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

Fri, 01 Nov 2013 17:09:38 +0100

author
jwilhelm
date
Fri, 01 Nov 2013 17:09:38 +0100
changeset 6085
8f07aa079343
parent 6084
46d7652b223c
child 6267
a034dc5e910b
permissions
-rw-r--r--

8016309: assert(eden_size > 0 && survivor_size > 0) failed: just checking
7057939: jmap shows MaxNewSize=4GB when Java is using parallel collector
Summary: Major cleanup of the collectorpolicy classes
Reviewed-by: tschatzl, jcoomes

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/psAdaptiveSizePolicy.hpp"
stefank@2314 27 #include "gc_implementation/parallelScavenge/psGCAdaptivePolicyCounters.hpp"
stefank@2314 28 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
stefank@2314 29 #include "gc_implementation/shared/gcPolicyCounters.hpp"
stefank@2314 30 #include "gc_interface/gcCause.hpp"
stefank@2314 31 #include "memory/collectorPolicy.hpp"
stefank@2314 32 #include "runtime/timer.hpp"
stefank@2314 33 #include "utilities/top.hpp"
duke@435 34
duke@435 35 #include <math.h>
duke@435 36
duke@435 37 PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size,
duke@435 38 size_t init_promo_size,
duke@435 39 size_t init_survivor_size,
jwilhelm@6085 40 size_t space_alignment,
duke@435 41 double gc_pause_goal_sec,
duke@435 42 double gc_minor_pause_goal_sec,
duke@435 43 uint gc_cost_ratio) :
duke@435 44 AdaptiveSizePolicy(init_eden_size,
duke@435 45 init_promo_size,
duke@435 46 init_survivor_size,
duke@435 47 gc_pause_goal_sec,
duke@435 48 gc_cost_ratio),
jwilhelm@6084 49 _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin / 100.0),
jwilhelm@6085 50 _space_alignment(space_alignment),
duke@435 51 _live_at_last_full_gc(init_promo_size),
duke@435 52 _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec),
duke@435 53 _latest_major_mutator_interval_seconds(0),
duke@435 54 _young_gen_change_for_major_pause_count(0)
duke@435 55 {
duke@435 56 // Sizing policy statistics
duke@435 57 _avg_major_pause =
duke@435 58 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
duke@435 59 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435 60 _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
duke@435 61
duke@435 62 _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
duke@435 63 _major_pause_old_estimator =
duke@435 64 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435 65 _major_pause_young_estimator =
duke@435 66 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435 67 _major_collection_estimator =
duke@435 68 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
duke@435 69
duke@435 70 _young_gen_size_increment_supplement = YoungGenerationSizeSupplement;
duke@435 71 _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement;
duke@435 72
duke@435 73 // Start the timers
duke@435 74 _major_timer.start();
duke@435 75
duke@435 76 _old_gen_policy_is_ready = false;
duke@435 77 }
duke@435 78
duke@435 79 void PSAdaptiveSizePolicy::major_collection_begin() {
duke@435 80 // Update the interval time
duke@435 81 _major_timer.stop();
duke@435 82 // Save most recent collection time
duke@435 83 _latest_major_mutator_interval_seconds = _major_timer.seconds();
duke@435 84 _major_timer.reset();
duke@435 85 _major_timer.start();
duke@435 86 }
duke@435 87
duke@435 88 void PSAdaptiveSizePolicy::update_minor_pause_old_estimator(
duke@435 89 double minor_pause_in_ms) {
duke@435 90 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
duke@435 91 _minor_pause_old_estimator->update(promo_size_in_mbytes,
duke@435 92 minor_pause_in_ms);
duke@435 93 }
duke@435 94
duke@435 95 void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live,
duke@435 96 GCCause::Cause gc_cause) {
duke@435 97 // Update the pause time.
duke@435 98 _major_timer.stop();
duke@435 99
duke@435 100 if (gc_cause != GCCause::_java_lang_system_gc ||
duke@435 101 UseAdaptiveSizePolicyWithSystemGC) {
duke@435 102 double major_pause_in_seconds = _major_timer.seconds();
duke@435 103 double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS;
duke@435 104
duke@435 105 // Sample for performance counter
duke@435 106 _avg_major_pause->sample(major_pause_in_seconds);
duke@435 107
duke@435 108 // Cost of collection (unit-less)
duke@435 109 double collection_cost = 0.0;
duke@435 110 if ((_latest_major_mutator_interval_seconds > 0.0) &&
duke@435 111 (major_pause_in_seconds > 0.0)) {
duke@435 112 double interval_in_seconds =
duke@435 113 _latest_major_mutator_interval_seconds + major_pause_in_seconds;
duke@435 114 collection_cost =
duke@435 115 major_pause_in_seconds / interval_in_seconds;
duke@435 116 avg_major_gc_cost()->sample(collection_cost);
duke@435 117
duke@435 118 // Sample for performance counter
duke@435 119 _avg_major_interval->sample(interval_in_seconds);
duke@435 120 }
duke@435 121
duke@435 122 // Calculate variables used to estimate pause time vs. gen sizes
duke@435 123 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
duke@435 124 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
duke@435 125 _major_pause_old_estimator->update(promo_size_in_mbytes,
duke@435 126 major_pause_in_ms);
duke@435 127 _major_pause_young_estimator->update(eden_size_in_mbytes,
duke@435 128 major_pause_in_ms);
duke@435 129
duke@435 130 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 131 gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: "
duke@435 132 "major gc cost: %f average: %f", collection_cost,
duke@435 133 avg_major_gc_cost()->average());
duke@435 134 gclog_or_tty->print_cr(" major pause: %f major period %f",
duke@435 135 major_pause_in_ms,
duke@435 136 _latest_major_mutator_interval_seconds * MILLIUNITS);
duke@435 137 }
duke@435 138
duke@435 139 // Calculate variable used to estimate collection cost vs. gen sizes
duke@435 140 assert(collection_cost >= 0.0, "Expected to be non-negative");
duke@435 141 _major_collection_estimator->update(promo_size_in_mbytes,
duke@435 142 collection_cost);
duke@435 143 }
duke@435 144
duke@435 145 // Update the amount live at the end of a full GC
duke@435 146 _live_at_last_full_gc = amount_live;
duke@435 147
duke@435 148 // The policy does not have enough data until at least some major collections
duke@435 149 // have been done.
duke@435 150 if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) {
duke@435 151 _old_gen_policy_is_ready = true;
duke@435 152 }
duke@435 153
duke@435 154 // Interval times use this timer to measure the interval that
duke@435 155 // the mutator runs. Reset after the GC pause has been measured.
duke@435 156 _major_timer.reset();
duke@435 157 _major_timer.start();
duke@435 158 }
duke@435 159
duke@435 160 // If the remaining free space in the old generation is less that
duke@435 161 // that expected to be needed by the next collection, do a full
duke@435 162 // collection now.
duke@435 163 bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) {
duke@435 164
duke@435 165 // A similar test is done in the scavenge's should_attempt_scavenge(). If
duke@435 166 // this is changed, decide if that test should also be changed.
duke@435 167 bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes;
duke@435 168 if (PrintGCDetails && Verbose) {
duke@435 169 if (result) {
duke@435 170 gclog_or_tty->print(" full after scavenge: ");
duke@435 171 } else {
duke@435 172 gclog_or_tty->print(" no full after scavenge: ");
duke@435 173 }
duke@435 174 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
duke@435 175 " padded_average_promoted " SIZE_FORMAT
duke@435 176 " free in old gen " SIZE_FORMAT,
duke@435 177 (size_t) average_promoted_in_bytes(),
duke@435 178 (size_t) padded_average_promoted_in_bytes(),
duke@435 179 old_free_in_bytes);
duke@435 180 }
duke@435 181 return result;
duke@435 182 }
duke@435 183
duke@435 184 void PSAdaptiveSizePolicy::clear_generation_free_space_flags() {
duke@435 185
duke@435 186 AdaptiveSizePolicy::clear_generation_free_space_flags();
duke@435 187
duke@435 188 set_change_old_gen_for_min_pauses(0);
duke@435 189
duke@435 190 set_change_young_gen_for_maj_pauses(0);
duke@435 191 }
duke@435 192
duke@435 193 // If this is not a full GC, only test and modify the young generation.
duke@435 194
tamao@5192 195 void PSAdaptiveSizePolicy::compute_generations_free_space(
jmasa@1822 196 size_t young_live,
jmasa@1822 197 size_t eden_live,
jmasa@1822 198 size_t old_live,
jmasa@1822 199 size_t cur_eden,
jmasa@1822 200 size_t max_old_gen_size,
jmasa@1822 201 size_t max_eden_size,
tamao@5120 202 bool is_full_gc) {
tamao@5120 203 compute_eden_space_size(young_live,
tamao@5120 204 eden_live,
tamao@5120 205 cur_eden,
tamao@5120 206 max_eden_size,
tamao@5120 207 is_full_gc);
tamao@5120 208
tamao@5120 209 compute_old_gen_free_space(old_live,
tamao@5120 210 cur_eden,
tamao@5120 211 max_old_gen_size,
tamao@5120 212 is_full_gc);
tamao@5120 213 }
tamao@5120 214
tamao@5120 215 void PSAdaptiveSizePolicy::compute_eden_space_size(
tamao@5120 216 size_t young_live,
tamao@5120 217 size_t eden_live,
tamao@5120 218 size_t cur_eden,
tamao@5120 219 size_t max_eden_size,
tamao@5120 220 bool is_full_gc) {
duke@435 221
duke@435 222 // Update statistics
duke@435 223 // Time statistics are updated as we go, update footprint stats here
coleenp@4037 224 _avg_base_footprint->sample(BaseFootPrintEstimate);
duke@435 225 avg_young_live()->sample(young_live);
duke@435 226 avg_eden_live()->sample(eden_live);
tamao@5120 227
tamao@5120 228 // This code used to return if the policy was not ready , i.e.,
tamao@5120 229 // policy_is_ready() returning false. The intent was that
tamao@5120 230 // decisions below needed major collection times and so could
tamao@5120 231 // not be made before two major collections. A consequence was
tamao@5120 232 // adjustments to the young generation were not done until after
tamao@5120 233 // two major collections even if the minor collections times
tamao@5120 234 // exceeded the requested goals. Now let the young generation
tamao@5120 235 // adjust for the minor collection times. Major collection times
tamao@5120 236 // will be zero for the first collection and will naturally be
tamao@5120 237 // ignored. Tenured generation adjustments are only made at the
tamao@5120 238 // full collections so until the second major collection has
tamao@5120 239 // been reached, no tenured generation adjustments will be made.
tamao@5120 240
tamao@5120 241 // Until we know better, desired promotion size uses the last calculation
tamao@5120 242 size_t desired_promo_size = _promo_size;
tamao@5120 243
tamao@5120 244 // Start eden at the current value. The desired value that is stored
tamao@5120 245 // in _eden_size is not bounded by constraints of the heap and can
tamao@5120 246 // run away.
tamao@5120 247 //
tamao@5120 248 // As expected setting desired_eden_size to the current
tamao@5120 249 // value of desired_eden_size as a starting point
tamao@5120 250 // caused desired_eden_size to grow way too large and caused
tamao@5120 251 // an overflow down stream. It may have improved performance in
tamao@5120 252 // some case but is dangerous.
tamao@5120 253 size_t desired_eden_size = cur_eden;
tamao@5120 254
tamao@5120 255 // Cache some values. There's a bit of work getting these, so
tamao@5120 256 // we might save a little time.
tamao@5120 257 const double major_cost = major_gc_cost();
tamao@5120 258 const double minor_cost = minor_gc_cost();
tamao@5120 259
tamao@5120 260 // This method sets the desired eden size. That plus the
tamao@5120 261 // desired survivor space sizes sets the desired young generation
tamao@5120 262 // size. This methods does not know what the desired survivor
tamao@5120 263 // size is but expects that other policy will attempt to make
tamao@5120 264 // the survivor sizes compatible with the live data in the
tamao@5120 265 // young generation. This limit is an estimate of the space left
tamao@5120 266 // in the young generation after the survivor spaces have been
tamao@5120 267 // subtracted out.
tamao@5120 268 size_t eden_limit = max_eden_size;
tamao@5120 269
tamao@5120 270 const double gc_cost_limit = GCTimeLimit/100.0;
tamao@5120 271
tamao@5120 272 // Which way should we go?
tamao@5120 273 // if pause requirement is not met
tamao@5120 274 // adjust size of any generation with average paus exceeding
tamao@5120 275 // the pause limit. Adjust one pause at a time (the larger)
tamao@5120 276 // and only make adjustments for the major pause at full collections.
tamao@5120 277 // else if throughput requirement not met
tamao@5120 278 // adjust the size of the generation with larger gc time. Only
tamao@5120 279 // adjust one generation at a time.
tamao@5120 280 // else
tamao@5120 281 // adjust down the total heap size. Adjust down the larger of the
tamao@5120 282 // generations.
tamao@5120 283
tamao@5120 284 // Add some checks for a threshold for a change. For example,
tamao@5120 285 // a change less than the necessary alignment is probably not worth
tamao@5120 286 // attempting.
tamao@5120 287
tamao@5120 288
tamao@5120 289 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
tamao@5120 290 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
tamao@5120 291 //
tamao@5120 292 // Check pauses
tamao@5120 293 //
tamao@5120 294 // Make changes only to affect one of the pauses (the larger)
tamao@5120 295 // at a time.
tamao@5120 296 adjust_eden_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
tamao@5120 297
tamao@5120 298 } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
tamao@5120 299 // Adjust only for the minor pause time goal
tamao@5120 300 adjust_eden_for_minor_pause_time(is_full_gc, &desired_eden_size);
tamao@5120 301
tamao@5120 302 } else if(adjusted_mutator_cost() < _throughput_goal) {
tamao@5120 303 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
tamao@5120 304 // This sometimes resulted in skipping to the minimize footprint
tamao@5120 305 // code. Change this to try and reduce GC time if mutator time is
tamao@5120 306 // negative for whatever reason. Or for future consideration,
tamao@5120 307 // bail out of the code if mutator time is negative.
tamao@5120 308 //
tamao@5120 309 // Throughput
tamao@5120 310 //
tamao@5120 311 assert(major_cost >= 0.0, "major cost is < 0.0");
tamao@5120 312 assert(minor_cost >= 0.0, "minor cost is < 0.0");
tamao@5120 313 // Try to reduce the GC times.
tamao@5120 314 adjust_eden_for_throughput(is_full_gc, &desired_eden_size);
tamao@5120 315
tamao@5120 316 } else {
tamao@5120 317
tamao@5120 318 // Be conservative about reducing the footprint.
tamao@5120 319 // Do a minimum number of major collections first.
tamao@5120 320 // Have reasonable averages for major and minor collections costs.
tamao@5120 321 if (UseAdaptiveSizePolicyFootprintGoal &&
tamao@5120 322 young_gen_policy_is_ready() &&
tamao@5120 323 avg_major_gc_cost()->average() >= 0.0 &&
tamao@5120 324 avg_minor_gc_cost()->average() >= 0.0) {
tamao@5120 325 size_t desired_sum = desired_eden_size + desired_promo_size;
tamao@5120 326 desired_eden_size = adjust_eden_for_footprint(desired_eden_size, desired_sum);
tamao@5120 327 }
tamao@5120 328 }
tamao@5120 329
tamao@5120 330 // Note we make the same tests as in the code block below; the code
tamao@5120 331 // seems a little easier to read with the printing in another block.
tamao@5120 332 if (PrintAdaptiveSizePolicy) {
tamao@5120 333 if (desired_eden_size > eden_limit) {
tamao@5120 334 gclog_or_tty->print_cr(
tamao@5120 335 "PSAdaptiveSizePolicy::compute_eden_space_size limits:"
tamao@5120 336 " desired_eden_size: " SIZE_FORMAT
tamao@5120 337 " old_eden_size: " SIZE_FORMAT
tamao@5120 338 " eden_limit: " SIZE_FORMAT
tamao@5120 339 " cur_eden: " SIZE_FORMAT
tamao@5120 340 " max_eden_size: " SIZE_FORMAT
tamao@5120 341 " avg_young_live: " SIZE_FORMAT,
tamao@5120 342 desired_eden_size, _eden_size, eden_limit, cur_eden,
tamao@5120 343 max_eden_size, (size_t)avg_young_live()->average());
tamao@5120 344 }
tamao@5120 345 if (gc_cost() > gc_cost_limit) {
tamao@5120 346 gclog_or_tty->print_cr(
tamao@5120 347 "PSAdaptiveSizePolicy::compute_eden_space_size: gc time limit"
tamao@5120 348 " gc_cost: %f "
tamao@5120 349 " GCTimeLimit: %d",
tamao@5120 350 gc_cost(), GCTimeLimit);
tamao@5120 351 }
tamao@5120 352 }
tamao@5120 353
tamao@5120 354 // Align everything and make a final limit check
jwilhelm@6085 355 desired_eden_size = align_size_up(desired_eden_size, _space_alignment);
jwilhelm@6085 356 desired_eden_size = MAX2(desired_eden_size, _space_alignment);
tamao@5120 357
jwilhelm@6085 358 eden_limit = align_size_down(eden_limit, _space_alignment);
tamao@5120 359
tamao@5120 360 // And one last limit check, now that we've aligned things.
tamao@5120 361 if (desired_eden_size > eden_limit) {
tamao@5120 362 // If the policy says to get a larger eden but
tamao@5120 363 // is hitting the limit, don't decrease eden.
tamao@5120 364 // This can lead to a general drifting down of the
tamao@5120 365 // eden size. Let the tenuring calculation push more
tamao@5120 366 // into the old gen.
tamao@5120 367 desired_eden_size = MAX2(eden_limit, cur_eden);
tamao@5120 368 }
tamao@5120 369
tamao@5120 370 if (PrintAdaptiveSizePolicy) {
tamao@5120 371 // Timing stats
tamao@5120 372 gclog_or_tty->print(
tamao@5120 373 "PSAdaptiveSizePolicy::compute_eden_space_size: costs"
tamao@5120 374 " minor_time: %f"
tamao@5120 375 " major_cost: %f"
tamao@5120 376 " mutator_cost: %f"
tamao@5120 377 " throughput_goal: %f",
tamao@5120 378 minor_gc_cost(), major_gc_cost(), mutator_cost(),
tamao@5120 379 _throughput_goal);
tamao@5120 380
tamao@5120 381 // We give more details if Verbose is set
tamao@5120 382 if (Verbose) {
tamao@5120 383 gclog_or_tty->print( " minor_pause: %f"
tamao@5120 384 " major_pause: %f"
tamao@5120 385 " minor_interval: %f"
tamao@5120 386 " major_interval: %f"
tamao@5120 387 " pause_goal: %f",
tamao@5120 388 _avg_minor_pause->padded_average(),
tamao@5120 389 _avg_major_pause->padded_average(),
tamao@5120 390 _avg_minor_interval->average(),
tamao@5120 391 _avg_major_interval->average(),
tamao@5120 392 gc_pause_goal_sec());
tamao@5120 393 }
tamao@5120 394
tamao@5120 395 // Footprint stats
tamao@5120 396 gclog_or_tty->print( " live_space: " SIZE_FORMAT
tamao@5120 397 " free_space: " SIZE_FORMAT,
tamao@5120 398 live_space(), free_space());
tamao@5120 399 // More detail
tamao@5120 400 if (Verbose) {
tamao@5120 401 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
tamao@5120 402 " avg_young_live: " SIZE_FORMAT
tamao@5120 403 " avg_old_live: " SIZE_FORMAT,
tamao@5120 404 (size_t)_avg_base_footprint->average(),
tamao@5120 405 (size_t)avg_young_live()->average(),
tamao@5120 406 (size_t)avg_old_live()->average());
tamao@5120 407 }
tamao@5120 408
tamao@5120 409 // And finally, our old and new sizes.
tamao@5120 410 gclog_or_tty->print(" old_eden_size: " SIZE_FORMAT
tamao@5120 411 " desired_eden_size: " SIZE_FORMAT,
tamao@5120 412 _eden_size, desired_eden_size);
tamao@5120 413 gclog_or_tty->cr();
tamao@5120 414 }
tamao@5120 415
tamao@5120 416 set_eden_size(desired_eden_size);
tamao@5120 417 }
tamao@5120 418
tamao@5120 419 void PSAdaptiveSizePolicy::compute_old_gen_free_space(
tamao@5120 420 size_t old_live,
tamao@5120 421 size_t cur_eden,
tamao@5120 422 size_t max_old_gen_size,
tamao@5120 423 bool is_full_gc) {
tamao@5120 424
tamao@5120 425 // Update statistics
tamao@5120 426 // Time statistics are updated as we go, update footprint stats here
duke@435 427 if (is_full_gc) {
duke@435 428 // old_live is only accurate after a full gc
duke@435 429 avg_old_live()->sample(old_live);
duke@435 430 }
duke@435 431
duke@435 432 // This code used to return if the policy was not ready , i.e.,
duke@435 433 // policy_is_ready() returning false. The intent was that
duke@435 434 // decisions below needed major collection times and so could
duke@435 435 // not be made before two major collections. A consequence was
duke@435 436 // adjustments to the young generation were not done until after
duke@435 437 // two major collections even if the minor collections times
duke@435 438 // exceeded the requested goals. Now let the young generation
duke@435 439 // adjust for the minor collection times. Major collection times
duke@435 440 // will be zero for the first collection and will naturally be
duke@435 441 // ignored. Tenured generation adjustments are only made at the
duke@435 442 // full collections so until the second major collection has
duke@435 443 // been reached, no tenured generation adjustments will be made.
duke@435 444
duke@435 445 // Until we know better, desired promotion size uses the last calculation
duke@435 446 size_t desired_promo_size = _promo_size;
duke@435 447
duke@435 448 // Start eden at the current value. The desired value that is stored
duke@435 449 // in _eden_size is not bounded by constraints of the heap and can
duke@435 450 // run away.
duke@435 451 //
duke@435 452 // As expected setting desired_eden_size to the current
duke@435 453 // value of desired_eden_size as a starting point
duke@435 454 // caused desired_eden_size to grow way too large and caused
duke@435 455 // an overflow down stream. It may have improved performance in
duke@435 456 // some case but is dangerous.
duke@435 457 size_t desired_eden_size = cur_eden;
duke@435 458
duke@435 459 // Cache some values. There's a bit of work getting these, so
duke@435 460 // we might save a little time.
duke@435 461 const double major_cost = major_gc_cost();
duke@435 462 const double minor_cost = minor_gc_cost();
duke@435 463
duke@435 464 // Limits on our growth
duke@435 465 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
duke@435 466
duke@435 467 // But don't force a promo size below the current promo size. Otherwise,
duke@435 468 // the promo size will shrink for no good reason.
duke@435 469 promo_limit = MAX2(promo_limit, _promo_size);
duke@435 470
duke@435 471 const double gc_cost_limit = GCTimeLimit/100.0;
duke@435 472
duke@435 473 // Which way should we go?
duke@435 474 // if pause requirement is not met
duke@435 475 // adjust size of any generation with average paus exceeding
duke@435 476 // the pause limit. Adjust one pause at a time (the larger)
duke@435 477 // and only make adjustments for the major pause at full collections.
duke@435 478 // else if throughput requirement not met
duke@435 479 // adjust the size of the generation with larger gc time. Only
duke@435 480 // adjust one generation at a time.
duke@435 481 // else
duke@435 482 // adjust down the total heap size. Adjust down the larger of the
duke@435 483 // generations.
duke@435 484
duke@435 485 // Add some checks for a threshhold for a change. For example,
duke@435 486 // a change less than the necessary alignment is probably not worth
duke@435 487 // attempting.
duke@435 488
duke@435 489 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
duke@435 490 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
duke@435 491 //
duke@435 492 // Check pauses
duke@435 493 //
duke@435 494 // Make changes only to affect one of the pauses (the larger)
duke@435 495 // at a time.
tamao@5120 496 if (is_full_gc) {
tamao@5120 497 set_decide_at_full_gc(decide_at_full_gc_true);
tamao@5120 498 adjust_promo_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
tamao@5120 499 }
duke@435 500 } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
duke@435 501 // Adjust only for the minor pause time goal
tamao@5120 502 adjust_promo_for_minor_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
duke@435 503 } else if(adjusted_mutator_cost() < _throughput_goal) {
duke@435 504 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
duke@435 505 // This sometimes resulted in skipping to the minimize footprint
duke@435 506 // code. Change this to try and reduce GC time if mutator time is
duke@435 507 // negative for whatever reason. Or for future consideration,
duke@435 508 // bail out of the code if mutator time is negative.
duke@435 509 //
duke@435 510 // Throughput
duke@435 511 //
duke@435 512 assert(major_cost >= 0.0, "major cost is < 0.0");
duke@435 513 assert(minor_cost >= 0.0, "minor cost is < 0.0");
duke@435 514 // Try to reduce the GC times.
tamao@5120 515 if (is_full_gc) {
tamao@5120 516 set_decide_at_full_gc(decide_at_full_gc_true);
tamao@5120 517 adjust_promo_for_throughput(is_full_gc, &desired_promo_size);
tamao@5120 518 }
duke@435 519 } else {
duke@435 520
duke@435 521 // Be conservative about reducing the footprint.
duke@435 522 // Do a minimum number of major collections first.
duke@435 523 // Have reasonable averages for major and minor collections costs.
duke@435 524 if (UseAdaptiveSizePolicyFootprintGoal &&
duke@435 525 young_gen_policy_is_ready() &&
duke@435 526 avg_major_gc_cost()->average() >= 0.0 &&
duke@435 527 avg_minor_gc_cost()->average() >= 0.0) {
duke@435 528 if (is_full_gc) {
duke@435 529 set_decide_at_full_gc(decide_at_full_gc_true);
tamao@5120 530 size_t desired_sum = desired_eden_size + desired_promo_size;
tamao@5120 531 desired_promo_size = adjust_promo_for_footprint(desired_promo_size, desired_sum);
duke@435 532 }
duke@435 533 }
duke@435 534 }
duke@435 535
duke@435 536 // Note we make the same tests as in the code block below; the code
duke@435 537 // seems a little easier to read with the printing in another block.
duke@435 538 if (PrintAdaptiveSizePolicy) {
duke@435 539 if (desired_promo_size > promo_limit) {
duke@435 540 // "free_in_old_gen" was the original value for used for promo_limit
duke@435 541 size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
duke@435 542 gclog_or_tty->print_cr(
tamao@5120 543 "PSAdaptiveSizePolicy::compute_old_gen_free_space limits:"
duke@435 544 " desired_promo_size: " SIZE_FORMAT
duke@435 545 " promo_limit: " SIZE_FORMAT
duke@435 546 " free_in_old_gen: " SIZE_FORMAT
duke@435 547 " max_old_gen_size: " SIZE_FORMAT
duke@435 548 " avg_old_live: " SIZE_FORMAT,
duke@435 549 desired_promo_size, promo_limit, free_in_old_gen,
duke@435 550 max_old_gen_size, (size_t) avg_old_live()->average());
duke@435 551 }
duke@435 552 if (gc_cost() > gc_cost_limit) {
duke@435 553 gclog_or_tty->print_cr(
tamao@5120 554 "PSAdaptiveSizePolicy::compute_old_gen_free_space: gc time limit"
duke@435 555 " gc_cost: %f "
duke@435 556 " GCTimeLimit: %d",
duke@435 557 gc_cost(), GCTimeLimit);
duke@435 558 }
duke@435 559 }
duke@435 560
duke@435 561 // Align everything and make a final limit check
jwilhelm@6085 562 desired_promo_size = align_size_up(desired_promo_size, _space_alignment);
jwilhelm@6085 563 desired_promo_size = MAX2(desired_promo_size, _space_alignment);
duke@435 564
jwilhelm@6085 565 promo_limit = align_size_down(promo_limit, _space_alignment);
duke@435 566
duke@435 567 // And one last limit check, now that we've aligned things.
duke@435 568 desired_promo_size = MIN2(desired_promo_size, promo_limit);
duke@435 569
duke@435 570 if (PrintAdaptiveSizePolicy) {
duke@435 571 // Timing stats
duke@435 572 gclog_or_tty->print(
tamao@5120 573 "PSAdaptiveSizePolicy::compute_old_gen_free_space: costs"
duke@435 574 " minor_time: %f"
duke@435 575 " major_cost: %f"
duke@435 576 " mutator_cost: %f"
duke@435 577 " throughput_goal: %f",
duke@435 578 minor_gc_cost(), major_gc_cost(), mutator_cost(),
duke@435 579 _throughput_goal);
duke@435 580
duke@435 581 // We give more details if Verbose is set
duke@435 582 if (Verbose) {
duke@435 583 gclog_or_tty->print( " minor_pause: %f"
duke@435 584 " major_pause: %f"
duke@435 585 " minor_interval: %f"
duke@435 586 " major_interval: %f"
duke@435 587 " pause_goal: %f",
duke@435 588 _avg_minor_pause->padded_average(),
duke@435 589 _avg_major_pause->padded_average(),
duke@435 590 _avg_minor_interval->average(),
duke@435 591 _avg_major_interval->average(),
duke@435 592 gc_pause_goal_sec());
duke@435 593 }
duke@435 594
duke@435 595 // Footprint stats
duke@435 596 gclog_or_tty->print( " live_space: " SIZE_FORMAT
duke@435 597 " free_space: " SIZE_FORMAT,
duke@435 598 live_space(), free_space());
duke@435 599 // More detail
duke@435 600 if (Verbose) {
duke@435 601 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
duke@435 602 " avg_young_live: " SIZE_FORMAT
duke@435 603 " avg_old_live: " SIZE_FORMAT,
duke@435 604 (size_t)_avg_base_footprint->average(),
duke@435 605 (size_t)avg_young_live()->average(),
duke@435 606 (size_t)avg_old_live()->average());
duke@435 607 }
duke@435 608
duke@435 609 // And finally, our old and new sizes.
duke@435 610 gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT
tamao@5120 611 " desired_promo_size: " SIZE_FORMAT,
tamao@5120 612 _promo_size, desired_promo_size);
duke@435 613 gclog_or_tty->cr();
duke@435 614 }
duke@435 615
duke@435 616 set_promo_size(desired_promo_size);
tamao@5120 617 }
duke@435 618
duke@435 619 void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) {
duke@435 620 // Decay the supplemental increment? Decay the supplement growth
duke@435 621 // factor even if it is not used. It is only meant to give a boost
duke@435 622 // to the initial growth and if it is not used, then it was not
duke@435 623 // needed.
duke@435 624 if (is_full_gc) {
duke@435 625 // Don't wait for the threshold value for the major collections. If
duke@435 626 // here, the supplemental growth term was used and should decay.
duke@435 627 if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay)
duke@435 628 == 0) {
duke@435 629 _old_gen_size_increment_supplement =
duke@435 630 _old_gen_size_increment_supplement >> 1;
duke@435 631 }
duke@435 632 } else {
duke@435 633 if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) &&
duke@435 634 (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) {
duke@435 635 _young_gen_size_increment_supplement =
duke@435 636 _young_gen_size_increment_supplement >> 1;
duke@435 637 }
duke@435 638 }
duke@435 639 }
duke@435 640
tamao@5120 641 void PSAdaptiveSizePolicy::adjust_promo_for_minor_pause_time(bool is_full_gc,
duke@435 642 size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) {
duke@435 643
tamao@5120 644 if (PSAdjustTenuredGenForMinorPause) {
tamao@5120 645 if (is_full_gc) {
tamao@5120 646 set_decide_at_full_gc(decide_at_full_gc_true);
tamao@5120 647 }
tamao@5120 648 // If the desired eden size is as small as it will get,
tamao@5120 649 // try to adjust the old gen size.
jwilhelm@6085 650 if (*desired_eden_size_ptr <= _space_alignment) {
tamao@5120 651 // Vary the old gen size to reduce the young gen pause. This
tamao@5120 652 // may not be a good idea. This is just a test.
tamao@5120 653 if (minor_pause_old_estimator()->decrement_will_decrease()) {
tamao@5120 654 set_change_old_gen_for_min_pauses(decrease_old_gen_for_min_pauses_true);
tamao@5120 655 *desired_promo_size_ptr =
tamao@5120 656 _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr);
tamao@5120 657 } else {
tamao@5120 658 set_change_old_gen_for_min_pauses(increase_old_gen_for_min_pauses_true);
tamao@5120 659 size_t promo_heap_delta =
tamao@5120 660 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
tamao@5120 661 if ((*desired_promo_size_ptr + promo_heap_delta) >
tamao@5120 662 *desired_promo_size_ptr) {
tamao@5120 663 *desired_promo_size_ptr =
tamao@5120 664 _promo_size + promo_heap_delta;
tamao@5120 665 }
tamao@5120 666 }
tamao@5120 667 }
tamao@5120 668 }
tamao@5120 669 }
tamao@5120 670
tamao@5120 671 void PSAdaptiveSizePolicy::adjust_eden_for_minor_pause_time(bool is_full_gc,
tamao@5120 672 size_t* desired_eden_size_ptr) {
tamao@5120 673
duke@435 674 // Adjust the young generation size to reduce pause time of
duke@435 675 // of collections.
duke@435 676 //
duke@435 677 // The AdaptiveSizePolicyInitializingSteps test is not used
duke@435 678 // here. It has not seemed to be needed but perhaps should
duke@435 679 // be added for consistency.
duke@435 680 if (minor_pause_young_estimator()->decrement_will_decrease()) {
duke@435 681 // reduce eden size
duke@435 682 set_change_young_gen_for_min_pauses(
duke@435 683 decrease_young_gen_for_min_pauses_true);
duke@435 684 *desired_eden_size_ptr = *desired_eden_size_ptr -
duke@435 685 eden_decrement_aligned_down(*desired_eden_size_ptr);
duke@435 686 } else {
duke@435 687 // EXPERIMENTAL ADJUSTMENT
duke@435 688 // Only record that the estimator indicated such an action.
duke@435 689 // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta;
duke@435 690 set_change_young_gen_for_min_pauses(
duke@435 691 increase_young_gen_for_min_pauses_true);
duke@435 692 }
duke@435 693 }
duke@435 694
tamao@5120 695 void PSAdaptiveSizePolicy::adjust_promo_for_pause_time(bool is_full_gc,
duke@435 696 size_t* desired_promo_size_ptr,
duke@435 697 size_t* desired_eden_size_ptr) {
duke@435 698
duke@435 699 size_t promo_heap_delta = 0;
tamao@5120 700 // Add some checks for a threshold for a change. For example,
duke@435 701 // a change less than the required alignment is probably not worth
duke@435 702 // attempting.
duke@435 703
duke@435 704 if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
tamao@5120 705 adjust_promo_for_minor_pause_time(is_full_gc, desired_promo_size_ptr, desired_eden_size_ptr);
duke@435 706 // major pause adjustments
duke@435 707 } else if (is_full_gc) {
duke@435 708 // Adjust for the major pause time only at full gc's because the
duke@435 709 // affects of a change can only be seen at full gc's.
duke@435 710
duke@435 711 // Reduce old generation size to reduce pause?
duke@435 712 if (major_pause_old_estimator()->decrement_will_decrease()) {
duke@435 713 // reduce old generation size
duke@435 714 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
duke@435 715 promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr);
duke@435 716 *desired_promo_size_ptr = _promo_size - promo_heap_delta;
duke@435 717 } else {
duke@435 718 // EXPERIMENTAL ADJUSTMENT
duke@435 719 // Only record that the estimator indicated such an action.
duke@435 720 // *desired_promo_size_ptr = _promo_size +
duke@435 721 // promo_increment_aligned_up(*desired_promo_size_ptr);
duke@435 722 set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true);
duke@435 723 }
tamao@5120 724 }
tamao@5120 725
tamao@5120 726 if (PrintAdaptiveSizePolicy && Verbose) {
tamao@5120 727 gclog_or_tty->print_cr(
tamao@5192 728 "PSAdaptiveSizePolicy::adjust_promo_for_pause_time "
tamao@5120 729 "adjusting gen sizes for major pause (avg %f goal %f). "
tamao@5120 730 "desired_promo_size " SIZE_FORMAT " promo delta " SIZE_FORMAT,
tamao@5120 731 _avg_major_pause->average(), gc_pause_goal_sec(),
tamao@5120 732 *desired_promo_size_ptr, promo_heap_delta);
tamao@5120 733 }
tamao@5120 734 }
tamao@5120 735
tamao@5120 736 void PSAdaptiveSizePolicy::adjust_eden_for_pause_time(bool is_full_gc,
tamao@5120 737 size_t* desired_promo_size_ptr,
tamao@5120 738 size_t* desired_eden_size_ptr) {
tamao@5120 739
tamao@5120 740 size_t eden_heap_delta = 0;
tamao@5120 741 // Add some checks for a threshold for a change. For example,
tamao@5120 742 // a change less than the required alignment is probably not worth
tamao@5120 743 // attempting.
tamao@5120 744 if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
tamao@5120 745 adjust_eden_for_minor_pause_time(is_full_gc,
tamao@5120 746 desired_eden_size_ptr);
tamao@5120 747 // major pause adjustments
tamao@5120 748 } else if (is_full_gc) {
tamao@5120 749 // Adjust for the major pause time only at full gc's because the
tamao@5120 750 // affects of a change can only be seen at full gc's.
duke@435 751 if (PSAdjustYoungGenForMajorPause) {
duke@435 752 // If the promo size is at the minimum (i.e., the old gen
duke@435 753 // size will not actually decrease), consider changing the
duke@435 754 // young gen size.
jwilhelm@6085 755 if (*desired_promo_size_ptr < _space_alignment) {
duke@435 756 // If increasing the young generation will decrease the old gen
duke@435 757 // pause, do it.
duke@435 758 // During startup there is noise in the statistics for deciding
duke@435 759 // on whether to increase or decrease the young gen size. For
duke@435 760 // some number of iterations, just try to increase the young
duke@435 761 // gen size if the major pause is too long to try and establish
duke@435 762 // good statistics for later decisions.
duke@435 763 if (major_pause_young_estimator()->increment_will_decrease() ||
duke@435 764 (_young_gen_change_for_major_pause_count
duke@435 765 <= AdaptiveSizePolicyInitializingSteps)) {
duke@435 766 set_change_young_gen_for_maj_pauses(
duke@435 767 increase_young_gen_for_maj_pauses_true);
duke@435 768 eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr);
duke@435 769 *desired_eden_size_ptr = _eden_size + eden_heap_delta;
duke@435 770 _young_gen_change_for_major_pause_count++;
duke@435 771 } else {
duke@435 772 // Record that decreasing the young gen size would decrease
duke@435 773 // the major pause
duke@435 774 set_change_young_gen_for_maj_pauses(
duke@435 775 decrease_young_gen_for_maj_pauses_true);
duke@435 776 eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr);
duke@435 777 *desired_eden_size_ptr = _eden_size - eden_heap_delta;
duke@435 778 }
duke@435 779 }
duke@435 780 }
duke@435 781 }
duke@435 782
duke@435 783 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 784 gclog_or_tty->print_cr(
tamao@5192 785 "PSAdaptiveSizePolicy::adjust_eden_for_pause_time "
duke@435 786 "adjusting gen sizes for major pause (avg %f goal %f). "
tamao@5120 787 "desired_eden_size " SIZE_FORMAT " eden delta " SIZE_FORMAT,
duke@435 788 _avg_major_pause->average(), gc_pause_goal_sec(),
tamao@5120 789 *desired_eden_size_ptr, eden_heap_delta);
duke@435 790 }
duke@435 791 }
duke@435 792
tamao@5120 793 void PSAdaptiveSizePolicy::adjust_promo_for_throughput(bool is_full_gc,
tamao@5120 794 size_t* desired_promo_size_ptr) {
duke@435 795
tamao@5120 796 // Add some checks for a threshold for a change. For example,
duke@435 797 // a change less than the required alignment is probably not worth
duke@435 798 // attempting.
duke@435 799
duke@435 800 if ((gc_cost() + mutator_cost()) == 0.0) {
duke@435 801 return;
duke@435 802 }
duke@435 803
duke@435 804 if (PrintAdaptiveSizePolicy && Verbose) {
tamao@5120 805 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_promo_for_throughput("
tamao@5120 806 "is_full: %d, promo: " SIZE_FORMAT "): ",
tamao@5120 807 is_full_gc, *desired_promo_size_ptr);
duke@435 808 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
duke@435 809 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
duke@435 810 }
duke@435 811
duke@435 812 // Tenured generation
duke@435 813 if (is_full_gc) {
duke@435 814 // Calculate the change to use for the tenured gen.
duke@435 815 size_t scaled_promo_heap_delta = 0;
duke@435 816 // Can the increment to the generation be scaled?
duke@435 817 if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) {
duke@435 818 size_t promo_heap_delta =
duke@435 819 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
duke@435 820 double scale_by_ratio = major_gc_cost() / gc_cost();
duke@435 821 scaled_promo_heap_delta =
duke@435 822 (size_t) (scale_by_ratio * (double) promo_heap_delta);
duke@435 823 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 824 gclog_or_tty->print_cr(
duke@435 825 "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
duke@435 826 SIZE_FORMAT,
duke@435 827 promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta);
duke@435 828 }
duke@435 829 } else if (major_gc_cost() >= 0.0) {
duke@435 830 // Scaling is not going to work. If the major gc time is the
duke@435 831 // larger, give it a full increment.
duke@435 832 if (major_gc_cost() >= minor_gc_cost()) {
duke@435 833 scaled_promo_heap_delta =
duke@435 834 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
duke@435 835 }
duke@435 836 } else {
duke@435 837 // Don't expect to get here but it's ok if it does
duke@435 838 // in the product build since the delta will be 0
duke@435 839 // and nothing will change.
duke@435 840 assert(false, "Unexpected value for gc costs");
duke@435 841 }
duke@435 842
duke@435 843 switch (AdaptiveSizeThroughPutPolicy) {
duke@435 844 case 1:
duke@435 845 // Early in the run the statistics might not be good. Until
duke@435 846 // a specific number of collections have been, use the heuristic
duke@435 847 // that a larger generation size means lower collection costs.
duke@435 848 if (major_collection_estimator()->increment_will_decrease() ||
duke@435 849 (_old_gen_change_for_major_throughput
duke@435 850 <= AdaptiveSizePolicyInitializingSteps)) {
duke@435 851 // Increase tenured generation size to reduce major collection cost
duke@435 852 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
duke@435 853 *desired_promo_size_ptr) {
duke@435 854 *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta;
duke@435 855 }
duke@435 856 set_change_old_gen_for_throughput(
duke@435 857 increase_old_gen_for_throughput_true);
duke@435 858 _old_gen_change_for_major_throughput++;
duke@435 859 } else {
duke@435 860 // EXPERIMENTAL ADJUSTMENT
duke@435 861 // Record that decreasing the old gen size would decrease
duke@435 862 // the major collection cost but don't do it.
duke@435 863 // *desired_promo_size_ptr = _promo_size -
duke@435 864 // promo_decrement_aligned_down(*desired_promo_size_ptr);
duke@435 865 set_change_old_gen_for_throughput(
duke@435 866 decrease_old_gen_for_throughput_true);
duke@435 867 }
duke@435 868
duke@435 869 break;
duke@435 870 default:
duke@435 871 // Simplest strategy
duke@435 872 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
duke@435 873 *desired_promo_size_ptr) {
duke@435 874 *desired_promo_size_ptr = *desired_promo_size_ptr +
duke@435 875 scaled_promo_heap_delta;
duke@435 876 }
duke@435 877 set_change_old_gen_for_throughput(
duke@435 878 increase_old_gen_for_throughput_true);
duke@435 879 _old_gen_change_for_major_throughput++;
duke@435 880 }
duke@435 881
duke@435 882 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 883 gclog_or_tty->print_cr(
duke@435 884 "adjusting tenured gen for throughput (avg %f goal %f). "
duke@435 885 "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT ,
duke@435 886 mutator_cost(), _throughput_goal,
duke@435 887 *desired_promo_size_ptr, scaled_promo_heap_delta);
duke@435 888 }
duke@435 889 }
tamao@5120 890 }
tamao@5120 891
tamao@5120 892 void PSAdaptiveSizePolicy::adjust_eden_for_throughput(bool is_full_gc,
tamao@5120 893 size_t* desired_eden_size_ptr) {
tamao@5120 894
tamao@5120 895 // Add some checks for a threshold for a change. For example,
tamao@5120 896 // a change less than the required alignment is probably not worth
tamao@5120 897 // attempting.
tamao@5120 898
tamao@5120 899 if ((gc_cost() + mutator_cost()) == 0.0) {
tamao@5120 900 return;
tamao@5120 901 }
tamao@5120 902
tamao@5120 903 if (PrintAdaptiveSizePolicy && Verbose) {
tamao@5120 904 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_eden_for_throughput("
tamao@5120 905 "is_full: %d, cur_eden: " SIZE_FORMAT "): ",
tamao@5120 906 is_full_gc, *desired_eden_size_ptr);
tamao@5120 907 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
tamao@5120 908 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
tamao@5120 909 }
duke@435 910
duke@435 911 // Young generation
duke@435 912 size_t scaled_eden_heap_delta = 0;
duke@435 913 // Can the increment to the generation be scaled?
duke@435 914 if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) {
duke@435 915 size_t eden_heap_delta =
duke@435 916 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
duke@435 917 double scale_by_ratio = minor_gc_cost() / gc_cost();
duke@435 918 assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong");
duke@435 919 scaled_eden_heap_delta =
duke@435 920 (size_t) (scale_by_ratio * (double) eden_heap_delta);
duke@435 921 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 922 gclog_or_tty->print_cr(
duke@435 923 "Scaled eden increment: " SIZE_FORMAT " by %f down to "
duke@435 924 SIZE_FORMAT,
duke@435 925 eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta);
duke@435 926 }
duke@435 927 } else if (minor_gc_cost() >= 0.0) {
duke@435 928 // Scaling is not going to work. If the minor gc time is the
duke@435 929 // larger, give it a full increment.
duke@435 930 if (minor_gc_cost() > major_gc_cost()) {
duke@435 931 scaled_eden_heap_delta =
duke@435 932 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
duke@435 933 }
duke@435 934 } else {
duke@435 935 // Don't expect to get here but it's ok if it does
duke@435 936 // in the product build since the delta will be 0
duke@435 937 // and nothing will change.
duke@435 938 assert(false, "Unexpected value for gc costs");
duke@435 939 }
duke@435 940
duke@435 941 // Use a heuristic for some number of collections to give
duke@435 942 // the averages time to settle down.
duke@435 943 switch (AdaptiveSizeThroughPutPolicy) {
duke@435 944 case 1:
duke@435 945 if (minor_collection_estimator()->increment_will_decrease() ||
duke@435 946 (_young_gen_change_for_minor_throughput
duke@435 947 <= AdaptiveSizePolicyInitializingSteps)) {
duke@435 948 // Expand young generation size to reduce frequency of
duke@435 949 // of collections.
duke@435 950 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
duke@435 951 *desired_eden_size_ptr) {
duke@435 952 *desired_eden_size_ptr =
duke@435 953 *desired_eden_size_ptr + scaled_eden_heap_delta;
duke@435 954 }
duke@435 955 set_change_young_gen_for_throughput(
duke@435 956 increase_young_gen_for_througput_true);
duke@435 957 _young_gen_change_for_minor_throughput++;
duke@435 958 } else {
duke@435 959 // EXPERIMENTAL ADJUSTMENT
duke@435 960 // Record that decreasing the young gen size would decrease
duke@435 961 // the minor collection cost but don't do it.
duke@435 962 // *desired_eden_size_ptr = _eden_size -
duke@435 963 // eden_decrement_aligned_down(*desired_eden_size_ptr);
duke@435 964 set_change_young_gen_for_throughput(
duke@435 965 decrease_young_gen_for_througput_true);
duke@435 966 }
duke@435 967 break;
duke@435 968 default:
duke@435 969 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
duke@435 970 *desired_eden_size_ptr) {
duke@435 971 *desired_eden_size_ptr =
duke@435 972 *desired_eden_size_ptr + scaled_eden_heap_delta;
duke@435 973 }
duke@435 974 set_change_young_gen_for_throughput(
duke@435 975 increase_young_gen_for_througput_true);
duke@435 976 _young_gen_change_for_minor_throughput++;
duke@435 977 }
duke@435 978
duke@435 979 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 980 gclog_or_tty->print_cr(
duke@435 981 "adjusting eden for throughput (avg %f goal %f). desired_eden_size "
duke@435 982 SIZE_FORMAT " eden delta " SIZE_FORMAT "\n",
duke@435 983 mutator_cost(), _throughput_goal,
duke@435 984 *desired_eden_size_ptr, scaled_eden_heap_delta);
duke@435 985 }
duke@435 986 }
duke@435 987
duke@435 988 size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint(
duke@435 989 size_t desired_promo_size, size_t desired_sum) {
duke@435 990 assert(desired_promo_size <= desired_sum, "Inconsistent parameters");
duke@435 991 set_decrease_for_footprint(decrease_old_gen_for_footprint_true);
duke@435 992
duke@435 993 size_t change = promo_decrement(desired_promo_size);
duke@435 994 change = scale_down(change, desired_promo_size, desired_sum);
duke@435 995
duke@435 996 size_t reduced_size = desired_promo_size - change;
duke@435 997
duke@435 998 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 999 gclog_or_tty->print_cr(
tamao@5192 1000 "AdaptiveSizePolicy::adjust_promo_for_footprint "
duke@435 1001 "adjusting tenured gen for footprint. "
duke@435 1002 "starting promo size " SIZE_FORMAT
duke@435 1003 " reduced promo size " SIZE_FORMAT,
duke@435 1004 " promo delta " SIZE_FORMAT,
duke@435 1005 desired_promo_size, reduced_size, change );
duke@435 1006 }
duke@435 1007
duke@435 1008 assert(reduced_size <= desired_promo_size, "Inconsistent result");
duke@435 1009 return reduced_size;
duke@435 1010 }
duke@435 1011
duke@435 1012 size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint(
duke@435 1013 size_t desired_eden_size, size_t desired_sum) {
duke@435 1014 assert(desired_eden_size <= desired_sum, "Inconsistent parameters");
duke@435 1015 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
duke@435 1016
duke@435 1017 size_t change = eden_decrement(desired_eden_size);
duke@435 1018 change = scale_down(change, desired_eden_size, desired_sum);
duke@435 1019
duke@435 1020 size_t reduced_size = desired_eden_size - change;
duke@435 1021
duke@435 1022 if (PrintAdaptiveSizePolicy && Verbose) {
duke@435 1023 gclog_or_tty->print_cr(
tamao@5192 1024 "AdaptiveSizePolicy::adjust_eden_for_footprint "
duke@435 1025 "adjusting eden for footprint. "
duke@435 1026 " starting eden size " SIZE_FORMAT
duke@435 1027 " reduced eden size " SIZE_FORMAT
duke@435 1028 " eden delta " SIZE_FORMAT,
duke@435 1029 desired_eden_size, reduced_size, change);
duke@435 1030 }
duke@435 1031
duke@435 1032 assert(reduced_size <= desired_eden_size, "Inconsistent result");
duke@435 1033 return reduced_size;
duke@435 1034 }
duke@435 1035
duke@435 1036 // Scale down "change" by the factor
duke@435 1037 // part / total
duke@435 1038 // Don't align the results.
duke@435 1039
duke@435 1040 size_t PSAdaptiveSizePolicy::scale_down(size_t change,
duke@435 1041 double part,
duke@435 1042 double total) {
duke@435 1043 assert(part <= total, "Inconsistent input");
duke@435 1044 size_t reduced_change = change;
duke@435 1045 if (total > 0) {
duke@435 1046 double fraction = part / total;
duke@435 1047 reduced_change = (size_t) (fraction * (double) change);
duke@435 1048 }
duke@435 1049 assert(reduced_change <= change, "Inconsistent result");
duke@435 1050 return reduced_change;
duke@435 1051 }
duke@435 1052
duke@435 1053 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden,
duke@435 1054 uint percent_change) {
duke@435 1055 size_t eden_heap_delta;
duke@435 1056 eden_heap_delta = cur_eden / 100 * percent_change;
duke@435 1057 return eden_heap_delta;
duke@435 1058 }
duke@435 1059
duke@435 1060 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) {
duke@435 1061 return eden_increment(cur_eden, YoungGenerationSizeIncrement);
duke@435 1062 }
duke@435 1063
duke@435 1064 size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
duke@435 1065 size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement);
jwilhelm@6085 1066 return align_size_up(result, _space_alignment);
duke@435 1067 }
duke@435 1068
duke@435 1069 size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) {
duke@435 1070 size_t result = eden_increment(cur_eden);
jwilhelm@6085 1071 return align_size_down(result, _space_alignment);
duke@435 1072 }
duke@435 1073
duke@435 1074 size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up(
duke@435 1075 size_t cur_eden) {
duke@435 1076 size_t result = eden_increment(cur_eden,
duke@435 1077 YoungGenerationSizeIncrement + _young_gen_size_increment_supplement);
jwilhelm@6085 1078 return align_size_up(result, _space_alignment);
duke@435 1079 }
duke@435 1080
duke@435 1081 size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
duke@435 1082 size_t eden_heap_delta = eden_decrement(cur_eden);
jwilhelm@6085 1083 return align_size_down(eden_heap_delta, _space_alignment);
duke@435 1084 }
duke@435 1085
duke@435 1086 size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
duke@435 1087 size_t eden_heap_delta = eden_increment(cur_eden) /
duke@435 1088 AdaptiveSizeDecrementScaleFactor;
duke@435 1089 return eden_heap_delta;
duke@435 1090 }
duke@435 1091
duke@435 1092 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo,
duke@435 1093 uint percent_change) {
duke@435 1094 size_t promo_heap_delta;
duke@435 1095 promo_heap_delta = cur_promo / 100 * percent_change;
duke@435 1096 return promo_heap_delta;
duke@435 1097 }
duke@435 1098
duke@435 1099 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) {
duke@435 1100 return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
duke@435 1101 }
duke@435 1102
duke@435 1103 size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
duke@435 1104 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
jwilhelm@6085 1105 return align_size_up(result, _space_alignment);
duke@435 1106 }
duke@435 1107
duke@435 1108 size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) {
duke@435 1109 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
jwilhelm@6085 1110 return align_size_down(result, _space_alignment);
duke@435 1111 }
duke@435 1112
duke@435 1113 size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up(
duke@435 1114 size_t cur_promo) {
duke@435 1115 size_t result = promo_increment(cur_promo,
duke@435 1116 TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement);
jwilhelm@6085 1117 return align_size_up(result, _space_alignment);
duke@435 1118 }
duke@435 1119
duke@435 1120 size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
duke@435 1121 size_t promo_heap_delta = promo_decrement(cur_promo);
jwilhelm@6085 1122 return align_size_down(promo_heap_delta, _space_alignment);
duke@435 1123 }
duke@435 1124
duke@435 1125 size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
duke@435 1126 size_t promo_heap_delta = promo_increment(cur_promo);
duke@435 1127 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
duke@435 1128 return promo_heap_delta;
duke@435 1129 }
duke@435 1130
jwilhelm@4129 1131 uint PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
duke@435 1132 bool is_survivor_overflow,
jwilhelm@4129 1133 uint tenuring_threshold,
duke@435 1134 size_t survivor_limit) {
jwilhelm@6085 1135 assert(survivor_limit >= _space_alignment,
duke@435 1136 "survivor_limit too small");
jwilhelm@6085 1137 assert((size_t)align_size_down(survivor_limit, _space_alignment)
duke@435 1138 == survivor_limit, "survivor_limit not aligned");
duke@435 1139
duke@435 1140 // This method is called even if the tenuring threshold and survivor
duke@435 1141 // spaces are not adjusted so that the averages are sampled above.
duke@435 1142 if (!UsePSAdaptiveSurvivorSizePolicy ||
duke@435 1143 !young_gen_policy_is_ready()) {
duke@435 1144 return tenuring_threshold;
duke@435 1145 }
duke@435 1146
duke@435 1147 // We'll decide whether to increase or decrease the tenuring
duke@435 1148 // threshold based partly on the newly computed survivor size
duke@435 1149 // (if we hit the maximum limit allowed, we'll always choose to
duke@435 1150 // decrement the threshold).
duke@435 1151 bool incr_tenuring_threshold = false;
duke@435 1152 bool decr_tenuring_threshold = false;
duke@435 1153
duke@435 1154 set_decrement_tenuring_threshold_for_gc_cost(false);
duke@435 1155 set_increment_tenuring_threshold_for_gc_cost(false);
duke@435 1156 set_decrement_tenuring_threshold_for_survivor_limit(false);
duke@435 1157
duke@435 1158 if (!is_survivor_overflow) {
duke@435 1159 // Keep running averages on how much survived
duke@435 1160
duke@435 1161 // We use the tenuring threshold to equalize the cost of major
duke@435 1162 // and minor collections.
duke@435 1163 // ThresholdTolerance is used to indicate how sensitive the
duke@435 1164 // tenuring threshold is to differences in cost betweent the
duke@435 1165 // collection types.
duke@435 1166
duke@435 1167 // Get the times of interest. This involves a little work, so
duke@435 1168 // we cache the values here.
duke@435 1169 const double major_cost = major_gc_cost();
duke@435 1170 const double minor_cost = minor_gc_cost();
duke@435 1171
duke@435 1172 if (minor_cost > major_cost * _threshold_tolerance_percent) {
duke@435 1173 // Minor times are getting too long; lower the threshold so
duke@435 1174 // less survives and more is promoted.
duke@435 1175 decr_tenuring_threshold = true;
duke@435 1176 set_decrement_tenuring_threshold_for_gc_cost(true);
duke@435 1177 } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
duke@435 1178 // Major times are too long, so we want less promotion.
duke@435 1179 incr_tenuring_threshold = true;
duke@435 1180 set_increment_tenuring_threshold_for_gc_cost(true);
duke@435 1181 }
duke@435 1182
duke@435 1183 } else {
duke@435 1184 // Survivor space overflow occurred, so promoted and survived are
duke@435 1185 // not accurate. We'll make our best guess by combining survived
duke@435 1186 // and promoted and count them as survivors.
duke@435 1187 //
duke@435 1188 // We'll lower the tenuring threshold to see if we can correct
duke@435 1189 // things. Also, set the survivor size conservatively. We're
duke@435 1190 // trying to avoid many overflows from occurring if defnew size
duke@435 1191 // is just too small.
duke@435 1192
duke@435 1193 decr_tenuring_threshold = true;
duke@435 1194 }
duke@435 1195
duke@435 1196 // The padded average also maintains a deviation from the average;
duke@435 1197 // we use this to see how good of an estimate we have of what survived.
duke@435 1198 // We're trying to pad the survivor size as little as possible without
duke@435 1199 // overflowing the survivor spaces.
duke@435 1200 size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
jwilhelm@6085 1201 _space_alignment);
jwilhelm@6085 1202 target_size = MAX2(target_size, _space_alignment);
duke@435 1203
duke@435 1204 if (target_size > survivor_limit) {
duke@435 1205 // Target size is bigger than we can handle. Let's also reduce
duke@435 1206 // the tenuring threshold.
duke@435 1207 target_size = survivor_limit;
duke@435 1208 decr_tenuring_threshold = true;
duke@435 1209 set_decrement_tenuring_threshold_for_survivor_limit(true);
duke@435 1210 }
duke@435 1211
duke@435 1212 // Finally, increment or decrement the tenuring threshold, as decided above.
duke@435 1213 // We test for decrementing first, as we might have hit the target size
duke@435 1214 // limit.
duke@435 1215 if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
duke@435 1216 if (tenuring_threshold > 1) {
duke@435 1217 tenuring_threshold--;
duke@435 1218 }
duke@435 1219 } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
duke@435 1220 if (tenuring_threshold < MaxTenuringThreshold) {
duke@435 1221 tenuring_threshold++;
duke@435 1222 }
duke@435 1223 }
duke@435 1224
duke@435 1225 // We keep a running average of the amount promoted which is used
duke@435 1226 // to decide when we should collect the old generation (when
duke@435 1227 // the amount of old gen free space is less than what we expect to
duke@435 1228 // promote).
duke@435 1229
duke@435 1230 if (PrintAdaptiveSizePolicy) {
duke@435 1231 // A little more detail if Verbose is on
duke@435 1232 if (Verbose) {
duke@435 1233 gclog_or_tty->print( " avg_survived: %f"
duke@435 1234 " avg_deviation: %f",
duke@435 1235 _avg_survived->average(),
duke@435 1236 _avg_survived->deviation());
duke@435 1237 }
duke@435 1238
duke@435 1239 gclog_or_tty->print( " avg_survived_padded_avg: %f",
duke@435 1240 _avg_survived->padded_average());
duke@435 1241
duke@435 1242 if (Verbose) {
duke@435 1243 gclog_or_tty->print( " avg_promoted_avg: %f"
duke@435 1244 " avg_promoted_dev: %f",
duke@435 1245 avg_promoted()->average(),
duke@435 1246 avg_promoted()->deviation());
duke@435 1247 }
duke@435 1248
poonam@5279 1249 gclog_or_tty->print_cr( " avg_promoted_padded_avg: %f"
duke@435 1250 " avg_pretenured_padded_avg: %f"
duke@435 1251 " tenuring_thresh: %d"
duke@435 1252 " target_size: " SIZE_FORMAT,
duke@435 1253 avg_promoted()->padded_average(),
duke@435 1254 _avg_pretenured->padded_average(),
duke@435 1255 tenuring_threshold, target_size);
duke@435 1256 }
duke@435 1257
duke@435 1258 set_survivor_size(target_size);
duke@435 1259
duke@435 1260 return tenuring_threshold;
duke@435 1261 }
duke@435 1262
duke@435 1263 void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow,
duke@435 1264 size_t survived,
duke@435 1265 size_t promoted) {
duke@435 1266 // Update averages
duke@435 1267 if (!is_survivor_overflow) {
duke@435 1268 // Keep running averages on how much survived
duke@435 1269 _avg_survived->sample(survived);
duke@435 1270 } else {
duke@435 1271 size_t survived_guess = survived + promoted;
duke@435 1272 _avg_survived->sample(survived_guess);
duke@435 1273 }
duke@435 1274 avg_promoted()->sample(promoted + _avg_pretenured->padded_average());
duke@435 1275
duke@435 1276 if (PrintAdaptiveSizePolicy) {
poonam@5279 1277 gclog_or_tty->print_cr(
tamao@5192 1278 "AdaptiveSizePolicy::update_averages:"
duke@435 1279 " survived: " SIZE_FORMAT
duke@435 1280 " promoted: " SIZE_FORMAT
duke@435 1281 " overflow: %s",
duke@435 1282 survived, promoted, is_survivor_overflow ? "true" : "false");
duke@435 1283 }
duke@435 1284 }
duke@435 1285
duke@435 1286 bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st)
duke@435 1287 const {
duke@435 1288
duke@435 1289 if (!UseAdaptiveSizePolicy) return false;
duke@435 1290
duke@435 1291 return AdaptiveSizePolicy::print_adaptive_size_policy_on(
duke@435 1292 st,
duke@435 1293 PSScavenge::tenuring_threshold());
duke@435 1294 }

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