rev 9277 : imported patch 8140597-forcing-initial-mark-causes-abort-mixed-collections
rev 9278 : imported patch 8139874-after-full-gc-next-gc-is-always-young-only
rev 9279 : imported patch 8138740-start-initial-mark-right-after-mixed-gc-if-needed
rev 9281 : imported patch 8140689-skip-last-young-if-nothing-to-do-in-mixed
rev 9282 : dihop-changes

   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   if ((2.0 /* magic */ * _predictor.sigma()) * bytes_to_copy > free_bytes) {
 471     // end condition 3: out-of-space (conservatively!)
 472     return false;
 473   }
 474 
 475   // success!
 476   return true;
 477 }
 478 
 479 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
 480   // re-calculate the necessary reserve
 481   double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
 482   // We use ceiling so that if reserve_regions_d is > 0.0 (but
 483   // smaller than 1.0) we'll get 1.
 484   _reserve_regions = (uint) ceil(reserve_regions_d);
 485 
 486   _young_gen_sizer->heap_size_changed(new_number_of_regions);
 487 }
 488 
 489 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
 490                                                        uint base_min_length) const {
 491   uint desired_min_length = 0;
 492   if (adaptive_young_list_length()) {
 493     if (_alloc_rate_ms_seq->num() > 3) {
 494       double now_sec = os::elapsedTime();
 495       double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
 496       double alloc_rate_ms = predict_alloc_rate_ms();
 497       desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
 498     } else {
 499       // otherwise we don't have enough info to make the prediction
 500     }
 501   }
 502   desired_min_length += base_min_length;
 503   // make sure we don't go below any user-defined minimum bound
 504   return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
 505 }
 506 
 507 uint G1CollectorPolicy::calculate_young_list_desired_max_length() const {
 508   // Here, we might want to also take into account any additional
 509   // constraints (i.e., user-defined minimum bound). Currently, we
 510   // effectively don't set this bound.
 511   return _young_gen_sizer->max_desired_young_length();
 512 }
 513 
 514 void G1CollectorPolicy::update_young_list_max_and_target_length() {
 515   update_young_list_max_and_target_length(get_new_prediction(_rs_lengths_seq));
 516 }
 517 
 518 void G1CollectorPolicy::update_young_list_max_and_target_length(size_t rs_lengths) {
 519   update_young_list_target_length(rs_lengths);
 520   update_max_gc_locker_expansion();
 521 }
 522 
 523 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
 524   _young_list_target_length = bounded_young_list_target_length(rs_lengths);
 525 }
 526 
 527 void G1CollectorPolicy::update_young_list_target_length() {
 528   update_young_list_target_length(get_new_prediction(_rs_lengths_seq));
 529 }
 530 
 531 uint G1CollectorPolicy::bounded_young_list_target_length(size_t rs_lengths) const {
 532   // Calculate the absolute and desired min bounds.
 533 
 534   // This is how many young regions we already have (currently: the survivors).
 535   uint base_min_length = recorded_survivor_regions();
 536   uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
 537   // This is the absolute minimum young length. Ensure that we
 538   // will at least have one eden region available for allocation.
 539   uint absolute_min_length = base_min_length + MAX2(_g1->young_list()->eden_length(), (uint)1);
 540   // If we shrank the young list target it should not shrink below the current size.
 541   desired_min_length = MAX2(desired_min_length, absolute_min_length);
 542   // Calculate the absolute and desired max bounds.
 543 
 544   // We will try our best not to "eat" into the reserve.
 545   uint absolute_max_length = 0;
 546   if (_free_regions_at_end_of_collection > _reserve_regions) {
 547     absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
 548   }
 549   uint desired_max_length = calculate_young_list_desired_max_length();
 550   if (desired_max_length > absolute_max_length) {
 551     desired_max_length = absolute_max_length;
 552   }
 553 
 554   uint young_list_target_length = 0;
 555   if (adaptive_young_list_length()) {
 556     if (collector_state()->gcs_are_young()) {
 557       young_list_target_length =
 558                         calculate_young_list_target_length(rs_lengths,
 559                                                            base_min_length,
 560                                                            desired_min_length,
 561                                                            desired_max_length);
 562     } else {
 563       // Don't calculate anything and let the code below bound it to
 564       // the desired_min_length, i.e., do the next GC as soon as
 565       // possible to maximize how many old regions we can add to it.
 566     }
 567   } else {
 568     // The user asked for a fixed young gen so we'll fix the young gen
 569     // whether the next GC is young or mixed.
 570     young_list_target_length = _young_list_fixed_length;
 571   }
 572 













 573   // Make sure we don't go over the desired max length, nor under the
 574   // desired min length. In case they clash, desired_min_length wins
 575   // which is why that test is second.
 576   if (young_list_target_length > desired_max_length) {
 577     young_list_target_length = desired_max_length;
 578   }
 579   if (young_list_target_length < desired_min_length) {
 580     young_list_target_length = desired_min_length;
 581   }
 582 
 583   assert(young_list_target_length > recorded_survivor_regions(),
 584          "we should be able to allocate at least one eden region");
 585   assert(young_list_target_length >= absolute_min_length, "post-condition");
 586 
 587   return young_list_target_length;
 588 }
 589 
 590 uint
 591 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
 592                                                      uint base_min_length,
 593                                                      uint desired_min_length,
 594                                                      uint desired_max_length) const {
 595   assert(adaptive_young_list_length(), "pre-condition");
 596   assert(collector_state()->gcs_are_young(), "only call this for young GCs");
 597 
 598   // In case some edge-condition makes the desired max length too small...
 599   if (desired_max_length <= desired_min_length) {
 600     return desired_min_length;
 601   }
 602 
 603   // We'll adjust min_young_length and max_young_length not to include
 604   // the already allocated young regions (i.e., so they reflect the
 605   // min and max eden regions we'll allocate). The base_min_length
 606   // will be reflected in the predictions by the
 607   // survivor_regions_evac_time prediction.
 608   assert(desired_min_length > base_min_length, "invariant");
 609   uint min_young_length = desired_min_length - base_min_length;
 610   assert(desired_max_length > base_min_length, "invariant");
 611   uint max_young_length = desired_max_length - base_min_length;
 612 
 613   double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
 614   double survivor_regions_evac_time = predict_survivor_regions_evac_time();
 615   size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
 616   size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
 617   size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
 618   double base_time_ms =
 619     predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
 620     survivor_regions_evac_time;
 621   uint available_free_regions = _free_regions_at_end_of_collection;
 622   uint base_free_regions = 0;
 623   if (available_free_regions > _reserve_regions) {
 624     base_free_regions = available_free_regions - _reserve_regions;
 625   }
 626 
 627   // Here, we will make sure that the shortest young length that
 628   // makes sense fits within the target pause time.
 629 
 630   if (predict_will_fit(min_young_length, base_time_ms,
 631                        base_free_regions, target_pause_time_ms)) {
 632     // The shortest young length will fit into the target pause time;
 633     // we'll now check whether the absolute maximum number of young
 634     // regions will fit in the target pause time. If not, we'll do
 635     // a binary search between min_young_length and max_young_length.
 636     if (predict_will_fit(max_young_length, base_time_ms,
 637                          base_free_regions, target_pause_time_ms)) {
 638       // The maximum young length will fit into the target pause time.
 639       // We are done so set min young length to the maximum length (as
 640       // the result is assumed to be returned in min_young_length).
 641       min_young_length = max_young_length;
 642     } else {
 643       // The maximum possible number of young regions will not fit within
 644       // the target pause time so we'll search for the optimal
 645       // length. The loop invariants are:
 646       //
 647       // min_young_length < max_young_length
 648       // min_young_length is known to fit into the target pause time
 649       // max_young_length is known not to fit into the target pause time
 650       //
 651       // Going into the loop we know the above hold as we've just
 652       // checked them. Every time around the loop we check whether
 653       // the middle value between min_young_length and
 654       // max_young_length fits into the target pause time. If it
 655       // does, it becomes the new min. If it doesn't, it becomes
 656       // the new max. This way we maintain the loop invariants.
 657 
 658       assert(min_young_length < max_young_length, "invariant");
 659       uint diff = (max_young_length - min_young_length) / 2;
 660       while (diff > 0) {
 661         uint young_length = min_young_length + diff;
 662         if (predict_will_fit(young_length, base_time_ms,
 663                              base_free_regions, target_pause_time_ms)) {
 664           min_young_length = young_length;
 665         } else {
 666           max_young_length = young_length;
 667         }
 668         assert(min_young_length <  max_young_length, "invariant");
 669         diff = (max_young_length - min_young_length) / 2;
 670       }
 671       // The results is min_young_length which, according to the
 672       // loop invariants, should fit within the target pause time.
 673 
 674       // These are the post-conditions of the binary search above:
 675       assert(min_young_length < max_young_length,
 676              "otherwise we should have discovered that max_young_length "
 677              "fits into the pause target and not done the binary search");
 678       assert(predict_will_fit(min_young_length, base_time_ms,
 679                               base_free_regions, target_pause_time_ms),
 680              "min_young_length, the result of the binary search, should "
 681              "fit into the pause target");
 682       assert(!predict_will_fit(min_young_length + 1, base_time_ms,
 683                                base_free_regions, target_pause_time_ms),
 684              "min_young_length, the result of the binary search, should be "
 685              "optimal, so no larger length should fit into the pause target");
 686     }
 687   } else {
 688     // Even the minimum length doesn't fit into the pause time
 689     // target, return it as the result nevertheless.
 690   }
 691   return base_min_length + min_young_length;
 692 }
 693 
 694 double G1CollectorPolicy::predict_survivor_regions_evac_time() const {
 695   double survivor_regions_evac_time = 0.0;
 696   for (HeapRegion * r = _recorded_survivor_head;
 697        r != NULL && r != _recorded_survivor_tail->get_next_young_region();
 698        r = r->get_next_young_region()) {
 699     survivor_regions_evac_time += predict_region_elapsed_time_ms(r, collector_state()->gcs_are_young());
 700   }
 701   return survivor_regions_evac_time;
 702 }
 703 
 704 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
 705   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
 706 
 707   size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
 708   if (rs_lengths > _rs_lengths_prediction) {
 709     // add 10% to avoid having to recalculate often
 710     size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
 711     update_rs_lengths_prediction(rs_lengths_prediction);
 712 
 713     update_young_list_max_and_target_length(rs_lengths_prediction);
 714   }
 715 }
 716 
 717 void G1CollectorPolicy::update_rs_lengths_prediction() {
 718   update_rs_lengths_prediction(get_new_prediction(_rs_lengths_seq));
 719 }
 720 
 721 void G1CollectorPolicy::update_rs_lengths_prediction(size_t prediction) {
 722   if (collector_state()->gcs_are_young() && adaptive_young_list_length()) {
 723     _rs_lengths_prediction = prediction;
 724   }
 725 }
 726 
 727 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
 728                                                bool is_tlab,
 729                                                bool* gc_overhead_limit_was_exceeded) {
 730   guarantee(false, "Not using this policy feature yet.");
 731   return NULL;
 732 }
 733 
 734 // This method controls how a collector handles one or more
 735 // of its generations being fully allocated.
 736 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
 737                                                        bool is_tlab) {
 738   guarantee(false, "Not using this policy feature yet.");
 739   return NULL;
 740 }
 741 
 742 
 743 #ifndef PRODUCT
 744 bool G1CollectorPolicy::verify_young_ages() {
 745   HeapRegion* head = _g1->young_list()->first_region();
 746   return
 747     verify_young_ages(head, _short_lived_surv_rate_group);
 748   // also call verify_young_ages on any additional surv rate groups
 749 }
 750 
 751 bool
 752 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
 753                                      SurvRateGroup *surv_rate_group) {
 754   guarantee( surv_rate_group != NULL, "pre-condition" );
 755 
 756   const char* name = surv_rate_group->name();
 757   bool ret = true;
 758   int prev_age = -1;
 759 
 760   for (HeapRegion* curr = head;
 761        curr != NULL;
 762        curr = curr->get_next_young_region()) {
 763     SurvRateGroup* group = curr->surv_rate_group();
 764     if (group == NULL && !curr->is_survivor()) {
 765       gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
 766       ret = false;
 767     }
 768 
 769     if (surv_rate_group == group) {
 770       int age = curr->age_in_surv_rate_group();
 771 
 772       if (age < 0) {
 773         gclog_or_tty->print_cr("## %s: encountered negative age", name);
 774         ret = false;
 775       }
 776 
 777       if (age <= prev_age) {
 778         gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
 779                                "(%d, %d)", name, age, prev_age);
 780         ret = false;
 781       }
 782       prev_age = age;
 783     }
 784   }
 785 
 786   return ret;
 787 }
 788 #endif // PRODUCT
 789 
 790 void G1CollectorPolicy::record_full_collection_start() {
 791   _full_collection_start_sec = os::elapsedTime();
 792   record_heap_size_info_at_start(true /* full */);
 793   // Release the future to-space so that it is available for compaction into.
 794   collector_state()->set_full_collection(true);
 795 }
 796 
 797 void G1CollectorPolicy::record_full_collection_end() {
 798   // Consider this like a collection pause for the purposes of allocation
 799   // since last pause.
 800   double end_sec = os::elapsedTime();
 801   double full_gc_time_sec = end_sec - _full_collection_start_sec;
 802   double full_gc_time_ms = full_gc_time_sec * 1000.0;
 803 
 804   _trace_old_gen_time_data.record_full_collection(full_gc_time_ms);
 805 
 806   update_recent_gc_times(end_sec, full_gc_time_ms);
 807 
 808   collector_state()->set_full_collection(false);
 809 
 810   // "Nuke" the heuristics that control the young/mixed GC
 811   // transitions and make sure we start with young GCs after the Full GC.
 812   collector_state()->set_gcs_are_young(true);
 813   collector_state()->set_last_young_gc(false);
 814   collector_state()->set_initiate_conc_mark_if_possible(need_to_start_conc_mark("end of Full GC", 0));
 815   collector_state()->set_during_initial_mark_pause(false);
 816   collector_state()->set_in_marking_window(false);
 817   collector_state()->set_in_marking_window_im(false);
 818 
 819   _short_lived_surv_rate_group->start_adding_regions();
 820   // also call this on any additional surv rate groups
 821 
 822   record_survivor_regions(0, NULL, NULL);
 823 
 824   _free_regions_at_end_of_collection = _g1->num_free_regions();
 825   // Reset survivors SurvRateGroup.
 826   _survivor_surv_rate_group->reset();
 827   update_young_list_max_and_target_length();
 828   update_rs_lengths_prediction();
 829   _collectionSetChooser->clear();




 830 }
 831 
 832 void G1CollectorPolicy::record_stop_world_start() {
 833   _stop_world_start = os::elapsedTime();
 834 }
 835 
 836 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
 837   // We only need to do this here as the policy will only be applied
 838   // to the GC we're about to start. so, no point is calculating this
 839   // every time we calculate / recalculate the target young length.
 840   update_survivors_policy();
 841 
 842   assert(_g1->used() == _g1->recalculate_used(),
 843          "sanity, used: " SIZE_FORMAT " recalculate_used: " SIZE_FORMAT,
 844          _g1->used(), _g1->recalculate_used());
 845 
 846   double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
 847   _trace_young_gen_time_data.record_start_collection(s_w_t_ms);
 848   _stop_world_start = 0.0;
 849 
 850   record_heap_size_info_at_start(false /* full */);
 851 
 852   phase_times()->record_cur_collection_start_sec(start_time_sec);
 853   _pending_cards = _g1->pending_card_num();
 854 
 855   _collection_set_bytes_used_before = 0;
 856   _bytes_copied_during_gc = 0;
 857 
 858   collector_state()->set_last_gc_was_young(false);
 859 
 860   // do that for any other surv rate groups
 861   _short_lived_surv_rate_group->stop_adding_regions();
 862   _survivors_age_table.clear();
 863 
 864   assert( verify_young_ages(), "region age verification" );
 865 }
 866 
 867 void G1CollectorPolicy::record_concurrent_mark_init_end(double
 868                                                    mark_init_elapsed_time_ms) {
 869   collector_state()->set_during_marking(true);
 870   assert(!collector_state()->initiate_conc_mark_if_possible(), "we should have cleared it by now");
 871   collector_state()->set_during_initial_mark_pause(false);
 872   _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
 873 }
 874 
 875 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
 876   _mark_remark_start_sec = os::elapsedTime();
 877   collector_state()->set_during_marking(false);
 878 }
 879 
 880 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
 881   double end_time_sec = os::elapsedTime();
 882   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
 883   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
 884   _cur_mark_stop_world_time_ms += elapsed_time_ms;
 885   _prev_collection_pause_end_ms += elapsed_time_ms;
 886 
 887   _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec);
 888 }
 889 
 890 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
 891   _mark_cleanup_start_sec = os::elapsedTime();
 892 }
 893 
 894 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
 895   bool should_continue_with_reclaim = next_gc_should_be_mixed("request last young-only gc",
 896                                                               "skip last young-only gc");
 897   collector_state()->set_last_young_gc(should_continue_with_reclaim);




 898   collector_state()->set_in_marking_window(false);
 899 }
 900 
 901 void G1CollectorPolicy::record_concurrent_pause() {
 902   if (_stop_world_start > 0.0) {
 903     double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
 904     _trace_young_gen_time_data.record_yield_time(yield_ms);
 905   }
 906 }
 907 
 908 double G1CollectorPolicy::average_time_ms(G1GCPhaseTimes::GCParPhases phase) const {
 909   return phase_times()->average_time_ms(phase);
 910 }
 911 
 912 double G1CollectorPolicy::young_other_time_ms() const {
 913   return phase_times()->young_cset_choice_time_ms() +
 914          phase_times()->young_free_cset_time_ms();
 915 }
 916 
 917 double G1CollectorPolicy::non_young_other_time_ms() const {
 918   return phase_times()->non_young_cset_choice_time_ms() +
 919          phase_times()->non_young_free_cset_time_ms();
 920 
 921 }
 922 
 923 double G1CollectorPolicy::other_time_ms(double pause_time_ms) const {
 924   return pause_time_ms -
 925          average_time_ms(G1GCPhaseTimes::UpdateRS) -
 926          average_time_ms(G1GCPhaseTimes::ScanRS) -
 927          average_time_ms(G1GCPhaseTimes::ObjCopy) -
 928          average_time_ms(G1GCPhaseTimes::Termination);
 929 }
 930 
 931 double G1CollectorPolicy::constant_other_time_ms(double pause_time_ms) const {
 932   return other_time_ms(pause_time_ms) - young_other_time_ms() - non_young_other_time_ms();
 933 }
 934 
 935 bool G1CollectorPolicy::about_to_start_mixed_phase() const {
 936   return _g1->concurrent_mark()->cmThread()->during_cycle() || collector_state()->last_young_gc();
 937 }
 938 
 939 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
 940   if (about_to_start_mixed_phase()) {
 941     return false;
 942   }
 943 
 944   size_t marking_initiating_used_threshold =
 945     (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
 946   size_t cur_used_bytes = _g1->non_young_capacity_bytes();
 947   size_t alloc_byte_size = alloc_word_size * HeapWordSize;

 948 
 949   if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
 950     if (collector_state()->gcs_are_young() && !collector_state()->last_young_gc()) {
 951       ergo_verbose5(ErgoConcCycles,
 952         "request concurrent cycle initiation",
 953         ergo_format_reason("occupancy higher than threshold")
 954         ergo_format_byte("occupancy")
 955         ergo_format_byte("allocation request")
 956         ergo_format_byte_perc("threshold")
 957         ergo_format_str("source"),
 958         cur_used_bytes,
 959         alloc_byte_size,
 960         marking_initiating_used_threshold,
 961         (double) InitiatingHeapOccupancyPercent,
 962         source);
 963       return true;
 964     } else {
 965       ergo_verbose5(ErgoConcCycles,
 966         "do not request concurrent cycle initiation",
 967         ergo_format_reason("still doing mixed collections")
 968         ergo_format_byte("occupancy")
 969         ergo_format_byte("allocation request")
 970         ergo_format_byte_perc("threshold")
 971         ergo_format_str("source"),
 972         cur_used_bytes,
 973         alloc_byte_size,
 974         marking_initiating_used_threshold,
 975         (double) InitiatingHeapOccupancyPercent,
 976         source);
 977     }
 978   }
 979 
 980   return false;
 981 }
 982 
 983 // Anything below that is considered to be zero
 984 #define MIN_TIMER_GRANULARITY 0.0000001
 985 
 986 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, size_t cards_scanned) {
 987   double end_time_sec = os::elapsedTime();
 988   assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
 989          "otherwise, the subtraction below does not make sense");
 990   size_t rs_size =
 991             _cur_collection_pause_used_regions_at_start - cset_region_length();
 992   size_t cur_used_bytes = _g1->used();
 993   assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
 994   bool last_pause_included_initial_mark = false;
 995   bool update_stats = !_g1->evacuation_failed();
 996 
 997 #ifndef PRODUCT
 998   if (G1YoungSurvRateVerbose) {
 999     gclog_or_tty->cr();
1000     _short_lived_surv_rate_group->print();
1001     // do that for any other surv rate groups too
1002   }
1003 #endif // PRODUCT
1004 


1005   last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
1006   if (last_pause_included_initial_mark) {
1007     record_concurrent_mark_init_end(0.0);
1008   } else {
1009     maybe_start_marking();
1010   }
1011 
1012   _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0, end_time_sec);
1013 
1014   if (update_stats) {
1015     _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times());
1016     // this is where we update the allocation rate of the application
1017     double app_time_ms =
1018       (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
1019     if (app_time_ms < MIN_TIMER_GRANULARITY) {
1020       // This usually happens due to the timer not having the required
1021       // granularity. Some Linuxes are the usual culprits.
1022       // We'll just set it to something (arbitrarily) small.
1023       app_time_ms = 1.0;
1024     }
1025     // We maintain the invariant that all objects allocated by mutator
1026     // threads will be allocated out of eden regions. So, we can use
1027     // the eden region number allocated since the previous GC to
1028     // calculate the application's allocate rate. The only exception
1029     // to that is humongous objects that are allocated separately. But
1030     // given that humongous object allocations do not really affect
1031     // either the pause's duration nor when the next pause will take
1032     // place we can safely ignore them here.
1033     uint regions_allocated = eden_cset_region_length();
1034     double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1035     _alloc_rate_ms_seq->add(alloc_rate_ms);
1036 
1037     double interval_ms =
1038       (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1039     update_recent_gc_times(end_time_sec, pause_time_ms);
1040     _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1041     if (recent_avg_pause_time_ratio() < 0.0 ||
1042         (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1043 #ifndef PRODUCT
1044       // Dump info to allow post-facto debugging
1045       gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1046       gclog_or_tty->print_cr("-------------------------------------------");
1047       gclog_or_tty->print_cr("Recent GC Times (ms):");
1048       _recent_gc_times_ms->dump();
1049       gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1050       _recent_prev_end_times_for_all_gcs_sec->dump();
1051       gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1052                              _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1053       // In debug mode, terminate the JVM if the user wants to debug at this point.
1054       assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1055 #endif  // !PRODUCT
1056       // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1057       // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1058       if (_recent_avg_pause_time_ratio < 0.0) {
1059         _recent_avg_pause_time_ratio = 0.0;
1060       } else {
1061         assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1062         _recent_avg_pause_time_ratio = 1.0;
1063       }
1064     }
1065   }
1066 
1067   bool new_in_marking_window = collector_state()->in_marking_window();
1068   bool new_in_marking_window_im = false;
1069   if (last_pause_included_initial_mark) {
1070     new_in_marking_window = true;
1071     new_in_marking_window_im = true;
1072   }
1073 
1074   if (collector_state()->last_young_gc()) {
1075     // This is supposed to to be the "last young GC" before we start
1076     // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1077     assert(!last_pause_included_initial_mark, "The last young GC is not allowed to be an initial mark GC");
1078 
1079     if (next_gc_should_be_mixed("start mixed GCs",
1080                                 "do not start mixed GCs")) {
1081       collector_state()->set_gcs_are_young(false);



1082     }
1083 
1084     collector_state()->set_last_young_gc(false);
1085   }
1086 
1087   if (!collector_state()->last_gc_was_young()) {
1088     // This is a mixed GC. Here we decide whether to continue doing
1089     // mixed GCs or not.
1090 
1091     if (!next_gc_should_be_mixed("continue mixed GCs",
1092                                  "do not continue mixed GCs")) {
1093       collector_state()->set_gcs_are_young(true);
1094 
1095       maybe_start_marking();
1096     }
1097   }
1098 
1099   _short_lived_surv_rate_group->start_adding_regions();
1100   // Do that for any other surv rate groups
1101 
1102   if (update_stats) {
1103     double cost_per_card_ms = 0.0;
1104     double cost_scan_hcc = average_time_ms(G1GCPhaseTimes::ScanHCC);
1105     if (_pending_cards > 0) {
1106       cost_per_card_ms = (average_time_ms(G1GCPhaseTimes::UpdateRS) - cost_scan_hcc) / (double) _pending_cards;
1107       _cost_per_card_ms_seq->add(cost_per_card_ms);
1108     }
1109     _cost_scan_hcc_seq->add(cost_scan_hcc);
1110 
1111     double cost_per_entry_ms = 0.0;
1112     if (cards_scanned > 10) {
1113       cost_per_entry_ms = average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
1114       if (collector_state()->last_gc_was_young()) {
1115         _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1116       } else {
1117         _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1118       }
1119     }
1120 
1121     if (_max_rs_lengths > 0) {
1122       double cards_per_entry_ratio =
1123         (double) cards_scanned / (double) _max_rs_lengths;
1124       if (collector_state()->last_gc_was_young()) {
1125         _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1126       } else {
1127         _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1128       }
1129     }
1130 
1131     // This is defensive. For a while _max_rs_lengths could get
1132     // smaller than _recorded_rs_lengths which was causing
1133     // rs_length_diff to get very large and mess up the RSet length
1134     // predictions. The reason was unsafe concurrent updates to the
1135     // _inc_cset_recorded_rs_lengths field which the code below guards
1136     // against (see CR 7118202). This bug has now been fixed (see CR
1137     // 7119027). However, I'm still worried that
1138     // _inc_cset_recorded_rs_lengths might still end up somewhat
1139     // inaccurate. The concurrent refinement thread calculates an
1140     // RSet's length concurrently with other CR threads updating it
1141     // which might cause it to calculate the length incorrectly (if,
1142     // say, it's in mid-coarsening). So I'll leave in the defensive
1143     // conditional below just in case.
1144     size_t rs_length_diff = 0;
1145     if (_max_rs_lengths > _recorded_rs_lengths) {
1146       rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1147     }
1148     _rs_length_diff_seq->add((double) rs_length_diff);
1149 
1150     size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1151     size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1152     double cost_per_byte_ms = 0.0;
1153 
1154     if (copied_bytes > 0) {
1155       cost_per_byte_ms = average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
1156       if (collector_state()->in_marking_window()) {
1157         _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1158       } else {
1159         _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1160       }
1161     }
1162 
1163     if (young_cset_region_length() > 0) {
1164       _young_other_cost_per_region_ms_seq->add(young_other_time_ms() /
1165                                                young_cset_region_length());
1166     }
1167 
1168     if (old_cset_region_length() > 0) {
1169       _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms() /
1170                                                    old_cset_region_length());
1171     }
1172 
1173     _constant_other_time_ms_seq->add(constant_other_time_ms(pause_time_ms));
1174 
1175     _pending_cards_seq->add((double) _pending_cards);
1176     _rs_lengths_seq->add((double) _max_rs_lengths);
1177   }
1178 
1179   collector_state()->set_in_marking_window(new_in_marking_window);
1180   collector_state()->set_in_marking_window_im(new_in_marking_window_im);
1181   _free_regions_at_end_of_collection = _g1->num_free_regions();
1182   update_young_list_max_and_target_length();





1183   update_rs_lengths_prediction();
1184 
















1185   // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1186   double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1187 
1188   double scan_hcc_time_ms = average_time_ms(G1GCPhaseTimes::ScanHCC);
1189 
1190   if (update_rs_time_goal_ms < scan_hcc_time_ms) {
1191     ergo_verbose2(ErgoTiming,
1192                   "adjust concurrent refinement thresholds",
1193                   ergo_format_reason("Scanning the HCC expected to take longer than Update RS time goal")
1194                   ergo_format_ms("Update RS time goal")
1195                   ergo_format_ms("Scan HCC time"),
1196                   update_rs_time_goal_ms,
1197                   scan_hcc_time_ms);
1198 
1199     update_rs_time_goal_ms = 0;
1200   } else {
1201     update_rs_time_goal_ms -= scan_hcc_time_ms;
1202   }
1203   adjust_concurrent_refinement(average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms,
1204                                phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS),
1205                                update_rs_time_goal_ms);
1206 
1207   _collectionSetChooser->verify();
1208 }
1209 






































1210 #define EXT_SIZE_FORMAT "%.1f%s"
1211 #define EXT_SIZE_PARAMS(bytes)                                  \
1212   byte_size_in_proper_unit((double)(bytes)),                    \
1213   proper_unit_for_byte_size((bytes))
1214 
1215 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1216   YoungList* young_list = _g1->young_list();
1217   _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1218   _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1219   _heap_capacity_bytes_before_gc = _g1->capacity();
1220   _heap_used_bytes_before_gc = _g1->used();
1221   _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1222 
1223   _eden_capacity_bytes_before_gc =
1224          (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1225 
1226   if (full) {
1227     _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1228   }
1229 }
1230 
1231 void G1CollectorPolicy::print_heap_transition(size_t bytes_before) const {
1232   size_t bytes_after = _g1->used();
1233   size_t capacity = _g1->capacity();
1234 
1235   gclog_or_tty->print(" " SIZE_FORMAT "%s->" SIZE_FORMAT "%s(" SIZE_FORMAT "%s)",
1236       byte_size_in_proper_unit(bytes_before),
1237       proper_unit_for_byte_size(bytes_before),
1238       byte_size_in_proper_unit(bytes_after),
1239       proper_unit_for_byte_size(bytes_after),
1240       byte_size_in_proper_unit(capacity),
1241       proper_unit_for_byte_size(capacity));
1242 }
1243 
1244 void G1CollectorPolicy::print_heap_transition() const {
1245   print_heap_transition(_heap_used_bytes_before_gc);
1246 }
1247 
1248 void G1CollectorPolicy::print_detailed_heap_transition(bool full) const {
1249   YoungList* young_list = _g1->young_list();
1250 
1251   size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1252   size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1253   size_t heap_used_bytes_after_gc = _g1->used();
1254 
1255   size_t heap_capacity_bytes_after_gc = _g1->capacity();
1256   size_t eden_capacity_bytes_after_gc =
1257     (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1258 
1259   gclog_or_tty->print(
1260     "   [Eden: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->" EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ") "
1261     "Survivors: " EXT_SIZE_FORMAT "->" EXT_SIZE_FORMAT " "
1262     "Heap: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->"
1263     EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")]",
1264     EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1265     EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1266     EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1267     EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1268     EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1269     EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1270     EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1271     EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1272     EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1273     EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1274 
1275   if (full) {
1276     MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1277   }
1278 
1279   gclog_or_tty->cr();
1280 }
1281 
1282 void G1CollectorPolicy::print_phases(double pause_time_sec) {
1283   phase_times()->print(pause_time_sec);
1284 }
1285 
1286 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1287                                                      double update_rs_processed_buffers,
1288                                                      double goal_ms) {
1289   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1290   ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1291 
1292   if (G1UseAdaptiveConcRefinement) {
1293     const int k_gy = 3, k_gr = 6;
1294     const double inc_k = 1.1, dec_k = 0.9;
1295 
1296     int g = cg1r->green_zone();
1297     if (update_rs_time > goal_ms) {
1298       g = (int)(g * dec_k);  // Can become 0, that's OK. That would mean a mutator-only processing.
1299     } else {
1300       if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1301         g = (int)MAX2(g * inc_k, g + 1.0);
1302       }
1303     }
1304     // Change the refinement threads params
1305     cg1r->set_green_zone(g);
1306     cg1r->set_yellow_zone(g * k_gy);
1307     cg1r->set_red_zone(g * k_gr);
1308     cg1r->reinitialize_threads();
1309 
1310     int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * _predictor.sigma()), 1);
1311     int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1312                                     cg1r->yellow_zone());
1313     // Change the barrier params
1314     dcqs.set_process_completed_threshold(processing_threshold);
1315     dcqs.set_max_completed_queue(cg1r->red_zone());
1316   }
1317 
1318   int curr_queue_size = dcqs.completed_buffers_num();
1319   if (curr_queue_size >= cg1r->yellow_zone()) {
1320     dcqs.set_completed_queue_padding(curr_queue_size);
1321   } else {
1322     dcqs.set_completed_queue_padding(0);
1323   }
1324   dcqs.notify_if_necessary();
1325 }
1326 
1327 size_t G1CollectorPolicy::predict_rs_length_diff() const {
1328   return (size_t) get_new_prediction(_rs_length_diff_seq);
1329 }
1330 
1331 double G1CollectorPolicy::predict_alloc_rate_ms() const {
1332   return get_new_prediction(_alloc_rate_ms_seq);
1333 }
1334 
1335 double G1CollectorPolicy::predict_cost_per_card_ms() const {
1336   return get_new_prediction(_cost_per_card_ms_seq);
1337 }
1338 
1339 double G1CollectorPolicy::predict_scan_hcc_ms() const {
1340   return get_new_prediction(_cost_scan_hcc_seq);
1341 }
1342 
1343 double G1CollectorPolicy::predict_rs_update_time_ms(size_t pending_cards) const {
1344   return pending_cards * predict_cost_per_card_ms() + predict_scan_hcc_ms();
1345 }
1346 
1347 double G1CollectorPolicy::predict_young_cards_per_entry_ratio() const {
1348   return get_new_prediction(_young_cards_per_entry_ratio_seq);
1349 }
1350 
1351 double G1CollectorPolicy::predict_mixed_cards_per_entry_ratio() const {
1352   if (_mixed_cards_per_entry_ratio_seq->num() < 2) {
1353     return predict_young_cards_per_entry_ratio();
1354   } else {
1355     return get_new_prediction(_mixed_cards_per_entry_ratio_seq);
1356   }
1357 }
1358 
1359 size_t G1CollectorPolicy::predict_young_card_num(size_t rs_length) const {
1360   return (size_t) (rs_length * predict_young_cards_per_entry_ratio());
1361 }
1362 
1363 size_t G1CollectorPolicy::predict_non_young_card_num(size_t rs_length) const {
1364   return (size_t)(rs_length * predict_mixed_cards_per_entry_ratio());
1365 }
1366 
1367 double G1CollectorPolicy::predict_rs_scan_time_ms(size_t card_num) const {
1368   if (collector_state()->gcs_are_young()) {
1369     return card_num * get_new_prediction(_cost_per_entry_ms_seq);
1370   } else {
1371     return predict_mixed_rs_scan_time_ms(card_num);
1372   }
1373 }
1374 
1375 double G1CollectorPolicy::predict_mixed_rs_scan_time_ms(size_t card_num) const {
1376   if (_mixed_cost_per_entry_ms_seq->num() < 3) {
1377     return card_num * get_new_prediction(_cost_per_entry_ms_seq);
1378   } else {
1379     return card_num * get_new_prediction(_mixed_cost_per_entry_ms_seq);
1380   }
1381 }
1382 
1383 double G1CollectorPolicy::predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const {
1384   if (_cost_per_byte_ms_during_cm_seq->num() < 3) {
1385     return (1.1 * bytes_to_copy) * get_new_prediction(_cost_per_byte_ms_seq);
1386   } else {
1387     return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_during_cm_seq);
1388   }
1389 }
1390 
1391 double G1CollectorPolicy::predict_object_copy_time_ms(size_t bytes_to_copy) const {
1392   if (collector_state()->during_concurrent_mark()) {
1393     return predict_object_copy_time_ms_during_cm(bytes_to_copy);
1394   } else {
1395     return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_seq);
1396   }
1397 }
1398 
1399 double G1CollectorPolicy::predict_constant_other_time_ms() const {
1400   return get_new_prediction(_constant_other_time_ms_seq);
1401 }
1402 
1403 double G1CollectorPolicy::predict_young_other_time_ms(size_t young_num) const {
1404   return young_num * get_new_prediction(_young_other_cost_per_region_ms_seq);
1405 }
1406 
1407 double G1CollectorPolicy::predict_non_young_other_time_ms(size_t non_young_num) const {
1408   return non_young_num * get_new_prediction(_non_young_other_cost_per_region_ms_seq);
1409 }
1410 
1411 double G1CollectorPolicy::predict_remark_time_ms() const {
1412   return get_new_prediction(_concurrent_mark_remark_times_ms);
1413 }
1414 
1415 double G1CollectorPolicy::predict_cleanup_time_ms() const {
1416   return get_new_prediction(_concurrent_mark_cleanup_times_ms);
1417 }
1418 
1419 double G1CollectorPolicy::predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const {
1420   TruncatedSeq* seq = surv_rate_group->get_seq(age);
1421   guarantee(seq->num() > 0, "There should be some young gen survivor samples available. Tried to access with age %d", age);
1422   double pred = get_new_prediction(seq);
1423   if (pred > 1.0) {
1424     pred = 1.0;
1425   }
1426   return pred;
1427 }
1428 
1429 double G1CollectorPolicy::predict_yg_surv_rate(int age) const {
1430   return predict_yg_surv_rate(age, _short_lived_surv_rate_group);
1431 }
1432 
1433 double G1CollectorPolicy::accum_yg_surv_rate_pred(int age) const {
1434   return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
1435 }
1436 
1437 double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1438                                                        size_t scanned_cards) const {
1439   return
1440     predict_rs_update_time_ms(pending_cards) +
1441     predict_rs_scan_time_ms(scanned_cards) +
1442     predict_constant_other_time_ms();
1443 }
1444 
1445 double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) const {
1446   size_t rs_length = predict_rs_length_diff();
1447   size_t card_num;
1448   if (collector_state()->gcs_are_young()) {
1449     card_num = predict_young_card_num(rs_length);
1450   } else {
1451     card_num = predict_non_young_card_num(rs_length);
1452   }
1453   return predict_base_elapsed_time_ms(pending_cards, card_num);
1454 }
1455 
1456 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) const {
1457   size_t bytes_to_copy;
1458   if (hr->is_marked())
1459     bytes_to_copy = hr->max_live_bytes();
1460   else {
1461     assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1462     int age = hr->age_in_surv_rate_group();
1463     double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1464     bytes_to_copy = (size_t) (hr->used() * yg_surv_rate);
1465   }
1466   return bytes_to_copy;
1467 }
1468 
1469 double G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1470                                                          bool for_young_gc) const {
1471   size_t rs_length = hr->rem_set()->occupied();
1472   size_t card_num;
1473 
1474   // Predicting the number of cards is based on which type of GC
1475   // we're predicting for.
1476   if (for_young_gc) {
1477     card_num = predict_young_card_num(rs_length);
1478   } else {
1479     card_num = predict_non_young_card_num(rs_length);
1480   }
1481   size_t bytes_to_copy = predict_bytes_to_copy(hr);
1482 
1483   double region_elapsed_time_ms =
1484     predict_rs_scan_time_ms(card_num) +
1485     predict_object_copy_time_ms(bytes_to_copy);
1486 
1487   // The prediction of the "other" time for this region is based
1488   // upon the region type and NOT the GC type.
1489   if (hr->is_young()) {
1490     region_elapsed_time_ms += predict_young_other_time_ms(1);
1491   } else {
1492     region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1493   }
1494   return region_elapsed_time_ms;
1495 }
1496 
1497 void G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1498                                                  uint survivor_cset_region_length) {
1499   _eden_cset_region_length     = eden_cset_region_length;
1500   _survivor_cset_region_length = survivor_cset_region_length;
1501   _old_cset_region_length      = 0;
1502 }
1503 
1504 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1505   _recorded_rs_lengths = rs_lengths;
1506 }
1507 
1508 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1509                                                double elapsed_ms) {
1510   _recent_gc_times_ms->add(elapsed_ms);
1511   _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1512   _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1513 }
1514 
1515 size_t G1CollectorPolicy::expansion_amount() const {
1516   double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1517   double threshold = _gc_overhead_perc;
1518   if (recent_gc_overhead > threshold) {
1519     // We will double the existing space, or take
1520     // G1ExpandByPercentOfAvailable % of the available expansion
1521     // space, whichever is smaller, bounded below by a minimum
1522     // expansion (unless that's all that's left.)
1523     const size_t min_expand_bytes = 1*M;
1524     size_t reserved_bytes = _g1->max_capacity();
1525     size_t committed_bytes = _g1->capacity();
1526     size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1527     size_t expand_bytes;
1528     size_t expand_bytes_via_pct =
1529       uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1530     expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1531     expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1532     expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1533 
1534     ergo_verbose5(ErgoHeapSizing,
1535                   "attempt heap expansion",
1536                   ergo_format_reason("recent GC overhead higher than "
1537                                      "threshold after GC")
1538                   ergo_format_perc("recent GC overhead")
1539                   ergo_format_perc("threshold")
1540                   ergo_format_byte("uncommitted")
1541                   ergo_format_byte_perc("calculated expansion amount"),
1542                   recent_gc_overhead, threshold,
1543                   uncommitted_bytes,
1544                   expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1545 
1546     return expand_bytes;
1547   } else {
1548     return 0;
1549   }
1550 }
1551 
1552 void G1CollectorPolicy::print_tracing_info() const {
1553   _trace_young_gen_time_data.print();
1554   _trace_old_gen_time_data.print();
1555 }
1556 
1557 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1558 #ifndef PRODUCT
1559   _short_lived_surv_rate_group->print_surv_rate_summary();
1560   // add this call for any other surv rate groups
1561 #endif // PRODUCT
1562 }
1563 
1564 bool G1CollectorPolicy::is_young_list_full() const {
1565   uint young_list_length = _g1->young_list()->length();
1566   uint young_list_target_length = _young_list_target_length;
1567   return young_list_length >= young_list_target_length;
1568 }
1569 
1570 bool G1CollectorPolicy::can_expand_young_list() const {
1571   uint young_list_length = _g1->young_list()->length();
1572   uint young_list_max_length = _young_list_max_length;
1573   return young_list_length < young_list_max_length;
1574 }
1575 
1576 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1577   uint expansion_region_num = 0;
1578   if (GCLockerEdenExpansionPercent > 0) {
1579     double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1580     double expansion_region_num_d = perc * (double) _young_list_target_length;
1581     // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1582     // less than 1.0) we'll get 1.
1583     expansion_region_num = (uint) ceil(expansion_region_num_d);
1584   } else {
1585     assert(expansion_region_num == 0, "sanity");
1586   }
1587   _young_list_max_length = _young_list_target_length + expansion_region_num;
1588   assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1589 }
1590 
1591 // Calculates survivor space parameters.
1592 void G1CollectorPolicy::update_survivors_policy() {
1593   double max_survivor_regions_d =
1594                  (double) _young_list_target_length / (double) SurvivorRatio;
1595   // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1596   // smaller than 1.0) we'll get 1.
1597   _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1598 
1599   _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1600         HeapRegion::GrainWords * _max_survivor_regions, counters());
1601 }
1602 
1603 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause) {
1604   // We actually check whether we are marking here and not if we are in a
1605   // reclamation phase. This means that we will schedule a concurrent mark
1606   // even while we are still in the process of reclaiming memory.
1607   bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1608   if (!during_cycle) {
1609     ergo_verbose1(ErgoConcCycles,
1610                   "request concurrent cycle initiation",
1611                   ergo_format_reason("requested by GC cause")
1612                   ergo_format_str("GC cause"),
1613                   GCCause::to_string(gc_cause));
1614     collector_state()->set_initiate_conc_mark_if_possible(true);
1615     return true;
1616   } else {
1617     ergo_verbose1(ErgoConcCycles,
1618                   "do not request concurrent cycle initiation",
1619                   ergo_format_reason("concurrent cycle already in progress")
1620                   ergo_format_str("GC cause"),
1621                   GCCause::to_string(gc_cause));
1622     return false;
1623   }
1624 }
1625 
1626 void G1CollectorPolicy::decide_on_conc_mark_initiation() {
1627   // We are about to decide on whether this pause will be an
1628   // initial-mark pause.
1629 
1630   // First, collector_state()->during_initial_mark_pause() should not be already set. We
1631   // will set it here if we have to. However, it should be cleared by
1632   // the end of the pause (it's only set for the duration of an
1633   // initial-mark pause).
1634   assert(!collector_state()->during_initial_mark_pause(), "pre-condition");
1635 
1636   if (collector_state()->initiate_conc_mark_if_possible()) {
1637     // We had noticed on a previous pause that the heap occupancy has
1638     // gone over the initiating threshold and we should start a
1639     // concurrent marking cycle. So we might initiate one.
1640 
1641     if (!about_to_start_mixed_phase() && collector_state()->gcs_are_young()) {
1642       // Initiate a new initial mark only if there is no marking or reclamation going
1643       // on.
1644 
1645       collector_state()->set_during_initial_mark_pause(true);
1646       // And we can now clear initiate_conc_mark_if_possible() as
1647       // we've already acted on it.
1648       collector_state()->set_initiate_conc_mark_if_possible(false);
1649 
1650       ergo_verbose0(ErgoConcCycles,
1651                   "initiate concurrent cycle",
1652                   ergo_format_reason("concurrent cycle initiation requested"));
1653     } else {
1654       // The concurrent marking thread is still finishing up the
1655       // previous cycle. If we start one right now the two cycles
1656       // overlap. In particular, the concurrent marking thread might
1657       // be in the process of clearing the next marking bitmap (which
1658       // we will use for the next cycle if we start one). Starting a
1659       // cycle now will be bad given that parts of the marking
1660       // information might get cleared by the marking thread. And we
1661       // cannot wait for the marking thread to finish the cycle as it
1662       // periodically yields while clearing the next marking bitmap
1663       // and, if it's in a yield point, it's waiting for us to
1664       // finish. So, at this point we will not start a cycle and we'll
1665       // let the concurrent marking thread complete the last one.
1666       ergo_verbose0(ErgoConcCycles,
1667                     "do not initiate concurrent cycle",
1668                     ergo_format_reason("concurrent cycle already in progress"));
1669     }
1670   }
1671 }
1672 
1673 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1674   G1CollectedHeap* _g1h;
1675   CSetChooserParUpdater _cset_updater;
1676 
1677 public:
1678   ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1679                            uint chunk_size) :
1680     _g1h(G1CollectedHeap::heap()),
1681     _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1682 
1683   bool doHeapRegion(HeapRegion* r) {
1684     // Do we have any marking information for this region?
1685     if (r->is_marked()) {
1686       // We will skip any region that's currently used as an old GC
1687       // alloc region (we should not consider those for collection
1688       // before we fill them up).
1689       if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1690         _cset_updater.add_region(r);
1691       }
1692     }
1693     return false;
1694   }
1695 };
1696 
1697 class ParKnownGarbageTask: public AbstractGangTask {
1698   CollectionSetChooser* _hrSorted;
1699   uint _chunk_size;
1700   G1CollectedHeap* _g1;
1701   HeapRegionClaimer _hrclaimer;
1702 
1703 public:
1704   ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
1705       AbstractGangTask("ParKnownGarbageTask"),
1706       _hrSorted(hrSorted), _chunk_size(chunk_size),
1707       _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
1708 
1709   void work(uint worker_id) {
1710     ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1711     _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
1712   }
1713 };
1714 
1715 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const {
1716   assert(n_workers > 0, "Active gc workers should be greater than 0");
1717   const uint overpartition_factor = 4;
1718   const uint min_chunk_size = MAX2(n_regions / n_workers, 1U);
1719   return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size);
1720 }
1721 
1722 void
1723 G1CollectorPolicy::record_concurrent_mark_cleanup_end() {
1724   _collectionSetChooser->clear();
1725 
1726   WorkGang* workers = _g1->workers();
1727   uint n_workers = workers->active_workers();
1728 
1729   uint n_regions = _g1->num_regions();
1730   uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions);
1731   _collectionSetChooser->prepare_for_par_region_addition(n_workers, n_regions, chunk_size);
1732   ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers);
1733   workers->run_task(&par_known_garbage_task);
1734 
1735   _collectionSetChooser->sort_regions();
1736 
1737   double end_sec = os::elapsedTime();
1738   double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1739   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1740   _cur_mark_stop_world_time_ms += elapsed_time_ms;
1741   _prev_collection_pause_end_ms += elapsed_time_ms;
1742   _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec);

1743 }
1744 
1745 // Add the heap region at the head of the non-incremental collection set
1746 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1747   assert(_inc_cset_build_state == Active, "Precondition");
1748   assert(hr->is_old(), "the region should be old");
1749 
1750   assert(!hr->in_collection_set(), "should not already be in the CSet");
1751   _g1->register_old_region_with_cset(hr);
1752   hr->set_next_in_collection_set(_collection_set);
1753   _collection_set = hr;
1754   _collection_set_bytes_used_before += hr->used();
1755   size_t rs_length = hr->rem_set()->occupied();
1756   _recorded_rs_lengths += rs_length;
1757   _old_cset_region_length += 1;
1758 }
1759 
1760 // Initialize the per-collection-set information
1761 void G1CollectorPolicy::start_incremental_cset_building() {
1762   assert(_inc_cset_build_state == Inactive, "Precondition");
1763 
1764   _inc_cset_head = NULL;
1765   _inc_cset_tail = NULL;
1766   _inc_cset_bytes_used_before = 0;
1767 
1768   _inc_cset_max_finger = 0;
1769   _inc_cset_recorded_rs_lengths = 0;
1770   _inc_cset_recorded_rs_lengths_diffs = 0;
1771   _inc_cset_predicted_elapsed_time_ms = 0.0;
1772   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1773   _inc_cset_build_state = Active;
1774 }
1775 
1776 void G1CollectorPolicy::finalize_incremental_cset_building() {
1777   assert(_inc_cset_build_state == Active, "Precondition");
1778   assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1779 
1780   // The two "main" fields, _inc_cset_recorded_rs_lengths and
1781   // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1782   // that adds a new region to the CSet. Further updates by the
1783   // concurrent refinement thread that samples the young RSet lengths
1784   // are accumulated in the *_diffs fields. Here we add the diffs to
1785   // the "main" fields.
1786 
1787   if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1788     _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1789   } else {
1790     // This is defensive. The diff should in theory be always positive
1791     // as RSets can only grow between GCs. However, given that we
1792     // sample their size concurrently with other threads updating them
1793     // it's possible that we might get the wrong size back, which
1794     // could make the calculations somewhat inaccurate.
1795     size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1796     if (_inc_cset_recorded_rs_lengths >= diffs) {
1797       _inc_cset_recorded_rs_lengths -= diffs;
1798     } else {
1799       _inc_cset_recorded_rs_lengths = 0;
1800     }
1801   }
1802   _inc_cset_predicted_elapsed_time_ms +=
1803                                      _inc_cset_predicted_elapsed_time_ms_diffs;
1804 
1805   _inc_cset_recorded_rs_lengths_diffs = 0;
1806   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1807 }
1808 
1809 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1810   // This routine is used when:
1811   // * adding survivor regions to the incremental cset at the end of an
1812   //   evacuation pause,
1813   // * adding the current allocation region to the incremental cset
1814   //   when it is retired, and
1815   // * updating existing policy information for a region in the
1816   //   incremental cset via young list RSet sampling.
1817   // Therefore this routine may be called at a safepoint by the
1818   // VM thread, or in-between safepoints by mutator threads (when
1819   // retiring the current allocation region) or a concurrent
1820   // refine thread (RSet sampling).
1821 
1822   double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1823   size_t used_bytes = hr->used();
1824   _inc_cset_recorded_rs_lengths += rs_length;
1825   _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1826   _inc_cset_bytes_used_before += used_bytes;
1827 
1828   // Cache the values we have added to the aggregated information
1829   // in the heap region in case we have to remove this region from
1830   // the incremental collection set, or it is updated by the
1831   // rset sampling code
1832   hr->set_recorded_rs_length(rs_length);
1833   hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1834 }
1835 
1836 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1837                                                      size_t new_rs_length) {
1838   // Update the CSet information that is dependent on the new RS length
1839   assert(hr->is_young(), "Precondition");
1840   assert(!SafepointSynchronize::is_at_safepoint(),
1841                                                "should not be at a safepoint");
1842 
1843   // We could have updated _inc_cset_recorded_rs_lengths and
1844   // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1845   // that atomically, as this code is executed by a concurrent
1846   // refinement thread, potentially concurrently with a mutator thread
1847   // allocating a new region and also updating the same fields. To
1848   // avoid the atomic operations we accumulate these updates on two
1849   // separate fields (*_diffs) and we'll just add them to the "main"
1850   // fields at the start of a GC.
1851 
1852   ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1853   ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1854   _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1855 
1856   double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1857   double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1858   double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1859   _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1860 
1861   hr->set_recorded_rs_length(new_rs_length);
1862   hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1863 }
1864 
1865 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1866   assert(hr->is_young(), "invariant");
1867   assert(hr->young_index_in_cset() > -1, "should have already been set");
1868   assert(_inc_cset_build_state == Active, "Precondition");
1869 
1870   // We need to clear and set the cached recorded/cached collection set
1871   // information in the heap region here (before the region gets added
1872   // to the collection set). An individual heap region's cached values
1873   // are calculated, aggregated with the policy collection set info,
1874   // and cached in the heap region here (initially) and (subsequently)
1875   // by the Young List sampling code.
1876 
1877   size_t rs_length = hr->rem_set()->occupied();
1878   add_to_incremental_cset_info(hr, rs_length);
1879 
1880   HeapWord* hr_end = hr->end();
1881   _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1882 
1883   assert(!hr->in_collection_set(), "invariant");
1884   _g1->register_young_region_with_cset(hr);
1885   assert(hr->next_in_collection_set() == NULL, "invariant");
1886 }
1887 
1888 // Add the region at the RHS of the incremental cset
1889 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1890   // We should only ever be appending survivors at the end of a pause
1891   assert(hr->is_survivor(), "Logic");
1892 
1893   // Do the 'common' stuff
1894   add_region_to_incremental_cset_common(hr);
1895 
1896   // Now add the region at the right hand side
1897   if (_inc_cset_tail == NULL) {
1898     assert(_inc_cset_head == NULL, "invariant");
1899     _inc_cset_head = hr;
1900   } else {
1901     _inc_cset_tail->set_next_in_collection_set(hr);
1902   }
1903   _inc_cset_tail = hr;
1904 }
1905 
1906 // Add the region to the LHS of the incremental cset
1907 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1908   // Survivors should be added to the RHS at the end of a pause
1909   assert(hr->is_eden(), "Logic");
1910 
1911   // Do the 'common' stuff
1912   add_region_to_incremental_cset_common(hr);
1913 
1914   // Add the region at the left hand side
1915   hr->set_next_in_collection_set(_inc_cset_head);
1916   if (_inc_cset_head == NULL) {
1917     assert(_inc_cset_tail == NULL, "Invariant");
1918     _inc_cset_tail = hr;
1919   }
1920   _inc_cset_head = hr;
1921 }
1922 
1923 #ifndef PRODUCT
1924 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1925   assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1926 
1927   st->print_cr("\nCollection_set:");
1928   HeapRegion* csr = list_head;
1929   while (csr != NULL) {
1930     HeapRegion* next = csr->next_in_collection_set();
1931     assert(csr->in_collection_set(), "bad CS");
1932     st->print_cr("  " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d",
1933                  HR_FORMAT_PARAMS(csr),
1934                  p2i(csr->prev_top_at_mark_start()), p2i(csr->next_top_at_mark_start()),
1935                  csr->age_in_surv_rate_group_cond());
1936     csr = next;
1937   }
1938 }
1939 #endif // !PRODUCT
1940 
1941 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) const {
1942   // Returns the given amount of reclaimable bytes (that represents
1943   // the amount of reclaimable space still to be collected) as a
1944   // percentage of the current heap capacity.
1945   size_t capacity_bytes = _g1->capacity();
1946   return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1947 }
1948 
1949 void G1CollectorPolicy::maybe_start_marking() {
1950   if (need_to_start_conc_mark("end of GC")) {
1951     // Note: this might have already been set, if during the last
1952     // pause we decided to start a cycle but at the beginning of
1953     // this pause we decided to postpone it. That's OK.
1954     collector_state()->set_initiate_conc_mark_if_possible(true);
1955   }  





















































1956 }
1957 
1958 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1959                                                 const char* false_action_str) const {
1960   CollectionSetChooser* cset_chooser = _collectionSetChooser;
1961   if (cset_chooser->is_empty()) {
1962     ergo_verbose0(ErgoMixedGCs,
1963                   false_action_str,
1964                   ergo_format_reason("candidate old regions not available"));
1965     return false;
1966   }
1967 
1968   // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1969   size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1970   double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1971   double threshold = (double) G1HeapWastePercent;
1972   if (reclaimable_perc <= threshold) {
1973     ergo_verbose4(ErgoMixedGCs,
1974               false_action_str,
1975               ergo_format_reason("reclaimable percentage not over threshold")
1976               ergo_format_region("candidate old regions")
1977               ergo_format_byte_perc("reclaimable")
1978               ergo_format_perc("threshold"),
1979               cset_chooser->remaining_regions(),
1980               reclaimable_bytes,
1981               reclaimable_perc, threshold);
1982     return false;
1983   }
1984 
1985   ergo_verbose4(ErgoMixedGCs,
1986                 true_action_str,
1987                 ergo_format_reason("candidate old regions available")
1988                 ergo_format_region("candidate old regions")
1989                 ergo_format_byte_perc("reclaimable")
1990                 ergo_format_perc("threshold"),
1991                 cset_chooser->remaining_regions(),
1992                 reclaimable_bytes,
1993                 reclaimable_perc, threshold);
1994   return true;
1995 }
1996 
1997 uint G1CollectorPolicy::calc_min_old_cset_length() const {
1998   // The min old CSet region bound is based on the maximum desired
1999   // number of mixed GCs after a cycle. I.e., even if some old regions
2000   // look expensive, we should add them to the CSet anyway to make
2001   // sure we go through the available old regions in no more than the
2002   // maximum desired number of mixed GCs.
2003   //
2004   // The calculation is based on the number of marked regions we added
2005   // to the CSet chooser in the first place, not how many remain, so
2006   // that the result is the same during all mixed GCs that follow a cycle.
2007 
2008   const size_t region_num = (size_t) _collectionSetChooser->length();
2009   const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
2010   size_t result = region_num / gc_num;
2011   // emulate ceiling
2012   if (result * gc_num < region_num) {
2013     result += 1;
2014   }
2015   return (uint) result;
2016 }
2017 
2018 uint G1CollectorPolicy::calc_max_old_cset_length() const {
2019   // The max old CSet region bound is based on the threshold expressed
2020   // as a percentage of the heap size. I.e., it should bound the
2021   // number of old regions added to the CSet irrespective of how many
2022   // of them are available.
2023 
2024   const G1CollectedHeap* g1h = G1CollectedHeap::heap();
2025   const size_t region_num = g1h->num_regions();
2026   const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
2027   size_t result = region_num * perc / 100;
2028   // emulate ceiling
2029   if (100 * result < region_num * perc) {
2030     result += 1;
2031   }
2032   return (uint) result;
2033 }
2034 
2035 
2036 double G1CollectorPolicy::finalize_young_cset_part(double target_pause_time_ms) {
2037   double young_start_time_sec = os::elapsedTime();
2038 
2039   YoungList* young_list = _g1->young_list();
2040   finalize_incremental_cset_building();
2041 
2042   guarantee(target_pause_time_ms > 0.0,
2043             "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms);
2044   guarantee(_collection_set == NULL, "Precondition");
2045 
2046   double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2047   double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
2048 
2049   ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
2050                 "start choosing CSet",
2051                 ergo_format_size("_pending_cards")
2052                 ergo_format_ms("predicted base time")
2053                 ergo_format_ms("remaining time")
2054                 ergo_format_ms("target pause time"),
2055                 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
2056 
2057   collector_state()->set_last_gc_was_young(collector_state()->gcs_are_young());
2058 
2059   if (collector_state()->last_gc_was_young()) {
2060     _trace_young_gen_time_data.increment_young_collection_count();
2061   } else {
2062     _trace_young_gen_time_data.increment_mixed_collection_count();
2063   }
2064 
2065   // The young list is laid with the survivor regions from the previous
2066   // pause are appended to the RHS of the young list, i.e.
2067   //   [Newly Young Regions ++ Survivors from last pause].
2068 
2069   uint survivor_region_length = young_list->survivor_length();
2070   uint eden_region_length = young_list->eden_length();
2071   init_cset_region_lengths(eden_region_length, survivor_region_length);
2072 
2073   HeapRegion* hr = young_list->first_survivor_region();
2074   while (hr != NULL) {
2075     assert(hr->is_survivor(), "badly formed young list");
2076     // There is a convention that all the young regions in the CSet
2077     // are tagged as "eden", so we do this for the survivors here. We
2078     // use the special set_eden_pre_gc() as it doesn't check that the
2079     // region is free (which is not the case here).
2080     hr->set_eden_pre_gc();
2081     hr = hr->get_next_young_region();
2082   }
2083 
2084   // Clear the fields that point to the survivor list - they are all young now.
2085   young_list->clear_survivors();
2086 
2087   _collection_set = _inc_cset_head;
2088   _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2089   time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
2090 
2091   ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
2092                 "add young regions to CSet",
2093                 ergo_format_region("eden")
2094                 ergo_format_region("survivors")
2095                 ergo_format_ms("predicted young region time")
2096                 ergo_format_ms("target pause time"),
2097                 eden_region_length, survivor_region_length,
2098                 _inc_cset_predicted_elapsed_time_ms,
2099                 target_pause_time_ms);
2100 
2101   // The number of recorded young regions is the incremental
2102   // collection set's current size
2103   set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2104 
2105   double young_end_time_sec = os::elapsedTime();
2106   phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
2107 
2108   return time_remaining_ms;
2109 }
2110 
2111 void G1CollectorPolicy::finalize_old_cset_part(double time_remaining_ms) {
2112   double non_young_start_time_sec = os::elapsedTime();
2113   double predicted_old_time_ms = 0.0;
2114 
2115 
2116   if (!collector_state()->gcs_are_young()) {
2117     CollectionSetChooser* cset_chooser = _collectionSetChooser;
2118     cset_chooser->verify();
2119     const uint min_old_cset_length = calc_min_old_cset_length();
2120     const uint max_old_cset_length = calc_max_old_cset_length();
2121 
2122     uint expensive_region_num = 0;
2123     bool check_time_remaining = adaptive_young_list_length();
2124 
2125     HeapRegion* hr = cset_chooser->peek();
2126     while (hr != NULL) {
2127       if (old_cset_region_length() >= max_old_cset_length) {
2128         // Added maximum number of old regions to the CSet.
2129         ergo_verbose2(ErgoCSetConstruction,
2130                       "finish adding old regions to CSet",
2131                       ergo_format_reason("old CSet region num reached max")
2132                       ergo_format_region("old")
2133                       ergo_format_region("max"),
2134                       old_cset_region_length(), max_old_cset_length);
2135         break;
2136       }
2137 
2138 
2139       // Stop adding regions if the remaining reclaimable space is
2140       // not above G1HeapWastePercent.
2141       size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
2142       double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
2143       double threshold = (double) G1HeapWastePercent;
2144       if (reclaimable_perc <= threshold) {
2145         // We've added enough old regions that the amount of uncollected
2146         // reclaimable space is at or below the waste threshold. Stop
2147         // adding old regions to the CSet.
2148         ergo_verbose5(ErgoCSetConstruction,
2149                       "finish adding old regions to CSet",
2150                       ergo_format_reason("reclaimable percentage not over threshold")
2151                       ergo_format_region("old")
2152                       ergo_format_region("max")
2153                       ergo_format_byte_perc("reclaimable")
2154                       ergo_format_perc("threshold"),
2155                       old_cset_region_length(),
2156                       max_old_cset_length,
2157                       reclaimable_bytes,
2158                       reclaimable_perc, threshold);
2159         break;
2160       }
2161 
2162       double predicted_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
2163       if (check_time_remaining) {
2164         if (predicted_time_ms > time_remaining_ms) {
2165           // Too expensive for the current CSet.
2166 
2167           if (old_cset_region_length() >= min_old_cset_length) {
2168             // We have added the minimum number of old regions to the CSet,
2169             // we are done with this CSet.
2170             ergo_verbose4(ErgoCSetConstruction,
2171                           "finish adding old regions to CSet",
2172                           ergo_format_reason("predicted time is too high")
2173                           ergo_format_ms("predicted time")
2174                           ergo_format_ms("remaining time")
2175                           ergo_format_region("old")
2176                           ergo_format_region("min"),
2177                           predicted_time_ms, time_remaining_ms,
2178                           old_cset_region_length(), min_old_cset_length);
2179             break;
2180           }
2181 
2182           // We'll add it anyway given that we haven't reached the
2183           // minimum number of old regions.
2184           expensive_region_num += 1;
2185         }
2186       } else {
2187         if (old_cset_region_length() >= min_old_cset_length) {
2188           // In the non-auto-tuning case, we'll finish adding regions
2189           // to the CSet if we reach the minimum.
2190           ergo_verbose2(ErgoCSetConstruction,
2191                         "finish adding old regions to CSet",
2192                         ergo_format_reason("old CSet region num reached min")
2193                         ergo_format_region("old")
2194                         ergo_format_region("min"),
2195                         old_cset_region_length(), min_old_cset_length);
2196           break;
2197         }
2198       }
2199 
2200       // We will add this region to the CSet.
2201       time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2202       predicted_old_time_ms += predicted_time_ms;
2203       cset_chooser->pop(); // already have region via peek()
2204       _g1->old_set_remove(hr);
2205       add_old_region_to_cset(hr);
2206 
2207       hr = cset_chooser->peek();
2208     }
2209     if (hr == NULL) {
2210       ergo_verbose0(ErgoCSetConstruction,
2211                     "finish adding old regions to CSet",
2212                     ergo_format_reason("candidate old regions not available"));
2213     }
2214 
2215     if (expensive_region_num > 0) {
2216       // We print the information once here at the end, predicated on
2217       // whether we added any apparently expensive regions or not, to
2218       // avoid generating output per region.
2219       ergo_verbose4(ErgoCSetConstruction,
2220                     "added expensive regions to CSet",
2221                     ergo_format_reason("old CSet region num not reached min")
2222                     ergo_format_region("old")
2223                     ergo_format_region("expensive")
2224                     ergo_format_region("min")
2225                     ergo_format_ms("remaining time"),
2226                     old_cset_region_length(),
2227                     expensive_region_num,
2228                     min_old_cset_length,
2229                     time_remaining_ms);
2230     }
2231 
2232     cset_chooser->verify();
2233   }
2234 
2235   stop_incremental_cset_building();
2236 
2237   ergo_verbose3(ErgoCSetConstruction,
2238                 "finish choosing CSet",
2239                 ergo_format_region("old")
2240                 ergo_format_ms("predicted old region time")
2241                 ergo_format_ms("time remaining"),
2242                 old_cset_region_length(),
2243                 predicted_old_time_ms, time_remaining_ms);
2244 
2245   double non_young_end_time_sec = os::elapsedTime();
2246   phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2247 }
2248 
2249 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) {
2250   if(TraceYoungGenTime) {
2251     _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2252   }
2253 }
2254 
2255 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) {
2256   if(TraceYoungGenTime) {
2257     _all_yield_times_ms.add(yield_time_ms);
2258   }
2259 }
2260 
2261 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2262   if(TraceYoungGenTime) {
2263     _total.add(pause_time_ms);
2264     _other.add(pause_time_ms - phase_times->accounted_time_ms());
2265     _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2266     _parallel.add(phase_times->cur_collection_par_time_ms());
2267     _ext_root_scan.add(phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan));
2268     _satb_filtering.add(phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering));
2269     _update_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS));
2270     _scan_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::ScanRS));
2271     _obj_copy.add(phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy));
2272     _termination.add(phase_times->average_time_ms(G1GCPhaseTimes::Termination));
2273 
2274     double parallel_known_time = phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan) +
2275       phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering) +
2276       phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS) +
2277       phase_times->average_time_ms(G1GCPhaseTimes::ScanRS) +
2278       phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy) +
2279       phase_times->average_time_ms(G1GCPhaseTimes::Termination);
2280 
2281     double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2282     _parallel_other.add(parallel_other_time);
2283     _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2284   }
2285 }
2286 
2287 void TraceYoungGenTimeData::increment_young_collection_count() {
2288   if(TraceYoungGenTime) {
2289     ++_young_pause_num;
2290   }
2291 }
2292 
2293 void TraceYoungGenTimeData::increment_mixed_collection_count() {
2294   if(TraceYoungGenTime) {
2295     ++_mixed_pause_num;
2296   }
2297 }
2298 
2299 void TraceYoungGenTimeData::print_summary(const char* str,
2300                                           const NumberSeq* seq) const {
2301   double sum = seq->sum();
2302   gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2303                 str, sum / 1000.0, seq->avg());
2304 }
2305 
2306 void TraceYoungGenTimeData::print_summary_sd(const char* str,
2307                                              const NumberSeq* seq) const {
2308   print_summary(str, seq);
2309   gclog_or_tty->print_cr("%45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2310                 "(num", seq->num(), seq->sd(), seq->maximum());
2311 }
2312 
2313 void TraceYoungGenTimeData::print() const {
2314   if (!TraceYoungGenTime) {
2315     return;
2316   }
2317 
2318   gclog_or_tty->print_cr("ALL PAUSES");
2319   print_summary_sd("   Total", &_total);
2320   gclog_or_tty->cr();
2321   gclog_or_tty->cr();
2322   gclog_or_tty->print_cr("   Young GC Pauses: %8d", _young_pause_num);
2323   gclog_or_tty->print_cr("   Mixed GC Pauses: %8d", _mixed_pause_num);
2324   gclog_or_tty->cr();
2325 
2326   gclog_or_tty->print_cr("EVACUATION PAUSES");
2327 
2328   if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2329     gclog_or_tty->print_cr("none");
2330   } else {
2331     print_summary_sd("   Evacuation Pauses", &_total);
2332     print_summary("      Root Region Scan Wait", &_root_region_scan_wait);
2333     print_summary("      Parallel Time", &_parallel);
2334     print_summary("         Ext Root Scanning", &_ext_root_scan);
2335     print_summary("         SATB Filtering", &_satb_filtering);
2336     print_summary("         Update RS", &_update_rs);
2337     print_summary("         Scan RS", &_scan_rs);
2338     print_summary("         Object Copy", &_obj_copy);
2339     print_summary("         Termination", &_termination);
2340     print_summary("         Parallel Other", &_parallel_other);
2341     print_summary("      Clear CT", &_clear_ct);
2342     print_summary("      Other", &_other);
2343   }
2344   gclog_or_tty->cr();
2345 
2346   gclog_or_tty->print_cr("MISC");
2347   print_summary_sd("   Stop World", &_all_stop_world_times_ms);
2348   print_summary_sd("   Yields", &_all_yield_times_ms);
2349 }
2350 
2351 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) {
2352   if (TraceOldGenTime) {
2353     _all_full_gc_times.add(full_gc_time_ms);
2354   }
2355 }
2356 
2357 void TraceOldGenTimeData::print() const {
2358   if (!TraceOldGenTime) {
2359     return;
2360   }
2361 
2362   if (_all_full_gc_times.num() > 0) {
2363     gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2364       _all_full_gc_times.num(),
2365       _all_full_gc_times.sum() / 1000.0);
2366     gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2367     gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
2368       _all_full_gc_times.sd(),
2369       _all_full_gc_times.maximum());
2370   }
2371 }
--- EOF ---