src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp

Fri, 31 May 2013 14:32:44 +0200

author
stefank
date
Fri, 31 May 2013 14:32:44 +0200
changeset 5515
9766f73e770d
parent 5279
493089fd29df
child 5819
c49c7f835e8d
permissions
-rw-r--r--

8022880: False sharing between PSPromotionManager instances
Summary: Pad the PSPromotionManager instances in the manager array.
Reviewed-by: brutisso, jmasa

duke@435 1 /*
tamao@5120 2 * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
duke@435 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435 4 *
duke@435 5 * This code is free software; you can redistribute it and/or modify it
duke@435 6 * under the terms of the GNU General Public License version 2 only, as
duke@435 7 * published by the Free Software Foundation.
duke@435 8 *
duke@435 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@435 13 * accompanied this code).
duke@435 14 *
duke@435 15 * You should have received a copy of the GNU General Public License version
duke@435 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@435 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435 18 *
trims@1907 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907 20 * or visit www.oracle.com if you need additional information or have any
trims@1907 21 * questions.
duke@435 22 *
duke@435 23 */
duke@435 24
stefank@2314 25 #include "precompiled.hpp"
stefank@2314 26 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
stefank@2314 27 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
stefank@2314 28 #include "gc_implementation/parallelScavenge/psGCAdaptivePolicyCounters.hpp"
stefank@2314 29 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
stefank@2314 30 #include "gc_implementation/shared/gcPolicyCounters.hpp"
stefank@2314 31 #include "gc_interface/gcCause.hpp"
stefank@2314 32 #include "memory/collectorPolicy.hpp"
stefank@2314 33 #include "runtime/timer.hpp"
stefank@2314 34 #include "utilities/top.hpp"
duke@435 35
duke@435 36 #include <math.h>
duke@435 37
duke@435 38 PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size,
duke@435 39 size_t init_promo_size,
duke@435 40 size_t init_survivor_size,
duke@435 41 size_t intra_generation_alignment,
duke@435 42 double gc_pause_goal_sec,
duke@435 43 double gc_minor_pause_goal_sec,
duke@435 44 uint gc_cost_ratio) :
duke@435 45 AdaptiveSizePolicy(init_eden_size,
duke@435 46 init_promo_size,
duke@435 47 init_survivor_size,
duke@435 48 gc_pause_goal_sec,
duke@435 49 gc_cost_ratio),
duke@435 50 _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin/
duke@435 51 100.0),
duke@435 52 _intra_generation_alignment(intra_generation_alignment),
duke@435 53 _live_at_last_full_gc(init_promo_size),
duke@435 54 _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec),
duke@435 55 _latest_major_mutator_interval_seconds(0),
duke@435 56 _young_gen_change_for_major_pause_count(0)
duke@435 57 {
duke@435 58 // Sizing policy statistics
duke@435 59 _avg_major_pause =
duke@435 60 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
duke@435 61 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435 62 _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435 63
duke@435 64 _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
duke@435 65 _major_pause_old_estimator =
duke@435 66 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435 67 _major_pause_young_estimator =
duke@435 68 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435 69 _major_collection_estimator =
duke@435 70 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435 71
duke@435 72 _young_gen_size_increment_supplement = YoungGenerationSizeSupplement;
duke@435 73 _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement;
duke@435 74
duke@435 75 // Start the timers
duke@435 76 _major_timer.start();
duke@435 77
duke@435 78 _old_gen_policy_is_ready = false;
duke@435 79 }
duke@435 80
duke@435 81 void PSAdaptiveSizePolicy::major_collection_begin() {
duke@435 82 // Update the interval time
duke@435 83 _major_timer.stop();
duke@435 84 // Save most recent collection time
duke@435 85 _latest_major_mutator_interval_seconds = _major_timer.seconds();
duke@435 86 _major_timer.reset();
duke@435 87 _major_timer.start();
duke@435 88 }
duke@435 89
duke@435 90 void PSAdaptiveSizePolicy::update_minor_pause_old_estimator(
duke@435 91 double minor_pause_in_ms) {
duke@435 92 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
duke@435 93 _minor_pause_old_estimator->update(promo_size_in_mbytes,
duke@435 94 minor_pause_in_ms);
duke@435 95 }
duke@435 96
duke@435 97 void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live,
duke@435 98 GCCause::Cause gc_cause) {
duke@435 99 // Update the pause time.
duke@435 100 _major_timer.stop();
duke@435 101
duke@435 102 if (gc_cause != GCCause::_java_lang_system_gc ||
duke@435 103 UseAdaptiveSizePolicyWithSystemGC) {
duke@435 104 double major_pause_in_seconds = _major_timer.seconds();
duke@435 105 double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS;
duke@435 106
duke@435 107 // Sample for performance counter
duke@435 108 _avg_major_pause->sample(major_pause_in_seconds);
duke@435 109
duke@435 110 // Cost of collection (unit-less)
duke@435 111 double collection_cost = 0.0;
duke@435 112 if ((_latest_major_mutator_interval_seconds > 0.0) &&
duke@435 113 (major_pause_in_seconds > 0.0)) {
duke@435 114 double interval_in_seconds =
duke@435 115 _latest_major_mutator_interval_seconds + major_pause_in_seconds;
duke@435 116 collection_cost =
duke@435 117 major_pause_in_seconds / interval_in_seconds;
duke@435 118 avg_major_gc_cost()->sample(collection_cost);
duke@435 119
duke@435 120 // Sample for performance counter
duke@435 121 _avg_major_interval->sample(interval_in_seconds);
duke@435 122 }
duke@435 123
duke@435 124 // Calculate variables used to estimate pause time vs. gen sizes
duke@435 125 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
duke@435 126 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
duke@435 127 _major_pause_old_estimator->update(promo_size_in_mbytes,
duke@435 128 major_pause_in_ms);
duke@435 129 _major_pause_young_estimator->update(eden_size_in_mbytes,
duke@435 130 major_pause_in_ms);
duke@435 131
duke@435 132 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 133 gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: "
duke@435 134 "major gc cost: %f average: %f", collection_cost,
duke@435 135 avg_major_gc_cost()->average());
duke@435 136 gclog_or_tty->print_cr(" major pause: %f major period %f",
duke@435 137 major_pause_in_ms,
duke@435 138 _latest_major_mutator_interval_seconds * MILLIUNITS);
duke@435 139 }
duke@435 140
duke@435 141 // Calculate variable used to estimate collection cost vs. gen sizes
duke@435 142 assert(collection_cost >= 0.0, "Expected to be non-negative");
duke@435 143 _major_collection_estimator->update(promo_size_in_mbytes,
duke@435 144 collection_cost);
duke@435 145 }
duke@435 146
duke@435 147 // Update the amount live at the end of a full GC
duke@435 148 _live_at_last_full_gc = amount_live;
duke@435 149
duke@435 150 // The policy does not have enough data until at least some major collections
duke@435 151 // have been done.
duke@435 152 if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) {
duke@435 153 _old_gen_policy_is_ready = true;
duke@435 154 }
duke@435 155
duke@435 156 // Interval times use this timer to measure the interval that
duke@435 157 // the mutator runs. Reset after the GC pause has been measured.
duke@435 158 _major_timer.reset();
duke@435 159 _major_timer.start();
duke@435 160 }
duke@435 161
duke@435 162 // If the remaining free space in the old generation is less that
duke@435 163 // that expected to be needed by the next collection, do a full
duke@435 164 // collection now.
duke@435 165 bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) {
duke@435 166
duke@435 167 // A similar test is done in the scavenge's should_attempt_scavenge(). If
duke@435 168 // this is changed, decide if that test should also be changed.
duke@435 169 bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes;
duke@435 170 if (PrintGCDetails && Verbose) {
duke@435 171 if (result) {
duke@435 172 gclog_or_tty->print(" full after scavenge: ");
duke@435 173 } else {
duke@435 174 gclog_or_tty->print(" no full after scavenge: ");
duke@435 175 }
duke@435 176 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
duke@435 177 " padded_average_promoted " SIZE_FORMAT
duke@435 178 " free in old gen " SIZE_FORMAT,
duke@435 179 (size_t) average_promoted_in_bytes(),
duke@435 180 (size_t) padded_average_promoted_in_bytes(),
duke@435 181 old_free_in_bytes);
duke@435 182 }
duke@435 183 return result;
duke@435 184 }
duke@435 185
duke@435 186 void PSAdaptiveSizePolicy::clear_generation_free_space_flags() {
duke@435 187
duke@435 188 AdaptiveSizePolicy::clear_generation_free_space_flags();
duke@435 189
duke@435 190 set_change_old_gen_for_min_pauses(0);
duke@435 191
duke@435 192 set_change_young_gen_for_maj_pauses(0);
duke@435 193 }
duke@435 194
duke@435 195 // If this is not a full GC, only test and modify the young generation.
duke@435 196
tamao@5192 197 void PSAdaptiveSizePolicy::compute_generations_free_space(
jmasa@1822 198 size_t young_live,
jmasa@1822 199 size_t eden_live,
jmasa@1822 200 size_t old_live,
jmasa@1822 201 size_t cur_eden,
jmasa@1822 202 size_t max_old_gen_size,
jmasa@1822 203 size_t max_eden_size,
tamao@5120 204 bool is_full_gc) {
tamao@5120 205 compute_eden_space_size(young_live,
tamao@5120 206 eden_live,
tamao@5120 207 cur_eden,
tamao@5120 208 max_eden_size,
tamao@5120 209 is_full_gc);
tamao@5120 210
tamao@5120 211 compute_old_gen_free_space(old_live,
tamao@5120 212 cur_eden,
tamao@5120 213 max_old_gen_size,
tamao@5120 214 is_full_gc);
tamao@5120 215 }
tamao@5120 216
tamao@5120 217 void PSAdaptiveSizePolicy::compute_eden_space_size(
tamao@5120 218 size_t young_live,
tamao@5120 219 size_t eden_live,
tamao@5120 220 size_t cur_eden,
tamao@5120 221 size_t max_eden_size,
tamao@5120 222 bool is_full_gc) {
duke@435 223
duke@435 224 // Update statistics
duke@435 225 // Time statistics are updated as we go, update footprint stats here
coleenp@4037 226 _avg_base_footprint->sample(BaseFootPrintEstimate);
duke@435 227 avg_young_live()->sample(young_live);
duke@435 228 avg_eden_live()->sample(eden_live);
tamao@5120 229
tamao@5120 230 // This code used to return if the policy was not ready , i.e.,
tamao@5120 231 // policy_is_ready() returning false. The intent was that
tamao@5120 232 // decisions below needed major collection times and so could
tamao@5120 233 // not be made before two major collections. A consequence was
tamao@5120 234 // adjustments to the young generation were not done until after
tamao@5120 235 // two major collections even if the minor collections times
tamao@5120 236 // exceeded the requested goals. Now let the young generation
tamao@5120 237 // adjust for the minor collection times. Major collection times
tamao@5120 238 // will be zero for the first collection and will naturally be
tamao@5120 239 // ignored. Tenured generation adjustments are only made at the
tamao@5120 240 // full collections so until the second major collection has
tamao@5120 241 // been reached, no tenured generation adjustments will be made.
tamao@5120 242
tamao@5120 243 // Until we know better, desired promotion size uses the last calculation
tamao@5120 244 size_t desired_promo_size = _promo_size;
tamao@5120 245
tamao@5120 246 // Start eden at the current value. The desired value that is stored
tamao@5120 247 // in _eden_size is not bounded by constraints of the heap and can
tamao@5120 248 // run away.
tamao@5120 249 //
tamao@5120 250 // As expected setting desired_eden_size to the current
tamao@5120 251 // value of desired_eden_size as a starting point
tamao@5120 252 // caused desired_eden_size to grow way too large and caused
tamao@5120 253 // an overflow down stream. It may have improved performance in
tamao@5120 254 // some case but is dangerous.
tamao@5120 255 size_t desired_eden_size = cur_eden;
tamao@5120 256
tamao@5120 257 // Cache some values. There's a bit of work getting these, so
tamao@5120 258 // we might save a little time.
tamao@5120 259 const double major_cost = major_gc_cost();
tamao@5120 260 const double minor_cost = minor_gc_cost();
tamao@5120 261
tamao@5120 262 // This method sets the desired eden size. That plus the
tamao@5120 263 // desired survivor space sizes sets the desired young generation
tamao@5120 264 // size. This methods does not know what the desired survivor
tamao@5120 265 // size is but expects that other policy will attempt to make
tamao@5120 266 // the survivor sizes compatible with the live data in the
tamao@5120 267 // young generation. This limit is an estimate of the space left
tamao@5120 268 // in the young generation after the survivor spaces have been
tamao@5120 269 // subtracted out.
tamao@5120 270 size_t eden_limit = max_eden_size;
tamao@5120 271
tamao@5120 272 const double gc_cost_limit = GCTimeLimit/100.0;
tamao@5120 273
tamao@5120 274 // Which way should we go?
tamao@5120 275 // if pause requirement is not met
tamao@5120 276 // adjust size of any generation with average paus exceeding
tamao@5120 277 // the pause limit. Adjust one pause at a time (the larger)
tamao@5120 278 // and only make adjustments for the major pause at full collections.
tamao@5120 279 // else if throughput requirement not met
tamao@5120 280 // adjust the size of the generation with larger gc time. Only
tamao@5120 281 // adjust one generation at a time.
tamao@5120 282 // else
tamao@5120 283 // adjust down the total heap size. Adjust down the larger of the
tamao@5120 284 // generations.
tamao@5120 285
tamao@5120 286 // Add some checks for a threshold for a change. For example,
tamao@5120 287 // a change less than the necessary alignment is probably not worth
tamao@5120 288 // attempting.
tamao@5120 289
tamao@5120 290
tamao@5120 291 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
tamao@5120 292 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
tamao@5120 293 //
tamao@5120 294 // Check pauses
tamao@5120 295 //
tamao@5120 296 // Make changes only to affect one of the pauses (the larger)
tamao@5120 297 // at a time.
tamao@5120 298 adjust_eden_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
tamao@5120 299
tamao@5120 300 } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
tamao@5120 301 // Adjust only for the minor pause time goal
tamao@5120 302 adjust_eden_for_minor_pause_time(is_full_gc, &desired_eden_size);
tamao@5120 303
tamao@5120 304 } else if(adjusted_mutator_cost() < _throughput_goal) {
tamao@5120 305 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
tamao@5120 306 // This sometimes resulted in skipping to the minimize footprint
tamao@5120 307 // code. Change this to try and reduce GC time if mutator time is
tamao@5120 308 // negative for whatever reason. Or for future consideration,
tamao@5120 309 // bail out of the code if mutator time is negative.
tamao@5120 310 //
tamao@5120 311 // Throughput
tamao@5120 312 //
tamao@5120 313 assert(major_cost >= 0.0, "major cost is < 0.0");
tamao@5120 314 assert(minor_cost >= 0.0, "minor cost is < 0.0");
tamao@5120 315 // Try to reduce the GC times.
tamao@5120 316 adjust_eden_for_throughput(is_full_gc, &desired_eden_size);
tamao@5120 317
tamao@5120 318 } else {
tamao@5120 319
tamao@5120 320 // Be conservative about reducing the footprint.
tamao@5120 321 // Do a minimum number of major collections first.
tamao@5120 322 // Have reasonable averages for major and minor collections costs.
tamao@5120 323 if (UseAdaptiveSizePolicyFootprintGoal &&
tamao@5120 324 young_gen_policy_is_ready() &&
tamao@5120 325 avg_major_gc_cost()->average() >= 0.0 &&
tamao@5120 326 avg_minor_gc_cost()->average() >= 0.0) {
tamao@5120 327 size_t desired_sum = desired_eden_size + desired_promo_size;
tamao@5120 328 desired_eden_size = adjust_eden_for_footprint(desired_eden_size, desired_sum);
tamao@5120 329 }
tamao@5120 330 }
tamao@5120 331
tamao@5120 332 // Note we make the same tests as in the code block below; the code
tamao@5120 333 // seems a little easier to read with the printing in another block.
tamao@5120 334 if (PrintAdaptiveSizePolicy) {
tamao@5120 335 if (desired_eden_size > eden_limit) {
tamao@5120 336 gclog_or_tty->print_cr(
tamao@5120 337 "PSAdaptiveSizePolicy::compute_eden_space_size limits:"
tamao@5120 338 " desired_eden_size: " SIZE_FORMAT
tamao@5120 339 " old_eden_size: " SIZE_FORMAT
tamao@5120 340 " eden_limit: " SIZE_FORMAT
tamao@5120 341 " cur_eden: " SIZE_FORMAT
tamao@5120 342 " max_eden_size: " SIZE_FORMAT
tamao@5120 343 " avg_young_live: " SIZE_FORMAT,
tamao@5120 344 desired_eden_size, _eden_size, eden_limit, cur_eden,
tamao@5120 345 max_eden_size, (size_t)avg_young_live()->average());
tamao@5120 346 }
tamao@5120 347 if (gc_cost() > gc_cost_limit) {
tamao@5120 348 gclog_or_tty->print_cr(
tamao@5120 349 "PSAdaptiveSizePolicy::compute_eden_space_size: gc time limit"
tamao@5120 350 " gc_cost: %f "
tamao@5120 351 " GCTimeLimit: %d",
tamao@5120 352 gc_cost(), GCTimeLimit);
tamao@5120 353 }
tamao@5120 354 }
tamao@5120 355
tamao@5120 356 // Align everything and make a final limit check
tamao@5120 357 const size_t alignment = _intra_generation_alignment;
tamao@5120 358 desired_eden_size = align_size_up(desired_eden_size, alignment);
tamao@5120 359 desired_eden_size = MAX2(desired_eden_size, alignment);
tamao@5120 360
tamao@5120 361 eden_limit = align_size_down(eden_limit, alignment);
tamao@5120 362
tamao@5120 363 // And one last limit check, now that we've aligned things.
tamao@5120 364 if (desired_eden_size > eden_limit) {
tamao@5120 365 // If the policy says to get a larger eden but
tamao@5120 366 // is hitting the limit, don't decrease eden.
tamao@5120 367 // This can lead to a general drifting down of the
tamao@5120 368 // eden size. Let the tenuring calculation push more
tamao@5120 369 // into the old gen.
tamao@5120 370 desired_eden_size = MAX2(eden_limit, cur_eden);
tamao@5120 371 }
tamao@5120 372
tamao@5120 373 if (PrintAdaptiveSizePolicy) {
tamao@5120 374 // Timing stats
tamao@5120 375 gclog_or_tty->print(
tamao@5120 376 "PSAdaptiveSizePolicy::compute_eden_space_size: costs"
tamao@5120 377 " minor_time: %f"
tamao@5120 378 " major_cost: %f"
tamao@5120 379 " mutator_cost: %f"
tamao@5120 380 " throughput_goal: %f",
tamao@5120 381 minor_gc_cost(), major_gc_cost(), mutator_cost(),
tamao@5120 382 _throughput_goal);
tamao@5120 383
tamao@5120 384 // We give more details if Verbose is set
tamao@5120 385 if (Verbose) {
tamao@5120 386 gclog_or_tty->print( " minor_pause: %f"
tamao@5120 387 " major_pause: %f"
tamao@5120 388 " minor_interval: %f"
tamao@5120 389 " major_interval: %f"
tamao@5120 390 " pause_goal: %f",
tamao@5120 391 _avg_minor_pause->padded_average(),
tamao@5120 392 _avg_major_pause->padded_average(),
tamao@5120 393 _avg_minor_interval->average(),
tamao@5120 394 _avg_major_interval->average(),
tamao@5120 395 gc_pause_goal_sec());
tamao@5120 396 }
tamao@5120 397
tamao@5120 398 // Footprint stats
tamao@5120 399 gclog_or_tty->print( " live_space: " SIZE_FORMAT
tamao@5120 400 " free_space: " SIZE_FORMAT,
tamao@5120 401 live_space(), free_space());
tamao@5120 402 // More detail
tamao@5120 403 if (Verbose) {
tamao@5120 404 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
tamao@5120 405 " avg_young_live: " SIZE_FORMAT
tamao@5120 406 " avg_old_live: " SIZE_FORMAT,
tamao@5120 407 (size_t)_avg_base_footprint->average(),
tamao@5120 408 (size_t)avg_young_live()->average(),
tamao@5120 409 (size_t)avg_old_live()->average());
tamao@5120 410 }
tamao@5120 411
tamao@5120 412 // And finally, our old and new sizes.
tamao@5120 413 gclog_or_tty->print(" old_eden_size: " SIZE_FORMAT
tamao@5120 414 " desired_eden_size: " SIZE_FORMAT,
tamao@5120 415 _eden_size, desired_eden_size);
tamao@5120 416 gclog_or_tty->cr();
tamao@5120 417 }
tamao@5120 418
tamao@5120 419 set_eden_size(desired_eden_size);
tamao@5120 420 }
tamao@5120 421
tamao@5120 422 void PSAdaptiveSizePolicy::compute_old_gen_free_space(
tamao@5120 423 size_t old_live,
tamao@5120 424 size_t cur_eden,
tamao@5120 425 size_t max_old_gen_size,
tamao@5120 426 bool is_full_gc) {
tamao@5120 427
tamao@5120 428 // Update statistics
tamao@5120 429 // Time statistics are updated as we go, update footprint stats here
duke@435 430 if (is_full_gc) {
duke@435 431 // old_live is only accurate after a full gc
duke@435 432 avg_old_live()->sample(old_live);
duke@435 433 }
duke@435 434
duke@435 435 // This code used to return if the policy was not ready , i.e.,
duke@435 436 // policy_is_ready() returning false. The intent was that
duke@435 437 // decisions below needed major collection times and so could
duke@435 438 // not be made before two major collections. A consequence was
duke@435 439 // adjustments to the young generation were not done until after
duke@435 440 // two major collections even if the minor collections times
duke@435 441 // exceeded the requested goals. Now let the young generation
duke@435 442 // adjust for the minor collection times. Major collection times
duke@435 443 // will be zero for the first collection and will naturally be
duke@435 444 // ignored. Tenured generation adjustments are only made at the
duke@435 445 // full collections so until the second major collection has
duke@435 446 // been reached, no tenured generation adjustments will be made.
duke@435 447
duke@435 448 // Until we know better, desired promotion size uses the last calculation
duke@435 449 size_t desired_promo_size = _promo_size;
duke@435 450
duke@435 451 // Start eden at the current value. The desired value that is stored
duke@435 452 // in _eden_size is not bounded by constraints of the heap and can
duke@435 453 // run away.
duke@435 454 //
duke@435 455 // As expected setting desired_eden_size to the current
duke@435 456 // value of desired_eden_size as a starting point
duke@435 457 // caused desired_eden_size to grow way too large and caused
duke@435 458 // an overflow down stream. It may have improved performance in
duke@435 459 // some case but is dangerous.
duke@435 460 size_t desired_eden_size = cur_eden;
duke@435 461
duke@435 462 // Cache some values. There's a bit of work getting these, so
duke@435 463 // we might save a little time.
duke@435 464 const double major_cost = major_gc_cost();
duke@435 465 const double minor_cost = minor_gc_cost();
duke@435 466
duke@435 467 // Limits on our growth
duke@435 468 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
duke@435 469
duke@435 470 // But don't force a promo size below the current promo size. Otherwise,
duke@435 471 // the promo size will shrink for no good reason.
duke@435 472 promo_limit = MAX2(promo_limit, _promo_size);
duke@435 473
duke@435 474 const double gc_cost_limit = GCTimeLimit/100.0;
duke@435 475
duke@435 476 // Which way should we go?
duke@435 477 // if pause requirement is not met
duke@435 478 // adjust size of any generation with average paus exceeding
duke@435 479 // the pause limit. Adjust one pause at a time (the larger)
duke@435 480 // and only make adjustments for the major pause at full collections.
duke@435 481 // else if throughput requirement not met
duke@435 482 // adjust the size of the generation with larger gc time. Only
duke@435 483 // adjust one generation at a time.
duke@435 484 // else
duke@435 485 // adjust down the total heap size. Adjust down the larger of the
duke@435 486 // generations.
duke@435 487
duke@435 488 // Add some checks for a threshhold for a change. For example,
duke@435 489 // a change less than the necessary alignment is probably not worth
duke@435 490 // attempting.
duke@435 491
duke@435 492 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
duke@435 493 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
duke@435 494 //
duke@435 495 // Check pauses
duke@435 496 //
duke@435 497 // Make changes only to affect one of the pauses (the larger)
duke@435 498 // at a time.
tamao@5120 499 if (is_full_gc) {
tamao@5120 500 set_decide_at_full_gc(decide_at_full_gc_true);
tamao@5120 501 adjust_promo_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
tamao@5120 502 }
duke@435 503 } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
duke@435 504 // Adjust only for the minor pause time goal
tamao@5120 505 adjust_promo_for_minor_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
duke@435 506 } else if(adjusted_mutator_cost() < _throughput_goal) {
duke@435 507 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
duke@435 508 // This sometimes resulted in skipping to the minimize footprint
duke@435 509 // code. Change this to try and reduce GC time if mutator time is
duke@435 510 // negative for whatever reason. Or for future consideration,
duke@435 511 // bail out of the code if mutator time is negative.
duke@435 512 //
duke@435 513 // Throughput
duke@435 514 //
duke@435 515 assert(major_cost >= 0.0, "major cost is < 0.0");
duke@435 516 assert(minor_cost >= 0.0, "minor cost is < 0.0");
duke@435 517 // Try to reduce the GC times.
tamao@5120 518 if (is_full_gc) {
tamao@5120 519 set_decide_at_full_gc(decide_at_full_gc_true);
tamao@5120 520 adjust_promo_for_throughput(is_full_gc, &desired_promo_size);
tamao@5120 521 }
duke@435 522 } else {
duke@435 523
duke@435 524 // Be conservative about reducing the footprint.
duke@435 525 // Do a minimum number of major collections first.
duke@435 526 // Have reasonable averages for major and minor collections costs.
duke@435 527 if (UseAdaptiveSizePolicyFootprintGoal &&
duke@435 528 young_gen_policy_is_ready() &&
duke@435 529 avg_major_gc_cost()->average() >= 0.0 &&
duke@435 530 avg_minor_gc_cost()->average() >= 0.0) {
duke@435 531 if (is_full_gc) {
duke@435 532 set_decide_at_full_gc(decide_at_full_gc_true);
tamao@5120 533 size_t desired_sum = desired_eden_size + desired_promo_size;
tamao@5120 534 desired_promo_size = adjust_promo_for_footprint(desired_promo_size, desired_sum);
duke@435 535 }
duke@435 536 }
duke@435 537 }
duke@435 538
duke@435 539 // Note we make the same tests as in the code block below; the code
duke@435 540 // seems a little easier to read with the printing in another block.
duke@435 541 if (PrintAdaptiveSizePolicy) {
duke@435 542 if (desired_promo_size > promo_limit) {
duke@435 543 // "free_in_old_gen" was the original value for used for promo_limit
duke@435 544 size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
duke@435 545 gclog_or_tty->print_cr(
tamao@5120 546 "PSAdaptiveSizePolicy::compute_old_gen_free_space limits:"
duke@435 547 " desired_promo_size: " SIZE_FORMAT
duke@435 548 " promo_limit: " SIZE_FORMAT
duke@435 549 " free_in_old_gen: " SIZE_FORMAT
duke@435 550 " max_old_gen_size: " SIZE_FORMAT
duke@435 551 " avg_old_live: " SIZE_FORMAT,
duke@435 552 desired_promo_size, promo_limit, free_in_old_gen,
duke@435 553 max_old_gen_size, (size_t) avg_old_live()->average());
duke@435 554 }
duke@435 555 if (gc_cost() > gc_cost_limit) {
duke@435 556 gclog_or_tty->print_cr(
tamao@5120 557 "PSAdaptiveSizePolicy::compute_old_gen_free_space: gc time limit"
duke@435 558 " gc_cost: %f "
duke@435 559 " GCTimeLimit: %d",
duke@435 560 gc_cost(), GCTimeLimit);
duke@435 561 }
duke@435 562 }
duke@435 563
duke@435 564 // Align everything and make a final limit check
duke@435 565 const size_t alignment = _intra_generation_alignment;
duke@435 566 desired_promo_size = align_size_up(desired_promo_size, alignment);
duke@435 567 desired_promo_size = MAX2(desired_promo_size, alignment);
duke@435 568
duke@435 569 promo_limit = align_size_down(promo_limit, alignment);
duke@435 570
duke@435 571 // And one last limit check, now that we've aligned things.
duke@435 572 desired_promo_size = MIN2(desired_promo_size, promo_limit);
duke@435 573
duke@435 574 if (PrintAdaptiveSizePolicy) {
duke@435 575 // Timing stats
duke@435 576 gclog_or_tty->print(
tamao@5120 577 "PSAdaptiveSizePolicy::compute_old_gen_free_space: costs"
duke@435 578 " minor_time: %f"
duke@435 579 " major_cost: %f"
duke@435 580 " mutator_cost: %f"
duke@435 581 " throughput_goal: %f",
duke@435 582 minor_gc_cost(), major_gc_cost(), mutator_cost(),
duke@435 583 _throughput_goal);
duke@435 584
duke@435 585 // We give more details if Verbose is set
duke@435 586 if (Verbose) {
duke@435 587 gclog_or_tty->print( " minor_pause: %f"
duke@435 588 " major_pause: %f"
duke@435 589 " minor_interval: %f"
duke@435 590 " major_interval: %f"
duke@435 591 " pause_goal: %f",
duke@435 592 _avg_minor_pause->padded_average(),
duke@435 593 _avg_major_pause->padded_average(),
duke@435 594 _avg_minor_interval->average(),
duke@435 595 _avg_major_interval->average(),
duke@435 596 gc_pause_goal_sec());
duke@435 597 }
duke@435 598
duke@435 599 // Footprint stats
duke@435 600 gclog_or_tty->print( " live_space: " SIZE_FORMAT
duke@435 601 " free_space: " SIZE_FORMAT,
duke@435 602 live_space(), free_space());
duke@435 603 // More detail
duke@435 604 if (Verbose) {
duke@435 605 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
duke@435 606 " avg_young_live: " SIZE_FORMAT
duke@435 607 " avg_old_live: " SIZE_FORMAT,
duke@435 608 (size_t)_avg_base_footprint->average(),
duke@435 609 (size_t)avg_young_live()->average(),
duke@435 610 (size_t)avg_old_live()->average());
duke@435 611 }
duke@435 612
duke@435 613 // And finally, our old and new sizes.
duke@435 614 gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT
tamao@5120 615 " desired_promo_size: " SIZE_FORMAT,
tamao@5120 616 _promo_size, desired_promo_size);
duke@435 617 gclog_or_tty->cr();
duke@435 618 }
duke@435 619
duke@435 620 set_promo_size(desired_promo_size);
tamao@5120 621 }
duke@435 622
duke@435 623 void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) {
duke@435 624 // Decay the supplemental increment? Decay the supplement growth
duke@435 625 // factor even if it is not used. It is only meant to give a boost
duke@435 626 // to the initial growth and if it is not used, then it was not
duke@435 627 // needed.
duke@435 628 if (is_full_gc) {
duke@435 629 // Don't wait for the threshold value for the major collections. If
duke@435 630 // here, the supplemental growth term was used and should decay.
duke@435 631 if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay)
duke@435 632 == 0) {
duke@435 633 _old_gen_size_increment_supplement =
duke@435 634 _old_gen_size_increment_supplement >> 1;
duke@435 635 }
duke@435 636 } else {
duke@435 637 if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) &&
duke@435 638 (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) {
duke@435 639 _young_gen_size_increment_supplement =
duke@435 640 _young_gen_size_increment_supplement >> 1;
duke@435 641 }
duke@435 642 }
duke@435 643 }
duke@435 644
tamao@5120 645 void PSAdaptiveSizePolicy::adjust_promo_for_minor_pause_time(bool is_full_gc,
duke@435 646 size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) {
duke@435 647
tamao@5120 648 if (PSAdjustTenuredGenForMinorPause) {
tamao@5120 649 if (is_full_gc) {
tamao@5120 650 set_decide_at_full_gc(decide_at_full_gc_true);
tamao@5120 651 }
tamao@5120 652 // If the desired eden size is as small as it will get,
tamao@5120 653 // try to adjust the old gen size.
tamao@5120 654 if (*desired_eden_size_ptr <= _intra_generation_alignment) {
tamao@5120 655 // Vary the old gen size to reduce the young gen pause. This
tamao@5120 656 // may not be a good idea. This is just a test.
tamao@5120 657 if (minor_pause_old_estimator()->decrement_will_decrease()) {
tamao@5120 658 set_change_old_gen_for_min_pauses(decrease_old_gen_for_min_pauses_true);
tamao@5120 659 *desired_promo_size_ptr =
tamao@5120 660 _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr);
tamao@5120 661 } else {
tamao@5120 662 set_change_old_gen_for_min_pauses(increase_old_gen_for_min_pauses_true);
tamao@5120 663 size_t promo_heap_delta =
tamao@5120 664 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
tamao@5120 665 if ((*desired_promo_size_ptr + promo_heap_delta) >
tamao@5120 666 *desired_promo_size_ptr) {
tamao@5120 667 *desired_promo_size_ptr =
tamao@5120 668 _promo_size + promo_heap_delta;
tamao@5120 669 }
tamao@5120 670 }
tamao@5120 671 }
tamao@5120 672 }
tamao@5120 673 }
tamao@5120 674
tamao@5120 675 void PSAdaptiveSizePolicy::adjust_eden_for_minor_pause_time(bool is_full_gc,
tamao@5120 676 size_t* desired_eden_size_ptr) {
tamao@5120 677
duke@435 678 // Adjust the young generation size to reduce pause time of
duke@435 679 // of collections.
duke@435 680 //
duke@435 681 // The AdaptiveSizePolicyInitializingSteps test is not used
duke@435 682 // here. It has not seemed to be needed but perhaps should
duke@435 683 // be added for consistency.
duke@435 684 if (minor_pause_young_estimator()->decrement_will_decrease()) {
duke@435 685 // reduce eden size
duke@435 686 set_change_young_gen_for_min_pauses(
duke@435 687 decrease_young_gen_for_min_pauses_true);
duke@435 688 *desired_eden_size_ptr = *desired_eden_size_ptr -
duke@435 689 eden_decrement_aligned_down(*desired_eden_size_ptr);
duke@435 690 } else {
duke@435 691 // EXPERIMENTAL ADJUSTMENT
duke@435 692 // Only record that the estimator indicated such an action.
duke@435 693 // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta;
duke@435 694 set_change_young_gen_for_min_pauses(
duke@435 695 increase_young_gen_for_min_pauses_true);
duke@435 696 }
duke@435 697 }
duke@435 698
tamao@5120 699 void PSAdaptiveSizePolicy::adjust_promo_for_pause_time(bool is_full_gc,
duke@435 700 size_t* desired_promo_size_ptr,
duke@435 701 size_t* desired_eden_size_ptr) {
duke@435 702
duke@435 703 size_t promo_heap_delta = 0;
tamao@5120 704 // Add some checks for a threshold for a change. For example,
duke@435 705 // a change less than the required alignment is probably not worth
duke@435 706 // attempting.
duke@435 707
duke@435 708 if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
tamao@5120 709 adjust_promo_for_minor_pause_time(is_full_gc, desired_promo_size_ptr, desired_eden_size_ptr);
duke@435 710 // major pause adjustments
duke@435 711 } else if (is_full_gc) {
duke@435 712 // Adjust for the major pause time only at full gc's because the
duke@435 713 // affects of a change can only be seen at full gc's.
duke@435 714
duke@435 715 // Reduce old generation size to reduce pause?
duke@435 716 if (major_pause_old_estimator()->decrement_will_decrease()) {
duke@435 717 // reduce old generation size
duke@435 718 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
duke@435 719 promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr);
duke@435 720 *desired_promo_size_ptr = _promo_size - promo_heap_delta;
duke@435 721 } else {
duke@435 722 // EXPERIMENTAL ADJUSTMENT
duke@435 723 // Only record that the estimator indicated such an action.
duke@435 724 // *desired_promo_size_ptr = _promo_size +
duke@435 725 // promo_increment_aligned_up(*desired_promo_size_ptr);
duke@435 726 set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true);
duke@435 727 }
tamao@5120 728 }
tamao@5120 729
tamao@5120 730 if (PrintAdaptiveSizePolicy && Verbose) {
tamao@5120 731 gclog_or_tty->print_cr(
tamao@5192 732 "PSAdaptiveSizePolicy::adjust_promo_for_pause_time "
tamao@5120 733 "adjusting gen sizes for major pause (avg %f goal %f). "
tamao@5120 734 "desired_promo_size " SIZE_FORMAT " promo delta " SIZE_FORMAT,
tamao@5120 735 _avg_major_pause->average(), gc_pause_goal_sec(),
tamao@5120 736 *desired_promo_size_ptr, promo_heap_delta);
tamao@5120 737 }
tamao@5120 738 }
tamao@5120 739
tamao@5120 740 void PSAdaptiveSizePolicy::adjust_eden_for_pause_time(bool is_full_gc,
tamao@5120 741 size_t* desired_promo_size_ptr,
tamao@5120 742 size_t* desired_eden_size_ptr) {
tamao@5120 743
tamao@5120 744 size_t eden_heap_delta = 0;
tamao@5120 745 // Add some checks for a threshold for a change. For example,
tamao@5120 746 // a change less than the required alignment is probably not worth
tamao@5120 747 // attempting.
tamao@5120 748 if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
tamao@5120 749 adjust_eden_for_minor_pause_time(is_full_gc,
tamao@5120 750 desired_eden_size_ptr);
tamao@5120 751 // major pause adjustments
tamao@5120 752 } else if (is_full_gc) {
tamao@5120 753 // Adjust for the major pause time only at full gc's because the
tamao@5120 754 // affects of a change can only be seen at full gc's.
duke@435 755 if (PSAdjustYoungGenForMajorPause) {
duke@435 756 // If the promo size is at the minimum (i.e., the old gen
duke@435 757 // size will not actually decrease), consider changing the
duke@435 758 // young gen size.
duke@435 759 if (*desired_promo_size_ptr < _intra_generation_alignment) {
duke@435 760 // If increasing the young generation will decrease the old gen
duke@435 761 // pause, do it.
duke@435 762 // During startup there is noise in the statistics for deciding
duke@435 763 // on whether to increase or decrease the young gen size. For
duke@435 764 // some number of iterations, just try to increase the young
duke@435 765 // gen size if the major pause is too long to try and establish
duke@435 766 // good statistics for later decisions.
duke@435 767 if (major_pause_young_estimator()->increment_will_decrease() ||
duke@435 768 (_young_gen_change_for_major_pause_count
duke@435 769 <= AdaptiveSizePolicyInitializingSteps)) {
duke@435 770 set_change_young_gen_for_maj_pauses(
duke@435 771 increase_young_gen_for_maj_pauses_true);
duke@435 772 eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr);
duke@435 773 *desired_eden_size_ptr = _eden_size + eden_heap_delta;
duke@435 774 _young_gen_change_for_major_pause_count++;
duke@435 775 } else {
duke@435 776 // Record that decreasing the young gen size would decrease
duke@435 777 // the major pause
duke@435 778 set_change_young_gen_for_maj_pauses(
duke@435 779 decrease_young_gen_for_maj_pauses_true);
duke@435 780 eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr);
duke@435 781 *desired_eden_size_ptr = _eden_size - eden_heap_delta;
duke@435 782 }
duke@435 783 }
duke@435 784 }
duke@435 785 }
duke@435 786
duke@435 787 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 788 gclog_or_tty->print_cr(
tamao@5192 789 "PSAdaptiveSizePolicy::adjust_eden_for_pause_time "
duke@435 790 "adjusting gen sizes for major pause (avg %f goal %f). "
tamao@5120 791 "desired_eden_size " SIZE_FORMAT " eden delta " SIZE_FORMAT,
duke@435 792 _avg_major_pause->average(), gc_pause_goal_sec(),
tamao@5120 793 *desired_eden_size_ptr, eden_heap_delta);
duke@435 794 }
duke@435 795 }
duke@435 796
tamao@5120 797 void PSAdaptiveSizePolicy::adjust_promo_for_throughput(bool is_full_gc,
tamao@5120 798 size_t* desired_promo_size_ptr) {
duke@435 799
tamao@5120 800 // Add some checks for a threshold for a change. For example,
duke@435 801 // a change less than the required alignment is probably not worth
duke@435 802 // attempting.
duke@435 803
duke@435 804 if ((gc_cost() + mutator_cost()) == 0.0) {
duke@435 805 return;
duke@435 806 }
duke@435 807
duke@435 808 if (PrintAdaptiveSizePolicy && Verbose) {
tamao@5120 809 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_promo_for_throughput("
tamao@5120 810 "is_full: %d, promo: " SIZE_FORMAT "): ",
tamao@5120 811 is_full_gc, *desired_promo_size_ptr);
duke@435 812 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
duke@435 813 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
duke@435 814 }
duke@435 815
duke@435 816 // Tenured generation
duke@435 817 if (is_full_gc) {
duke@435 818 // Calculate the change to use for the tenured gen.
duke@435 819 size_t scaled_promo_heap_delta = 0;
duke@435 820 // Can the increment to the generation be scaled?
duke@435 821 if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) {
duke@435 822 size_t promo_heap_delta =
duke@435 823 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
duke@435 824 double scale_by_ratio = major_gc_cost() / gc_cost();
duke@435 825 scaled_promo_heap_delta =
duke@435 826 (size_t) (scale_by_ratio * (double) promo_heap_delta);
duke@435 827 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 828 gclog_or_tty->print_cr(
duke@435 829 "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
duke@435 830 SIZE_FORMAT,
duke@435 831 promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta);
duke@435 832 }
duke@435 833 } else if (major_gc_cost() >= 0.0) {
duke@435 834 // Scaling is not going to work. If the major gc time is the
duke@435 835 // larger, give it a full increment.
duke@435 836 if (major_gc_cost() >= minor_gc_cost()) {
duke@435 837 scaled_promo_heap_delta =
duke@435 838 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
duke@435 839 }
duke@435 840 } else {
duke@435 841 // Don't expect to get here but it's ok if it does
duke@435 842 // in the product build since the delta will be 0
duke@435 843 // and nothing will change.
duke@435 844 assert(false, "Unexpected value for gc costs");
duke@435 845 }
duke@435 846
duke@435 847 switch (AdaptiveSizeThroughPutPolicy) {
duke@435 848 case 1:
duke@435 849 // Early in the run the statistics might not be good. Until
duke@435 850 // a specific number of collections have been, use the heuristic
duke@435 851 // that a larger generation size means lower collection costs.
duke@435 852 if (major_collection_estimator()->increment_will_decrease() ||
duke@435 853 (_old_gen_change_for_major_throughput
duke@435 854 <= AdaptiveSizePolicyInitializingSteps)) {
duke@435 855 // Increase tenured generation size to reduce major collection cost
duke@435 856 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
duke@435 857 *desired_promo_size_ptr) {
duke@435 858 *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta;
duke@435 859 }
duke@435 860 set_change_old_gen_for_throughput(
duke@435 861 increase_old_gen_for_throughput_true);
duke@435 862 _old_gen_change_for_major_throughput++;
duke@435 863 } else {
duke@435 864 // EXPERIMENTAL ADJUSTMENT
duke@435 865 // Record that decreasing the old gen size would decrease
duke@435 866 // the major collection cost but don't do it.
duke@435 867 // *desired_promo_size_ptr = _promo_size -
duke@435 868 // promo_decrement_aligned_down(*desired_promo_size_ptr);
duke@435 869 set_change_old_gen_for_throughput(
duke@435 870 decrease_old_gen_for_throughput_true);
duke@435 871 }
duke@435 872
duke@435 873 break;
duke@435 874 default:
duke@435 875 // Simplest strategy
duke@435 876 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
duke@435 877 *desired_promo_size_ptr) {
duke@435 878 *desired_promo_size_ptr = *desired_promo_size_ptr +
duke@435 879 scaled_promo_heap_delta;
duke@435 880 }
duke@435 881 set_change_old_gen_for_throughput(
duke@435 882 increase_old_gen_for_throughput_true);
duke@435 883 _old_gen_change_for_major_throughput++;
duke@435 884 }
duke@435 885
duke@435 886 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 887 gclog_or_tty->print_cr(
duke@435 888 "adjusting tenured gen for throughput (avg %f goal %f). "
duke@435 889 "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT ,
duke@435 890 mutator_cost(), _throughput_goal,
duke@435 891 *desired_promo_size_ptr, scaled_promo_heap_delta);
duke@435 892 }
duke@435 893 }
tamao@5120 894 }
tamao@5120 895
tamao@5120 896 void PSAdaptiveSizePolicy::adjust_eden_for_throughput(bool is_full_gc,
tamao@5120 897 size_t* desired_eden_size_ptr) {
tamao@5120 898
tamao@5120 899 // Add some checks for a threshold for a change. For example,
tamao@5120 900 // a change less than the required alignment is probably not worth
tamao@5120 901 // attempting.
tamao@5120 902
tamao@5120 903 if ((gc_cost() + mutator_cost()) == 0.0) {
tamao@5120 904 return;
tamao@5120 905 }
tamao@5120 906
tamao@5120 907 if (PrintAdaptiveSizePolicy && Verbose) {
tamao@5120 908 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_eden_for_throughput("
tamao@5120 909 "is_full: %d, cur_eden: " SIZE_FORMAT "): ",
tamao@5120 910 is_full_gc, *desired_eden_size_ptr);
tamao@5120 911 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
tamao@5120 912 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
tamao@5120 913 }
duke@435 914
duke@435 915 // Young generation
duke@435 916 size_t scaled_eden_heap_delta = 0;
duke@435 917 // Can the increment to the generation be scaled?
duke@435 918 if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) {
duke@435 919 size_t eden_heap_delta =
duke@435 920 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
duke@435 921 double scale_by_ratio = minor_gc_cost() / gc_cost();
duke@435 922 assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong");
duke@435 923 scaled_eden_heap_delta =
duke@435 924 (size_t) (scale_by_ratio * (double) eden_heap_delta);
duke@435 925 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 926 gclog_or_tty->print_cr(
duke@435 927 "Scaled eden increment: " SIZE_FORMAT " by %f down to "
duke@435 928 SIZE_FORMAT,
duke@435 929 eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta);
duke@435 930 }
duke@435 931 } else if (minor_gc_cost() >= 0.0) {
duke@435 932 // Scaling is not going to work. If the minor gc time is the
duke@435 933 // larger, give it a full increment.
duke@435 934 if (minor_gc_cost() > major_gc_cost()) {
duke@435 935 scaled_eden_heap_delta =
duke@435 936 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
duke@435 937 }
duke@435 938 } else {
duke@435 939 // Don't expect to get here but it's ok if it does
duke@435 940 // in the product build since the delta will be 0
duke@435 941 // and nothing will change.
duke@435 942 assert(false, "Unexpected value for gc costs");
duke@435 943 }
duke@435 944
duke@435 945 // Use a heuristic for some number of collections to give
duke@435 946 // the averages time to settle down.
duke@435 947 switch (AdaptiveSizeThroughPutPolicy) {
duke@435 948 case 1:
duke@435 949 if (minor_collection_estimator()->increment_will_decrease() ||
duke@435 950 (_young_gen_change_for_minor_throughput
duke@435 951 <= AdaptiveSizePolicyInitializingSteps)) {
duke@435 952 // Expand young generation size to reduce frequency of
duke@435 953 // of collections.
duke@435 954 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
duke@435 955 *desired_eden_size_ptr) {
duke@435 956 *desired_eden_size_ptr =
duke@435 957 *desired_eden_size_ptr + scaled_eden_heap_delta;
duke@435 958 }
duke@435 959 set_change_young_gen_for_throughput(
duke@435 960 increase_young_gen_for_througput_true);
duke@435 961 _young_gen_change_for_minor_throughput++;
duke@435 962 } else {
duke@435 963 // EXPERIMENTAL ADJUSTMENT
duke@435 964 // Record that decreasing the young gen size would decrease
duke@435 965 // the minor collection cost but don't do it.
duke@435 966 // *desired_eden_size_ptr = _eden_size -
duke@435 967 // eden_decrement_aligned_down(*desired_eden_size_ptr);
duke@435 968 set_change_young_gen_for_throughput(
duke@435 969 decrease_young_gen_for_througput_true);
duke@435 970 }
duke@435 971 break;
duke@435 972 default:
duke@435 973 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
duke@435 974 *desired_eden_size_ptr) {
duke@435 975 *desired_eden_size_ptr =
duke@435 976 *desired_eden_size_ptr + scaled_eden_heap_delta;
duke@435 977 }
duke@435 978 set_change_young_gen_for_throughput(
duke@435 979 increase_young_gen_for_througput_true);
duke@435 980 _young_gen_change_for_minor_throughput++;
duke@435 981 }
duke@435 982
duke@435 983 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 984 gclog_or_tty->print_cr(
duke@435 985 "adjusting eden for throughput (avg %f goal %f). desired_eden_size "
duke@435 986 SIZE_FORMAT " eden delta " SIZE_FORMAT "\n",
duke@435 987 mutator_cost(), _throughput_goal,
duke@435 988 *desired_eden_size_ptr, scaled_eden_heap_delta);
duke@435 989 }
duke@435 990 }
duke@435 991
duke@435 992 size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint(
duke@435 993 size_t desired_promo_size, size_t desired_sum) {
duke@435 994 assert(desired_promo_size <= desired_sum, "Inconsistent parameters");
duke@435 995 set_decrease_for_footprint(decrease_old_gen_for_footprint_true);
duke@435 996
duke@435 997 size_t change = promo_decrement(desired_promo_size);
duke@435 998 change = scale_down(change, desired_promo_size, desired_sum);
duke@435 999
duke@435 1000 size_t reduced_size = desired_promo_size - change;
duke@435 1001
duke@435 1002 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 1003 gclog_or_tty->print_cr(
tamao@5192 1004 "AdaptiveSizePolicy::adjust_promo_for_footprint "
duke@435 1005 "adjusting tenured gen for footprint. "
duke@435 1006 "starting promo size " SIZE_FORMAT
duke@435 1007 " reduced promo size " SIZE_FORMAT,
duke@435 1008 " promo delta " SIZE_FORMAT,
duke@435 1009 desired_promo_size, reduced_size, change );
duke@435 1010 }
duke@435 1011
duke@435 1012 assert(reduced_size <= desired_promo_size, "Inconsistent result");
duke@435 1013 return reduced_size;
duke@435 1014 }
duke@435 1015
duke@435 1016 size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint(
duke@435 1017 size_t desired_eden_size, size_t desired_sum) {
duke@435 1018 assert(desired_eden_size <= desired_sum, "Inconsistent parameters");
duke@435 1019 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
duke@435 1020
duke@435 1021 size_t change = eden_decrement(desired_eden_size);
duke@435 1022 change = scale_down(change, desired_eden_size, desired_sum);
duke@435 1023
duke@435 1024 size_t reduced_size = desired_eden_size - change;
duke@435 1025
duke@435 1026 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 1027 gclog_or_tty->print_cr(
tamao@5192 1028 "AdaptiveSizePolicy::adjust_eden_for_footprint "
duke@435 1029 "adjusting eden for footprint. "
duke@435 1030 " starting eden size " SIZE_FORMAT
duke@435 1031 " reduced eden size " SIZE_FORMAT
duke@435 1032 " eden delta " SIZE_FORMAT,
duke@435 1033 desired_eden_size, reduced_size, change);
duke@435 1034 }
duke@435 1035
duke@435 1036 assert(reduced_size <= desired_eden_size, "Inconsistent result");
duke@435 1037 return reduced_size;
duke@435 1038 }
duke@435 1039
duke@435 1040 // Scale down "change" by the factor
duke@435 1041 // part / total
duke@435 1042 // Don't align the results.
duke@435 1043
duke@435 1044 size_t PSAdaptiveSizePolicy::scale_down(size_t change,
duke@435 1045 double part,
duke@435 1046 double total) {
duke@435 1047 assert(part <= total, "Inconsistent input");
duke@435 1048 size_t reduced_change = change;
duke@435 1049 if (total > 0) {
duke@435 1050 double fraction = part / total;
duke@435 1051 reduced_change = (size_t) (fraction * (double) change);
duke@435 1052 }
duke@435 1053 assert(reduced_change <= change, "Inconsistent result");
duke@435 1054 return reduced_change;
duke@435 1055 }
duke@435 1056
duke@435 1057 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden,
duke@435 1058 uint percent_change) {
duke@435 1059 size_t eden_heap_delta;
duke@435 1060 eden_heap_delta = cur_eden / 100 * percent_change;
duke@435 1061 return eden_heap_delta;
duke@435 1062 }
duke@435 1063
duke@435 1064 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) {
duke@435 1065 return eden_increment(cur_eden, YoungGenerationSizeIncrement);
duke@435 1066 }
duke@435 1067
duke@435 1068 size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
duke@435 1069 size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement);
duke@435 1070 return align_size_up(result, _intra_generation_alignment);
duke@435 1071 }
duke@435 1072
duke@435 1073 size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) {
duke@435 1074 size_t result = eden_increment(cur_eden);
duke@435 1075 return align_size_down(result, _intra_generation_alignment);
duke@435 1076 }
duke@435 1077
duke@435 1078 size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up(
duke@435 1079 size_t cur_eden) {
duke@435 1080 size_t result = eden_increment(cur_eden,
duke@435 1081 YoungGenerationSizeIncrement + _young_gen_size_increment_supplement);
duke@435 1082 return align_size_up(result, _intra_generation_alignment);
duke@435 1083 }
duke@435 1084
duke@435 1085 size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
duke@435 1086 size_t eden_heap_delta = eden_decrement(cur_eden);
duke@435 1087 return align_size_down(eden_heap_delta, _intra_generation_alignment);
duke@435 1088 }
duke@435 1089
duke@435 1090 size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
duke@435 1091 size_t eden_heap_delta = eden_increment(cur_eden) /
duke@435 1092 AdaptiveSizeDecrementScaleFactor;
duke@435 1093 return eden_heap_delta;
duke@435 1094 }
duke@435 1095
duke@435 1096 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo,
duke@435 1097 uint percent_change) {
duke@435 1098 size_t promo_heap_delta;
duke@435 1099 promo_heap_delta = cur_promo / 100 * percent_change;
duke@435 1100 return promo_heap_delta;
duke@435 1101 }
duke@435 1102
duke@435 1103 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) {
duke@435 1104 return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
duke@435 1105 }
duke@435 1106
duke@435 1107 size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
duke@435 1108 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
duke@435 1109 return align_size_up(result, _intra_generation_alignment);
duke@435 1110 }
duke@435 1111
duke@435 1112 size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) {
duke@435 1113 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
duke@435 1114 return align_size_down(result, _intra_generation_alignment);
duke@435 1115 }
duke@435 1116
duke@435 1117 size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up(
duke@435 1118 size_t cur_promo) {
duke@435 1119 size_t result = promo_increment(cur_promo,
duke@435 1120 TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement);
duke@435 1121 return align_size_up(result, _intra_generation_alignment);
duke@435 1122 }
duke@435 1123
duke@435 1124 size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
duke@435 1125 size_t promo_heap_delta = promo_decrement(cur_promo);
duke@435 1126 return align_size_down(promo_heap_delta, _intra_generation_alignment);
duke@435 1127 }
duke@435 1128
duke@435 1129 size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
duke@435 1130 size_t promo_heap_delta = promo_increment(cur_promo);
duke@435 1131 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
duke@435 1132 return promo_heap_delta;
duke@435 1133 }
duke@435 1134
jwilhelm@4129 1135 uint PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
duke@435 1136 bool is_survivor_overflow,
jwilhelm@4129 1137 uint tenuring_threshold,
duke@435 1138 size_t survivor_limit) {
duke@435 1139 assert(survivor_limit >= _intra_generation_alignment,
duke@435 1140 "survivor_limit too small");
duke@435 1141 assert((size_t)align_size_down(survivor_limit, _intra_generation_alignment)
duke@435 1142 == survivor_limit, "survivor_limit not aligned");
duke@435 1143
duke@435 1144 // This method is called even if the tenuring threshold and survivor
duke@435 1145 // spaces are not adjusted so that the averages are sampled above.
duke@435 1146 if (!UsePSAdaptiveSurvivorSizePolicy ||
duke@435 1147 !young_gen_policy_is_ready()) {
duke@435 1148 return tenuring_threshold;
duke@435 1149 }
duke@435 1150
duke@435 1151 // We'll decide whether to increase or decrease the tenuring
duke@435 1152 // threshold based partly on the newly computed survivor size
duke@435 1153 // (if we hit the maximum limit allowed, we'll always choose to
duke@435 1154 // decrement the threshold).
duke@435 1155 bool incr_tenuring_threshold = false;
duke@435 1156 bool decr_tenuring_threshold = false;
duke@435 1157
duke@435 1158 set_decrement_tenuring_threshold_for_gc_cost(false);
duke@435 1159 set_increment_tenuring_threshold_for_gc_cost(false);
duke@435 1160 set_decrement_tenuring_threshold_for_survivor_limit(false);
duke@435 1161
duke@435 1162 if (!is_survivor_overflow) {
duke@435 1163 // Keep running averages on how much survived
duke@435 1164
duke@435 1165 // We use the tenuring threshold to equalize the cost of major
duke@435 1166 // and minor collections.
duke@435 1167 // ThresholdTolerance is used to indicate how sensitive the
duke@435 1168 // tenuring threshold is to differences in cost betweent the
duke@435 1169 // collection types.
duke@435 1170
duke@435 1171 // Get the times of interest. This involves a little work, so
duke@435 1172 // we cache the values here.
duke@435 1173 const double major_cost = major_gc_cost();
duke@435 1174 const double minor_cost = minor_gc_cost();
duke@435 1175
duke@435 1176 if (minor_cost > major_cost * _threshold_tolerance_percent) {
duke@435 1177 // Minor times are getting too long; lower the threshold so
duke@435 1178 // less survives and more is promoted.
duke@435 1179 decr_tenuring_threshold = true;
duke@435 1180 set_decrement_tenuring_threshold_for_gc_cost(true);
duke@435 1181 } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
duke@435 1182 // Major times are too long, so we want less promotion.
duke@435 1183 incr_tenuring_threshold = true;
duke@435 1184 set_increment_tenuring_threshold_for_gc_cost(true);
duke@435 1185 }
duke@435 1186
duke@435 1187 } else {
duke@435 1188 // Survivor space overflow occurred, so promoted and survived are
duke@435 1189 // not accurate. We'll make our best guess by combining survived
duke@435 1190 // and promoted and count them as survivors.
duke@435 1191 //
duke@435 1192 // We'll lower the tenuring threshold to see if we can correct
duke@435 1193 // things. Also, set the survivor size conservatively. We're
duke@435 1194 // trying to avoid many overflows from occurring if defnew size
duke@435 1195 // is just too small.
duke@435 1196
duke@435 1197 decr_tenuring_threshold = true;
duke@435 1198 }
duke@435 1199
duke@435 1200 // The padded average also maintains a deviation from the average;
duke@435 1201 // we use this to see how good of an estimate we have of what survived.
duke@435 1202 // We're trying to pad the survivor size as little as possible without
duke@435 1203 // overflowing the survivor spaces.
duke@435 1204 size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
duke@435 1205 _intra_generation_alignment);
duke@435 1206 target_size = MAX2(target_size, _intra_generation_alignment);
duke@435 1207
duke@435 1208 if (target_size > survivor_limit) {
duke@435 1209 // Target size is bigger than we can handle. Let's also reduce
duke@435 1210 // the tenuring threshold.
duke@435 1211 target_size = survivor_limit;
duke@435 1212 decr_tenuring_threshold = true;
duke@435 1213 set_decrement_tenuring_threshold_for_survivor_limit(true);
duke@435 1214 }
duke@435 1215
duke@435 1216 // Finally, increment or decrement the tenuring threshold, as decided above.
duke@435 1217 // We test for decrementing first, as we might have hit the target size
duke@435 1218 // limit.
duke@435 1219 if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
duke@435 1220 if (tenuring_threshold > 1) {
duke@435 1221 tenuring_threshold--;
duke@435 1222 }
duke@435 1223 } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
duke@435 1224 if (tenuring_threshold < MaxTenuringThreshold) {
duke@435 1225 tenuring_threshold++;
duke@435 1226 }
duke@435 1227 }
duke@435 1228
duke@435 1229 // We keep a running average of the amount promoted which is used
duke@435 1230 // to decide when we should collect the old generation (when
duke@435 1231 // the amount of old gen free space is less than what we expect to
duke@435 1232 // promote).
duke@435 1233
duke@435 1234 if (PrintAdaptiveSizePolicy) {
duke@435 1235 // A little more detail if Verbose is on
duke@435 1236 if (Verbose) {
duke@435 1237 gclog_or_tty->print( " avg_survived: %f"
duke@435 1238 " avg_deviation: %f",
duke@435 1239 _avg_survived->average(),
duke@435 1240 _avg_survived->deviation());
duke@435 1241 }
duke@435 1242
duke@435 1243 gclog_or_tty->print( " avg_survived_padded_avg: %f",
duke@435 1244 _avg_survived->padded_average());
duke@435 1245
duke@435 1246 if (Verbose) {
duke@435 1247 gclog_or_tty->print( " avg_promoted_avg: %f"
duke@435 1248 " avg_promoted_dev: %f",
duke@435 1249 avg_promoted()->average(),
duke@435 1250 avg_promoted()->deviation());
duke@435 1251 }
duke@435 1252
poonam@5279 1253 gclog_or_tty->print_cr( " avg_promoted_padded_avg: %f"
duke@435 1254 " avg_pretenured_padded_avg: %f"
duke@435 1255 " tenuring_thresh: %d"
duke@435 1256 " target_size: " SIZE_FORMAT,
duke@435 1257 avg_promoted()->padded_average(),
duke@435 1258 _avg_pretenured->padded_average(),
duke@435 1259 tenuring_threshold, target_size);
duke@435 1260 }
duke@435 1261
duke@435 1262 set_survivor_size(target_size);
duke@435 1263
duke@435 1264 return tenuring_threshold;
duke@435 1265 }
duke@435 1266
duke@435 1267 void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow,
duke@435 1268 size_t survived,
duke@435 1269 size_t promoted) {
duke@435 1270 // Update averages
duke@435 1271 if (!is_survivor_overflow) {
duke@435 1272 // Keep running averages on how much survived
duke@435 1273 _avg_survived->sample(survived);
duke@435 1274 } else {
duke@435 1275 size_t survived_guess = survived + promoted;
duke@435 1276 _avg_survived->sample(survived_guess);
duke@435 1277 }
duke@435 1278 avg_promoted()->sample(promoted + _avg_pretenured->padded_average());
duke@435 1279
duke@435 1280 if (PrintAdaptiveSizePolicy) {
poonam@5279 1281 gclog_or_tty->print_cr(
tamao@5192 1282 "AdaptiveSizePolicy::update_averages:"
duke@435 1283 " survived: " SIZE_FORMAT
duke@435 1284 " promoted: " SIZE_FORMAT
duke@435 1285 " overflow: %s",
duke@435 1286 survived, promoted, is_survivor_overflow ? "true" : "false");
duke@435 1287 }
duke@435 1288 }
duke@435 1289
duke@435 1290 bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st)
duke@435 1291 const {
duke@435 1292
duke@435 1293 if (!UseAdaptiveSizePolicy) return false;
duke@435 1294
duke@435 1295 return AdaptiveSizePolicy::print_adaptive_size_policy_on(
duke@435 1296 st,
duke@435 1297 PSScavenge::tenuring_threshold());
duke@435 1298 }

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