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