rev 9416 : dihop-changes
rev 9418 : imported patch erik-jmasa-review
rev 9419 : imported patch fix-evac-failure-needs-stats

   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   _predictor(G1ConfidencePercent / 100.0),
  84   _parallel_gc_threads(ParallelGCThreads),
  85 
  86   _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  87   _stop_world_start(0.0),
  88 
  89   _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  90   _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  91 
  92   _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
  93   _prev_collection_pause_end_ms(0.0),
  94   _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
  95   _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
  96   _cost_scan_hcc_seq(new TruncatedSeq(TruncatedSeqLength)),
  97   _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
  98   _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
  99   _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 100   _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 101   _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 102   _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
 103   _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 104   _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 105   _non_young_other_cost_per_region_ms_seq(
 106                                          new TruncatedSeq(TruncatedSeqLength)),
 107 
 108   _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
 109   _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
 110 
 111   _pause_time_target_ms((double) MaxGCPauseMillis),
 112 
 113   _recent_prev_end_times_for_all_gcs_sec(
 114                                 new TruncatedSeq(NumPrevPausesForHeuristics)),
 115 
 116   _recent_avg_pause_time_ratio(0.0),
 117   _rs_lengths_prediction(0),
 118   _max_survivor_regions(0),
 119 
 120   _eden_used_bytes_before_gc(0),
 121   _survivor_used_bytes_before_gc(0),
 122   _heap_used_bytes_before_gc(0),
 123   _metaspace_used_bytes_before_gc(0),
 124   _eden_capacity_bytes_before_gc(0),
 125   _heap_capacity_bytes_before_gc(0),
 126 
 127   _eden_cset_region_length(0),
 128   _survivor_cset_region_length(0),
 129   _old_cset_region_length(0),
 130 
 131   _collection_set(NULL),
 132   _collection_set_bytes_used_before(0),
 133 
 134   // Incremental CSet attributes
 135   _inc_cset_build_state(Inactive),
 136   _inc_cset_head(NULL),
 137   _inc_cset_tail(NULL),
 138   _inc_cset_bytes_used_before(0),
 139   _inc_cset_max_finger(NULL),
 140   _inc_cset_recorded_rs_lengths(0),
 141   _inc_cset_recorded_rs_lengths_diffs(0),
 142   _inc_cset_predicted_elapsed_time_ms(0.0),
 143   _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
 144 
 145   // add here any more surv rate groups
 146   _recorded_survivor_regions(0),
 147   _recorded_survivor_head(NULL),
 148   _recorded_survivor_tail(NULL),
 149   _survivors_age_table(true),
 150 
 151   _gc_overhead_perc(0.0) {




 152 
 153   // SurvRateGroups below must be initialized after the predictor because they
 154   // indirectly use it through this object passed to their constructor.
 155   _short_lived_surv_rate_group =
 156     new SurvRateGroup(&_predictor, "Short Lived", G1YoungSurvRateNumRegionsSummary);
 157   _survivor_surv_rate_group =
 158     new SurvRateGroup(&_predictor, "Survivor", G1YoungSurvRateNumRegionsSummary);
 159 
 160   // Set up the region size and associated fields. Given that the
 161   // policy is created before the heap, we have to set this up here,
 162   // so it's done as soon as possible.
 163 
 164   // It would have been natural to pass initial_heap_byte_size() and
 165   // max_heap_byte_size() to setup_heap_region_size() but those have
 166   // not been set up at this point since they should be aligned with
 167   // the region size. So, there is a circular dependency here. We base
 168   // the region size on the heap size, but the heap size should be
 169   // aligned with the region size. To get around this we use the
 170   // unaligned values for the heap.
 171   HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
 172   HeapRegionRemSet::setup_remset_size();
 173 
 174   G1ErgoVerbose::initialize();
 175   if (PrintAdaptiveSizePolicy) {
 176     // Currently, we only use a single switch for all the heuristics.
 177     G1ErgoVerbose::set_enabled(true);
 178     // Given that we don't currently have a verboseness level
 179     // parameter, we'll hardcode this to high. This can be easily
 180     // changed in the future.
 181     G1ErgoVerbose::set_level(ErgoHigh);
 182   } else {
 183     G1ErgoVerbose::set_enabled(false);
 184   }
 185 
 186   _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
 187   _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
 188 
 189   _phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
 190 
 191   int index = MIN2(_parallel_gc_threads - 1, 7);
 192 
 193   _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
 194   _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
 195   _cost_scan_hcc_seq->add(0.0);
 196   _young_cards_per_entry_ratio_seq->add(
 197                                   young_cards_per_entry_ratio_defaults[index]);
 198   _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
 199   _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
 200   _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
 201   _young_other_cost_per_region_ms_seq->add(
 202                                young_other_cost_per_region_ms_defaults[index]);
 203   _non_young_other_cost_per_region_ms_seq->add(
 204                            non_young_other_cost_per_region_ms_defaults[index]);
 205 
 206   // Below, we might need to calculate the pause time target based on
 207   // the pause interval. When we do so we are going to give G1 maximum
 208   // flexibility and allow it to do pauses when it needs to. So, we'll
 209   // arrange that the pause interval to be pause time target + 1 to
 210   // ensure that a) the pause time target is maximized with respect to
 211   // the pause interval and b) we maintain the invariant that pause
 212   // time target < pause interval. If the user does not want this
 213   // maximum flexibility, they will have to set the pause interval
 214   // explicitly.
 215 
 216   // First make sure that, if either parameter is set, its value is
 217   // reasonable.
 218   if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
 219     if (MaxGCPauseMillis < 1) {
 220       vm_exit_during_initialization("MaxGCPauseMillis should be "
 221                                     "greater than 0");
 222     }
 223   }
 224   if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 225     if (GCPauseIntervalMillis < 1) {
 226       vm_exit_during_initialization("GCPauseIntervalMillis should be "
 227                                     "greater than 0");
 228     }
 229   }
 230 
 231   // Then, if the pause time target parameter was not set, set it to
 232   // the default value.
 233   if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
 234     if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 235       // The default pause time target in G1 is 200ms
 236       FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
 237     } else {
 238       // We do not allow the pause interval to be set without the
 239       // pause time target
 240       vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
 241                                     "without setting MaxGCPauseMillis");
 242     }
 243   }
 244 
 245   // Then, if the interval parameter was not set, set it according to
 246   // the pause time target (this will also deal with the case when the
 247   // pause time target is the default value).
 248   if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 249     FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
 250   }
 251 
 252   // Finally, make sure that the two parameters are consistent.
 253   if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
 254     char buffer[256];
 255     jio_snprintf(buffer, 256,
 256                  "MaxGCPauseMillis (%u) should be less than "
 257                  "GCPauseIntervalMillis (%u)",
 258                  MaxGCPauseMillis, GCPauseIntervalMillis);
 259     vm_exit_during_initialization(buffer);
 260   }
 261 
 262   double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
 263   double time_slice  = (double) GCPauseIntervalMillis / 1000.0;
 264   _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
 265 
 266   // start conservatively (around 50ms is about right)
 267   _concurrent_mark_remark_times_ms->add(0.05);
 268   _concurrent_mark_cleanup_times_ms->add(0.20);
 269   _tenuring_threshold = MaxTenuringThreshold;
 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 double G1CollectorPolicy::get_new_prediction(TruncatedSeq const* seq) const {
 292   return _predictor.get_new_prediction(seq);
 293 }
 294 
 295 void G1CollectorPolicy::initialize_alignments() {
 296   _space_alignment = HeapRegion::GrainBytes;
 297   size_t card_table_alignment = CardTableRS::ct_max_alignment_constraint();
 298   size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
 299   _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
 300 }
 301 
 302 void G1CollectorPolicy::initialize_flags() {
 303   if (G1HeapRegionSize != HeapRegion::GrainBytes) {
 304     FLAG_SET_ERGO(size_t, G1HeapRegionSize, HeapRegion::GrainBytes);
 305   }
 306 
 307   if (SurvivorRatio < 1) {
 308     vm_exit_during_initialization("Invalid survivor ratio specified");
 309   }
 310   CollectorPolicy::initialize_flags();
 311   _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
 312 }
 313 
 314 void G1CollectorPolicy::post_heap_initialize() {
 315   uintx max_regions = G1CollectedHeap::heap()->max_regions();
 316   size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
 317   if (max_young_size != MaxNewSize) {
 318     FLAG_SET_ERGO(size_t, MaxNewSize, max_young_size);
 319   }


 320 }
 321 
 322 G1CollectorState* G1CollectorPolicy::collector_state() const { return _g1->collector_state(); }
 323 
 324 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
 325         _min_desired_young_length(0), _max_desired_young_length(0) {
 326   if (FLAG_IS_CMDLINE(NewRatio)) {
 327     if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
 328       warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
 329     } else {
 330       _sizer_kind = SizerNewRatio;
 331       _adaptive_size = false;
 332       return;
 333     }
 334   }
 335 
 336   if (NewSize > MaxNewSize) {
 337     if (FLAG_IS_CMDLINE(MaxNewSize)) {
 338       warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
 339               "A new max generation size of " SIZE_FORMAT "k will be used.",
 340               NewSize/K, MaxNewSize/K, NewSize/K);
 341     }
 342     MaxNewSize = NewSize;
 343   }
 344 
 345   if (FLAG_IS_CMDLINE(NewSize)) {
 346     _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
 347                                      1U);
 348     if (FLAG_IS_CMDLINE(MaxNewSize)) {
 349       _max_desired_young_length =
 350                              MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
 351                                   1U);
 352       _sizer_kind = SizerMaxAndNewSize;
 353       _adaptive_size = _min_desired_young_length == _max_desired_young_length;
 354     } else {
 355       _sizer_kind = SizerNewSizeOnly;
 356     }
 357   } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
 358     _max_desired_young_length =
 359                              MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
 360                                   1U);
 361     _sizer_kind = SizerMaxNewSizeOnly;
 362   }
 363 }
 364 
 365 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
 366   uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
 367   return MAX2(1U, default_value);
 368 }
 369 
 370 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
 371   uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
 372   return MAX2(1U, default_value);
 373 }
 374 
 375 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
 376   assert(number_of_heap_regions > 0, "Heap must be initialized");
 377 
 378   switch (_sizer_kind) {
 379     case SizerDefaults:
 380       *min_young_length = calculate_default_min_length(number_of_heap_regions);
 381       *max_young_length = calculate_default_max_length(number_of_heap_regions);
 382       break;
 383     case SizerNewSizeOnly:
 384       *max_young_length = calculate_default_max_length(number_of_heap_regions);
 385       *max_young_length = MAX2(*min_young_length, *max_young_length);
 386       break;
 387     case SizerMaxNewSizeOnly:
 388       *min_young_length = calculate_default_min_length(number_of_heap_regions);
 389       *min_young_length = MIN2(*min_young_length, *max_young_length);
 390       break;
 391     case SizerMaxAndNewSize:
 392       // Do nothing. Values set on the command line, don't update them at runtime.
 393       break;
 394     case SizerNewRatio:
 395       *min_young_length = number_of_heap_regions / (NewRatio + 1);
 396       *max_young_length = *min_young_length;
 397       break;
 398     default:
 399       ShouldNotReachHere();
 400   }
 401 
 402   assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
 403 }
 404 
 405 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
 406   // We need to pass the desired values because recalculation may not update these
 407   // values in some cases.
 408   uint temp = _min_desired_young_length;
 409   uint result = _max_desired_young_length;
 410   recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
 411   return result;
 412 }
 413 
 414 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
 415   recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
 416           &_max_desired_young_length);
 417 }
 418 
 419 void G1CollectorPolicy::init() {
 420   // Set aside an initial future to_space.
 421   _g1 = G1CollectedHeap::heap();
 422 
 423   assert(Heap_lock->owned_by_self(), "Locking discipline.");
 424 
 425   initialize_gc_policy_counters();
 426 
 427   if (adaptive_young_list_length()) {
 428     _young_list_fixed_length = 0;
 429   } else {
 430     _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
 431   }
 432   _free_regions_at_end_of_collection = _g1->num_free_regions();
 433 
 434   update_young_list_max_and_target_length();
 435   // We may immediately start allocating regions and placing them on the
 436   // collection set list. Initialize the per-collection set info
 437   start_incremental_cset_building();
 438 }
 439 
 440 void G1CollectorPolicy::note_gc_start(uint num_active_workers) {
 441   phase_times()->note_gc_start(num_active_workers);
 442 }
 443 
 444 // Create the jstat counters for the policy.
 445 void G1CollectorPolicy::initialize_gc_policy_counters() {
 446   _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
 447 }
 448 
 449 bool G1CollectorPolicy::predict_will_fit(uint young_length,
 450                                          double base_time_ms,
 451                                          uint base_free_regions,
 452                                          double target_pause_time_ms) const {
 453   if (young_length >= base_free_regions) {
 454     // end condition 1: not enough space for the young regions
 455     return false;
 456   }
 457 
 458   double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
 459   size_t bytes_to_copy =
 460                (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
 461   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
 462   double young_other_time_ms = predict_young_other_time_ms(young_length);
 463   double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
 464   if (pause_time_ms > target_pause_time_ms) {
 465     // end condition 2: prediction is over the target pause time
 466     return false;
 467   }
 468 
 469   size_t free_bytes = (base_free_regions - young_length) * HeapRegion::GrainBytes;
 470 
 471   // When copying, we will likely need more bytes free than is live in the region.
 472   // Add some safety margin to factor in the confidence of our guess, and the
 473   // natural expected waste.
 474   // (100.0 / G1ConfidencePercent) is a scale factor that expresses the uncertainty
 475   // of the calculation: the lower the confidence, the more headroom.
 476   // (100 + TargetPLABWastePct) represents the increase in expected bytes during
 477   // copying due to anticipated waste in the PLABs.
 478   double safety_factor = (100.0 / G1ConfidencePercent) * (100 + TargetPLABWastePct) / 100.0;
 479   size_t expected_bytes_to_copy = safety_factor * bytes_to_copy;
 480 
 481   if (expected_bytes_to_copy > free_bytes) {
 482     // end condition 3: out-of-space
 483     return false;
 484   }
 485 
 486   // success!
 487   return true;
 488 }
 489 
 490 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
 491   // re-calculate the necessary reserve
 492   double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
 493   // We use ceiling so that if reserve_regions_d is > 0.0 (but
 494   // smaller than 1.0) we'll get 1.
 495   _reserve_regions = (uint) ceil(reserve_regions_d);
 496 
 497   _young_gen_sizer->heap_size_changed(new_number_of_regions);
 498 }
 499 
 500 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
 501                                                        uint base_min_length) const {
 502   uint desired_min_length = 0;
 503   if (adaptive_young_list_length()) {
 504     if (_alloc_rate_ms_seq->num() > 3) {
 505       double now_sec = os::elapsedTime();
 506       double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
 507       double alloc_rate_ms = predict_alloc_rate_ms();
 508       desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
 509     } else {
 510       // otherwise we don't have enough info to make the prediction
 511     }
 512   }
 513   desired_min_length += base_min_length;
 514   // make sure we don't go below any user-defined minimum bound
 515   return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
 516 }
 517 
 518 uint G1CollectorPolicy::calculate_young_list_desired_max_length() const {
 519   // Here, we might want to also take into account any additional
 520   // constraints (i.e., user-defined minimum bound). Currently, we
 521   // effectively don't set this bound.
 522   return _young_gen_sizer->max_desired_young_length();
 523 }
 524 
 525 void G1CollectorPolicy::update_young_list_max_and_target_length() {
 526   update_young_list_max_and_target_length(get_new_prediction(_rs_lengths_seq));
 527 }
 528 
 529 void G1CollectorPolicy::update_young_list_max_and_target_length(size_t rs_lengths) {
 530   update_young_list_target_length(rs_lengths);
 531   update_max_gc_locker_expansion();

 532 }
 533 
 534 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
 535   _young_list_target_length = bounded_young_list_target_length(rs_lengths);


 536 }
 537 
 538 void G1CollectorPolicy::update_young_list_target_length() {
 539   update_young_list_target_length(get_new_prediction(_rs_lengths_seq));
 540 }
 541 
 542 uint G1CollectorPolicy::bounded_young_list_target_length(size_t rs_lengths) const {
 543   // Calculate the absolute and desired min bounds.
 544 
 545   // This is how many young regions we already have (currently: the survivors).
 546   uint base_min_length = recorded_survivor_regions();
 547   uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
 548   // This is the absolute minimum young length. Ensure that we
 549   // will at least have one eden region available for allocation.
 550   uint absolute_min_length = base_min_length + MAX2(_g1->young_list()->eden_length(), (uint)1);
 551   // If we shrank the young list target it should not shrink below the current size.
 552   desired_min_length = MAX2(desired_min_length, absolute_min_length);
 553   // Calculate the absolute and desired max bounds.
 554 
 555   // We will try our best not to "eat" into the reserve.
 556   uint absolute_max_length = 0;
 557   if (_free_regions_at_end_of_collection > _reserve_regions) {
 558     absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
 559   }
 560   uint desired_max_length = calculate_young_list_desired_max_length();
 561   if (desired_max_length > absolute_max_length) {
 562     desired_max_length = absolute_max_length;
 563   }
 564 
 565   uint young_list_target_length = 0;
 566   if (adaptive_young_list_length()) {
 567     if (collector_state()->gcs_are_young()) {
 568       young_list_target_length =
 569                         calculate_young_list_target_length(rs_lengths,
 570                                                            base_min_length,
 571                                                            desired_min_length,
 572                                                            desired_max_length);
 573     } else {
 574       // Don't calculate anything and let the code below bound it to
 575       // the desired_min_length, i.e., do the next GC as soon as
 576       // possible to maximize how many old regions we can add to it.
 577     }
 578   } else {
 579     // The user asked for a fixed young gen so we'll fix the young gen
 580     // whether the next GC is young or mixed.
 581     young_list_target_length = _young_list_fixed_length;
 582   }
 583 











 584   // Make sure we don't go over the desired max length, nor under the
 585   // desired min length. In case they clash, desired_min_length wins
 586   // which is why that test is second.
 587   if (young_list_target_length > desired_max_length) {
 588     young_list_target_length = desired_max_length;
 589   }
 590   if (young_list_target_length < desired_min_length) {
 591     young_list_target_length = desired_min_length;
 592   }
 593 
 594   assert(young_list_target_length > recorded_survivor_regions(),
 595          "we should be able to allocate at least one eden region");
 596   assert(young_list_target_length >= absolute_min_length, "post-condition");
 597 
 598   return young_list_target_length;

 599 }
 600 
 601 uint
 602 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
 603                                                      uint base_min_length,
 604                                                      uint desired_min_length,
 605                                                      uint desired_max_length) const {
 606   assert(adaptive_young_list_length(), "pre-condition");
 607   assert(collector_state()->gcs_are_young(), "only call this for young GCs");
 608 
 609   // In case some edge-condition makes the desired max length too small...
 610   if (desired_max_length <= desired_min_length) {
 611     return desired_min_length;
 612   }
 613 
 614   // We'll adjust min_young_length and max_young_length not to include
 615   // the already allocated young regions (i.e., so they reflect the
 616   // min and max eden regions we'll allocate). The base_min_length
 617   // will be reflected in the predictions by the
 618   // survivor_regions_evac_time prediction.
 619   assert(desired_min_length > base_min_length, "invariant");
 620   uint min_young_length = desired_min_length - base_min_length;
 621   assert(desired_max_length > base_min_length, "invariant");
 622   uint max_young_length = desired_max_length - base_min_length;
 623 
 624   double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
 625   double survivor_regions_evac_time = predict_survivor_regions_evac_time();
 626   size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
 627   size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
 628   size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
 629   double base_time_ms =
 630     predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
 631     survivor_regions_evac_time;
 632   uint available_free_regions = _free_regions_at_end_of_collection;
 633   uint base_free_regions = 0;
 634   if (available_free_regions > _reserve_regions) {
 635     base_free_regions = available_free_regions - _reserve_regions;
 636   }
 637 
 638   // Here, we will make sure that the shortest young length that
 639   // makes sense fits within the target pause time.
 640 
 641   if (predict_will_fit(min_young_length, base_time_ms,
 642                        base_free_regions, target_pause_time_ms)) {
 643     // The shortest young length will fit into the target pause time;
 644     // we'll now check whether the absolute maximum number of young
 645     // regions will fit in the target pause time. If not, we'll do
 646     // a binary search between min_young_length and max_young_length.
 647     if (predict_will_fit(max_young_length, base_time_ms,
 648                          base_free_regions, target_pause_time_ms)) {
 649       // The maximum young length will fit into the target pause time.
 650       // We are done so set min young length to the maximum length (as
 651       // the result is assumed to be returned in min_young_length).
 652       min_young_length = max_young_length;
 653     } else {
 654       // The maximum possible number of young regions will not fit within
 655       // the target pause time so we'll search for the optimal
 656       // length. The loop invariants are:
 657       //
 658       // min_young_length < max_young_length
 659       // min_young_length is known to fit into the target pause time
 660       // max_young_length is known not to fit into the target pause time
 661       //
 662       // Going into the loop we know the above hold as we've just
 663       // checked them. Every time around the loop we check whether
 664       // the middle value between min_young_length and
 665       // max_young_length fits into the target pause time. If it
 666       // does, it becomes the new min. If it doesn't, it becomes
 667       // the new max. This way we maintain the loop invariants.
 668 
 669       assert(min_young_length < max_young_length, "invariant");
 670       uint diff = (max_young_length - min_young_length) / 2;
 671       while (diff > 0) {
 672         uint young_length = min_young_length + diff;
 673         if (predict_will_fit(young_length, base_time_ms,
 674                              base_free_regions, target_pause_time_ms)) {
 675           min_young_length = young_length;
 676         } else {
 677           max_young_length = young_length;
 678         }
 679         assert(min_young_length <  max_young_length, "invariant");
 680         diff = (max_young_length - min_young_length) / 2;
 681       }
 682       // The results is min_young_length which, according to the
 683       // loop invariants, should fit within the target pause time.
 684 
 685       // These are the post-conditions of the binary search above:
 686       assert(min_young_length < max_young_length,
 687              "otherwise we should have discovered that max_young_length "
 688              "fits into the pause target and not done the binary search");
 689       assert(predict_will_fit(min_young_length, base_time_ms,
 690                               base_free_regions, target_pause_time_ms),
 691              "min_young_length, the result of the binary search, should "
 692              "fit into the pause target");
 693       assert(!predict_will_fit(min_young_length + 1, base_time_ms,
 694                                base_free_regions, target_pause_time_ms),
 695              "min_young_length, the result of the binary search, should be "
 696              "optimal, so no larger length should fit into the pause target");
 697     }
 698   } else {
 699     // Even the minimum length doesn't fit into the pause time
 700     // target, return it as the result nevertheless.
 701   }
 702   return base_min_length + min_young_length;
 703 }
 704 
 705 double G1CollectorPolicy::predict_survivor_regions_evac_time() const {
 706   double survivor_regions_evac_time = 0.0;
 707   for (HeapRegion * r = _recorded_survivor_head;
 708        r != NULL && r != _recorded_survivor_tail->get_next_young_region();
 709        r = r->get_next_young_region()) {
 710     survivor_regions_evac_time += predict_region_elapsed_time_ms(r, collector_state()->gcs_are_young());
 711   }
 712   return survivor_regions_evac_time;
 713 }
 714 
 715 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
 716   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
 717 
 718   size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
 719   if (rs_lengths > _rs_lengths_prediction) {
 720     // add 10% to avoid having to recalculate often
 721     size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
 722     update_rs_lengths_prediction(rs_lengths_prediction);
 723 
 724     update_young_list_max_and_target_length(rs_lengths_prediction);
 725   }
 726 }
 727 
 728 void G1CollectorPolicy::update_rs_lengths_prediction() {
 729   update_rs_lengths_prediction(get_new_prediction(_rs_lengths_seq));
 730 }
 731 
 732 void G1CollectorPolicy::update_rs_lengths_prediction(size_t prediction) {
 733   if (collector_state()->gcs_are_young() && adaptive_young_list_length()) {
 734     _rs_lengths_prediction = prediction;
 735   }
 736 }
 737 
 738 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
 739                                                bool is_tlab,
 740                                                bool* gc_overhead_limit_was_exceeded) {
 741   guarantee(false, "Not using this policy feature yet.");
 742   return NULL;
 743 }
 744 
 745 // This method controls how a collector handles one or more
 746 // of its generations being fully allocated.
 747 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
 748                                                        bool is_tlab) {
 749   guarantee(false, "Not using this policy feature yet.");
 750   return NULL;
 751 }
 752 
 753 
 754 #ifndef PRODUCT
 755 bool G1CollectorPolicy::verify_young_ages() {
 756   HeapRegion* head = _g1->young_list()->first_region();
 757   return
 758     verify_young_ages(head, _short_lived_surv_rate_group);
 759   // also call verify_young_ages on any additional surv rate groups
 760 }
 761 
 762 bool
 763 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
 764                                      SurvRateGroup *surv_rate_group) {
 765   guarantee( surv_rate_group != NULL, "pre-condition" );
 766 
 767   const char* name = surv_rate_group->name();
 768   bool ret = true;
 769   int prev_age = -1;
 770 
 771   for (HeapRegion* curr = head;
 772        curr != NULL;
 773        curr = curr->get_next_young_region()) {
 774     SurvRateGroup* group = curr->surv_rate_group();
 775     if (group == NULL && !curr->is_survivor()) {
 776       gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
 777       ret = false;
 778     }
 779 
 780     if (surv_rate_group == group) {
 781       int age = curr->age_in_surv_rate_group();
 782 
 783       if (age < 0) {
 784         gclog_or_tty->print_cr("## %s: encountered negative age", name);
 785         ret = false;
 786       }
 787 
 788       if (age <= prev_age) {
 789         gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
 790                                "(%d, %d)", name, age, prev_age);
 791         ret = false;
 792       }
 793       prev_age = age;
 794     }
 795   }
 796 
 797   return ret;
 798 }
 799 #endif // PRODUCT
 800 
 801 void G1CollectorPolicy::record_full_collection_start() {
 802   _full_collection_start_sec = os::elapsedTime();
 803   record_heap_size_info_at_start(true /* full */);
 804   // Release the future to-space so that it is available for compaction into.
 805   collector_state()->set_full_collection(true);
 806 }
 807 
 808 void G1CollectorPolicy::record_full_collection_end() {
 809   // Consider this like a collection pause for the purposes of allocation
 810   // since last pause.
 811   double end_sec = os::elapsedTime();
 812   double full_gc_time_sec = end_sec - _full_collection_start_sec;
 813   double full_gc_time_ms = full_gc_time_sec * 1000.0;
 814 
 815   _trace_old_gen_time_data.record_full_collection(full_gc_time_ms);
 816 
 817   update_recent_gc_times(end_sec, full_gc_time_ms);
 818 
 819   collector_state()->set_full_collection(false);
 820 
 821   // "Nuke" the heuristics that control the young/mixed GC
 822   // transitions and make sure we start with young GCs after the Full GC.
 823   collector_state()->set_gcs_are_young(true);
 824   collector_state()->set_last_young_gc(false);
 825   collector_state()->set_initiate_conc_mark_if_possible(need_to_start_conc_mark("end of Full GC", 0));
 826   collector_state()->set_during_initial_mark_pause(false);
 827   collector_state()->set_in_marking_window(false);
 828   collector_state()->set_in_marking_window_im(false);
 829 
 830   _short_lived_surv_rate_group->start_adding_regions();
 831   // also call this on any additional surv rate groups
 832 
 833   record_survivor_regions(0, NULL, NULL);
 834 
 835   _free_regions_at_end_of_collection = _g1->num_free_regions();
 836   // Reset survivors SurvRateGroup.
 837   _survivor_surv_rate_group->reset();
 838   update_young_list_max_and_target_length();
 839   update_rs_lengths_prediction();
 840   _collectionSetChooser->clear();




 841 }
 842 
 843 void G1CollectorPolicy::record_stop_world_start() {
 844   _stop_world_start = os::elapsedTime();
 845 }
 846 
 847 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
 848   // We only need to do this here as the policy will only be applied
 849   // to the GC we're about to start. so, no point is calculating this
 850   // every time we calculate / recalculate the target young length.
 851   update_survivors_policy();
 852 
 853   assert(_g1->used() == _g1->recalculate_used(),
 854          "sanity, used: " SIZE_FORMAT " recalculate_used: " SIZE_FORMAT,
 855          _g1->used(), _g1->recalculate_used());
 856 
 857   double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
 858   _trace_young_gen_time_data.record_start_collection(s_w_t_ms);
 859   _stop_world_start = 0.0;
 860 
 861   record_heap_size_info_at_start(false /* full */);
 862 
 863   phase_times()->record_cur_collection_start_sec(start_time_sec);
 864   _pending_cards = _g1->pending_card_num();
 865 
 866   _collection_set_bytes_used_before = 0;
 867   _bytes_copied_during_gc = 0;
 868 
 869   collector_state()->set_last_gc_was_young(false);
 870 
 871   // do that for any other surv rate groups
 872   _short_lived_surv_rate_group->stop_adding_regions();
 873   _survivors_age_table.clear();
 874 
 875   assert( verify_young_ages(), "region age verification" );
 876 }
 877 
 878 void G1CollectorPolicy::record_concurrent_mark_init_end(double
 879                                                    mark_init_elapsed_time_ms) {
 880   collector_state()->set_during_marking(true);
 881   assert(!collector_state()->initiate_conc_mark_if_possible(), "we should have cleared it by now");
 882   collector_state()->set_during_initial_mark_pause(false);
 883   _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
 884 }
 885 
 886 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
 887   _mark_remark_start_sec = os::elapsedTime();
 888   collector_state()->set_during_marking(false);
 889 }
 890 
 891 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
 892   double end_time_sec = os::elapsedTime();
 893   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
 894   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
 895   _cur_mark_stop_world_time_ms += elapsed_time_ms;
 896   _prev_collection_pause_end_ms += elapsed_time_ms;
 897 
 898   _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec);
 899 }
 900 
 901 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
 902   _mark_cleanup_start_sec = os::elapsedTime();
 903 }
 904 
 905 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
 906   bool should_continue_with_reclaim = next_gc_should_be_mixed("request last young-only gc",
 907                                                               "skip last young-only gc");
 908   collector_state()->set_last_young_gc(should_continue_with_reclaim);




 909   collector_state()->set_in_marking_window(false);
 910 }
 911 
 912 void G1CollectorPolicy::record_concurrent_pause() {
 913   if (_stop_world_start > 0.0) {
 914     double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
 915     _trace_young_gen_time_data.record_yield_time(yield_ms);
 916   }
 917 }
 918 
 919 double G1CollectorPolicy::average_time_ms(G1GCPhaseTimes::GCParPhases phase) const {
 920   return phase_times()->average_time_ms(phase);
 921 }
 922 
 923 double G1CollectorPolicy::young_other_time_ms() const {
 924   return phase_times()->young_cset_choice_time_ms() +
 925          phase_times()->young_free_cset_time_ms();
 926 }
 927 
 928 double G1CollectorPolicy::non_young_other_time_ms() const {
 929   return phase_times()->non_young_cset_choice_time_ms() +
 930          phase_times()->non_young_free_cset_time_ms();
 931 
 932 }
 933 
 934 double G1CollectorPolicy::other_time_ms(double pause_time_ms) const {
 935   return pause_time_ms -
 936          average_time_ms(G1GCPhaseTimes::UpdateRS) -
 937          average_time_ms(G1GCPhaseTimes::ScanRS) -
 938          average_time_ms(G1GCPhaseTimes::ObjCopy) -
 939          average_time_ms(G1GCPhaseTimes::Termination);
 940 }
 941 
 942 double G1CollectorPolicy::constant_other_time_ms(double pause_time_ms) const {
 943   return other_time_ms(pause_time_ms) - young_other_time_ms() - non_young_other_time_ms();
 944 }
 945 
 946 bool G1CollectorPolicy::about_to_start_mixed_phase() const {
 947   return _g1->concurrent_mark()->cmThread()->during_cycle() || collector_state()->last_young_gc();
 948 }
 949 
 950 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
 951   if (about_to_start_mixed_phase()) {
 952     return false;
 953   }
 954 
 955   size_t marking_initiating_used_threshold =
 956     (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
 957   size_t cur_used_bytes = _g1->non_young_capacity_bytes();
 958   size_t alloc_byte_size = alloc_word_size * HeapWordSize;

 959 
 960   if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
 961     if (collector_state()->gcs_are_young() && !collector_state()->last_young_gc()) {
 962       ergo_verbose5(ErgoConcCycles,
 963         "request concurrent cycle initiation",
 964         ergo_format_reason("occupancy higher than threshold")
 965         ergo_format_byte("occupancy")
 966         ergo_format_byte("allocation request")
 967         ergo_format_byte_perc("threshold")
 968         ergo_format_str("source"),
 969         cur_used_bytes,
 970         alloc_byte_size,
 971         marking_initiating_used_threshold,
 972         (double) InitiatingHeapOccupancyPercent,
 973         source);
 974       return true;
 975     } else {
 976       ergo_verbose5(ErgoConcCycles,
 977         "do not request concurrent cycle initiation",
 978         ergo_format_reason("still doing mixed collections")
 979         ergo_format_byte("occupancy")
 980         ergo_format_byte("allocation request")
 981         ergo_format_byte_perc("threshold")
 982         ergo_format_str("source"),
 983         cur_used_bytes,
 984         alloc_byte_size,
 985         marking_initiating_used_threshold,
 986         (double) InitiatingHeapOccupancyPercent,
 987         source);
 988     }
 989   }
 990 
 991   return false;
 992 }
 993 
 994 // Anything below that is considered to be zero
 995 #define MIN_TIMER_GRANULARITY 0.0000001
 996 
 997 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, size_t cards_scanned) {
 998   double end_time_sec = os::elapsedTime();
 999   assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
1000          "otherwise, the subtraction below does not make sense");
1001   size_t rs_size =
1002             _cur_collection_pause_used_regions_at_start - cset_region_length();
1003   size_t cur_used_bytes = _g1->used();
1004   assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1005   bool last_pause_included_initial_mark = false;
1006   bool update_stats = !_g1->evacuation_failed();
1007 
1008 #ifndef PRODUCT
1009   if (G1YoungSurvRateVerbose) {
1010     gclog_or_tty->cr();
1011     _short_lived_surv_rate_group->print();
1012     // do that for any other surv rate groups too
1013   }
1014 #endif // PRODUCT
1015 


1016   last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
1017   if (last_pause_included_initial_mark) {
1018     record_concurrent_mark_init_end(0.0);
1019   } else {
1020     maybe_start_marking();
1021   }
1022 
1023   _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0, end_time_sec);
1024 
1025   if (update_stats) {
1026     _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times());
1027     // this is where we update the allocation rate of the application
1028     double app_time_ms =
1029       (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
1030     if (app_time_ms < MIN_TIMER_GRANULARITY) {
1031       // This usually happens due to the timer not having the required
1032       // granularity. Some Linuxes are the usual culprits.
1033       // We'll just set it to something (arbitrarily) small.
1034       app_time_ms = 1.0;
1035     }



1036     // We maintain the invariant that all objects allocated by mutator
1037     // threads will be allocated out of eden regions. So, we can use
1038     // the eden region number allocated since the previous GC to
1039     // calculate the application's allocate rate. The only exception
1040     // to that is humongous objects that are allocated separately. But
1041     // given that humongous object allocations do not really affect
1042     // either the pause's duration nor when the next pause will take
1043     // place we can safely ignore them here.
1044     uint regions_allocated = eden_cset_region_length();
1045     double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1046     _alloc_rate_ms_seq->add(alloc_rate_ms);
1047 
1048     double interval_ms =
1049       (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1050     update_recent_gc_times(end_time_sec, pause_time_ms);
1051     _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1052     if (recent_avg_pause_time_ratio() < 0.0 ||
1053         (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1054       // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1055       // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1056       if (_recent_avg_pause_time_ratio < 0.0) {
1057         _recent_avg_pause_time_ratio = 0.0;
1058       } else {
1059         assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1060         _recent_avg_pause_time_ratio = 1.0;
1061       }
1062     }
1063   }
1064 
1065   bool new_in_marking_window = collector_state()->in_marking_window();
1066   bool new_in_marking_window_im = false;
1067   if (last_pause_included_initial_mark) {
1068     new_in_marking_window = true;
1069     new_in_marking_window_im = true;
1070   }
1071 
1072   if (collector_state()->last_young_gc()) {
1073     // This is supposed to to be the "last young GC" before we start
1074     // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1075     assert(!last_pause_included_initial_mark, "The last young GC is not allowed to be an initial mark GC");
1076 
1077     if (next_gc_should_be_mixed("start mixed GCs",
1078                                 "do not start mixed GCs")) {
1079       collector_state()->set_gcs_are_young(false);



1080     }
1081 
1082     collector_state()->set_last_young_gc(false);
1083   }
1084 
1085   if (!collector_state()->last_gc_was_young()) {
1086     // This is a mixed GC. Here we decide whether to continue doing
1087     // mixed GCs or not.
1088 
1089     if (!next_gc_should_be_mixed("continue mixed GCs",
1090                                  "do not continue mixed GCs")) {
1091       collector_state()->set_gcs_are_young(true);
1092 
1093       maybe_start_marking();
1094     }
1095   }
1096 
1097   _short_lived_surv_rate_group->start_adding_regions();
1098   // Do that for any other surv rate groups
1099 
1100   if (update_stats) {
1101     double cost_per_card_ms = 0.0;
1102     double cost_scan_hcc = average_time_ms(G1GCPhaseTimes::ScanHCC);
1103     if (_pending_cards > 0) {
1104       cost_per_card_ms = (average_time_ms(G1GCPhaseTimes::UpdateRS) - cost_scan_hcc) / (double) _pending_cards;
1105       _cost_per_card_ms_seq->add(cost_per_card_ms);
1106     }
1107     _cost_scan_hcc_seq->add(cost_scan_hcc);
1108 
1109     double cost_per_entry_ms = 0.0;
1110     if (cards_scanned > 10) {
1111       cost_per_entry_ms = average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
1112       if (collector_state()->last_gc_was_young()) {
1113         _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1114       } else {
1115         _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1116       }
1117     }
1118 
1119     if (_max_rs_lengths > 0) {
1120       double cards_per_entry_ratio =
1121         (double) cards_scanned / (double) _max_rs_lengths;
1122       if (collector_state()->last_gc_was_young()) {
1123         _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1124       } else {
1125         _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1126       }
1127     }
1128 
1129     // This is defensive. For a while _max_rs_lengths could get
1130     // smaller than _recorded_rs_lengths which was causing
1131     // rs_length_diff to get very large and mess up the RSet length
1132     // predictions. The reason was unsafe concurrent updates to the
1133     // _inc_cset_recorded_rs_lengths field which the code below guards
1134     // against (see CR 7118202). This bug has now been fixed (see CR
1135     // 7119027). However, I'm still worried that
1136     // _inc_cset_recorded_rs_lengths might still end up somewhat
1137     // inaccurate. The concurrent refinement thread calculates an
1138     // RSet's length concurrently with other CR threads updating it
1139     // which might cause it to calculate the length incorrectly (if,
1140     // say, it's in mid-coarsening). So I'll leave in the defensive
1141     // conditional below just in case.
1142     size_t rs_length_diff = 0;
1143     if (_max_rs_lengths > _recorded_rs_lengths) {
1144       rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1145     }
1146     _rs_length_diff_seq->add((double) rs_length_diff);
1147 
1148     size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1149     size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1150     double cost_per_byte_ms = 0.0;
1151 
1152     if (copied_bytes > 0) {
1153       cost_per_byte_ms = average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
1154       if (collector_state()->in_marking_window()) {
1155         _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1156       } else {
1157         _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1158       }
1159     }
1160 
1161     if (young_cset_region_length() > 0) {
1162       _young_other_cost_per_region_ms_seq->add(young_other_time_ms() /
1163                                                young_cset_region_length());
1164     }
1165 
1166     if (old_cset_region_length() > 0) {
1167       _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms() /
1168                                                    old_cset_region_length());
1169     }
1170 
1171     _constant_other_time_ms_seq->add(constant_other_time_ms(pause_time_ms));
1172 
1173     _pending_cards_seq->add((double) _pending_cards);
1174     _rs_lengths_seq->add((double) _max_rs_lengths);
1175   }
1176 
1177   collector_state()->set_in_marking_window(new_in_marking_window);
1178   collector_state()->set_in_marking_window_im(new_in_marking_window_im);
1179   _free_regions_at_end_of_collection = _g1->num_free_regions();
1180   update_young_list_max_and_target_length();




1181   update_rs_lengths_prediction();
1182 





1183   // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1184   double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1185 
1186   double scan_hcc_time_ms = average_time_ms(G1GCPhaseTimes::ScanHCC);
1187 
1188   if (update_rs_time_goal_ms < scan_hcc_time_ms) {
1189     ergo_verbose2(ErgoTiming,
1190                   "adjust concurrent refinement thresholds",
1191                   ergo_format_reason("Scanning the HCC expected to take longer than Update RS time goal")
1192                   ergo_format_ms("Update RS time goal")
1193                   ergo_format_ms("Scan HCC time"),
1194                   update_rs_time_goal_ms,
1195                   scan_hcc_time_ms);
1196 
1197     update_rs_time_goal_ms = 0;
1198   } else {
1199     update_rs_time_goal_ms -= scan_hcc_time_ms;
1200   }
1201   adjust_concurrent_refinement(average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms,
1202                                phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS),
1203                                update_rs_time_goal_ms);
1204 
1205   _collectionSetChooser->verify();
1206 }
1207 















































1208 #define EXT_SIZE_FORMAT "%.1f%s"
1209 #define EXT_SIZE_PARAMS(bytes)                                  \
1210   byte_size_in_proper_unit((double)(bytes)),                    \
1211   proper_unit_for_byte_size((bytes))
1212 
1213 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1214   YoungList* young_list = _g1->young_list();
1215   _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1216   _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1217   _heap_capacity_bytes_before_gc = _g1->capacity();
1218   _heap_used_bytes_before_gc = _g1->used();
1219   _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1220 
1221   _eden_capacity_bytes_before_gc =
1222          (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1223 
1224   if (full) {
1225     _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1226   }
1227 }
1228 
1229 void G1CollectorPolicy::print_heap_transition(size_t bytes_before) const {
1230   size_t bytes_after = _g1->used();
1231   size_t capacity = _g1->capacity();
1232 
1233   gclog_or_tty->print(" " SIZE_FORMAT "%s->" SIZE_FORMAT "%s(" SIZE_FORMAT "%s)",
1234       byte_size_in_proper_unit(bytes_before),
1235       proper_unit_for_byte_size(bytes_before),
1236       byte_size_in_proper_unit(bytes_after),
1237       proper_unit_for_byte_size(bytes_after),
1238       byte_size_in_proper_unit(capacity),
1239       proper_unit_for_byte_size(capacity));
1240 }
1241 
1242 void G1CollectorPolicy::print_heap_transition() const {
1243   print_heap_transition(_heap_used_bytes_before_gc);
1244 }
1245 
1246 void G1CollectorPolicy::print_detailed_heap_transition(bool full) const {
1247   YoungList* young_list = _g1->young_list();
1248 
1249   size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1250   size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1251   size_t heap_used_bytes_after_gc = _g1->used();
1252 
1253   size_t heap_capacity_bytes_after_gc = _g1->capacity();
1254   size_t eden_capacity_bytes_after_gc =
1255     (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1256 
1257   gclog_or_tty->print(
1258     "   [Eden: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->" EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ") "
1259     "Survivors: " EXT_SIZE_FORMAT "->" EXT_SIZE_FORMAT " "
1260     "Heap: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->"
1261     EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")]",
1262     EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1263     EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1264     EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1265     EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1266     EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1267     EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1268     EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1269     EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1270     EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1271     EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1272 
1273   if (full) {
1274     MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1275   }
1276 
1277   gclog_or_tty->cr();
1278 }
1279 
1280 void G1CollectorPolicy::print_phases(double pause_time_sec) {
1281   phase_times()->print(pause_time_sec);
1282 }
1283 
1284 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1285                                                      double update_rs_processed_buffers,
1286                                                      double goal_ms) {
1287   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1288   ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1289 
1290   if (G1UseAdaptiveConcRefinement) {
1291     const int k_gy = 3, k_gr = 6;
1292     const double inc_k = 1.1, dec_k = 0.9;
1293 
1294     int g = cg1r->green_zone();
1295     if (update_rs_time > goal_ms) {
1296       g = (int)(g * dec_k);  // Can become 0, that's OK. That would mean a mutator-only processing.
1297     } else {
1298       if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1299         g = (int)MAX2(g * inc_k, g + 1.0);
1300       }
1301     }
1302     // Change the refinement threads params
1303     cg1r->set_green_zone(g);
1304     cg1r->set_yellow_zone(g * k_gy);
1305     cg1r->set_red_zone(g * k_gr);
1306     cg1r->reinitialize_threads();
1307 
1308     int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * _predictor.sigma()), 1);
1309     int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1310                                     cg1r->yellow_zone());
1311     // Change the barrier params
1312     dcqs.set_process_completed_threshold(processing_threshold);
1313     dcqs.set_max_completed_queue(cg1r->red_zone());
1314   }
1315 
1316   int curr_queue_size = dcqs.completed_buffers_num();
1317   if (curr_queue_size >= cg1r->yellow_zone()) {
1318     dcqs.set_completed_queue_padding(curr_queue_size);
1319   } else {
1320     dcqs.set_completed_queue_padding(0);
1321   }
1322   dcqs.notify_if_necessary();
1323 }
1324 
1325 size_t G1CollectorPolicy::predict_rs_length_diff() const {
1326   return (size_t) get_new_prediction(_rs_length_diff_seq);
1327 }
1328 
1329 double G1CollectorPolicy::predict_alloc_rate_ms() const {
1330   return get_new_prediction(_alloc_rate_ms_seq);
1331 }
1332 
1333 double G1CollectorPolicy::predict_cost_per_card_ms() const {
1334   return get_new_prediction(_cost_per_card_ms_seq);
1335 }
1336 
1337 double G1CollectorPolicy::predict_scan_hcc_ms() const {
1338   return get_new_prediction(_cost_scan_hcc_seq);
1339 }
1340 
1341 double G1CollectorPolicy::predict_rs_update_time_ms(size_t pending_cards) const {
1342   return pending_cards * predict_cost_per_card_ms() + predict_scan_hcc_ms();
1343 }
1344 
1345 double G1CollectorPolicy::predict_young_cards_per_entry_ratio() const {
1346   return get_new_prediction(_young_cards_per_entry_ratio_seq);
1347 }
1348 
1349 double G1CollectorPolicy::predict_mixed_cards_per_entry_ratio() const {
1350   if (_mixed_cards_per_entry_ratio_seq->num() < 2) {
1351     return predict_young_cards_per_entry_ratio();
1352   } else {
1353     return get_new_prediction(_mixed_cards_per_entry_ratio_seq);
1354   }
1355 }
1356 
1357 size_t G1CollectorPolicy::predict_young_card_num(size_t rs_length) const {
1358   return (size_t) (rs_length * predict_young_cards_per_entry_ratio());
1359 }
1360 
1361 size_t G1CollectorPolicy::predict_non_young_card_num(size_t rs_length) const {
1362   return (size_t)(rs_length * predict_mixed_cards_per_entry_ratio());
1363 }
1364 
1365 double G1CollectorPolicy::predict_rs_scan_time_ms(size_t card_num) const {
1366   if (collector_state()->gcs_are_young()) {
1367     return card_num * get_new_prediction(_cost_per_entry_ms_seq);
1368   } else {
1369     return predict_mixed_rs_scan_time_ms(card_num);
1370   }
1371 }
1372 
1373 double G1CollectorPolicy::predict_mixed_rs_scan_time_ms(size_t card_num) const {
1374   if (_mixed_cost_per_entry_ms_seq->num() < 3) {
1375     return card_num * get_new_prediction(_cost_per_entry_ms_seq);
1376   } else {
1377     return card_num * get_new_prediction(_mixed_cost_per_entry_ms_seq);
1378   }
1379 }
1380 
1381 double G1CollectorPolicy::predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const {
1382   if (_cost_per_byte_ms_during_cm_seq->num() < 3) {
1383     return (1.1 * bytes_to_copy) * get_new_prediction(_cost_per_byte_ms_seq);
1384   } else {
1385     return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_during_cm_seq);
1386   }
1387 }
1388 
1389 double G1CollectorPolicy::predict_object_copy_time_ms(size_t bytes_to_copy) const {
1390   if (collector_state()->during_concurrent_mark()) {
1391     return predict_object_copy_time_ms_during_cm(bytes_to_copy);
1392   } else {
1393     return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_seq);
1394   }
1395 }
1396 
1397 double G1CollectorPolicy::predict_constant_other_time_ms() const {
1398   return get_new_prediction(_constant_other_time_ms_seq);
1399 }
1400 
1401 double G1CollectorPolicy::predict_young_other_time_ms(size_t young_num) const {
1402   return young_num * get_new_prediction(_young_other_cost_per_region_ms_seq);
1403 }
1404 
1405 double G1CollectorPolicy::predict_non_young_other_time_ms(size_t non_young_num) const {
1406   return non_young_num * get_new_prediction(_non_young_other_cost_per_region_ms_seq);
1407 }
1408 
1409 double G1CollectorPolicy::predict_remark_time_ms() const {
1410   return get_new_prediction(_concurrent_mark_remark_times_ms);
1411 }
1412 
1413 double G1CollectorPolicy::predict_cleanup_time_ms() const {
1414   return get_new_prediction(_concurrent_mark_cleanup_times_ms);
1415 }
1416 
1417 double G1CollectorPolicy::predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const {
1418   TruncatedSeq* seq = surv_rate_group->get_seq(age);
1419   guarantee(seq->num() > 0, "There should be some young gen survivor samples available. Tried to access with age %d", age);
1420   double pred = get_new_prediction(seq);
1421   if (pred > 1.0) {
1422     pred = 1.0;
1423   }
1424   return pred;
1425 }
1426 
1427 double G1CollectorPolicy::predict_yg_surv_rate(int age) const {
1428   return predict_yg_surv_rate(age, _short_lived_surv_rate_group);
1429 }
1430 
1431 double G1CollectorPolicy::accum_yg_surv_rate_pred(int age) const {
1432   return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
1433 }
1434 
1435 double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1436                                                        size_t scanned_cards) const {
1437   return
1438     predict_rs_update_time_ms(pending_cards) +
1439     predict_rs_scan_time_ms(scanned_cards) +
1440     predict_constant_other_time_ms();
1441 }
1442 
1443 double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) const {
1444   size_t rs_length = predict_rs_length_diff();
1445   size_t card_num;
1446   if (collector_state()->gcs_are_young()) {
1447     card_num = predict_young_card_num(rs_length);
1448   } else {
1449     card_num = predict_non_young_card_num(rs_length);
1450   }
1451   return predict_base_elapsed_time_ms(pending_cards, card_num);
1452 }
1453 
1454 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) const {
1455   size_t bytes_to_copy;
1456   if (hr->is_marked())
1457     bytes_to_copy = hr->max_live_bytes();
1458   else {
1459     assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1460     int age = hr->age_in_surv_rate_group();
1461     double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1462     bytes_to_copy = (size_t) (hr->used() * yg_surv_rate);
1463   }
1464   return bytes_to_copy;
1465 }
1466 
1467 double G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1468                                                          bool for_young_gc) const {
1469   size_t rs_length = hr->rem_set()->occupied();
1470   size_t card_num;
1471 
1472   // Predicting the number of cards is based on which type of GC
1473   // we're predicting for.
1474   if (for_young_gc) {
1475     card_num = predict_young_card_num(rs_length);
1476   } else {
1477     card_num = predict_non_young_card_num(rs_length);
1478   }
1479   size_t bytes_to_copy = predict_bytes_to_copy(hr);
1480 
1481   double region_elapsed_time_ms =
1482     predict_rs_scan_time_ms(card_num) +
1483     predict_object_copy_time_ms(bytes_to_copy);
1484 
1485   // The prediction of the "other" time for this region is based
1486   // upon the region type and NOT the GC type.
1487   if (hr->is_young()) {
1488     region_elapsed_time_ms += predict_young_other_time_ms(1);
1489   } else {
1490     region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1491   }
1492   return region_elapsed_time_ms;
1493 }
1494 
1495 void G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1496                                                  uint survivor_cset_region_length) {
1497   _eden_cset_region_length     = eden_cset_region_length;
1498   _survivor_cset_region_length = survivor_cset_region_length;
1499   _old_cset_region_length      = 0;
1500 }
1501 
1502 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1503   _recorded_rs_lengths = rs_lengths;
1504 }
1505 
1506 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1507                                                double elapsed_ms) {
1508   _recent_gc_times_ms->add(elapsed_ms);
1509   _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1510   _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1511 }
1512 
1513 size_t G1CollectorPolicy::expansion_amount() const {
1514   double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1515   double threshold = _gc_overhead_perc;
1516   if (recent_gc_overhead > threshold) {
1517     // We will double the existing space, or take
1518     // G1ExpandByPercentOfAvailable % of the available expansion
1519     // space, whichever is smaller, bounded below by a minimum
1520     // expansion (unless that's all that's left.)
1521     const size_t min_expand_bytes = 1*M;
1522     size_t reserved_bytes = _g1->max_capacity();
1523     size_t committed_bytes = _g1->capacity();
1524     size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1525     size_t expand_bytes;
1526     size_t expand_bytes_via_pct =
1527       uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1528     expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1529     expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1530     expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1531 
1532     ergo_verbose5(ErgoHeapSizing,
1533                   "attempt heap expansion",
1534                   ergo_format_reason("recent GC overhead higher than "
1535                                      "threshold after GC")
1536                   ergo_format_perc("recent GC overhead")
1537                   ergo_format_perc("threshold")
1538                   ergo_format_byte("uncommitted")
1539                   ergo_format_byte_perc("calculated expansion amount"),
1540                   recent_gc_overhead, threshold,
1541                   uncommitted_bytes,
1542                   expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1543 
1544     return expand_bytes;
1545   } else {
1546     return 0;
1547   }
1548 }
1549 
1550 void G1CollectorPolicy::print_tracing_info() const {
1551   _trace_young_gen_time_data.print();
1552   _trace_old_gen_time_data.print();
1553 }
1554 
1555 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1556 #ifndef PRODUCT
1557   _short_lived_surv_rate_group->print_surv_rate_summary();
1558   // add this call for any other surv rate groups
1559 #endif // PRODUCT
1560 }
1561 
1562 bool G1CollectorPolicy::is_young_list_full() const {
1563   uint young_list_length = _g1->young_list()->length();
1564   uint young_list_target_length = _young_list_target_length;
1565   return young_list_length >= young_list_target_length;
1566 }
1567 
1568 bool G1CollectorPolicy::can_expand_young_list() const {
1569   uint young_list_length = _g1->young_list()->length();
1570   uint young_list_max_length = _young_list_max_length;
1571   return young_list_length < young_list_max_length;
1572 }
1573 
1574 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1575   uint expansion_region_num = 0;
1576   if (GCLockerEdenExpansionPercent > 0) {
1577     double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1578     double expansion_region_num_d = perc * (double) _young_list_target_length;
1579     // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1580     // less than 1.0) we'll get 1.
1581     expansion_region_num = (uint) ceil(expansion_region_num_d);
1582   } else {
1583     assert(expansion_region_num == 0, "sanity");
1584   }
1585   _young_list_max_length = _young_list_target_length + expansion_region_num;
1586   assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1587 }
1588 
1589 // Calculates survivor space parameters.
1590 void G1CollectorPolicy::update_survivors_policy() {
1591   double max_survivor_regions_d =
1592                  (double) _young_list_target_length / (double) SurvivorRatio;
1593   // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1594   // smaller than 1.0) we'll get 1.
1595   _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1596 
1597   _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1598         HeapRegion::GrainWords * _max_survivor_regions, counters());
1599 }
1600 
1601 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause) {
1602   // We actually check whether we are marking here and not if we are in a
1603   // reclamation phase. This means that we will schedule a concurrent mark
1604   // even while we are still in the process of reclaiming memory.
1605   bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1606   if (!during_cycle) {
1607     ergo_verbose1(ErgoConcCycles,
1608                   "request concurrent cycle initiation",
1609                   ergo_format_reason("requested by GC cause")
1610                   ergo_format_str("GC cause"),
1611                   GCCause::to_string(gc_cause));
1612     collector_state()->set_initiate_conc_mark_if_possible(true);
1613     return true;
1614   } else {
1615     ergo_verbose1(ErgoConcCycles,
1616                   "do not request concurrent cycle initiation",
1617                   ergo_format_reason("concurrent cycle already in progress")
1618                   ergo_format_str("GC cause"),
1619                   GCCause::to_string(gc_cause));
1620     return false;
1621   }
1622 }
1623 
1624 void G1CollectorPolicy::decide_on_conc_mark_initiation() {
1625   // We are about to decide on whether this pause will be an
1626   // initial-mark pause.
1627 
1628   // First, collector_state()->during_initial_mark_pause() should not be already set. We
1629   // will set it here if we have to. However, it should be cleared by
1630   // the end of the pause (it's only set for the duration of an
1631   // initial-mark pause).
1632   assert(!collector_state()->during_initial_mark_pause(), "pre-condition");
1633 
1634   if (collector_state()->initiate_conc_mark_if_possible()) {
1635     // We had noticed on a previous pause that the heap occupancy has
1636     // gone over the initiating threshold and we should start a
1637     // concurrent marking cycle. So we might initiate one.
1638 
1639     if (!about_to_start_mixed_phase() && collector_state()->gcs_are_young()) {
1640       // Initiate a new initial mark only if there is no marking or reclamation going
1641       // on.
1642 
1643       collector_state()->set_during_initial_mark_pause(true);
1644       // And we can now clear initiate_conc_mark_if_possible() as
1645       // we've already acted on it.
1646       collector_state()->set_initiate_conc_mark_if_possible(false);
1647 
1648       ergo_verbose0(ErgoConcCycles,
1649                   "initiate concurrent cycle",
1650                   ergo_format_reason("concurrent cycle initiation requested"));
1651     } else {
1652       // The concurrent marking thread is still finishing up the
1653       // previous cycle. If we start one right now the two cycles
1654       // overlap. In particular, the concurrent marking thread might
1655       // be in the process of clearing the next marking bitmap (which
1656       // we will use for the next cycle if we start one). Starting a
1657       // cycle now will be bad given that parts of the marking
1658       // information might get cleared by the marking thread. And we
1659       // cannot wait for the marking thread to finish the cycle as it
1660       // periodically yields while clearing the next marking bitmap
1661       // and, if it's in a yield point, it's waiting for us to
1662       // finish. So, at this point we will not start a cycle and we'll
1663       // let the concurrent marking thread complete the last one.
1664       ergo_verbose0(ErgoConcCycles,
1665                     "do not initiate concurrent cycle",
1666                     ergo_format_reason("concurrent cycle already in progress"));
1667     }
1668   }
1669 }
1670 
1671 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1672   G1CollectedHeap* _g1h;
1673   CSetChooserParUpdater _cset_updater;
1674 
1675 public:
1676   ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1677                            uint chunk_size) :
1678     _g1h(G1CollectedHeap::heap()),
1679     _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1680 
1681   bool doHeapRegion(HeapRegion* r) {
1682     // Do we have any marking information for this region?
1683     if (r->is_marked()) {
1684       // We will skip any region that's currently used as an old GC
1685       // alloc region (we should not consider those for collection
1686       // before we fill them up).
1687       if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1688         _cset_updater.add_region(r);
1689       }
1690     }
1691     return false;
1692   }
1693 };
1694 
1695 class ParKnownGarbageTask: public AbstractGangTask {
1696   CollectionSetChooser* _hrSorted;
1697   uint _chunk_size;
1698   G1CollectedHeap* _g1;
1699   HeapRegionClaimer _hrclaimer;
1700 
1701 public:
1702   ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
1703       AbstractGangTask("ParKnownGarbageTask"),
1704       _hrSorted(hrSorted), _chunk_size(chunk_size),
1705       _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
1706 
1707   void work(uint worker_id) {
1708     ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1709     _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
1710   }
1711 };
1712 
1713 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const {
1714   assert(n_workers > 0, "Active gc workers should be greater than 0");
1715   const uint overpartition_factor = 4;
1716   const uint min_chunk_size = MAX2(n_regions / n_workers, 1U);
1717   return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size);
1718 }
1719 
1720 void
1721 G1CollectorPolicy::record_concurrent_mark_cleanup_end() {
1722   _collectionSetChooser->clear();
1723 
1724   WorkGang* workers = _g1->workers();
1725   uint n_workers = workers->active_workers();
1726 
1727   uint n_regions = _g1->num_regions();
1728   uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions);
1729   _collectionSetChooser->prepare_for_par_region_addition(n_workers, n_regions, chunk_size);
1730   ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers);
1731   workers->run_task(&par_known_garbage_task);
1732 
1733   _collectionSetChooser->sort_regions();
1734 
1735   double end_sec = os::elapsedTime();
1736   double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1737   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1738   _cur_mark_stop_world_time_ms += elapsed_time_ms;
1739   _prev_collection_pause_end_ms += elapsed_time_ms;
1740   _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec);

1741 }
1742 
1743 // Add the heap region at the head of the non-incremental collection set
1744 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1745   assert(_inc_cset_build_state == Active, "Precondition");
1746   assert(hr->is_old(), "the region should be old");
1747 
1748   assert(!hr->in_collection_set(), "should not already be in the CSet");
1749   _g1->register_old_region_with_cset(hr);
1750   hr->set_next_in_collection_set(_collection_set);
1751   _collection_set = hr;
1752   _collection_set_bytes_used_before += hr->used();
1753   size_t rs_length = hr->rem_set()->occupied();
1754   _recorded_rs_lengths += rs_length;
1755   _old_cset_region_length += 1;
1756 }
1757 
1758 // Initialize the per-collection-set information
1759 void G1CollectorPolicy::start_incremental_cset_building() {
1760   assert(_inc_cset_build_state == Inactive, "Precondition");
1761 
1762   _inc_cset_head = NULL;
1763   _inc_cset_tail = NULL;
1764   _inc_cset_bytes_used_before = 0;
1765 
1766   _inc_cset_max_finger = 0;
1767   _inc_cset_recorded_rs_lengths = 0;
1768   _inc_cset_recorded_rs_lengths_diffs = 0;
1769   _inc_cset_predicted_elapsed_time_ms = 0.0;
1770   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1771   _inc_cset_build_state = Active;
1772 }
1773 
1774 void G1CollectorPolicy::finalize_incremental_cset_building() {
1775   assert(_inc_cset_build_state == Active, "Precondition");
1776   assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1777 
1778   // The two "main" fields, _inc_cset_recorded_rs_lengths and
1779   // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1780   // that adds a new region to the CSet. Further updates by the
1781   // concurrent refinement thread that samples the young RSet lengths
1782   // are accumulated in the *_diffs fields. Here we add the diffs to
1783   // the "main" fields.
1784 
1785   if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1786     _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1787   } else {
1788     // This is defensive. The diff should in theory be always positive
1789     // as RSets can only grow between GCs. However, given that we
1790     // sample their size concurrently with other threads updating them
1791     // it's possible that we might get the wrong size back, which
1792     // could make the calculations somewhat inaccurate.
1793     size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1794     if (_inc_cset_recorded_rs_lengths >= diffs) {
1795       _inc_cset_recorded_rs_lengths -= diffs;
1796     } else {
1797       _inc_cset_recorded_rs_lengths = 0;
1798     }
1799   }
1800   _inc_cset_predicted_elapsed_time_ms +=
1801                                      _inc_cset_predicted_elapsed_time_ms_diffs;
1802 
1803   _inc_cset_recorded_rs_lengths_diffs = 0;
1804   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1805 }
1806 
1807 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1808   // This routine is used when:
1809   // * adding survivor regions to the incremental cset at the end of an
1810   //   evacuation pause,
1811   // * adding the current allocation region to the incremental cset
1812   //   when it is retired, and
1813   // * updating existing policy information for a region in the
1814   //   incremental cset via young list RSet sampling.
1815   // Therefore this routine may be called at a safepoint by the
1816   // VM thread, or in-between safepoints by mutator threads (when
1817   // retiring the current allocation region) or a concurrent
1818   // refine thread (RSet sampling).
1819 
1820   double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1821   size_t used_bytes = hr->used();
1822   _inc_cset_recorded_rs_lengths += rs_length;
1823   _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1824   _inc_cset_bytes_used_before += used_bytes;
1825 
1826   // Cache the values we have added to the aggregated information
1827   // in the heap region in case we have to remove this region from
1828   // the incremental collection set, or it is updated by the
1829   // rset sampling code
1830   hr->set_recorded_rs_length(rs_length);
1831   hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1832 }
1833 
1834 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1835                                                      size_t new_rs_length) {
1836   // Update the CSet information that is dependent on the new RS length
1837   assert(hr->is_young(), "Precondition");
1838   assert(!SafepointSynchronize::is_at_safepoint(),
1839                                                "should not be at a safepoint");
1840 
1841   // We could have updated _inc_cset_recorded_rs_lengths and
1842   // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1843   // that atomically, as this code is executed by a concurrent
1844   // refinement thread, potentially concurrently with a mutator thread
1845   // allocating a new region and also updating the same fields. To
1846   // avoid the atomic operations we accumulate these updates on two
1847   // separate fields (*_diffs) and we'll just add them to the "main"
1848   // fields at the start of a GC.
1849 
1850   ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1851   ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1852   _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1853 
1854   double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1855   double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1856   double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1857   _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1858 
1859   hr->set_recorded_rs_length(new_rs_length);
1860   hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1861 }
1862 
1863 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1864   assert(hr->is_young(), "invariant");
1865   assert(hr->young_index_in_cset() > -1, "should have already been set");
1866   assert(_inc_cset_build_state == Active, "Precondition");
1867 
1868   // We need to clear and set the cached recorded/cached collection set
1869   // information in the heap region here (before the region gets added
1870   // to the collection set). An individual heap region's cached values
1871   // are calculated, aggregated with the policy collection set info,
1872   // and cached in the heap region here (initially) and (subsequently)
1873   // by the Young List sampling code.
1874 
1875   size_t rs_length = hr->rem_set()->occupied();
1876   add_to_incremental_cset_info(hr, rs_length);
1877 
1878   HeapWord* hr_end = hr->end();
1879   _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1880 
1881   assert(!hr->in_collection_set(), "invariant");
1882   _g1->register_young_region_with_cset(hr);
1883   assert(hr->next_in_collection_set() == NULL, "invariant");
1884 }
1885 
1886 // Add the region at the RHS of the incremental cset
1887 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1888   // We should only ever be appending survivors at the end of a pause
1889   assert(hr->is_survivor(), "Logic");
1890 
1891   // Do the 'common' stuff
1892   add_region_to_incremental_cset_common(hr);
1893 
1894   // Now add the region at the right hand side
1895   if (_inc_cset_tail == NULL) {
1896     assert(_inc_cset_head == NULL, "invariant");
1897     _inc_cset_head = hr;
1898   } else {
1899     _inc_cset_tail->set_next_in_collection_set(hr);
1900   }
1901   _inc_cset_tail = hr;
1902 }
1903 
1904 // Add the region to the LHS of the incremental cset
1905 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1906   // Survivors should be added to the RHS at the end of a pause
1907   assert(hr->is_eden(), "Logic");
1908 
1909   // Do the 'common' stuff
1910   add_region_to_incremental_cset_common(hr);
1911 
1912   // Add the region at the left hand side
1913   hr->set_next_in_collection_set(_inc_cset_head);
1914   if (_inc_cset_head == NULL) {
1915     assert(_inc_cset_tail == NULL, "Invariant");
1916     _inc_cset_tail = hr;
1917   }
1918   _inc_cset_head = hr;
1919 }
1920 
1921 #ifndef PRODUCT
1922 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1923   assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1924 
1925   st->print_cr("\nCollection_set:");
1926   HeapRegion* csr = list_head;
1927   while (csr != NULL) {
1928     HeapRegion* next = csr->next_in_collection_set();
1929     assert(csr->in_collection_set(), "bad CS");
1930     st->print_cr("  " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d",
1931                  HR_FORMAT_PARAMS(csr),
1932                  p2i(csr->prev_top_at_mark_start()), p2i(csr->next_top_at_mark_start()),
1933                  csr->age_in_surv_rate_group_cond());
1934     csr = next;
1935   }
1936 }
1937 #endif // !PRODUCT
1938 
1939 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) const {
1940   // Returns the given amount of reclaimable bytes (that represents
1941   // the amount of reclaimable space still to be collected) as a
1942   // percentage of the current heap capacity.
1943   size_t capacity_bytes = _g1->capacity();
1944   return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1945 }
1946 
1947 void G1CollectorPolicy::maybe_start_marking() {
1948   if (need_to_start_conc_mark("end of GC")) {
1949     // Note: this might have already been set, if during the last
1950     // pause we decided to start a cycle but at the beginning of
1951     // this pause we decided to postpone it. That's OK.
1952     collector_state()->set_initiate_conc_mark_if_possible(true);
1953   }





















































1954 }
1955 
1956 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1957                                                 const char* false_action_str) const {
1958   CollectionSetChooser* cset_chooser = _collectionSetChooser;
1959   if (cset_chooser->is_empty()) {
1960     ergo_verbose0(ErgoMixedGCs,
1961                   false_action_str,
1962                   ergo_format_reason("candidate old regions not available"));
1963     return false;
1964   }
1965 
1966   // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1967   size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1968   double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1969   double threshold = (double) G1HeapWastePercent;
1970   if (reclaimable_perc <= threshold) {
1971     ergo_verbose4(ErgoMixedGCs,
1972               false_action_str,
1973               ergo_format_reason("reclaimable percentage not over threshold")
1974               ergo_format_region("candidate old regions")
1975               ergo_format_byte_perc("reclaimable")
1976               ergo_format_perc("threshold"),
1977               cset_chooser->remaining_regions(),
1978               reclaimable_bytes,
1979               reclaimable_perc, threshold);
1980     return false;
1981   }
1982 
1983   ergo_verbose4(ErgoMixedGCs,
1984                 true_action_str,
1985                 ergo_format_reason("candidate old regions available")
1986                 ergo_format_region("candidate old regions")
1987                 ergo_format_byte_perc("reclaimable")
1988                 ergo_format_perc("threshold"),
1989                 cset_chooser->remaining_regions(),
1990                 reclaimable_bytes,
1991                 reclaimable_perc, threshold);
1992   return true;
1993 }
1994 
1995 uint G1CollectorPolicy::calc_min_old_cset_length() const {
1996   // The min old CSet region bound is based on the maximum desired
1997   // number of mixed GCs after a cycle. I.e., even if some old regions
1998   // look expensive, we should add them to the CSet anyway to make
1999   // sure we go through the available old regions in no more than the
2000   // maximum desired number of mixed GCs.
2001   //
2002   // The calculation is based on the number of marked regions we added
2003   // to the CSet chooser in the first place, not how many remain, so
2004   // that the result is the same during all mixed GCs that follow a cycle.
2005 
2006   const size_t region_num = (size_t) _collectionSetChooser->length();
2007   const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
2008   size_t result = region_num / gc_num;
2009   // emulate ceiling
2010   if (result * gc_num < region_num) {
2011     result += 1;
2012   }
2013   return (uint) result;
2014 }
2015 
2016 uint G1CollectorPolicy::calc_max_old_cset_length() const {
2017   // The max old CSet region bound is based on the threshold expressed
2018   // as a percentage of the heap size. I.e., it should bound the
2019   // number of old regions added to the CSet irrespective of how many
2020   // of them are available.
2021 
2022   const G1CollectedHeap* g1h = G1CollectedHeap::heap();
2023   const size_t region_num = g1h->num_regions();
2024   const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
2025   size_t result = region_num * perc / 100;
2026   // emulate ceiling
2027   if (100 * result < region_num * perc) {
2028     result += 1;
2029   }
2030   return (uint) result;
2031 }
2032 
2033 
2034 double G1CollectorPolicy::finalize_young_cset_part(double target_pause_time_ms) {
2035   double young_start_time_sec = os::elapsedTime();
2036 
2037   YoungList* young_list = _g1->young_list();
2038   finalize_incremental_cset_building();
2039 
2040   guarantee(target_pause_time_ms > 0.0,
2041             "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms);
2042   guarantee(_collection_set == NULL, "Precondition");
2043 
2044   double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2045   double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
2046 
2047   ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
2048                 "start choosing CSet",
2049                 ergo_format_size("_pending_cards")
2050                 ergo_format_ms("predicted base time")
2051                 ergo_format_ms("remaining time")
2052                 ergo_format_ms("target pause time"),
2053                 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
2054 
2055   collector_state()->set_last_gc_was_young(collector_state()->gcs_are_young());
2056 
2057   if (collector_state()->last_gc_was_young()) {
2058     _trace_young_gen_time_data.increment_young_collection_count();
2059   } else {
2060     _trace_young_gen_time_data.increment_mixed_collection_count();
2061   }
2062 
2063   // The young list is laid with the survivor regions from the previous
2064   // pause are appended to the RHS of the young list, i.e.
2065   //   [Newly Young Regions ++ Survivors from last pause].
2066 
2067   uint survivor_region_length = young_list->survivor_length();
2068   uint eden_region_length = young_list->eden_length();
2069   init_cset_region_lengths(eden_region_length, survivor_region_length);
2070 
2071   HeapRegion* hr = young_list->first_survivor_region();
2072   while (hr != NULL) {
2073     assert(hr->is_survivor(), "badly formed young list");
2074     // There is a convention that all the young regions in the CSet
2075     // are tagged as "eden", so we do this for the survivors here. We
2076     // use the special set_eden_pre_gc() as it doesn't check that the
2077     // region is free (which is not the case here).
2078     hr->set_eden_pre_gc();
2079     hr = hr->get_next_young_region();
2080   }
2081 
2082   // Clear the fields that point to the survivor list - they are all young now.
2083   young_list->clear_survivors();
2084 
2085   _collection_set = _inc_cset_head;
2086   _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2087   time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
2088 
2089   ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
2090                 "add young regions to CSet",
2091                 ergo_format_region("eden")
2092                 ergo_format_region("survivors")
2093                 ergo_format_ms("predicted young region time")
2094                 ergo_format_ms("target pause time"),
2095                 eden_region_length, survivor_region_length,
2096                 _inc_cset_predicted_elapsed_time_ms,
2097                 target_pause_time_ms);
2098 
2099   // The number of recorded young regions is the incremental
2100   // collection set's current size
2101   set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2102 
2103   double young_end_time_sec = os::elapsedTime();
2104   phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
2105 
2106   return time_remaining_ms;
2107 }
2108 
2109 void G1CollectorPolicy::finalize_old_cset_part(double time_remaining_ms) {
2110   double non_young_start_time_sec = os::elapsedTime();
2111   double predicted_old_time_ms = 0.0;
2112 
2113 
2114   if (!collector_state()->gcs_are_young()) {
2115     CollectionSetChooser* cset_chooser = _collectionSetChooser;
2116     cset_chooser->verify();
2117     const uint min_old_cset_length = calc_min_old_cset_length();
2118     const uint max_old_cset_length = calc_max_old_cset_length();
2119 
2120     uint expensive_region_num = 0;
2121     bool check_time_remaining = adaptive_young_list_length();
2122 
2123     HeapRegion* hr = cset_chooser->peek();
2124     while (hr != NULL) {
2125       if (old_cset_region_length() >= max_old_cset_length) {
2126         // Added maximum number of old regions to the CSet.
2127         ergo_verbose2(ErgoCSetConstruction,
2128                       "finish adding old regions to CSet",
2129                       ergo_format_reason("old CSet region num reached max")
2130                       ergo_format_region("old")
2131                       ergo_format_region("max"),
2132                       old_cset_region_length(), max_old_cset_length);
2133         break;
2134       }
2135 
2136 
2137       // Stop adding regions if the remaining reclaimable space is
2138       // not above G1HeapWastePercent.
2139       size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
2140       double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
2141       double threshold = (double) G1HeapWastePercent;
2142       if (reclaimable_perc <= threshold) {
2143         // We've added enough old regions that the amount of uncollected
2144         // reclaimable space is at or below the waste threshold. Stop
2145         // adding old regions to the CSet.
2146         ergo_verbose5(ErgoCSetConstruction,
2147                       "finish adding old regions to CSet",
2148                       ergo_format_reason("reclaimable percentage not over threshold")
2149                       ergo_format_region("old")
2150                       ergo_format_region("max")
2151                       ergo_format_byte_perc("reclaimable")
2152                       ergo_format_perc("threshold"),
2153                       old_cset_region_length(),
2154                       max_old_cset_length,
2155                       reclaimable_bytes,
2156                       reclaimable_perc, threshold);
2157         break;
2158       }
2159 
2160       double predicted_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
2161       if (check_time_remaining) {
2162         if (predicted_time_ms > time_remaining_ms) {
2163           // Too expensive for the current CSet.
2164 
2165           if (old_cset_region_length() >= min_old_cset_length) {
2166             // We have added the minimum number of old regions to the CSet,
2167             // we are done with this CSet.
2168             ergo_verbose4(ErgoCSetConstruction,
2169                           "finish adding old regions to CSet",
2170                           ergo_format_reason("predicted time is too high")
2171                           ergo_format_ms("predicted time")
2172                           ergo_format_ms("remaining time")
2173                           ergo_format_region("old")
2174                           ergo_format_region("min"),
2175                           predicted_time_ms, time_remaining_ms,
2176                           old_cset_region_length(), min_old_cset_length);
2177             break;
2178           }
2179 
2180           // We'll add it anyway given that we haven't reached the
2181           // minimum number of old regions.
2182           expensive_region_num += 1;
2183         }
2184       } else {
2185         if (old_cset_region_length() >= min_old_cset_length) {
2186           // In the non-auto-tuning case, we'll finish adding regions
2187           // to the CSet if we reach the minimum.
2188           ergo_verbose2(ErgoCSetConstruction,
2189                         "finish adding old regions to CSet",
2190                         ergo_format_reason("old CSet region num reached min")
2191                         ergo_format_region("old")
2192                         ergo_format_region("min"),
2193                         old_cset_region_length(), min_old_cset_length);
2194           break;
2195         }
2196       }
2197 
2198       // We will add this region to the CSet.
2199       time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2200       predicted_old_time_ms += predicted_time_ms;
2201       cset_chooser->pop(); // already have region via peek()
2202       _g1->old_set_remove(hr);
2203       add_old_region_to_cset(hr);
2204 
2205       hr = cset_chooser->peek();
2206     }
2207     if (hr == NULL) {
2208       ergo_verbose0(ErgoCSetConstruction,
2209                     "finish adding old regions to CSet",
2210                     ergo_format_reason("candidate old regions not available"));
2211     }
2212 
2213     if (expensive_region_num > 0) {
2214       // We print the information once here at the end, predicated on
2215       // whether we added any apparently expensive regions or not, to
2216       // avoid generating output per region.
2217       ergo_verbose4(ErgoCSetConstruction,
2218                     "added expensive regions to CSet",
2219                     ergo_format_reason("old CSet region num not reached min")
2220                     ergo_format_region("old")
2221                     ergo_format_region("expensive")
2222                     ergo_format_region("min")
2223                     ergo_format_ms("remaining time"),
2224                     old_cset_region_length(),
2225                     expensive_region_num,
2226                     min_old_cset_length,
2227                     time_remaining_ms);
2228     }
2229 
2230     cset_chooser->verify();
2231   }
2232 
2233   stop_incremental_cset_building();
2234 
2235   ergo_verbose3(ErgoCSetConstruction,
2236                 "finish choosing CSet",
2237                 ergo_format_region("old")
2238                 ergo_format_ms("predicted old region time")
2239                 ergo_format_ms("time remaining"),
2240                 old_cset_region_length(),
2241                 predicted_old_time_ms, time_remaining_ms);
2242 
2243   double non_young_end_time_sec = os::elapsedTime();
2244   phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2245 }
2246 
2247 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) {
2248   if(TraceYoungGenTime) {
2249     _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2250   }
2251 }
2252 
2253 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) {
2254   if(TraceYoungGenTime) {
2255     _all_yield_times_ms.add(yield_time_ms);
2256   }
2257 }
2258 
2259 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2260   if(TraceYoungGenTime) {
2261     _total.add(pause_time_ms);
2262     _other.add(pause_time_ms - phase_times->accounted_time_ms());
2263     _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2264     _parallel.add(phase_times->cur_collection_par_time_ms());
2265     _ext_root_scan.add(phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan));
2266     _satb_filtering.add(phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering));
2267     _update_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS));
2268     _scan_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::ScanRS));
2269     _obj_copy.add(phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy));
2270     _termination.add(phase_times->average_time_ms(G1GCPhaseTimes::Termination));
2271 
2272     double parallel_known_time = phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan) +
2273       phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering) +
2274       phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS) +
2275       phase_times->average_time_ms(G1GCPhaseTimes::ScanRS) +
2276       phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy) +
2277       phase_times->average_time_ms(G1GCPhaseTimes::Termination);
2278 
2279     double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2280     _parallel_other.add(parallel_other_time);
2281     _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2282   }
2283 }
2284 
2285 void TraceYoungGenTimeData::increment_young_collection_count() {
2286   if(TraceYoungGenTime) {
2287     ++_young_pause_num;
2288   }
2289 }
2290 
2291 void TraceYoungGenTimeData::increment_mixed_collection_count() {
2292   if(TraceYoungGenTime) {
2293     ++_mixed_pause_num;
2294   }
2295 }
2296 
2297 void TraceYoungGenTimeData::print_summary(const char* str,
2298                                           const NumberSeq* seq) const {
2299   double sum = seq->sum();
2300   gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2301                 str, sum / 1000.0, seq->avg());
2302 }
2303 
2304 void TraceYoungGenTimeData::print_summary_sd(const char* str,
2305                                              const NumberSeq* seq) const {
2306   print_summary(str, seq);
2307   gclog_or_tty->print_cr("%45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2308                 "(num", seq->num(), seq->sd(), seq->maximum());
2309 }
2310 
2311 void TraceYoungGenTimeData::print() const {
2312   if (!TraceYoungGenTime) {
2313     return;
2314   }
2315 
2316   gclog_or_tty->print_cr("ALL PAUSES");
2317   print_summary_sd("   Total", &_total);
2318   gclog_or_tty->cr();
2319   gclog_or_tty->cr();
2320   gclog_or_tty->print_cr("   Young GC Pauses: %8d", _young_pause_num);
2321   gclog_or_tty->print_cr("   Mixed GC Pauses: %8d", _mixed_pause_num);
2322   gclog_or_tty->cr();
2323 
2324   gclog_or_tty->print_cr("EVACUATION PAUSES");
2325 
2326   if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2327     gclog_or_tty->print_cr("none");
2328   } else {
2329     print_summary_sd("   Evacuation Pauses", &_total);
2330     print_summary("      Root Region Scan Wait", &_root_region_scan_wait);
2331     print_summary("      Parallel Time", &_parallel);
2332     print_summary("         Ext Root Scanning", &_ext_root_scan);
2333     print_summary("         SATB Filtering", &_satb_filtering);
2334     print_summary("         Update RS", &_update_rs);
2335     print_summary("         Scan RS", &_scan_rs);
2336     print_summary("         Object Copy", &_obj_copy);
2337     print_summary("         Termination", &_termination);
2338     print_summary("         Parallel Other", &_parallel_other);
2339     print_summary("      Clear CT", &_clear_ct);
2340     print_summary("      Other", &_other);
2341   }
2342   gclog_or_tty->cr();
2343 
2344   gclog_or_tty->print_cr("MISC");
2345   print_summary_sd("   Stop World", &_all_stop_world_times_ms);
2346   print_summary_sd("   Yields", &_all_yield_times_ms);
2347 }
2348 
2349 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) {
2350   if (TraceOldGenTime) {
2351     _all_full_gc_times.add(full_gc_time_ms);
2352   }
2353 }
2354 
2355 void TraceOldGenTimeData::print() const {
2356   if (!TraceOldGenTime) {
2357     return;
2358   }
2359 
2360   if (_all_full_gc_times.num() > 0) {
2361     gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2362       _all_full_gc_times.num(),
2363       _all_full_gc_times.sum() / 1000.0);
2364     gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2365     gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
2366       _all_full_gc_times.sd(),
2367       _all_full_gc_times.maximum());
2368   }
2369 }
--- EOF ---