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