
 141   _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
 142 
 143   // add here any more surv rate groups
 144   _recorded_survivor_regions(0),
 145   _recorded_survivor_head(NULL),
 146   _recorded_survivor_tail(NULL),
 147   _survivors_age_table(true),
 148 
 149   _gc_overhead_perc(0.0) {
 150 
 151   // SurvRateGroups below must be initialized after '_sigma' because they
 152   // indirectly access '_sigma' through this object passed to their constructor.
 153   _short_lived_surv_rate_group =
 154     new SurvRateGroup(this, "Short Lived", G1YoungSurvRateNumRegionsSummary);
 155   _survivor_surv_rate_group =
 156     new SurvRateGroup(this, "Survivor", G1YoungSurvRateNumRegionsSummary);
 157 
 158   // Set up the region size and associated fields. Given that the
 159   // policy is created before the heap, we have to set this up here,
 160   // so it's done as soon as possible.
 161 
 162   // It would have been natural to pass initial_heap_byte_size() and
 163   // max_heap_byte_size() to setup_heap_region_size() but those have
 164   // not been set up at this point since they should be aligned with
 165   // the region size. So, there is a circular dependency here. We base
 166   // the region size on the heap size, but the heap size should be
 167   // aligned with the region size. To get around this we use the
 168   // unaligned values for the heap.
 169   HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
 170   HeapRegionRemSet::setup_remset_size();
 171 
 172   G1ErgoVerbose::initialize();
 173   if (PrintAdaptiveSizePolicy) {
 174     // Currently, we only use a single switch for all the heuristics.
 175     G1ErgoVerbose::set_enabled(true);
 176     // Given that we don't currently have a verboseness level
 177     // parameter, we'll hardcode this to high. This can be easily
 178     // changed in the future.
 179     G1ErgoVerbose::set_level(ErgoHigh);
 180   } else {
 181     G1ErgoVerbose::set_enabled(false);
 182   }
 183 
 184   _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
 185   _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
 186 
 187   _phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
 188 
 189   int index = MIN2(_parallel_gc_threads - 1, 7);
 190 
 191   _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
 192   _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
 193   _young_cards_per_entry_ratio_seq->add(
 194                                   young_cards_per_entry_ratio_defaults[index]);
 195   _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
 196   _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
 197   _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
 198   _young_other_cost_per_region_ms_seq->add(
 199                                young_other_cost_per_region_ms_defaults[index]);
 200   _non_young_other_cost_per_region_ms_seq->add(
 201                            non_young_other_cost_per_region_ms_defaults[index]);
 202 
 203   // Below, we might need to calculate the pause time target based on
 204   // the pause interval. When we do so we are going to give G1 maximum
 205   // flexibility and allow it to do pauses when it needs to. So, we'll
 206   // arrange that the pause interval to be pause time target + 1 to
 207   // ensure that a) the pause time target is maximized with respect to
 208   // the pause interval and b) we maintain the invariant that pause
 209   // time target < pause interval. If the user does not want this
 210   // maximum flexibility, they will have to set the pause interval
 211   // explicitly.
 212 
 213   // First make sure that, if either parameter is set, its value is
 214   // reasonable.
 215   if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
 216     if (MaxGCPauseMillis < 1) {
 217       vm_exit_during_initialization("MaxGCPauseMillis should be "
 218                                     "greater than 0");
 219     }
 220   }
 221   if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 222     if (GCPauseIntervalMillis < 1) {
 223       vm_exit_during_initialization("GCPauseIntervalMillis should be "
 224                                     "greater than 0");
 225     }
 226   }
 227 
 228   // Then, if the pause time target parameter was not set, set it to
 229   // the default value.
 230   if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
 231     if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 232       // The default pause time target in G1 is 200ms
 233       FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
 234     } else {
 235       // We do not allow the pause interval to be set without the
 236       // pause time target
 237       vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
 238                                     "without setting MaxGCPauseMillis");
 239     }
 240   }
 241 
 242   // Then, if the interval parameter was not set, set it according to
 243   // the pause time target (this will also deal with the case when the
 244   // pause time target is the default value).
 245   if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 246     FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
 247   }
 248 
 249   // Finally, make sure that the two parameters are consistent.
 250   if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
 251     char buffer[256];
 252     jio_snprintf(buffer, 256,
 253                  "MaxGCPauseMillis (%u) should be less than "
 254                  "GCPauseIntervalMillis (%u)",
 255                  MaxGCPauseMillis, GCPauseIntervalMillis);
 256     vm_exit_during_initialization(buffer);
 257   }
 258 
 259   double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
 260   double time_slice  = (double) GCPauseIntervalMillis / 1000.0;
 261   _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
 262 
 263   // start conservatively (around 50ms is about right)
 264   _concurrent_mark_remark_times_ms->add(0.05);
 265   _concurrent_mark_cleanup_times_ms->add(0.20);
 266   _tenuring_threshold = MaxTenuringThreshold;
 267   // _max_survivor_regions will be calculated by
 268   // update_young_list_target_length() during initialization.
 269   _max_survivor_regions = 0;
 270 
 271   assert(GCTimeRatio > 0,
 272          "we should have set it to a default value set_g1_gc_flags() "
 273          "if a user set it to 0");
 274   _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
 275 
 276   uintx reserve_perc = G1ReservePercent;
 277   // Put an artificial ceiling on this so that it's not set to a silly value.
 278   if (reserve_perc > 50) {
 279     reserve_perc = 50;
 280     warning("G1ReservePercent is set to a value that is too large, "
 281             "it's been updated to " UINTX_FORMAT, reserve_perc);
 282   }
 283   _reserve_factor = (double) reserve_perc / 100.0;
 284   // This will be set when the heap is expanded
 285   // for the first time during initialization.
 286   _reserve_regions = 0;
 287 
 288   _collectionSetChooser = new CollectionSetChooser();
 289 }
 290 
 291 void G1CollectorPolicy::initialize_alignments() {
 292   _space_alignment = HeapRegion::GrainBytes;
 293   size_t card_table_alignment = GenRemSet::max_alignment_constraint();
 294   size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
 295   _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
 296 }
 297 
 298 void G1CollectorPolicy::initialize_flags() {
 299   if (G1HeapRegionSize != HeapRegion::GrainBytes) {
 300     FLAG_SET_ERGO(size_t, G1HeapRegionSize, HeapRegion::GrainBytes);
 301   }
 302 
 303   if (SurvivorRatio < 1) {
 304     vm_exit_during_initialization("Invalid survivor ratio specified");
 305   }
 306   CollectorPolicy::initialize_flags();
 307   _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
 308 }
 309 
 310 void G1CollectorPolicy::post_heap_initialize() {
 311   uintx max_regions = G1CollectedHeap::heap()->max_regions();
 312   size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
 313   if (max_young_size != MaxNewSize) {
 314     FLAG_SET_ERGO(size_t, MaxNewSize, max_young_size);
 315   }
 316 }
 317 
 318 G1CollectorState* G1CollectorPolicy::collector_state() { return _g1->collector_state(); }
 319 
 320 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
 321         _min_desired_young_length(0), _max_desired_young_length(0) {
 322   if (FLAG_IS_CMDLINE(NewRatio)) {
 323     if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
 324       warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
 325     } else {
 326       _sizer_kind = SizerNewRatio;
 327       _adaptive_size = false;
 328       return;
 329     }
 330   }
 331 
 332   if (NewSize > MaxNewSize) {
 333     if (FLAG_IS_CMDLINE(MaxNewSize)) {
 334       warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
 335               "A new max generation size of " SIZE_FORMAT "k will be used.",
 336               NewSize/K, MaxNewSize/K, NewSize/K);
 337     }
 338     MaxNewSize = NewSize;
 339   }
 340 
 341   if (FLAG_IS_CMDLINE(NewSize)) {
 342     _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
 343                                      1U);
 344     if (FLAG_IS_CMDLINE(MaxNewSize)) {
 345       _max_desired_young_length =
 346                              MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
 347                                   1U);
 348       _sizer_kind = SizerMaxAndNewSize;
 349       _adaptive_size = _min_desired_young_length == _max_desired_young_length;
 350     } else {
 351       _sizer_kind = SizerNewSizeOnly;
 352     }
 353   } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
 354     _max_desired_young_length =
 355                              MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
 356                                   1U);
 357     _sizer_kind = SizerMaxNewSizeOnly;
 358   }
 359 }
 360 
 361 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
 362   uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
 363   return MAX2(1U, default_value);
 364 }
 365 
 366 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
 367   uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
 368   return MAX2(1U, default_value);
 369 }
 370 
 371 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
 372   assert(number_of_heap_regions > 0, "Heap must be initialized");
 373 
 374   switch (_sizer_kind) {
 375     case SizerDefaults:
 376       *min_young_length = calculate_default_min_length(number_of_heap_regions);
 377       *max_young_length = calculate_default_max_length(number_of_heap_regions);
 378       break;
 379     case SizerNewSizeOnly:
 380       *max_young_length = calculate_default_max_length(number_of_heap_regions);
 381       *max_young_length = MAX2(*min_young_length, *max_young_length);
 382       break;
 383     case SizerMaxNewSizeOnly:
 384       *min_young_length = calculate_default_min_length(number_of_heap_regions);
 385       *min_young_length = MIN2(*min_young_length, *max_young_length);
 386       break;
 387     case SizerMaxAndNewSize:
 388       // Do nothing. Values set on the command line, don't update them at runtime.
 389       break;
 390     case SizerNewRatio:
 391       *min_young_length = number_of_heap_regions / (NewRatio + 1);
 392       *max_young_length = *min_young_length;
 393       break;
 394     default:
 395       ShouldNotReachHere();
 396   }
 397 
 398   assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
 399 }
 400 
 401 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
 402   // We need to pass the desired values because recalculation may not update these
 403   // values in some cases.
 404   uint temp = _min_desired_young_length;
 405   uint result = _max_desired_young_length;
 406   recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
 407   return result;
 408 }
 409 
 410 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
 411   recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
 412           &_max_desired_young_length);
 413 }
 414 
 415 void G1CollectorPolicy::init() {
 416   // Set aside an initial future to_space.
 417   _g1 = G1CollectedHeap::heap();
 418 
 419   assert(Heap_lock->owned_by_self(), "Locking discipline.");
 420 
 421   initialize_gc_policy_counters();
 422 
 423   if (adaptive_young_list_length()) {
 424     _young_list_fixed_length = 0;
 425   } else {
 426     _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
 427   }
 428   _free_regions_at_end_of_collection = _g1->num_free_regions();
 429   update_young_list_target_length();
 430 
 431   // We may immediately start allocating regions and placing them on the
 432   // collection set list. Initialize the per-collection set info
 433   start_incremental_cset_building();
 434 }
 435 
 436 // Create the jstat counters for the policy.
 437 void G1CollectorPolicy::initialize_gc_policy_counters() {
 438   _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
 439 }
 440 
 441 bool G1CollectorPolicy::predict_will_fit(uint young_length,
 442                                          double base_time_ms,
 443                                          uint base_free_regions,
 444                                          double target_pause_time_ms) {
 445   if (young_length >= base_free_regions) {
 446     // end condition 1: not enough space for the young regions
 447     return false;
 448   }
 449 
 450   double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
 451   size_t bytes_to_copy =
 452                (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
 453   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
 454   double young_other_time_ms = predict_young_other_time_ms(young_length);
 455   double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
 456   if (pause_time_ms > target_pause_time_ms) {
 457     // end condition 2: prediction is over the target pause time
 458     return false;
 459   }
 460 
 461   size_t free_bytes =
 462                    (base_free_regions - young_length) * HeapRegion::GrainBytes;
 463   if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
 464     // end condition 3: out-of-space (conservatively!)
 465     return false;
 466   }
 467 
 468   // success!
 469   return true;
 470 }
 471 
 472 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
 473   // re-calculate the necessary reserve
 474   double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
 475   // We use ceiling so that if reserve_regions_d is > 0.0 (but
 476   // smaller than 1.0) we'll get 1.
 477   _reserve_regions = (uint) ceil(reserve_regions_d);
 478 
 479   _young_gen_sizer->heap_size_changed(new_number_of_regions);
 480 }
 481 
 482 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
 483                                                        uint base_min_length) {
 484   uint desired_min_length = 0;
 485   if (adaptive_young_list_length()) {
 486     if (_alloc_rate_ms_seq->num() > 3) {
 487       double now_sec = os::elapsedTime();
 488       double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
 489       double alloc_rate_ms = predict_alloc_rate_ms();
 490       desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
 491     } else {
 492       // otherwise we don't have enough info to make the prediction
 493     }
 494   }
 495   desired_min_length += base_min_length;
 496   // make sure we don't go below any user-defined minimum bound
 497   return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
 498 }
 499 
 500 uint G1CollectorPolicy::calculate_young_list_desired_max_length() {
 501   // Here, we might want to also take into account any additional
 502   // constraints (i.e., user-defined minimum bound). Currently, we
 503   // effectively don't set this bound.
 504   return _young_gen_sizer->max_desired_young_length();
 505 }
 506 
 507 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
 508   if (rs_lengths == (size_t) -1) {
 509     // if it's set to the default value (-1), we should predict it;
 510     // otherwise, use the given value.
 511     rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
 512   }
 513 
 514   // Calculate the absolute and desired min bounds.
 515 
 516   // This is how many young regions we already have (currently: the survivors).
 517   uint base_min_length = recorded_survivor_regions();
 518   uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
 519   // This is the absolute minimum young length. Ensure that we
 520   // will at least have one eden region available for allocation.
 521   uint absolute_min_length = base_min_length + MAX2(_g1->young_list()->eden_length(), (uint)1);
 522   // If we shrank the young list target it should not shrink below the current size.
 523   desired_min_length = MAX2(desired_min_length, absolute_min_length);
 524   // Calculate the absolute and desired max bounds.
 525 
 526   // We will try our best not to "eat" into the reserve.
 527   uint absolute_max_length = 0;
 528   if (_free_regions_at_end_of_collection > _reserve_regions) {
 529     absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
 530   }
 531   uint desired_max_length = calculate_young_list_desired_max_length();
 532   if (desired_max_length > absolute_max_length) {
 533     desired_max_length = absolute_max_length;
 534   }
 535 
 536   uint young_list_target_length = 0;
 537   if (adaptive_young_list_length()) {
 538     if (collector_state()->gcs_are_young()) {
 539       young_list_target_length =
 540                         calculate_young_list_target_length(rs_lengths,
 541                                                            base_min_length,
 542                                                            desired_min_length,
 543                                                            desired_max_length);
 544       _rs_lengths_prediction = rs_lengths;
 545     } else {
 546       // Don't calculate anything and let the code below bound it to
 547       // the desired_min_length, i.e., do the next GC as soon as
 548       // possible to maximize how many old regions we can add to it.
 549     }
 550   } else {
 551     // The user asked for a fixed young gen so we'll fix the young gen
 552     // whether the next GC is young or mixed.
 553     young_list_target_length = _young_list_fixed_length;
 554   }
 555 
 556   // Make sure we don't go over the desired max length, nor under the
 557   // desired min length. In case they clash, desired_min_length wins
 558   // which is why that test is second.
 559   if (young_list_target_length > desired_max_length) {
 560     young_list_target_length = desired_max_length;
 561   }
 562   if (young_list_target_length < desired_min_length) {
 563     young_list_target_length = desired_min_length;
 564   }
 565 
 566   assert(young_list_target_length > recorded_survivor_regions(),
 567          "we should be able to allocate at least one eden region");
 568   assert(young_list_target_length >= absolute_min_length, "post-condition");
 569   _young_list_target_length = young_list_target_length;
 570 
 571   update_max_gc_locker_expansion();
 572 }
 573 
 574 uint
 575 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
 576                                                      uint base_min_length,
 577                                                      uint desired_min_length,
 578                                                      uint desired_max_length) {
 579   assert(adaptive_young_list_length(), "pre-condition");
 580   assert(collector_state()->gcs_are_young(), "only call this for young GCs");
 581 
 582   // In case some edge-condition makes the desired max length too small...
 583   if (desired_max_length <= desired_min_length) {
 584     return desired_min_length;
 585   }
 586 
 587   // We'll adjust min_young_length and max_young_length not to include
 588   // the already allocated young regions (i.e., so they reflect the
 589   // min and max eden regions we'll allocate). The base_min_length
 590   // will be reflected in the predictions by the
 591   // survivor_regions_evac_time prediction.
 592   assert(desired_min_length > base_min_length, "invariant");
 593   uint min_young_length = desired_min_length - base_min_length;
 594   assert(desired_max_length > base_min_length, "invariant");
 595   uint max_young_length = desired_max_length - base_min_length;
 596 
 597   double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
 598   double survivor_regions_evac_time = predict_survivor_regions_evac_time();
 599   size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
 600   size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
 601   size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
 602   double base_time_ms =
 603     predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
 604     survivor_regions_evac_time;
 605   uint available_free_regions = _free_regions_at_end_of_collection;
 606   uint base_free_regions = 0;
 607   if (available_free_regions > _reserve_regions) {
 608     base_free_regions = available_free_regions - _reserve_regions;
 609   }
 610 
 611   // Here, we will make sure that the shortest young length that
 612   // makes sense fits within the target pause time.
 613 
 614   if (predict_will_fit(min_young_length, base_time_ms,
 615                        base_free_regions, target_pause_time_ms)) {
 616     // The shortest young length will fit into the target pause time;
 617     // we'll now check whether the absolute maximum number of young
 618     // regions will fit in the target pause time. If not, we'll do
 619     // a binary search between min_young_length and max_young_length.
 620     if (predict_will_fit(max_young_length, base_time_ms,
 621                          base_free_regions, target_pause_time_ms)) {
 622       // The maximum young length will fit into the target pause time.
 623       // We are done so set min young length to the maximum length (as
 624       // the result is assumed to be returned in min_young_length).
 625       min_young_length = max_young_length;
 626     } else {
 627       // The maximum possible number of young regions will not fit within
 628       // the target pause time so we'll search for the optimal
 629       // length. The loop invariants are:
 630       //
 631       // min_young_length < max_young_length
 632       // min_young_length is known to fit into the target pause time
 633       // max_young_length is known not to fit into the target pause time
 634       //
 635       // Going into the loop we know the above hold as we've just
 636       // checked them. Every time around the loop we check whether
 637       // the middle value between min_young_length and
 638       // max_young_length fits into the target pause time. If it
 639       // does, it becomes the new min. If it doesn't, it becomes
 640       // the new max. This way we maintain the loop invariants.
 641 
 642       assert(min_young_length < max_young_length, "invariant");
 643       uint diff = (max_young_length - min_young_length) / 2;
 644       while (diff > 0) {
 645         uint young_length = min_young_length + diff;
 646         if (predict_will_fit(young_length, base_time_ms,
 647                              base_free_regions, target_pause_time_ms)) {
 648           min_young_length = young_length;
 649         } else {
 650           max_young_length = young_length;
 651         }
 652         assert(min_young_length <  max_young_length, "invariant");
 653         diff = (max_young_length - min_young_length) / 2;
 654       }
 655       // The results is min_young_length which, according to the
 656       // loop invariants, should fit within the target pause time.
 657 
 658       // These are the post-conditions of the binary search above:
 659       assert(min_young_length < max_young_length,
 660              "otherwise we should have discovered that max_young_length "
 661              "fits into the pause target and not done the binary search");
 662       assert(predict_will_fit(min_young_length, base_time_ms,
 663                               base_free_regions, target_pause_time_ms),
 664              "min_young_length, the result of the binary search, should "
 665              "fit into the pause target");
 666       assert(!predict_will_fit(min_young_length + 1, base_time_ms,
 667                                base_free_regions, target_pause_time_ms),
 668              "min_young_length, the result of the binary search, should be "
 669              "optimal, so no larger length should fit into the pause target");
 670     }
 671   } else {
 672     // Even the minimum length doesn't fit into the pause time
 673     // target, return it as the result nevertheless.
 674   }
 675   return base_min_length + min_young_length;
 676 }
 677 
 678 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
 679   double survivor_regions_evac_time = 0.0;
 680   for (HeapRegion * r = _recorded_survivor_head;
 681        r != NULL && r != _recorded_survivor_tail->get_next_young_region();
 682        r = r->get_next_young_region()) {
 683     survivor_regions_evac_time += predict_region_elapsed_time_ms(r, collector_state()->gcs_are_young());
 684   }
 685   return survivor_regions_evac_time;
 686 }
 687 
 688 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
 689   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
 690 
 691   size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
 692   if (rs_lengths > _rs_lengths_prediction) {
 693     // add 10% to avoid having to recalculate often
 694     size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
 695     update_young_list_target_length(rs_lengths_prediction);
 696   }
 697 }
 698 
 699 
 700 
 701 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
 702                                                bool is_tlab,
 703                                                bool* gc_overhead_limit_was_exceeded) {
 704   guarantee(false, "Not using this policy feature yet.");
 705   return NULL;
 706 }
 707 
 708 // This method controls how a collector handles one or more
 709 // of its generations being fully allocated.
 710 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
 711                                                        bool is_tlab) {
 712   guarantee(false, "Not using this policy feature yet.");
 713   return NULL;
 714 }
 715 
 716 
 717 #ifndef PRODUCT
 718 bool G1CollectorPolicy::verify_young_ages() {
 719   HeapRegion* head = _g1->young_list()->first_region();
 720   return
 721     verify_young_ages(head, _short_lived_surv_rate_group);
 722   // also call verify_young_ages on any additional surv rate groups
 723 }
 724 
 725 bool
 726 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
 727                                      SurvRateGroup *surv_rate_group) {
 728   guarantee( surv_rate_group != NULL, "pre-condition" );
 729 
 730   const char* name = surv_rate_group->name();
 731   bool ret = true;
 732   int prev_age = -1;
 733 
 734   for (HeapRegion* curr = head;
 735        curr != NULL;
 736        curr = curr->get_next_young_region()) {
 737     SurvRateGroup* group = curr->surv_rate_group();
 738     if (group == NULL && !curr->is_survivor()) {
 739       gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
 740       ret = false;
 741     }
 742 
 743     if (surv_rate_group == group) {
 744       int age = curr->age_in_surv_rate_group();
 745 
 746       if (age < 0) {
 747         gclog_or_tty->print_cr("## %s: encountered negative age", name);
 748         ret = false;
 749       }
 750 
 751       if (age <= prev_age) {
 752         gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
 753                                "(%d, %d)", name, age, prev_age);
 754         ret = false;
 755       }
 756       prev_age = age;
 757     }
 758   }
 759 
 760   return ret;
 761 }
 762 #endif // PRODUCT
 763 
 764 void G1CollectorPolicy::record_full_collection_start() {
 765   _full_collection_start_sec = os::elapsedTime();
 766   record_heap_size_info_at_start(true /* full */);
 767   // Release the future to-space so that it is available for compaction into.
 768   collector_state()->set_full_collection(true);
 769 }
 770 
 771 void G1CollectorPolicy::record_full_collection_end() {
 772   // Consider this like a collection pause for the purposes of allocation
 773   // since last pause.
 774   double end_sec = os::elapsedTime();
 775   double full_gc_time_sec = end_sec - _full_collection_start_sec;
 776   double full_gc_time_ms = full_gc_time_sec * 1000.0;
 777 
 778   _trace_old_gen_time_data.record_full_collection(full_gc_time_ms);
 779 
 780   update_recent_gc_times(end_sec, full_gc_time_ms);
 781 
 782   collector_state()->set_full_collection(false);
 783 
 784   // "Nuke" the heuristics that control the young/mixed GC
 785   // transitions and make sure we start with young GCs after the Full GC.
 786   collector_state()->set_gcs_are_young(true);
 787   collector_state()->set_last_young_gc(false);
 788   collector_state()->set_initiate_conc_mark_if_possible(false);
 789   collector_state()->set_during_initial_mark_pause(false);
 790   collector_state()->set_in_marking_window(false);
 791   collector_state()->set_in_marking_window_im(false);
 792 
 793   _short_lived_surv_rate_group->start_adding_regions();
 794   // also call this on any additional surv rate groups
 795 
 796   record_survivor_regions(0, NULL, NULL);
 797 
 798   _free_regions_at_end_of_collection = _g1->num_free_regions();
 799   // Reset survivors SurvRateGroup.
 800   _survivor_surv_rate_group->reset();
 801   update_young_list_target_length();
 802   _collectionSetChooser->clear();
 803 }
 804 
 805 void G1CollectorPolicy::record_stop_world_start() {
 806   _stop_world_start = os::elapsedTime();
 807 }
 808 
 809 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
 810   // We only need to do this here as the policy will only be applied
 811   // to the GC we're about to start. so, no point is calculating this
 812   // every time we calculate / recalculate the target young length.
 813   update_survivors_policy();
 814 
 815   assert(_g1->used() == _g1->recalculate_used(),
 816          "sanity, used: " SIZE_FORMAT " recalculate_used: " SIZE_FORMAT,
 817          _g1->used(), _g1->recalculate_used());
 818 
 819   double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
 820   _trace_young_gen_time_data.record_start_collection(s_w_t_ms);
 821   _stop_world_start = 0.0;
 822 
 823   record_heap_size_info_at_start(false /* full */);
 824 
 825   phase_times()->record_cur_collection_start_sec(start_time_sec);
 826   _pending_cards = _g1->pending_card_num();
 827 
 828   _collection_set_bytes_used_before = 0;
 829   _bytes_copied_during_gc = 0;
 830 
 831   collector_state()->set_last_gc_was_young(false);
 832 
 833   // do that for any other surv rate groups
 834   _short_lived_surv_rate_group->stop_adding_regions();
 835   _survivors_age_table.clear();
 836 
 837   assert( verify_young_ages(), "region age verification" );
 838 }
 839 
 840 void G1CollectorPolicy::record_concurrent_mark_init_end(double
 841                                                    mark_init_elapsed_time_ms) {
 842   collector_state()->set_during_marking(true);
 843   assert(!collector_state()->initiate_conc_mark_if_possible(), "we should have cleared it by now");
 844   collector_state()->set_during_initial_mark_pause(false);
 845   _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
 846 }
 847 
 848 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
 849   _mark_remark_start_sec = os::elapsedTime();
 850   collector_state()->set_during_marking(false);
 851 }
 852 
 853 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
 854   double end_time_sec = os::elapsedTime();
 855   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
 856   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
 857   _cur_mark_stop_world_time_ms += elapsed_time_ms;
 858   _prev_collection_pause_end_ms += elapsed_time_ms;
 859 
 860   _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, _g1->gc_tracer_cm()->gc_id());
 861 }
 862 
 863 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
 864   _mark_cleanup_start_sec = os::elapsedTime();
 865 }
 866 
 867 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
 868   collector_state()->set_last_young_gc(true);
 869   collector_state()->set_in_marking_window(false);
 870 }
 871 
 872 void G1CollectorPolicy::record_concurrent_pause() {
 873   if (_stop_world_start > 0.0) {
 874     double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
 875     _trace_young_gen_time_data.record_yield_time(yield_ms);
 876   }
 877 }
 878 
 879 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
 880   if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
 881     return false;
 882   }
 883 
 884   size_t marking_initiating_used_threshold =
 885     (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
 886   size_t cur_used_bytes = _g1->non_young_capacity_bytes();
 887   size_t alloc_byte_size = alloc_word_size * HeapWordSize;
 888 
 889   if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
 890     if (collector_state()->gcs_are_young() && !collector_state()->last_young_gc()) {
 891       ergo_verbose5(ErgoConcCycles,
 892         "request concurrent cycle initiation",
 893         ergo_format_reason("occupancy higher than threshold")
 894         ergo_format_byte("occupancy")
 895         ergo_format_byte("allocation request")
 896         ergo_format_byte_perc("threshold")
 897         ergo_format_str("source"),
 898         cur_used_bytes,
 899         alloc_byte_size,
 900         marking_initiating_used_threshold,
 901         (double) InitiatingHeapOccupancyPercent,
 902         source);
 903       return true;
 904     } else {
 905       ergo_verbose5(ErgoConcCycles,
 906         "do not request concurrent cycle initiation",
 907         ergo_format_reason("still doing mixed collections")
 908         ergo_format_byte("occupancy")
 909         ergo_format_byte("allocation request")
 910         ergo_format_byte_perc("threshold")
 911         ergo_format_str("source"),
 912         cur_used_bytes,
 913         alloc_byte_size,
 914         marking_initiating_used_threshold,
 915         (double) InitiatingHeapOccupancyPercent,
 916         source);
 917     }
 918   }
 919 
 920   return false;
 921 }
 922 
 923 // Anything below that is considered to be zero
 924 #define MIN_TIMER_GRANULARITY 0.0000001
 925 
 926 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, size_t cards_scanned) {
 927   double end_time_sec = os::elapsedTime();
 928   assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
 929          "otherwise, the subtraction below does not make sense");
 930   size_t rs_size =
 931             _cur_collection_pause_used_regions_at_start - cset_region_length();
 932   size_t cur_used_bytes = _g1->used();
 933   assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
 934   bool last_pause_included_initial_mark = false;
 935   bool update_stats = !_g1->evacuation_failed();
 936 
 937 #ifndef PRODUCT
 938   if (G1YoungSurvRateVerbose) {
 939     gclog_or_tty->cr();
 940     _short_lived_surv_rate_group->print();
 941     // do that for any other surv rate groups too
 942   }
 943 #endif // PRODUCT
 944 
 945   last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
 946   if (last_pause_included_initial_mark) {
 947     record_concurrent_mark_init_end(0.0);
 948   } else if (need_to_start_conc_mark("end of GC")) {
 949     // Note: this might have already been set, if during the last
 950     // pause we decided to start a cycle but at the beginning of
 951     // this pause we decided to postpone it. That's OK.
 952     collector_state()->set_initiate_conc_mark_if_possible(true);
 953   }
 954 
 955   _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0,
 956                           end_time_sec, _g1->gc_tracer_stw()->gc_id());
 957 
 958   if (update_stats) {
 959     _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times());
 960     // this is where we update the allocation rate of the application
 961     double app_time_ms =
 962       (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
 963     if (app_time_ms < MIN_TIMER_GRANULARITY) {
 964       // This usually happens due to the timer not having the required
 965       // granularity. Some Linuxes are the usual culprits.
 966       // We'll just set it to something (arbitrarily) small.
 967       app_time_ms = 1.0;
 968     }
 969     // We maintain the invariant that all objects allocated by mutator
 970     // threads will be allocated out of eden regions. So, we can use
 971     // the eden region number allocated since the previous GC to
 972     // calculate the application's allocate rate. The only exception
 973     // to that is humongous objects that are allocated separately. But
 974     // given that humongous object allocations do not really affect
 975     // either the pause's duration nor when the next pause will take
 976     // place we can safely ignore them here.
 977     uint regions_allocated = eden_cset_region_length();
 978     double alloc_rate_ms = (double) regions_allocated / app_time_ms;
 979     _alloc_rate_ms_seq->add(alloc_rate_ms);
 980 
 981     double interval_ms =
 982       (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
 983     update_recent_gc_times(end_time_sec, pause_time_ms);
 984     _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
 985     if (recent_avg_pause_time_ratio() < 0.0 ||
 986         (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
 987 #ifndef PRODUCT
 988       // Dump info to allow post-facto debugging
 989       gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
 990       gclog_or_tty->print_cr("-------------------------------------------");
 991       gclog_or_tty->print_cr("Recent GC Times (ms):");
 992       _recent_gc_times_ms->dump();
 993       gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
 994       _recent_prev_end_times_for_all_gcs_sec->dump();
 995       gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
 996                              _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
 997       // In debug mode, terminate the JVM if the user wants to debug at this point.
 998       assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
 999 #endif  // !PRODUCT
1000       // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1001       // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1002       if (_recent_avg_pause_time_ratio < 0.0) {
1003         _recent_avg_pause_time_ratio = 0.0;
1004       } else {
1005         assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1006         _recent_avg_pause_time_ratio = 1.0;
1007       }
1008     }
1009   }
1010 
1011   bool new_in_marking_window = collector_state()->in_marking_window();
1012   bool new_in_marking_window_im = false;
1013   if (last_pause_included_initial_mark) {
1014     new_in_marking_window = true;
1015     new_in_marking_window_im = true;
1016   }
1017 
1018   if (collector_state()->last_young_gc()) {
1019     // This is supposed to to be the "last young GC" before we start
1020     // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1021 
1022     if (!last_pause_included_initial_mark) {
1023       if (next_gc_should_be_mixed("start mixed GCs",
1024                                   "do not start mixed GCs")) {
1025         collector_state()->set_gcs_are_young(false);
1026       }
1027     } else {
1028       ergo_verbose0(ErgoMixedGCs,
1029                     "do not start mixed GCs",
1030                     ergo_format_reason("concurrent cycle is about to start"));
1031     }
1032     collector_state()->set_last_young_gc(false);
1033   }
1034 
1035   if (!collector_state()->last_gc_was_young()) {
1036     // This is a mixed GC. Here we decide whether to continue doing
1037     // mixed GCs or not.
1038 
1039     if (!next_gc_should_be_mixed("continue mixed GCs",
1040                                  "do not continue mixed GCs")) {
1041       collector_state()->set_gcs_are_young(true);
1042     }
1043   }
1044 
1045   _short_lived_surv_rate_group->start_adding_regions();
1046   // Do that for any other surv rate groups
1047 
1048   if (update_stats) {
1049     double cost_per_card_ms = 0.0;
1050     if (_pending_cards > 0) {
1051       cost_per_card_ms = phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS) / (double) _pending_cards;
1052       _cost_per_card_ms_seq->add(cost_per_card_ms);
1053     }
1054 
1055     double cost_per_entry_ms = 0.0;
1056     if (cards_scanned > 10) {
1057       cost_per_entry_ms = phase_times()->average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
1058       if (collector_state()->last_gc_was_young()) {
1059         _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1060       } else {
1061         _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1062       }
1063     }
1064 
1065     if (_max_rs_lengths > 0) {
1066       double cards_per_entry_ratio =
1067         (double) cards_scanned / (double) _max_rs_lengths;
1068       if (collector_state()->last_gc_was_young()) {
1069         _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1070       } else {
1071         _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1072       }
1073     }
1074 
1075     // This is defensive. For a while _max_rs_lengths could get
1076     // smaller than _recorded_rs_lengths which was causing
1077     // rs_length_diff to get very large and mess up the RSet length
1078     // predictions. The reason was unsafe concurrent updates to the
1079     // _inc_cset_recorded_rs_lengths field which the code below guards
1080     // against (see CR 7118202). This bug has now been fixed (see CR
1081     // 7119027). However, I'm still worried that
1082     // _inc_cset_recorded_rs_lengths might still end up somewhat
1083     // inaccurate. The concurrent refinement thread calculates an
1084     // RSet's length concurrently with other CR threads updating it
1085     // which might cause it to calculate the length incorrectly (if,
1086     // say, it's in mid-coarsening). So I'll leave in the defensive
1087     // conditional below just in case.
1088     size_t rs_length_diff = 0;
1089     if (_max_rs_lengths > _recorded_rs_lengths) {
1090       rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1091     }
1092     _rs_length_diff_seq->add((double) rs_length_diff);
1093 
1094     size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1095     size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1096     double cost_per_byte_ms = 0.0;
1097 
1098     if (copied_bytes > 0) {
1099       cost_per_byte_ms = phase_times()->average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
1100       if (collector_state()->in_marking_window()) {
1101         _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1102       } else {
1103         _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1104       }
1105     }
1106 
1107     double all_other_time_ms = pause_time_ms -
1108       (phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS) + phase_times()->average_time_ms(G1GCPhaseTimes::ScanRS) +
1109           phase_times()->average_time_ms(G1GCPhaseTimes::ObjCopy) + phase_times()->average_time_ms(G1GCPhaseTimes::Termination));
1110 
1111     double young_other_time_ms = 0.0;
1112     if (young_cset_region_length() > 0) {
1113       young_other_time_ms =
1114         phase_times()->young_cset_choice_time_ms() +
1115         phase_times()->young_free_cset_time_ms();
1116       _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1117                                           (double) young_cset_region_length());
1118     }
1119     double non_young_other_time_ms = 0.0;
1120     if (old_cset_region_length() > 0) {
1121       non_young_other_time_ms =
1122         phase_times()->non_young_cset_choice_time_ms() +
1123         phase_times()->non_young_free_cset_time_ms();
1124 
1125       _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1126                                             (double) old_cset_region_length());
1127     }
1128 
1129     double constant_other_time_ms = all_other_time_ms -
1130       (young_other_time_ms + non_young_other_time_ms);
1131     _constant_other_time_ms_seq->add(constant_other_time_ms);
1132 
1133     double survival_ratio = 0.0;
1134     if (_collection_set_bytes_used_before > 0) {
1135       survival_ratio = (double) _bytes_copied_during_gc /
1136                                    (double) _collection_set_bytes_used_before;
1137     }
1138 
1139     _pending_cards_seq->add((double) _pending_cards);
1140     _rs_lengths_seq->add((double) _max_rs_lengths);
1141   }
1142 
1143   collector_state()->set_in_marking_window(new_in_marking_window);
1144   collector_state()->set_in_marking_window_im(new_in_marking_window_im);
1145   _free_regions_at_end_of_collection = _g1->num_free_regions();
1146   update_young_list_target_length();
1147 
1148   // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1149   double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1150   adjust_concurrent_refinement(phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS),
1151                                phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS), update_rs_time_goal_ms);
1152 
1153   _collectionSetChooser->verify();
1154 }
1155 
1156 #define EXT_SIZE_FORMAT "%.1f%s"
1157 #define EXT_SIZE_PARAMS(bytes)                                  \
1158   byte_size_in_proper_unit((double)(bytes)),                    \
1159   proper_unit_for_byte_size((bytes))
1160 
1161 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1162   YoungList* young_list = _g1->young_list();
1163   _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1164   _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1165   _heap_capacity_bytes_before_gc = _g1->capacity();
1166   _heap_used_bytes_before_gc = _g1->used();
1167   _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1168 
1169   _eden_capacity_bytes_before_gc =
1170          (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1171 
1172   if (full) {
1173     _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1174   }
1175 }
1176 
1177 void G1CollectorPolicy::print_heap_transition(size_t bytes_before) {
1178   size_t bytes_after = _g1->used();
1179   size_t capacity = _g1->capacity();
1180 
1181   gclog_or_tty->print(" " SIZE_FORMAT "%s->" SIZE_FORMAT "%s(" SIZE_FORMAT "%s)",
1182       byte_size_in_proper_unit(bytes_before),
1183       proper_unit_for_byte_size(bytes_before),
1184       byte_size_in_proper_unit(bytes_after),
1185       proper_unit_for_byte_size(bytes_after),
1186       byte_size_in_proper_unit(capacity),
1187       proper_unit_for_byte_size(capacity));
1188 }
1189 
1190 void G1CollectorPolicy::print_heap_transition() {
1191   print_heap_transition(_heap_used_bytes_before_gc);
1192 }
1193 
1194 void G1CollectorPolicy::print_detailed_heap_transition(bool full) {
1195   YoungList* young_list = _g1->young_list();
1196 
1197   size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1198   size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1199   size_t heap_used_bytes_after_gc = _g1->used();
1200 
1201   size_t heap_capacity_bytes_after_gc = _g1->capacity();
1202   size_t eden_capacity_bytes_after_gc =
1203     (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1204 
1205   gclog_or_tty->print(
1206     "   [Eden: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->" EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ") "
1207     "Survivors: " EXT_SIZE_FORMAT "->" EXT_SIZE_FORMAT " "
1208     "Heap: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->"
1209     EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")]",
1210     EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1211     EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1212     EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1213     EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1214     EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1215     EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1216     EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1217     EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1218     EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1219     EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1220 
1221   if (full) {
1222     MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1223   }
1224 
1225   gclog_or_tty->cr();
1226 }
1227 
1228 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1229                                                      double update_rs_processed_buffers,
1230                                                      double goal_ms) {
1231   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1232   ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1233 
1234   if (G1UseAdaptiveConcRefinement) {
1235     const int k_gy = 3, k_gr = 6;
1236     const double inc_k = 1.1, dec_k = 0.9;
1237 
1238     int g = cg1r->green_zone();
1239     if (update_rs_time > goal_ms) {
1240       g = (int)(g * dec_k);  // Can become 0, that's OK. That would mean a mutator-only processing.
1241     } else {
1242       if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1243         g = (int)MAX2(g * inc_k, g + 1.0);
1244       }
1245     }
1246     // Change the refinement threads params
1247     cg1r->set_green_zone(g);
1248     cg1r->set_yellow_zone(g * k_gy);
1249     cg1r->set_red_zone(g * k_gr);
1250     cg1r->reinitialize_threads();
1251 
1252     int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1253     int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1254                                     cg1r->yellow_zone());
1255     // Change the barrier params
1256     dcqs.set_process_completed_threshold(processing_threshold);
1257     dcqs.set_max_completed_queue(cg1r->red_zone());
1258   }
1259 
1260   int curr_queue_size = dcqs.completed_buffers_num();
1261   if (curr_queue_size >= cg1r->yellow_zone()) {
1262     dcqs.set_completed_queue_padding(curr_queue_size);
1263   } else {
1264     dcqs.set_completed_queue_padding(0);
1265   }
1266   dcqs.notify_if_necessary();
1267 }
1268 
1269 double
1270 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1271                                                 size_t scanned_cards) {
1272   return
1273     predict_rs_update_time_ms(pending_cards) +
1274     predict_rs_scan_time_ms(scanned_cards) +
1275     predict_constant_other_time_ms();
1276 }
1277 
1278 double
1279 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1280   size_t rs_length = predict_rs_length_diff();
1281   size_t card_num;
1282   if (collector_state()->gcs_are_young()) {
1283     card_num = predict_young_card_num(rs_length);
1284   } else {
1285     card_num = predict_non_young_card_num(rs_length);
1286   }
1287   return predict_base_elapsed_time_ms(pending_cards, card_num);
1288 }
1289 
1290 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1291   size_t bytes_to_copy;
1292   if (hr->is_marked())
1293     bytes_to_copy = hr->max_live_bytes();
1294   else {
1295     assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1296     int age = hr->age_in_surv_rate_group();
1297     double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1298     bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1299   }
1300   return bytes_to_copy;
1301 }
1302 
1303 double
1304 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1305                                                   bool for_young_gc) {
1306   size_t rs_length = hr->rem_set()->occupied();
1307   size_t card_num;
1308 
1309   // Predicting the number of cards is based on which type of GC
1310   // we're predicting for.
1311   if (for_young_gc) {
1312     card_num = predict_young_card_num(rs_length);
1313   } else {
1314     card_num = predict_non_young_card_num(rs_length);
1315   }
1316   size_t bytes_to_copy = predict_bytes_to_copy(hr);
1317 
1318   double region_elapsed_time_ms =
1319     predict_rs_scan_time_ms(card_num) +
1320     predict_object_copy_time_ms(bytes_to_copy);
1321 
1322   // The prediction of the "other" time for this region is based
1323   // upon the region type and NOT the GC type.
1324   if (hr->is_young()) {
1325     region_elapsed_time_ms += predict_young_other_time_ms(1);
1326   } else {
1327     region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1328   }
1329   return region_elapsed_time_ms;
1330 }
1331 
1332 void
1333 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1334                                             uint survivor_cset_region_length) {
1335   _eden_cset_region_length     = eden_cset_region_length;
1336   _survivor_cset_region_length = survivor_cset_region_length;
1337   _old_cset_region_length      = 0;
1338 }
1339 
1340 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1341   _recorded_rs_lengths = rs_lengths;
1342 }
1343 
1344 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1345                                                double elapsed_ms) {
1346   _recent_gc_times_ms->add(elapsed_ms);
1347   _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1348   _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1349 }
1350 
1351 size_t G1CollectorPolicy::expansion_amount() {
1352   double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1353   double threshold = _gc_overhead_perc;
1354   if (recent_gc_overhead > threshold) {
1355     // We will double the existing space, or take
1356     // G1ExpandByPercentOfAvailable % of the available expansion
1357     // space, whichever is smaller, bounded below by a minimum
1358     // expansion (unless that's all that's left.)
1359     const size_t min_expand_bytes = 1*M;
1360     size_t reserved_bytes = _g1->max_capacity();
1361     size_t committed_bytes = _g1->capacity();
1362     size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1363     size_t expand_bytes;
1364     size_t expand_bytes_via_pct =
1365       uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1366     expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1367     expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1368     expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1369 
1370     ergo_verbose5(ErgoHeapSizing,
1371                   "attempt heap expansion",
1372                   ergo_format_reason("recent GC overhead higher than "
1373                                      "threshold after GC")
1374                   ergo_format_perc("recent GC overhead")
1375                   ergo_format_perc("threshold")
1376                   ergo_format_byte("uncommitted")
1377                   ergo_format_byte_perc("calculated expansion amount"),
1378                   recent_gc_overhead, threshold,
1379                   uncommitted_bytes,
1380                   expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1381 
1382     return expand_bytes;
1383   } else {
1384     return 0;
1385   }
1386 }
1387 
1388 void G1CollectorPolicy::print_tracing_info() const {
1389   _trace_young_gen_time_data.print();
1390   _trace_old_gen_time_data.print();
1391 }
1392 
1393 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1394 #ifndef PRODUCT
1395   _short_lived_surv_rate_group->print_surv_rate_summary();
1396   // add this call for any other surv rate groups
1397 #endif // PRODUCT
1398 }
1399 
1400 bool G1CollectorPolicy::is_young_list_full() {
1401   uint young_list_length = _g1->young_list()->length();
1402   uint young_list_target_length = _young_list_target_length;
1403   return young_list_length >= young_list_target_length;
1404 }
1405 
1406 bool G1CollectorPolicy::can_expand_young_list() {
1407   uint young_list_length = _g1->young_list()->length();
1408   uint young_list_max_length = _young_list_max_length;
1409   return young_list_length < young_list_max_length;
1410 }
1411 
1412 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1413   uint expansion_region_num = 0;
1414   if (GCLockerEdenExpansionPercent > 0) {
1415     double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1416     double expansion_region_num_d = perc * (double) _young_list_target_length;
1417     // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1418     // less than 1.0) we'll get 1.
1419     expansion_region_num = (uint) ceil(expansion_region_num_d);
1420   } else {
1421     assert(expansion_region_num == 0, "sanity");
1422   }
1423   _young_list_max_length = _young_list_target_length + expansion_region_num;
1424   assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1425 }
1426 
1427 // Calculates survivor space parameters.
1428 void G1CollectorPolicy::update_survivors_policy() {
1429   double max_survivor_regions_d =
1430                  (double) _young_list_target_length / (double) SurvivorRatio;
1431   // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1432   // smaller than 1.0) we'll get 1.
1433   _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1434 
1435   _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1436         HeapRegion::GrainWords * _max_survivor_regions, counters());
1437 }
1438 
1439 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
1440                                                      GCCause::Cause gc_cause) {
1441   bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1442   if (!during_cycle) {
1443     ergo_verbose1(ErgoConcCycles,
1444                   "request concurrent cycle initiation",
1445                   ergo_format_reason("requested by GC cause")
1446                   ergo_format_str("GC cause"),
1447                   GCCause::to_string(gc_cause));
1448     collector_state()->set_initiate_conc_mark_if_possible(true);
1449     return true;
1450   } else {
1451     ergo_verbose1(ErgoConcCycles,
1452                   "do not request concurrent cycle initiation",
1453                   ergo_format_reason("concurrent cycle already in progress")
1454                   ergo_format_str("GC cause"),
1455                   GCCause::to_string(gc_cause));
1456     return false;
1457   }
1458 }
1459 
1460 void
1461 G1CollectorPolicy::decide_on_conc_mark_initiation() {
1462   // We are about to decide on whether this pause will be an
1463   // initial-mark pause.
1464 
1465   // First, collector_state()->during_initial_mark_pause() should not be already set. We
1466   // will set it here if we have to. However, it should be cleared by
1467   // the end of the pause (it's only set for the duration of an
1468   // initial-mark pause).
1469   assert(!collector_state()->during_initial_mark_pause(), "pre-condition");
1470 
1471   if (collector_state()->initiate_conc_mark_if_possible()) {
1472     // We had noticed on a previous pause that the heap occupancy has
1473     // gone over the initiating threshold and we should start a
1474     // concurrent marking cycle. So we might initiate one.
1475 
1476     bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1477     if (!during_cycle) {
1478       // The concurrent marking thread is not "during a cycle", i.e.,
1479       // it has completed the last one. So we can go ahead and
1480       // initiate a new cycle.
1481 
1482       collector_state()->set_during_initial_mark_pause(true);
1483       // We do not allow mixed GCs during marking.
1484       if (!collector_state()->gcs_are_young()) {
1485         collector_state()->set_gcs_are_young(true);
1486         ergo_verbose0(ErgoMixedGCs,
1487                       "end mixed GCs",
1488                       ergo_format_reason("concurrent cycle is about to start"));
1489       }
1490 
1491       // And we can now clear initiate_conc_mark_if_possible() as
1492       // we've already acted on it.
1493       collector_state()->set_initiate_conc_mark_if_possible(false);
1494 
1495       ergo_verbose0(ErgoConcCycles,
1496                   "initiate concurrent cycle",
1497                   ergo_format_reason("concurrent cycle initiation requested"));
1498     } else {
1499       // The concurrent marking thread is still finishing up the
1500       // previous cycle. If we start one right now the two cycles
1501       // overlap. In particular, the concurrent marking thread might
1502       // be in the process of clearing the next marking bitmap (which
1503       // we will use for the next cycle if we start one). Starting a
1504       // cycle now will be bad given that parts of the marking
1505       // information might get cleared by the marking thread. And we
1506       // cannot wait for the marking thread to finish the cycle as it
1507       // periodically yields while clearing the next marking bitmap
1508       // and, if it's in a yield point, it's waiting for us to
1509       // finish. So, at this point we will not start a cycle and we'll
1510       // let the concurrent marking thread complete the last one.
1511       ergo_verbose0(ErgoConcCycles,
1512                     "do not initiate concurrent cycle",
1513                     ergo_format_reason("concurrent cycle already in progress"));
1514     }
1515   }
1516 }
1517 
1518 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1519   G1CollectedHeap* _g1h;
1520   CSetChooserParUpdater _cset_updater;
1521 
1522 public:
1523   ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1524                            uint chunk_size) :
1525     _g1h(G1CollectedHeap::heap()),
1526     _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1527 
1528   bool doHeapRegion(HeapRegion* r) {
1529     // Do we have any marking information for this region?
1530     if (r->is_marked()) {
1531       // We will skip any region that's currently used as an old GC
1532       // alloc region (we should not consider those for collection
1533       // before we fill them up).
1534       if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1535         _cset_updater.add_region(r);
1536       }
1537     }
1538     return false;
1539   }
1540 };
1541 
1542 class ParKnownGarbageTask: public AbstractGangTask {
1543   CollectionSetChooser* _hrSorted;
1544   uint _chunk_size;
1545   G1CollectedHeap* _g1;
1546   HeapRegionClaimer _hrclaimer;
1547 
1548 public:
1549   ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
1550       AbstractGangTask("ParKnownGarbageTask"),
1551       _hrSorted(hrSorted), _chunk_size(chunk_size),
1552       _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
1553 
1554   void work(uint worker_id) {
1555     ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1556     _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
1557   }
1558 };
1559 
1560 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) {
1561   assert(n_workers > 0, "Active gc workers should be greater than 0");
1562   const uint overpartition_factor = 4;
1563   const uint min_chunk_size = MAX2(n_regions / n_workers, 1U);
1564   return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size);
1565 }
1566 
1567 void
1568 G1CollectorPolicy::record_concurrent_mark_cleanup_end() {
1569   _collectionSetChooser->clear();
1570 
1571   WorkGang* workers = _g1->workers();
1572   uint n_workers = workers->active_workers();
1573 
1574   uint n_regions = _g1->num_regions();
1575   uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions);
1576   _collectionSetChooser->prepare_for_par_region_addition(n_workers, n_regions, chunk_size);
1577   ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers);
1578   workers->run_task(&par_known_garbage_task);
1579 
1580   _collectionSetChooser->sort_regions();
1581 
1582   double end_sec = os::elapsedTime();
1583   double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1584   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1585   _cur_mark_stop_world_time_ms += elapsed_time_ms;
1586   _prev_collection_pause_end_ms += elapsed_time_ms;
1587   _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, _g1->gc_tracer_cm()->gc_id());
1588 }
1589 
1590 // Add the heap region at the head of the non-incremental collection set
1591 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1592   assert(_inc_cset_build_state == Active, "Precondition");
1593   assert(hr->is_old(), "the region should be old");
1594 
1595   assert(!hr->in_collection_set(), "should not already be in the CSet");
1596   _g1->register_old_region_with_cset(hr);
1597   hr->set_next_in_collection_set(_collection_set);
1598   _collection_set = hr;
1599   _collection_set_bytes_used_before += hr->used();
1600   size_t rs_length = hr->rem_set()->occupied();
1601   _recorded_rs_lengths += rs_length;
1602   _old_cset_region_length += 1;
1603 }
1604 
1605 // Initialize the per-collection-set information
1606 void G1CollectorPolicy::start_incremental_cset_building() {
1607   assert(_inc_cset_build_state == Inactive, "Precondition");
1608 
1609   _inc_cset_head = NULL;
1610   _inc_cset_tail = NULL;
1611   _inc_cset_bytes_used_before = 0;
1612 
1613   _inc_cset_max_finger = 0;
1614   _inc_cset_recorded_rs_lengths = 0;
1615   _inc_cset_recorded_rs_lengths_diffs = 0;
1616   _inc_cset_predicted_elapsed_time_ms = 0.0;
1617   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1618   _inc_cset_build_state = Active;
1619 }
1620 
1621 void G1CollectorPolicy::finalize_incremental_cset_building() {
1622   assert(_inc_cset_build_state == Active, "Precondition");
1623   assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1624 
1625   // The two "main" fields, _inc_cset_recorded_rs_lengths and
1626   // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1627   // that adds a new region to the CSet. Further updates by the
1628   // concurrent refinement thread that samples the young RSet lengths
1629   // are accumulated in the *_diffs fields. Here we add the diffs to
1630   // the "main" fields.
1631 
1632   if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1633     _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1634   } else {
1635     // This is defensive. The diff should in theory be always positive
1636     // as RSets can only grow between GCs. However, given that we
1637     // sample their size concurrently with other threads updating them
1638     // it's possible that we might get the wrong size back, which
1639     // could make the calculations somewhat inaccurate.
1640     size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1641     if (_inc_cset_recorded_rs_lengths >= diffs) {
1642       _inc_cset_recorded_rs_lengths -= diffs;
1643     } else {
1644       _inc_cset_recorded_rs_lengths = 0;
1645     }
1646   }
1647   _inc_cset_predicted_elapsed_time_ms +=
1648                                      _inc_cset_predicted_elapsed_time_ms_diffs;
1649 
1650   _inc_cset_recorded_rs_lengths_diffs = 0;
1651   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1652 }
1653 
1654 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1655   // This routine is used when:
1656   // * adding survivor regions to the incremental cset at the end of an
1657   //   evacuation pause,
1658   // * adding the current allocation region to the incremental cset
1659   //   when it is retired, and
1660   // * updating existing policy information for a region in the
1661   //   incremental cset via young list RSet sampling.
1662   // Therefore this routine may be called at a safepoint by the
1663   // VM thread, or in-between safepoints by mutator threads (when
1664   // retiring the current allocation region) or a concurrent
1665   // refine thread (RSet sampling).
1666 
1667   double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1668   size_t used_bytes = hr->used();
1669   _inc_cset_recorded_rs_lengths += rs_length;
1670   _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1671   _inc_cset_bytes_used_before += used_bytes;
1672 
1673   // Cache the values we have added to the aggregated information
1674   // in the heap region in case we have to remove this region from
1675   // the incremental collection set, or it is updated by the
1676   // rset sampling code
1677   hr->set_recorded_rs_length(rs_length);
1678   hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1679 }
1680 
1681 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1682                                                      size_t new_rs_length) {
1683   // Update the CSet information that is dependent on the new RS length
1684   assert(hr->is_young(), "Precondition");
1685   assert(!SafepointSynchronize::is_at_safepoint(),
1686                                                "should not be at a safepoint");
1687 
1688   // We could have updated _inc_cset_recorded_rs_lengths and
1689   // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1690   // that atomically, as this code is executed by a concurrent
1691   // refinement thread, potentially concurrently with a mutator thread
1692   // allocating a new region and also updating the same fields. To
1693   // avoid the atomic operations we accumulate these updates on two
1694   // separate fields (*_diffs) and we'll just add them to the "main"
1695   // fields at the start of a GC.
1696 
1697   ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1698   ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1699   _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1700 
1701   double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1702   double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1703   double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1704   _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1705 
1706   hr->set_recorded_rs_length(new_rs_length);
1707   hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1708 }
1709 
1710 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1711   assert(hr->is_young(), "invariant");
1712   assert(hr->young_index_in_cset() > -1, "should have already been set");
1713   assert(_inc_cset_build_state == Active, "Precondition");
1714 
1715   // We need to clear and set the cached recorded/cached collection set
1716   // information in the heap region here (before the region gets added
1717   // to the collection set). An individual heap region's cached values
1718   // are calculated, aggregated with the policy collection set info,
1719   // and cached in the heap region here (initially) and (subsequently)
1720   // by the Young List sampling code.
1721 
1722   size_t rs_length = hr->rem_set()->occupied();
1723   add_to_incremental_cset_info(hr, rs_length);
1724 
1725   HeapWord* hr_end = hr->end();
1726   _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1727 
1728   assert(!hr->in_collection_set(), "invariant");
1729   _g1->register_young_region_with_cset(hr);
1730   assert(hr->next_in_collection_set() == NULL, "invariant");
1731 }
1732 
1733 // Add the region at the RHS of the incremental cset
1734 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1735   // We should only ever be appending survivors at the end of a pause
1736   assert(hr->is_survivor(), "Logic");
1737 
1738   // Do the 'common' stuff
1739   add_region_to_incremental_cset_common(hr);
1740 
1741   // Now add the region at the right hand side
1742   if (_inc_cset_tail == NULL) {
1743     assert(_inc_cset_head == NULL, "invariant");
1744     _inc_cset_head = hr;
1745   } else {
1746     _inc_cset_tail->set_next_in_collection_set(hr);
1747   }
1748   _inc_cset_tail = hr;
1749 }
1750 
1751 // Add the region to the LHS of the incremental cset
1752 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1753   // Survivors should be added to the RHS at the end of a pause
1754   assert(hr->is_eden(), "Logic");
1755 
1756   // Do the 'common' stuff
1757   add_region_to_incremental_cset_common(hr);
1758 
1759   // Add the region at the left hand side
1760   hr->set_next_in_collection_set(_inc_cset_head);
1761   if (_inc_cset_head == NULL) {
1762     assert(_inc_cset_tail == NULL, "Invariant");
1763     _inc_cset_tail = hr;
1764   }
1765   _inc_cset_head = hr;
1766 }
1767 
1768 #ifndef PRODUCT
1769 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1770   assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1771 
1772   st->print_cr("\nCollection_set:");
1773   HeapRegion* csr = list_head;
1774   while (csr != NULL) {
1775     HeapRegion* next = csr->next_in_collection_set();
1776     assert(csr->in_collection_set(), "bad CS");
1777     st->print_cr("  " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d",
1778                  HR_FORMAT_PARAMS(csr),
1779                  p2i(csr->prev_top_at_mark_start()), p2i(csr->next_top_at_mark_start()),
1780                  csr->age_in_surv_rate_group_cond());
1781     csr = next;
1782   }
1783 }
1784 #endif // !PRODUCT
1785 
1786 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) {
1787   // Returns the given amount of reclaimable bytes (that represents
1788   // the amount of reclaimable space still to be collected) as a
1789   // percentage of the current heap capacity.
1790   size_t capacity_bytes = _g1->capacity();
1791   return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1792 }
1793 
1794 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1795                                                 const char* false_action_str) {
1796   CollectionSetChooser* cset_chooser = _collectionSetChooser;
1797   if (cset_chooser->is_empty()) {
1798     ergo_verbose0(ErgoMixedGCs,
1799                   false_action_str,
1800                   ergo_format_reason("candidate old regions not available"));
1801     return false;
1802   }
1803 
1804   // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1805   size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1806   double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1807   double threshold = (double) G1HeapWastePercent;
1808   if (reclaimable_perc <= threshold) {
1809     ergo_verbose4(ErgoMixedGCs,
1810               false_action_str,
1811               ergo_format_reason("reclaimable percentage not over threshold")
1812               ergo_format_region("candidate old regions")
1813               ergo_format_byte_perc("reclaimable")
1814               ergo_format_perc("threshold"),
1815               cset_chooser->remaining_regions(),
1816               reclaimable_bytes,
1817               reclaimable_perc, threshold);
1818     return false;
1819   }
1820 
1821   ergo_verbose4(ErgoMixedGCs,
1822                 true_action_str,
1823                 ergo_format_reason("candidate old regions available")
1824                 ergo_format_region("candidate old regions")
1825                 ergo_format_byte_perc("reclaimable")
1826                 ergo_format_perc("threshold"),
1827                 cset_chooser->remaining_regions(),
1828                 reclaimable_bytes,
1829                 reclaimable_perc, threshold);
1830   return true;
1831 }
1832 
1833 uint G1CollectorPolicy::calc_min_old_cset_length() {
1834   // The min old CSet region bound is based on the maximum desired
1835   // number of mixed GCs after a cycle. I.e., even if some old regions
1836   // look expensive, we should add them to the CSet anyway to make
1837   // sure we go through the available old regions in no more than the
1838   // maximum desired number of mixed GCs.
1839   //
1840   // The calculation is based on the number of marked regions we added
1841   // to the CSet chooser in the first place, not how many remain, so
1842   // that the result is the same during all mixed GCs that follow a cycle.
1843 
1844   const size_t region_num = (size_t) _collectionSetChooser->length();
1845   const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
1846   size_t result = region_num / gc_num;
1847   // emulate ceiling
1848   if (result * gc_num < region_num) {
1849     result += 1;
1850   }
1851   return (uint) result;
1852 }
1853 
1854 uint G1CollectorPolicy::calc_max_old_cset_length() {
1855   // The max old CSet region bound is based on the threshold expressed
1856   // as a percentage of the heap size. I.e., it should bound the
1857   // number of old regions added to the CSet irrespective of how many
1858   // of them are available.
1859 
1860   G1CollectedHeap* g1h = G1CollectedHeap::heap();
1861   const size_t region_num = g1h->num_regions();
1862   const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
1863   size_t result = region_num * perc / 100;
1864   // emulate ceiling
1865   if (100 * result < region_num * perc) {
1866     result += 1;
1867   }
1868   return (uint) result;
1869 }
1870 
1871 
1872 double G1CollectorPolicy::finalize_young_cset_part(double target_pause_time_ms) {
1873   double young_start_time_sec = os::elapsedTime();
1874 
1875   YoungList* young_list = _g1->young_list();
1876   finalize_incremental_cset_building();
1877 
1878   guarantee(target_pause_time_ms > 0.0,
1879             "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms);
1880   guarantee(_collection_set == NULL, "Precondition");
1881 
1882   double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
1883   double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
1884 
1885   ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
1886                 "start choosing CSet",
1887                 ergo_format_size("_pending_cards")
1888                 ergo_format_ms("predicted base time")
1889                 ergo_format_ms("remaining time")
1890                 ergo_format_ms("target pause time"),
1891                 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
1892 
1893   collector_state()->set_last_gc_was_young(collector_state()->gcs_are_young());
1894 
1895   if (collector_state()->last_gc_was_young()) {
1896     _trace_young_gen_time_data.increment_young_collection_count();
1897   } else {
1898     _trace_young_gen_time_data.increment_mixed_collection_count();
1899   }
1900 
1901   // The young list is laid with the survivor regions from the previous
1902   // pause are appended to the RHS of the young list, i.e.
1903   //   [Newly Young Regions ++ Survivors from last pause].
1904 
1905   uint survivor_region_length = young_list->survivor_length();
1906   uint eden_region_length = young_list->eden_length();
1907   init_cset_region_lengths(eden_region_length, survivor_region_length);
1908 
1909   HeapRegion* hr = young_list->first_survivor_region();
1910   while (hr != NULL) {
1911     assert(hr->is_survivor(), "badly formed young list");
1912     // There is a convention that all the young regions in the CSet
1913     // are tagged as "eden", so we do this for the survivors here. We
1914     // use the special set_eden_pre_gc() as it doesn't check that the
1915     // region is free (which is not the case here).
1916     hr->set_eden_pre_gc();
1917     hr = hr->get_next_young_region();
1918   }
1919 
1920   // Clear the fields that point to the survivor list - they are all young now.
1921   young_list->clear_survivors();
1922 
1923   _collection_set = _inc_cset_head;
1924   _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
1925   time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
1926 
1927   ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
1928                 "add young regions to CSet",
1929                 ergo_format_region("eden")
1930                 ergo_format_region("survivors")
1931                 ergo_format_ms("predicted young region time")
1932                 ergo_format_ms("target pause time"),
1933                 eden_region_length, survivor_region_length,
1934                 _inc_cset_predicted_elapsed_time_ms,
1935                 target_pause_time_ms);
1936 
1937   // The number of recorded young regions is the incremental
1938   // collection set's current size
1939   set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
1940 
1941   double young_end_time_sec = os::elapsedTime();
1942   phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
1943 
1944   return time_remaining_ms;
1945 }
1946 
1947 void G1CollectorPolicy::finalize_old_cset_part(double time_remaining_ms) {
1948   double non_young_start_time_sec = os::elapsedTime();
1949   double predicted_old_time_ms = 0.0;
1950 
1951 
1952   if (!collector_state()->gcs_are_young()) {
1953     CollectionSetChooser* cset_chooser = _collectionSetChooser;
1954     cset_chooser->verify();
1955     const uint min_old_cset_length = calc_min_old_cset_length();
1956     const uint max_old_cset_length = calc_max_old_cset_length();
1957 
1958     uint expensive_region_num = 0;
1959     bool check_time_remaining = adaptive_young_list_length();
1960 
1961     HeapRegion* hr = cset_chooser->peek();
1962     while (hr != NULL) {
1963       if (old_cset_region_length() >= max_old_cset_length) {
1964         // Added maximum number of old regions to the CSet.
1965         ergo_verbose2(ErgoCSetConstruction,
1966                       "finish adding old regions to CSet",
1967                       ergo_format_reason("old CSet region num reached max")
1968                       ergo_format_region("old")
1969                       ergo_format_region("max"),
1970                       old_cset_region_length(), max_old_cset_length);
1971         break;
1972       }
1973 
1974 
1975       // Stop adding regions if the remaining reclaimable space is
1976       // not above G1HeapWastePercent.
1977       size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1978       double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1979       double threshold = (double) G1HeapWastePercent;
1980       if (reclaimable_perc <= threshold) {
1981         // We've added enough old regions that the amount of uncollected
1982         // reclaimable space is at or below the waste threshold. Stop
1983         // adding old regions to the CSet.
1984         ergo_verbose5(ErgoCSetConstruction,
1985                       "finish adding old regions to CSet",
1986                       ergo_format_reason("reclaimable percentage not over threshold")
1987                       ergo_format_region("old")
1988                       ergo_format_region("max")
1989                       ergo_format_byte_perc("reclaimable")
1990                       ergo_format_perc("threshold"),
1991                       old_cset_region_length(),
1992                       max_old_cset_length,
1993                       reclaimable_bytes,
1994                       reclaimable_perc, threshold);
1995         break;
1996       }
1997 
1998       double predicted_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1999       if (check_time_remaining) {
2000         if (predicted_time_ms > time_remaining_ms) {
2001           // Too expensive for the current CSet.
2002 
2003           if (old_cset_region_length() >= min_old_cset_length) {
2004             // We have added the minimum number of old regions to the CSet,
2005             // we are done with this CSet.
2006             ergo_verbose4(ErgoCSetConstruction,
2007                           "finish adding old regions to CSet",
2008                           ergo_format_reason("predicted time is too high")
2009                           ergo_format_ms("predicted time")
2010                           ergo_format_ms("remaining time")
2011                           ergo_format_region("old")
2012                           ergo_format_region("min"),
2013                           predicted_time_ms, time_remaining_ms,
2014                           old_cset_region_length(), min_old_cset_length);
2015             break;
2016           }
2017 
2018           // We'll add it anyway given that we haven't reached the
2019           // minimum number of old regions.
2020           expensive_region_num += 1;
2021         }
2022       } else {
2023         if (old_cset_region_length() >= min_old_cset_length) {
2024           // In the non-auto-tuning case, we'll finish adding regions
2025           // to the CSet if we reach the minimum.
2026           ergo_verbose2(ErgoCSetConstruction,
2027                         "finish adding old regions to CSet",
2028                         ergo_format_reason("old CSet region num reached min")
2029                         ergo_format_region("old")
2030                         ergo_format_region("min"),
2031                         old_cset_region_length(), min_old_cset_length);
2032           break;
2033         }
2034       }
2035 
2036       // We will add this region to the CSet.
2037       time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2038       predicted_old_time_ms += predicted_time_ms;
2039       cset_chooser->pop(); // already have region via peek()
2040       _g1->old_set_remove(hr);
2041       add_old_region_to_cset(hr);
2042 
2043       hr = cset_chooser->peek();
2044     }
2045     if (hr == NULL) {
2046       ergo_verbose0(ErgoCSetConstruction,
2047                     "finish adding old regions to CSet",
2048                     ergo_format_reason("candidate old regions not available"));
2049     }
2050 
2051     if (expensive_region_num > 0) {
2052       // We print the information once here at the end, predicated on
2053       // whether we added any apparently expensive regions or not, to
2054       // avoid generating output per region.
2055       ergo_verbose4(ErgoCSetConstruction,
2056                     "added expensive regions to CSet",
2057                     ergo_format_reason("old CSet region num not reached min")
2058                     ergo_format_region("old")
2059                     ergo_format_region("expensive")
2060                     ergo_format_region("min")
2061                     ergo_format_ms("remaining time"),
2062                     old_cset_region_length(),
2063                     expensive_region_num,
2064                     min_old_cset_length,
2065                     time_remaining_ms);
2066     }
2067 
2068     cset_chooser->verify();
2069   }
2070 
2071   stop_incremental_cset_building();
2072 
2073   ergo_verbose3(ErgoCSetConstruction,
2074                 "finish choosing CSet",
2075                 ergo_format_region("old")
2076                 ergo_format_ms("predicted old region time")
2077                 ergo_format_ms("time remaining"),
2078                 old_cset_region_length(),
2079                 predicted_old_time_ms, time_remaining_ms);
2080 
2081   double non_young_end_time_sec = os::elapsedTime();
2082   phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2083 }
2084 
2085 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) {
2086   if(TraceYoungGenTime) {
2087     _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2088   }
2089 }
2090 
2091 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) {
2092   if(TraceYoungGenTime) {
2093     _all_yield_times_ms.add(yield_time_ms);
2094   }
2095 }
2096 
2097 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2098   if(TraceYoungGenTime) {
2099     _total.add(pause_time_ms);
2100     _other.add(pause_time_ms - phase_times->accounted_time_ms());
2101     _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2102     _parallel.add(phase_times->cur_collection_par_time_ms());
2103     _ext_root_scan.add(phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan));
2104     _satb_filtering.add(phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering));
2105     _update_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS));
2106     _scan_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::ScanRS));
2107     _obj_copy.add(phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy));
2108     _termination.add(phase_times->average_time_ms(G1GCPhaseTimes::Termination));
2109 
2110     double parallel_known_time = phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan) +
2111       phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering) +
2112       phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS) +
2113       phase_times->average_time_ms(G1GCPhaseTimes::ScanRS) +
2114       phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy) +
2115       phase_times->average_time_ms(G1GCPhaseTimes::Termination);
2116 
2117     double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2118     _parallel_other.add(parallel_other_time);
2119     _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2120   }
2121 }
2122 
2123 void TraceYoungGenTimeData::increment_young_collection_count() {
2124   if(TraceYoungGenTime) {
2125     ++_young_pause_num;
2126   }
2127 }
2128 
2129 void TraceYoungGenTimeData::increment_mixed_collection_count() {
2130   if(TraceYoungGenTime) {
2131     ++_mixed_pause_num;
2132   }
2133 }
2134 
2135 void TraceYoungGenTimeData::print_summary(const char* str,
2136                                           const NumberSeq* seq) const {
2137   double sum = seq->sum();
2138   gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2139                 str, sum / 1000.0, seq->avg());
2140 }
2141 
2142 void TraceYoungGenTimeData::print_summary_sd(const char* str,
2143                                              const NumberSeq* seq) const {
2144   print_summary(str, seq);
2145   gclog_or_tty->print_cr("%45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2146                 "(num", seq->num(), seq->sd(), seq->maximum());
2147 }
2148 
2149 void TraceYoungGenTimeData::print() const {
2150   if (!TraceYoungGenTime) {
2151     return;
2152   }
2153 
2154   gclog_or_tty->print_cr("ALL PAUSES");
2155   print_summary_sd("   Total", &_total);
2156   gclog_or_tty->cr();
2157   gclog_or_tty->cr();
2158   gclog_or_tty->print_cr("   Young GC Pauses: %8d", _young_pause_num);
2159   gclog_or_tty->print_cr("   Mixed GC Pauses: %8d", _mixed_pause_num);
2160   gclog_or_tty->cr();
2161 
2162   gclog_or_tty->print_cr("EVACUATION PAUSES");
2163 
2164   if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2165     gclog_or_tty->print_cr("none");
2166   } else {
2167     print_summary_sd("   Evacuation Pauses", &_total);
2168     print_summary("      Root Region Scan Wait", &_root_region_scan_wait);
2169     print_summary("      Parallel Time", &_parallel);
2170     print_summary("         Ext Root Scanning", &_ext_root_scan);
2171     print_summary("         SATB Filtering", &_satb_filtering);
2172     print_summary("         Update RS", &_update_rs);
2173     print_summary("         Scan RS", &_scan_rs);
2174     print_summary("         Object Copy", &_obj_copy);
2175     print_summary("         Termination", &_termination);
2176     print_summary("         Parallel Other", &_parallel_other);
2177     print_summary("      Clear CT", &_clear_ct);
2178     print_summary("      Other", &_other);
2179   }
2180   gclog_or_tty->cr();
2181 
2182   gclog_or_tty->print_cr("MISC");
2183   print_summary_sd("   Stop World", &_all_stop_world_times_ms);
2184   print_summary_sd("   Yields", &_all_yield_times_ms);
2185 }
2186 
2187 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) {
2188   if (TraceOldGenTime) {
2189     _all_full_gc_times.add(full_gc_time_ms);
2190   }
2191 }
2192 
2193 void TraceOldGenTimeData::print() const {
2194   if (!TraceOldGenTime) {
2195     return;
2196   }
2197 
2198   if (_all_full_gc_times.num() > 0) {
2199     gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2200       _all_full_gc_times.num(),
2201       _all_full_gc_times.sum() / 1000.0);
2202     gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2203     gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
2204       _all_full_gc_times.sd(),
2205       _all_full_gc_times.maximum());
2206   }
2207 }