1 /* 2 * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "gc_implementation/g1/concurrentG1Refine.hpp" 27 #include "gc_implementation/g1/concurrentMark.hpp" 28 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" 30 #include "gc_implementation/g1/g1CollectorPolicy.hpp" 31 #include "gc_implementation/g1/g1ErgoVerbose.hpp" 32 #include "gc_implementation/g1/g1GCPhaseTimes.hpp" 33 #include "gc_implementation/g1/g1Log.hpp" 34 #include "gc_implementation/g1/heapRegionRemSet.hpp" 35 #include "gc_implementation/shared/gcPolicyCounters.hpp" 36 #include "runtime/arguments.hpp" 37 #include "runtime/java.hpp" 38 #include "runtime/mutexLocker.hpp" 39 #include "utilities/debug.hpp" 40 41 // Different defaults for different number of GC threads 42 // They were chosen by running GCOld and SPECjbb on debris with different 43 // numbers of GC threads and choosing them based on the results 44 45 // all the same 46 static double rs_length_diff_defaults[] = { 47 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 48 }; 49 50 static double cost_per_card_ms_defaults[] = { 51 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015 52 }; 53 54 // all the same 55 static double young_cards_per_entry_ratio_defaults[] = { 56 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 57 }; 58 59 static double cost_per_entry_ms_defaults[] = { 60 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005 61 }; 62 63 static double cost_per_byte_ms_defaults[] = { 64 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009 65 }; 66 67 // these should be pretty consistent 68 static double constant_other_time_ms_defaults[] = { 69 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0 70 }; 71 72 73 static double young_other_cost_per_region_ms_defaults[] = { 74 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1 75 }; 76 77 static double non_young_other_cost_per_region_ms_defaults[] = { 78 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30 79 }; 80 81 G1CollectorPolicy::G1CollectorPolicy() : 82 _parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads() 83 ? ParallelGCThreads : 1), 84 85 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), 86 _stop_world_start(0.0), 87 88 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), 89 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), 90 91 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)), 92 _prev_collection_pause_end_ms(0.0), 93 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)), 94 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)), 95 _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)), 96 _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)), 97 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)), 98 _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)), 99 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)), 100 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)), 101 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)), 102 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)), 103 _non_young_other_cost_per_region_ms_seq( 104 new TruncatedSeq(TruncatedSeqLength)), 105 106 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)), 107 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)), 108 109 _pause_time_target_ms((double) MaxGCPauseMillis), 110 111 _gcs_are_young(true), 112 113 _during_marking(false), 114 _in_marking_window(false), 115 _in_marking_window_im(false), 116 117 _recent_prev_end_times_for_all_gcs_sec( 118 new TruncatedSeq(NumPrevPausesForHeuristics)), 119 120 _recent_avg_pause_time_ratio(0.0), 121 122 _initiate_conc_mark_if_possible(false), 123 _during_initial_mark_pause(false), 124 _last_young_gc(false), 125 _last_gc_was_young(false), 126 127 _eden_used_bytes_before_gc(0), 128 _survivor_used_bytes_before_gc(0), 129 _heap_used_bytes_before_gc(0), 130 _metaspace_used_bytes_before_gc(0), 131 _eden_capacity_bytes_before_gc(0), 132 _heap_capacity_bytes_before_gc(0), 133 134 _eden_cset_region_length(0), 135 _survivor_cset_region_length(0), 136 _old_cset_region_length(0), 137 138 _collection_set(NULL), 139 _collection_set_bytes_used_before(0), 140 141 // Incremental CSet attributes 142 _inc_cset_build_state(Inactive), 143 _inc_cset_head(NULL), 144 _inc_cset_tail(NULL), 145 _inc_cset_bytes_used_before(0), 146 _inc_cset_max_finger(NULL), 147 _inc_cset_recorded_rs_lengths(0), 148 _inc_cset_recorded_rs_lengths_diffs(0), 149 _inc_cset_predicted_elapsed_time_ms(0.0), 150 _inc_cset_predicted_elapsed_time_ms_diffs(0.0), 151 152 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away 153 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 154 #endif // _MSC_VER 155 156 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived", 157 G1YoungSurvRateNumRegionsSummary)), 158 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor", 159 G1YoungSurvRateNumRegionsSummary)), 160 // add here any more surv rate groups 161 _recorded_survivor_regions(0), 162 _recorded_survivor_head(NULL), 163 _recorded_survivor_tail(NULL), 164 _survivors_age_table(true), 165 166 _gc_overhead_perc(0.0) { 167 168 // Set up the region size and associated fields. Given that the 169 // policy is created before the heap, we have to set this up here, 170 // so it's done as soon as possible. 171 172 // It would have been natural to pass initial_heap_byte_size() and 173 // max_heap_byte_size() to setup_heap_region_size() but those have 174 // not been set up at this point since they should be aligned with 175 // the region size. So, there is a circular dependency here. We base 176 // the region size on the heap size, but the heap size should be 177 // aligned with the region size. To get around this we use the 178 // unaligned values for the heap. 179 HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize); 180 HeapRegionRemSet::setup_remset_size(); 181 182 G1ErgoVerbose::initialize(); 183 if (PrintAdaptiveSizePolicy) { 184 // Currently, we only use a single switch for all the heuristics. 185 G1ErgoVerbose::set_enabled(true); 186 // Given that we don't currently have a verboseness level 187 // parameter, we'll hardcode this to high. This can be easily 188 // changed in the future. 189 G1ErgoVerbose::set_level(ErgoHigh); 190 } else { 191 G1ErgoVerbose::set_enabled(false); 192 } 193 194 // Verify PLAB sizes 195 const size_t region_size = HeapRegion::GrainWords; 196 if (YoungPLABSize > region_size || OldPLABSize > region_size) { 197 char buffer[128]; 198 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT, 199 OldPLABSize > region_size ? "Old" : "Young", region_size); 200 vm_exit_during_initialization(buffer); 201 } 202 203 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime()); 204 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0; 205 206 _phase_times = new G1GCPhaseTimes(_parallel_gc_threads); 207 208 int index = MIN2(_parallel_gc_threads - 1, 7); 209 210 _rs_length_diff_seq->add(rs_length_diff_defaults[index]); 211 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]); 212 _young_cards_per_entry_ratio_seq->add( 213 young_cards_per_entry_ratio_defaults[index]); 214 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]); 215 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]); 216 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]); 217 _young_other_cost_per_region_ms_seq->add( 218 young_other_cost_per_region_ms_defaults[index]); 219 _non_young_other_cost_per_region_ms_seq->add( 220 non_young_other_cost_per_region_ms_defaults[index]); 221 222 // Below, we might need to calculate the pause time target based on 223 // the pause interval. When we do so we are going to give G1 maximum 224 // flexibility and allow it to do pauses when it needs to. So, we'll 225 // arrange that the pause interval to be pause time target + 1 to 226 // ensure that a) the pause time target is maximized with respect to 227 // the pause interval and b) we maintain the invariant that pause 228 // time target < pause interval. If the user does not want this 229 // maximum flexibility, they will have to set the pause interval 230 // explicitly. 231 232 // First make sure that, if either parameter is set, its value is 233 // reasonable. 234 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) { 235 if (MaxGCPauseMillis < 1) { 236 vm_exit_during_initialization("MaxGCPauseMillis should be " 237 "greater than 0"); 238 } 239 } 240 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { 241 if (GCPauseIntervalMillis < 1) { 242 vm_exit_during_initialization("GCPauseIntervalMillis should be " 243 "greater than 0"); 244 } 245 } 246 247 // Then, if the pause time target parameter was not set, set it to 248 // the default value. 249 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) { 250 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { 251 // The default pause time target in G1 is 200ms 252 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200); 253 } else { 254 // We do not allow the pause interval to be set without the 255 // pause time target 256 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set " 257 "without setting MaxGCPauseMillis"); 258 } 259 } 260 261 // Then, if the interval parameter was not set, set it according to 262 // the pause time target (this will also deal with the case when the 263 // pause time target is the default value). 264 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { 265 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1); 266 } 267 268 // Finally, make sure that the two parameters are consistent. 269 if (MaxGCPauseMillis >= GCPauseIntervalMillis) { 270 char buffer[256]; 271 jio_snprintf(buffer, 256, 272 "MaxGCPauseMillis (%u) should be less than " 273 "GCPauseIntervalMillis (%u)", 274 MaxGCPauseMillis, GCPauseIntervalMillis); 275 vm_exit_during_initialization(buffer); 276 } 277 278 double max_gc_time = (double) MaxGCPauseMillis / 1000.0; 279 double time_slice = (double) GCPauseIntervalMillis / 1000.0; 280 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time); 281 282 uintx confidence_perc = G1ConfidencePercent; 283 // Put an artificial ceiling on this so that it's not set to a silly value. 284 if (confidence_perc > 100) { 285 confidence_perc = 100; 286 warning("G1ConfidencePercent is set to a value that is too large, " 287 "it's been updated to %u", confidence_perc); 288 } 289 _sigma = (double) confidence_perc / 100.0; 290 291 // start conservatively (around 50ms is about right) 292 _concurrent_mark_remark_times_ms->add(0.05); 293 _concurrent_mark_cleanup_times_ms->add(0.20); 294 _tenuring_threshold = MaxTenuringThreshold; 295 // _max_survivor_regions will be calculated by 296 // update_young_list_target_length() during initialization. 297 _max_survivor_regions = 0; 298 299 assert(GCTimeRatio > 0, 300 "we should have set it to a default value set_g1_gc_flags() " 301 "if a user set it to 0"); 302 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio)); 303 304 uintx reserve_perc = G1ReservePercent; 305 // Put an artificial ceiling on this so that it's not set to a silly value. 306 if (reserve_perc > 50) { 307 reserve_perc = 50; 308 warning("G1ReservePercent is set to a value that is too large, " 309 "it's been updated to %u", reserve_perc); 310 } 311 _reserve_factor = (double) reserve_perc / 100.0; 312 // This will be set when the heap is expanded 313 // for the first time during initialization. 314 _reserve_regions = 0; 315 316 _collectionSetChooser = new CollectionSetChooser(); 317 } 318 319 void G1CollectorPolicy::initialize_alignments() { 320 _space_alignment = HeapRegion::GrainBytes; 321 size_t card_table_alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable); 322 size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size(); 323 _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size); 324 } 325 326 void G1CollectorPolicy::initialize_flags() { 327 if (G1HeapRegionSize != HeapRegion::GrainBytes) { 328 FLAG_SET_ERGO(uintx, G1HeapRegionSize, HeapRegion::GrainBytes); 329 } 330 331 if (SurvivorRatio < 1) { 332 vm_exit_during_initialization("Invalid survivor ratio specified"); 333 } 334 CollectorPolicy::initialize_flags(); 335 _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags 336 } 337 338 void G1CollectorPolicy::post_heap_initialize() { 339 uintx max_regions = G1CollectedHeap::heap()->max_regions(); 340 size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes; 341 if (max_young_size != MaxNewSize) { 342 FLAG_SET_ERGO(uintx, MaxNewSize, max_young_size); 343 } 344 } 345 346 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true), 347 _min_desired_young_length(0), _max_desired_young_length(0) { 348 if (FLAG_IS_CMDLINE(NewRatio)) { 349 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) { 350 warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio"); 351 } else { 352 _sizer_kind = SizerNewRatio; 353 _adaptive_size = false; 354 return; 355 } 356 } 357 358 if (FLAG_IS_CMDLINE(NewSize) && FLAG_IS_CMDLINE(MaxNewSize) && NewSize > MaxNewSize) { 359 vm_exit_during_initialization("Initial young gen size set larger than the maximum young gen size"); 360 } 361 362 if (FLAG_IS_CMDLINE(NewSize)) { 363 _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes), 364 1U); 365 if (FLAG_IS_CMDLINE(MaxNewSize)) { 366 _max_desired_young_length = 367 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes), 368 1U); 369 _sizer_kind = SizerMaxAndNewSize; 370 _adaptive_size = _min_desired_young_length == _max_desired_young_length; 371 } else { 372 _sizer_kind = SizerNewSizeOnly; 373 } 374 } else if (FLAG_IS_CMDLINE(MaxNewSize)) { 375 _max_desired_young_length = 376 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes), 377 1U); 378 _sizer_kind = SizerMaxNewSizeOnly; 379 } 380 } 381 382 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) { 383 uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100; 384 return MAX2(1U, default_value); 385 } 386 387 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) { 388 uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100; 389 return MAX2(1U, default_value); 390 } 391 392 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) { 393 assert(number_of_heap_regions > 0, "Heap must be initialized"); 394 395 switch (_sizer_kind) { 396 case SizerDefaults: 397 *min_young_length = calculate_default_min_length(number_of_heap_regions); 398 *max_young_length = calculate_default_max_length(number_of_heap_regions); 399 break; 400 case SizerNewSizeOnly: 401 *max_young_length = calculate_default_max_length(number_of_heap_regions); 402 *max_young_length = MAX2(*min_young_length, *max_young_length); 403 break; 404 case SizerMaxNewSizeOnly: 405 *min_young_length = calculate_default_min_length(number_of_heap_regions); 406 *min_young_length = MIN2(*min_young_length, *max_young_length); 407 break; 408 case SizerMaxAndNewSize: 409 // Do nothing. Values set on the command line, don't update them at runtime. 410 break; 411 case SizerNewRatio: 412 *min_young_length = number_of_heap_regions / (NewRatio + 1); 413 *max_young_length = *min_young_length; 414 break; 415 default: 416 ShouldNotReachHere(); 417 } 418 419 assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values"); 420 } 421 422 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) { 423 // We need to pass the desired values because recalculation may not update these 424 // values in some cases. 425 uint temp = _min_desired_young_length; 426 uint result = _max_desired_young_length; 427 recalculate_min_max_young_length(number_of_heap_regions, &temp, &result); 428 return result; 429 } 430 431 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) { 432 recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length, 433 &_max_desired_young_length); 434 } 435 436 void G1CollectorPolicy::init() { 437 // Set aside an initial future to_space. 438 _g1 = G1CollectedHeap::heap(); 439 440 assert(Heap_lock->owned_by_self(), "Locking discipline."); 441 442 initialize_gc_policy_counters(); 443 444 if (adaptive_young_list_length()) { 445 _young_list_fixed_length = 0; 446 } else { 447 _young_list_fixed_length = _young_gen_sizer->min_desired_young_length(); 448 } 449 _free_regions_at_end_of_collection = _g1->free_regions(); 450 update_young_list_target_length(); 451 452 // We may immediately start allocating regions and placing them on the 453 // collection set list. Initialize the per-collection set info 454 start_incremental_cset_building(); 455 } 456 457 // Create the jstat counters for the policy. 458 void G1CollectorPolicy::initialize_gc_policy_counters() { 459 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3); 460 } 461 462 bool G1CollectorPolicy::predict_will_fit(uint young_length, 463 double base_time_ms, 464 uint base_free_regions, 465 double target_pause_time_ms) { 466 if (young_length >= base_free_regions) { 467 // end condition 1: not enough space for the young regions 468 return false; 469 } 470 471 double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1); 472 size_t bytes_to_copy = 473 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes); 474 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy); 475 double young_other_time_ms = predict_young_other_time_ms(young_length); 476 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms; 477 if (pause_time_ms > target_pause_time_ms) { 478 // end condition 2: prediction is over the target pause time 479 return false; 480 } 481 482 size_t free_bytes = 483 (base_free_regions - young_length) * HeapRegion::GrainBytes; 484 if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) { 485 // end condition 3: out-of-space (conservatively!) 486 return false; 487 } 488 489 // success! 490 return true; 491 } 492 493 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) { 494 // re-calculate the necessary reserve 495 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor; 496 // We use ceiling so that if reserve_regions_d is > 0.0 (but 497 // smaller than 1.0) we'll get 1. 498 _reserve_regions = (uint) ceil(reserve_regions_d); 499 500 _young_gen_sizer->heap_size_changed(new_number_of_regions); 501 } 502 503 uint G1CollectorPolicy::calculate_young_list_desired_min_length( 504 uint base_min_length) { 505 uint desired_min_length = 0; 506 if (adaptive_young_list_length()) { 507 if (_alloc_rate_ms_seq->num() > 3) { 508 double now_sec = os::elapsedTime(); 509 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0; 510 double alloc_rate_ms = predict_alloc_rate_ms(); 511 desired_min_length = (uint) ceil(alloc_rate_ms * when_ms); 512 } else { 513 // otherwise we don't have enough info to make the prediction 514 } 515 } 516 desired_min_length += base_min_length; 517 // make sure we don't go below any user-defined minimum bound 518 return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length); 519 } 520 521 uint G1CollectorPolicy::calculate_young_list_desired_max_length() { 522 // Here, we might want to also take into account any additional 523 // constraints (i.e., user-defined minimum bound). Currently, we 524 // effectively don't set this bound. 525 return _young_gen_sizer->max_desired_young_length(); 526 } 527 528 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) { 529 if (rs_lengths == (size_t) -1) { 530 // if it's set to the default value (-1), we should predict it; 531 // otherwise, use the given value. 532 rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq); 533 } 534 535 // Calculate the absolute and desired min bounds. 536 537 // This is how many young regions we already have (currently: the survivors). 538 uint base_min_length = recorded_survivor_regions(); 539 // This is the absolute minimum young length, which ensures that we 540 // can allocate one eden region in the worst-case. 541 uint absolute_min_length = base_min_length + 1; 542 uint desired_min_length = 543 calculate_young_list_desired_min_length(base_min_length); 544 if (desired_min_length < absolute_min_length) { 545 desired_min_length = absolute_min_length; 546 } 547 548 // Calculate the absolute and desired max bounds. 549 550 // We will try our best not to "eat" into the reserve. 551 uint absolute_max_length = 0; 552 if (_free_regions_at_end_of_collection > _reserve_regions) { 553 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions; 554 } 555 uint desired_max_length = calculate_young_list_desired_max_length(); 556 if (desired_max_length > absolute_max_length) { 557 desired_max_length = absolute_max_length; 558 } 559 560 uint young_list_target_length = 0; 561 if (adaptive_young_list_length()) { 562 if (gcs_are_young()) { 563 young_list_target_length = 564 calculate_young_list_target_length(rs_lengths, 565 base_min_length, 566 desired_min_length, 567 desired_max_length); 568 _rs_lengths_prediction = rs_lengths; 569 } else { 570 // Don't calculate anything and let the code below bound it to 571 // the desired_min_length, i.e., do the next GC as soon as 572 // possible to maximize how many old regions we can add to it. 573 } 574 } else { 575 // The user asked for a fixed young gen so we'll fix the young gen 576 // whether the next GC is young or mixed. 577 young_list_target_length = _young_list_fixed_length; 578 } 579 580 // Make sure we don't go over the desired max length, nor under the 581 // desired min length. In case they clash, desired_min_length wins 582 // which is why that test is second. 583 if (young_list_target_length > desired_max_length) { 584 young_list_target_length = desired_max_length; 585 } 586 if (young_list_target_length < desired_min_length) { 587 young_list_target_length = desired_min_length; 588 } 589 590 assert(young_list_target_length > recorded_survivor_regions(), 591 "we should be able to allocate at least one eden region"); 592 assert(young_list_target_length >= absolute_min_length, "post-condition"); 593 _young_list_target_length = young_list_target_length; 594 595 update_max_gc_locker_expansion(); 596 } 597 598 uint 599 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths, 600 uint base_min_length, 601 uint desired_min_length, 602 uint desired_max_length) { 603 assert(adaptive_young_list_length(), "pre-condition"); 604 assert(gcs_are_young(), "only call this for young GCs"); 605 606 // In case some edge-condition makes the desired max length too small... 607 if (desired_max_length <= desired_min_length) { 608 return desired_min_length; 609 } 610 611 // We'll adjust min_young_length and max_young_length not to include 612 // the already allocated young regions (i.e., so they reflect the 613 // min and max eden regions we'll allocate). The base_min_length 614 // will be reflected in the predictions by the 615 // survivor_regions_evac_time prediction. 616 assert(desired_min_length > base_min_length, "invariant"); 617 uint min_young_length = desired_min_length - base_min_length; 618 assert(desired_max_length > base_min_length, "invariant"); 619 uint max_young_length = desired_max_length - base_min_length; 620 621 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0; 622 double survivor_regions_evac_time = predict_survivor_regions_evac_time(); 623 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq); 624 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff(); 625 size_t scanned_cards = predict_young_card_num(adj_rs_lengths); 626 double base_time_ms = 627 predict_base_elapsed_time_ms(pending_cards, scanned_cards) + 628 survivor_regions_evac_time; 629 uint available_free_regions = _free_regions_at_end_of_collection; 630 uint base_free_regions = 0; 631 if (available_free_regions > _reserve_regions) { 632 base_free_regions = available_free_regions - _reserve_regions; 633 } 634 635 // Here, we will make sure that the shortest young length that 636 // makes sense fits within the target pause time. 637 638 if (predict_will_fit(min_young_length, base_time_ms, 639 base_free_regions, target_pause_time_ms)) { 640 // The shortest young length will fit into the target pause time; 641 // we'll now check whether the absolute maximum number of young 642 // regions will fit in the target pause time. If not, we'll do 643 // a binary search between min_young_length and max_young_length. 644 if (predict_will_fit(max_young_length, base_time_ms, 645 base_free_regions, target_pause_time_ms)) { 646 // The maximum young length will fit into the target pause time. 647 // We are done so set min young length to the maximum length (as 648 // the result is assumed to be returned in min_young_length). 649 min_young_length = max_young_length; 650 } else { 651 // The maximum possible number of young regions will not fit within 652 // the target pause time so we'll search for the optimal 653 // length. The loop invariants are: 654 // 655 // min_young_length < max_young_length 656 // min_young_length is known to fit into the target pause time 657 // max_young_length is known not to fit into the target pause time 658 // 659 // Going into the loop we know the above hold as we've just 660 // checked them. Every time around the loop we check whether 661 // the middle value between min_young_length and 662 // max_young_length fits into the target pause time. If it 663 // does, it becomes the new min. If it doesn't, it becomes 664 // the new max. This way we maintain the loop invariants. 665 666 assert(min_young_length < max_young_length, "invariant"); 667 uint diff = (max_young_length - min_young_length) / 2; 668 while (diff > 0) { 669 uint young_length = min_young_length + diff; 670 if (predict_will_fit(young_length, base_time_ms, 671 base_free_regions, target_pause_time_ms)) { 672 min_young_length = young_length; 673 } else { 674 max_young_length = young_length; 675 } 676 assert(min_young_length < max_young_length, "invariant"); 677 diff = (max_young_length - min_young_length) / 2; 678 } 679 // The results is min_young_length which, according to the 680 // loop invariants, should fit within the target pause time. 681 682 // These are the post-conditions of the binary search above: 683 assert(min_young_length < max_young_length, 684 "otherwise we should have discovered that max_young_length " 685 "fits into the pause target and not done the binary search"); 686 assert(predict_will_fit(min_young_length, base_time_ms, 687 base_free_regions, target_pause_time_ms), 688 "min_young_length, the result of the binary search, should " 689 "fit into the pause target"); 690 assert(!predict_will_fit(min_young_length + 1, base_time_ms, 691 base_free_regions, target_pause_time_ms), 692 "min_young_length, the result of the binary search, should be " 693 "optimal, so no larger length should fit into the pause target"); 694 } 695 } else { 696 // Even the minimum length doesn't fit into the pause time 697 // target, return it as the result nevertheless. 698 } 699 return base_min_length + min_young_length; 700 } 701 702 double G1CollectorPolicy::predict_survivor_regions_evac_time() { 703 double survivor_regions_evac_time = 0.0; 704 for (HeapRegion * r = _recorded_survivor_head; 705 r != NULL && r != _recorded_survivor_tail->get_next_young_region(); 706 r = r->get_next_young_region()) { 707 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young()); 708 } 709 return survivor_regions_evac_time; 710 } 711 712 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() { 713 guarantee( adaptive_young_list_length(), "should not call this otherwise" ); 714 715 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths(); 716 if (rs_lengths > _rs_lengths_prediction) { 717 // add 10% to avoid having to recalculate often 718 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000; 719 update_young_list_target_length(rs_lengths_prediction); 720 } 721 } 722 723 724 725 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size, 726 bool is_tlab, 727 bool* gc_overhead_limit_was_exceeded) { 728 guarantee(false, "Not using this policy feature yet."); 729 return NULL; 730 } 731 732 // This method controls how a collector handles one or more 733 // of its generations being fully allocated. 734 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size, 735 bool is_tlab) { 736 guarantee(false, "Not using this policy feature yet."); 737 return NULL; 738 } 739 740 741 #ifndef PRODUCT 742 bool G1CollectorPolicy::verify_young_ages() { 743 HeapRegion* head = _g1->young_list()->first_region(); 744 return 745 verify_young_ages(head, _short_lived_surv_rate_group); 746 // also call verify_young_ages on any additional surv rate groups 747 } 748 749 bool 750 G1CollectorPolicy::verify_young_ages(HeapRegion* head, 751 SurvRateGroup *surv_rate_group) { 752 guarantee( surv_rate_group != NULL, "pre-condition" ); 753 754 const char* name = surv_rate_group->name(); 755 bool ret = true; 756 int prev_age = -1; 757 758 for (HeapRegion* curr = head; 759 curr != NULL; 760 curr = curr->get_next_young_region()) { 761 SurvRateGroup* group = curr->surv_rate_group(); 762 if (group == NULL && !curr->is_survivor()) { 763 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name); 764 ret = false; 765 } 766 767 if (surv_rate_group == group) { 768 int age = curr->age_in_surv_rate_group(); 769 770 if (age < 0) { 771 gclog_or_tty->print_cr("## %s: encountered negative age", name); 772 ret = false; 773 } 774 775 if (age <= prev_age) { 776 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing " 777 "(%d, %d)", name, age, prev_age); 778 ret = false; 779 } 780 prev_age = age; 781 } 782 } 783 784 return ret; 785 } 786 #endif // PRODUCT 787 788 void G1CollectorPolicy::record_full_collection_start() { 789 _full_collection_start_sec = os::elapsedTime(); 790 record_heap_size_info_at_start(true /* full */); 791 // Release the future to-space so that it is available for compaction into. 792 _g1->set_full_collection(); 793 } 794 795 void G1CollectorPolicy::record_full_collection_end() { 796 // Consider this like a collection pause for the purposes of allocation 797 // since last pause. 798 double end_sec = os::elapsedTime(); 799 double full_gc_time_sec = end_sec - _full_collection_start_sec; 800 double full_gc_time_ms = full_gc_time_sec * 1000.0; 801 802 _trace_gen1_time_data.record_full_collection(full_gc_time_ms); 803 804 update_recent_gc_times(end_sec, full_gc_time_ms); 805 806 _g1->clear_full_collection(); 807 808 // "Nuke" the heuristics that control the young/mixed GC 809 // transitions and make sure we start with young GCs after the Full GC. 810 set_gcs_are_young(true); 811 _last_young_gc = false; 812 clear_initiate_conc_mark_if_possible(); 813 clear_during_initial_mark_pause(); 814 _in_marking_window = false; 815 _in_marking_window_im = false; 816 817 _short_lived_surv_rate_group->start_adding_regions(); 818 // also call this on any additional surv rate groups 819 820 record_survivor_regions(0, NULL, NULL); 821 822 _free_regions_at_end_of_collection = _g1->free_regions(); 823 // Reset survivors SurvRateGroup. 824 _survivor_surv_rate_group->reset(); 825 update_young_list_target_length(); 826 _collectionSetChooser->clear(); 827 } 828 829 void G1CollectorPolicy::record_stop_world_start() { 830 _stop_world_start = os::elapsedTime(); 831 } 832 833 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) { 834 // We only need to do this here as the policy will only be applied 835 // to the GC we're about to start. so, no point is calculating this 836 // every time we calculate / recalculate the target young length. 837 update_survivors_policy(); 838 839 assert(_g1->used() == _g1->recalculate_used(), 840 err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT, 841 _g1->used(), _g1->recalculate_used())); 842 843 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0; 844 _trace_gen0_time_data.record_start_collection(s_w_t_ms); 845 _stop_world_start = 0.0; 846 847 record_heap_size_info_at_start(false /* full */); 848 849 phase_times()->record_cur_collection_start_sec(start_time_sec); 850 _pending_cards = _g1->pending_card_num(); 851 852 _collection_set_bytes_used_before = 0; 853 _bytes_copied_during_gc = 0; 854 855 _last_gc_was_young = false; 856 857 // do that for any other surv rate groups 858 _short_lived_surv_rate_group->stop_adding_regions(); 859 _survivors_age_table.clear(); 860 861 assert( verify_young_ages(), "region age verification" ); 862 } 863 864 void G1CollectorPolicy::record_concurrent_mark_init_end(double 865 mark_init_elapsed_time_ms) { 866 _during_marking = true; 867 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now"); 868 clear_during_initial_mark_pause(); 869 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms; 870 } 871 872 void G1CollectorPolicy::record_concurrent_mark_remark_start() { 873 _mark_remark_start_sec = os::elapsedTime(); 874 _during_marking = false; 875 } 876 877 void G1CollectorPolicy::record_concurrent_mark_remark_end() { 878 double end_time_sec = os::elapsedTime(); 879 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0; 880 _concurrent_mark_remark_times_ms->add(elapsed_time_ms); 881 _cur_mark_stop_world_time_ms += elapsed_time_ms; 882 _prev_collection_pause_end_ms += elapsed_time_ms; 883 884 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true); 885 } 886 887 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() { 888 _mark_cleanup_start_sec = os::elapsedTime(); 889 } 890 891 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() { 892 _last_young_gc = true; 893 _in_marking_window = false; 894 } 895 896 void G1CollectorPolicy::record_concurrent_pause() { 897 if (_stop_world_start > 0.0) { 898 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0; 899 _trace_gen0_time_data.record_yield_time(yield_ms); 900 } 901 } 902 903 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) { 904 if (_g1->concurrent_mark()->cmThread()->during_cycle()) { 905 return false; 906 } 907 908 size_t marking_initiating_used_threshold = 909 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent; 910 size_t cur_used_bytes = _g1->non_young_capacity_bytes(); 911 size_t alloc_byte_size = alloc_word_size * HeapWordSize; 912 913 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) { 914 if (gcs_are_young() && !_last_young_gc) { 915 ergo_verbose5(ErgoConcCycles, 916 "request concurrent cycle initiation", 917 ergo_format_reason("occupancy higher than threshold") 918 ergo_format_byte("occupancy") 919 ergo_format_byte("allocation request") 920 ergo_format_byte_perc("threshold") 921 ergo_format_str("source"), 922 cur_used_bytes, 923 alloc_byte_size, 924 marking_initiating_used_threshold, 925 (double) InitiatingHeapOccupancyPercent, 926 source); 927 return true; 928 } else { 929 ergo_verbose5(ErgoConcCycles, 930 "do not request concurrent cycle initiation", 931 ergo_format_reason("still doing mixed collections") 932 ergo_format_byte("occupancy") 933 ergo_format_byte("allocation request") 934 ergo_format_byte_perc("threshold") 935 ergo_format_str("source"), 936 cur_used_bytes, 937 alloc_byte_size, 938 marking_initiating_used_threshold, 939 (double) InitiatingHeapOccupancyPercent, 940 source); 941 } 942 } 943 944 return false; 945 } 946 947 // Anything below that is considered to be zero 948 #define MIN_TIMER_GRANULARITY 0.0000001 949 950 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info) { 951 double end_time_sec = os::elapsedTime(); 952 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(), 953 "otherwise, the subtraction below does not make sense"); 954 size_t rs_size = 955 _cur_collection_pause_used_regions_at_start - cset_region_length(); 956 size_t cur_used_bytes = _g1->used(); 957 assert(cur_used_bytes == _g1->recalculate_used(), "It should!"); 958 bool last_pause_included_initial_mark = false; 959 bool update_stats = !_g1->evacuation_failed(); 960 961 #ifndef PRODUCT 962 if (G1YoungSurvRateVerbose) { 963 gclog_or_tty->print_cr(""); 964 _short_lived_surv_rate_group->print(); 965 // do that for any other surv rate groups too 966 } 967 #endif // PRODUCT 968 969 last_pause_included_initial_mark = during_initial_mark_pause(); 970 if (last_pause_included_initial_mark) { 971 record_concurrent_mark_init_end(0.0); 972 } else if (need_to_start_conc_mark("end of GC")) { 973 // Note: this might have already been set, if during the last 974 // pause we decided to start a cycle but at the beginning of 975 // this pause we decided to postpone it. That's OK. 976 set_initiate_conc_mark_if_possible(); 977 } 978 979 _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0, 980 end_time_sec, false); 981 982 evacuation_info.set_collectionset_used_before(_collection_set_bytes_used_before); 983 evacuation_info.set_bytes_copied(_bytes_copied_during_gc); 984 985 if (update_stats) { 986 _trace_gen0_time_data.record_end_collection(pause_time_ms, phase_times()); 987 // this is where we update the allocation rate of the application 988 double app_time_ms = 989 (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms); 990 if (app_time_ms < MIN_TIMER_GRANULARITY) { 991 // This usually happens due to the timer not having the required 992 // granularity. Some Linuxes are the usual culprits. 993 // We'll just set it to something (arbitrarily) small. 994 app_time_ms = 1.0; 995 } 996 // We maintain the invariant that all objects allocated by mutator 997 // threads will be allocated out of eden regions. So, we can use 998 // the eden region number allocated since the previous GC to 999 // calculate the application's allocate rate. The only exception 1000 // to that is humongous objects that are allocated separately. But 1001 // given that humongous object allocations do not really affect 1002 // either the pause's duration nor when the next pause will take 1003 // place we can safely ignore them here. 1004 uint regions_allocated = eden_cset_region_length(); 1005 double alloc_rate_ms = (double) regions_allocated / app_time_ms; 1006 _alloc_rate_ms_seq->add(alloc_rate_ms); 1007 1008 double interval_ms = 1009 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0; 1010 update_recent_gc_times(end_time_sec, pause_time_ms); 1011 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms; 1012 if (recent_avg_pause_time_ratio() < 0.0 || 1013 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) { 1014 #ifndef PRODUCT 1015 // Dump info to allow post-facto debugging 1016 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds"); 1017 gclog_or_tty->print_cr("-------------------------------------------"); 1018 gclog_or_tty->print_cr("Recent GC Times (ms):"); 1019 _recent_gc_times_ms->dump(); 1020 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec); 1021 _recent_prev_end_times_for_all_gcs_sec->dump(); 1022 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f", 1023 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio()); 1024 // In debug mode, terminate the JVM if the user wants to debug at this point. 1025 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above"); 1026 #endif // !PRODUCT 1027 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in 1028 // CR 6902692 by redoing the manner in which the ratio is incrementally computed. 1029 if (_recent_avg_pause_time_ratio < 0.0) { 1030 _recent_avg_pause_time_ratio = 0.0; 1031 } else { 1032 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant"); 1033 _recent_avg_pause_time_ratio = 1.0; 1034 } 1035 } 1036 } 1037 1038 bool new_in_marking_window = _in_marking_window; 1039 bool new_in_marking_window_im = false; 1040 if (during_initial_mark_pause()) { 1041 new_in_marking_window = true; 1042 new_in_marking_window_im = true; 1043 } 1044 1045 if (_last_young_gc) { 1046 // This is supposed to to be the "last young GC" before we start 1047 // doing mixed GCs. Here we decide whether to start mixed GCs or not. 1048 1049 if (!last_pause_included_initial_mark) { 1050 if (next_gc_should_be_mixed("start mixed GCs", 1051 "do not start mixed GCs")) { 1052 set_gcs_are_young(false); 1053 } 1054 } else { 1055 ergo_verbose0(ErgoMixedGCs, 1056 "do not start mixed GCs", 1057 ergo_format_reason("concurrent cycle is about to start")); 1058 } 1059 _last_young_gc = false; 1060 } 1061 1062 if (!_last_gc_was_young) { 1063 // This is a mixed GC. Here we decide whether to continue doing 1064 // mixed GCs or not. 1065 1066 if (!next_gc_should_be_mixed("continue mixed GCs", 1067 "do not continue mixed GCs")) { 1068 set_gcs_are_young(true); 1069 } 1070 } 1071 1072 _short_lived_surv_rate_group->start_adding_regions(); 1073 // do that for any other surv rate groupsx 1074 1075 if (update_stats) { 1076 double cost_per_card_ms = 0.0; 1077 if (_pending_cards > 0) { 1078 cost_per_card_ms = phase_times()->average_last_update_rs_time() / (double) _pending_cards; 1079 _cost_per_card_ms_seq->add(cost_per_card_ms); 1080 } 1081 1082 size_t cards_scanned = _g1->cards_scanned(); 1083 1084 double cost_per_entry_ms = 0.0; 1085 if (cards_scanned > 10) { 1086 cost_per_entry_ms = phase_times()->average_last_scan_rs_time() / (double) cards_scanned; 1087 if (_last_gc_was_young) { 1088 _cost_per_entry_ms_seq->add(cost_per_entry_ms); 1089 } else { 1090 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms); 1091 } 1092 } 1093 1094 if (_max_rs_lengths > 0) { 1095 double cards_per_entry_ratio = 1096 (double) cards_scanned / (double) _max_rs_lengths; 1097 if (_last_gc_was_young) { 1098 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio); 1099 } else { 1100 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio); 1101 } 1102 } 1103 1104 // This is defensive. For a while _max_rs_lengths could get 1105 // smaller than _recorded_rs_lengths which was causing 1106 // rs_length_diff to get very large and mess up the RSet length 1107 // predictions. The reason was unsafe concurrent updates to the 1108 // _inc_cset_recorded_rs_lengths field which the code below guards 1109 // against (see CR 7118202). This bug has now been fixed (see CR 1110 // 7119027). However, I'm still worried that 1111 // _inc_cset_recorded_rs_lengths might still end up somewhat 1112 // inaccurate. The concurrent refinement thread calculates an 1113 // RSet's length concurrently with other CR threads updating it 1114 // which might cause it to calculate the length incorrectly (if, 1115 // say, it's in mid-coarsening). So I'll leave in the defensive 1116 // conditional below just in case. 1117 size_t rs_length_diff = 0; 1118 if (_max_rs_lengths > _recorded_rs_lengths) { 1119 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths; 1120 } 1121 _rs_length_diff_seq->add((double) rs_length_diff); 1122 1123 size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes; 1124 size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes; 1125 double cost_per_byte_ms = 0.0; 1126 1127 if (copied_bytes > 0) { 1128 cost_per_byte_ms = phase_times()->average_last_obj_copy_time() / (double) copied_bytes; 1129 if (_in_marking_window) { 1130 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms); 1131 } else { 1132 _cost_per_byte_ms_seq->add(cost_per_byte_ms); 1133 } 1134 } 1135 1136 double all_other_time_ms = pause_time_ms - 1137 (phase_times()->average_last_update_rs_time() + phase_times()->average_last_scan_rs_time() 1138 + phase_times()->average_last_obj_copy_time() + phase_times()->average_last_termination_time()); 1139 1140 double young_other_time_ms = 0.0; 1141 if (young_cset_region_length() > 0) { 1142 young_other_time_ms = 1143 phase_times()->young_cset_choice_time_ms() + 1144 phase_times()->young_free_cset_time_ms(); 1145 _young_other_cost_per_region_ms_seq->add(young_other_time_ms / 1146 (double) young_cset_region_length()); 1147 } 1148 double non_young_other_time_ms = 0.0; 1149 if (old_cset_region_length() > 0) { 1150 non_young_other_time_ms = 1151 phase_times()->non_young_cset_choice_time_ms() + 1152 phase_times()->non_young_free_cset_time_ms(); 1153 1154 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms / 1155 (double) old_cset_region_length()); 1156 } 1157 1158 double constant_other_time_ms = all_other_time_ms - 1159 (young_other_time_ms + non_young_other_time_ms); 1160 _constant_other_time_ms_seq->add(constant_other_time_ms); 1161 1162 double survival_ratio = 0.0; 1163 if (_collection_set_bytes_used_before > 0) { 1164 survival_ratio = (double) _bytes_copied_during_gc / 1165 (double) _collection_set_bytes_used_before; 1166 } 1167 1168 _pending_cards_seq->add((double) _pending_cards); 1169 _rs_lengths_seq->add((double) _max_rs_lengths); 1170 } 1171 1172 _in_marking_window = new_in_marking_window; 1173 _in_marking_window_im = new_in_marking_window_im; 1174 _free_regions_at_end_of_collection = _g1->free_regions(); 1175 update_young_list_target_length(); 1176 1177 // Note that _mmu_tracker->max_gc_time() returns the time in seconds. 1178 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0; 1179 adjust_concurrent_refinement(phase_times()->average_last_update_rs_time(), 1180 phase_times()->sum_last_update_rs_processed_buffers(), update_rs_time_goal_ms); 1181 1182 _collectionSetChooser->verify(); 1183 } 1184 1185 #define EXT_SIZE_FORMAT "%.1f%s" 1186 #define EXT_SIZE_PARAMS(bytes) \ 1187 byte_size_in_proper_unit((double)(bytes)), \ 1188 proper_unit_for_byte_size((bytes)) 1189 1190 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) { 1191 YoungList* young_list = _g1->young_list(); 1192 _eden_used_bytes_before_gc = young_list->eden_used_bytes(); 1193 _survivor_used_bytes_before_gc = young_list->survivor_used_bytes(); 1194 _heap_capacity_bytes_before_gc = _g1->capacity(); 1195 _heap_used_bytes_before_gc = _g1->used(); 1196 _cur_collection_pause_used_regions_at_start = _g1->used_regions(); 1197 1198 _eden_capacity_bytes_before_gc = 1199 (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc; 1200 1201 if (full) { 1202 _metaspace_used_bytes_before_gc = MetaspaceAux::allocated_used_bytes(); 1203 } 1204 } 1205 1206 void G1CollectorPolicy::print_heap_transition() { 1207 _g1->print_size_transition(gclog_or_tty, 1208 _heap_used_bytes_before_gc, 1209 _g1->used(), 1210 _g1->capacity()); 1211 } 1212 1213 void G1CollectorPolicy::print_detailed_heap_transition(bool full) { 1214 YoungList* young_list = _g1->young_list(); 1215 1216 size_t eden_used_bytes_after_gc = young_list->eden_used_bytes(); 1217 size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes(); 1218 size_t heap_used_bytes_after_gc = _g1->used(); 1219 1220 size_t heap_capacity_bytes_after_gc = _g1->capacity(); 1221 size_t eden_capacity_bytes_after_gc = 1222 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc; 1223 1224 gclog_or_tty->print( 1225 " [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") " 1226 "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" " 1227 "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->" 1228 EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]", 1229 EXT_SIZE_PARAMS(_eden_used_bytes_before_gc), 1230 EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc), 1231 EXT_SIZE_PARAMS(eden_used_bytes_after_gc), 1232 EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc), 1233 EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc), 1234 EXT_SIZE_PARAMS(survivor_used_bytes_after_gc), 1235 EXT_SIZE_PARAMS(_heap_used_bytes_before_gc), 1236 EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc), 1237 EXT_SIZE_PARAMS(heap_used_bytes_after_gc), 1238 EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc)); 1239 1240 if (full) { 1241 MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc); 1242 } 1243 1244 gclog_or_tty->cr(); 1245 } 1246 1247 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time, 1248 double update_rs_processed_buffers, 1249 double goal_ms) { 1250 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 1251 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine(); 1252 1253 if (G1UseAdaptiveConcRefinement) { 1254 const int k_gy = 3, k_gr = 6; 1255 const double inc_k = 1.1, dec_k = 0.9; 1256 1257 int g = cg1r->green_zone(); 1258 if (update_rs_time > goal_ms) { 1259 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing. 1260 } else { 1261 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) { 1262 g = (int)MAX2(g * inc_k, g + 1.0); 1263 } 1264 } 1265 // Change the refinement threads params 1266 cg1r->set_green_zone(g); 1267 cg1r->set_yellow_zone(g * k_gy); 1268 cg1r->set_red_zone(g * k_gr); 1269 cg1r->reinitialize_threads(); 1270 1271 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1); 1272 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta, 1273 cg1r->yellow_zone()); 1274 // Change the barrier params 1275 dcqs.set_process_completed_threshold(processing_threshold); 1276 dcqs.set_max_completed_queue(cg1r->red_zone()); 1277 } 1278 1279 int curr_queue_size = dcqs.completed_buffers_num(); 1280 if (curr_queue_size >= cg1r->yellow_zone()) { 1281 dcqs.set_completed_queue_padding(curr_queue_size); 1282 } else { 1283 dcqs.set_completed_queue_padding(0); 1284 } 1285 dcqs.notify_if_necessary(); 1286 } 1287 1288 double 1289 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards, 1290 size_t scanned_cards) { 1291 return 1292 predict_rs_update_time_ms(pending_cards) + 1293 predict_rs_scan_time_ms(scanned_cards) + 1294 predict_constant_other_time_ms(); 1295 } 1296 1297 double 1298 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) { 1299 size_t rs_length = predict_rs_length_diff(); 1300 size_t card_num; 1301 if (gcs_are_young()) { 1302 card_num = predict_young_card_num(rs_length); 1303 } else { 1304 card_num = predict_non_young_card_num(rs_length); 1305 } 1306 return predict_base_elapsed_time_ms(pending_cards, card_num); 1307 } 1308 1309 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) { 1310 size_t bytes_to_copy; 1311 if (hr->is_marked()) 1312 bytes_to_copy = hr->max_live_bytes(); 1313 else { 1314 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant"); 1315 int age = hr->age_in_surv_rate_group(); 1316 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group()); 1317 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate); 1318 } 1319 return bytes_to_copy; 1320 } 1321 1322 double 1323 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr, 1324 bool for_young_gc) { 1325 size_t rs_length = hr->rem_set()->occupied(); 1326 size_t card_num; 1327 1328 // Predicting the number of cards is based on which type of GC 1329 // we're predicting for. 1330 if (for_young_gc) { 1331 card_num = predict_young_card_num(rs_length); 1332 } else { 1333 card_num = predict_non_young_card_num(rs_length); 1334 } 1335 size_t bytes_to_copy = predict_bytes_to_copy(hr); 1336 1337 double region_elapsed_time_ms = 1338 predict_rs_scan_time_ms(card_num) + 1339 predict_object_copy_time_ms(bytes_to_copy); 1340 1341 // The prediction of the "other" time for this region is based 1342 // upon the region type and NOT the GC type. 1343 if (hr->is_young()) { 1344 region_elapsed_time_ms += predict_young_other_time_ms(1); 1345 } else { 1346 region_elapsed_time_ms += predict_non_young_other_time_ms(1); 1347 } 1348 return region_elapsed_time_ms; 1349 } 1350 1351 void 1352 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length, 1353 uint survivor_cset_region_length) { 1354 _eden_cset_region_length = eden_cset_region_length; 1355 _survivor_cset_region_length = survivor_cset_region_length; 1356 _old_cset_region_length = 0; 1357 } 1358 1359 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) { 1360 _recorded_rs_lengths = rs_lengths; 1361 } 1362 1363 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec, 1364 double elapsed_ms) { 1365 _recent_gc_times_ms->add(elapsed_ms); 1366 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec); 1367 _prev_collection_pause_end_ms = end_time_sec * 1000.0; 1368 } 1369 1370 size_t G1CollectorPolicy::expansion_amount() { 1371 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0; 1372 double threshold = _gc_overhead_perc; 1373 if (recent_gc_overhead > threshold) { 1374 // We will double the existing space, or take 1375 // G1ExpandByPercentOfAvailable % of the available expansion 1376 // space, whichever is smaller, bounded below by a minimum 1377 // expansion (unless that's all that's left.) 1378 const size_t min_expand_bytes = 1*M; 1379 size_t reserved_bytes = _g1->max_capacity(); 1380 size_t committed_bytes = _g1->capacity(); 1381 size_t uncommitted_bytes = reserved_bytes - committed_bytes; 1382 size_t expand_bytes; 1383 size_t expand_bytes_via_pct = 1384 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100; 1385 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes); 1386 expand_bytes = MAX2(expand_bytes, min_expand_bytes); 1387 expand_bytes = MIN2(expand_bytes, uncommitted_bytes); 1388 1389 ergo_verbose5(ErgoHeapSizing, 1390 "attempt heap expansion", 1391 ergo_format_reason("recent GC overhead higher than " 1392 "threshold after GC") 1393 ergo_format_perc("recent GC overhead") 1394 ergo_format_perc("threshold") 1395 ergo_format_byte("uncommitted") 1396 ergo_format_byte_perc("calculated expansion amount"), 1397 recent_gc_overhead, threshold, 1398 uncommitted_bytes, 1399 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable); 1400 1401 return expand_bytes; 1402 } else { 1403 return 0; 1404 } 1405 } 1406 1407 void G1CollectorPolicy::print_tracing_info() const { 1408 _trace_gen0_time_data.print(); 1409 _trace_gen1_time_data.print(); 1410 } 1411 1412 void G1CollectorPolicy::print_yg_surv_rate_info() const { 1413 #ifndef PRODUCT 1414 _short_lived_surv_rate_group->print_surv_rate_summary(); 1415 // add this call for any other surv rate groups 1416 #endif // PRODUCT 1417 } 1418 1419 uint G1CollectorPolicy::max_regions(int purpose) { 1420 switch (purpose) { 1421 case GCAllocForSurvived: 1422 return _max_survivor_regions; 1423 case GCAllocForTenured: 1424 return REGIONS_UNLIMITED; 1425 default: 1426 ShouldNotReachHere(); 1427 return REGIONS_UNLIMITED; 1428 }; 1429 } 1430 1431 void G1CollectorPolicy::update_max_gc_locker_expansion() { 1432 uint expansion_region_num = 0; 1433 if (GCLockerEdenExpansionPercent > 0) { 1434 double perc = (double) GCLockerEdenExpansionPercent / 100.0; 1435 double expansion_region_num_d = perc * (double) _young_list_target_length; 1436 // We use ceiling so that if expansion_region_num_d is > 0.0 (but 1437 // less than 1.0) we'll get 1. 1438 expansion_region_num = (uint) ceil(expansion_region_num_d); 1439 } else { 1440 assert(expansion_region_num == 0, "sanity"); 1441 } 1442 _young_list_max_length = _young_list_target_length + expansion_region_num; 1443 assert(_young_list_target_length <= _young_list_max_length, "post-condition"); 1444 } 1445 1446 // Calculates survivor space parameters. 1447 void G1CollectorPolicy::update_survivors_policy() { 1448 double max_survivor_regions_d = 1449 (double) _young_list_target_length / (double) SurvivorRatio; 1450 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but 1451 // smaller than 1.0) we'll get 1. 1452 _max_survivor_regions = (uint) ceil(max_survivor_regions_d); 1453 1454 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold( 1455 HeapRegion::GrainWords * _max_survivor_regions); 1456 } 1457 1458 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle( 1459 GCCause::Cause gc_cause) { 1460 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle(); 1461 if (!during_cycle) { 1462 ergo_verbose1(ErgoConcCycles, 1463 "request concurrent cycle initiation", 1464 ergo_format_reason("requested by GC cause") 1465 ergo_format_str("GC cause"), 1466 GCCause::to_string(gc_cause)); 1467 set_initiate_conc_mark_if_possible(); 1468 return true; 1469 } else { 1470 ergo_verbose1(ErgoConcCycles, 1471 "do not request concurrent cycle initiation", 1472 ergo_format_reason("concurrent cycle already in progress") 1473 ergo_format_str("GC cause"), 1474 GCCause::to_string(gc_cause)); 1475 return false; 1476 } 1477 } 1478 1479 void 1480 G1CollectorPolicy::decide_on_conc_mark_initiation() { 1481 // We are about to decide on whether this pause will be an 1482 // initial-mark pause. 1483 1484 // First, during_initial_mark_pause() should not be already set. We 1485 // will set it here if we have to. However, it should be cleared by 1486 // the end of the pause (it's only set for the duration of an 1487 // initial-mark pause). 1488 assert(!during_initial_mark_pause(), "pre-condition"); 1489 1490 if (initiate_conc_mark_if_possible()) { 1491 // We had noticed on a previous pause that the heap occupancy has 1492 // gone over the initiating threshold and we should start a 1493 // concurrent marking cycle. So we might initiate one. 1494 1495 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle(); 1496 if (!during_cycle) { 1497 // The concurrent marking thread is not "during a cycle", i.e., 1498 // it has completed the last one. So we can go ahead and 1499 // initiate a new cycle. 1500 1501 set_during_initial_mark_pause(); 1502 // We do not allow mixed GCs during marking. 1503 if (!gcs_are_young()) { 1504 set_gcs_are_young(true); 1505 ergo_verbose0(ErgoMixedGCs, 1506 "end mixed GCs", 1507 ergo_format_reason("concurrent cycle is about to start")); 1508 } 1509 1510 // And we can now clear initiate_conc_mark_if_possible() as 1511 // we've already acted on it. 1512 clear_initiate_conc_mark_if_possible(); 1513 1514 ergo_verbose0(ErgoConcCycles, 1515 "initiate concurrent cycle", 1516 ergo_format_reason("concurrent cycle initiation requested")); 1517 } else { 1518 // The concurrent marking thread is still finishing up the 1519 // previous cycle. If we start one right now the two cycles 1520 // overlap. In particular, the concurrent marking thread might 1521 // be in the process of clearing the next marking bitmap (which 1522 // we will use for the next cycle if we start one). Starting a 1523 // cycle now will be bad given that parts of the marking 1524 // information might get cleared by the marking thread. And we 1525 // cannot wait for the marking thread to finish the cycle as it 1526 // periodically yields while clearing the next marking bitmap 1527 // and, if it's in a yield point, it's waiting for us to 1528 // finish. So, at this point we will not start a cycle and we'll 1529 // let the concurrent marking thread complete the last one. 1530 ergo_verbose0(ErgoConcCycles, 1531 "do not initiate concurrent cycle", 1532 ergo_format_reason("concurrent cycle already in progress")); 1533 } 1534 } 1535 } 1536 1537 class KnownGarbageClosure: public HeapRegionClosure { 1538 G1CollectedHeap* _g1h; 1539 CollectionSetChooser* _hrSorted; 1540 1541 public: 1542 KnownGarbageClosure(CollectionSetChooser* hrSorted) : 1543 _g1h(G1CollectedHeap::heap()), _hrSorted(hrSorted) { } 1544 1545 bool doHeapRegion(HeapRegion* r) { 1546 // We only include humongous regions in collection 1547 // sets when concurrent mark shows that their contained object is 1548 // unreachable. 1549 1550 // Do we have any marking information for this region? 1551 if (r->is_marked()) { 1552 // We will skip any region that's currently used as an old GC 1553 // alloc region (we should not consider those for collection 1554 // before we fill them up). 1555 if (_hrSorted->should_add(r) && !_g1h->is_old_gc_alloc_region(r)) { 1556 _hrSorted->add_region(r); 1557 } 1558 } 1559 return false; 1560 } 1561 }; 1562 1563 class ParKnownGarbageHRClosure: public HeapRegionClosure { 1564 G1CollectedHeap* _g1h; 1565 CSetChooserParUpdater _cset_updater; 1566 1567 public: 1568 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted, 1569 uint chunk_size) : 1570 _g1h(G1CollectedHeap::heap()), 1571 _cset_updater(hrSorted, true /* parallel */, chunk_size) { } 1572 1573 bool doHeapRegion(HeapRegion* r) { 1574 // Do we have any marking information for this region? 1575 if (r->is_marked()) { 1576 // We will skip any region that's currently used as an old GC 1577 // alloc region (we should not consider those for collection 1578 // before we fill them up). 1579 if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) { 1580 _cset_updater.add_region(r); 1581 } 1582 } 1583 return false; 1584 } 1585 }; 1586 1587 class ParKnownGarbageTask: public AbstractGangTask { 1588 CollectionSetChooser* _hrSorted; 1589 uint _chunk_size; 1590 G1CollectedHeap* _g1; 1591 public: 1592 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size) : 1593 AbstractGangTask("ParKnownGarbageTask"), 1594 _hrSorted(hrSorted), _chunk_size(chunk_size), 1595 _g1(G1CollectedHeap::heap()) { } 1596 1597 void work(uint worker_id) { 1598 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size); 1599 1600 // Back to zero for the claim value. 1601 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, worker_id, 1602 _g1->workers()->active_workers(), 1603 HeapRegion::InitialClaimValue); 1604 } 1605 }; 1606 1607 void 1608 G1CollectorPolicy::record_concurrent_mark_cleanup_end(int no_of_gc_threads) { 1609 _collectionSetChooser->clear(); 1610 1611 uint region_num = _g1->n_regions(); 1612 if (G1CollectedHeap::use_parallel_gc_threads()) { 1613 const uint OverpartitionFactor = 4; 1614 uint WorkUnit; 1615 // The use of MinChunkSize = 8 in the original code 1616 // causes some assertion failures when the total number of 1617 // region is less than 8. The code here tries to fix that. 1618 // Should the original code also be fixed? 1619 if (no_of_gc_threads > 0) { 1620 const uint MinWorkUnit = MAX2(region_num / no_of_gc_threads, 1U); 1621 WorkUnit = MAX2(region_num / (no_of_gc_threads * OverpartitionFactor), 1622 MinWorkUnit); 1623 } else { 1624 assert(no_of_gc_threads > 0, 1625 "The active gc workers should be greater than 0"); 1626 // In a product build do something reasonable to avoid a crash. 1627 const uint MinWorkUnit = MAX2(region_num / (uint) ParallelGCThreads, 1U); 1628 WorkUnit = 1629 MAX2(region_num / (uint) (ParallelGCThreads * OverpartitionFactor), 1630 MinWorkUnit); 1631 } 1632 _collectionSetChooser->prepare_for_par_region_addition(_g1->n_regions(), 1633 WorkUnit); 1634 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser, 1635 (int) WorkUnit); 1636 _g1->workers()->run_task(&parKnownGarbageTask); 1637 1638 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue), 1639 "sanity check"); 1640 } else { 1641 KnownGarbageClosure knownGarbagecl(_collectionSetChooser); 1642 _g1->heap_region_iterate(&knownGarbagecl); 1643 } 1644 1645 _collectionSetChooser->sort_regions(); 1646 1647 double end_sec = os::elapsedTime(); 1648 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0; 1649 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms); 1650 _cur_mark_stop_world_time_ms += elapsed_time_ms; 1651 _prev_collection_pause_end_ms += elapsed_time_ms; 1652 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true); 1653 } 1654 1655 // Add the heap region at the head of the non-incremental collection set 1656 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) { 1657 assert(_inc_cset_build_state == Active, "Precondition"); 1658 assert(!hr->is_young(), "non-incremental add of young region"); 1659 1660 assert(!hr->in_collection_set(), "should not already be in the CSet"); 1661 hr->set_in_collection_set(true); 1662 hr->set_next_in_collection_set(_collection_set); 1663 _collection_set = hr; 1664 _collection_set_bytes_used_before += hr->used(); 1665 _g1->register_region_with_in_cset_fast_test(hr); 1666 size_t rs_length = hr->rem_set()->occupied(); 1667 _recorded_rs_lengths += rs_length; 1668 _old_cset_region_length += 1; 1669 } 1670 1671 // Initialize the per-collection-set information 1672 void G1CollectorPolicy::start_incremental_cset_building() { 1673 assert(_inc_cset_build_state == Inactive, "Precondition"); 1674 1675 _inc_cset_head = NULL; 1676 _inc_cset_tail = NULL; 1677 _inc_cset_bytes_used_before = 0; 1678 1679 _inc_cset_max_finger = 0; 1680 _inc_cset_recorded_rs_lengths = 0; 1681 _inc_cset_recorded_rs_lengths_diffs = 0; 1682 _inc_cset_predicted_elapsed_time_ms = 0.0; 1683 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0; 1684 _inc_cset_build_state = Active; 1685 } 1686 1687 void G1CollectorPolicy::finalize_incremental_cset_building() { 1688 assert(_inc_cset_build_state == Active, "Precondition"); 1689 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint"); 1690 1691 // The two "main" fields, _inc_cset_recorded_rs_lengths and 1692 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread 1693 // that adds a new region to the CSet. Further updates by the 1694 // concurrent refinement thread that samples the young RSet lengths 1695 // are accumulated in the *_diffs fields. Here we add the diffs to 1696 // the "main" fields. 1697 1698 if (_inc_cset_recorded_rs_lengths_diffs >= 0) { 1699 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs; 1700 } else { 1701 // This is defensive. The diff should in theory be always positive 1702 // as RSets can only grow between GCs. However, given that we 1703 // sample their size concurrently with other threads updating them 1704 // it's possible that we might get the wrong size back, which 1705 // could make the calculations somewhat inaccurate. 1706 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs); 1707 if (_inc_cset_recorded_rs_lengths >= diffs) { 1708 _inc_cset_recorded_rs_lengths -= diffs; 1709 } else { 1710 _inc_cset_recorded_rs_lengths = 0; 1711 } 1712 } 1713 _inc_cset_predicted_elapsed_time_ms += 1714 _inc_cset_predicted_elapsed_time_ms_diffs; 1715 1716 _inc_cset_recorded_rs_lengths_diffs = 0; 1717 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0; 1718 } 1719 1720 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) { 1721 // This routine is used when: 1722 // * adding survivor regions to the incremental cset at the end of an 1723 // evacuation pause, 1724 // * adding the current allocation region to the incremental cset 1725 // when it is retired, and 1726 // * updating existing policy information for a region in the 1727 // incremental cset via young list RSet sampling. 1728 // Therefore this routine may be called at a safepoint by the 1729 // VM thread, or in-between safepoints by mutator threads (when 1730 // retiring the current allocation region) or a concurrent 1731 // refine thread (RSet sampling). 1732 1733 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young()); 1734 size_t used_bytes = hr->used(); 1735 _inc_cset_recorded_rs_lengths += rs_length; 1736 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms; 1737 _inc_cset_bytes_used_before += used_bytes; 1738 1739 // Cache the values we have added to the aggregated informtion 1740 // in the heap region in case we have to remove this region from 1741 // the incremental collection set, or it is updated by the 1742 // rset sampling code 1743 hr->set_recorded_rs_length(rs_length); 1744 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms); 1745 } 1746 1747 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr, 1748 size_t new_rs_length) { 1749 // Update the CSet information that is dependent on the new RS length 1750 assert(hr->is_young(), "Precondition"); 1751 assert(!SafepointSynchronize::is_at_safepoint(), 1752 "should not be at a safepoint"); 1753 1754 // We could have updated _inc_cset_recorded_rs_lengths and 1755 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do 1756 // that atomically, as this code is executed by a concurrent 1757 // refinement thread, potentially concurrently with a mutator thread 1758 // allocating a new region and also updating the same fields. To 1759 // avoid the atomic operations we accumulate these updates on two 1760 // separate fields (*_diffs) and we'll just add them to the "main" 1761 // fields at the start of a GC. 1762 1763 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length(); 1764 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length; 1765 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff; 1766 1767 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms(); 1768 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young()); 1769 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms; 1770 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff; 1771 1772 hr->set_recorded_rs_length(new_rs_length); 1773 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms); 1774 } 1775 1776 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) { 1777 assert(hr->is_young(), "invariant"); 1778 assert(hr->young_index_in_cset() > -1, "should have already been set"); 1779 assert(_inc_cset_build_state == Active, "Precondition"); 1780 1781 // We need to clear and set the cached recorded/cached collection set 1782 // information in the heap region here (before the region gets added 1783 // to the collection set). An individual heap region's cached values 1784 // are calculated, aggregated with the policy collection set info, 1785 // and cached in the heap region here (initially) and (subsequently) 1786 // by the Young List sampling code. 1787 1788 size_t rs_length = hr->rem_set()->occupied(); 1789 add_to_incremental_cset_info(hr, rs_length); 1790 1791 HeapWord* hr_end = hr->end(); 1792 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end); 1793 1794 assert(!hr->in_collection_set(), "invariant"); 1795 hr->set_in_collection_set(true); 1796 assert( hr->next_in_collection_set() == NULL, "invariant"); 1797 1798 _g1->register_region_with_in_cset_fast_test(hr); 1799 } 1800 1801 // Add the region at the RHS of the incremental cset 1802 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) { 1803 // We should only ever be appending survivors at the end of a pause 1804 assert( hr->is_survivor(), "Logic"); 1805 1806 // Do the 'common' stuff 1807 add_region_to_incremental_cset_common(hr); 1808 1809 // Now add the region at the right hand side 1810 if (_inc_cset_tail == NULL) { 1811 assert(_inc_cset_head == NULL, "invariant"); 1812 _inc_cset_head = hr; 1813 } else { 1814 _inc_cset_tail->set_next_in_collection_set(hr); 1815 } 1816 _inc_cset_tail = hr; 1817 } 1818 1819 // Add the region to the LHS of the incremental cset 1820 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) { 1821 // Survivors should be added to the RHS at the end of a pause 1822 assert(!hr->is_survivor(), "Logic"); 1823 1824 // Do the 'common' stuff 1825 add_region_to_incremental_cset_common(hr); 1826 1827 // Add the region at the left hand side 1828 hr->set_next_in_collection_set(_inc_cset_head); 1829 if (_inc_cset_head == NULL) { 1830 assert(_inc_cset_tail == NULL, "Invariant"); 1831 _inc_cset_tail = hr; 1832 } 1833 _inc_cset_head = hr; 1834 } 1835 1836 #ifndef PRODUCT 1837 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) { 1838 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be"); 1839 1840 st->print_cr("\nCollection_set:"); 1841 HeapRegion* csr = list_head; 1842 while (csr != NULL) { 1843 HeapRegion* next = csr->next_in_collection_set(); 1844 assert(csr->in_collection_set(), "bad CS"); 1845 st->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d", 1846 HR_FORMAT_PARAMS(csr), 1847 csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(), 1848 csr->age_in_surv_rate_group_cond()); 1849 csr = next; 1850 } 1851 } 1852 #endif // !PRODUCT 1853 1854 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) { 1855 // Returns the given amount of reclaimable bytes (that represents 1856 // the amount of reclaimable space still to be collected) as a 1857 // percentage of the current heap capacity. 1858 size_t capacity_bytes = _g1->capacity(); 1859 return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes; 1860 } 1861 1862 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str, 1863 const char* false_action_str) { 1864 CollectionSetChooser* cset_chooser = _collectionSetChooser; 1865 if (cset_chooser->is_empty()) { 1866 ergo_verbose0(ErgoMixedGCs, 1867 false_action_str, 1868 ergo_format_reason("candidate old regions not available")); 1869 return false; 1870 } 1871 1872 // Is the amount of uncollected reclaimable space above G1HeapWastePercent? 1873 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes(); 1874 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes); 1875 double threshold = (double) G1HeapWastePercent; 1876 if (reclaimable_perc <= threshold) { 1877 ergo_verbose4(ErgoMixedGCs, 1878 false_action_str, 1879 ergo_format_reason("reclaimable percentage not over threshold") 1880 ergo_format_region("candidate old regions") 1881 ergo_format_byte_perc("reclaimable") 1882 ergo_format_perc("threshold"), 1883 cset_chooser->remaining_regions(), 1884 reclaimable_bytes, 1885 reclaimable_perc, threshold); 1886 return false; 1887 } 1888 1889 ergo_verbose4(ErgoMixedGCs, 1890 true_action_str, 1891 ergo_format_reason("candidate old regions available") 1892 ergo_format_region("candidate old regions") 1893 ergo_format_byte_perc("reclaimable") 1894 ergo_format_perc("threshold"), 1895 cset_chooser->remaining_regions(), 1896 reclaimable_bytes, 1897 reclaimable_perc, threshold); 1898 return true; 1899 } 1900 1901 uint G1CollectorPolicy::calc_min_old_cset_length() { 1902 // The min old CSet region bound is based on the maximum desired 1903 // number of mixed GCs after a cycle. I.e., even if some old regions 1904 // look expensive, we should add them to the CSet anyway to make 1905 // sure we go through the available old regions in no more than the 1906 // maximum desired number of mixed GCs. 1907 // 1908 // The calculation is based on the number of marked regions we added 1909 // to the CSet chooser in the first place, not how many remain, so 1910 // that the result is the same during all mixed GCs that follow a cycle. 1911 1912 const size_t region_num = (size_t) _collectionSetChooser->length(); 1913 const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1); 1914 size_t result = region_num / gc_num; 1915 // emulate ceiling 1916 if (result * gc_num < region_num) { 1917 result += 1; 1918 } 1919 return (uint) result; 1920 } 1921 1922 uint G1CollectorPolicy::calc_max_old_cset_length() { 1923 // The max old CSet region bound is based on the threshold expressed 1924 // as a percentage of the heap size. I.e., it should bound the 1925 // number of old regions added to the CSet irrespective of how many 1926 // of them are available. 1927 1928 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 1929 const size_t region_num = g1h->n_regions(); 1930 const size_t perc = (size_t) G1OldCSetRegionThresholdPercent; 1931 size_t result = region_num * perc / 100; 1932 // emulate ceiling 1933 if (100 * result < region_num * perc) { 1934 result += 1; 1935 } 1936 return (uint) result; 1937 } 1938 1939 1940 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info) { 1941 double young_start_time_sec = os::elapsedTime(); 1942 1943 YoungList* young_list = _g1->young_list(); 1944 finalize_incremental_cset_building(); 1945 1946 guarantee(target_pause_time_ms > 0.0, 1947 err_msg("target_pause_time_ms = %1.6lf should be positive", 1948 target_pause_time_ms)); 1949 guarantee(_collection_set == NULL, "Precondition"); 1950 1951 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards); 1952 double predicted_pause_time_ms = base_time_ms; 1953 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0); 1954 1955 ergo_verbose4(ErgoCSetConstruction | ErgoHigh, 1956 "start choosing CSet", 1957 ergo_format_size("_pending_cards") 1958 ergo_format_ms("predicted base time") 1959 ergo_format_ms("remaining time") 1960 ergo_format_ms("target pause time"), 1961 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms); 1962 1963 _last_gc_was_young = gcs_are_young() ? true : false; 1964 1965 if (_last_gc_was_young) { 1966 _trace_gen0_time_data.increment_young_collection_count(); 1967 } else { 1968 _trace_gen0_time_data.increment_mixed_collection_count(); 1969 } 1970 1971 // The young list is laid with the survivor regions from the previous 1972 // pause are appended to the RHS of the young list, i.e. 1973 // [Newly Young Regions ++ Survivors from last pause]. 1974 1975 uint survivor_region_length = young_list->survivor_length(); 1976 uint eden_region_length = young_list->length() - survivor_region_length; 1977 init_cset_region_lengths(eden_region_length, survivor_region_length); 1978 1979 HeapRegion* hr = young_list->first_survivor_region(); 1980 while (hr != NULL) { 1981 assert(hr->is_survivor(), "badly formed young list"); 1982 hr->set_young(); 1983 hr = hr->get_next_young_region(); 1984 } 1985 1986 // Clear the fields that point to the survivor list - they are all young now. 1987 young_list->clear_survivors(); 1988 1989 _collection_set = _inc_cset_head; 1990 _collection_set_bytes_used_before = _inc_cset_bytes_used_before; 1991 time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0); 1992 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms; 1993 1994 ergo_verbose3(ErgoCSetConstruction | ErgoHigh, 1995 "add young regions to CSet", 1996 ergo_format_region("eden") 1997 ergo_format_region("survivors") 1998 ergo_format_ms("predicted young region time"), 1999 eden_region_length, survivor_region_length, 2000 _inc_cset_predicted_elapsed_time_ms); 2001 2002 // The number of recorded young regions is the incremental 2003 // collection set's current size 2004 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths); 2005 2006 double young_end_time_sec = os::elapsedTime(); 2007 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0); 2008 2009 // Set the start of the non-young choice time. 2010 double non_young_start_time_sec = young_end_time_sec; 2011 2012 if (!gcs_are_young()) { 2013 CollectionSetChooser* cset_chooser = _collectionSetChooser; 2014 cset_chooser->verify(); 2015 const uint min_old_cset_length = calc_min_old_cset_length(); 2016 const uint max_old_cset_length = calc_max_old_cset_length(); 2017 2018 uint expensive_region_num = 0; 2019 bool check_time_remaining = adaptive_young_list_length(); 2020 2021 HeapRegion* hr = cset_chooser->peek(); 2022 while (hr != NULL) { 2023 if (old_cset_region_length() >= max_old_cset_length) { 2024 // Added maximum number of old regions to the CSet. 2025 ergo_verbose2(ErgoCSetConstruction, 2026 "finish adding old regions to CSet", 2027 ergo_format_reason("old CSet region num reached max") 2028 ergo_format_region("old") 2029 ergo_format_region("max"), 2030 old_cset_region_length(), max_old_cset_length); 2031 break; 2032 } 2033 2034 2035 // Stop adding regions if the remaining reclaimable space is 2036 // not above G1HeapWastePercent. 2037 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes(); 2038 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes); 2039 double threshold = (double) G1HeapWastePercent; 2040 if (reclaimable_perc <= threshold) { 2041 // We've added enough old regions that the amount of uncollected 2042 // reclaimable space is at or below the waste threshold. Stop 2043 // adding old regions to the CSet. 2044 ergo_verbose5(ErgoCSetConstruction, 2045 "finish adding old regions to CSet", 2046 ergo_format_reason("reclaimable percentage not over threshold") 2047 ergo_format_region("old") 2048 ergo_format_region("max") 2049 ergo_format_byte_perc("reclaimable") 2050 ergo_format_perc("threshold"), 2051 old_cset_region_length(), 2052 max_old_cset_length, 2053 reclaimable_bytes, 2054 reclaimable_perc, threshold); 2055 break; 2056 } 2057 2058 double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young()); 2059 if (check_time_remaining) { 2060 if (predicted_time_ms > time_remaining_ms) { 2061 // Too expensive for the current CSet. 2062 2063 if (old_cset_region_length() >= min_old_cset_length) { 2064 // We have added the minimum number of old regions to the CSet, 2065 // we are done with this CSet. 2066 ergo_verbose4(ErgoCSetConstruction, 2067 "finish adding old regions to CSet", 2068 ergo_format_reason("predicted time is too high") 2069 ergo_format_ms("predicted time") 2070 ergo_format_ms("remaining time") 2071 ergo_format_region("old") 2072 ergo_format_region("min"), 2073 predicted_time_ms, time_remaining_ms, 2074 old_cset_region_length(), min_old_cset_length); 2075 break; 2076 } 2077 2078 // We'll add it anyway given that we haven't reached the 2079 // minimum number of old regions. 2080 expensive_region_num += 1; 2081 } 2082 } else { 2083 if (old_cset_region_length() >= min_old_cset_length) { 2084 // In the non-auto-tuning case, we'll finish adding regions 2085 // to the CSet if we reach the minimum. 2086 ergo_verbose2(ErgoCSetConstruction, 2087 "finish adding old regions to CSet", 2088 ergo_format_reason("old CSet region num reached min") 2089 ergo_format_region("old") 2090 ergo_format_region("min"), 2091 old_cset_region_length(), min_old_cset_length); 2092 break; 2093 } 2094 } 2095 2096 // We will add this region to the CSet. 2097 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0); 2098 predicted_pause_time_ms += predicted_time_ms; 2099 cset_chooser->remove_and_move_to_next(hr); 2100 _g1->old_set_remove(hr); 2101 add_old_region_to_cset(hr); 2102 2103 hr = cset_chooser->peek(); 2104 } 2105 if (hr == NULL) { 2106 ergo_verbose0(ErgoCSetConstruction, 2107 "finish adding old regions to CSet", 2108 ergo_format_reason("candidate old regions not available")); 2109 } 2110 2111 if (expensive_region_num > 0) { 2112 // We print the information once here at the end, predicated on 2113 // whether we added any apparently expensive regions or not, to 2114 // avoid generating output per region. 2115 ergo_verbose4(ErgoCSetConstruction, 2116 "added expensive regions to CSet", 2117 ergo_format_reason("old CSet region num not reached min") 2118 ergo_format_region("old") 2119 ergo_format_region("expensive") 2120 ergo_format_region("min") 2121 ergo_format_ms("remaining time"), 2122 old_cset_region_length(), 2123 expensive_region_num, 2124 min_old_cset_length, 2125 time_remaining_ms); 2126 } 2127 2128 cset_chooser->verify(); 2129 } 2130 2131 stop_incremental_cset_building(); 2132 2133 ergo_verbose5(ErgoCSetConstruction, 2134 "finish choosing CSet", 2135 ergo_format_region("eden") 2136 ergo_format_region("survivors") 2137 ergo_format_region("old") 2138 ergo_format_ms("predicted pause time") 2139 ergo_format_ms("target pause time"), 2140 eden_region_length, survivor_region_length, 2141 old_cset_region_length(), 2142 predicted_pause_time_ms, target_pause_time_ms); 2143 2144 double non_young_end_time_sec = os::elapsedTime(); 2145 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0); 2146 evacuation_info.set_collectionset_regions(cset_region_length()); 2147 } 2148 2149 void TraceGen0TimeData::record_start_collection(double time_to_stop_the_world_ms) { 2150 if(TraceGen0Time) { 2151 _all_stop_world_times_ms.add(time_to_stop_the_world_ms); 2152 } 2153 } 2154 2155 void TraceGen0TimeData::record_yield_time(double yield_time_ms) { 2156 if(TraceGen0Time) { 2157 _all_yield_times_ms.add(yield_time_ms); 2158 } 2159 } 2160 2161 void TraceGen0TimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) { 2162 if(TraceGen0Time) { 2163 _total.add(pause_time_ms); 2164 _other.add(pause_time_ms - phase_times->accounted_time_ms()); 2165 _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms()); 2166 _parallel.add(phase_times->cur_collection_par_time_ms()); 2167 _ext_root_scan.add(phase_times->average_last_ext_root_scan_time()); 2168 _satb_filtering.add(phase_times->average_last_satb_filtering_times_ms()); 2169 _update_rs.add(phase_times->average_last_update_rs_time()); 2170 _scan_rs.add(phase_times->average_last_scan_rs_time()); 2171 _obj_copy.add(phase_times->average_last_obj_copy_time()); 2172 _termination.add(phase_times->average_last_termination_time()); 2173 2174 double parallel_known_time = phase_times->average_last_ext_root_scan_time() + 2175 phase_times->average_last_satb_filtering_times_ms() + 2176 phase_times->average_last_update_rs_time() + 2177 phase_times->average_last_scan_rs_time() + 2178 phase_times->average_last_obj_copy_time() + 2179 + phase_times->average_last_termination_time(); 2180 2181 double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time; 2182 _parallel_other.add(parallel_other_time); 2183 _clear_ct.add(phase_times->cur_clear_ct_time_ms()); 2184 } 2185 } 2186 2187 void TraceGen0TimeData::increment_young_collection_count() { 2188 if(TraceGen0Time) { 2189 ++_young_pause_num; 2190 } 2191 } 2192 2193 void TraceGen0TimeData::increment_mixed_collection_count() { 2194 if(TraceGen0Time) { 2195 ++_mixed_pause_num; 2196 } 2197 } 2198 2199 void TraceGen0TimeData::print_summary(const char* str, 2200 const NumberSeq* seq) const { 2201 double sum = seq->sum(); 2202 gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)", 2203 str, sum / 1000.0, seq->avg()); 2204 } 2205 2206 void TraceGen0TimeData::print_summary_sd(const char* str, 2207 const NumberSeq* seq) const { 2208 print_summary(str, seq); 2209 gclog_or_tty->print_cr("%+45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)", 2210 "(num", seq->num(), seq->sd(), seq->maximum()); 2211 } 2212 2213 void TraceGen0TimeData::print() const { 2214 if (!TraceGen0Time) { 2215 return; 2216 } 2217 2218 gclog_or_tty->print_cr("ALL PAUSES"); 2219 print_summary_sd(" Total", &_total); 2220 gclog_or_tty->print_cr(""); 2221 gclog_or_tty->print_cr(""); 2222 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num); 2223 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num); 2224 gclog_or_tty->print_cr(""); 2225 2226 gclog_or_tty->print_cr("EVACUATION PAUSES"); 2227 2228 if (_young_pause_num == 0 && _mixed_pause_num == 0) { 2229 gclog_or_tty->print_cr("none"); 2230 } else { 2231 print_summary_sd(" Evacuation Pauses", &_total); 2232 print_summary(" Root Region Scan Wait", &_root_region_scan_wait); 2233 print_summary(" Parallel Time", &_parallel); 2234 print_summary(" Ext Root Scanning", &_ext_root_scan); 2235 print_summary(" SATB Filtering", &_satb_filtering); 2236 print_summary(" Update RS", &_update_rs); 2237 print_summary(" Scan RS", &_scan_rs); 2238 print_summary(" Object Copy", &_obj_copy); 2239 print_summary(" Termination", &_termination); 2240 print_summary(" Parallel Other", &_parallel_other); 2241 print_summary(" Clear CT", &_clear_ct); 2242 print_summary(" Other", &_other); 2243 } 2244 gclog_or_tty->print_cr(""); 2245 2246 gclog_or_tty->print_cr("MISC"); 2247 print_summary_sd(" Stop World", &_all_stop_world_times_ms); 2248 print_summary_sd(" Yields", &_all_yield_times_ms); 2249 } 2250 2251 void TraceGen1TimeData::record_full_collection(double full_gc_time_ms) { 2252 if (TraceGen1Time) { 2253 _all_full_gc_times.add(full_gc_time_ms); 2254 } 2255 } 2256 2257 void TraceGen1TimeData::print() const { 2258 if (!TraceGen1Time) { 2259 return; 2260 } 2261 2262 if (_all_full_gc_times.num() > 0) { 2263 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s", 2264 _all_full_gc_times.num(), 2265 _all_full_gc_times.sum() / 1000.0); 2266 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg()); 2267 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]", 2268 _all_full_gc_times.sd(), 2269 _all_full_gc_times.maximum()); 2270 } 2271 }