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 throughput 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(): " UINTX_FORMAT " new_active_workers: " UINTX_FORMAT " " 172 "prev_active_workers: " UINTX_FORMAT "\n" 173 " active_workers_by_JT: " UINTX_FORMAT " active_workers_by_heap_size: " UINTX_FORMAT, 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 uintx min_workers = (total_workers == 1) ? 1 : 2; 197 new_active_workers = calc_default_active_workers(total_workers, 198 min_workers, 199 active_workers, 200 application_workers); 201 } 202 assert(new_active_workers > 0, "Always need at least 1"); 203 return new_active_workers; 204 } 205 206 int AdaptiveSizePolicy::calc_active_conc_workers(uintx total_workers, 207 uintx active_workers, 208 uintx application_workers) { 209 if (!UseDynamicNumberOfGCThreads || 210 (!FLAG_IS_DEFAULT(ConcGCThreads) && !ForceDynamicNumberOfGCThreads)) { 211 return ConcGCThreads; 212 } else { 213 int no_of_gc_threads = calc_default_active_workers( 214 total_workers, 215 1, /* Minimum number of workers */ 216 active_workers, 217 application_workers); 218 return no_of_gc_threads; 219 } 220 } 221 222 bool AdaptiveSizePolicy::tenuring_threshold_change() const { 223 return decrement_tenuring_threshold_for_gc_cost() || 224 increment_tenuring_threshold_for_gc_cost() || 225 decrement_tenuring_threshold_for_survivor_limit(); 226 } 227 228 void AdaptiveSizePolicy::minor_collection_begin() { 229 // Update the interval time 230 _minor_timer.stop(); 231 // Save most recent collection time 232 _latest_minor_mutator_interval_seconds = _minor_timer.seconds(); 233 _minor_timer.reset(); 234 _minor_timer.start(); 235 } 236 237 void AdaptiveSizePolicy::update_minor_pause_young_estimator( 238 double minor_pause_in_ms) { 239 double eden_size_in_mbytes = ((double)_eden_size)/((double)M); 240 _minor_pause_young_estimator->update(eden_size_in_mbytes, 241 minor_pause_in_ms); 242 } 243 244 void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) { 245 // Update the pause time. 246 _minor_timer.stop(); 247 248 if (gc_cause != GCCause::_java_lang_system_gc || 249 UseAdaptiveSizePolicyWithSystemGC) { 250 double minor_pause_in_seconds = _minor_timer.seconds(); 251 double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS; 252 253 // Sample for performance counter 254 _avg_minor_pause->sample(minor_pause_in_seconds); 255 256 // Cost of collection (unit-less) 257 double collection_cost = 0.0; 258 if ((_latest_minor_mutator_interval_seconds > 0.0) && 259 (minor_pause_in_seconds > 0.0)) { 260 double interval_in_seconds = 261 _latest_minor_mutator_interval_seconds + minor_pause_in_seconds; 262 collection_cost = 263 minor_pause_in_seconds / interval_in_seconds; 264 _avg_minor_gc_cost->sample(collection_cost); 265 // Sample for performance counter 266 _avg_minor_interval->sample(interval_in_seconds); 267 } 268 269 // The policy does not have enough data until at least some 270 // minor collections have been done. 271 _young_gen_policy_is_ready = 272 (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold); 273 274 // Calculate variables used to estimate pause time vs. gen sizes 275 double eden_size_in_mbytes = ((double)_eden_size)/((double)M); 276 update_minor_pause_young_estimator(minor_pause_in_ms); 277 update_minor_pause_old_estimator(minor_pause_in_ms); 278 279 if (PrintAdaptiveSizePolicy && Verbose) { 280 gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: " 281 "minor gc cost: %f average: %f", collection_cost, 282 _avg_minor_gc_cost->average()); 283 gclog_or_tty->print_cr(" minor pause: %f minor period %f", 284 minor_pause_in_ms, 285 _latest_minor_mutator_interval_seconds * MILLIUNITS); 286 } 287 288 // Calculate variable used to estimate collection cost vs. gen sizes 289 assert(collection_cost >= 0.0, "Expected to be non-negative"); 290 _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost); 291 } 292 293 // Interval times use this timer to measure the mutator time. 294 // Reset the timer after the GC pause. 295 _minor_timer.reset(); 296 _minor_timer.start(); 297 } 298 299 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden, 300 uint percent_change) { 301 size_t eden_heap_delta; 302 eden_heap_delta = cur_eden / 100 * percent_change; 303 return eden_heap_delta; 304 } 305 306 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) { 307 return eden_increment(cur_eden, YoungGenerationSizeIncrement); 308 } 309 310 size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) { 311 size_t eden_heap_delta = eden_increment(cur_eden) / 312 AdaptiveSizeDecrementScaleFactor; 313 return eden_heap_delta; 314 } 315 316 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo, 317 uint percent_change) { 318 size_t promo_heap_delta; 319 promo_heap_delta = cur_promo / 100 * percent_change; 320 return promo_heap_delta; 321 } 322 323 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) { 324 return promo_increment(cur_promo, TenuredGenerationSizeIncrement); 325 } 326 327 size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) { 328 size_t promo_heap_delta = promo_increment(cur_promo); 329 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor; 330 return promo_heap_delta; 331 } 332 333 double AdaptiveSizePolicy::time_since_major_gc() const { 334 _major_timer.stop(); 335 double result = _major_timer.seconds(); 336 _major_timer.start(); 337 return result; 338 } 339 340 // Linear decay of major gc cost 341 double AdaptiveSizePolicy::decaying_major_gc_cost() const { 342 double major_interval = major_gc_interval_average_for_decay(); 343 double major_gc_cost_average = major_gc_cost(); 344 double decayed_major_gc_cost = major_gc_cost_average; 345 if(time_since_major_gc() > 0.0) { 346 decayed_major_gc_cost = major_gc_cost() * 347 (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval) 348 / time_since_major_gc(); 349 } 350 351 // The decayed cost should always be smaller than the 352 // average cost but the vagaries of finite arithmetic could 353 // produce a larger value in decayed_major_gc_cost so protect 354 // against that. 355 return MIN2(major_gc_cost_average, decayed_major_gc_cost); 356 } 357 358 // Use a value of the major gc cost that has been decayed 359 // by the factor 360 // 361 // average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale / 362 // time-since-last-major-gc 363 // 364 // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale 365 // is less than time-since-last-major-gc. 366 // 367 // In cases where there are initial major gc's that 368 // are of a relatively high cost but no later major 369 // gc's, the total gc cost can remain high because 370 // the major gc cost remains unchanged (since there are no major 371 // gc's). In such a situation the value of the unchanging 372 // major gc cost can keep the mutator throughput below 373 // the goal when in fact the major gc cost is becoming diminishingly 374 // small. Use the decaying gc cost only to decide whether to 375 // adjust for throughput. Using it also to determine the adjustment 376 // to be made for throughput also seems reasonable but there is 377 // no test case to use to decide if it is the right thing to do 378 // don't do it yet. 379 380 double AdaptiveSizePolicy::decaying_gc_cost() const { 381 double decayed_major_gc_cost = major_gc_cost(); 382 double avg_major_interval = major_gc_interval_average_for_decay(); 383 if (UseAdaptiveSizeDecayMajorGCCost && 384 (AdaptiveSizeMajorGCDecayTimeScale > 0) && 385 (avg_major_interval > 0.00)) { 386 double time_since_last_major_gc = time_since_major_gc(); 387 388 // Decay the major gc cost? 389 if (time_since_last_major_gc > 390 ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) { 391 392 // Decay using the time-since-last-major-gc 393 decayed_major_gc_cost = decaying_major_gc_cost(); 394 if (PrintGCDetails && Verbose) { 395 gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:" 396 " %f time since last major gc: %f", 397 avg_major_interval, time_since_last_major_gc); 398 gclog_or_tty->print_cr(" major gc cost: %f decayed major gc cost: %f", 399 major_gc_cost(), decayed_major_gc_cost); 400 } 401 } 402 } 403 double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost()); 404 return result; 405 } 406 407 408 void AdaptiveSizePolicy::clear_generation_free_space_flags() { 409 set_change_young_gen_for_min_pauses(0); 410 set_change_old_gen_for_maj_pauses(0); 411 412 set_change_old_gen_for_throughput(0); 413 set_change_young_gen_for_throughput(0); 414 set_decrease_for_footprint(0); 415 set_decide_at_full_gc(0); 416 } 417 418 void AdaptiveSizePolicy::check_gc_overhead_limit( 419 size_t young_live, 420 size_t eden_live, 421 size_t max_old_gen_size, 422 size_t max_eden_size, 423 bool is_full_gc, 424 GCCause::Cause gc_cause, 425 CollectorPolicy* collector_policy) { 426 427 // Ignore explicit GC's. Exiting here does not set the flag and 428 // does not reset the count. Updating of the averages for system 429 // GC's is still controlled by UseAdaptiveSizePolicyWithSystemGC. 430 if (GCCause::is_user_requested_gc(gc_cause) || 431 GCCause::is_serviceability_requested_gc(gc_cause)) { 432 return; 433 } 434 // eden_limit is the upper limit on the size of eden based on 435 // the maximum size of the young generation and the sizes 436 // of the survivor space. 437 // The question being asked is whether the gc costs are high 438 // and the space being recovered by a collection is low. 439 // free_in_young_gen is the free space in the young generation 440 // after a collection and promo_live is the free space in the old 441 // generation after a collection. 442 // 443 // Use the minimum of the current value of the live in the 444 // young gen or the average of the live in the young gen. 445 // If the current value drops quickly, that should be taken 446 // into account (i.e., don't trigger if the amount of free 447 // space has suddenly jumped up). If the current is much 448 // higher than the average, use the average since it represents 449 // the longer term behavior. 450 const size_t live_in_eden = 451 MIN2(eden_live, (size_t) avg_eden_live()->average()); 452 const size_t free_in_eden = max_eden_size > live_in_eden ? 453 max_eden_size - live_in_eden : 0; 454 const size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average()); 455 const size_t total_free_limit = free_in_old_gen + free_in_eden; 456 const size_t total_mem = max_old_gen_size + max_eden_size; 457 const double mem_free_limit = total_mem * (GCHeapFreeLimit/100.0); 458 const double mem_free_old_limit = max_old_gen_size * (GCHeapFreeLimit/100.0); 459 const double mem_free_eden_limit = max_eden_size * (GCHeapFreeLimit/100.0); 460 const double gc_cost_limit = GCTimeLimit/100.0; 461 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average()); 462 // But don't force a promo size below the current promo size. Otherwise, 463 // the promo size will shrink for no good reason. 464 promo_limit = MAX2(promo_limit, _promo_size); 465 466 467 if (PrintAdaptiveSizePolicy && (Verbose || 468 (free_in_old_gen < (size_t) mem_free_old_limit && 469 free_in_eden < (size_t) mem_free_eden_limit))) { 470 gclog_or_tty->print_cr( 471 "PSAdaptiveSizePolicy::check_gc_overhead_limit:" 472 " promo_limit: " SIZE_FORMAT 473 " max_eden_size: " SIZE_FORMAT 474 " total_free_limit: " SIZE_FORMAT 475 " max_old_gen_size: " SIZE_FORMAT 476 " max_eden_size: " SIZE_FORMAT 477 " mem_free_limit: " SIZE_FORMAT, 478 promo_limit, max_eden_size, total_free_limit, 479 max_old_gen_size, max_eden_size, 480 (size_t) mem_free_limit); 481 } 482 483 bool print_gc_overhead_limit_would_be_exceeded = false; 484 if (is_full_gc) { 485 if (gc_cost() > gc_cost_limit && 486 free_in_old_gen < (size_t) mem_free_old_limit && 487 free_in_eden < (size_t) mem_free_eden_limit) { 488 // Collections, on average, are taking too much time, and 489 // gc_cost() > gc_cost_limit 490 // we have too little space available after a full gc. 491 // total_free_limit < mem_free_limit 492 // where 493 // total_free_limit is the free space available in 494 // both generations 495 // total_mem is the total space available for allocation 496 // in both generations (survivor spaces are not included 497 // just as they are not included in eden_limit). 498 // mem_free_limit is a fraction of total_mem judged to be an 499 // acceptable amount that is still unused. 500 // The heap can ask for the value of this variable when deciding 501 // whether to thrown an OutOfMemory error. 502 // Note that the gc time limit test only works for the collections 503 // of the young gen + tenured gen and not for collections of the 504 // permanent gen. That is because the calculation of the space 505 // freed by the collection is the free space in the young gen + 506 // tenured gen. 507 // At this point the GC overhead limit is being exceeded. 508 inc_gc_overhead_limit_count(); 509 if (UseGCOverheadLimit) { 510 if (gc_overhead_limit_count() >= 511 AdaptiveSizePolicyGCTimeLimitThreshold){ 512 // All conditions have been met for throwing an out-of-memory 513 set_gc_overhead_limit_exceeded(true); 514 // Avoid consecutive OOM due to the gc time limit by resetting 515 // the counter. 516 reset_gc_overhead_limit_count(); 517 } else { 518 // The required consecutive collections which exceed the 519 // GC time limit may or may not have been reached. We 520 // are approaching that condition and so as not to 521 // throw an out-of-memory before all SoftRef's have been 522 // cleared, set _should_clear_all_soft_refs in CollectorPolicy. 523 // The clearing will be done on the next GC. 524 bool near_limit = gc_overhead_limit_near(); 525 if (near_limit) { 526 collector_policy->set_should_clear_all_soft_refs(true); 527 if (PrintGCDetails && Verbose) { 528 gclog_or_tty->print_cr(" Nearing GC overhead limit, " 529 "will be clearing all SoftReference"); 530 } 531 } 532 } 533 } 534 // Set this even when the overhead limit will not 535 // cause an out-of-memory. Diagnostic message indicating 536 // that the overhead limit is being exceeded is sometimes 537 // printed. 538 print_gc_overhead_limit_would_be_exceeded = true; 539 540 } else { 541 // Did not exceed overhead limits 542 reset_gc_overhead_limit_count(); 543 } 544 } 545 546 if (UseGCOverheadLimit && PrintGCDetails && Verbose) { 547 if (gc_overhead_limit_exceeded()) { 548 gclog_or_tty->print_cr(" GC is exceeding overhead limit " 549 "of " UINTX_FORMAT "%%", GCTimeLimit); 550 reset_gc_overhead_limit_count(); 551 } else if (print_gc_overhead_limit_would_be_exceeded) { 552 assert(gc_overhead_limit_count() > 0, "Should not be printing"); 553 gclog_or_tty->print_cr(" GC would exceed overhead limit " 554 "of " UINTX_FORMAT "%% %d consecutive time(s)", 555 GCTimeLimit, gc_overhead_limit_count()); 556 } 557 } 558 } 559 // Printing 560 561 bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const { 562 563 // Should only be used with adaptive size policy turned on. 564 // Otherwise, there may be variables that are undefined. 565 if (!UseAdaptiveSizePolicy) return false; 566 567 // Print goal for which action is needed. 568 char* action = NULL; 569 bool change_for_pause = false; 570 if ((change_old_gen_for_maj_pauses() == 571 decrease_old_gen_for_maj_pauses_true) || 572 (change_young_gen_for_min_pauses() == 573 decrease_young_gen_for_min_pauses_true)) { 574 action = (char*) " *** pause time goal ***"; 575 change_for_pause = true; 576 } else if ((change_old_gen_for_throughput() == 577 increase_old_gen_for_throughput_true) || 578 (change_young_gen_for_throughput() == 579 increase_young_gen_for_througput_true)) { 580 action = (char*) " *** throughput goal ***"; 581 } else if (decrease_for_footprint()) { 582 action = (char*) " *** reduced footprint ***"; 583 } else { 584 // No actions were taken. This can legitimately be the 585 // situation if not enough data has been gathered to make 586 // decisions. 587 return false; 588 } 589 590 // Pauses 591 // Currently the size of the old gen is only adjusted to 592 // change the major pause times. 593 char* young_gen_action = NULL; 594 char* tenured_gen_action = NULL; 595 596 char* shrink_msg = (char*) "(attempted to shrink)"; 597 char* grow_msg = (char*) "(attempted to grow)"; 598 char* no_change_msg = (char*) "(no change)"; 599 if (change_young_gen_for_min_pauses() == 600 decrease_young_gen_for_min_pauses_true) { 601 young_gen_action = shrink_msg; 602 } else if (change_for_pause) { 603 young_gen_action = no_change_msg; 604 } 605 606 if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) { 607 tenured_gen_action = shrink_msg; 608 } else if (change_for_pause) { 609 tenured_gen_action = no_change_msg; 610 } 611 612 // Throughput 613 if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) { 614 assert(change_young_gen_for_throughput() == 615 increase_young_gen_for_througput_true, 616 "Both generations should be growing"); 617 young_gen_action = grow_msg; 618 tenured_gen_action = grow_msg; 619 } else if (change_young_gen_for_throughput() == 620 increase_young_gen_for_througput_true) { 621 // Only the young generation may grow at start up (before 622 // enough full collections have been done to grow the old generation). 623 young_gen_action = grow_msg; 624 tenured_gen_action = no_change_msg; 625 } 626 627 // Minimum footprint 628 if (decrease_for_footprint() != 0) { 629 young_gen_action = shrink_msg; 630 tenured_gen_action = shrink_msg; 631 } 632 633 st->print_cr(" UseAdaptiveSizePolicy actions to meet %s", action); 634 st->print_cr(" GC overhead (%%)"); 635 st->print_cr(" Young generation: %7.2f\t %s", 636 100.0 * avg_minor_gc_cost()->average(), 637 young_gen_action); 638 st->print_cr(" Tenured generation: %7.2f\t %s", 639 100.0 * avg_major_gc_cost()->average(), 640 tenured_gen_action); 641 return true; 642 } 643 644 bool AdaptiveSizePolicy::print_adaptive_size_policy_on( 645 outputStream* st, 646 uint tenuring_threshold_arg) const { 647 if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) { 648 return false; 649 } 650 651 // Tenuring threshold 652 bool tenuring_threshold_changed = true; 653 if (decrement_tenuring_threshold_for_survivor_limit()) { 654 st->print(" Tenuring threshold: (attempted to decrease to avoid" 655 " survivor space overflow) = "); 656 } else if (decrement_tenuring_threshold_for_gc_cost()) { 657 st->print(" Tenuring threshold: (attempted to decrease to balance" 658 " GC costs) = "); 659 } else if (increment_tenuring_threshold_for_gc_cost()) { 660 st->print(" Tenuring threshold: (attempted to increase to balance" 661 " GC costs) = "); 662 } else { 663 tenuring_threshold_changed = false; 664 assert(!tenuring_threshold_change(), "(no change was attempted)"); 665 } 666 if (tenuring_threshold_changed) { 667 st->print_cr("%u", tenuring_threshold_arg); 668 } 669 return true; 670 }