1 /* 2 * Copyright (c) 2004, 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/shared/adaptiveSizePolicy.hpp" 27 #include "gc_interface/gcCause.hpp" 28 #include "memory/collectorPolicy.hpp" 29 #include "runtime/timer.hpp" 30 #include "utilities/ostream.hpp" 31 #include "utilities/workgroup.hpp" 32 elapsedTimer AdaptiveSizePolicy::_minor_timer; 33 elapsedTimer AdaptiveSizePolicy::_major_timer; 34 bool AdaptiveSizePolicy::_debug_perturbation = false; 35 36 // The throughput goal is implemented as 37 // _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio)) 38 // gc_cost_ratio is the ratio 39 // application cost / gc cost 40 // For example a gc_cost_ratio of 4 translates into a 41 // throughput goal of .80 42 43 AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size, 44 size_t init_promo_size, 45 size_t init_survivor_size, 46 double gc_pause_goal_sec, 47 uint gc_cost_ratio) : 48 _eden_size(init_eden_size), 49 _promo_size(init_promo_size), 50 _survivor_size(init_survivor_size), 51 _gc_pause_goal_sec(gc_pause_goal_sec), 52 _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))), 53 _gc_overhead_limit_exceeded(false), 54 _print_gc_overhead_limit_would_be_exceeded(false), 55 _gc_overhead_limit_count(0), 56 _latest_minor_mutator_interval_seconds(0), 57 _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0), 58 _young_gen_change_for_minor_throughput(0), 59 _old_gen_change_for_major_throughput(0) { 60 assert(AdaptiveSizePolicyGCTimeLimitThreshold > 0, 61 "No opportunity to clear SoftReferences before GC overhead limit"); 62 _avg_minor_pause = 63 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding); 64 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight); 65 _avg_minor_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight); 66 _avg_major_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight); 67 68 _avg_young_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); 69 _avg_old_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); 70 _avg_eden_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); 71 72 _avg_survived = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight, 73 SurvivorPadding); 74 _avg_pretenured = new AdaptivePaddedNoZeroDevAverage( 75 AdaptiveSizePolicyWeight, 76 SurvivorPadding); 77 78 _minor_pause_old_estimator = 79 new LinearLeastSquareFit(AdaptiveSizePolicyWeight); 80 _minor_pause_young_estimator = 81 new LinearLeastSquareFit(AdaptiveSizePolicyWeight); 82 _minor_collection_estimator = 83 new LinearLeastSquareFit(AdaptiveSizePolicyWeight); 84 _major_collection_estimator = 85 new LinearLeastSquareFit(AdaptiveSizePolicyWeight); 86 87 // Start the timers 88 _minor_timer.start(); 89 90 _young_gen_policy_is_ready = false; 91 } 92 93 // If the number of GC threads was set on the command line, 94 // use it. 95 // Else 96 // Calculate the number of GC threads based on the number of Java threads. 97 // Calculate the number of GC threads based on the size of the heap. 98 // Use the larger. 99 100 int AdaptiveSizePolicy::calc_default_active_workers(uintx total_workers, 101 const uintx min_workers, 102 uintx active_workers, 103 uintx application_workers) { 104 // If the user has specifically set the number of 105 // GC threads, use them. 106 107 // If the user has turned off using a dynamic number of GC threads 108 // or the users has requested a specific number, set the active 109 // number of workers to all the workers. 110 111 uintx new_active_workers = total_workers; 112 uintx prev_active_workers = active_workers; 113 uintx active_workers_by_JT = 0; 114 uintx active_workers_by_heap_size = 0; 115 116 // Always use at least min_workers but use up to 117 // GCThreadsPerJavaThreads * application threads. 118 active_workers_by_JT = 119 MAX2((uintx) GCWorkersPerJavaThread * application_workers, 120 min_workers); 121 122 // Choose a number of GC threads based on the current size 123 // of the heap. This may be complicated because the size of 124 // the heap depends on factors such as the thoughput goal. 125 // Still a large heap should be collected by more GC threads. 126 active_workers_by_heap_size = 127 MAX2((size_t) 2U, Universe::heap()->capacity() / HeapSizePerGCThread); 128 129 uintx max_active_workers = 130 MAX2(active_workers_by_JT, active_workers_by_heap_size); 131 132 // Limit the number of workers to the the number created, 133 // (workers()). 134 new_active_workers = MIN2(max_active_workers, 135 (uintx) total_workers); 136 137 // Increase GC workers instantly but decrease them more 138 // slowly. 139 if (new_active_workers < prev_active_workers) { 140 new_active_workers = 141 MAX2(min_workers, (prev_active_workers + new_active_workers) / 2); 142 } 143 144 // Check once more that the number of workers is within the limits. 145 assert(min_workers <= total_workers, "Minimum workers not consistent with total workers"); 146 assert(new_active_workers >= min_workers, "Minimum workers not observed"); 147 assert(new_active_workers <= total_workers, "Total workers not observed"); 148 149 if (ForceDynamicNumberOfGCThreads) { 150 // Assume this is debugging and jiggle the number of GC threads. 151 if (new_active_workers == prev_active_workers) { 152 if (new_active_workers < total_workers) { 153 new_active_workers++; 154 } else if (new_active_workers > min_workers) { 155 new_active_workers--; 156 } 157 } 158 if (new_active_workers == total_workers) { 159 if (_debug_perturbation) { 160 new_active_workers = min_workers; 161 } 162 _debug_perturbation = !_debug_perturbation; 163 } 164 assert((new_active_workers <= (uintx) ParallelGCThreads) && 165 (new_active_workers >= min_workers), 166 "Jiggled active workers too much"); 167 } 168 169 if (TraceDynamicGCThreads) { 170 gclog_or_tty->print_cr("GCTaskManager::calc_default_active_workers() : " 171 "active_workers(): %d new_acitve_workers: %d " 172 "prev_active_workers: %d\n" 173 " active_workers_by_JT: %d active_workers_by_heap_size: %d", 174 active_workers, new_active_workers, prev_active_workers, 175 active_workers_by_JT, active_workers_by_heap_size); 176 } 177 assert(new_active_workers > 0, "Always need at least 1"); 178 return new_active_workers; 179 } 180 181 int AdaptiveSizePolicy::calc_active_workers(uintx total_workers, 182 uintx active_workers, 183 uintx application_workers) { 184 // If the user has specifically set the number of 185 // GC threads, use them. 186 187 // If the user has turned off using a dynamic number of GC threads 188 // or the users has requested a specific number, set the active 189 // number of workers to all the workers. 190 191 int new_active_workers; 192 if (!UseDynamicNumberOfGCThreads || 193 (!FLAG_IS_DEFAULT(ParallelGCThreads) && !ForceDynamicNumberOfGCThreads)) { 194 new_active_workers = total_workers; 195 } else { 196 new_active_workers = calc_default_active_workers(total_workers, 197 2, /* Minimum number of workers */ 198 active_workers, 199 application_workers); 200 } 201 assert(new_active_workers > 0, "Always need at least 1"); 202 return new_active_workers; 203 } 204 205 int AdaptiveSizePolicy::calc_active_conc_workers(uintx total_workers, 206 uintx active_workers, 207 uintx application_workers) { 208 if (!UseDynamicNumberOfGCThreads || 209 (!FLAG_IS_DEFAULT(ConcGCThreads) && !ForceDynamicNumberOfGCThreads)) { 210 return ConcGCThreads; 211 } else { 212 int no_of_gc_threads = calc_default_active_workers( 213 total_workers, 214 1, /* Minimum number of workers */ 215 active_workers, 216 application_workers); 217 return no_of_gc_threads; 218 } 219 } 220 221 bool AdaptiveSizePolicy::tenuring_threshold_change() const { 222 return decrement_tenuring_threshold_for_gc_cost() || 223 increment_tenuring_threshold_for_gc_cost() || 224 decrement_tenuring_threshold_for_survivor_limit(); 225 } 226 227 void AdaptiveSizePolicy::minor_collection_begin() { 228 // Update the interval time 229 _minor_timer.stop(); 230 // Save most recent collection time 231 _latest_minor_mutator_interval_seconds = _minor_timer.seconds(); 232 _minor_timer.reset(); 233 _minor_timer.start(); 234 } 235 236 void AdaptiveSizePolicy::update_minor_pause_young_estimator( 237 double minor_pause_in_ms) { 238 double eden_size_in_mbytes = ((double)_eden_size)/((double)M); 239 _minor_pause_young_estimator->update(eden_size_in_mbytes, 240 minor_pause_in_ms); 241 } 242 243 void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) { 244 // Update the pause time. 245 _minor_timer.stop(); 246 247 if (gc_cause != GCCause::_java_lang_system_gc || 248 UseAdaptiveSizePolicyWithSystemGC) { 249 double minor_pause_in_seconds = _minor_timer.seconds(); 250 double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS; 251 252 // Sample for performance counter 253 _avg_minor_pause->sample(minor_pause_in_seconds); 254 255 // Cost of collection (unit-less) 256 double collection_cost = 0.0; 257 if ((_latest_minor_mutator_interval_seconds > 0.0) && 258 (minor_pause_in_seconds > 0.0)) { 259 double interval_in_seconds = 260 _latest_minor_mutator_interval_seconds + minor_pause_in_seconds; 261 collection_cost = 262 minor_pause_in_seconds / interval_in_seconds; 263 _avg_minor_gc_cost->sample(collection_cost); 264 // Sample for performance counter 265 _avg_minor_interval->sample(interval_in_seconds); 266 } 267 268 // The policy does not have enough data until at least some 269 // minor collections have been done. 270 _young_gen_policy_is_ready = 271 (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold); 272 273 // Calculate variables used to estimate pause time vs. gen sizes 274 double eden_size_in_mbytes = ((double)_eden_size)/((double)M); 275 update_minor_pause_young_estimator(minor_pause_in_ms); 276 update_minor_pause_old_estimator(minor_pause_in_ms); 277 278 if (PrintAdaptiveSizePolicy && Verbose) { 279 gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: " 280 "minor gc cost: %f average: %f", collection_cost, 281 _avg_minor_gc_cost->average()); 282 gclog_or_tty->print_cr(" minor pause: %f minor period %f", 283 minor_pause_in_ms, 284 _latest_minor_mutator_interval_seconds * MILLIUNITS); 285 } 286 287 // Calculate variable used to estimate collection cost vs. gen sizes 288 assert(collection_cost >= 0.0, "Expected to be non-negative"); 289 _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost); 290 } 291 292 // Interval times use this timer to measure the mutator time. 293 // Reset the timer after the GC pause. 294 _minor_timer.reset(); 295 _minor_timer.start(); 296 } 297 298 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden, 299 uint percent_change) { 300 size_t eden_heap_delta; 301 eden_heap_delta = cur_eden / 100 * percent_change; 302 return eden_heap_delta; 303 } 304 305 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) { 306 return eden_increment(cur_eden, YoungGenerationSizeIncrement); 307 } 308 309 size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) { 310 size_t eden_heap_delta = eden_increment(cur_eden) / 311 AdaptiveSizeDecrementScaleFactor; 312 return eden_heap_delta; 313 } 314 315 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo, 316 uint percent_change) { 317 size_t promo_heap_delta; 318 promo_heap_delta = cur_promo / 100 * percent_change; 319 return promo_heap_delta; 320 } 321 322 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) { 323 return promo_increment(cur_promo, TenuredGenerationSizeIncrement); 324 } 325 326 size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) { 327 size_t promo_heap_delta = promo_increment(cur_promo); 328 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor; 329 return promo_heap_delta; 330 } 331 332 double AdaptiveSizePolicy::time_since_major_gc() const { 333 _major_timer.stop(); 334 double result = _major_timer.seconds(); 335 _major_timer.start(); 336 return result; 337 } 338 339 // Linear decay of major gc cost 340 double AdaptiveSizePolicy::decaying_major_gc_cost() const { 341 double major_interval = major_gc_interval_average_for_decay(); 342 double major_gc_cost_average = major_gc_cost(); 343 double decayed_major_gc_cost = major_gc_cost_average; 344 if(time_since_major_gc() > 0.0) { 345 decayed_major_gc_cost = major_gc_cost() * 346 (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval) 347 / time_since_major_gc(); 348 } 349 350 // The decayed cost should always be smaller than the 351 // average cost but the vagaries of finite arithmetic could 352 // produce a larger value in decayed_major_gc_cost so protect 353 // against that. 354 return MIN2(major_gc_cost_average, decayed_major_gc_cost); 355 } 356 357 // Use a value of the major gc cost that has been decayed 358 // by the factor 359 // 360 // average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale / 361 // time-since-last-major-gc 362 // 363 // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale 364 // is less than time-since-last-major-gc. 365 // 366 // In cases where there are initial major gc's that 367 // are of a relatively high cost but no later major 368 // gc's, the total gc cost can remain high because 369 // the major gc cost remains unchanged (since there are no major 370 // gc's). In such a situation the value of the unchanging 371 // major gc cost can keep the mutator throughput below 372 // the goal when in fact the major gc cost is becoming diminishingly 373 // small. Use the decaying gc cost only to decide whether to 374 // adjust for throughput. Using it also to determine the adjustment 375 // to be made for throughput also seems reasonable but there is 376 // no test case to use to decide if it is the right thing to do 377 // don't do it yet. 378 379 double AdaptiveSizePolicy::decaying_gc_cost() const { 380 double decayed_major_gc_cost = major_gc_cost(); 381 double avg_major_interval = major_gc_interval_average_for_decay(); 382 if (UseAdaptiveSizeDecayMajorGCCost && 383 (AdaptiveSizeMajorGCDecayTimeScale > 0) && 384 (avg_major_interval > 0.00)) { 385 double time_since_last_major_gc = time_since_major_gc(); 386 387 // Decay the major gc cost? 388 if (time_since_last_major_gc > 389 ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) { 390 391 // Decay using the time-since-last-major-gc 392 decayed_major_gc_cost = decaying_major_gc_cost(); 393 if (PrintGCDetails && Verbose) { 394 gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:" 395 " %f time since last major gc: %f", 396 avg_major_interval, time_since_last_major_gc); 397 gclog_or_tty->print_cr(" major gc cost: %f decayed major gc cost: %f", 398 major_gc_cost(), decayed_major_gc_cost); 399 } 400 } 401 } 402 double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost()); 403 return result; 404 } 405 406 407 void AdaptiveSizePolicy::clear_generation_free_space_flags() { 408 set_change_young_gen_for_min_pauses(0); 409 set_change_old_gen_for_maj_pauses(0); 410 411 set_change_old_gen_for_throughput(0); 412 set_change_young_gen_for_throughput(0); 413 set_decrease_for_footprint(0); 414 set_decide_at_full_gc(0); 415 } 416 417 void AdaptiveSizePolicy::check_gc_overhead_limit( 418 size_t young_live, 419 size_t eden_live, 420 size_t max_old_gen_size, 421 size_t max_eden_size, 422 bool is_full_gc, 423 GCCause::Cause gc_cause, 424 CollectorPolicy* collector_policy) { 425 426 // Ignore explicit GC's. Exiting here does not set the flag and 427 // does not reset the count. Updating of the averages for system 428 // GC's is still controlled by UseAdaptiveSizePolicyWithSystemGC. 429 if (GCCause::is_user_requested_gc(gc_cause) || 430 GCCause::is_serviceability_requested_gc(gc_cause)) { 431 return; 432 } 433 // eden_limit is the upper limit on the size of eden based on 434 // the maximum size of the young generation and the sizes 435 // of the survivor space. 436 // The question being asked is whether the gc costs are high 437 // and the space being recovered by a collection is low. 438 // free_in_young_gen is the free space in the young generation 439 // after a collection and promo_live is the free space in the old 440 // generation after a collection. 441 // 442 // Use the minimum of the current value of the live in the 443 // young gen or the average of the live in the young gen. 444 // If the current value drops quickly, that should be taken 445 // into account (i.e., don't trigger if the amount of free 446 // space has suddenly jumped up). If the current is much 447 // higher than the average, use the average since it represents 448 // the longer term behavior. 449 const size_t live_in_eden = 450 MIN2(eden_live, (size_t) avg_eden_live()->average()); 451 const size_t free_in_eden = max_eden_size > live_in_eden ? 452 max_eden_size - live_in_eden : 0; 453 const size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average()); 454 const size_t total_free_limit = free_in_old_gen + free_in_eden; 455 const size_t total_mem = max_old_gen_size + max_eden_size; 456 const double mem_free_limit = total_mem * (GCHeapFreeLimit/100.0); 457 const double mem_free_old_limit = max_old_gen_size * (GCHeapFreeLimit/100.0); 458 const double mem_free_eden_limit = max_eden_size * (GCHeapFreeLimit/100.0); 459 const double gc_cost_limit = GCTimeLimit/100.0; 460 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average()); 461 // But don't force a promo size below the current promo size. Otherwise, 462 // the promo size will shrink for no good reason. 463 promo_limit = MAX2(promo_limit, _promo_size); 464 465 466 if (PrintAdaptiveSizePolicy && (Verbose || 467 (free_in_old_gen < (size_t) mem_free_old_limit && 468 free_in_eden < (size_t) mem_free_eden_limit))) { 469 gclog_or_tty->print_cr( 470 "PSAdaptiveSizePolicy::check_gc_overhead_limit:" 471 " promo_limit: " SIZE_FORMAT 472 " max_eden_size: " SIZE_FORMAT 473 " total_free_limit: " SIZE_FORMAT 474 " max_old_gen_size: " SIZE_FORMAT 475 " max_eden_size: " SIZE_FORMAT 476 " mem_free_limit: " SIZE_FORMAT, 477 promo_limit, max_eden_size, total_free_limit, 478 max_old_gen_size, max_eden_size, 479 (size_t) mem_free_limit); 480 } 481 482 bool print_gc_overhead_limit_would_be_exceeded = false; 483 if (is_full_gc) { 484 if (gc_cost() > gc_cost_limit && 485 free_in_old_gen < (size_t) mem_free_old_limit && 486 free_in_eden < (size_t) mem_free_eden_limit) { 487 // Collections, on average, are taking too much time, and 488 // gc_cost() > gc_cost_limit 489 // we have too little space available after a full gc. 490 // total_free_limit < mem_free_limit 491 // where 492 // total_free_limit is the free space available in 493 // both generations 494 // total_mem is the total space available for allocation 495 // in both generations (survivor spaces are not included 496 // just as they are not included in eden_limit). 497 // mem_free_limit is a fraction of total_mem judged to be an 498 // acceptable amount that is still unused. 499 // The heap can ask for the value of this variable when deciding 500 // whether to thrown an OutOfMemory error. 501 // Note that the gc time limit test only works for the collections 502 // of the young gen + tenured gen and not for collections of the 503 // permanent gen. That is because the calculation of the space 504 // freed by the collection is the free space in the young gen + 505 // tenured gen. 506 // At this point the GC overhead limit is being exceeded. 507 inc_gc_overhead_limit_count(); 508 if (UseGCOverheadLimit) { 509 if (gc_overhead_limit_count() >= 510 AdaptiveSizePolicyGCTimeLimitThreshold){ 511 // All conditions have been met for throwing an out-of-memory 512 set_gc_overhead_limit_exceeded(true); 513 // Avoid consecutive OOM due to the gc time limit by resetting 514 // the counter. 515 reset_gc_overhead_limit_count(); 516 } else { 517 // The required consecutive collections which exceed the 518 // GC time limit may or may not have been reached. We 519 // are approaching that condition and so as not to 520 // throw an out-of-memory before all SoftRef's have been 521 // cleared, set _should_clear_all_soft_refs in CollectorPolicy. 522 // The clearing will be done on the next GC. 523 bool near_limit = gc_overhead_limit_near(); 524 if (near_limit) { 525 collector_policy->set_should_clear_all_soft_refs(true); 526 if (PrintGCDetails && Verbose) { 527 gclog_or_tty->print_cr(" Nearing GC overhead limit, " 528 "will be clearing all SoftReference"); 529 } 530 } 531 } 532 } 533 // Set this even when the overhead limit will not 534 // cause an out-of-memory. Diagnostic message indicating 535 // that the overhead limit is being exceeded is sometimes 536 // printed. 537 print_gc_overhead_limit_would_be_exceeded = true; 538 539 } else { 540 // Did not exceed overhead limits 541 reset_gc_overhead_limit_count(); 542 } 543 } 544 545 if (UseGCOverheadLimit && PrintGCDetails && Verbose) { 546 if (gc_overhead_limit_exceeded()) { 547 gclog_or_tty->print_cr(" GC is exceeding overhead limit " 548 "of %d%%", GCTimeLimit); 549 reset_gc_overhead_limit_count(); 550 } else if (print_gc_overhead_limit_would_be_exceeded) { 551 assert(gc_overhead_limit_count() > 0, "Should not be printing"); 552 gclog_or_tty->print_cr(" GC would exceed overhead limit " 553 "of %d%% %d consecutive time(s)", 554 GCTimeLimit, gc_overhead_limit_count()); 555 } 556 } 557 } 558 // Printing 559 560 bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const { 561 562 // Should only be used with adaptive size policy turned on. 563 // Otherwise, there may be variables that are undefined. 564 if (!UseAdaptiveSizePolicy) return false; 565 566 // Print goal for which action is needed. 567 char* action = NULL; 568 bool change_for_pause = false; 569 if ((change_old_gen_for_maj_pauses() == 570 decrease_old_gen_for_maj_pauses_true) || 571 (change_young_gen_for_min_pauses() == 572 decrease_young_gen_for_min_pauses_true)) { 573 action = (char*) " *** pause time goal ***"; 574 change_for_pause = true; 575 } else if ((change_old_gen_for_throughput() == 576 increase_old_gen_for_throughput_true) || 577 (change_young_gen_for_throughput() == 578 increase_young_gen_for_througput_true)) { 579 action = (char*) " *** throughput goal ***"; 580 } else if (decrease_for_footprint()) { 581 action = (char*) " *** reduced footprint ***"; 582 } else { 583 // No actions were taken. This can legitimately be the 584 // situation if not enough data has been gathered to make 585 // decisions. 586 return false; 587 } 588 589 // Pauses 590 // Currently the size of the old gen is only adjusted to 591 // change the major pause times. 592 char* young_gen_action = NULL; 593 char* tenured_gen_action = NULL; 594 595 char* shrink_msg = (char*) "(attempted to shrink)"; 596 char* grow_msg = (char*) "(attempted to grow)"; 597 char* no_change_msg = (char*) "(no change)"; 598 if (change_young_gen_for_min_pauses() == 599 decrease_young_gen_for_min_pauses_true) { 600 young_gen_action = shrink_msg; 601 } else if (change_for_pause) { 602 young_gen_action = no_change_msg; 603 } 604 605 if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) { 606 tenured_gen_action = shrink_msg; 607 } else if (change_for_pause) { 608 tenured_gen_action = no_change_msg; 609 } 610 611 // Throughput 612 if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) { 613 assert(change_young_gen_for_throughput() == 614 increase_young_gen_for_througput_true, 615 "Both generations should be growing"); 616 young_gen_action = grow_msg; 617 tenured_gen_action = grow_msg; 618 } else if (change_young_gen_for_throughput() == 619 increase_young_gen_for_througput_true) { 620 // Only the young generation may grow at start up (before 621 // enough full collections have been done to grow the old generation). 622 young_gen_action = grow_msg; 623 tenured_gen_action = no_change_msg; 624 } 625 626 // Minimum footprint 627 if (decrease_for_footprint() != 0) { 628 young_gen_action = shrink_msg; 629 tenured_gen_action = shrink_msg; 630 } 631 632 st->print_cr(" UseAdaptiveSizePolicy actions to meet %s", action); 633 st->print_cr(" GC overhead (%%)"); 634 st->print_cr(" Young generation: %7.2f\t %s", 635 100.0 * avg_minor_gc_cost()->average(), 636 young_gen_action); 637 st->print_cr(" Tenured generation: %7.2f\t %s", 638 100.0 * avg_major_gc_cost()->average(), 639 tenured_gen_action); 640 return true; 641 } 642 643 bool AdaptiveSizePolicy::print_adaptive_size_policy_on( 644 outputStream* st, 645 uint tenuring_threshold_arg) const { 646 if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) { 647 return false; 648 } 649 650 // Tenuring threshold 651 bool tenuring_threshold_changed = true; 652 if (decrement_tenuring_threshold_for_survivor_limit()) { 653 st->print(" Tenuring threshold: (attempted to decrease to avoid" 654 " survivor space overflow) = "); 655 } else if (decrement_tenuring_threshold_for_gc_cost()) { 656 st->print(" Tenuring threshold: (attempted to decrease to balance" 657 " GC costs) = "); 658 } else if (increment_tenuring_threshold_for_gc_cost()) { 659 st->print(" Tenuring threshold: (attempted to increase to balance" 660 " GC costs) = "); 661 } else { 662 tenuring_threshold_changed = false; 663 assert(!tenuring_threshold_change(), "(no change was attempted)"); 664 } 665 if (tenuring_threshold_changed) { 666 st->print_cr("%u", tenuring_threshold_arg); 667 } 668 return true; 669 }