1 /* 2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #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 _sigma(G1ConfidencePercent / 100.0), 143 144 _collection_set(NULL), 145 _collection_set_bytes_used_before(0), 146 147 // Incremental CSet attributes 148 _inc_cset_build_state(Inactive), 149 _inc_cset_head(NULL), 150 _inc_cset_tail(NULL), 151 _inc_cset_bytes_used_before(0), 152 _inc_cset_max_finger(NULL), 153 _inc_cset_recorded_rs_lengths(0), 154 _inc_cset_recorded_rs_lengths_diffs(0), 155 _inc_cset_predicted_elapsed_time_ms(0.0), 156 _inc_cset_predicted_elapsed_time_ms_diffs(0.0), 157 158 // add here any more surv rate groups 159 _recorded_survivor_regions(0), 160 _recorded_survivor_head(NULL), 161 _recorded_survivor_tail(NULL), 162 _survivors_age_table(true), 163 164 _gc_overhead_perc(0.0) { 165 166 // SurvRateGroups below must be initialized after '_sigma' because they 167 // indirectly access '_sigma' through this object passed to their constructor. 168 _short_lived_surv_rate_group = 169 new SurvRateGroup(this, "Short Lived", G1YoungSurvRateNumRegionsSummary); 170 _survivor_surv_rate_group = 171 new SurvRateGroup(this, "Survivor", G1YoungSurvRateNumRegionsSummary); 172 173 // Set up the region size and associated fields. Given that the 174 // policy is created before the heap, we have to set this up here, 175 // so it's done as soon as possible. 176 177 // It would have been natural to pass initial_heap_byte_size() and 178 // max_heap_byte_size() to setup_heap_region_size() but those have 179 // not been set up at this point since they should be aligned with 180 // the region size. So, there is a circular dependency here. We base 181 // the region size on the heap size, but the heap size should be 182 // aligned with the region size. To get around this we use the 183 // unaligned values for the heap. 184 HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize); 185 HeapRegionRemSet::setup_remset_size(); 186 187 G1ErgoVerbose::initialize(); 188 if (PrintAdaptiveSizePolicy) { 189 // Currently, we only use a single switch for all the heuristics. 190 G1ErgoVerbose::set_enabled(true); 191 // Given that we don't currently have a verboseness level 192 // parameter, we'll hardcode this to high. This can be easily 193 // changed in the future. 194 G1ErgoVerbose::set_level(ErgoHigh); 195 } else { 196 G1ErgoVerbose::set_enabled(false); 197 } 198 199 // Verify PLAB sizes 200 const size_t region_size = HeapRegion::GrainWords; 201 if (YoungPLABSize > region_size || OldPLABSize > region_size) { 202 char buffer[128]; 203 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT, 204 OldPLABSize > region_size ? "Old" : "Young", region_size); 205 vm_exit_during_initialization(buffer); 206 } 207 208 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime()); 209 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0; 210 211 _phase_times = new G1GCPhaseTimes(_parallel_gc_threads); 212 213 int index = MIN2(_parallel_gc_threads - 1, 7); 214 215 _rs_length_diff_seq->add(rs_length_diff_defaults[index]); 216 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]); 217 _young_cards_per_entry_ratio_seq->add( 218 young_cards_per_entry_ratio_defaults[index]); 219 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]); 220 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]); 221 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]); 222 _young_other_cost_per_region_ms_seq->add( 223 young_other_cost_per_region_ms_defaults[index]); 224 _non_young_other_cost_per_region_ms_seq->add( 225 non_young_other_cost_per_region_ms_defaults[index]); 226 227 // Below, we might need to calculate the pause time target based on 228 // the pause interval. When we do so we are going to give G1 maximum 229 // flexibility and allow it to do pauses when it needs to. So, we'll 230 // arrange that the pause interval to be pause time target + 1 to 231 // ensure that a) the pause time target is maximized with respect to 232 // the pause interval and b) we maintain the invariant that pause 233 // time target < pause interval. If the user does not want this 234 // maximum flexibility, they will have to set the pause interval 235 // explicitly. 236 237 // First make sure that, if either parameter is set, its value is 238 // reasonable. 239 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) { 240 if (MaxGCPauseMillis < 1) { 241 vm_exit_during_initialization("MaxGCPauseMillis should be " 242 "greater than 0"); 243 } 244 } 245 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { 246 if (GCPauseIntervalMillis < 1) { 247 vm_exit_during_initialization("GCPauseIntervalMillis should be " 248 "greater than 0"); 249 } 250 } 251 252 // Then, if the pause time target parameter was not set, set it to 253 // the default value. 254 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) { 255 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { 256 // The default pause time target in G1 is 200ms 257 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200); 258 } else { 259 // We do not allow the pause interval to be set without the 260 // pause time target 261 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set " 262 "without setting MaxGCPauseMillis"); 263 } 264 } 265 266 // Then, if the interval parameter was not set, set it according to 267 // the pause time target (this will also deal with the case when the 268 // pause time target is the default value). 269 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { 270 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1); 271 } 272 273 // Finally, make sure that the two parameters are consistent. 274 if (MaxGCPauseMillis >= GCPauseIntervalMillis) { 275 char buffer[256]; 276 jio_snprintf(buffer, 256, 277 "MaxGCPauseMillis (%u) should be less than " 278 "GCPauseIntervalMillis (%u)", 279 MaxGCPauseMillis, GCPauseIntervalMillis); 280 vm_exit_during_initialization(buffer); 281 } 282 283 double max_gc_time = (double) MaxGCPauseMillis / 1000.0; 284 double time_slice = (double) GCPauseIntervalMillis / 1000.0; 285 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time); 286 287 // start conservatively (around 50ms is about right) 288 _concurrent_mark_remark_times_ms->add(0.05); 289 _concurrent_mark_cleanup_times_ms->add(0.20); 290 _tenuring_threshold = MaxTenuringThreshold; 291 // _max_survivor_regions will be calculated by 292 // update_young_list_target_length() during initialization. 293 _max_survivor_regions = 0; 294 295 assert(GCTimeRatio > 0, 296 "we should have set it to a default value set_g1_gc_flags() " 297 "if a user set it to 0"); 298 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio)); 299 300 uintx reserve_perc = G1ReservePercent; 301 // Put an artificial ceiling on this so that it's not set to a silly value. 302 if (reserve_perc > 50) { 303 reserve_perc = 50; 304 warning("G1ReservePercent is set to a value that is too large, " 305 "it's been updated to %u", reserve_perc); 306 } 307 _reserve_factor = (double) reserve_perc / 100.0; 308 // This will be set when the heap is expanded 309 // for the first time during initialization. 310 _reserve_regions = 0; 311 312 _collectionSetChooser = new CollectionSetChooser(); 313 } 314 315 void G1CollectorPolicy::initialize_alignments() { 316 _space_alignment = HeapRegion::GrainBytes; 317 size_t card_table_alignment = GenRemSet::max_alignment_constraint(); 318 size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size(); 319 _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size); 320 } 321 322 void G1CollectorPolicy::initialize_flags() { 323 if (G1HeapRegionSize != HeapRegion::GrainBytes) { 324 FLAG_SET_ERGO(uintx, G1HeapRegionSize, HeapRegion::GrainBytes); 325 } 326 327 if (SurvivorRatio < 1) { 328 vm_exit_during_initialization("Invalid survivor ratio specified"); 329 } 330 CollectorPolicy::initialize_flags(); 331 _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags 332 } 333 334 void G1CollectorPolicy::post_heap_initialize() { 335 uintx max_regions = G1CollectedHeap::heap()->max_regions(); 336 size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes; 337 if (max_young_size != MaxNewSize) { 338 FLAG_SET_ERGO(uintx, MaxNewSize, max_young_size); 339 } 340 } 341 342 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true), 343 _min_desired_young_length(0), _max_desired_young_length(0) { 344 if (FLAG_IS_CMDLINE(NewRatio)) { 345 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) { 346 warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio"); 347 } else { 348 _sizer_kind = SizerNewRatio; 349 _adaptive_size = false; 350 return; 351 } 352 } 353 354 if (NewSize > MaxNewSize) { 355 if (FLAG_IS_CMDLINE(MaxNewSize)) { 356 warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). " 357 "A new max generation size of " SIZE_FORMAT "k will be used.", 358 NewSize/K, MaxNewSize/K, NewSize/K); 359 } 360 MaxNewSize = NewSize; 361 } 362 363 if (FLAG_IS_CMDLINE(NewSize)) { 364 _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes), 365 1U); 366 if (FLAG_IS_CMDLINE(MaxNewSize)) { 367 _max_desired_young_length = 368 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes), 369 1U); 370 _sizer_kind = SizerMaxAndNewSize; 371 _adaptive_size = _min_desired_young_length == _max_desired_young_length; 372 } else { 373 _sizer_kind = SizerNewSizeOnly; 374 } 375 } else if (FLAG_IS_CMDLINE(MaxNewSize)) { 376 _max_desired_young_length = 377 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes), 378 1U); 379 _sizer_kind = SizerMaxNewSizeOnly; 380 } 381 } 382 383 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) { 384 uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100; 385 return MAX2(1U, default_value); 386 } 387 388 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) { 389 uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100; 390 return MAX2(1U, default_value); 391 } 392 393 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) { 394 assert(number_of_heap_regions > 0, "Heap must be initialized"); 395 396 switch (_sizer_kind) { 397 case SizerDefaults: 398 *min_young_length = calculate_default_min_length(number_of_heap_regions); 399 *max_young_length = calculate_default_max_length(number_of_heap_regions); 400 break; 401 case SizerNewSizeOnly: 402 *max_young_length = calculate_default_max_length(number_of_heap_regions); 403 *max_young_length = MAX2(*min_young_length, *max_young_length); 404 break; 405 case SizerMaxNewSizeOnly: 406 *min_young_length = calculate_default_min_length(number_of_heap_regions); 407 *min_young_length = MIN2(*min_young_length, *max_young_length); 408 break; 409 case SizerMaxAndNewSize: 410 // Do nothing. Values set on the command line, don't update them at runtime. 411 break; 412 case SizerNewRatio: 413 *min_young_length = number_of_heap_regions / (NewRatio + 1); 414 *max_young_length = *min_young_length; 415 break; 416 default: 417 ShouldNotReachHere(); 418 } 419 420 assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values"); 421 } 422 423 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) { 424 // We need to pass the desired values because recalculation may not update these 425 // values in some cases. 426 uint temp = _min_desired_young_length; 427 uint result = _max_desired_young_length; 428 recalculate_min_max_young_length(number_of_heap_regions, &temp, &result); 429 return result; 430 } 431 432 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) { 433 recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length, 434 &_max_desired_young_length); 435 } 436 437 void G1CollectorPolicy::init() { 438 // Set aside an initial future to_space. 439 _g1 = G1CollectedHeap::heap(); 440 441 assert(Heap_lock->owned_by_self(), "Locking discipline."); 442 443 initialize_gc_policy_counters(); 444 445 if (adaptive_young_list_length()) { 446 _young_list_fixed_length = 0; 447 } else { 448 _young_list_fixed_length = _young_gen_sizer->min_desired_young_length(); 449 } 450 _free_regions_at_end_of_collection = _g1->num_free_regions(); 451 update_young_list_target_length(); 452 453 // We may immediately start allocating regions and placing them on the 454 // collection set list. Initialize the per-collection set info 455 start_incremental_cset_building(); 456 } 457 458 // Create the jstat counters for the policy. 459 void G1CollectorPolicy::initialize_gc_policy_counters() { 460 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3); 461 } 462 463 bool G1CollectorPolicy::predict_will_fit(uint young_length, 464 double base_time_ms, 465 uint base_free_regions, 466 double target_pause_time_ms) { 467 if (young_length >= base_free_regions) { 468 // end condition 1: not enough space for the young regions 469 return false; 470 } 471 472 double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1); 473 size_t bytes_to_copy = 474 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes); 475 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy); 476 double young_other_time_ms = predict_young_other_time_ms(young_length); 477 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms; 478 if (pause_time_ms > target_pause_time_ms) { 479 // end condition 2: prediction is over the target pause time 480 return false; 481 } 482 483 size_t free_bytes = 484 (base_free_regions - young_length) * HeapRegion::GrainBytes; 485 if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) { 486 // end condition 3: out-of-space (conservatively!) 487 return false; 488 } 489 490 // success! 491 return true; 492 } 493 494 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) { 495 // re-calculate the necessary reserve 496 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor; 497 // We use ceiling so that if reserve_regions_d is > 0.0 (but 498 // smaller than 1.0) we'll get 1. 499 _reserve_regions = (uint) ceil(reserve_regions_d); 500 501 _young_gen_sizer->heap_size_changed(new_number_of_regions); 502 } 503 504 uint G1CollectorPolicy::calculate_young_list_desired_min_length( 505 uint base_min_length) { 506 uint desired_min_length = 0; 507 if (adaptive_young_list_length()) { 508 if (_alloc_rate_ms_seq->num() > 3) { 509 double now_sec = os::elapsedTime(); 510 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0; 511 double alloc_rate_ms = predict_alloc_rate_ms(); 512 desired_min_length = (uint) ceil(alloc_rate_ms * when_ms); 513 } else { 514 // otherwise we don't have enough info to make the prediction 515 } 516 } 517 desired_min_length += base_min_length; 518 // make sure we don't go below any user-defined minimum bound 519 return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length); 520 } 521 522 uint G1CollectorPolicy::calculate_young_list_desired_max_length() { 523 // Here, we might want to also take into account any additional 524 // constraints (i.e., user-defined minimum bound). Currently, we 525 // effectively don't set this bound. 526 return _young_gen_sizer->max_desired_young_length(); 527 } 528 529 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) { 530 if (rs_lengths == (size_t) -1) { 531 // if it's set to the default value (-1), we should predict it; 532 // otherwise, use the given value. 533 rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq); 534 } 535 536 // Calculate the absolute and desired min bounds. 537 538 // This is how many young regions we already have (currently: the survivors). 539 uint base_min_length = recorded_survivor_regions(); 540 // This is the absolute minimum young length, which ensures that we 541 // can allocate one eden region in the worst-case. 542 uint absolute_min_length = base_min_length + 1; 543 uint desired_min_length = 544 calculate_young_list_desired_min_length(base_min_length); 545 if (desired_min_length < absolute_min_length) { 546 desired_min_length = absolute_min_length; 547 } 548 549 // Calculate the absolute and desired max bounds. 550 551 // We will try our best not to "eat" into the reserve. 552 uint absolute_max_length = 0; 553 if (_free_regions_at_end_of_collection > _reserve_regions) { 554 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions; 555 } 556 uint desired_max_length = calculate_young_list_desired_max_length(); 557 if (desired_max_length > absolute_max_length) { 558 desired_max_length = absolute_max_length; 559 } 560 561 uint young_list_target_length = 0; 562 if (adaptive_young_list_length()) { 563 if (gcs_are_young()) { 564 young_list_target_length = 565 calculate_young_list_target_length(rs_lengths, 566 base_min_length, 567 desired_min_length, 568 desired_max_length); 569 _rs_lengths_prediction = rs_lengths; 570 } else { 571 // Don't calculate anything and let the code below bound it to 572 // the desired_min_length, i.e., do the next GC as soon as 573 // possible to maximize how many old regions we can add to it. 574 } 575 } else { 576 // The user asked for a fixed young gen so we'll fix the young gen 577 // whether the next GC is young or mixed. 578 young_list_target_length = _young_list_fixed_length; 579 } 580 581 // Make sure we don't go over the desired max length, nor under the 582 // desired min length. In case they clash, desired_min_length wins 583 // which is why that test is second. 584 if (young_list_target_length > desired_max_length) { 585 young_list_target_length = desired_max_length; 586 } 587 if (young_list_target_length < desired_min_length) { 588 young_list_target_length = desired_min_length; 589 } 590 591 assert(young_list_target_length > recorded_survivor_regions(), 592 "we should be able to allocate at least one eden region"); 593 assert(young_list_target_length >= absolute_min_length, "post-condition"); 594 _young_list_target_length = young_list_target_length; 595 596 update_max_gc_locker_expansion(); 597 } 598 599 uint 600 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths, 601 uint base_min_length, 602 uint desired_min_length, 603 uint desired_max_length) { 604 assert(adaptive_young_list_length(), "pre-condition"); 605 assert(gcs_are_young(), "only call this for young GCs"); 606 607 // In case some edge-condition makes the desired max length too small... 608 if (desired_max_length <= desired_min_length) { 609 return desired_min_length; 610 } 611 612 // We'll adjust min_young_length and max_young_length not to include 613 // the already allocated young regions (i.e., so they reflect the 614 // min and max eden regions we'll allocate). The base_min_length 615 // will be reflected in the predictions by the 616 // survivor_regions_evac_time prediction. 617 assert(desired_min_length > base_min_length, "invariant"); 618 uint min_young_length = desired_min_length - base_min_length; 619 assert(desired_max_length > base_min_length, "invariant"); 620 uint max_young_length = desired_max_length - base_min_length; 621 622 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0; 623 double survivor_regions_evac_time = predict_survivor_regions_evac_time(); 624 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq); 625 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff(); 626 size_t scanned_cards = predict_young_card_num(adj_rs_lengths); 627 double base_time_ms = 628 predict_base_elapsed_time_ms(pending_cards, scanned_cards) + 629 survivor_regions_evac_time; 630 uint available_free_regions = _free_regions_at_end_of_collection; 631 uint base_free_regions = 0; 632 if (available_free_regions > _reserve_regions) { 633 base_free_regions = available_free_regions - _reserve_regions; 634 } 635 636 // Here, we will make sure that the shortest young length that 637 // makes sense fits within the target pause time. 638 639 if (predict_will_fit(min_young_length, base_time_ms, 640 base_free_regions, target_pause_time_ms)) { 641 // The shortest young length will fit into the target pause time; 642 // we'll now check whether the absolute maximum number of young 643 // regions will fit in the target pause time. If not, we'll do 644 // a binary search between min_young_length and max_young_length. 645 if (predict_will_fit(max_young_length, base_time_ms, 646 base_free_regions, target_pause_time_ms)) { 647 // The maximum young length will fit into the target pause time. 648 // We are done so set min young length to the maximum length (as 649 // the result is assumed to be returned in min_young_length). 650 min_young_length = max_young_length; 651 } else { 652 // The maximum possible number of young regions will not fit within 653 // the target pause time so we'll search for the optimal 654 // length. The loop invariants are: 655 // 656 // min_young_length < max_young_length 657 // min_young_length is known to fit into the target pause time 658 // max_young_length is known not to fit into the target pause time 659 // 660 // Going into the loop we know the above hold as we've just 661 // checked them. Every time around the loop we check whether 662 // the middle value between min_young_length and 663 // max_young_length fits into the target pause time. If it 664 // does, it becomes the new min. If it doesn't, it becomes 665 // the new max. This way we maintain the loop invariants. 666 667 assert(min_young_length < max_young_length, "invariant"); 668 uint diff = (max_young_length - min_young_length) / 2; 669 while (diff > 0) { 670 uint young_length = min_young_length + diff; 671 if (predict_will_fit(young_length, base_time_ms, 672 base_free_regions, target_pause_time_ms)) { 673 min_young_length = young_length; 674 } else { 675 max_young_length = young_length; 676 } 677 assert(min_young_length < max_young_length, "invariant"); 678 diff = (max_young_length - min_young_length) / 2; 679 } 680 // The results is min_young_length which, according to the 681 // loop invariants, should fit within the target pause time. 682 683 // These are the post-conditions of the binary search above: 684 assert(min_young_length < max_young_length, 685 "otherwise we should have discovered that max_young_length " 686 "fits into the pause target and not done the binary search"); 687 assert(predict_will_fit(min_young_length, base_time_ms, 688 base_free_regions, target_pause_time_ms), 689 "min_young_length, the result of the binary search, should " 690 "fit into the pause target"); 691 assert(!predict_will_fit(min_young_length + 1, base_time_ms, 692 base_free_regions, target_pause_time_ms), 693 "min_young_length, the result of the binary search, should be " 694 "optimal, so no larger length should fit into the pause target"); 695 } 696 } else { 697 // Even the minimum length doesn't fit into the pause time 698 // target, return it as the result nevertheless. 699 } 700 return base_min_length + min_young_length; 701 } 702 703 double G1CollectorPolicy::predict_survivor_regions_evac_time() { 704 double survivor_regions_evac_time = 0.0; 705 for (HeapRegion * r = _recorded_survivor_head; 706 r != NULL && r != _recorded_survivor_tail->get_next_young_region(); 707 r = r->get_next_young_region()) { 708 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young()); 709 } 710 return survivor_regions_evac_time; 711 } 712 713 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() { 714 guarantee( adaptive_young_list_length(), "should not call this otherwise" ); 715 716 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths(); 717 if (rs_lengths > _rs_lengths_prediction) { 718 // add 10% to avoid having to recalculate often 719 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000; 720 update_young_list_target_length(rs_lengths_prediction); 721 } 722 } 723 724 725 726 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size, 727 bool is_tlab, 728 bool* gc_overhead_limit_was_exceeded) { 729 guarantee(false, "Not using this policy feature yet."); 730 return NULL; 731 } 732 733 // This method controls how a collector handles one or more 734 // of its generations being fully allocated. 735 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size, 736 bool is_tlab) { 737 guarantee(false, "Not using this policy feature yet."); 738 return NULL; 739 } 740 741 742 #ifndef PRODUCT 743 bool G1CollectorPolicy::verify_young_ages() { 744 HeapRegion* head = _g1->young_list()->first_region(); 745 return 746 verify_young_ages(head, _short_lived_surv_rate_group); 747 // also call verify_young_ages on any additional surv rate groups 748 } 749 750 bool 751 G1CollectorPolicy::verify_young_ages(HeapRegion* head, 752 SurvRateGroup *surv_rate_group) { 753 guarantee( surv_rate_group != NULL, "pre-condition" ); 754 755 const char* name = surv_rate_group->name(); 756 bool ret = true; 757 int prev_age = -1; 758 759 for (HeapRegion* curr = head; 760 curr != NULL; 761 curr = curr->get_next_young_region()) { 762 SurvRateGroup* group = curr->surv_rate_group(); 763 if (group == NULL && !curr->is_survivor()) { 764 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name); 765 ret = false; 766 } 767 768 if (surv_rate_group == group) { 769 int age = curr->age_in_surv_rate_group(); 770 771 if (age < 0) { 772 gclog_or_tty->print_cr("## %s: encountered negative age", name); 773 ret = false; 774 } 775 776 if (age <= prev_age) { 777 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing " 778 "(%d, %d)", name, age, prev_age); 779 ret = false; 780 } 781 prev_age = age; 782 } 783 } 784 785 return ret; 786 } 787 #endif // PRODUCT 788 789 void G1CollectorPolicy::record_full_collection_start() { 790 _full_collection_start_sec = os::elapsedTime(); 791 record_heap_size_info_at_start(true /* full */); 792 // Release the future to-space so that it is available for compaction into. 793 _g1->set_full_collection(); 794 } 795 796 void G1CollectorPolicy::record_full_collection_end() { 797 // Consider this like a collection pause for the purposes of allocation 798 // since last pause. 799 double end_sec = os::elapsedTime(); 800 double full_gc_time_sec = end_sec - _full_collection_start_sec; 801 double full_gc_time_ms = full_gc_time_sec * 1000.0; 802 803 _trace_old_gen_time_data.record_full_collection(full_gc_time_ms); 804 805 update_recent_gc_times(end_sec, full_gc_time_ms); 806 807 _g1->clear_full_collection(); 808 809 // "Nuke" the heuristics that control the young/mixed GC 810 // transitions and make sure we start with young GCs after the Full GC. 811 set_gcs_are_young(true); 812 _last_young_gc = false; 813 clear_initiate_conc_mark_if_possible(); 814 clear_during_initial_mark_pause(); 815 _in_marking_window = false; 816 _in_marking_window_im = false; 817 818 _short_lived_surv_rate_group->start_adding_regions(); 819 // also call this on any additional surv rate groups 820 821 record_survivor_regions(0, NULL, NULL); 822 823 _free_regions_at_end_of_collection = _g1->num_free_regions(); 824 // Reset survivors SurvRateGroup. 825 _survivor_surv_rate_group->reset(); 826 update_young_list_target_length(); 827 _collectionSetChooser->clear(); 828 } 829 830 void G1CollectorPolicy::record_stop_world_start() { 831 _stop_world_start = os::elapsedTime(); 832 } 833 834 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) { 835 // We only need to do this here as the policy will only be applied 836 // to the GC we're about to start. so, no point is calculating this 837 // every time we calculate / recalculate the target young length. 838 update_survivors_policy(); 839 840 assert(_g1->used() == _g1->recalculate_used(), 841 err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT, 842 _g1->used(), _g1->recalculate_used())); 843 844 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0; 845 _trace_young_gen_time_data.record_start_collection(s_w_t_ms); 846 _stop_world_start = 0.0; 847 848 record_heap_size_info_at_start(false /* full */); 849 850 phase_times()->record_cur_collection_start_sec(start_time_sec); 851 _pending_cards = _g1->pending_card_num(); 852 853 _collection_set_bytes_used_before = 0; 854 _bytes_copied_during_gc = 0; 855 856 _last_gc_was_young = false; 857 858 // do that for any other surv rate groups 859 _short_lived_surv_rate_group->stop_adding_regions(); 860 _survivors_age_table.clear(); 861 862 assert( verify_young_ages(), "region age verification" ); 863 } 864 865 void G1CollectorPolicy::record_concurrent_mark_init_end(double 866 mark_init_elapsed_time_ms) { 867 _during_marking = true; 868 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now"); 869 clear_during_initial_mark_pause(); 870 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms; 871 } 872 873 void G1CollectorPolicy::record_concurrent_mark_remark_start() { 874 _mark_remark_start_sec = os::elapsedTime(); 875 _during_marking = false; 876 } 877 878 void G1CollectorPolicy::record_concurrent_mark_remark_end() { 879 double end_time_sec = os::elapsedTime(); 880 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0; 881 _concurrent_mark_remark_times_ms->add(elapsed_time_ms); 882 _cur_mark_stop_world_time_ms += elapsed_time_ms; 883 _prev_collection_pause_end_ms += elapsed_time_ms; 884 885 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true); 886 } 887 888 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() { 889 _mark_cleanup_start_sec = os::elapsedTime(); 890 } 891 892 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() { 893 _last_young_gc = true; 894 _in_marking_window = false; 895 } 896 897 void G1CollectorPolicy::record_concurrent_pause() { 898 if (_stop_world_start > 0.0) { 899 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0; 900 _trace_young_gen_time_data.record_yield_time(yield_ms); 901 } 902 } 903 904 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) { 905 if (_g1->concurrent_mark()->cmThread()->during_cycle()) { 906 return false; 907 } 908 909 size_t marking_initiating_used_threshold = 910 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent; 911 size_t cur_used_bytes = _g1->non_young_capacity_bytes(); 912 size_t alloc_byte_size = alloc_word_size * HeapWordSize; 913 914 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) { 915 if (gcs_are_young() && !_last_young_gc) { 916 ergo_verbose5(ErgoConcCycles, 917 "request concurrent cycle initiation", 918 ergo_format_reason("occupancy higher than threshold") 919 ergo_format_byte("occupancy") 920 ergo_format_byte("allocation request") 921 ergo_format_byte_perc("threshold") 922 ergo_format_str("source"), 923 cur_used_bytes, 924 alloc_byte_size, 925 marking_initiating_used_threshold, 926 (double) InitiatingHeapOccupancyPercent, 927 source); 928 return true; 929 } else { 930 ergo_verbose5(ErgoConcCycles, 931 "do not request concurrent cycle initiation", 932 ergo_format_reason("still doing mixed collections") 933 ergo_format_byte("occupancy") 934 ergo_format_byte("allocation request") 935 ergo_format_byte_perc("threshold") 936 ergo_format_str("source"), 937 cur_used_bytes, 938 alloc_byte_size, 939 marking_initiating_used_threshold, 940 (double) InitiatingHeapOccupancyPercent, 941 source); 942 } 943 } 944 945 return false; 946 } 947 948 // Anything below that is considered to be zero 949 #define MIN_TIMER_GRANULARITY 0.0000001 950 951 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info) { 952 double end_time_sec = os::elapsedTime(); 953 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(), 954 "otherwise, the subtraction below does not make sense"); 955 size_t rs_size = 956 _cur_collection_pause_used_regions_at_start - cset_region_length(); 957 size_t cur_used_bytes = _g1->used(); 958 assert(cur_used_bytes == _g1->recalculate_used(), "It should!"); 959 bool last_pause_included_initial_mark = false; 960 bool update_stats = !_g1->evacuation_failed(); 961 962 #ifndef PRODUCT 963 if (G1YoungSurvRateVerbose) { 964 gclog_or_tty->cr(); 965 _short_lived_surv_rate_group->print(); 966 // do that for any other surv rate groups too 967 } 968 #endif // PRODUCT 969 970 last_pause_included_initial_mark = during_initial_mark_pause(); 971 if (last_pause_included_initial_mark) { 972 record_concurrent_mark_init_end(0.0); 973 } else if (need_to_start_conc_mark("end of GC")) { 974 // Note: this might have already been set, if during the last 975 // pause we decided to start a cycle but at the beginning of 976 // this pause we decided to postpone it. That's OK. 977 set_initiate_conc_mark_if_possible(); 978 } 979 980 _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0, 981 end_time_sec, false); 982 983 evacuation_info.set_collectionset_used_before(_collection_set_bytes_used_before); 984 evacuation_info.set_bytes_copied(_bytes_copied_during_gc); 985 986 if (update_stats) { 987 _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times()); 988 // this is where we update the allocation rate of the application 989 double app_time_ms = 990 (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms); 991 if (app_time_ms < MIN_TIMER_GRANULARITY) { 992 // This usually happens due to the timer not having the required 993 // granularity. Some Linuxes are the usual culprits. 994 // We'll just set it to something (arbitrarily) small. 995 app_time_ms = 1.0; 996 } 997 // We maintain the invariant that all objects allocated by mutator 998 // threads will be allocated out of eden regions. So, we can use 999 // the eden region number allocated since the previous GC to 1000 // calculate the application's allocate rate. The only exception 1001 // to that is humongous objects that are allocated separately. But 1002 // given that humongous object allocations do not really affect 1003 // either the pause's duration nor when the next pause will take 1004 // place we can safely ignore them here. 1005 uint regions_allocated = eden_cset_region_length(); 1006 double alloc_rate_ms = (double) regions_allocated / app_time_ms; 1007 _alloc_rate_ms_seq->add(alloc_rate_ms); 1008 1009 double interval_ms = 1010 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0; 1011 update_recent_gc_times(end_time_sec, pause_time_ms); 1012 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms; 1013 if (recent_avg_pause_time_ratio() < 0.0 || 1014 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) { 1015 #ifndef PRODUCT 1016 // Dump info to allow post-facto debugging 1017 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds"); 1018 gclog_or_tty->print_cr("-------------------------------------------"); 1019 gclog_or_tty->print_cr("Recent GC Times (ms):"); 1020 _recent_gc_times_ms->dump(); 1021 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec); 1022 _recent_prev_end_times_for_all_gcs_sec->dump(); 1023 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f", 1024 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio()); 1025 // In debug mode, terminate the JVM if the user wants to debug at this point. 1026 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above"); 1027 #endif // !PRODUCT 1028 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in 1029 // CR 6902692 by redoing the manner in which the ratio is incrementally computed. 1030 if (_recent_avg_pause_time_ratio < 0.0) { 1031 _recent_avg_pause_time_ratio = 0.0; 1032 } else { 1033 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant"); 1034 _recent_avg_pause_time_ratio = 1.0; 1035 } 1036 } 1037 } 1038 1039 bool new_in_marking_window = _in_marking_window; 1040 bool new_in_marking_window_im = false; 1041 if (last_pause_included_initial_mark) { 1042 new_in_marking_window = true; 1043 new_in_marking_window_im = true; 1044 } 1045 1046 if (_last_young_gc) { 1047 // This is supposed to to be the "last young GC" before we start 1048 // doing mixed GCs. Here we decide whether to start mixed GCs or not. 1049 1050 if (!last_pause_included_initial_mark) { 1051 if (next_gc_should_be_mixed("start mixed GCs", 1052 "do not start mixed GCs")) { 1053 set_gcs_are_young(false); 1054 } 1055 } else { 1056 ergo_verbose0(ErgoMixedGCs, 1057 "do not start mixed GCs", 1058 ergo_format_reason("concurrent cycle is about to start")); 1059 } 1060 _last_young_gc = false; 1061 } 1062 1063 if (!_last_gc_was_young) { 1064 // This is a mixed GC. Here we decide whether to continue doing 1065 // mixed GCs or not. 1066 1067 if (!next_gc_should_be_mixed("continue mixed GCs", 1068 "do not continue mixed GCs")) { 1069 set_gcs_are_young(true); 1070 } 1071 } 1072 1073 _short_lived_surv_rate_group->start_adding_regions(); 1074 // Do that for any other surv rate groups 1075 1076 if (update_stats) { 1077 double cost_per_card_ms = 0.0; 1078 if (_pending_cards > 0) { 1079 cost_per_card_ms = phase_times()->average_time(G1GCPhaseTimes::UpdateRS) / (double) _pending_cards; 1080 _cost_per_card_ms_seq->add(cost_per_card_ms); 1081 } 1082 1083 size_t cards_scanned = _g1->cards_scanned(); 1084 1085 double cost_per_entry_ms = 0.0; 1086 if (cards_scanned > 10) { 1087 cost_per_entry_ms = phase_times()->average_time(G1GCPhaseTimes::ScanRS) / (double) cards_scanned; 1088 if (_last_gc_was_young) { 1089 _cost_per_entry_ms_seq->add(cost_per_entry_ms); 1090 } else { 1091 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms); 1092 } 1093 } 1094 1095 if (_max_rs_lengths > 0) { 1096 double cards_per_entry_ratio = 1097 (double) cards_scanned / (double) _max_rs_lengths; 1098 if (_last_gc_was_young) { 1099 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio); 1100 } else { 1101 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio); 1102 } 1103 } 1104 1105 // This is defensive. For a while _max_rs_lengths could get 1106 // smaller than _recorded_rs_lengths which was causing 1107 // rs_length_diff to get very large and mess up the RSet length 1108 // predictions. The reason was unsafe concurrent updates to the 1109 // _inc_cset_recorded_rs_lengths field which the code below guards 1110 // against (see CR 7118202). This bug has now been fixed (see CR 1111 // 7119027). However, I'm still worried that 1112 // _inc_cset_recorded_rs_lengths might still end up somewhat 1113 // inaccurate. The concurrent refinement thread calculates an 1114 // RSet's length concurrently with other CR threads updating it 1115 // which might cause it to calculate the length incorrectly (if, 1116 // say, it's in mid-coarsening). So I'll leave in the defensive 1117 // conditional below just in case. 1118 size_t rs_length_diff = 0; 1119 if (_max_rs_lengths > _recorded_rs_lengths) { 1120 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths; 1121 } 1122 _rs_length_diff_seq->add((double) rs_length_diff); 1123 1124 size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes; 1125 size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes; 1126 double cost_per_byte_ms = 0.0; 1127 1128 if (copied_bytes > 0) { 1129 cost_per_byte_ms = phase_times()->average_time(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes; 1130 if (_in_marking_window) { 1131 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms); 1132 } else { 1133 _cost_per_byte_ms_seq->add(cost_per_byte_ms); 1134 } 1135 } 1136 1137 double all_other_time_ms = pause_time_ms - 1138 (phase_times()->average_time(G1GCPhaseTimes::UpdateRS) + phase_times()->average_time(G1GCPhaseTimes::ScanRS) 1139 + phase_times()->average_time(G1GCPhaseTimes::ObjCopy) + phase_times()->average_time(G1GCPhaseTimes::Termination)); 1140 1141 double young_other_time_ms = 0.0; 1142 if (young_cset_region_length() > 0) { 1143 young_other_time_ms = 1144 phase_times()->young_cset_choice_time_ms() + 1145 phase_times()->young_free_cset_time_ms(); 1146 _young_other_cost_per_region_ms_seq->add(young_other_time_ms / 1147 (double) young_cset_region_length()); 1148 } 1149 double non_young_other_time_ms = 0.0; 1150 if (old_cset_region_length() > 0) { 1151 non_young_other_time_ms = 1152 phase_times()->non_young_cset_choice_time_ms() + 1153 phase_times()->non_young_free_cset_time_ms(); 1154 1155 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms / 1156 (double) old_cset_region_length()); 1157 } 1158 1159 double constant_other_time_ms = all_other_time_ms - 1160 (young_other_time_ms + non_young_other_time_ms); 1161 _constant_other_time_ms_seq->add(constant_other_time_ms); 1162 1163 double survival_ratio = 0.0; 1164 if (_collection_set_bytes_used_before > 0) { 1165 survival_ratio = (double) _bytes_copied_during_gc / 1166 (double) _collection_set_bytes_used_before; 1167 } 1168 1169 _pending_cards_seq->add((double) _pending_cards); 1170 _rs_lengths_seq->add((double) _max_rs_lengths); 1171 } 1172 1173 _in_marking_window = new_in_marking_window; 1174 _in_marking_window_im = new_in_marking_window_im; 1175 _free_regions_at_end_of_collection = _g1->num_free_regions(); 1176 update_young_list_target_length(); 1177 1178 // Note that _mmu_tracker->max_gc_time() returns the time in seconds. 1179 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0; 1180 adjust_concurrent_refinement(phase_times()->average_time(G1GCPhaseTimes::UpdateRS), 1181 phase_times()->sub_count_sum(G1GCPhaseTimes::UpdateRS), update_rs_time_goal_ms); 1182 1183 _collectionSetChooser->verify(); 1184 } 1185 1186 #define EXT_SIZE_FORMAT "%.1f%s" 1187 #define EXT_SIZE_PARAMS(bytes) \ 1188 byte_size_in_proper_unit((double)(bytes)), \ 1189 proper_unit_for_byte_size((bytes)) 1190 1191 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) { 1192 YoungList* young_list = _g1->young_list(); 1193 _eden_used_bytes_before_gc = young_list->eden_used_bytes(); 1194 _survivor_used_bytes_before_gc = young_list->survivor_used_bytes(); 1195 _heap_capacity_bytes_before_gc = _g1->capacity(); 1196 _heap_used_bytes_before_gc = _g1->used(); 1197 _cur_collection_pause_used_regions_at_start = _g1->num_used_regions(); 1198 1199 _eden_capacity_bytes_before_gc = 1200 (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc; 1201 1202 if (full) { 1203 _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes(); 1204 } 1205 } 1206 1207 void G1CollectorPolicy::print_heap_transition() { 1208 _g1->print_size_transition(gclog_or_tty, 1209 _heap_used_bytes_before_gc, 1210 _g1->used(), 1211 _g1->capacity()); 1212 } 1213 1214 void G1CollectorPolicy::print_detailed_heap_transition(bool full) { 1215 YoungList* young_list = _g1->young_list(); 1216 1217 size_t eden_used_bytes_after_gc = young_list->eden_used_bytes(); 1218 size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes(); 1219 size_t heap_used_bytes_after_gc = _g1->used(); 1220 1221 size_t heap_capacity_bytes_after_gc = _g1->capacity(); 1222 size_t eden_capacity_bytes_after_gc = 1223 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc; 1224 1225 gclog_or_tty->print( 1226 " [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") " 1227 "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" " 1228 "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->" 1229 EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]", 1230 EXT_SIZE_PARAMS(_eden_used_bytes_before_gc), 1231 EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc), 1232 EXT_SIZE_PARAMS(eden_used_bytes_after_gc), 1233 EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc), 1234 EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc), 1235 EXT_SIZE_PARAMS(survivor_used_bytes_after_gc), 1236 EXT_SIZE_PARAMS(_heap_used_bytes_before_gc), 1237 EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc), 1238 EXT_SIZE_PARAMS(heap_used_bytes_after_gc), 1239 EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc)); 1240 1241 if (full) { 1242 MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc); 1243 } 1244 1245 gclog_or_tty->cr(); 1246 } 1247 1248 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time, 1249 double update_rs_processed_buffers, 1250 double goal_ms) { 1251 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 1252 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine(); 1253 1254 if (G1UseAdaptiveConcRefinement) { 1255 const int k_gy = 3, k_gr = 6; 1256 const double inc_k = 1.1, dec_k = 0.9; 1257 1258 int g = cg1r->green_zone(); 1259 if (update_rs_time > goal_ms) { 1260 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing. 1261 } else { 1262 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) { 1263 g = (int)MAX2(g * inc_k, g + 1.0); 1264 } 1265 } 1266 // Change the refinement threads params 1267 cg1r->set_green_zone(g); 1268 cg1r->set_yellow_zone(g * k_gy); 1269 cg1r->set_red_zone(g * k_gr); 1270 cg1r->reinitialize_threads(); 1271 1272 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1); 1273 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta, 1274 cg1r->yellow_zone()); 1275 // Change the barrier params 1276 dcqs.set_process_completed_threshold(processing_threshold); 1277 dcqs.set_max_completed_queue(cg1r->red_zone()); 1278 } 1279 1280 int curr_queue_size = dcqs.completed_buffers_num(); 1281 if (curr_queue_size >= cg1r->yellow_zone()) { 1282 dcqs.set_completed_queue_padding(curr_queue_size); 1283 } else { 1284 dcqs.set_completed_queue_padding(0); 1285 } 1286 dcqs.notify_if_necessary(); 1287 } 1288 1289 double 1290 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards, 1291 size_t scanned_cards) { 1292 return 1293 predict_rs_update_time_ms(pending_cards) + 1294 predict_rs_scan_time_ms(scanned_cards) + 1295 predict_constant_other_time_ms(); 1296 } 1297 1298 double 1299 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) { 1300 size_t rs_length = predict_rs_length_diff(); 1301 size_t card_num; 1302 if (gcs_are_young()) { 1303 card_num = predict_young_card_num(rs_length); 1304 } else { 1305 card_num = predict_non_young_card_num(rs_length); 1306 } 1307 return predict_base_elapsed_time_ms(pending_cards, card_num); 1308 } 1309 1310 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) { 1311 size_t bytes_to_copy; 1312 if (hr->is_marked()) 1313 bytes_to_copy = hr->max_live_bytes(); 1314 else { 1315 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant"); 1316 int age = hr->age_in_surv_rate_group(); 1317 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group()); 1318 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate); 1319 } 1320 return bytes_to_copy; 1321 } 1322 1323 double 1324 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr, 1325 bool for_young_gc) { 1326 size_t rs_length = hr->rem_set()->occupied(); 1327 size_t card_num; 1328 1329 // Predicting the number of cards is based on which type of GC 1330 // we're predicting for. 1331 if (for_young_gc) { 1332 card_num = predict_young_card_num(rs_length); 1333 } else { 1334 card_num = predict_non_young_card_num(rs_length); 1335 } 1336 size_t bytes_to_copy = predict_bytes_to_copy(hr); 1337 1338 double region_elapsed_time_ms = 1339 predict_rs_scan_time_ms(card_num) + 1340 predict_object_copy_time_ms(bytes_to_copy); 1341 1342 // The prediction of the "other" time for this region is based 1343 // upon the region type and NOT the GC type. 1344 if (hr->is_young()) { 1345 region_elapsed_time_ms += predict_young_other_time_ms(1); 1346 } else { 1347 region_elapsed_time_ms += predict_non_young_other_time_ms(1); 1348 } 1349 return region_elapsed_time_ms; 1350 } 1351 1352 void 1353 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length, 1354 uint survivor_cset_region_length) { 1355 _eden_cset_region_length = eden_cset_region_length; 1356 _survivor_cset_region_length = survivor_cset_region_length; 1357 _old_cset_region_length = 0; 1358 } 1359 1360 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) { 1361 _recorded_rs_lengths = rs_lengths; 1362 } 1363 1364 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec, 1365 double elapsed_ms) { 1366 _recent_gc_times_ms->add(elapsed_ms); 1367 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec); 1368 _prev_collection_pause_end_ms = end_time_sec * 1000.0; 1369 } 1370 1371 size_t G1CollectorPolicy::expansion_amount() { 1372 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0; 1373 double threshold = _gc_overhead_perc; 1374 if (recent_gc_overhead > threshold) { 1375 // We will double the existing space, or take 1376 // G1ExpandByPercentOfAvailable % of the available expansion 1377 // space, whichever is smaller, bounded below by a minimum 1378 // expansion (unless that's all that's left.) 1379 const size_t min_expand_bytes = 1*M; 1380 size_t reserved_bytes = _g1->max_capacity(); 1381 size_t committed_bytes = _g1->capacity(); 1382 size_t uncommitted_bytes = reserved_bytes - committed_bytes; 1383 size_t expand_bytes; 1384 size_t expand_bytes_via_pct = 1385 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100; 1386 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes); 1387 expand_bytes = MAX2(expand_bytes, min_expand_bytes); 1388 expand_bytes = MIN2(expand_bytes, uncommitted_bytes); 1389 1390 ergo_verbose5(ErgoHeapSizing, 1391 "attempt heap expansion", 1392 ergo_format_reason("recent GC overhead higher than " 1393 "threshold after GC") 1394 ergo_format_perc("recent GC overhead") 1395 ergo_format_perc("threshold") 1396 ergo_format_byte("uncommitted") 1397 ergo_format_byte_perc("calculated expansion amount"), 1398 recent_gc_overhead, threshold, 1399 uncommitted_bytes, 1400 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable); 1401 1402 return expand_bytes; 1403 } else { 1404 return 0; 1405 } 1406 } 1407 1408 void G1CollectorPolicy::print_tracing_info() const { 1409 _trace_young_gen_time_data.print(); 1410 _trace_old_gen_time_data.print(); 1411 } 1412 1413 void G1CollectorPolicy::print_yg_surv_rate_info() const { 1414 #ifndef PRODUCT 1415 _short_lived_surv_rate_group->print_surv_rate_summary(); 1416 // add this call for any other surv rate groups 1417 #endif // PRODUCT 1418 } 1419 1420 bool G1CollectorPolicy::is_young_list_full() { 1421 uint young_list_length = _g1->young_list()->length(); 1422 uint young_list_target_length = _young_list_target_length; 1423 return young_list_length >= young_list_target_length; 1424 } 1425 1426 bool G1CollectorPolicy::can_expand_young_list() { 1427 uint young_list_length = _g1->young_list()->length(); 1428 uint young_list_max_length = _young_list_max_length; 1429 return young_list_length < young_list_max_length; 1430 } 1431 1432 void G1CollectorPolicy::update_max_gc_locker_expansion() { 1433 uint expansion_region_num = 0; 1434 if (GCLockerEdenExpansionPercent > 0) { 1435 double perc = (double) GCLockerEdenExpansionPercent / 100.0; 1436 double expansion_region_num_d = perc * (double) _young_list_target_length; 1437 // We use ceiling so that if expansion_region_num_d is > 0.0 (but 1438 // less than 1.0) we'll get 1. 1439 expansion_region_num = (uint) ceil(expansion_region_num_d); 1440 } else { 1441 assert(expansion_region_num == 0, "sanity"); 1442 } 1443 _young_list_max_length = _young_list_target_length + expansion_region_num; 1444 assert(_young_list_target_length <= _young_list_max_length, "post-condition"); 1445 } 1446 1447 // Calculates survivor space parameters. 1448 void G1CollectorPolicy::update_survivors_policy() { 1449 double max_survivor_regions_d = 1450 (double) _young_list_target_length / (double) SurvivorRatio; 1451 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but 1452 // smaller than 1.0) we'll get 1. 1453 _max_survivor_regions = (uint) ceil(max_survivor_regions_d); 1454 1455 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold( 1456 HeapRegion::GrainWords * _max_survivor_regions); 1457 } 1458 1459 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle( 1460 GCCause::Cause gc_cause) { 1461 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle(); 1462 if (!during_cycle) { 1463 ergo_verbose1(ErgoConcCycles, 1464 "request concurrent cycle initiation", 1465 ergo_format_reason("requested by GC cause") 1466 ergo_format_str("GC cause"), 1467 GCCause::to_string(gc_cause)); 1468 set_initiate_conc_mark_if_possible(); 1469 return true; 1470 } else { 1471 ergo_verbose1(ErgoConcCycles, 1472 "do not request concurrent cycle initiation", 1473 ergo_format_reason("concurrent cycle already in progress") 1474 ergo_format_str("GC cause"), 1475 GCCause::to_string(gc_cause)); 1476 return false; 1477 } 1478 } 1479 1480 void 1481 G1CollectorPolicy::decide_on_conc_mark_initiation() { 1482 // We are about to decide on whether this pause will be an 1483 // initial-mark pause. 1484 1485 // First, during_initial_mark_pause() should not be already set. We 1486 // will set it here if we have to. However, it should be cleared by 1487 // the end of the pause (it's only set for the duration of an 1488 // initial-mark pause). 1489 assert(!during_initial_mark_pause(), "pre-condition"); 1490 1491 if (initiate_conc_mark_if_possible()) { 1492 // We had noticed on a previous pause that the heap occupancy has 1493 // gone over the initiating threshold and we should start a 1494 // concurrent marking cycle. So we might initiate one. 1495 1496 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle(); 1497 if (!during_cycle) { 1498 // The concurrent marking thread is not "during a cycle", i.e., 1499 // it has completed the last one. So we can go ahead and 1500 // initiate a new cycle. 1501 1502 set_during_initial_mark_pause(); 1503 // We do not allow mixed GCs during marking. 1504 if (!gcs_are_young()) { 1505 set_gcs_are_young(true); 1506 ergo_verbose0(ErgoMixedGCs, 1507 "end mixed GCs", 1508 ergo_format_reason("concurrent cycle is about to start")); 1509 } 1510 1511 // And we can now clear initiate_conc_mark_if_possible() as 1512 // we've already acted on it. 1513 clear_initiate_conc_mark_if_possible(); 1514 1515 ergo_verbose0(ErgoConcCycles, 1516 "initiate concurrent cycle", 1517 ergo_format_reason("concurrent cycle initiation requested")); 1518 } else { 1519 // The concurrent marking thread is still finishing up the 1520 // previous cycle. If we start one right now the two cycles 1521 // overlap. In particular, the concurrent marking thread might 1522 // be in the process of clearing the next marking bitmap (which 1523 // we will use for the next cycle if we start one). Starting a 1524 // cycle now will be bad given that parts of the marking 1525 // information might get cleared by the marking thread. And we 1526 // cannot wait for the marking thread to finish the cycle as it 1527 // periodically yields while clearing the next marking bitmap 1528 // and, if it's in a yield point, it's waiting for us to 1529 // finish. So, at this point we will not start a cycle and we'll 1530 // let the concurrent marking thread complete the last one. 1531 ergo_verbose0(ErgoConcCycles, 1532 "do not initiate concurrent cycle", 1533 ergo_format_reason("concurrent cycle already in progress")); 1534 } 1535 } 1536 } 1537 1538 class ParKnownGarbageHRClosure: public HeapRegionClosure { 1539 G1CollectedHeap* _g1h; 1540 CSetChooserParUpdater _cset_updater; 1541 1542 public: 1543 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted, 1544 uint chunk_size) : 1545 _g1h(G1CollectedHeap::heap()), 1546 _cset_updater(hrSorted, true /* parallel */, chunk_size) { } 1547 1548 bool doHeapRegion(HeapRegion* r) { 1549 // Do we have any marking information for this region? 1550 if (r->is_marked()) { 1551 // We will skip any region that's currently used as an old GC 1552 // alloc region (we should not consider those for collection 1553 // before we fill them up). 1554 if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) { 1555 _cset_updater.add_region(r); 1556 } 1557 } 1558 return false; 1559 } 1560 }; 1561 1562 class ParKnownGarbageTask: public AbstractGangTask { 1563 CollectionSetChooser* _hrSorted; 1564 uint _chunk_size; 1565 G1CollectedHeap* _g1; 1566 HeapRegionClaimer _hrclaimer; 1567 1568 public: 1569 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) : 1570 AbstractGangTask("ParKnownGarbageTask"), 1571 _hrSorted(hrSorted), _chunk_size(chunk_size), 1572 _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {} 1573 1574 void work(uint worker_id) { 1575 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size); 1576 _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer); 1577 } 1578 }; 1579 1580 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) { 1581 assert(n_workers > 0, "Active gc workers should be greater than 0"); 1582 const uint overpartition_factor = 4; 1583 const uint min_chunk_size = MAX2(n_regions / n_workers, 1U); 1584 return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size); 1585 } 1586 1587 void 1588 G1CollectorPolicy::record_concurrent_mark_cleanup_end(uint n_workers) { 1589 _collectionSetChooser->clear(); 1590 1591 uint n_regions = _g1->num_regions(); 1592 uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions); 1593 _collectionSetChooser->prepare_for_par_region_addition(n_regions, chunk_size); 1594 ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers); 1595 _g1->workers()->run_task(&par_known_garbage_task); 1596 1597 _collectionSetChooser->sort_regions(); 1598 1599 double end_sec = os::elapsedTime(); 1600 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0; 1601 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms); 1602 _cur_mark_stop_world_time_ms += elapsed_time_ms; 1603 _prev_collection_pause_end_ms += elapsed_time_ms; 1604 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true); 1605 } 1606 1607 // Add the heap region at the head of the non-incremental collection set 1608 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) { 1609 assert(_inc_cset_build_state == Active, "Precondition"); 1610 assert(hr->is_old(), "the region should be old"); 1611 1612 assert(!hr->in_collection_set(), "should not already be in the CSet"); 1613 hr->set_in_collection_set(true); 1614 hr->set_next_in_collection_set(_collection_set); 1615 _collection_set = hr; 1616 _collection_set_bytes_used_before += hr->used(); 1617 _g1->register_old_region_with_in_cset_fast_test(hr); 1618 size_t rs_length = hr->rem_set()->occupied(); 1619 _recorded_rs_lengths += rs_length; 1620 _old_cset_region_length += 1; 1621 } 1622 1623 // Initialize the per-collection-set information 1624 void G1CollectorPolicy::start_incremental_cset_building() { 1625 assert(_inc_cset_build_state == Inactive, "Precondition"); 1626 1627 _inc_cset_head = NULL; 1628 _inc_cset_tail = NULL; 1629 _inc_cset_bytes_used_before = 0; 1630 1631 _inc_cset_max_finger = 0; 1632 _inc_cset_recorded_rs_lengths = 0; 1633 _inc_cset_recorded_rs_lengths_diffs = 0; 1634 _inc_cset_predicted_elapsed_time_ms = 0.0; 1635 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0; 1636 _inc_cset_build_state = Active; 1637 } 1638 1639 void G1CollectorPolicy::finalize_incremental_cset_building() { 1640 assert(_inc_cset_build_state == Active, "Precondition"); 1641 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint"); 1642 1643 // The two "main" fields, _inc_cset_recorded_rs_lengths and 1644 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread 1645 // that adds a new region to the CSet. Further updates by the 1646 // concurrent refinement thread that samples the young RSet lengths 1647 // are accumulated in the *_diffs fields. Here we add the diffs to 1648 // the "main" fields. 1649 1650 if (_inc_cset_recorded_rs_lengths_diffs >= 0) { 1651 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs; 1652 } else { 1653 // This is defensive. The diff should in theory be always positive 1654 // as RSets can only grow between GCs. However, given that we 1655 // sample their size concurrently with other threads updating them 1656 // it's possible that we might get the wrong size back, which 1657 // could make the calculations somewhat inaccurate. 1658 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs); 1659 if (_inc_cset_recorded_rs_lengths >= diffs) { 1660 _inc_cset_recorded_rs_lengths -= diffs; 1661 } else { 1662 _inc_cset_recorded_rs_lengths = 0; 1663 } 1664 } 1665 _inc_cset_predicted_elapsed_time_ms += 1666 _inc_cset_predicted_elapsed_time_ms_diffs; 1667 1668 _inc_cset_recorded_rs_lengths_diffs = 0; 1669 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0; 1670 } 1671 1672 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) { 1673 // This routine is used when: 1674 // * adding survivor regions to the incremental cset at the end of an 1675 // evacuation pause, 1676 // * adding the current allocation region to the incremental cset 1677 // when it is retired, and 1678 // * updating existing policy information for a region in the 1679 // incremental cset via young list RSet sampling. 1680 // Therefore this routine may be called at a safepoint by the 1681 // VM thread, or in-between safepoints by mutator threads (when 1682 // retiring the current allocation region) or a concurrent 1683 // refine thread (RSet sampling). 1684 1685 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young()); 1686 size_t used_bytes = hr->used(); 1687 _inc_cset_recorded_rs_lengths += rs_length; 1688 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms; 1689 _inc_cset_bytes_used_before += used_bytes; 1690 1691 // Cache the values we have added to the aggregated information 1692 // in the heap region in case we have to remove this region from 1693 // the incremental collection set, or it is updated by the 1694 // rset sampling code 1695 hr->set_recorded_rs_length(rs_length); 1696 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms); 1697 } 1698 1699 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr, 1700 size_t new_rs_length) { 1701 // Update the CSet information that is dependent on the new RS length 1702 assert(hr->is_young(), "Precondition"); 1703 assert(!SafepointSynchronize::is_at_safepoint(), 1704 "should not be at a safepoint"); 1705 1706 // We could have updated _inc_cset_recorded_rs_lengths and 1707 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do 1708 // that atomically, as this code is executed by a concurrent 1709 // refinement thread, potentially concurrently with a mutator thread 1710 // allocating a new region and also updating the same fields. To 1711 // avoid the atomic operations we accumulate these updates on two 1712 // separate fields (*_diffs) and we'll just add them to the "main" 1713 // fields at the start of a GC. 1714 1715 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length(); 1716 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length; 1717 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff; 1718 1719 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms(); 1720 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young()); 1721 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms; 1722 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff; 1723 1724 hr->set_recorded_rs_length(new_rs_length); 1725 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms); 1726 } 1727 1728 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) { 1729 assert(hr->is_young(), "invariant"); 1730 assert(hr->young_index_in_cset() > -1, "should have already been set"); 1731 assert(_inc_cset_build_state == Active, "Precondition"); 1732 1733 // We need to clear and set the cached recorded/cached collection set 1734 // information in the heap region here (before the region gets added 1735 // to the collection set). An individual heap region's cached values 1736 // are calculated, aggregated with the policy collection set info, 1737 // and cached in the heap region here (initially) and (subsequently) 1738 // by the Young List sampling code. 1739 1740 size_t rs_length = hr->rem_set()->occupied(); 1741 add_to_incremental_cset_info(hr, rs_length); 1742 1743 HeapWord* hr_end = hr->end(); 1744 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end); 1745 1746 assert(!hr->in_collection_set(), "invariant"); 1747 hr->set_in_collection_set(true); 1748 assert( hr->next_in_collection_set() == NULL, "invariant"); 1749 1750 _g1->register_young_region_with_in_cset_fast_test(hr); 1751 } 1752 1753 // Add the region at the RHS of the incremental cset 1754 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) { 1755 // We should only ever be appending survivors at the end of a pause 1756 assert(hr->is_survivor(), "Logic"); 1757 1758 // Do the 'common' stuff 1759 add_region_to_incremental_cset_common(hr); 1760 1761 // Now add the region at the right hand side 1762 if (_inc_cset_tail == NULL) { 1763 assert(_inc_cset_head == NULL, "invariant"); 1764 _inc_cset_head = hr; 1765 } else { 1766 _inc_cset_tail->set_next_in_collection_set(hr); 1767 } 1768 _inc_cset_tail = hr; 1769 } 1770 1771 // Add the region to the LHS of the incremental cset 1772 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) { 1773 // Survivors should be added to the RHS at the end of a pause 1774 assert(hr->is_eden(), "Logic"); 1775 1776 // Do the 'common' stuff 1777 add_region_to_incremental_cset_common(hr); 1778 1779 // Add the region at the left hand side 1780 hr->set_next_in_collection_set(_inc_cset_head); 1781 if (_inc_cset_head == NULL) { 1782 assert(_inc_cset_tail == NULL, "Invariant"); 1783 _inc_cset_tail = hr; 1784 } 1785 _inc_cset_head = hr; 1786 } 1787 1788 #ifndef PRODUCT 1789 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) { 1790 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be"); 1791 1792 st->print_cr("\nCollection_set:"); 1793 HeapRegion* csr = list_head; 1794 while (csr != NULL) { 1795 HeapRegion* next = csr->next_in_collection_set(); 1796 assert(csr->in_collection_set(), "bad CS"); 1797 st->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d", 1798 HR_FORMAT_PARAMS(csr), 1799 csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(), 1800 csr->age_in_surv_rate_group_cond()); 1801 csr = next; 1802 } 1803 } 1804 #endif // !PRODUCT 1805 1806 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) { 1807 // Returns the given amount of reclaimable bytes (that represents 1808 // the amount of reclaimable space still to be collected) as a 1809 // percentage of the current heap capacity. 1810 size_t capacity_bytes = _g1->capacity(); 1811 return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes; 1812 } 1813 1814 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str, 1815 const char* false_action_str) { 1816 CollectionSetChooser* cset_chooser = _collectionSetChooser; 1817 if (cset_chooser->is_empty()) { 1818 ergo_verbose0(ErgoMixedGCs, 1819 false_action_str, 1820 ergo_format_reason("candidate old regions not available")); 1821 return false; 1822 } 1823 1824 // Is the amount of uncollected reclaimable space above G1HeapWastePercent? 1825 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes(); 1826 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes); 1827 double threshold = (double) G1HeapWastePercent; 1828 if (reclaimable_perc <= threshold) { 1829 ergo_verbose4(ErgoMixedGCs, 1830 false_action_str, 1831 ergo_format_reason("reclaimable percentage not over threshold") 1832 ergo_format_region("candidate old regions") 1833 ergo_format_byte_perc("reclaimable") 1834 ergo_format_perc("threshold"), 1835 cset_chooser->remaining_regions(), 1836 reclaimable_bytes, 1837 reclaimable_perc, threshold); 1838 return false; 1839 } 1840 1841 ergo_verbose4(ErgoMixedGCs, 1842 true_action_str, 1843 ergo_format_reason("candidate old regions available") 1844 ergo_format_region("candidate old regions") 1845 ergo_format_byte_perc("reclaimable") 1846 ergo_format_perc("threshold"), 1847 cset_chooser->remaining_regions(), 1848 reclaimable_bytes, 1849 reclaimable_perc, threshold); 1850 return true; 1851 } 1852 1853 uint G1CollectorPolicy::calc_min_old_cset_length() { 1854 // The min old CSet region bound is based on the maximum desired 1855 // number of mixed GCs after a cycle. I.e., even if some old regions 1856 // look expensive, we should add them to the CSet anyway to make 1857 // sure we go through the available old regions in no more than the 1858 // maximum desired number of mixed GCs. 1859 // 1860 // The calculation is based on the number of marked regions we added 1861 // to the CSet chooser in the first place, not how many remain, so 1862 // that the result is the same during all mixed GCs that follow a cycle. 1863 1864 const size_t region_num = (size_t) _collectionSetChooser->length(); 1865 const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1); 1866 size_t result = region_num / gc_num; 1867 // emulate ceiling 1868 if (result * gc_num < region_num) { 1869 result += 1; 1870 } 1871 return (uint) result; 1872 } 1873 1874 uint G1CollectorPolicy::calc_max_old_cset_length() { 1875 // The max old CSet region bound is based on the threshold expressed 1876 // as a percentage of the heap size. I.e., it should bound the 1877 // number of old regions added to the CSet irrespective of how many 1878 // of them are available. 1879 1880 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 1881 const size_t region_num = g1h->num_regions(); 1882 const size_t perc = (size_t) G1OldCSetRegionThresholdPercent; 1883 size_t result = region_num * perc / 100; 1884 // emulate ceiling 1885 if (100 * result < region_num * perc) { 1886 result += 1; 1887 } 1888 return (uint) result; 1889 } 1890 1891 1892 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info) { 1893 double young_start_time_sec = os::elapsedTime(); 1894 1895 YoungList* young_list = _g1->young_list(); 1896 finalize_incremental_cset_building(); 1897 1898 guarantee(target_pause_time_ms > 0.0, 1899 err_msg("target_pause_time_ms = %1.6lf should be positive", 1900 target_pause_time_ms)); 1901 guarantee(_collection_set == NULL, "Precondition"); 1902 1903 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards); 1904 double predicted_pause_time_ms = base_time_ms; 1905 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0); 1906 1907 ergo_verbose4(ErgoCSetConstruction | ErgoHigh, 1908 "start choosing CSet", 1909 ergo_format_size("_pending_cards") 1910 ergo_format_ms("predicted base time") 1911 ergo_format_ms("remaining time") 1912 ergo_format_ms("target pause time"), 1913 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms); 1914 1915 _last_gc_was_young = gcs_are_young() ? true : false; 1916 1917 if (_last_gc_was_young) { 1918 _trace_young_gen_time_data.increment_young_collection_count(); 1919 } else { 1920 _trace_young_gen_time_data.increment_mixed_collection_count(); 1921 } 1922 1923 // The young list is laid with the survivor regions from the previous 1924 // pause are appended to the RHS of the young list, i.e. 1925 // [Newly Young Regions ++ Survivors from last pause]. 1926 1927 uint survivor_region_length = young_list->survivor_length(); 1928 uint eden_region_length = young_list->length() - survivor_region_length; 1929 init_cset_region_lengths(eden_region_length, survivor_region_length); 1930 1931 HeapRegion* hr = young_list->first_survivor_region(); 1932 while (hr != NULL) { 1933 assert(hr->is_survivor(), "badly formed young list"); 1934 // There is a convention that all the young regions in the CSet 1935 // are tagged as "eden", so we do this for the survivors here. We 1936 // use the special set_eden_pre_gc() as it doesn't check that the 1937 // region is free (which is not the case here). 1938 hr->set_eden_pre_gc(); 1939 hr = hr->get_next_young_region(); 1940 } 1941 1942 // Clear the fields that point to the survivor list - they are all young now. 1943 young_list->clear_survivors(); 1944 1945 _collection_set = _inc_cset_head; 1946 _collection_set_bytes_used_before = _inc_cset_bytes_used_before; 1947 time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0); 1948 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms; 1949 1950 ergo_verbose3(ErgoCSetConstruction | ErgoHigh, 1951 "add young regions to CSet", 1952 ergo_format_region("eden") 1953 ergo_format_region("survivors") 1954 ergo_format_ms("predicted young region time"), 1955 eden_region_length, survivor_region_length, 1956 _inc_cset_predicted_elapsed_time_ms); 1957 1958 // The number of recorded young regions is the incremental 1959 // collection set's current size 1960 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths); 1961 1962 double young_end_time_sec = os::elapsedTime(); 1963 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0); 1964 1965 // Set the start of the non-young choice time. 1966 double non_young_start_time_sec = young_end_time_sec; 1967 1968 if (!gcs_are_young()) { 1969 CollectionSetChooser* cset_chooser = _collectionSetChooser; 1970 cset_chooser->verify(); 1971 const uint min_old_cset_length = calc_min_old_cset_length(); 1972 const uint max_old_cset_length = calc_max_old_cset_length(); 1973 1974 uint expensive_region_num = 0; 1975 bool check_time_remaining = adaptive_young_list_length(); 1976 1977 HeapRegion* hr = cset_chooser->peek(); 1978 while (hr != NULL) { 1979 if (old_cset_region_length() >= max_old_cset_length) { 1980 // Added maximum number of old regions to the CSet. 1981 ergo_verbose2(ErgoCSetConstruction, 1982 "finish adding old regions to CSet", 1983 ergo_format_reason("old CSet region num reached max") 1984 ergo_format_region("old") 1985 ergo_format_region("max"), 1986 old_cset_region_length(), max_old_cset_length); 1987 break; 1988 } 1989 1990 1991 // Stop adding regions if the remaining reclaimable space is 1992 // not above G1HeapWastePercent. 1993 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes(); 1994 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes); 1995 double threshold = (double) G1HeapWastePercent; 1996 if (reclaimable_perc <= threshold) { 1997 // We've added enough old regions that the amount of uncollected 1998 // reclaimable space is at or below the waste threshold. Stop 1999 // adding old regions to the CSet. 2000 ergo_verbose5(ErgoCSetConstruction, 2001 "finish adding old regions to CSet", 2002 ergo_format_reason("reclaimable percentage not over threshold") 2003 ergo_format_region("old") 2004 ergo_format_region("max") 2005 ergo_format_byte_perc("reclaimable") 2006 ergo_format_perc("threshold"), 2007 old_cset_region_length(), 2008 max_old_cset_length, 2009 reclaimable_bytes, 2010 reclaimable_perc, threshold); 2011 break; 2012 } 2013 2014 double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young()); 2015 if (check_time_remaining) { 2016 if (predicted_time_ms > time_remaining_ms) { 2017 // Too expensive for the current CSet. 2018 2019 if (old_cset_region_length() >= min_old_cset_length) { 2020 // We have added the minimum number of old regions to the CSet, 2021 // we are done with this CSet. 2022 ergo_verbose4(ErgoCSetConstruction, 2023 "finish adding old regions to CSet", 2024 ergo_format_reason("predicted time is too high") 2025 ergo_format_ms("predicted time") 2026 ergo_format_ms("remaining time") 2027 ergo_format_region("old") 2028 ergo_format_region("min"), 2029 predicted_time_ms, time_remaining_ms, 2030 old_cset_region_length(), min_old_cset_length); 2031 break; 2032 } 2033 2034 // We'll add it anyway given that we haven't reached the 2035 // minimum number of old regions. 2036 expensive_region_num += 1; 2037 } 2038 } else { 2039 if (old_cset_region_length() >= min_old_cset_length) { 2040 // In the non-auto-tuning case, we'll finish adding regions 2041 // to the CSet if we reach the minimum. 2042 ergo_verbose2(ErgoCSetConstruction, 2043 "finish adding old regions to CSet", 2044 ergo_format_reason("old CSet region num reached min") 2045 ergo_format_region("old") 2046 ergo_format_region("min"), 2047 old_cset_region_length(), min_old_cset_length); 2048 break; 2049 } 2050 } 2051 2052 // We will add this region to the CSet. 2053 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0); 2054 predicted_pause_time_ms += predicted_time_ms; 2055 cset_chooser->remove_and_move_to_next(hr); 2056 _g1->old_set_remove(hr); 2057 add_old_region_to_cset(hr); 2058 2059 hr = cset_chooser->peek(); 2060 } 2061 if (hr == NULL) { 2062 ergo_verbose0(ErgoCSetConstruction, 2063 "finish adding old regions to CSet", 2064 ergo_format_reason("candidate old regions not available")); 2065 } 2066 2067 if (expensive_region_num > 0) { 2068 // We print the information once here at the end, predicated on 2069 // whether we added any apparently expensive regions or not, to 2070 // avoid generating output per region. 2071 ergo_verbose4(ErgoCSetConstruction, 2072 "added expensive regions to CSet", 2073 ergo_format_reason("old CSet region num not reached min") 2074 ergo_format_region("old") 2075 ergo_format_region("expensive") 2076 ergo_format_region("min") 2077 ergo_format_ms("remaining time"), 2078 old_cset_region_length(), 2079 expensive_region_num, 2080 min_old_cset_length, 2081 time_remaining_ms); 2082 } 2083 2084 cset_chooser->verify(); 2085 } 2086 2087 stop_incremental_cset_building(); 2088 2089 ergo_verbose5(ErgoCSetConstruction, 2090 "finish choosing CSet", 2091 ergo_format_region("eden") 2092 ergo_format_region("survivors") 2093 ergo_format_region("old") 2094 ergo_format_ms("predicted pause time") 2095 ergo_format_ms("target pause time"), 2096 eden_region_length, survivor_region_length, 2097 old_cset_region_length(), 2098 predicted_pause_time_ms, target_pause_time_ms); 2099 2100 double non_young_end_time_sec = os::elapsedTime(); 2101 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0); 2102 evacuation_info.set_collectionset_regions(cset_region_length()); 2103 } 2104 2105 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) { 2106 if(TraceYoungGenTime) { 2107 _all_stop_world_times_ms.add(time_to_stop_the_world_ms); 2108 } 2109 } 2110 2111 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) { 2112 if(TraceYoungGenTime) { 2113 _all_yield_times_ms.add(yield_time_ms); 2114 } 2115 } 2116 2117 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) { 2118 if(TraceYoungGenTime) { 2119 _total.add(pause_time_ms); 2120 _other.add(pause_time_ms - phase_times->accounted_time_ms()); 2121 _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms()); 2122 _parallel.add(phase_times->cur_collection_par_time_ms()); 2123 _ext_root_scan.add(phase_times->average_time(G1GCPhaseTimes::ExtRootScan)); 2124 _satb_filtering.add(phase_times->average_time(G1GCPhaseTimes::SATBFiltering)); 2125 _update_rs.add(phase_times->average_time(G1GCPhaseTimes::UpdateRS)); 2126 _scan_rs.add(phase_times->average_time(G1GCPhaseTimes::ScanRS)); 2127 _obj_copy.add(phase_times->average_time(G1GCPhaseTimes::ObjCopy)); 2128 _termination.add(phase_times->average_time(G1GCPhaseTimes::Termination)); 2129 2130 double parallel_known_time = phase_times->average_time(G1GCPhaseTimes::ExtRootScan) + 2131 phase_times->average_time(G1GCPhaseTimes::SATBFiltering) + 2132 phase_times->average_time(G1GCPhaseTimes::UpdateRS) + 2133 phase_times->average_time(G1GCPhaseTimes::ScanRS) + 2134 phase_times->average_time(G1GCPhaseTimes::ObjCopy) + 2135 phase_times->average_time(G1GCPhaseTimes::Termination); 2136 2137 double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time; 2138 _parallel_other.add(parallel_other_time); 2139 _clear_ct.add(phase_times->cur_clear_ct_time_ms()); 2140 } 2141 } 2142 2143 void TraceYoungGenTimeData::increment_young_collection_count() { 2144 if(TraceYoungGenTime) { 2145 ++_young_pause_num; 2146 } 2147 } 2148 2149 void TraceYoungGenTimeData::increment_mixed_collection_count() { 2150 if(TraceYoungGenTime) { 2151 ++_mixed_pause_num; 2152 } 2153 } 2154 2155 void TraceYoungGenTimeData::print_summary(const char* str, 2156 const NumberSeq* seq) const { 2157 double sum = seq->sum(); 2158 gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)", 2159 str, sum / 1000.0, seq->avg()); 2160 } 2161 2162 void TraceYoungGenTimeData::print_summary_sd(const char* str, 2163 const NumberSeq* seq) const { 2164 print_summary(str, seq); 2165 gclog_or_tty->print_cr("%+45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)", 2166 "(num", seq->num(), seq->sd(), seq->maximum()); 2167 } 2168 2169 void TraceYoungGenTimeData::print() const { 2170 if (!TraceYoungGenTime) { 2171 return; 2172 } 2173 2174 gclog_or_tty->print_cr("ALL PAUSES"); 2175 print_summary_sd(" Total", &_total); 2176 gclog_or_tty->cr(); 2177 gclog_or_tty->cr(); 2178 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num); 2179 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num); 2180 gclog_or_tty->cr(); 2181 2182 gclog_or_tty->print_cr("EVACUATION PAUSES"); 2183 2184 if (_young_pause_num == 0 && _mixed_pause_num == 0) { 2185 gclog_or_tty->print_cr("none"); 2186 } else { 2187 print_summary_sd(" Evacuation Pauses", &_total); 2188 print_summary(" Root Region Scan Wait", &_root_region_scan_wait); 2189 print_summary(" Parallel Time", &_parallel); 2190 print_summary(" Ext Root Scanning", &_ext_root_scan); 2191 print_summary(" SATB Filtering", &_satb_filtering); 2192 print_summary(" Update RS", &_update_rs); 2193 print_summary(" Scan RS", &_scan_rs); 2194 print_summary(" Object Copy", &_obj_copy); 2195 print_summary(" Termination", &_termination); 2196 print_summary(" Parallel Other", &_parallel_other); 2197 print_summary(" Clear CT", &_clear_ct); 2198 print_summary(" Other", &_other); 2199 } 2200 gclog_or_tty->cr(); 2201 2202 gclog_or_tty->print_cr("MISC"); 2203 print_summary_sd(" Stop World", &_all_stop_world_times_ms); 2204 print_summary_sd(" Yields", &_all_yield_times_ms); 2205 } 2206 2207 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) { 2208 if (TraceOldGenTime) { 2209 _all_full_gc_times.add(full_gc_time_ms); 2210 } 2211 } 2212 2213 void TraceOldGenTimeData::print() const { 2214 if (!TraceOldGenTime) { 2215 return; 2216 } 2217 2218 if (_all_full_gc_times.num() > 0) { 2219 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s", 2220 _all_full_gc_times.num(), 2221 _all_full_gc_times.sum() / 1000.0); 2222 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg()); 2223 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]", 2224 _all_full_gc_times.sd(), 2225 _all_full_gc_times.maximum()); 2226 } 2227 }