1 /*
   2  * Copyright (c) 2001, 2014, 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 #ifndef __clang_major__
  26 // FIXME, formats have issues.  Disable this macro definition, compile, and study warnings for more information.
  27 #define ATTRIBUTE_PRINTF(x,y)
  28 #endif
  29 
  30 #include "precompiled.hpp"
  31 #include "gc_implementation/g1/concurrentG1Refine.hpp"
  32 #include "gc_implementation/g1/concurrentMark.hpp"
  33 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
  34 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
  35 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
  36 #include "gc_implementation/g1/g1ErgoVerbose.hpp"
  37 #include "gc_implementation/g1/g1GCPhaseTimes.hpp"
  38 #include "gc_implementation/g1/g1Log.hpp"
  39 #include "gc_implementation/g1/heapRegionRemSet.hpp"
  40 #include "gc_implementation/shared/gcPolicyCounters.hpp"
  41 #include "runtime/arguments.hpp"
  42 #include "runtime/java.hpp"
  43 #include "runtime/mutexLocker.hpp"
  44 #include "utilities/debug.hpp"
  45 
  46 // Different defaults for different number of GC threads
  47 // They were chosen by running GCOld and SPECjbb on debris with different
  48 //   numbers of GC threads and choosing them based on the results
  49 
  50 // all the same
  51 static double rs_length_diff_defaults[] = {
  52   0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
  53 };
  54 
  55 static double cost_per_card_ms_defaults[] = {
  56   0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
  57 };
  58 
  59 // all the same
  60 static double young_cards_per_entry_ratio_defaults[] = {
  61   1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
  62 };
  63 
  64 static double cost_per_entry_ms_defaults[] = {
  65   0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
  66 };
  67 
  68 static double cost_per_byte_ms_defaults[] = {
  69   0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
  70 };
  71 
  72 // these should be pretty consistent
  73 static double constant_other_time_ms_defaults[] = {
  74   5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
  75 };
  76 
  77 
  78 static double young_other_cost_per_region_ms_defaults[] = {
  79   0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
  80 };
  81 
  82 static double non_young_other_cost_per_region_ms_defaults[] = {
  83   1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
  84 };
  85 
  86 G1CollectorPolicy::G1CollectorPolicy() :
  87   _parallel_gc_threads(ParallelGCThreads),
  88 
  89   _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  90   _stop_world_start(0.0),
  91 
  92   _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  93   _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
  94 
  95   _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
  96   _prev_collection_pause_end_ms(0.0),
  97   _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
  98   _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
  99   _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
 100   _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
 101   _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 102   _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 103   _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 104   _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
 105   _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 106   _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
 107   _non_young_other_cost_per_region_ms_seq(
 108                                          new TruncatedSeq(TruncatedSeqLength)),
 109 
 110   _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
 111   _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
 112 
 113   _pause_time_target_ms((double) MaxGCPauseMillis),
 114 
 115   _gcs_are_young(true),
 116 
 117   _during_marking(false),
 118   _in_marking_window(false),
 119   _in_marking_window_im(false),
 120 
 121   _recent_prev_end_times_for_all_gcs_sec(
 122                                 new TruncatedSeq(NumPrevPausesForHeuristics)),
 123 
 124   _recent_avg_pause_time_ratio(0.0),
 125 
 126   _initiate_conc_mark_if_possible(false),
 127   _during_initial_mark_pause(false),
 128   _last_young_gc(false),
 129   _last_gc_was_young(false),
 130 
 131   _eden_used_bytes_before_gc(0),
 132   _survivor_used_bytes_before_gc(0),
 133   _heap_used_bytes_before_gc(0),
 134   _metaspace_used_bytes_before_gc(0),
 135   _eden_capacity_bytes_before_gc(0),
 136   _heap_capacity_bytes_before_gc(0),
 137 
 138   _eden_cset_region_length(0),
 139   _survivor_cset_region_length(0),
 140   _old_cset_region_length(0),
 141 
 142   _collection_set(NULL),
 143   _collection_set_bytes_used_before(0),
 144 
 145   // Incremental CSet attributes
 146   _inc_cset_build_state(Inactive),
 147   _inc_cset_head(NULL),
 148   _inc_cset_tail(NULL),
 149   _inc_cset_bytes_used_before(0),
 150   _inc_cset_max_finger(NULL),
 151   _inc_cset_recorded_rs_lengths(0),
 152   _inc_cset_recorded_rs_lengths_diffs(0),
 153   _inc_cset_predicted_elapsed_time_ms(0.0),
 154   _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
 155 
 156 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
 157 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
 158 #endif // _MSC_VER
 159 
 160   _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
 161                                                  G1YoungSurvRateNumRegionsSummary)),
 162   _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
 163                                               G1YoungSurvRateNumRegionsSummary)),
 164   // add here any more surv rate groups
 165   _recorded_survivor_regions(0),
 166   _recorded_survivor_head(NULL),
 167   _recorded_survivor_tail(NULL),
 168   _survivors_age_table(true),
 169 
 170   _gc_overhead_perc(0.0) {
 171 
 172   // Set up the region size and associated fields. Given that the
 173   // policy is created before the heap, we have to set this up here,
 174   // so it's done as soon as possible.
 175 
 176   // It would have been natural to pass initial_heap_byte_size() and
 177   // max_heap_byte_size() to setup_heap_region_size() but those have
 178   // not been set up at this point since they should be aligned with
 179   // the region size. So, there is a circular dependency here. We base
 180   // the region size on the heap size, but the heap size should be
 181   // aligned with the region size. To get around this we use the
 182   // unaligned values for the heap.
 183   HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
 184   HeapRegionRemSet::setup_remset_size();
 185 
 186   G1ErgoVerbose::initialize();
 187   if (PrintAdaptiveSizePolicy) {
 188     // Currently, we only use a single switch for all the heuristics.
 189     G1ErgoVerbose::set_enabled(true);
 190     // Given that we don't currently have a verboseness level
 191     // parameter, we'll hardcode this to high. This can be easily
 192     // changed in the future.
 193     G1ErgoVerbose::set_level(ErgoHigh);
 194   } else {
 195     G1ErgoVerbose::set_enabled(false);
 196   }
 197 
 198   // Verify PLAB sizes
 199   const size_t region_size = HeapRegion::GrainWords;
 200   if (YoungPLABSize > region_size || OldPLABSize > region_size) {
 201     char buffer[128];
 202     jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT,
 203                  OldPLABSize > region_size ? "Old" : "Young", region_size);
 204     vm_exit_during_initialization(buffer);
 205   }
 206 
 207   _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
 208   _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
 209 
 210   _phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
 211 
 212   int index = MIN2(_parallel_gc_threads - 1, 7);
 213 
 214   _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
 215   _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
 216   _young_cards_per_entry_ratio_seq->add(
 217                                   young_cards_per_entry_ratio_defaults[index]);
 218   _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
 219   _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
 220   _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
 221   _young_other_cost_per_region_ms_seq->add(
 222                                young_other_cost_per_region_ms_defaults[index]);
 223   _non_young_other_cost_per_region_ms_seq->add(
 224                            non_young_other_cost_per_region_ms_defaults[index]);
 225 
 226   // Below, we might need to calculate the pause time target based on
 227   // the pause interval. When we do so we are going to give G1 maximum
 228   // flexibility and allow it to do pauses when it needs to. So, we'll
 229   // arrange that the pause interval to be pause time target + 1 to
 230   // ensure that a) the pause time target is maximized with respect to
 231   // the pause interval and b) we maintain the invariant that pause
 232   // time target < pause interval. If the user does not want this
 233   // maximum flexibility, they will have to set the pause interval
 234   // explicitly.
 235 
 236   // First make sure that, if either parameter is set, its value is
 237   // reasonable.
 238   if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
 239     if (MaxGCPauseMillis < 1) {
 240       vm_exit_during_initialization("MaxGCPauseMillis should be "
 241                                     "greater than 0");
 242     }
 243   }
 244   if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 245     if (GCPauseIntervalMillis < 1) {
 246       vm_exit_during_initialization("GCPauseIntervalMillis should be "
 247                                     "greater than 0");
 248     }
 249   }
 250 
 251   // Then, if the pause time target parameter was not set, set it to
 252   // the default value.
 253   if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
 254     if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 255       // The default pause time target in G1 is 200ms
 256       FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
 257     } else {
 258       // We do not allow the pause interval to be set without the
 259       // pause time target
 260       vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
 261                                     "without setting MaxGCPauseMillis");
 262     }
 263   }
 264 
 265   // Then, if the interval parameter was not set, set it according to
 266   // the pause time target (this will also deal with the case when the
 267   // pause time target is the default value).
 268   if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
 269     FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
 270   }
 271 
 272   // Finally, make sure that the two parameters are consistent.
 273   if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
 274     char buffer[256];
 275     jio_snprintf(buffer, 256,
 276                  "MaxGCPauseMillis (%u) should be less than "
 277                  "GCPauseIntervalMillis (%u)",
 278                  MaxGCPauseMillis, GCPauseIntervalMillis);
 279     vm_exit_during_initialization(buffer);
 280   }
 281 
 282   double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
 283   double time_slice  = (double) GCPauseIntervalMillis / 1000.0;
 284   _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
 285 
 286   uintx confidence_perc = G1ConfidencePercent;
 287   // Put an artificial ceiling on this so that it's not set to a silly value.
 288   if (confidence_perc > 100) {
 289     confidence_perc = 100;
 290     warning("G1ConfidencePercent is set to a value that is too large, "
 291             "it's been updated to %u", confidence_perc);
 292   }
 293   _sigma = (double) confidence_perc / 100.0;
 294 
 295   // start conservatively (around 50ms is about right)
 296   _concurrent_mark_remark_times_ms->add(0.05);
 297   _concurrent_mark_cleanup_times_ms->add(0.20);
 298   _tenuring_threshold = MaxTenuringThreshold;
 299   // _max_survivor_regions will be calculated by
 300   // update_young_list_target_length() during initialization.
 301   _max_survivor_regions = 0;
 302 
 303   assert(GCTimeRatio > 0,
 304          "we should have set it to a default value set_g1_gc_flags() "
 305          "if a user set it to 0");
 306   _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
 307 
 308   uintx reserve_perc = G1ReservePercent;
 309   // Put an artificial ceiling on this so that it's not set to a silly value.
 310   if (reserve_perc > 50) {
 311     reserve_perc = 50;
 312     warning("G1ReservePercent is set to a value that is too large, "
 313             "it's been updated to %u", reserve_perc);
 314   }
 315   _reserve_factor = (double) reserve_perc / 100.0;
 316   // This will be set when the heap is expanded
 317   // for the first time during initialization.
 318   _reserve_regions = 0;
 319 
 320   _collectionSetChooser = new CollectionSetChooser();
 321 }
 322 
 323 void G1CollectorPolicy::initialize_alignments() {
 324   _space_alignment = HeapRegion::GrainBytes;
 325   size_t card_table_alignment = GenRemSet::max_alignment_constraint();
 326   size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
 327   _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
 328 }
 329 
 330 void G1CollectorPolicy::initialize_flags() {
 331   if (G1HeapRegionSize != HeapRegion::GrainBytes) {
 332     FLAG_SET_ERGO(uintx, G1HeapRegionSize, HeapRegion::GrainBytes);
 333   }
 334 
 335   if (SurvivorRatio < 1) {
 336     vm_exit_during_initialization("Invalid survivor ratio specified");
 337   }
 338   CollectorPolicy::initialize_flags();
 339   _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
 340 }
 341 
 342 void G1CollectorPolicy::post_heap_initialize() {
 343   uintx max_regions = G1CollectedHeap::heap()->max_regions();
 344   size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
 345   if (max_young_size != MaxNewSize) {
 346     FLAG_SET_ERGO(uintx, MaxNewSize, max_young_size);
 347   }
 348 }
 349 
 350 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
 351         _min_desired_young_length(0), _max_desired_young_length(0) {
 352   if (FLAG_IS_CMDLINE(NewRatio)) {
 353     if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
 354       warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
 355     } else {
 356       _sizer_kind = SizerNewRatio;
 357       _adaptive_size = false;
 358       return;
 359     }
 360   }
 361 
 362   if (NewSize > MaxNewSize) {
 363     if (FLAG_IS_CMDLINE(MaxNewSize)) {
 364       warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
 365               "A new max generation size of " SIZE_FORMAT "k will be used.",
 366               NewSize/K, MaxNewSize/K, NewSize/K);
 367     }
 368     MaxNewSize = NewSize;
 369   }
 370 
 371   if (FLAG_IS_CMDLINE(NewSize)) {
 372     _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
 373                                      1U);
 374     if (FLAG_IS_CMDLINE(MaxNewSize)) {
 375       _max_desired_young_length =
 376                              MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
 377                                   1U);
 378       _sizer_kind = SizerMaxAndNewSize;
 379       _adaptive_size = _min_desired_young_length == _max_desired_young_length;
 380     } else {
 381       _sizer_kind = SizerNewSizeOnly;
 382     }
 383   } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
 384     _max_desired_young_length =
 385                              MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
 386                                   1U);
 387     _sizer_kind = SizerMaxNewSizeOnly;
 388   }
 389 }
 390 
 391 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
 392   uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
 393   return MAX2(1U, default_value);
 394 }
 395 
 396 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
 397   uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
 398   return MAX2(1U, default_value);
 399 }
 400 
 401 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
 402   assert(number_of_heap_regions > 0, "Heap must be initialized");
 403 
 404   switch (_sizer_kind) {
 405     case SizerDefaults:
 406       *min_young_length = calculate_default_min_length(number_of_heap_regions);
 407       *max_young_length = calculate_default_max_length(number_of_heap_regions);
 408       break;
 409     case SizerNewSizeOnly:
 410       *max_young_length = calculate_default_max_length(number_of_heap_regions);
 411       *max_young_length = MAX2(*min_young_length, *max_young_length);
 412       break;
 413     case SizerMaxNewSizeOnly:
 414       *min_young_length = calculate_default_min_length(number_of_heap_regions);
 415       *min_young_length = MIN2(*min_young_length, *max_young_length);
 416       break;
 417     case SizerMaxAndNewSize:
 418       // Do nothing. Values set on the command line, don't update them at runtime.
 419       break;
 420     case SizerNewRatio:
 421       *min_young_length = number_of_heap_regions / (NewRatio + 1);
 422       *max_young_length = *min_young_length;
 423       break;
 424     default:
 425       ShouldNotReachHere();
 426   }
 427 
 428   assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
 429 }
 430 
 431 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
 432   // We need to pass the desired values because recalculation may not update these
 433   // values in some cases.
 434   uint temp = _min_desired_young_length;
 435   uint result = _max_desired_young_length;
 436   recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
 437   return result;
 438 }
 439 
 440 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
 441   recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
 442           &_max_desired_young_length);
 443 }
 444 
 445 void G1CollectorPolicy::init() {
 446   // Set aside an initial future to_space.
 447   _g1 = G1CollectedHeap::heap();
 448 
 449   assert(Heap_lock->owned_by_self(), "Locking discipline.");
 450 
 451   initialize_gc_policy_counters();
 452 
 453   if (adaptive_young_list_length()) {
 454     _young_list_fixed_length = 0;
 455   } else {
 456     _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
 457   }
 458   _free_regions_at_end_of_collection = _g1->num_free_regions();
 459   update_young_list_target_length();
 460 
 461   // We may immediately start allocating regions and placing them on the
 462   // collection set list. Initialize the per-collection set info
 463   start_incremental_cset_building();
 464 }
 465 
 466 // Create the jstat counters for the policy.
 467 void G1CollectorPolicy::initialize_gc_policy_counters() {
 468   _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
 469 }
 470 
 471 bool G1CollectorPolicy::predict_will_fit(uint young_length,
 472                                          double base_time_ms,
 473                                          uint base_free_regions,
 474                                          double target_pause_time_ms) {
 475   if (young_length >= base_free_regions) {
 476     // end condition 1: not enough space for the young regions
 477     return false;
 478   }
 479 
 480   double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
 481   size_t bytes_to_copy =
 482                (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
 483   double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
 484   double young_other_time_ms = predict_young_other_time_ms(young_length);
 485   double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
 486   if (pause_time_ms > target_pause_time_ms) {
 487     // end condition 2: prediction is over the target pause time
 488     return false;
 489   }
 490 
 491   size_t free_bytes =
 492                    (base_free_regions - young_length) * HeapRegion::GrainBytes;
 493   if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
 494     // end condition 3: out-of-space (conservatively!)
 495     return false;
 496   }
 497 
 498   // success!
 499   return true;
 500 }
 501 
 502 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
 503   // re-calculate the necessary reserve
 504   double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
 505   // We use ceiling so that if reserve_regions_d is > 0.0 (but
 506   // smaller than 1.0) we'll get 1.
 507   _reserve_regions = (uint) ceil(reserve_regions_d);
 508 
 509   _young_gen_sizer->heap_size_changed(new_number_of_regions);
 510 }
 511 
 512 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
 513                                                        uint base_min_length) {
 514   uint desired_min_length = 0;
 515   if (adaptive_young_list_length()) {
 516     if (_alloc_rate_ms_seq->num() > 3) {
 517       double now_sec = os::elapsedTime();
 518       double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
 519       double alloc_rate_ms = predict_alloc_rate_ms();
 520       desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
 521     } else {
 522       // otherwise we don't have enough info to make the prediction
 523     }
 524   }
 525   desired_min_length += base_min_length;
 526   // make sure we don't go below any user-defined minimum bound
 527   return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
 528 }
 529 
 530 uint G1CollectorPolicy::calculate_young_list_desired_max_length() {
 531   // Here, we might want to also take into account any additional
 532   // constraints (i.e., user-defined minimum bound). Currently, we
 533   // effectively don't set this bound.
 534   return _young_gen_sizer->max_desired_young_length();
 535 }
 536 
 537 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
 538   if (rs_lengths == (size_t) -1) {
 539     // if it's set to the default value (-1), we should predict it;
 540     // otherwise, use the given value.
 541     rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
 542   }
 543 
 544   // Calculate the absolute and desired min bounds.
 545 
 546   // This is how many young regions we already have (currently: the survivors).
 547   uint base_min_length = recorded_survivor_regions();
 548   // This is the absolute minimum young length, which ensures that we
 549   // can allocate one eden region in the worst-case.
 550   uint absolute_min_length = base_min_length + 1;
 551   uint desired_min_length =
 552                      calculate_young_list_desired_min_length(base_min_length);
 553   if (desired_min_length < absolute_min_length) {
 554     desired_min_length = absolute_min_length;
 555   }
 556 
 557   // Calculate the absolute and desired max bounds.
 558 
 559   // We will try our best not to "eat" into the reserve.
 560   uint absolute_max_length = 0;
 561   if (_free_regions_at_end_of_collection > _reserve_regions) {
 562     absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
 563   }
 564   uint desired_max_length = calculate_young_list_desired_max_length();
 565   if (desired_max_length > absolute_max_length) {
 566     desired_max_length = absolute_max_length;
 567   }
 568 
 569   uint young_list_target_length = 0;
 570   if (adaptive_young_list_length()) {
 571     if (gcs_are_young()) {
 572       young_list_target_length =
 573                         calculate_young_list_target_length(rs_lengths,
 574                                                            base_min_length,
 575                                                            desired_min_length,
 576                                                            desired_max_length);
 577       _rs_lengths_prediction = rs_lengths;
 578     } else {
 579       // Don't calculate anything and let the code below bound it to
 580       // the desired_min_length, i.e., do the next GC as soon as
 581       // possible to maximize how many old regions we can add to it.
 582     }
 583   } else {
 584     // The user asked for a fixed young gen so we'll fix the young gen
 585     // whether the next GC is young or mixed.
 586     young_list_target_length = _young_list_fixed_length;
 587   }
 588 
 589   // Make sure we don't go over the desired max length, nor under the
 590   // desired min length. In case they clash, desired_min_length wins
 591   // which is why that test is second.
 592   if (young_list_target_length > desired_max_length) {
 593     young_list_target_length = desired_max_length;
 594   }
 595   if (young_list_target_length < desired_min_length) {
 596     young_list_target_length = desired_min_length;
 597   }
 598 
 599   assert(young_list_target_length > recorded_survivor_regions(),
 600          "we should be able to allocate at least one eden region");
 601   assert(young_list_target_length >= absolute_min_length, "post-condition");
 602   _young_list_target_length = young_list_target_length;
 603 
 604   update_max_gc_locker_expansion();
 605 }
 606 
 607 uint
 608 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
 609                                                      uint base_min_length,
 610                                                      uint desired_min_length,
 611                                                      uint desired_max_length) {
 612   assert(adaptive_young_list_length(), "pre-condition");
 613   assert(gcs_are_young(), "only call this for young GCs");
 614 
 615   // In case some edge-condition makes the desired max length too small...
 616   if (desired_max_length <= desired_min_length) {
 617     return desired_min_length;
 618   }
 619 
 620   // We'll adjust min_young_length and max_young_length not to include
 621   // the already allocated young regions (i.e., so they reflect the
 622   // min and max eden regions we'll allocate). The base_min_length
 623   // will be reflected in the predictions by the
 624   // survivor_regions_evac_time prediction.
 625   assert(desired_min_length > base_min_length, "invariant");
 626   uint min_young_length = desired_min_length - base_min_length;
 627   assert(desired_max_length > base_min_length, "invariant");
 628   uint max_young_length = desired_max_length - base_min_length;
 629 
 630   double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
 631   double survivor_regions_evac_time = predict_survivor_regions_evac_time();
 632   size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
 633   size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
 634   size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
 635   double base_time_ms =
 636     predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
 637     survivor_regions_evac_time;
 638   uint available_free_regions = _free_regions_at_end_of_collection;
 639   uint base_free_regions = 0;
 640   if (available_free_regions > _reserve_regions) {
 641     base_free_regions = available_free_regions - _reserve_regions;
 642   }
 643 
 644   // Here, we will make sure that the shortest young length that
 645   // makes sense fits within the target pause time.
 646 
 647   if (predict_will_fit(min_young_length, base_time_ms,
 648                        base_free_regions, target_pause_time_ms)) {
 649     // The shortest young length will fit into the target pause time;
 650     // we'll now check whether the absolute maximum number of young
 651     // regions will fit in the target pause time. If not, we'll do
 652     // a binary search between min_young_length and max_young_length.
 653     if (predict_will_fit(max_young_length, base_time_ms,
 654                          base_free_regions, target_pause_time_ms)) {
 655       // The maximum young length will fit into the target pause time.
 656       // We are done so set min young length to the maximum length (as
 657       // the result is assumed to be returned in min_young_length).
 658       min_young_length = max_young_length;
 659     } else {
 660       // The maximum possible number of young regions will not fit within
 661       // the target pause time so we'll search for the optimal
 662       // length. The loop invariants are:
 663       //
 664       // min_young_length < max_young_length
 665       // min_young_length is known to fit into the target pause time
 666       // max_young_length is known not to fit into the target pause time
 667       //
 668       // Going into the loop we know the above hold as we've just
 669       // checked them. Every time around the loop we check whether
 670       // the middle value between min_young_length and
 671       // max_young_length fits into the target pause time. If it
 672       // does, it becomes the new min. If it doesn't, it becomes
 673       // the new max. This way we maintain the loop invariants.
 674 
 675       assert(min_young_length < max_young_length, "invariant");
 676       uint diff = (max_young_length - min_young_length) / 2;
 677       while (diff > 0) {
 678         uint young_length = min_young_length + diff;
 679         if (predict_will_fit(young_length, base_time_ms,
 680                              base_free_regions, target_pause_time_ms)) {
 681           min_young_length = young_length;
 682         } else {
 683           max_young_length = young_length;
 684         }
 685         assert(min_young_length <  max_young_length, "invariant");
 686         diff = (max_young_length - min_young_length) / 2;
 687       }
 688       // The results is min_young_length which, according to the
 689       // loop invariants, should fit within the target pause time.
 690 
 691       // These are the post-conditions of the binary search above:
 692       assert(min_young_length < max_young_length,
 693              "otherwise we should have discovered that max_young_length "
 694              "fits into the pause target and not done the binary search");
 695       assert(predict_will_fit(min_young_length, base_time_ms,
 696                               base_free_regions, target_pause_time_ms),
 697              "min_young_length, the result of the binary search, should "
 698              "fit into the pause target");
 699       assert(!predict_will_fit(min_young_length + 1, base_time_ms,
 700                                base_free_regions, target_pause_time_ms),
 701              "min_young_length, the result of the binary search, should be "
 702              "optimal, so no larger length should fit into the pause target");
 703     }
 704   } else {
 705     // Even the minimum length doesn't fit into the pause time
 706     // target, return it as the result nevertheless.
 707   }
 708   return base_min_length + min_young_length;
 709 }
 710 
 711 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
 712   double survivor_regions_evac_time = 0.0;
 713   for (HeapRegion * r = _recorded_survivor_head;
 714        r != NULL && r != _recorded_survivor_tail->get_next_young_region();
 715        r = r->get_next_young_region()) {
 716     survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young());
 717   }
 718   return survivor_regions_evac_time;
 719 }
 720 
 721 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
 722   guarantee( adaptive_young_list_length(), "should not call this otherwise" );
 723 
 724   size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
 725   if (rs_lengths > _rs_lengths_prediction) {
 726     // add 10% to avoid having to recalculate often
 727     size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
 728     update_young_list_target_length(rs_lengths_prediction);
 729   }
 730 }
 731 
 732 
 733 
 734 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
 735                                                bool is_tlab,
 736                                                bool* gc_overhead_limit_was_exceeded) {
 737   guarantee(false, "Not using this policy feature yet.");
 738   return NULL;
 739 }
 740 
 741 // This method controls how a collector handles one or more
 742 // of its generations being fully allocated.
 743 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
 744                                                        bool is_tlab) {
 745   guarantee(false, "Not using this policy feature yet.");
 746   return NULL;
 747 }
 748 
 749 
 750 #ifndef PRODUCT
 751 bool G1CollectorPolicy::verify_young_ages() {
 752   HeapRegion* head = _g1->young_list()->first_region();
 753   return
 754     verify_young_ages(head, _short_lived_surv_rate_group);
 755   // also call verify_young_ages on any additional surv rate groups
 756 }
 757 
 758 bool
 759 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
 760                                      SurvRateGroup *surv_rate_group) {
 761   guarantee( surv_rate_group != NULL, "pre-condition" );
 762 
 763   const char* name = surv_rate_group->name();
 764   bool ret = true;
 765   int prev_age = -1;
 766 
 767   for (HeapRegion* curr = head;
 768        curr != NULL;
 769        curr = curr->get_next_young_region()) {
 770     SurvRateGroup* group = curr->surv_rate_group();
 771     if (group == NULL && !curr->is_survivor()) {
 772       gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
 773       ret = false;
 774     }
 775 
 776     if (surv_rate_group == group) {
 777       int age = curr->age_in_surv_rate_group();
 778 
 779       if (age < 0) {
 780         gclog_or_tty->print_cr("## %s: encountered negative age", name);
 781         ret = false;
 782       }
 783 
 784       if (age <= prev_age) {
 785         gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
 786                                "(%d, %d)", name, age, prev_age);
 787         ret = false;
 788       }
 789       prev_age = age;
 790     }
 791   }
 792 
 793   return ret;
 794 }
 795 #endif // PRODUCT
 796 
 797 void G1CollectorPolicy::record_full_collection_start() {
 798   _full_collection_start_sec = os::elapsedTime();
 799   record_heap_size_info_at_start(true /* full */);
 800   // Release the future to-space so that it is available for compaction into.
 801   _g1->set_full_collection();
 802 }
 803 
 804 void G1CollectorPolicy::record_full_collection_end() {
 805   // Consider this like a collection pause for the purposes of allocation
 806   // since last pause.
 807   double end_sec = os::elapsedTime();
 808   double full_gc_time_sec = end_sec - _full_collection_start_sec;
 809   double full_gc_time_ms = full_gc_time_sec * 1000.0;
 810 
 811   _trace_old_gen_time_data.record_full_collection(full_gc_time_ms);
 812 
 813   update_recent_gc_times(end_sec, full_gc_time_ms);
 814 
 815   _g1->clear_full_collection();
 816 
 817   // "Nuke" the heuristics that control the young/mixed GC
 818   // transitions and make sure we start with young GCs after the Full GC.
 819   set_gcs_are_young(true);
 820   _last_young_gc = false;
 821   clear_initiate_conc_mark_if_possible();
 822   clear_during_initial_mark_pause();
 823   _in_marking_window = false;
 824   _in_marking_window_im = false;
 825 
 826   _short_lived_surv_rate_group->start_adding_regions();
 827   // also call this on any additional surv rate groups
 828 
 829   record_survivor_regions(0, NULL, NULL);
 830 
 831   _free_regions_at_end_of_collection = _g1->num_free_regions();
 832   // Reset survivors SurvRateGroup.
 833   _survivor_surv_rate_group->reset();
 834   update_young_list_target_length();
 835   _collectionSetChooser->clear();
 836 }
 837 
 838 void G1CollectorPolicy::record_stop_world_start() {
 839   _stop_world_start = os::elapsedTime();
 840 }
 841 
 842 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
 843   // We only need to do this here as the policy will only be applied
 844   // to the GC we're about to start. so, no point is calculating this
 845   // every time we calculate / recalculate the target young length.
 846   update_survivors_policy();
 847 
 848   assert(_g1->used() == _g1->recalculate_used(),
 849          err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
 850                  _g1->used(), _g1->recalculate_used()));
 851 
 852   double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
 853   _trace_young_gen_time_data.record_start_collection(s_w_t_ms);
 854   _stop_world_start = 0.0;
 855 
 856   record_heap_size_info_at_start(false /* full */);
 857 
 858   phase_times()->record_cur_collection_start_sec(start_time_sec);
 859   _pending_cards = _g1->pending_card_num();
 860 
 861   _collection_set_bytes_used_before = 0;
 862   _bytes_copied_during_gc = 0;
 863 
 864   _last_gc_was_young = false;
 865 
 866   // do that for any other surv rate groups
 867   _short_lived_surv_rate_group->stop_adding_regions();
 868   _survivors_age_table.clear();
 869 
 870   assert( verify_young_ages(), "region age verification" );
 871 }
 872 
 873 void G1CollectorPolicy::record_concurrent_mark_init_end(double
 874                                                    mark_init_elapsed_time_ms) {
 875   _during_marking = true;
 876   assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
 877   clear_during_initial_mark_pause();
 878   _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
 879 }
 880 
 881 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
 882   _mark_remark_start_sec = os::elapsedTime();
 883   _during_marking = false;
 884 }
 885 
 886 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
 887   double end_time_sec = os::elapsedTime();
 888   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
 889   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
 890   _cur_mark_stop_world_time_ms += elapsed_time_ms;
 891   _prev_collection_pause_end_ms += elapsed_time_ms;
 892 
 893   _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
 894 }
 895 
 896 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
 897   _mark_cleanup_start_sec = os::elapsedTime();
 898 }
 899 
 900 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
 901   _last_young_gc = true;
 902   _in_marking_window = false;
 903 }
 904 
 905 void G1CollectorPolicy::record_concurrent_pause() {
 906   if (_stop_world_start > 0.0) {
 907     double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
 908     _trace_young_gen_time_data.record_yield_time(yield_ms);
 909   }
 910 }
 911 
 912 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
 913   if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
 914     return false;
 915   }
 916 
 917   size_t marking_initiating_used_threshold =
 918     (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
 919   size_t cur_used_bytes = _g1->non_young_capacity_bytes();
 920   size_t alloc_byte_size = alloc_word_size * HeapWordSize;
 921 
 922   if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
 923     if (gcs_are_young() && !_last_young_gc) {
 924       ergo_verbose5(ErgoConcCycles,
 925         "request concurrent cycle initiation",
 926         ergo_format_reason("occupancy higher than threshold")
 927         ergo_format_byte("occupancy")
 928         ergo_format_byte("allocation request")
 929         ergo_format_byte_perc("threshold")
 930         ergo_format_str("source"),
 931         cur_used_bytes,
 932         alloc_byte_size,
 933         marking_initiating_used_threshold,
 934         (double) InitiatingHeapOccupancyPercent,
 935         source);
 936       return true;
 937     } else {
 938       ergo_verbose5(ErgoConcCycles,
 939         "do not request concurrent cycle initiation",
 940         ergo_format_reason("still doing mixed collections")
 941         ergo_format_byte("occupancy")
 942         ergo_format_byte("allocation request")
 943         ergo_format_byte_perc("threshold")
 944         ergo_format_str("source"),
 945         cur_used_bytes,
 946         alloc_byte_size,
 947         marking_initiating_used_threshold,
 948         (double) InitiatingHeapOccupancyPercent,
 949         source);
 950     }
 951   }
 952 
 953   return false;
 954 }
 955 
 956 // Anything below that is considered to be zero
 957 #define MIN_TIMER_GRANULARITY 0.0000001
 958 
 959 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info) {
 960   double end_time_sec = os::elapsedTime();
 961   assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
 962          "otherwise, the subtraction below does not make sense");
 963   size_t rs_size =
 964             _cur_collection_pause_used_regions_at_start - cset_region_length();
 965   size_t cur_used_bytes = _g1->used();
 966   assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
 967   bool last_pause_included_initial_mark = false;
 968   bool update_stats = !_g1->evacuation_failed();
 969 
 970 #ifndef PRODUCT
 971   if (G1YoungSurvRateVerbose) {
 972     gclog_or_tty->cr();
 973     _short_lived_surv_rate_group->print();
 974     // do that for any other surv rate groups too
 975   }
 976 #endif // PRODUCT
 977 
 978   last_pause_included_initial_mark = during_initial_mark_pause();
 979   if (last_pause_included_initial_mark) {
 980     record_concurrent_mark_init_end(0.0);
 981   } else if (need_to_start_conc_mark("end of GC")) {
 982     // Note: this might have already been set, if during the last
 983     // pause we decided to start a cycle but at the beginning of
 984     // this pause we decided to postpone it. That's OK.
 985     set_initiate_conc_mark_if_possible();
 986   }
 987 
 988   _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0,
 989                           end_time_sec, false);
 990 
 991   evacuation_info.set_collectionset_used_before(_collection_set_bytes_used_before);
 992   evacuation_info.set_bytes_copied(_bytes_copied_during_gc);
 993 
 994   if (update_stats) {
 995     _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times());
 996     // this is where we update the allocation rate of the application
 997     double app_time_ms =
 998       (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
 999     if (app_time_ms < MIN_TIMER_GRANULARITY) {
1000       // This usually happens due to the timer not having the required
1001       // granularity. Some Linuxes are the usual culprits.
1002       // We'll just set it to something (arbitrarily) small.
1003       app_time_ms = 1.0;
1004     }
1005     // We maintain the invariant that all objects allocated by mutator
1006     // threads will be allocated out of eden regions. So, we can use
1007     // the eden region number allocated since the previous GC to
1008     // calculate the application's allocate rate. The only exception
1009     // to that is humongous objects that are allocated separately. But
1010     // given that humongous object allocations do not really affect
1011     // either the pause's duration nor when the next pause will take
1012     // place we can safely ignore them here.
1013     uint regions_allocated = eden_cset_region_length();
1014     double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1015     _alloc_rate_ms_seq->add(alloc_rate_ms);
1016 
1017     double interval_ms =
1018       (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1019     update_recent_gc_times(end_time_sec, pause_time_ms);
1020     _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1021     if (recent_avg_pause_time_ratio() < 0.0 ||
1022         (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1023 #ifndef PRODUCT
1024       // Dump info to allow post-facto debugging
1025       gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1026       gclog_or_tty->print_cr("-------------------------------------------");
1027       gclog_or_tty->print_cr("Recent GC Times (ms):");
1028       _recent_gc_times_ms->dump();
1029       gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1030       _recent_prev_end_times_for_all_gcs_sec->dump();
1031       gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1032                              _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1033       // In debug mode, terminate the JVM if the user wants to debug at this point.
1034       assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1035 #endif  // !PRODUCT
1036       // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1037       // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1038       if (_recent_avg_pause_time_ratio < 0.0) {
1039         _recent_avg_pause_time_ratio = 0.0;
1040       } else {
1041         assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1042         _recent_avg_pause_time_ratio = 1.0;
1043       }
1044     }
1045   }
1046 
1047   bool new_in_marking_window = _in_marking_window;
1048   bool new_in_marking_window_im = false;
1049   if (last_pause_included_initial_mark) {
1050     new_in_marking_window = true;
1051     new_in_marking_window_im = true;
1052   }
1053 
1054   if (_last_young_gc) {
1055     // This is supposed to to be the "last young GC" before we start
1056     // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1057 
1058     if (!last_pause_included_initial_mark) {
1059       if (next_gc_should_be_mixed("start mixed GCs",
1060                                   "do not start mixed GCs")) {
1061         set_gcs_are_young(false);
1062       }
1063     } else {
1064       ergo_verbose0(ErgoMixedGCs,
1065                     "do not start mixed GCs",
1066                     ergo_format_reason("concurrent cycle is about to start"));
1067     }
1068     _last_young_gc = false;
1069   }
1070 
1071   if (!_last_gc_was_young) {
1072     // This is a mixed GC. Here we decide whether to continue doing
1073     // mixed GCs or not.
1074 
1075     if (!next_gc_should_be_mixed("continue mixed GCs",
1076                                  "do not continue mixed GCs")) {
1077       set_gcs_are_young(true);
1078     }
1079   }
1080 
1081   _short_lived_surv_rate_group->start_adding_regions();
1082   // Do that for any other surv rate groups
1083 
1084   if (update_stats) {
1085     double cost_per_card_ms = 0.0;
1086     if (_pending_cards > 0) {
1087       cost_per_card_ms = phase_times()->average_last_update_rs_time() / (double) _pending_cards;
1088       _cost_per_card_ms_seq->add(cost_per_card_ms);
1089     }
1090 
1091     size_t cards_scanned = _g1->cards_scanned();
1092 
1093     double cost_per_entry_ms = 0.0;
1094     if (cards_scanned > 10) {
1095       cost_per_entry_ms = phase_times()->average_last_scan_rs_time() / (double) cards_scanned;
1096       if (_last_gc_was_young) {
1097         _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1098       } else {
1099         _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1100       }
1101     }
1102 
1103     if (_max_rs_lengths > 0) {
1104       double cards_per_entry_ratio =
1105         (double) cards_scanned / (double) _max_rs_lengths;
1106       if (_last_gc_was_young) {
1107         _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1108       } else {
1109         _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1110       }
1111     }
1112 
1113     // This is defensive. For a while _max_rs_lengths could get
1114     // smaller than _recorded_rs_lengths which was causing
1115     // rs_length_diff to get very large and mess up the RSet length
1116     // predictions. The reason was unsafe concurrent updates to the
1117     // _inc_cset_recorded_rs_lengths field which the code below guards
1118     // against (see CR 7118202). This bug has now been fixed (see CR
1119     // 7119027). However, I'm still worried that
1120     // _inc_cset_recorded_rs_lengths might still end up somewhat
1121     // inaccurate. The concurrent refinement thread calculates an
1122     // RSet's length concurrently with other CR threads updating it
1123     // which might cause it to calculate the length incorrectly (if,
1124     // say, it's in mid-coarsening). So I'll leave in the defensive
1125     // conditional below just in case.
1126     size_t rs_length_diff = 0;
1127     if (_max_rs_lengths > _recorded_rs_lengths) {
1128       rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1129     }
1130     _rs_length_diff_seq->add((double) rs_length_diff);
1131 
1132     size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1133     size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1134     double cost_per_byte_ms = 0.0;
1135 
1136     if (copied_bytes > 0) {
1137       cost_per_byte_ms = phase_times()->average_last_obj_copy_time() / (double) copied_bytes;
1138       if (_in_marking_window) {
1139         _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1140       } else {
1141         _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1142       }
1143     }
1144 
1145     double all_other_time_ms = pause_time_ms -
1146       (phase_times()->average_last_update_rs_time() + phase_times()->average_last_scan_rs_time()
1147       + phase_times()->average_last_obj_copy_time() + phase_times()->average_last_termination_time());
1148 
1149     double young_other_time_ms = 0.0;
1150     if (young_cset_region_length() > 0) {
1151       young_other_time_ms =
1152         phase_times()->young_cset_choice_time_ms() +
1153         phase_times()->young_free_cset_time_ms();
1154       _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1155                                           (double) young_cset_region_length());
1156     }
1157     double non_young_other_time_ms = 0.0;
1158     if (old_cset_region_length() > 0) {
1159       non_young_other_time_ms =
1160         phase_times()->non_young_cset_choice_time_ms() +
1161         phase_times()->non_young_free_cset_time_ms();
1162 
1163       _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1164                                             (double) old_cset_region_length());
1165     }
1166 
1167     double constant_other_time_ms = all_other_time_ms -
1168       (young_other_time_ms + non_young_other_time_ms);
1169     _constant_other_time_ms_seq->add(constant_other_time_ms);
1170 
1171     double survival_ratio = 0.0;
1172     if (_collection_set_bytes_used_before > 0) {
1173       survival_ratio = (double) _bytes_copied_during_gc /
1174                                    (double) _collection_set_bytes_used_before;
1175     }
1176 
1177     _pending_cards_seq->add((double) _pending_cards);
1178     _rs_lengths_seq->add((double) _max_rs_lengths);
1179   }
1180 
1181   _in_marking_window = new_in_marking_window;
1182   _in_marking_window_im = new_in_marking_window_im;
1183   _free_regions_at_end_of_collection = _g1->num_free_regions();
1184   update_young_list_target_length();
1185 
1186   // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1187   double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1188   adjust_concurrent_refinement(phase_times()->average_last_update_rs_time(),
1189                                phase_times()->sum_last_update_rs_processed_buffers(), update_rs_time_goal_ms);
1190 
1191   _collectionSetChooser->verify();
1192 }
1193 
1194 #define EXT_SIZE_FORMAT "%.1f%s"
1195 #define EXT_SIZE_PARAMS(bytes)                                  \
1196   byte_size_in_proper_unit((double)(bytes)),                    \
1197   proper_unit_for_byte_size((bytes))
1198 
1199 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1200   YoungList* young_list = _g1->young_list();
1201   _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1202   _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1203   _heap_capacity_bytes_before_gc = _g1->capacity();
1204   _heap_used_bytes_before_gc = _g1->used();
1205   _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1206 
1207   _eden_capacity_bytes_before_gc =
1208          (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1209 
1210   if (full) {
1211     _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1212   }
1213 }
1214 
1215 void G1CollectorPolicy::print_heap_transition() {
1216   _g1->print_size_transition(gclog_or_tty,
1217                              _heap_used_bytes_before_gc,
1218                              _g1->used(),
1219                              _g1->capacity());
1220 }
1221 
1222 void G1CollectorPolicy::print_detailed_heap_transition(bool full) {
1223   YoungList* young_list = _g1->young_list();
1224 
1225   size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1226   size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1227   size_t heap_used_bytes_after_gc = _g1->used();
1228 
1229   size_t heap_capacity_bytes_after_gc = _g1->capacity();
1230   size_t eden_capacity_bytes_after_gc =
1231     (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1232 
1233   gclog_or_tty->print(
1234     "   [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
1235     "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1236     "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
1237     EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
1238     EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1239     EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1240     EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1241     EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1242     EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1243     EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1244     EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1245     EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1246     EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1247     EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1248 
1249   if (full) {
1250     MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1251   }
1252 
1253   gclog_or_tty->cr();
1254 }
1255 
1256 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1257                                                      double update_rs_processed_buffers,
1258                                                      double goal_ms) {
1259   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1260   ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1261 
1262   if (G1UseAdaptiveConcRefinement) {
1263     const int k_gy = 3, k_gr = 6;
1264     const double inc_k = 1.1, dec_k = 0.9;
1265 
1266     int g = cg1r->green_zone();
1267     if (update_rs_time > goal_ms) {
1268       g = (int)(g * dec_k);  // Can become 0, that's OK. That would mean a mutator-only processing.
1269     } else {
1270       if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1271         g = (int)MAX2(g * inc_k, g + 1.0);
1272       }
1273     }
1274     // Change the refinement threads params
1275     cg1r->set_green_zone(g);
1276     cg1r->set_yellow_zone(g * k_gy);
1277     cg1r->set_red_zone(g * k_gr);
1278     cg1r->reinitialize_threads();
1279 
1280     int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1281     int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1282                                     cg1r->yellow_zone());
1283     // Change the barrier params
1284     dcqs.set_process_completed_threshold(processing_threshold);
1285     dcqs.set_max_completed_queue(cg1r->red_zone());
1286   }
1287 
1288   int curr_queue_size = dcqs.completed_buffers_num();
1289   if (curr_queue_size >= cg1r->yellow_zone()) {
1290     dcqs.set_completed_queue_padding(curr_queue_size);
1291   } else {
1292     dcqs.set_completed_queue_padding(0);
1293   }
1294   dcqs.notify_if_necessary();
1295 }
1296 
1297 double
1298 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1299                                                 size_t scanned_cards) {
1300   return
1301     predict_rs_update_time_ms(pending_cards) +
1302     predict_rs_scan_time_ms(scanned_cards) +
1303     predict_constant_other_time_ms();
1304 }
1305 
1306 double
1307 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1308   size_t rs_length = predict_rs_length_diff();
1309   size_t card_num;
1310   if (gcs_are_young()) {
1311     card_num = predict_young_card_num(rs_length);
1312   } else {
1313     card_num = predict_non_young_card_num(rs_length);
1314   }
1315   return predict_base_elapsed_time_ms(pending_cards, card_num);
1316 }
1317 
1318 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1319   size_t bytes_to_copy;
1320   if (hr->is_marked())
1321     bytes_to_copy = hr->max_live_bytes();
1322   else {
1323     assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1324     int age = hr->age_in_surv_rate_group();
1325     double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1326     bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1327   }
1328   return bytes_to_copy;
1329 }
1330 
1331 double
1332 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1333                                                   bool for_young_gc) {
1334   size_t rs_length = hr->rem_set()->occupied();
1335   size_t card_num;
1336 
1337   // Predicting the number of cards is based on which type of GC
1338   // we're predicting for.
1339   if (for_young_gc) {
1340     card_num = predict_young_card_num(rs_length);
1341   } else {
1342     card_num = predict_non_young_card_num(rs_length);
1343   }
1344   size_t bytes_to_copy = predict_bytes_to_copy(hr);
1345 
1346   double region_elapsed_time_ms =
1347     predict_rs_scan_time_ms(card_num) +
1348     predict_object_copy_time_ms(bytes_to_copy);
1349 
1350   // The prediction of the "other" time for this region is based
1351   // upon the region type and NOT the GC type.
1352   if (hr->is_young()) {
1353     region_elapsed_time_ms += predict_young_other_time_ms(1);
1354   } else {
1355     region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1356   }
1357   return region_elapsed_time_ms;
1358 }
1359 
1360 void
1361 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1362                                             uint survivor_cset_region_length) {
1363   _eden_cset_region_length     = eden_cset_region_length;
1364   _survivor_cset_region_length = survivor_cset_region_length;
1365   _old_cset_region_length      = 0;
1366 }
1367 
1368 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1369   _recorded_rs_lengths = rs_lengths;
1370 }
1371 
1372 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1373                                                double elapsed_ms) {
1374   _recent_gc_times_ms->add(elapsed_ms);
1375   _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1376   _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1377 }
1378 
1379 size_t G1CollectorPolicy::expansion_amount() {
1380   double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1381   double threshold = _gc_overhead_perc;
1382   if (recent_gc_overhead > threshold) {
1383     // We will double the existing space, or take
1384     // G1ExpandByPercentOfAvailable % of the available expansion
1385     // space, whichever is smaller, bounded below by a minimum
1386     // expansion (unless that's all that's left.)
1387     const size_t min_expand_bytes = 1*M;
1388     size_t reserved_bytes = _g1->max_capacity();
1389     size_t committed_bytes = _g1->capacity();
1390     size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1391     size_t expand_bytes;
1392     size_t expand_bytes_via_pct =
1393       uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1394     expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1395     expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1396     expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1397 
1398     ergo_verbose5(ErgoHeapSizing,
1399                   "attempt heap expansion",
1400                   ergo_format_reason("recent GC overhead higher than "
1401                                      "threshold after GC")
1402                   ergo_format_perc("recent GC overhead")
1403                   ergo_format_perc("threshold")
1404                   ergo_format_byte("uncommitted")
1405                   ergo_format_byte_perc("calculated expansion amount"),
1406                   recent_gc_overhead, threshold,
1407                   uncommitted_bytes,
1408                   expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1409 
1410     return expand_bytes;
1411   } else {
1412     return 0;
1413   }
1414 }
1415 
1416 void G1CollectorPolicy::print_tracing_info() const {
1417   _trace_young_gen_time_data.print();
1418   _trace_old_gen_time_data.print();
1419 }
1420 
1421 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1422 #ifndef PRODUCT
1423   _short_lived_surv_rate_group->print_surv_rate_summary();
1424   // add this call for any other surv rate groups
1425 #endif // PRODUCT
1426 }
1427 
1428 bool G1CollectorPolicy::is_young_list_full() {
1429   uint young_list_length = _g1->young_list()->length();
1430   uint young_list_target_length = _young_list_target_length;
1431   return young_list_length >= young_list_target_length;
1432 }
1433 
1434 bool G1CollectorPolicy::can_expand_young_list() {
1435   uint young_list_length = _g1->young_list()->length();
1436   uint young_list_max_length = _young_list_max_length;
1437   return young_list_length < young_list_max_length;
1438 }
1439 
1440 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1441   uint expansion_region_num = 0;
1442   if (GCLockerEdenExpansionPercent > 0) {
1443     double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1444     double expansion_region_num_d = perc * (double) _young_list_target_length;
1445     // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1446     // less than 1.0) we'll get 1.
1447     expansion_region_num = (uint) ceil(expansion_region_num_d);
1448   } else {
1449     assert(expansion_region_num == 0, "sanity");
1450   }
1451   _young_list_max_length = _young_list_target_length + expansion_region_num;
1452   assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1453 }
1454 
1455 // Calculates survivor space parameters.
1456 void G1CollectorPolicy::update_survivors_policy() {
1457   double max_survivor_regions_d =
1458                  (double) _young_list_target_length / (double) SurvivorRatio;
1459   // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1460   // smaller than 1.0) we'll get 1.
1461   _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1462 
1463   _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1464         HeapRegion::GrainWords * _max_survivor_regions);
1465 }
1466 
1467 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
1468                                                      GCCause::Cause gc_cause) {
1469   bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1470   if (!during_cycle) {
1471     ergo_verbose1(ErgoConcCycles,
1472                   "request concurrent cycle initiation",
1473                   ergo_format_reason("requested by GC cause")
1474                   ergo_format_str("GC cause"),
1475                   GCCause::to_string(gc_cause));
1476     set_initiate_conc_mark_if_possible();
1477     return true;
1478   } else {
1479     ergo_verbose1(ErgoConcCycles,
1480                   "do not request concurrent cycle initiation",
1481                   ergo_format_reason("concurrent cycle already in progress")
1482                   ergo_format_str("GC cause"),
1483                   GCCause::to_string(gc_cause));
1484     return false;
1485   }
1486 }
1487 
1488 void
1489 G1CollectorPolicy::decide_on_conc_mark_initiation() {
1490   // We are about to decide on whether this pause will be an
1491   // initial-mark pause.
1492 
1493   // First, during_initial_mark_pause() should not be already set. We
1494   // will set it here if we have to. However, it should be cleared by
1495   // the end of the pause (it's only set for the duration of an
1496   // initial-mark pause).
1497   assert(!during_initial_mark_pause(), "pre-condition");
1498 
1499   if (initiate_conc_mark_if_possible()) {
1500     // We had noticed on a previous pause that the heap occupancy has
1501     // gone over the initiating threshold and we should start a
1502     // concurrent marking cycle. So we might initiate one.
1503 
1504     bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1505     if (!during_cycle) {
1506       // The concurrent marking thread is not "during a cycle", i.e.,
1507       // it has completed the last one. So we can go ahead and
1508       // initiate a new cycle.
1509 
1510       set_during_initial_mark_pause();
1511       // We do not allow mixed GCs during marking.
1512       if (!gcs_are_young()) {
1513         set_gcs_are_young(true);
1514         ergo_verbose0(ErgoMixedGCs,
1515                       "end mixed GCs",
1516                       ergo_format_reason("concurrent cycle is about to start"));
1517       }
1518 
1519       // And we can now clear initiate_conc_mark_if_possible() as
1520       // we've already acted on it.
1521       clear_initiate_conc_mark_if_possible();
1522 
1523       ergo_verbose0(ErgoConcCycles,
1524                   "initiate concurrent cycle",
1525                   ergo_format_reason("concurrent cycle initiation requested"));
1526     } else {
1527       // The concurrent marking thread is still finishing up the
1528       // previous cycle. If we start one right now the two cycles
1529       // overlap. In particular, the concurrent marking thread might
1530       // be in the process of clearing the next marking bitmap (which
1531       // we will use for the next cycle if we start one). Starting a
1532       // cycle now will be bad given that parts of the marking
1533       // information might get cleared by the marking thread. And we
1534       // cannot wait for the marking thread to finish the cycle as it
1535       // periodically yields while clearing the next marking bitmap
1536       // and, if it's in a yield point, it's waiting for us to
1537       // finish. So, at this point we will not start a cycle and we'll
1538       // let the concurrent marking thread complete the last one.
1539       ergo_verbose0(ErgoConcCycles,
1540                     "do not initiate concurrent cycle",
1541                     ergo_format_reason("concurrent cycle already in progress"));
1542     }
1543   }
1544 }
1545 
1546 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1547   G1CollectedHeap* _g1h;
1548   CSetChooserParUpdater _cset_updater;
1549 
1550 public:
1551   ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1552                            uint chunk_size) :
1553     _g1h(G1CollectedHeap::heap()),
1554     _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1555 
1556   bool doHeapRegion(HeapRegion* r) {
1557     // Do we have any marking information for this region?
1558     if (r->is_marked()) {
1559       // We will skip any region that's currently used as an old GC
1560       // alloc region (we should not consider those for collection
1561       // before we fill them up).
1562       if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1563         _cset_updater.add_region(r);
1564       }
1565     }
1566     return false;
1567   }
1568 };
1569 
1570 class ParKnownGarbageTask: public AbstractGangTask {
1571   CollectionSetChooser* _hrSorted;
1572   uint _chunk_size;
1573   G1CollectedHeap* _g1;
1574   HeapRegionClaimer _hrclaimer;
1575 
1576 public:
1577   ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
1578       AbstractGangTask("ParKnownGarbageTask"),
1579       _hrSorted(hrSorted), _chunk_size(chunk_size),
1580       _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
1581 
1582   void work(uint worker_id) {
1583     ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1584     _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
1585   }
1586 };
1587 
1588 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) {
1589   assert(n_workers > 0, "Active gc workers should be greater than 0");
1590   const uint overpartition_factor = 4;
1591   const uint min_chunk_size = MAX2(n_regions / n_workers, 1U);
1592   return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size);
1593 }
1594 
1595 void
1596 G1CollectorPolicy::record_concurrent_mark_cleanup_end(uint n_workers) {
1597   _collectionSetChooser->clear();
1598 
1599   uint n_regions = _g1->num_regions();
1600   uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions);
1601   _collectionSetChooser->prepare_for_par_region_addition(n_regions, chunk_size);
1602   ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers);
1603   _g1->workers()->run_task(&par_known_garbage_task);
1604 
1605   _collectionSetChooser->sort_regions();
1606 
1607   double end_sec = os::elapsedTime();
1608   double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1609   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1610   _cur_mark_stop_world_time_ms += elapsed_time_ms;
1611   _prev_collection_pause_end_ms += elapsed_time_ms;
1612   _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true);
1613 }
1614 
1615 // Add the heap region at the head of the non-incremental collection set
1616 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1617   assert(_inc_cset_build_state == Active, "Precondition");
1618   assert(hr->is_old(), "the region should be old");
1619 
1620   assert(!hr->in_collection_set(), "should not already be in the CSet");
1621   hr->set_in_collection_set(true);
1622   hr->set_next_in_collection_set(_collection_set);
1623   _collection_set = hr;
1624   _collection_set_bytes_used_before += hr->used();
1625   _g1->register_old_region_with_in_cset_fast_test(hr);
1626   size_t rs_length = hr->rem_set()->occupied();
1627   _recorded_rs_lengths += rs_length;
1628   _old_cset_region_length += 1;
1629 }
1630 
1631 // Initialize the per-collection-set information
1632 void G1CollectorPolicy::start_incremental_cset_building() {
1633   assert(_inc_cset_build_state == Inactive, "Precondition");
1634 
1635   _inc_cset_head = NULL;
1636   _inc_cset_tail = NULL;
1637   _inc_cset_bytes_used_before = 0;
1638 
1639   _inc_cset_max_finger = 0;
1640   _inc_cset_recorded_rs_lengths = 0;
1641   _inc_cset_recorded_rs_lengths_diffs = 0;
1642   _inc_cset_predicted_elapsed_time_ms = 0.0;
1643   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1644   _inc_cset_build_state = Active;
1645 }
1646 
1647 void G1CollectorPolicy::finalize_incremental_cset_building() {
1648   assert(_inc_cset_build_state == Active, "Precondition");
1649   assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1650 
1651   // The two "main" fields, _inc_cset_recorded_rs_lengths and
1652   // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1653   // that adds a new region to the CSet. Further updates by the
1654   // concurrent refinement thread that samples the young RSet lengths
1655   // are accumulated in the *_diffs fields. Here we add the diffs to
1656   // the "main" fields.
1657 
1658   if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1659     _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1660   } else {
1661     // This is defensive. The diff should in theory be always positive
1662     // as RSets can only grow between GCs. However, given that we
1663     // sample their size concurrently with other threads updating them
1664     // it's possible that we might get the wrong size back, which
1665     // could make the calculations somewhat inaccurate.
1666     size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1667     if (_inc_cset_recorded_rs_lengths >= diffs) {
1668       _inc_cset_recorded_rs_lengths -= diffs;
1669     } else {
1670       _inc_cset_recorded_rs_lengths = 0;
1671     }
1672   }
1673   _inc_cset_predicted_elapsed_time_ms +=
1674                                      _inc_cset_predicted_elapsed_time_ms_diffs;
1675 
1676   _inc_cset_recorded_rs_lengths_diffs = 0;
1677   _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1678 }
1679 
1680 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1681   // This routine is used when:
1682   // * adding survivor regions to the incremental cset at the end of an
1683   //   evacuation pause,
1684   // * adding the current allocation region to the incremental cset
1685   //   when it is retired, and
1686   // * updating existing policy information for a region in the
1687   //   incremental cset via young list RSet sampling.
1688   // Therefore this routine may be called at a safepoint by the
1689   // VM thread, or in-between safepoints by mutator threads (when
1690   // retiring the current allocation region) or a concurrent
1691   // refine thread (RSet sampling).
1692 
1693   double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1694   size_t used_bytes = hr->used();
1695   _inc_cset_recorded_rs_lengths += rs_length;
1696   _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1697   _inc_cset_bytes_used_before += used_bytes;
1698 
1699   // Cache the values we have added to the aggregated information
1700   // in the heap region in case we have to remove this region from
1701   // the incremental collection set, or it is updated by the
1702   // rset sampling code
1703   hr->set_recorded_rs_length(rs_length);
1704   hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1705 }
1706 
1707 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1708                                                      size_t new_rs_length) {
1709   // Update the CSet information that is dependent on the new RS length
1710   assert(hr->is_young(), "Precondition");
1711   assert(!SafepointSynchronize::is_at_safepoint(),
1712                                                "should not be at a safepoint");
1713 
1714   // We could have updated _inc_cset_recorded_rs_lengths and
1715   // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1716   // that atomically, as this code is executed by a concurrent
1717   // refinement thread, potentially concurrently with a mutator thread
1718   // allocating a new region and also updating the same fields. To
1719   // avoid the atomic operations we accumulate these updates on two
1720   // separate fields (*_diffs) and we'll just add them to the "main"
1721   // fields at the start of a GC.
1722 
1723   ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1724   ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1725   _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1726 
1727   double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1728   double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1729   double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1730   _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1731 
1732   hr->set_recorded_rs_length(new_rs_length);
1733   hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1734 }
1735 
1736 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1737   assert(hr->is_young(), "invariant");
1738   assert(hr->young_index_in_cset() > -1, "should have already been set");
1739   assert(_inc_cset_build_state == Active, "Precondition");
1740 
1741   // We need to clear and set the cached recorded/cached collection set
1742   // information in the heap region here (before the region gets added
1743   // to the collection set). An individual heap region's cached values
1744   // are calculated, aggregated with the policy collection set info,
1745   // and cached in the heap region here (initially) and (subsequently)
1746   // by the Young List sampling code.
1747 
1748   size_t rs_length = hr->rem_set()->occupied();
1749   add_to_incremental_cset_info(hr, rs_length);
1750 
1751   HeapWord* hr_end = hr->end();
1752   _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1753 
1754   assert(!hr->in_collection_set(), "invariant");
1755   hr->set_in_collection_set(true);
1756   assert( hr->next_in_collection_set() == NULL, "invariant");
1757 
1758   _g1->register_young_region_with_in_cset_fast_test(hr);
1759 }
1760 
1761 // Add the region at the RHS of the incremental cset
1762 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1763   // We should only ever be appending survivors at the end of a pause
1764   assert(hr->is_survivor(), "Logic");
1765 
1766   // Do the 'common' stuff
1767   add_region_to_incremental_cset_common(hr);
1768 
1769   // Now add the region at the right hand side
1770   if (_inc_cset_tail == NULL) {
1771     assert(_inc_cset_head == NULL, "invariant");
1772     _inc_cset_head = hr;
1773   } else {
1774     _inc_cset_tail->set_next_in_collection_set(hr);
1775   }
1776   _inc_cset_tail = hr;
1777 }
1778 
1779 // Add the region to the LHS of the incremental cset
1780 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1781   // Survivors should be added to the RHS at the end of a pause
1782   assert(hr->is_eden(), "Logic");
1783 
1784   // Do the 'common' stuff
1785   add_region_to_incremental_cset_common(hr);
1786 
1787   // Add the region at the left hand side
1788   hr->set_next_in_collection_set(_inc_cset_head);
1789   if (_inc_cset_head == NULL) {
1790     assert(_inc_cset_tail == NULL, "Invariant");
1791     _inc_cset_tail = hr;
1792   }
1793   _inc_cset_head = hr;
1794 }
1795 
1796 #ifndef PRODUCT
1797 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1798   assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1799 
1800   st->print_cr("\nCollection_set:");
1801   HeapRegion* csr = list_head;
1802   while (csr != NULL) {
1803     HeapRegion* next = csr->next_in_collection_set();
1804     assert(csr->in_collection_set(), "bad CS");
1805     st->print_cr("  "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
1806                  HR_FORMAT_PARAMS(csr),
1807                  csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(),
1808                  csr->age_in_surv_rate_group_cond());
1809     csr = next;
1810   }
1811 }
1812 #endif // !PRODUCT
1813 
1814 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) {
1815   // Returns the given amount of reclaimable bytes (that represents
1816   // the amount of reclaimable space still to be collected) as a
1817   // percentage of the current heap capacity.
1818   size_t capacity_bytes = _g1->capacity();
1819   return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1820 }
1821 
1822 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1823                                                 const char* false_action_str) {
1824   CollectionSetChooser* cset_chooser = _collectionSetChooser;
1825   if (cset_chooser->is_empty()) {
1826     ergo_verbose0(ErgoMixedGCs,
1827                   false_action_str,
1828                   ergo_format_reason("candidate old regions not available"));
1829     return false;
1830   }
1831 
1832   // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1833   size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1834   double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1835   double threshold = (double) G1HeapWastePercent;
1836   if (reclaimable_perc <= threshold) {
1837     ergo_verbose4(ErgoMixedGCs,
1838               false_action_str,
1839               ergo_format_reason("reclaimable percentage not over threshold")
1840               ergo_format_region("candidate old regions")
1841               ergo_format_byte_perc("reclaimable")
1842               ergo_format_perc("threshold"),
1843               cset_chooser->remaining_regions(),
1844               reclaimable_bytes,
1845               reclaimable_perc, threshold);
1846     return false;
1847   }
1848 
1849   ergo_verbose4(ErgoMixedGCs,
1850                 true_action_str,
1851                 ergo_format_reason("candidate old regions available")
1852                 ergo_format_region("candidate old regions")
1853                 ergo_format_byte_perc("reclaimable")
1854                 ergo_format_perc("threshold"),
1855                 cset_chooser->remaining_regions(),
1856                 reclaimable_bytes,
1857                 reclaimable_perc, threshold);
1858   return true;
1859 }
1860 
1861 uint G1CollectorPolicy::calc_min_old_cset_length() {
1862   // The min old CSet region bound is based on the maximum desired
1863   // number of mixed GCs after a cycle. I.e., even if some old regions
1864   // look expensive, we should add them to the CSet anyway to make
1865   // sure we go through the available old regions in no more than the
1866   // maximum desired number of mixed GCs.
1867   //
1868   // The calculation is based on the number of marked regions we added
1869   // to the CSet chooser in the first place, not how many remain, so
1870   // that the result is the same during all mixed GCs that follow a cycle.
1871 
1872   const size_t region_num = (size_t) _collectionSetChooser->length();
1873   const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
1874   size_t result = region_num / gc_num;
1875   // emulate ceiling
1876   if (result * gc_num < region_num) {
1877     result += 1;
1878   }
1879   return (uint) result;
1880 }
1881 
1882 uint G1CollectorPolicy::calc_max_old_cset_length() {
1883   // The max old CSet region bound is based on the threshold expressed
1884   // as a percentage of the heap size. I.e., it should bound the
1885   // number of old regions added to the CSet irrespective of how many
1886   // of them are available.
1887 
1888   G1CollectedHeap* g1h = G1CollectedHeap::heap();
1889   const size_t region_num = g1h->num_regions();
1890   const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
1891   size_t result = region_num * perc / 100;
1892   // emulate ceiling
1893   if (100 * result < region_num * perc) {
1894     result += 1;
1895   }
1896   return (uint) result;
1897 }
1898 
1899 
1900 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info) {
1901   double young_start_time_sec = os::elapsedTime();
1902 
1903   YoungList* young_list = _g1->young_list();
1904   finalize_incremental_cset_building();
1905 
1906   guarantee(target_pause_time_ms > 0.0,
1907             err_msg("target_pause_time_ms = %1.6lf should be positive",
1908                     target_pause_time_ms));
1909   guarantee(_collection_set == NULL, "Precondition");
1910 
1911   double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
1912   double predicted_pause_time_ms = base_time_ms;
1913   double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
1914 
1915   ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
1916                 "start choosing CSet",
1917                 ergo_format_size("_pending_cards")
1918                 ergo_format_ms("predicted base time")
1919                 ergo_format_ms("remaining time")
1920                 ergo_format_ms("target pause time"),
1921                 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
1922 
1923   _last_gc_was_young = gcs_are_young() ? true : false;
1924 
1925   if (_last_gc_was_young) {
1926     _trace_young_gen_time_data.increment_young_collection_count();
1927   } else {
1928     _trace_young_gen_time_data.increment_mixed_collection_count();
1929   }
1930 
1931   // The young list is laid with the survivor regions from the previous
1932   // pause are appended to the RHS of the young list, i.e.
1933   //   [Newly Young Regions ++ Survivors from last pause].
1934 
1935   uint survivor_region_length = young_list->survivor_length();
1936   uint eden_region_length = young_list->length() - survivor_region_length;
1937   init_cset_region_lengths(eden_region_length, survivor_region_length);
1938 
1939   HeapRegion* hr = young_list->first_survivor_region();
1940   while (hr != NULL) {
1941     assert(hr->is_survivor(), "badly formed young list");
1942     // There is a convention that all the young regions in the CSet
1943     // are tagged as "eden", so we do this for the survivors here. We
1944     // use the special set_eden_pre_gc() as it doesn't check that the
1945     // region is free (which is not the case here).
1946     hr->set_eden_pre_gc();
1947     hr = hr->get_next_young_region();
1948   }
1949 
1950   // Clear the fields that point to the survivor list - they are all young now.
1951   young_list->clear_survivors();
1952 
1953   _collection_set = _inc_cset_head;
1954   _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
1955   time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
1956   predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
1957 
1958   ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
1959                 "add young regions to CSet",
1960                 ergo_format_region("eden")
1961                 ergo_format_region("survivors")
1962                 ergo_format_ms("predicted young region time"),
1963                 eden_region_length, survivor_region_length,
1964                 _inc_cset_predicted_elapsed_time_ms);
1965 
1966   // The number of recorded young regions is the incremental
1967   // collection set's current size
1968   set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
1969 
1970   double young_end_time_sec = os::elapsedTime();
1971   phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
1972 
1973   // Set the start of the non-young choice time.
1974   double non_young_start_time_sec = young_end_time_sec;
1975 
1976   if (!gcs_are_young()) {
1977     CollectionSetChooser* cset_chooser = _collectionSetChooser;
1978     cset_chooser->verify();
1979     const uint min_old_cset_length = calc_min_old_cset_length();
1980     const uint max_old_cset_length = calc_max_old_cset_length();
1981 
1982     uint expensive_region_num = 0;
1983     bool check_time_remaining = adaptive_young_list_length();
1984 
1985     HeapRegion* hr = cset_chooser->peek();
1986     while (hr != NULL) {
1987       if (old_cset_region_length() >= max_old_cset_length) {
1988         // Added maximum number of old regions to the CSet.
1989         ergo_verbose2(ErgoCSetConstruction,
1990                       "finish adding old regions to CSet",
1991                       ergo_format_reason("old CSet region num reached max")
1992                       ergo_format_region("old")
1993                       ergo_format_region("max"),
1994                       old_cset_region_length(), max_old_cset_length);
1995         break;
1996       }
1997 
1998 
1999       // Stop adding regions if the remaining reclaimable space is
2000       // not above G1HeapWastePercent.
2001       size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
2002       double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
2003       double threshold = (double) G1HeapWastePercent;
2004       if (reclaimable_perc <= threshold) {
2005         // We've added enough old regions that the amount of uncollected
2006         // reclaimable space is at or below the waste threshold. Stop
2007         // adding old regions to the CSet.
2008         ergo_verbose5(ErgoCSetConstruction,
2009                       "finish adding old regions to CSet",
2010                       ergo_format_reason("reclaimable percentage not over threshold")
2011                       ergo_format_region("old")
2012                       ergo_format_region("max")
2013                       ergo_format_byte_perc("reclaimable")
2014                       ergo_format_perc("threshold"),
2015                       old_cset_region_length(),
2016                       max_old_cset_length,
2017                       reclaimable_bytes,
2018                       reclaimable_perc, threshold);
2019         break;
2020       }
2021 
2022       double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
2023       if (check_time_remaining) {
2024         if (predicted_time_ms > time_remaining_ms) {
2025           // Too expensive for the current CSet.
2026 
2027           if (old_cset_region_length() >= min_old_cset_length) {
2028             // We have added the minimum number of old regions to the CSet,
2029             // we are done with this CSet.
2030             ergo_verbose4(ErgoCSetConstruction,
2031                           "finish adding old regions to CSet",
2032                           ergo_format_reason("predicted time is too high")
2033                           ergo_format_ms("predicted time")
2034                           ergo_format_ms("remaining time")
2035                           ergo_format_region("old")
2036                           ergo_format_region("min"),
2037                           predicted_time_ms, time_remaining_ms,
2038                           old_cset_region_length(), min_old_cset_length);
2039             break;
2040           }
2041 
2042           // We'll add it anyway given that we haven't reached the
2043           // minimum number of old regions.
2044           expensive_region_num += 1;
2045         }
2046       } else {
2047         if (old_cset_region_length() >= min_old_cset_length) {
2048           // In the non-auto-tuning case, we'll finish adding regions
2049           // to the CSet if we reach the minimum.
2050           ergo_verbose2(ErgoCSetConstruction,
2051                         "finish adding old regions to CSet",
2052                         ergo_format_reason("old CSet region num reached min")
2053                         ergo_format_region("old")
2054                         ergo_format_region("min"),
2055                         old_cset_region_length(), min_old_cset_length);
2056           break;
2057         }
2058       }
2059 
2060       // We will add this region to the CSet.
2061       time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2062       predicted_pause_time_ms += predicted_time_ms;
2063       cset_chooser->remove_and_move_to_next(hr);
2064       _g1->old_set_remove(hr);
2065       add_old_region_to_cset(hr);
2066 
2067       hr = cset_chooser->peek();
2068     }
2069     if (hr == NULL) {
2070       ergo_verbose0(ErgoCSetConstruction,
2071                     "finish adding old regions to CSet",
2072                     ergo_format_reason("candidate old regions not available"));
2073     }
2074 
2075     if (expensive_region_num > 0) {
2076       // We print the information once here at the end, predicated on
2077       // whether we added any apparently expensive regions or not, to
2078       // avoid generating output per region.
2079       ergo_verbose4(ErgoCSetConstruction,
2080                     "added expensive regions to CSet",
2081                     ergo_format_reason("old CSet region num not reached min")
2082                     ergo_format_region("old")
2083                     ergo_format_region("expensive")
2084                     ergo_format_region("min")
2085                     ergo_format_ms("remaining time"),
2086                     old_cset_region_length(),
2087                     expensive_region_num,
2088                     min_old_cset_length,
2089                     time_remaining_ms);
2090     }
2091 
2092     cset_chooser->verify();
2093   }
2094 
2095   stop_incremental_cset_building();
2096 
2097   ergo_verbose5(ErgoCSetConstruction,
2098                 "finish choosing CSet",
2099                 ergo_format_region("eden")
2100                 ergo_format_region("survivors")
2101                 ergo_format_region("old")
2102                 ergo_format_ms("predicted pause time")
2103                 ergo_format_ms("target pause time"),
2104                 eden_region_length, survivor_region_length,
2105                 old_cset_region_length(),
2106                 predicted_pause_time_ms, target_pause_time_ms);
2107 
2108   double non_young_end_time_sec = os::elapsedTime();
2109   phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2110   evacuation_info.set_collectionset_regions(cset_region_length());
2111 }
2112 
2113 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) {
2114   if(TraceYoungGenTime) {
2115     _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2116   }
2117 }
2118 
2119 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) {
2120   if(TraceYoungGenTime) {
2121     _all_yield_times_ms.add(yield_time_ms);
2122   }
2123 }
2124 
2125 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2126   if(TraceYoungGenTime) {
2127     _total.add(pause_time_ms);
2128     _other.add(pause_time_ms - phase_times->accounted_time_ms());
2129     _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2130     _parallel.add(phase_times->cur_collection_par_time_ms());
2131     _ext_root_scan.add(phase_times->average_last_ext_root_scan_time());
2132     _satb_filtering.add(phase_times->average_last_satb_filtering_times_ms());
2133     _update_rs.add(phase_times->average_last_update_rs_time());
2134     _scan_rs.add(phase_times->average_last_scan_rs_time());
2135     _obj_copy.add(phase_times->average_last_obj_copy_time());
2136     _termination.add(phase_times->average_last_termination_time());
2137 
2138     double parallel_known_time = phase_times->average_last_ext_root_scan_time() +
2139       phase_times->average_last_satb_filtering_times_ms() +
2140       phase_times->average_last_update_rs_time() +
2141       phase_times->average_last_scan_rs_time() +
2142       phase_times->average_last_obj_copy_time() +
2143       + phase_times->average_last_termination_time();
2144 
2145     double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2146     _parallel_other.add(parallel_other_time);
2147     _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2148   }
2149 }
2150 
2151 void TraceYoungGenTimeData::increment_young_collection_count() {
2152   if(TraceYoungGenTime) {
2153     ++_young_pause_num;
2154   }
2155 }
2156 
2157 void TraceYoungGenTimeData::increment_mixed_collection_count() {
2158   if(TraceYoungGenTime) {
2159     ++_mixed_pause_num;
2160   }
2161 }
2162 
2163 void TraceYoungGenTimeData::print_summary(const char* str,
2164                                           const NumberSeq* seq) const {
2165   double sum = seq->sum();
2166   gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2167                 str, sum / 1000.0, seq->avg());
2168 }
2169 
2170 void TraceYoungGenTimeData::print_summary_sd(const char* str,
2171                                              const NumberSeq* seq) const {
2172   print_summary(str, seq);
2173   gclog_or_tty->print_cr("%+45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2174                 "(num", seq->num(), seq->sd(), seq->maximum());
2175 }
2176 
2177 void TraceYoungGenTimeData::print() const {
2178   if (!TraceYoungGenTime) {
2179     return;
2180   }
2181 
2182   gclog_or_tty->print_cr("ALL PAUSES");
2183   print_summary_sd("   Total", &_total);
2184   gclog_or_tty->cr();
2185   gclog_or_tty->cr();
2186   gclog_or_tty->print_cr("   Young GC Pauses: %8d", _young_pause_num);
2187   gclog_or_tty->print_cr("   Mixed GC Pauses: %8d", _mixed_pause_num);
2188   gclog_or_tty->cr();
2189 
2190   gclog_or_tty->print_cr("EVACUATION PAUSES");
2191 
2192   if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2193     gclog_or_tty->print_cr("none");
2194   } else {
2195     print_summary_sd("   Evacuation Pauses", &_total);
2196     print_summary("      Root Region Scan Wait", &_root_region_scan_wait);
2197     print_summary("      Parallel Time", &_parallel);
2198     print_summary("         Ext Root Scanning", &_ext_root_scan);
2199     print_summary("         SATB Filtering", &_satb_filtering);
2200     print_summary("         Update RS", &_update_rs);
2201     print_summary("         Scan RS", &_scan_rs);
2202     print_summary("         Object Copy", &_obj_copy);
2203     print_summary("         Termination", &_termination);
2204     print_summary("         Parallel Other", &_parallel_other);
2205     print_summary("      Clear CT", &_clear_ct);
2206     print_summary("      Other", &_other);
2207   }
2208   gclog_or_tty->cr();
2209 
2210   gclog_or_tty->print_cr("MISC");
2211   print_summary_sd("   Stop World", &_all_stop_world_times_ms);
2212   print_summary_sd("   Yields", &_all_yield_times_ms);
2213 }
2214 
2215 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) {
2216   if (TraceOldGenTime) {
2217     _all_full_gc_times.add(full_gc_time_ms);
2218   }
2219 }
2220 
2221 void TraceOldGenTimeData::print() const {
2222   if (!TraceOldGenTime) {
2223     return;
2224   }
2225 
2226   if (_all_full_gc_times.num() > 0) {
2227     gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2228       _all_full_gc_times.num(),
2229       _all_full_gc_times.sum() / 1000.0);
2230     gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2231     gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
2232       _all_full_gc_times.sd(),
2233       _all_full_gc_times.maximum());
2234   }
2235 }