1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,1344 @@
1.4 +/*
1.5 + * Copyright (c) 2002, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
1.30 +#include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
1.31 +#include "gc_implementation/parallelScavenge/psGCAdaptivePolicyCounters.hpp"
1.32 +#include "gc_implementation/parallelScavenge/psScavenge.hpp"
1.33 +#include "gc_implementation/shared/gcPolicyCounters.hpp"
1.34 +#include "gc_interface/gcCause.hpp"
1.35 +#include "memory/collectorPolicy.hpp"
1.36 +#include "runtime/timer.hpp"
1.37 +#include "utilities/top.hpp"
1.38 +
1.39 +#include <math.h>
1.40 +
1.41 +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
1.42 +
1.43 +PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size,
1.44 + size_t init_promo_size,
1.45 + size_t init_survivor_size,
1.46 + size_t space_alignment,
1.47 + double gc_pause_goal_sec,
1.48 + double gc_minor_pause_goal_sec,
1.49 + uint gc_cost_ratio) :
1.50 + AdaptiveSizePolicy(init_eden_size,
1.51 + init_promo_size,
1.52 + init_survivor_size,
1.53 + gc_pause_goal_sec,
1.54 + gc_cost_ratio),
1.55 + _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin / 100.0),
1.56 + _space_alignment(space_alignment),
1.57 + _live_at_last_full_gc(init_promo_size),
1.58 + _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec),
1.59 + _latest_major_mutator_interval_seconds(0),
1.60 + _young_gen_change_for_major_pause_count(0)
1.61 +{
1.62 + // Sizing policy statistics
1.63 + _avg_major_pause =
1.64 + new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
1.65 + _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
1.66 + _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
1.67 +
1.68 + _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
1.69 + _major_pause_old_estimator =
1.70 + new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
1.71 + _major_pause_young_estimator =
1.72 + new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
1.73 + _major_collection_estimator =
1.74 + new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
1.75 +
1.76 + _young_gen_size_increment_supplement = YoungGenerationSizeSupplement;
1.77 + _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement;
1.78 +
1.79 + // Start the timers
1.80 + _major_timer.start();
1.81 +
1.82 + _old_gen_policy_is_ready = false;
1.83 +}
1.84 +
1.85 +size_t PSAdaptiveSizePolicy::calculate_free_based_on_live(size_t live, uintx ratio_as_percentage) {
1.86 + // We want to calculate how much free memory there can be based on the
1.87 + // amount of live data currently in the old gen. Using the formula:
1.88 + // ratio * (free + live) = free
1.89 + // Some equation solving later we get:
1.90 + // free = (live * ratio) / (1 - ratio)
1.91 +
1.92 + const double ratio = ratio_as_percentage / 100.0;
1.93 + const double ratio_inverse = 1.0 - ratio;
1.94 + const double tmp = live * ratio;
1.95 + size_t free = (size_t)(tmp / ratio_inverse);
1.96 +
1.97 + return free;
1.98 +}
1.99 +
1.100 +size_t PSAdaptiveSizePolicy::calculated_old_free_size_in_bytes() const {
1.101 + size_t free_size = (size_t)(_promo_size + avg_promoted()->padded_average());
1.102 + size_t live = ParallelScavengeHeap::heap()->old_gen()->used_in_bytes();
1.103 +
1.104 + if (MinHeapFreeRatio != 0) {
1.105 + size_t min_free = calculate_free_based_on_live(live, MinHeapFreeRatio);
1.106 + free_size = MAX2(free_size, min_free);
1.107 + }
1.108 +
1.109 + if (MaxHeapFreeRatio != 100) {
1.110 + size_t max_free = calculate_free_based_on_live(live, MaxHeapFreeRatio);
1.111 + free_size = MIN2(max_free, free_size);
1.112 + }
1.113 +
1.114 + return free_size;
1.115 +}
1.116 +
1.117 +void PSAdaptiveSizePolicy::major_collection_begin() {
1.118 + // Update the interval time
1.119 + _major_timer.stop();
1.120 + // Save most recent collection time
1.121 + _latest_major_mutator_interval_seconds = _major_timer.seconds();
1.122 + _major_timer.reset();
1.123 + _major_timer.start();
1.124 +}
1.125 +
1.126 +void PSAdaptiveSizePolicy::update_minor_pause_old_estimator(
1.127 + double minor_pause_in_ms) {
1.128 + double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
1.129 + _minor_pause_old_estimator->update(promo_size_in_mbytes,
1.130 + minor_pause_in_ms);
1.131 +}
1.132 +
1.133 +void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live,
1.134 + GCCause::Cause gc_cause) {
1.135 + // Update the pause time.
1.136 + _major_timer.stop();
1.137 +
1.138 + if (gc_cause != GCCause::_java_lang_system_gc ||
1.139 + UseAdaptiveSizePolicyWithSystemGC) {
1.140 + double major_pause_in_seconds = _major_timer.seconds();
1.141 + double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS;
1.142 +
1.143 + // Sample for performance counter
1.144 + _avg_major_pause->sample(major_pause_in_seconds);
1.145 +
1.146 + // Cost of collection (unit-less)
1.147 + double collection_cost = 0.0;
1.148 + if ((_latest_major_mutator_interval_seconds > 0.0) &&
1.149 + (major_pause_in_seconds > 0.0)) {
1.150 + double interval_in_seconds =
1.151 + _latest_major_mutator_interval_seconds + major_pause_in_seconds;
1.152 + collection_cost =
1.153 + major_pause_in_seconds / interval_in_seconds;
1.154 + avg_major_gc_cost()->sample(collection_cost);
1.155 +
1.156 + // Sample for performance counter
1.157 + _avg_major_interval->sample(interval_in_seconds);
1.158 + }
1.159 +
1.160 + // Calculate variables used to estimate pause time vs. gen sizes
1.161 + double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
1.162 + double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
1.163 + _major_pause_old_estimator->update(promo_size_in_mbytes,
1.164 + major_pause_in_ms);
1.165 + _major_pause_young_estimator->update(eden_size_in_mbytes,
1.166 + major_pause_in_ms);
1.167 +
1.168 + if (PrintAdaptiveSizePolicy && Verbose) {
1.169 + gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: "
1.170 + "major gc cost: %f average: %f", collection_cost,
1.171 + avg_major_gc_cost()->average());
1.172 + gclog_or_tty->print_cr(" major pause: %f major period %f",
1.173 + major_pause_in_ms,
1.174 + _latest_major_mutator_interval_seconds * MILLIUNITS);
1.175 + }
1.176 +
1.177 + // Calculate variable used to estimate collection cost vs. gen sizes
1.178 + assert(collection_cost >= 0.0, "Expected to be non-negative");
1.179 + _major_collection_estimator->update(promo_size_in_mbytes,
1.180 + collection_cost);
1.181 + }
1.182 +
1.183 + // Update the amount live at the end of a full GC
1.184 + _live_at_last_full_gc = amount_live;
1.185 +
1.186 + // The policy does not have enough data until at least some major collections
1.187 + // have been done.
1.188 + if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) {
1.189 + _old_gen_policy_is_ready = true;
1.190 + }
1.191 +
1.192 + // Interval times use this timer to measure the interval that
1.193 + // the mutator runs. Reset after the GC pause has been measured.
1.194 + _major_timer.reset();
1.195 + _major_timer.start();
1.196 +}
1.197 +
1.198 +// If the remaining free space in the old generation is less that
1.199 +// that expected to be needed by the next collection, do a full
1.200 +// collection now.
1.201 +bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) {
1.202 +
1.203 + // A similar test is done in the scavenge's should_attempt_scavenge(). If
1.204 + // this is changed, decide if that test should also be changed.
1.205 + bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes;
1.206 + if (PrintGCDetails && Verbose) {
1.207 + if (result) {
1.208 + gclog_or_tty->print(" full after scavenge: ");
1.209 + } else {
1.210 + gclog_or_tty->print(" no full after scavenge: ");
1.211 + }
1.212 + gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
1.213 + " padded_average_promoted " SIZE_FORMAT
1.214 + " free in old gen " SIZE_FORMAT,
1.215 + (size_t) average_promoted_in_bytes(),
1.216 + (size_t) padded_average_promoted_in_bytes(),
1.217 + old_free_in_bytes);
1.218 + }
1.219 + return result;
1.220 +}
1.221 +
1.222 +void PSAdaptiveSizePolicy::clear_generation_free_space_flags() {
1.223 +
1.224 + AdaptiveSizePolicy::clear_generation_free_space_flags();
1.225 +
1.226 + set_change_old_gen_for_min_pauses(0);
1.227 +
1.228 + set_change_young_gen_for_maj_pauses(0);
1.229 +}
1.230 +
1.231 +// If this is not a full GC, only test and modify the young generation.
1.232 +
1.233 +void PSAdaptiveSizePolicy::compute_generations_free_space(
1.234 + size_t young_live,
1.235 + size_t eden_live,
1.236 + size_t old_live,
1.237 + size_t cur_eden,
1.238 + size_t max_old_gen_size,
1.239 + size_t max_eden_size,
1.240 + bool is_full_gc) {
1.241 + compute_eden_space_size(young_live,
1.242 + eden_live,
1.243 + cur_eden,
1.244 + max_eden_size,
1.245 + is_full_gc);
1.246 +
1.247 + compute_old_gen_free_space(old_live,
1.248 + cur_eden,
1.249 + max_old_gen_size,
1.250 + is_full_gc);
1.251 +}
1.252 +
1.253 +void PSAdaptiveSizePolicy::compute_eden_space_size(
1.254 + size_t young_live,
1.255 + size_t eden_live,
1.256 + size_t cur_eden,
1.257 + size_t max_eden_size,
1.258 + bool is_full_gc) {
1.259 +
1.260 + // Update statistics
1.261 + // Time statistics are updated as we go, update footprint stats here
1.262 + _avg_base_footprint->sample(BaseFootPrintEstimate);
1.263 + avg_young_live()->sample(young_live);
1.264 + avg_eden_live()->sample(eden_live);
1.265 +
1.266 + // This code used to return if the policy was not ready , i.e.,
1.267 + // policy_is_ready() returning false. The intent was that
1.268 + // decisions below needed major collection times and so could
1.269 + // not be made before two major collections. A consequence was
1.270 + // adjustments to the young generation were not done until after
1.271 + // two major collections even if the minor collections times
1.272 + // exceeded the requested goals. Now let the young generation
1.273 + // adjust for the minor collection times. Major collection times
1.274 + // will be zero for the first collection and will naturally be
1.275 + // ignored. Tenured generation adjustments are only made at the
1.276 + // full collections so until the second major collection has
1.277 + // been reached, no tenured generation adjustments will be made.
1.278 +
1.279 + // Until we know better, desired promotion size uses the last calculation
1.280 + size_t desired_promo_size = _promo_size;
1.281 +
1.282 + // Start eden at the current value. The desired value that is stored
1.283 + // in _eden_size is not bounded by constraints of the heap and can
1.284 + // run away.
1.285 + //
1.286 + // As expected setting desired_eden_size to the current
1.287 + // value of desired_eden_size as a starting point
1.288 + // caused desired_eden_size to grow way too large and caused
1.289 + // an overflow down stream. It may have improved performance in
1.290 + // some case but is dangerous.
1.291 + size_t desired_eden_size = cur_eden;
1.292 +
1.293 + // Cache some values. There's a bit of work getting these, so
1.294 + // we might save a little time.
1.295 + const double major_cost = major_gc_cost();
1.296 + const double minor_cost = minor_gc_cost();
1.297 +
1.298 + // This method sets the desired eden size. That plus the
1.299 + // desired survivor space sizes sets the desired young generation
1.300 + // size. This methods does not know what the desired survivor
1.301 + // size is but expects that other policy will attempt to make
1.302 + // the survivor sizes compatible with the live data in the
1.303 + // young generation. This limit is an estimate of the space left
1.304 + // in the young generation after the survivor spaces have been
1.305 + // subtracted out.
1.306 + size_t eden_limit = max_eden_size;
1.307 +
1.308 + const double gc_cost_limit = GCTimeLimit/100.0;
1.309 +
1.310 + // Which way should we go?
1.311 + // if pause requirement is not met
1.312 + // adjust size of any generation with average paus exceeding
1.313 + // the pause limit. Adjust one pause at a time (the larger)
1.314 + // and only make adjustments for the major pause at full collections.
1.315 + // else if throughput requirement not met
1.316 + // adjust the size of the generation with larger gc time. Only
1.317 + // adjust one generation at a time.
1.318 + // else
1.319 + // adjust down the total heap size. Adjust down the larger of the
1.320 + // generations.
1.321 +
1.322 + // Add some checks for a threshold for a change. For example,
1.323 + // a change less than the necessary alignment is probably not worth
1.324 + // attempting.
1.325 +
1.326 +
1.327 + if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
1.328 + (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
1.329 + //
1.330 + // Check pauses
1.331 + //
1.332 + // Make changes only to affect one of the pauses (the larger)
1.333 + // at a time.
1.334 + adjust_eden_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
1.335 +
1.336 + } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
1.337 + // Adjust only for the minor pause time goal
1.338 + adjust_eden_for_minor_pause_time(is_full_gc, &desired_eden_size);
1.339 +
1.340 + } else if(adjusted_mutator_cost() < _throughput_goal) {
1.341 + // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
1.342 + // This sometimes resulted in skipping to the minimize footprint
1.343 + // code. Change this to try and reduce GC time if mutator time is
1.344 + // negative for whatever reason. Or for future consideration,
1.345 + // bail out of the code if mutator time is negative.
1.346 + //
1.347 + // Throughput
1.348 + //
1.349 + assert(major_cost >= 0.0, "major cost is < 0.0");
1.350 + assert(minor_cost >= 0.0, "minor cost is < 0.0");
1.351 + // Try to reduce the GC times.
1.352 + adjust_eden_for_throughput(is_full_gc, &desired_eden_size);
1.353 +
1.354 + } else {
1.355 +
1.356 + // Be conservative about reducing the footprint.
1.357 + // Do a minimum number of major collections first.
1.358 + // Have reasonable averages for major and minor collections costs.
1.359 + if (UseAdaptiveSizePolicyFootprintGoal &&
1.360 + young_gen_policy_is_ready() &&
1.361 + avg_major_gc_cost()->average() >= 0.0 &&
1.362 + avg_minor_gc_cost()->average() >= 0.0) {
1.363 + size_t desired_sum = desired_eden_size + desired_promo_size;
1.364 + desired_eden_size = adjust_eden_for_footprint(desired_eden_size, desired_sum);
1.365 + }
1.366 + }
1.367 +
1.368 + // Note we make the same tests as in the code block below; the code
1.369 + // seems a little easier to read with the printing in another block.
1.370 + if (PrintAdaptiveSizePolicy) {
1.371 + if (desired_eden_size > eden_limit) {
1.372 + gclog_or_tty->print_cr(
1.373 + "PSAdaptiveSizePolicy::compute_eden_space_size limits:"
1.374 + " desired_eden_size: " SIZE_FORMAT
1.375 + " old_eden_size: " SIZE_FORMAT
1.376 + " eden_limit: " SIZE_FORMAT
1.377 + " cur_eden: " SIZE_FORMAT
1.378 + " max_eden_size: " SIZE_FORMAT
1.379 + " avg_young_live: " SIZE_FORMAT,
1.380 + desired_eden_size, _eden_size, eden_limit, cur_eden,
1.381 + max_eden_size, (size_t)avg_young_live()->average());
1.382 + }
1.383 + if (gc_cost() > gc_cost_limit) {
1.384 + gclog_or_tty->print_cr(
1.385 + "PSAdaptiveSizePolicy::compute_eden_space_size: gc time limit"
1.386 + " gc_cost: %f "
1.387 + " GCTimeLimit: %d",
1.388 + gc_cost(), GCTimeLimit);
1.389 + }
1.390 + }
1.391 +
1.392 + // Align everything and make a final limit check
1.393 + desired_eden_size = align_size_up(desired_eden_size, _space_alignment);
1.394 + desired_eden_size = MAX2(desired_eden_size, _space_alignment);
1.395 +
1.396 + eden_limit = align_size_down(eden_limit, _space_alignment);
1.397 +
1.398 + // And one last limit check, now that we've aligned things.
1.399 + if (desired_eden_size > eden_limit) {
1.400 + // If the policy says to get a larger eden but
1.401 + // is hitting the limit, don't decrease eden.
1.402 + // This can lead to a general drifting down of the
1.403 + // eden size. Let the tenuring calculation push more
1.404 + // into the old gen.
1.405 + desired_eden_size = MAX2(eden_limit, cur_eden);
1.406 + }
1.407 +
1.408 + if (PrintAdaptiveSizePolicy) {
1.409 + // Timing stats
1.410 + gclog_or_tty->print(
1.411 + "PSAdaptiveSizePolicy::compute_eden_space_size: costs"
1.412 + " minor_time: %f"
1.413 + " major_cost: %f"
1.414 + " mutator_cost: %f"
1.415 + " throughput_goal: %f",
1.416 + minor_gc_cost(), major_gc_cost(), mutator_cost(),
1.417 + _throughput_goal);
1.418 +
1.419 + // We give more details if Verbose is set
1.420 + if (Verbose) {
1.421 + gclog_or_tty->print( " minor_pause: %f"
1.422 + " major_pause: %f"
1.423 + " minor_interval: %f"
1.424 + " major_interval: %f"
1.425 + " pause_goal: %f",
1.426 + _avg_minor_pause->padded_average(),
1.427 + _avg_major_pause->padded_average(),
1.428 + _avg_minor_interval->average(),
1.429 + _avg_major_interval->average(),
1.430 + gc_pause_goal_sec());
1.431 + }
1.432 +
1.433 + // Footprint stats
1.434 + gclog_or_tty->print( " live_space: " SIZE_FORMAT
1.435 + " free_space: " SIZE_FORMAT,
1.436 + live_space(), free_space());
1.437 + // More detail
1.438 + if (Verbose) {
1.439 + gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
1.440 + " avg_young_live: " SIZE_FORMAT
1.441 + " avg_old_live: " SIZE_FORMAT,
1.442 + (size_t)_avg_base_footprint->average(),
1.443 + (size_t)avg_young_live()->average(),
1.444 + (size_t)avg_old_live()->average());
1.445 + }
1.446 +
1.447 + // And finally, our old and new sizes.
1.448 + gclog_or_tty->print(" old_eden_size: " SIZE_FORMAT
1.449 + " desired_eden_size: " SIZE_FORMAT,
1.450 + _eden_size, desired_eden_size);
1.451 + gclog_or_tty->cr();
1.452 + }
1.453 +
1.454 + set_eden_size(desired_eden_size);
1.455 +}
1.456 +
1.457 +void PSAdaptiveSizePolicy::compute_old_gen_free_space(
1.458 + size_t old_live,
1.459 + size_t cur_eden,
1.460 + size_t max_old_gen_size,
1.461 + bool is_full_gc) {
1.462 +
1.463 + // Update statistics
1.464 + // Time statistics are updated as we go, update footprint stats here
1.465 + if (is_full_gc) {
1.466 + // old_live is only accurate after a full gc
1.467 + avg_old_live()->sample(old_live);
1.468 + }
1.469 +
1.470 + // This code used to return if the policy was not ready , i.e.,
1.471 + // policy_is_ready() returning false. The intent was that
1.472 + // decisions below needed major collection times and so could
1.473 + // not be made before two major collections. A consequence was
1.474 + // adjustments to the young generation were not done until after
1.475 + // two major collections even if the minor collections times
1.476 + // exceeded the requested goals. Now let the young generation
1.477 + // adjust for the minor collection times. Major collection times
1.478 + // will be zero for the first collection and will naturally be
1.479 + // ignored. Tenured generation adjustments are only made at the
1.480 + // full collections so until the second major collection has
1.481 + // been reached, no tenured generation adjustments will be made.
1.482 +
1.483 + // Until we know better, desired promotion size uses the last calculation
1.484 + size_t desired_promo_size = _promo_size;
1.485 +
1.486 + // Start eden at the current value. The desired value that is stored
1.487 + // in _eden_size is not bounded by constraints of the heap and can
1.488 + // run away.
1.489 + //
1.490 + // As expected setting desired_eden_size to the current
1.491 + // value of desired_eden_size as a starting point
1.492 + // caused desired_eden_size to grow way too large and caused
1.493 + // an overflow down stream. It may have improved performance in
1.494 + // some case but is dangerous.
1.495 + size_t desired_eden_size = cur_eden;
1.496 +
1.497 + // Cache some values. There's a bit of work getting these, so
1.498 + // we might save a little time.
1.499 + const double major_cost = major_gc_cost();
1.500 + const double minor_cost = minor_gc_cost();
1.501 +
1.502 + // Limits on our growth
1.503 + size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
1.504 +
1.505 + // But don't force a promo size below the current promo size. Otherwise,
1.506 + // the promo size will shrink for no good reason.
1.507 + promo_limit = MAX2(promo_limit, _promo_size);
1.508 +
1.509 + const double gc_cost_limit = GCTimeLimit/100.0;
1.510 +
1.511 + // Which way should we go?
1.512 + // if pause requirement is not met
1.513 + // adjust size of any generation with average paus exceeding
1.514 + // the pause limit. Adjust one pause at a time (the larger)
1.515 + // and only make adjustments for the major pause at full collections.
1.516 + // else if throughput requirement not met
1.517 + // adjust the size of the generation with larger gc time. Only
1.518 + // adjust one generation at a time.
1.519 + // else
1.520 + // adjust down the total heap size. Adjust down the larger of the
1.521 + // generations.
1.522 +
1.523 + // Add some checks for a threshhold for a change. For example,
1.524 + // a change less than the necessary alignment is probably not worth
1.525 + // attempting.
1.526 +
1.527 + if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
1.528 + (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
1.529 + //
1.530 + // Check pauses
1.531 + //
1.532 + // Make changes only to affect one of the pauses (the larger)
1.533 + // at a time.
1.534 + if (is_full_gc) {
1.535 + set_decide_at_full_gc(decide_at_full_gc_true);
1.536 + adjust_promo_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
1.537 + }
1.538 + } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
1.539 + // Adjust only for the minor pause time goal
1.540 + adjust_promo_for_minor_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
1.541 + } else if(adjusted_mutator_cost() < _throughput_goal) {
1.542 + // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
1.543 + // This sometimes resulted in skipping to the minimize footprint
1.544 + // code. Change this to try and reduce GC time if mutator time is
1.545 + // negative for whatever reason. Or for future consideration,
1.546 + // bail out of the code if mutator time is negative.
1.547 + //
1.548 + // Throughput
1.549 + //
1.550 + assert(major_cost >= 0.0, "major cost is < 0.0");
1.551 + assert(minor_cost >= 0.0, "minor cost is < 0.0");
1.552 + // Try to reduce the GC times.
1.553 + if (is_full_gc) {
1.554 + set_decide_at_full_gc(decide_at_full_gc_true);
1.555 + adjust_promo_for_throughput(is_full_gc, &desired_promo_size);
1.556 + }
1.557 + } else {
1.558 +
1.559 + // Be conservative about reducing the footprint.
1.560 + // Do a minimum number of major collections first.
1.561 + // Have reasonable averages for major and minor collections costs.
1.562 + if (UseAdaptiveSizePolicyFootprintGoal &&
1.563 + young_gen_policy_is_ready() &&
1.564 + avg_major_gc_cost()->average() >= 0.0 &&
1.565 + avg_minor_gc_cost()->average() >= 0.0) {
1.566 + if (is_full_gc) {
1.567 + set_decide_at_full_gc(decide_at_full_gc_true);
1.568 + size_t desired_sum = desired_eden_size + desired_promo_size;
1.569 + desired_promo_size = adjust_promo_for_footprint(desired_promo_size, desired_sum);
1.570 + }
1.571 + }
1.572 + }
1.573 +
1.574 + // Note we make the same tests as in the code block below; the code
1.575 + // seems a little easier to read with the printing in another block.
1.576 + if (PrintAdaptiveSizePolicy) {
1.577 + if (desired_promo_size > promo_limit) {
1.578 + // "free_in_old_gen" was the original value for used for promo_limit
1.579 + size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
1.580 + gclog_or_tty->print_cr(
1.581 + "PSAdaptiveSizePolicy::compute_old_gen_free_space limits:"
1.582 + " desired_promo_size: " SIZE_FORMAT
1.583 + " promo_limit: " SIZE_FORMAT
1.584 + " free_in_old_gen: " SIZE_FORMAT
1.585 + " max_old_gen_size: " SIZE_FORMAT
1.586 + " avg_old_live: " SIZE_FORMAT,
1.587 + desired_promo_size, promo_limit, free_in_old_gen,
1.588 + max_old_gen_size, (size_t) avg_old_live()->average());
1.589 + }
1.590 + if (gc_cost() > gc_cost_limit) {
1.591 + gclog_or_tty->print_cr(
1.592 + "PSAdaptiveSizePolicy::compute_old_gen_free_space: gc time limit"
1.593 + " gc_cost: %f "
1.594 + " GCTimeLimit: %d",
1.595 + gc_cost(), GCTimeLimit);
1.596 + }
1.597 + }
1.598 +
1.599 + // Align everything and make a final limit check
1.600 + desired_promo_size = align_size_up(desired_promo_size, _space_alignment);
1.601 + desired_promo_size = MAX2(desired_promo_size, _space_alignment);
1.602 +
1.603 + promo_limit = align_size_down(promo_limit, _space_alignment);
1.604 +
1.605 + // And one last limit check, now that we've aligned things.
1.606 + desired_promo_size = MIN2(desired_promo_size, promo_limit);
1.607 +
1.608 + if (PrintAdaptiveSizePolicy) {
1.609 + // Timing stats
1.610 + gclog_or_tty->print(
1.611 + "PSAdaptiveSizePolicy::compute_old_gen_free_space: costs"
1.612 + " minor_time: %f"
1.613 + " major_cost: %f"
1.614 + " mutator_cost: %f"
1.615 + " throughput_goal: %f",
1.616 + minor_gc_cost(), major_gc_cost(), mutator_cost(),
1.617 + _throughput_goal);
1.618 +
1.619 + // We give more details if Verbose is set
1.620 + if (Verbose) {
1.621 + gclog_or_tty->print( " minor_pause: %f"
1.622 + " major_pause: %f"
1.623 + " minor_interval: %f"
1.624 + " major_interval: %f"
1.625 + " pause_goal: %f",
1.626 + _avg_minor_pause->padded_average(),
1.627 + _avg_major_pause->padded_average(),
1.628 + _avg_minor_interval->average(),
1.629 + _avg_major_interval->average(),
1.630 + gc_pause_goal_sec());
1.631 + }
1.632 +
1.633 + // Footprint stats
1.634 + gclog_or_tty->print( " live_space: " SIZE_FORMAT
1.635 + " free_space: " SIZE_FORMAT,
1.636 + live_space(), free_space());
1.637 + // More detail
1.638 + if (Verbose) {
1.639 + gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
1.640 + " avg_young_live: " SIZE_FORMAT
1.641 + " avg_old_live: " SIZE_FORMAT,
1.642 + (size_t)_avg_base_footprint->average(),
1.643 + (size_t)avg_young_live()->average(),
1.644 + (size_t)avg_old_live()->average());
1.645 + }
1.646 +
1.647 + // And finally, our old and new sizes.
1.648 + gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT
1.649 + " desired_promo_size: " SIZE_FORMAT,
1.650 + _promo_size, desired_promo_size);
1.651 + gclog_or_tty->cr();
1.652 + }
1.653 +
1.654 + set_promo_size(desired_promo_size);
1.655 +}
1.656 +
1.657 +void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) {
1.658 + // Decay the supplemental increment? Decay the supplement growth
1.659 + // factor even if it is not used. It is only meant to give a boost
1.660 + // to the initial growth and if it is not used, then it was not
1.661 + // needed.
1.662 + if (is_full_gc) {
1.663 + // Don't wait for the threshold value for the major collections. If
1.664 + // here, the supplemental growth term was used and should decay.
1.665 + if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay)
1.666 + == 0) {
1.667 + _old_gen_size_increment_supplement =
1.668 + _old_gen_size_increment_supplement >> 1;
1.669 + }
1.670 + } else {
1.671 + if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) &&
1.672 + (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) {
1.673 + _young_gen_size_increment_supplement =
1.674 + _young_gen_size_increment_supplement >> 1;
1.675 + }
1.676 + }
1.677 +}
1.678 +
1.679 +void PSAdaptiveSizePolicy::adjust_promo_for_minor_pause_time(bool is_full_gc,
1.680 + size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) {
1.681 +
1.682 + if (PSAdjustTenuredGenForMinorPause) {
1.683 + if (is_full_gc) {
1.684 + set_decide_at_full_gc(decide_at_full_gc_true);
1.685 + }
1.686 + // If the desired eden size is as small as it will get,
1.687 + // try to adjust the old gen size.
1.688 + if (*desired_eden_size_ptr <= _space_alignment) {
1.689 + // Vary the old gen size to reduce the young gen pause. This
1.690 + // may not be a good idea. This is just a test.
1.691 + if (minor_pause_old_estimator()->decrement_will_decrease()) {
1.692 + set_change_old_gen_for_min_pauses(decrease_old_gen_for_min_pauses_true);
1.693 + *desired_promo_size_ptr =
1.694 + _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr);
1.695 + } else {
1.696 + set_change_old_gen_for_min_pauses(increase_old_gen_for_min_pauses_true);
1.697 + size_t promo_heap_delta =
1.698 + promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
1.699 + if ((*desired_promo_size_ptr + promo_heap_delta) >
1.700 + *desired_promo_size_ptr) {
1.701 + *desired_promo_size_ptr =
1.702 + _promo_size + promo_heap_delta;
1.703 + }
1.704 + }
1.705 + }
1.706 + }
1.707 +}
1.708 +
1.709 +void PSAdaptiveSizePolicy::adjust_eden_for_minor_pause_time(bool is_full_gc,
1.710 + size_t* desired_eden_size_ptr) {
1.711 +
1.712 + // Adjust the young generation size to reduce pause time of
1.713 + // of collections.
1.714 + //
1.715 + // The AdaptiveSizePolicyInitializingSteps test is not used
1.716 + // here. It has not seemed to be needed but perhaps should
1.717 + // be added for consistency.
1.718 + if (minor_pause_young_estimator()->decrement_will_decrease()) {
1.719 + // reduce eden size
1.720 + set_change_young_gen_for_min_pauses(
1.721 + decrease_young_gen_for_min_pauses_true);
1.722 + *desired_eden_size_ptr = *desired_eden_size_ptr -
1.723 + eden_decrement_aligned_down(*desired_eden_size_ptr);
1.724 + } else {
1.725 + // EXPERIMENTAL ADJUSTMENT
1.726 + // Only record that the estimator indicated such an action.
1.727 + // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta;
1.728 + set_change_young_gen_for_min_pauses(
1.729 + increase_young_gen_for_min_pauses_true);
1.730 + }
1.731 +}
1.732 +
1.733 +void PSAdaptiveSizePolicy::adjust_promo_for_pause_time(bool is_full_gc,
1.734 + size_t* desired_promo_size_ptr,
1.735 + size_t* desired_eden_size_ptr) {
1.736 +
1.737 + size_t promo_heap_delta = 0;
1.738 + // Add some checks for a threshold for a change. For example,
1.739 + // a change less than the required alignment is probably not worth
1.740 + // attempting.
1.741 +
1.742 + if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
1.743 + adjust_promo_for_minor_pause_time(is_full_gc, desired_promo_size_ptr, desired_eden_size_ptr);
1.744 + // major pause adjustments
1.745 + } else if (is_full_gc) {
1.746 + // Adjust for the major pause time only at full gc's because the
1.747 + // affects of a change can only be seen at full gc's.
1.748 +
1.749 + // Reduce old generation size to reduce pause?
1.750 + if (major_pause_old_estimator()->decrement_will_decrease()) {
1.751 + // reduce old generation size
1.752 + set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
1.753 + promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr);
1.754 + *desired_promo_size_ptr = _promo_size - promo_heap_delta;
1.755 + } else {
1.756 + // EXPERIMENTAL ADJUSTMENT
1.757 + // Only record that the estimator indicated such an action.
1.758 + // *desired_promo_size_ptr = _promo_size +
1.759 + // promo_increment_aligned_up(*desired_promo_size_ptr);
1.760 + set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true);
1.761 + }
1.762 + }
1.763 +
1.764 + if (PrintAdaptiveSizePolicy && Verbose) {
1.765 + gclog_or_tty->print_cr(
1.766 + "PSAdaptiveSizePolicy::adjust_promo_for_pause_time "
1.767 + "adjusting gen sizes for major pause (avg %f goal %f). "
1.768 + "desired_promo_size " SIZE_FORMAT " promo delta " SIZE_FORMAT,
1.769 + _avg_major_pause->average(), gc_pause_goal_sec(),
1.770 + *desired_promo_size_ptr, promo_heap_delta);
1.771 + }
1.772 +}
1.773 +
1.774 +void PSAdaptiveSizePolicy::adjust_eden_for_pause_time(bool is_full_gc,
1.775 + size_t* desired_promo_size_ptr,
1.776 + size_t* desired_eden_size_ptr) {
1.777 +
1.778 + size_t eden_heap_delta = 0;
1.779 + // Add some checks for a threshold for a change. For example,
1.780 + // a change less than the required alignment is probably not worth
1.781 + // attempting.
1.782 + if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
1.783 + adjust_eden_for_minor_pause_time(is_full_gc,
1.784 + desired_eden_size_ptr);
1.785 + // major pause adjustments
1.786 + } else if (is_full_gc) {
1.787 + // Adjust for the major pause time only at full gc's because the
1.788 + // affects of a change can only be seen at full gc's.
1.789 + if (PSAdjustYoungGenForMajorPause) {
1.790 + // If the promo size is at the minimum (i.e., the old gen
1.791 + // size will not actually decrease), consider changing the
1.792 + // young gen size.
1.793 + if (*desired_promo_size_ptr < _space_alignment) {
1.794 + // If increasing the young generation will decrease the old gen
1.795 + // pause, do it.
1.796 + // During startup there is noise in the statistics for deciding
1.797 + // on whether to increase or decrease the young gen size. For
1.798 + // some number of iterations, just try to increase the young
1.799 + // gen size if the major pause is too long to try and establish
1.800 + // good statistics for later decisions.
1.801 + if (major_pause_young_estimator()->increment_will_decrease() ||
1.802 + (_young_gen_change_for_major_pause_count
1.803 + <= AdaptiveSizePolicyInitializingSteps)) {
1.804 + set_change_young_gen_for_maj_pauses(
1.805 + increase_young_gen_for_maj_pauses_true);
1.806 + eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr);
1.807 + *desired_eden_size_ptr = _eden_size + eden_heap_delta;
1.808 + _young_gen_change_for_major_pause_count++;
1.809 + } else {
1.810 + // Record that decreasing the young gen size would decrease
1.811 + // the major pause
1.812 + set_change_young_gen_for_maj_pauses(
1.813 + decrease_young_gen_for_maj_pauses_true);
1.814 + eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr);
1.815 + *desired_eden_size_ptr = _eden_size - eden_heap_delta;
1.816 + }
1.817 + }
1.818 + }
1.819 + }
1.820 +
1.821 + if (PrintAdaptiveSizePolicy && Verbose) {
1.822 + gclog_or_tty->print_cr(
1.823 + "PSAdaptiveSizePolicy::adjust_eden_for_pause_time "
1.824 + "adjusting gen sizes for major pause (avg %f goal %f). "
1.825 + "desired_eden_size " SIZE_FORMAT " eden delta " SIZE_FORMAT,
1.826 + _avg_major_pause->average(), gc_pause_goal_sec(),
1.827 + *desired_eden_size_ptr, eden_heap_delta);
1.828 + }
1.829 +}
1.830 +
1.831 +void PSAdaptiveSizePolicy::adjust_promo_for_throughput(bool is_full_gc,
1.832 + size_t* desired_promo_size_ptr) {
1.833 +
1.834 + // Add some checks for a threshold for a change. For example,
1.835 + // a change less than the required alignment is probably not worth
1.836 + // attempting.
1.837 +
1.838 + if ((gc_cost() + mutator_cost()) == 0.0) {
1.839 + return;
1.840 + }
1.841 +
1.842 + if (PrintAdaptiveSizePolicy && Verbose) {
1.843 + gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_promo_for_throughput("
1.844 + "is_full: %d, promo: " SIZE_FORMAT "): ",
1.845 + is_full_gc, *desired_promo_size_ptr);
1.846 + gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
1.847 + "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
1.848 + }
1.849 +
1.850 + // Tenured generation
1.851 + if (is_full_gc) {
1.852 + // Calculate the change to use for the tenured gen.
1.853 + size_t scaled_promo_heap_delta = 0;
1.854 + // Can the increment to the generation be scaled?
1.855 + if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) {
1.856 + size_t promo_heap_delta =
1.857 + promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
1.858 + double scale_by_ratio = major_gc_cost() / gc_cost();
1.859 + scaled_promo_heap_delta =
1.860 + (size_t) (scale_by_ratio * (double) promo_heap_delta);
1.861 + if (PrintAdaptiveSizePolicy && Verbose) {
1.862 + gclog_or_tty->print_cr(
1.863 + "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
1.864 + SIZE_FORMAT,
1.865 + promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta);
1.866 + }
1.867 + } else if (major_gc_cost() >= 0.0) {
1.868 + // Scaling is not going to work. If the major gc time is the
1.869 + // larger, give it a full increment.
1.870 + if (major_gc_cost() >= minor_gc_cost()) {
1.871 + scaled_promo_heap_delta =
1.872 + promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
1.873 + }
1.874 + } else {
1.875 + // Don't expect to get here but it's ok if it does
1.876 + // in the product build since the delta will be 0
1.877 + // and nothing will change.
1.878 + assert(false, "Unexpected value for gc costs");
1.879 + }
1.880 +
1.881 + switch (AdaptiveSizeThroughPutPolicy) {
1.882 + case 1:
1.883 + // Early in the run the statistics might not be good. Until
1.884 + // a specific number of collections have been, use the heuristic
1.885 + // that a larger generation size means lower collection costs.
1.886 + if (major_collection_estimator()->increment_will_decrease() ||
1.887 + (_old_gen_change_for_major_throughput
1.888 + <= AdaptiveSizePolicyInitializingSteps)) {
1.889 + // Increase tenured generation size to reduce major collection cost
1.890 + if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
1.891 + *desired_promo_size_ptr) {
1.892 + *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta;
1.893 + }
1.894 + set_change_old_gen_for_throughput(
1.895 + increase_old_gen_for_throughput_true);
1.896 + _old_gen_change_for_major_throughput++;
1.897 + } else {
1.898 + // EXPERIMENTAL ADJUSTMENT
1.899 + // Record that decreasing the old gen size would decrease
1.900 + // the major collection cost but don't do it.
1.901 + // *desired_promo_size_ptr = _promo_size -
1.902 + // promo_decrement_aligned_down(*desired_promo_size_ptr);
1.903 + set_change_old_gen_for_throughput(
1.904 + decrease_old_gen_for_throughput_true);
1.905 + }
1.906 +
1.907 + break;
1.908 + default:
1.909 + // Simplest strategy
1.910 + if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
1.911 + *desired_promo_size_ptr) {
1.912 + *desired_promo_size_ptr = *desired_promo_size_ptr +
1.913 + scaled_promo_heap_delta;
1.914 + }
1.915 + set_change_old_gen_for_throughput(
1.916 + increase_old_gen_for_throughput_true);
1.917 + _old_gen_change_for_major_throughput++;
1.918 + }
1.919 +
1.920 + if (PrintAdaptiveSizePolicy && Verbose) {
1.921 + gclog_or_tty->print_cr(
1.922 + "adjusting tenured gen for throughput (avg %f goal %f). "
1.923 + "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT ,
1.924 + mutator_cost(), _throughput_goal,
1.925 + *desired_promo_size_ptr, scaled_promo_heap_delta);
1.926 + }
1.927 + }
1.928 +}
1.929 +
1.930 +void PSAdaptiveSizePolicy::adjust_eden_for_throughput(bool is_full_gc,
1.931 + size_t* desired_eden_size_ptr) {
1.932 +
1.933 + // Add some checks for a threshold for a change. For example,
1.934 + // a change less than the required alignment is probably not worth
1.935 + // attempting.
1.936 +
1.937 + if ((gc_cost() + mutator_cost()) == 0.0) {
1.938 + return;
1.939 + }
1.940 +
1.941 + if (PrintAdaptiveSizePolicy && Verbose) {
1.942 + gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_eden_for_throughput("
1.943 + "is_full: %d, cur_eden: " SIZE_FORMAT "): ",
1.944 + is_full_gc, *desired_eden_size_ptr);
1.945 + gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
1.946 + "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
1.947 + }
1.948 +
1.949 + // Young generation
1.950 + size_t scaled_eden_heap_delta = 0;
1.951 + // Can the increment to the generation be scaled?
1.952 + if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) {
1.953 + size_t eden_heap_delta =
1.954 + eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
1.955 + double scale_by_ratio = minor_gc_cost() / gc_cost();
1.956 + assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong");
1.957 + scaled_eden_heap_delta =
1.958 + (size_t) (scale_by_ratio * (double) eden_heap_delta);
1.959 + if (PrintAdaptiveSizePolicy && Verbose) {
1.960 + gclog_or_tty->print_cr(
1.961 + "Scaled eden increment: " SIZE_FORMAT " by %f down to "
1.962 + SIZE_FORMAT,
1.963 + eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta);
1.964 + }
1.965 + } else if (minor_gc_cost() >= 0.0) {
1.966 + // Scaling is not going to work. If the minor gc time is the
1.967 + // larger, give it a full increment.
1.968 + if (minor_gc_cost() > major_gc_cost()) {
1.969 + scaled_eden_heap_delta =
1.970 + eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
1.971 + }
1.972 + } else {
1.973 + // Don't expect to get here but it's ok if it does
1.974 + // in the product build since the delta will be 0
1.975 + // and nothing will change.
1.976 + assert(false, "Unexpected value for gc costs");
1.977 + }
1.978 +
1.979 + // Use a heuristic for some number of collections to give
1.980 + // the averages time to settle down.
1.981 + switch (AdaptiveSizeThroughPutPolicy) {
1.982 + case 1:
1.983 + if (minor_collection_estimator()->increment_will_decrease() ||
1.984 + (_young_gen_change_for_minor_throughput
1.985 + <= AdaptiveSizePolicyInitializingSteps)) {
1.986 + // Expand young generation size to reduce frequency of
1.987 + // of collections.
1.988 + if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
1.989 + *desired_eden_size_ptr) {
1.990 + *desired_eden_size_ptr =
1.991 + *desired_eden_size_ptr + scaled_eden_heap_delta;
1.992 + }
1.993 + set_change_young_gen_for_throughput(
1.994 + increase_young_gen_for_througput_true);
1.995 + _young_gen_change_for_minor_throughput++;
1.996 + } else {
1.997 + // EXPERIMENTAL ADJUSTMENT
1.998 + // Record that decreasing the young gen size would decrease
1.999 + // the minor collection cost but don't do it.
1.1000 + // *desired_eden_size_ptr = _eden_size -
1.1001 + // eden_decrement_aligned_down(*desired_eden_size_ptr);
1.1002 + set_change_young_gen_for_throughput(
1.1003 + decrease_young_gen_for_througput_true);
1.1004 + }
1.1005 + break;
1.1006 + default:
1.1007 + if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
1.1008 + *desired_eden_size_ptr) {
1.1009 + *desired_eden_size_ptr =
1.1010 + *desired_eden_size_ptr + scaled_eden_heap_delta;
1.1011 + }
1.1012 + set_change_young_gen_for_throughput(
1.1013 + increase_young_gen_for_througput_true);
1.1014 + _young_gen_change_for_minor_throughput++;
1.1015 + }
1.1016 +
1.1017 + if (PrintAdaptiveSizePolicy && Verbose) {
1.1018 + gclog_or_tty->print_cr(
1.1019 + "adjusting eden for throughput (avg %f goal %f). desired_eden_size "
1.1020 + SIZE_FORMAT " eden delta " SIZE_FORMAT "\n",
1.1021 + mutator_cost(), _throughput_goal,
1.1022 + *desired_eden_size_ptr, scaled_eden_heap_delta);
1.1023 + }
1.1024 +}
1.1025 +
1.1026 +size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint(
1.1027 + size_t desired_promo_size, size_t desired_sum) {
1.1028 + assert(desired_promo_size <= desired_sum, "Inconsistent parameters");
1.1029 + set_decrease_for_footprint(decrease_old_gen_for_footprint_true);
1.1030 +
1.1031 + size_t change = promo_decrement(desired_promo_size);
1.1032 + change = scale_down(change, desired_promo_size, desired_sum);
1.1033 +
1.1034 + size_t reduced_size = desired_promo_size - change;
1.1035 +
1.1036 + if (PrintAdaptiveSizePolicy && Verbose) {
1.1037 + gclog_or_tty->print_cr(
1.1038 + "AdaptiveSizePolicy::adjust_promo_for_footprint "
1.1039 + "adjusting tenured gen for footprint. "
1.1040 + "starting promo size " SIZE_FORMAT
1.1041 + " reduced promo size " SIZE_FORMAT
1.1042 + " promo delta " SIZE_FORMAT,
1.1043 + desired_promo_size, reduced_size, change );
1.1044 + }
1.1045 +
1.1046 + assert(reduced_size <= desired_promo_size, "Inconsistent result");
1.1047 + return reduced_size;
1.1048 +}
1.1049 +
1.1050 +size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint(
1.1051 + size_t desired_eden_size, size_t desired_sum) {
1.1052 + assert(desired_eden_size <= desired_sum, "Inconsistent parameters");
1.1053 + set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
1.1054 +
1.1055 + size_t change = eden_decrement(desired_eden_size);
1.1056 + change = scale_down(change, desired_eden_size, desired_sum);
1.1057 +
1.1058 + size_t reduced_size = desired_eden_size - change;
1.1059 +
1.1060 + if (PrintAdaptiveSizePolicy && Verbose) {
1.1061 + gclog_or_tty->print_cr(
1.1062 + "AdaptiveSizePolicy::adjust_eden_for_footprint "
1.1063 + "adjusting eden for footprint. "
1.1064 + " starting eden size " SIZE_FORMAT
1.1065 + " reduced eden size " SIZE_FORMAT
1.1066 + " eden delta " SIZE_FORMAT,
1.1067 + desired_eden_size, reduced_size, change);
1.1068 + }
1.1069 +
1.1070 + assert(reduced_size <= desired_eden_size, "Inconsistent result");
1.1071 + return reduced_size;
1.1072 +}
1.1073 +
1.1074 +// Scale down "change" by the factor
1.1075 +// part / total
1.1076 +// Don't align the results.
1.1077 +
1.1078 +size_t PSAdaptiveSizePolicy::scale_down(size_t change,
1.1079 + double part,
1.1080 + double total) {
1.1081 + assert(part <= total, "Inconsistent input");
1.1082 + size_t reduced_change = change;
1.1083 + if (total > 0) {
1.1084 + double fraction = part / total;
1.1085 + reduced_change = (size_t) (fraction * (double) change);
1.1086 + }
1.1087 + assert(reduced_change <= change, "Inconsistent result");
1.1088 + return reduced_change;
1.1089 +}
1.1090 +
1.1091 +size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden,
1.1092 + uint percent_change) {
1.1093 + size_t eden_heap_delta;
1.1094 + eden_heap_delta = cur_eden / 100 * percent_change;
1.1095 + return eden_heap_delta;
1.1096 +}
1.1097 +
1.1098 +size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) {
1.1099 + return eden_increment(cur_eden, YoungGenerationSizeIncrement);
1.1100 +}
1.1101 +
1.1102 +size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
1.1103 + size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement);
1.1104 + return align_size_up(result, _space_alignment);
1.1105 +}
1.1106 +
1.1107 +size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) {
1.1108 + size_t result = eden_increment(cur_eden);
1.1109 + return align_size_down(result, _space_alignment);
1.1110 +}
1.1111 +
1.1112 +size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up(
1.1113 + size_t cur_eden) {
1.1114 + size_t result = eden_increment(cur_eden,
1.1115 + YoungGenerationSizeIncrement + _young_gen_size_increment_supplement);
1.1116 + return align_size_up(result, _space_alignment);
1.1117 +}
1.1118 +
1.1119 +size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
1.1120 + size_t eden_heap_delta = eden_decrement(cur_eden);
1.1121 + return align_size_down(eden_heap_delta, _space_alignment);
1.1122 +}
1.1123 +
1.1124 +size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
1.1125 + size_t eden_heap_delta = eden_increment(cur_eden) /
1.1126 + AdaptiveSizeDecrementScaleFactor;
1.1127 + return eden_heap_delta;
1.1128 +}
1.1129 +
1.1130 +size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo,
1.1131 + uint percent_change) {
1.1132 + size_t promo_heap_delta;
1.1133 + promo_heap_delta = cur_promo / 100 * percent_change;
1.1134 + return promo_heap_delta;
1.1135 +}
1.1136 +
1.1137 +size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) {
1.1138 + return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
1.1139 +}
1.1140 +
1.1141 +size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
1.1142 + size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
1.1143 + return align_size_up(result, _space_alignment);
1.1144 +}
1.1145 +
1.1146 +size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) {
1.1147 + size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
1.1148 + return align_size_down(result, _space_alignment);
1.1149 +}
1.1150 +
1.1151 +size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up(
1.1152 + size_t cur_promo) {
1.1153 + size_t result = promo_increment(cur_promo,
1.1154 + TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement);
1.1155 + return align_size_up(result, _space_alignment);
1.1156 +}
1.1157 +
1.1158 +size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
1.1159 + size_t promo_heap_delta = promo_decrement(cur_promo);
1.1160 + return align_size_down(promo_heap_delta, _space_alignment);
1.1161 +}
1.1162 +
1.1163 +size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
1.1164 + size_t promo_heap_delta = promo_increment(cur_promo);
1.1165 + promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
1.1166 + return promo_heap_delta;
1.1167 +}
1.1168 +
1.1169 +uint PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
1.1170 + bool is_survivor_overflow,
1.1171 + uint tenuring_threshold,
1.1172 + size_t survivor_limit) {
1.1173 + assert(survivor_limit >= _space_alignment,
1.1174 + "survivor_limit too small");
1.1175 + assert((size_t)align_size_down(survivor_limit, _space_alignment)
1.1176 + == survivor_limit, "survivor_limit not aligned");
1.1177 +
1.1178 + // This method is called even if the tenuring threshold and survivor
1.1179 + // spaces are not adjusted so that the averages are sampled above.
1.1180 + if (!UsePSAdaptiveSurvivorSizePolicy ||
1.1181 + !young_gen_policy_is_ready()) {
1.1182 + return tenuring_threshold;
1.1183 + }
1.1184 +
1.1185 + // We'll decide whether to increase or decrease the tenuring
1.1186 + // threshold based partly on the newly computed survivor size
1.1187 + // (if we hit the maximum limit allowed, we'll always choose to
1.1188 + // decrement the threshold).
1.1189 + bool incr_tenuring_threshold = false;
1.1190 + bool decr_tenuring_threshold = false;
1.1191 +
1.1192 + set_decrement_tenuring_threshold_for_gc_cost(false);
1.1193 + set_increment_tenuring_threshold_for_gc_cost(false);
1.1194 + set_decrement_tenuring_threshold_for_survivor_limit(false);
1.1195 +
1.1196 + if (!is_survivor_overflow) {
1.1197 + // Keep running averages on how much survived
1.1198 +
1.1199 + // We use the tenuring threshold to equalize the cost of major
1.1200 + // and minor collections.
1.1201 + // ThresholdTolerance is used to indicate how sensitive the
1.1202 + // tenuring threshold is to differences in cost betweent the
1.1203 + // collection types.
1.1204 +
1.1205 + // Get the times of interest. This involves a little work, so
1.1206 + // we cache the values here.
1.1207 + const double major_cost = major_gc_cost();
1.1208 + const double minor_cost = minor_gc_cost();
1.1209 +
1.1210 + if (minor_cost > major_cost * _threshold_tolerance_percent) {
1.1211 + // Minor times are getting too long; lower the threshold so
1.1212 + // less survives and more is promoted.
1.1213 + decr_tenuring_threshold = true;
1.1214 + set_decrement_tenuring_threshold_for_gc_cost(true);
1.1215 + } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
1.1216 + // Major times are too long, so we want less promotion.
1.1217 + incr_tenuring_threshold = true;
1.1218 + set_increment_tenuring_threshold_for_gc_cost(true);
1.1219 + }
1.1220 +
1.1221 + } else {
1.1222 + // Survivor space overflow occurred, so promoted and survived are
1.1223 + // not accurate. We'll make our best guess by combining survived
1.1224 + // and promoted and count them as survivors.
1.1225 + //
1.1226 + // We'll lower the tenuring threshold to see if we can correct
1.1227 + // things. Also, set the survivor size conservatively. We're
1.1228 + // trying to avoid many overflows from occurring if defnew size
1.1229 + // is just too small.
1.1230 +
1.1231 + decr_tenuring_threshold = true;
1.1232 + }
1.1233 +
1.1234 + // The padded average also maintains a deviation from the average;
1.1235 + // we use this to see how good of an estimate we have of what survived.
1.1236 + // We're trying to pad the survivor size as little as possible without
1.1237 + // overflowing the survivor spaces.
1.1238 + size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
1.1239 + _space_alignment);
1.1240 + target_size = MAX2(target_size, _space_alignment);
1.1241 +
1.1242 + if (target_size > survivor_limit) {
1.1243 + // Target size is bigger than we can handle. Let's also reduce
1.1244 + // the tenuring threshold.
1.1245 + target_size = survivor_limit;
1.1246 + decr_tenuring_threshold = true;
1.1247 + set_decrement_tenuring_threshold_for_survivor_limit(true);
1.1248 + }
1.1249 +
1.1250 + // Finally, increment or decrement the tenuring threshold, as decided above.
1.1251 + // We test for decrementing first, as we might have hit the target size
1.1252 + // limit.
1.1253 + if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1.1254 + if (tenuring_threshold > 1) {
1.1255 + tenuring_threshold--;
1.1256 + }
1.1257 + } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1.1258 + if (tenuring_threshold < MaxTenuringThreshold) {
1.1259 + tenuring_threshold++;
1.1260 + }
1.1261 + }
1.1262 +
1.1263 + // We keep a running average of the amount promoted which is used
1.1264 + // to decide when we should collect the old generation (when
1.1265 + // the amount of old gen free space is less than what we expect to
1.1266 + // promote).
1.1267 +
1.1268 + if (PrintAdaptiveSizePolicy) {
1.1269 + // A little more detail if Verbose is on
1.1270 + if (Verbose) {
1.1271 + gclog_or_tty->print( " avg_survived: %f"
1.1272 + " avg_deviation: %f",
1.1273 + _avg_survived->average(),
1.1274 + _avg_survived->deviation());
1.1275 + }
1.1276 +
1.1277 + gclog_or_tty->print( " avg_survived_padded_avg: %f",
1.1278 + _avg_survived->padded_average());
1.1279 +
1.1280 + if (Verbose) {
1.1281 + gclog_or_tty->print( " avg_promoted_avg: %f"
1.1282 + " avg_promoted_dev: %f",
1.1283 + avg_promoted()->average(),
1.1284 + avg_promoted()->deviation());
1.1285 + }
1.1286 +
1.1287 + gclog_or_tty->print_cr( " avg_promoted_padded_avg: %f"
1.1288 + " avg_pretenured_padded_avg: %f"
1.1289 + " tenuring_thresh: %d"
1.1290 + " target_size: " SIZE_FORMAT,
1.1291 + avg_promoted()->padded_average(),
1.1292 + _avg_pretenured->padded_average(),
1.1293 + tenuring_threshold, target_size);
1.1294 + }
1.1295 +
1.1296 + set_survivor_size(target_size);
1.1297 +
1.1298 + return tenuring_threshold;
1.1299 +}
1.1300 +
1.1301 +void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow,
1.1302 + size_t survived,
1.1303 + size_t promoted) {
1.1304 + // Update averages
1.1305 + if (!is_survivor_overflow) {
1.1306 + // Keep running averages on how much survived
1.1307 + _avg_survived->sample(survived);
1.1308 + } else {
1.1309 + size_t survived_guess = survived + promoted;
1.1310 + _avg_survived->sample(survived_guess);
1.1311 + }
1.1312 + avg_promoted()->sample(promoted + _avg_pretenured->padded_average());
1.1313 +
1.1314 + if (PrintAdaptiveSizePolicy) {
1.1315 + gclog_or_tty->print_cr(
1.1316 + "AdaptiveSizePolicy::update_averages:"
1.1317 + " survived: " SIZE_FORMAT
1.1318 + " promoted: " SIZE_FORMAT
1.1319 + " overflow: %s",
1.1320 + survived, promoted, is_survivor_overflow ? "true" : "false");
1.1321 + }
1.1322 +}
1.1323 +
1.1324 +bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st)
1.1325 + const {
1.1326 +
1.1327 + if (!UseAdaptiveSizePolicy) return false;
1.1328 +
1.1329 + return AdaptiveSizePolicy::print_adaptive_size_policy_on(
1.1330 + st,
1.1331 + PSScavenge::tenuring_threshold());
1.1332 +}
1.1333 +
1.1334 +#ifndef PRODUCT
1.1335 +
1.1336 +void TestOldFreeSpaceCalculation_test() {
1.1337 + assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 20) == 25, "Calculation of free memory failed");
1.1338 + assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 50) == 100, "Calculation of free memory failed");
1.1339 + assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 60) == 150, "Calculation of free memory failed");
1.1340 + assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 75) == 300, "Calculation of free memory failed");
1.1341 + assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 20) == 100, "Calculation of free memory failed");
1.1342 + assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 50) == 400, "Calculation of free memory failed");
1.1343 + assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 60) == 600, "Calculation of free memory failed");
1.1344 + assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 75) == 1200, "Calculation of free memory failed");
1.1345 +}
1.1346 +
1.1347 +#endif /* !PRODUCT */
