| /* | |
| * Copyright (c) 2002, 2025, Oracle and/or its affiliates. All rights reserved. | |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| * | |
| * This code is free software; you can redistribute it and/or modify it | |
| * under the terms of the GNU General Public License version 2 only, as | |
| * published by the Free Software Foundation. | |
| * | |
| * This code is distributed in the hope that it will be useful, but WITHOUT | |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| * version 2 for more details (a copy is included in the LICENSE file that | |
| * accompanied this code). | |
| * | |
| * You should have received a copy of the GNU General Public License version | |
| * 2 along with this work; if not, write to the Free Software Foundation, | |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| * | |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| * or visit www.oracle.com if you need additional information or have any | |
| * questions. | |
| * | |
| */ | |
| #include "gc/parallel/parallelScavengeHeap.hpp" | |
| #include "gc/parallel/psAdaptiveSizePolicy.hpp" | |
| #include "gc/parallel/psGCAdaptivePolicyCounters.hpp" | |
| #include "gc/parallel/psScavenge.hpp" | |
| #include "gc/shared/gcCause.hpp" | |
| #include "gc/shared/gcPolicyCounters.hpp" | |
| #include "gc/shared/gcUtil.hpp" | |
| #include "logging/log.hpp" | |
| #include "runtime/timer.hpp" | |
| #include "utilities/align.hpp" | |
| #include <math.h> | |
| PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size, | |
| size_t init_promo_size, | |
| size_t init_survivor_size, | |
| size_t space_alignment, | |
| double gc_pause_goal_sec, | |
| uint gc_cost_ratio) : | |
| AdaptiveSizePolicy(init_eden_size, | |
| init_promo_size, | |
| init_survivor_size, | |
| gc_pause_goal_sec, | |
| gc_cost_ratio), | |
| _avg_major_pause(new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding)), | |
| _avg_base_footprint(new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight)), | |
| _avg_promoted(new AdaptivePaddedNoZeroDevAverage(AdaptiveSizePolicyWeight, PromotedPadding)), | |
| _major_pause_old_estimator(new LinearLeastSquareFit(AdaptiveSizePolicyWeight)), | |
| _major_pause_young_estimator(new LinearLeastSquareFit(AdaptiveSizePolicyWeight)), | |
| _latest_major_mutator_interval_seconds(0), | |
| _space_alignment(space_alignment), | |
| _live_at_last_full_gc(init_promo_size), | |
| _change_old_gen_for_min_pauses(0), | |
| _change_young_gen_for_maj_pauses(0), | |
| _young_gen_size_increment_supplement(YoungGenerationSizeSupplement), | |
| _old_gen_size_increment_supplement(TenuredGenerationSizeSupplement) | |
| { | |
| // Start the timers | |
| _major_timer.start(); | |
| } | |
| size_t PSAdaptiveSizePolicy::calculate_free_based_on_live(size_t live, uintx ratio_as_percentage) { | |
| // We want to calculate how much free memory there can be based on the | |
| // amount of live data currently in the old gen. Using the formula: | |
| // ratio * (free + live) = free | |
| // Some equation solving later we get: | |
| // free = (live * ratio) / (1 - ratio) | |
| const double ratio = ratio_as_percentage / 100.0; | |
| const double ratio_inverse = 1.0 - ratio; | |
| const double tmp = live * ratio; | |
| size_t free = (size_t)(tmp / ratio_inverse); | |
| return free; | |
| } | |
| size_t PSAdaptiveSizePolicy::calculated_old_free_size_in_bytes() const { | |
| size_t free_size = (size_t)(_promo_size + avg_promoted()->padded_average()); | |
| size_t live = ParallelScavengeHeap::heap()->old_gen()->used_in_bytes(); | |
| if (MinHeapFreeRatio != 0) { | |
| size_t min_free = calculate_free_based_on_live(live, MinHeapFreeRatio); | |
| free_size = MAX2(free_size, min_free); | |
| } | |
| if (MaxHeapFreeRatio != 100) { | |
| size_t max_free = calculate_free_based_on_live(live, MaxHeapFreeRatio); | |
| free_size = MIN2(max_free, free_size); | |
| } | |
| return free_size; | |
| } | |
| void PSAdaptiveSizePolicy::major_collection_begin() { | |
| // Update the interval time | |
| _major_timer.stop(); | |
| // Save most recent collection time | |
| _latest_major_mutator_interval_seconds = _major_timer.seconds(); | |
| _major_timer.reset(); | |
| _major_timer.start(); | |
| } | |
| void PSAdaptiveSizePolicy::update_minor_pause_old_estimator( | |
| double minor_pause_in_ms) { | |
| double promo_size_in_mbytes = ((double)_promo_size)/((double)M); | |
| _minor_pause_old_estimator->update(promo_size_in_mbytes, | |
| minor_pause_in_ms); | |
| } | |
| void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live, | |
| GCCause::Cause gc_cause) { | |
| // Update the pause time. | |
| _major_timer.stop(); | |
| if (should_update_promo_stats(gc_cause)) { | |
| double major_pause_in_seconds = _major_timer.seconds(); | |
| double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS; | |
| // Sample for performance counter | |
| _avg_major_pause->sample(major_pause_in_seconds); | |
| // Cost of collection (unit-less) | |
| double collection_cost = 0.0; | |
| if ((_latest_major_mutator_interval_seconds > 0.0) && | |
| (major_pause_in_seconds > 0.0)) { | |
| double interval_in_seconds = | |
| _latest_major_mutator_interval_seconds + major_pause_in_seconds; | |
| collection_cost = | |
| major_pause_in_seconds / interval_in_seconds; | |
| avg_major_gc_cost()->sample(collection_cost); | |
| // Sample for performance counter | |
| _avg_major_interval->sample(interval_in_seconds); | |
| } | |
| // Calculate variables used to estimate pause time vs. gen sizes | |
| double eden_size_in_mbytes = ((double)_eden_size)/((double)M); | |
| double promo_size_in_mbytes = ((double)_promo_size)/((double)M); | |
| _major_pause_old_estimator->update(promo_size_in_mbytes, | |
| major_pause_in_ms); | |
| _major_pause_young_estimator->update(eden_size_in_mbytes, | |
| major_pause_in_ms); | |
| log_trace(gc, ergo)("psAdaptiveSizePolicy::major_collection_end: major gc cost: %f average: %f", | |
| collection_cost,avg_major_gc_cost()->average()); | |
| log_trace(gc, ergo)(" major pause: %f major period %f", | |
| major_pause_in_ms, _latest_major_mutator_interval_seconds * MILLIUNITS); | |
| // Calculate variable used to estimate collection cost vs. gen sizes | |
| assert(collection_cost >= 0.0, "Expected to be non-negative"); | |
| _major_collection_estimator->update(promo_size_in_mbytes, | |
| collection_cost); | |
| } | |
| // Update the amount live at the end of a full GC | |
| _live_at_last_full_gc = amount_live; | |
| // Interval times use this timer to measure the interval that | |
| // the mutator runs. Reset after the GC pause has been measured. | |
| _major_timer.reset(); | |
| _major_timer.start(); | |
| } | |
| void PSAdaptiveSizePolicy::clear_generation_free_space_flags() { | |
| AdaptiveSizePolicy::clear_generation_free_space_flags(); | |
| set_change_old_gen_for_min_pauses(0); | |
| set_change_young_gen_for_maj_pauses(0); | |
| } | |
| // If this is not a full GC, only test and modify the young generation. | |
| void PSAdaptiveSizePolicy::compute_generations_free_space( | |
| size_t young_live, | |
| size_t eden_live, | |
| size_t old_live, | |
| size_t cur_eden, | |
| size_t max_old_gen_size, | |
| size_t max_eden_size, | |
| bool is_full_gc) { | |
| compute_eden_space_size(young_live, | |
| eden_live, | |
| cur_eden, | |
| max_eden_size, | |
| is_full_gc); | |
| compute_old_gen_free_space(old_live, | |
| cur_eden, | |
| max_old_gen_size, | |
| is_full_gc); | |
| } | |
| void PSAdaptiveSizePolicy::compute_eden_space_size( | |
| size_t young_live, | |
| size_t eden_live, | |
| size_t cur_eden, | |
| size_t max_eden_size, | |
| bool is_full_gc) { | |
| // Update statistics | |
| avg_young_live()->sample(young_live); | |
| avg_eden_live()->sample(eden_live); | |
| // This code used to return if the policy was not ready , i.e., | |
| // policy_is_ready() returning false. The intent was that | |
| // decisions below needed major collection times and so could | |
| // not be made before two major collections. A consequence was | |
| // adjustments to the young generation were not done until after | |
| // two major collections even if the minor collections times | |
| // exceeded the requested goals. Now let the young generation | |
| // adjust for the minor collection times. Major collection times | |
| // will be zero for the first collection and will naturally be | |
| // ignored. Tenured generation adjustments are only made at the | |
| // full collections so until the second major collection has | |
| // been reached, no tenured generation adjustments will be made. | |
| // Until we know better, desired promotion size uses the last calculation | |
| size_t desired_promo_size = _promo_size; | |
| // Start eden at the current value. The desired value that is stored | |
| // in _eden_size is not bounded by constraints of the heap and can | |
| // run away. | |
| // | |
| // As expected setting desired_eden_size to the current | |
| // value of desired_eden_size as a starting point | |
| // caused desired_eden_size to grow way too large and caused | |
| // an overflow down stream. It may have improved performance in | |
| // some case but is dangerous. | |
| size_t desired_eden_size = cur_eden; | |
| // Cache some values. There's a bit of work getting these, so | |
| // we might save a little time. | |
| const double major_cost = major_gc_cost(); | |
| const double minor_cost = minor_gc_cost(); | |
| // This method sets the desired eden size. That plus the | |
| // desired survivor space sizes sets the desired young generation | |
| // size. This methods does not know what the desired survivor | |
| // size is but expects that other policy will attempt to make | |
| // the survivor sizes compatible with the live data in the | |
| // young generation. This limit is an estimate of the space left | |
| // in the young generation after the survivor spaces have been | |
| // subtracted out. | |
| size_t eden_limit = max_eden_size; | |
| const double gc_cost_limit = GCTimeLimit / 100.0; | |
| // Which way should we go? | |
| // if pause requirement is not met | |
| // adjust size of any generation with average paus exceeding | |
| // the pause limit. Adjust one pause at a time (the larger) | |
| // and only make adjustments for the major pause at full collections. | |
| // else if throughput requirement not met | |
| // adjust the size of the generation with larger gc time. Only | |
| // adjust one generation at a time. | |
| // else | |
| // adjust down the total heap size. Adjust down the larger of the | |
| // generations. | |
| // Add some checks for a threshold for a change. For example, | |
| // a change less than the necessary alignment is probably not worth | |
| // attempting. | |
| if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) || | |
| (_avg_major_pause->padded_average() > gc_pause_goal_sec())) { | |
| // | |
| // Check pauses | |
| // | |
| // Make changes only to affect one of the pauses (the larger) | |
| // at a time. | |
| adjust_eden_for_pause_time(&desired_eden_size); | |
| } else if (_avg_minor_pause->padded_average() > gc_pause_goal_sec()) { | |
| // Adjust only for the minor pause time goal | |
| adjust_eden_for_minor_pause_time(&desired_eden_size); | |
| } else if(adjusted_mutator_cost() < _throughput_goal) { | |
| // This branch used to require that (mutator_cost() > 0.0 in 1.4.2. | |
| // This sometimes resulted in skipping to the minimize footprint | |
| // code. Change this to try and reduce GC time if mutator time is | |
| // negative for whatever reason. Or for future consideration, | |
| // bail out of the code if mutator time is negative. | |
| // | |
| // Throughput | |
| // | |
| assert(major_cost >= 0.0, "major cost is < 0.0"); | |
| assert(minor_cost >= 0.0, "minor cost is < 0.0"); | |
| // Try to reduce the GC times. | |
| adjust_eden_for_throughput(is_full_gc, &desired_eden_size); | |
| } else { | |
| // Be conservative about reducing the footprint. | |
| // Do a minimum number of major collections first. | |
| // Have reasonable averages for major and minor collections costs. | |
| if (UseAdaptiveSizePolicyFootprintGoal && | |
| young_gen_policy_is_ready() && | |
| avg_major_gc_cost()->average() >= 0.0 && | |
| avg_minor_gc_cost()->average() >= 0.0) { | |
| size_t desired_sum = desired_eden_size + desired_promo_size; | |
| desired_eden_size = adjust_eden_for_footprint(desired_eden_size, desired_sum); | |
| } | |
| } | |
| // Note we make the same tests as in the code block below; the code | |
| // seems a little easier to read with the printing in another block. | |
| if (desired_eden_size > eden_limit) { | |
| log_debug(gc, ergo)( | |
| "PSAdaptiveSizePolicy::compute_eden_space_size limits:" | |
| " desired_eden_size: %zu" | |
| " old_eden_size: %zu" | |
| " eden_limit: %zu" | |
| " cur_eden: %zu" | |
| " max_eden_size: %zu" | |
| " avg_young_live: %zu", | |
| desired_eden_size, _eden_size, eden_limit, cur_eden, | |
| max_eden_size, (size_t)avg_young_live()->average()); | |
| } | |
| if (gc_cost() > gc_cost_limit) { | |
| log_debug(gc, ergo)( | |
| "PSAdaptiveSizePolicy::compute_eden_space_size: gc time limit" | |
| " gc_cost: %f " | |
| " GCTimeLimit: %u", | |
| gc_cost(), GCTimeLimit); | |
| } | |
| // Align everything and make a final limit check | |
| desired_eden_size = align_up(desired_eden_size, _space_alignment); | |
| desired_eden_size = MAX2(desired_eden_size, _space_alignment); | |
| eden_limit = align_down(eden_limit, _space_alignment); | |
| // And one last limit check, now that we've aligned things. | |
| if (desired_eden_size > eden_limit) { | |
| // If the policy says to get a larger eden but | |
| // is hitting the limit, don't decrease eden. | |
| // This can lead to a general drifting down of the | |
| // eden size. Let the tenuring calculation push more | |
| // into the old gen. | |
| desired_eden_size = MAX2(eden_limit, cur_eden); | |
| } | |
| log_debug(gc, ergo)("PSAdaptiveSizePolicy::compute_eden_space_size: costs minor_time: %f major_cost: %f mutator_cost: %f throughput_goal: %f", | |
| minor_gc_cost(), major_gc_cost(), mutator_cost(), _throughput_goal); | |
| log_trace(gc, ergo)("Minor_pause: %f major_pause: %f minor_interval: %f major_interval: %fpause_goal: %f", | |
| _avg_minor_pause->padded_average(), | |
| _avg_major_pause->padded_average(), | |
| _avg_minor_interval->average(), | |
| _avg_major_interval->average(), | |
| gc_pause_goal_sec()); | |
| log_debug(gc, ergo)("Live_space: %zu free_space: %zu", | |
| live_space(), free_space()); | |
| log_trace(gc, ergo)("avg_young_live: %zu avg_old_live: %zu", | |
| (size_t)avg_young_live()->average(), | |
| (size_t)avg_old_live()->average()); | |
| log_debug(gc, ergo)("Old eden_size: %zu desired_eden_size: %zu", | |
| _eden_size, desired_eden_size); | |
| set_eden_size(desired_eden_size); | |
| } | |
| void PSAdaptiveSizePolicy::compute_old_gen_free_space( | |
| size_t old_live, | |
| size_t cur_eden, | |
| size_t max_old_gen_size, | |
| bool is_full_gc) { | |
| // Update statistics | |
| // Time statistics are updated as we go, update footprint stats here | |
| if (is_full_gc) { | |
| // old_live is only accurate after a full gc | |
| avg_old_live()->sample(old_live); | |
| } | |
| // This code used to return if the policy was not ready , i.e., | |
| // policy_is_ready() returning false. The intent was that | |
| // decisions below needed major collection times and so could | |
| // not be made before two major collections. A consequence was | |
| // adjustments to the young generation were not done until after | |
| // two major collections even if the minor collections times | |
| // exceeded the requested goals. Now let the young generation | |
| // adjust for the minor collection times. Major collection times | |
| // will be zero for the first collection and will naturally be | |
| // ignored. Tenured generation adjustments are only made at the | |
| // full collections so until the second major collection has | |
| // been reached, no tenured generation adjustments will be made. | |
| // Until we know better, desired promotion size uses the last calculation | |
| size_t desired_promo_size = _promo_size; | |
| // Start eden at the current value. The desired value that is stored | |
| // in _eden_size is not bounded by constraints of the heap and can | |
| // run away. | |
| // | |
| // As expected setting desired_eden_size to the current | |
| // value of desired_eden_size as a starting point | |
| // caused desired_eden_size to grow way too large and caused | |
| // an overflow down stream. It may have improved performance in | |
| // some case but is dangerous. | |
| size_t desired_eden_size = cur_eden; | |
| // Cache some values. There's a bit of work getting these, so | |
| // we might save a little time. | |
| const double major_cost = major_gc_cost(); | |
| const double minor_cost = minor_gc_cost(); | |
| // Limits on our growth | |
| size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average()); | |
| // But don't force a promo size below the current promo size. Otherwise, | |
| // the promo size will shrink for no good reason. | |
| promo_limit = MAX2(promo_limit, _promo_size); | |
| const double gc_cost_limit = GCTimeLimit/100.0; | |
| // Which way should we go? | |
| // if pause requirement is not met | |
| // adjust size of any generation with average paus exceeding | |
| // the pause limit. Adjust one pause at a time (the larger) | |
| // and only make adjustments for the major pause at full collections. | |
| // else if throughput requirement not met | |
| // adjust the size of the generation with larger gc time. Only | |
| // adjust one generation at a time. | |
| // else | |
| // adjust down the total heap size. Adjust down the larger of the | |
| // generations. | |
| // Add some checks for a threshold for a change. For example, | |
| // a change less than the necessary alignment is probably not worth | |
| // attempting. | |
| if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) || | |
| (_avg_major_pause->padded_average() > gc_pause_goal_sec())) { | |
| // | |
| // Check pauses | |
| // | |
| // Make changes only to affect one of the pauses (the larger) | |
| // at a time. | |
| if (is_full_gc) { | |
| set_decide_at_full_gc(decide_at_full_gc_true); | |
| adjust_promo_for_pause_time(&desired_promo_size); | |
| } | |
| } else if (adjusted_mutator_cost() < _throughput_goal) { | |
| // This branch used to require that (mutator_cost() > 0.0 in 1.4.2. | |
| // This sometimes resulted in skipping to the minimize footprint | |
| // code. Change this to try and reduce GC time if mutator time is | |
| // negative for whatever reason. Or for future consideration, | |
| // bail out of the code if mutator time is negative. | |
| // | |
| // Throughput | |
| // | |
| assert(major_cost >= 0.0, "major cost is < 0.0"); | |
| assert(minor_cost >= 0.0, "minor cost is < 0.0"); | |
| // Try to reduce the GC times. | |
| if (is_full_gc) { | |
| set_decide_at_full_gc(decide_at_full_gc_true); | |
| adjust_promo_for_throughput(is_full_gc, &desired_promo_size); | |
| } | |
| } else { | |
| // Be conservative about reducing the footprint. | |
| // Do a minimum number of major collections first. | |
| // Have reasonable averages for major and minor collections costs. | |
| if (UseAdaptiveSizePolicyFootprintGoal && | |
| young_gen_policy_is_ready() && | |
| avg_major_gc_cost()->average() >= 0.0 && | |
| avg_minor_gc_cost()->average() >= 0.0) { | |
| if (is_full_gc) { | |
| set_decide_at_full_gc(decide_at_full_gc_true); | |
| size_t desired_sum = desired_eden_size + desired_promo_size; | |
| desired_promo_size = adjust_promo_for_footprint(desired_promo_size, desired_sum); | |
| } | |
| } | |
| } | |
| // Note we make the same tests as in the code block below; the code | |
| // seems a little easier to read with the printing in another block. | |
| if (desired_promo_size > promo_limit) { | |
| // "free_in_old_gen" was the original value for used for promo_limit | |
| size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average()); | |
| log_debug(gc, ergo)( | |
| "PSAdaptiveSizePolicy::compute_old_gen_free_space limits:" | |
| " desired_promo_size: %zu" | |
| " promo_limit: %zu" | |
| " free_in_old_gen: %zu" | |
| " max_old_gen_size: %zu" | |
| " avg_old_live: %zu", | |
| desired_promo_size, promo_limit, free_in_old_gen, | |
| max_old_gen_size, (size_t) avg_old_live()->average()); | |
| } | |
| if (gc_cost() > gc_cost_limit) { | |
| log_debug(gc, ergo)( | |
| "PSAdaptiveSizePolicy::compute_old_gen_free_space: gc time limit" | |
| " gc_cost: %f " | |
| " GCTimeLimit: %u", | |
| gc_cost(), GCTimeLimit); | |
| } | |
| // Align everything and make a final limit check | |
| desired_promo_size = align_up(desired_promo_size, _space_alignment); | |
| desired_promo_size = MAX2(desired_promo_size, _space_alignment); | |
| promo_limit = align_down(promo_limit, _space_alignment); | |
| // And one last limit check, now that we've aligned things. | |
| desired_promo_size = MIN2(desired_promo_size, promo_limit); | |
| // Timing stats | |
| log_debug(gc, ergo)("PSAdaptiveSizePolicy::compute_old_gen_free_space: costs minor_time: %f major_cost: %f mutator_cost: %f throughput_goal: %f", | |
| minor_gc_cost(), major_gc_cost(), mutator_cost(), _throughput_goal); | |
| log_trace(gc, ergo)("Minor_pause: %f major_pause: %f minor_interval: %f major_interval: %f pause_goal: %f", | |
| _avg_minor_pause->padded_average(), | |
| _avg_major_pause->padded_average(), | |
| _avg_minor_interval->average(), | |
| _avg_major_interval->average(), | |
| gc_pause_goal_sec()); | |
| // Footprint stats | |
| log_debug(gc, ergo)("Live_space: %zu free_space: %zu", | |
| live_space(), free_space()); | |
| log_trace(gc, ergo)("avg_young_live: %zu avg_old_live: %zu", | |
| (size_t)avg_young_live()->average(), | |
| (size_t)avg_old_live()->average()); | |
| log_debug(gc, ergo)("Old promo_size: %zu desired_promo_size: %zu", | |
| _promo_size, desired_promo_size); | |
| set_promo_size(desired_promo_size); | |
| } | |
| void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) { | |
| // Decay the supplemental increment? Decay the supplement growth | |
| // factor even if it is not used. It is only meant to give a boost | |
| // to the initial growth and if it is not used, then it was not | |
| // needed. | |
| if (is_full_gc) { | |
| // Don't wait for the threshold value for the major collections. If | |
| // here, the supplemental growth term was used and should decay. | |
| if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay) | |
| == 0) { | |
| _old_gen_size_increment_supplement = | |
| _old_gen_size_increment_supplement >> 1; | |
| } | |
| } else { | |
| if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) && | |
| (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) { | |
| _young_gen_size_increment_supplement = | |
| _young_gen_size_increment_supplement >> 1; | |
| } | |
| } | |
| } | |
| void PSAdaptiveSizePolicy::adjust_eden_for_minor_pause_time(size_t* desired_eden_size_ptr) { | |
| // Adjust the young generation size to reduce pause time of | |
| // of collections. | |
| // | |
| // The AdaptiveSizePolicyInitializingSteps test is not used | |
| // here. It has not seemed to be needed but perhaps should | |
| // be added for consistency. | |
| if (minor_pause_young_estimator()->decrement_will_decrease()) { | |
| // reduce eden size | |
| set_change_young_gen_for_min_pauses( | |
| decrease_young_gen_for_min_pauses_true); | |
| *desired_eden_size_ptr = *desired_eden_size_ptr - | |
| eden_decrement_aligned_down(*desired_eden_size_ptr); | |
| } | |
| } | |
| void PSAdaptiveSizePolicy::adjust_promo_for_pause_time(size_t* desired_promo_size_ptr) { | |
| size_t promo_heap_delta = 0; | |
| // Add some checks for a threshold for a change. For example, | |
| // a change less than the required alignment is probably not worth | |
| // attempting. | |
| if (_avg_minor_pause->padded_average() <= _avg_major_pause->padded_average()) { | |
| // Adjust for the major pause time only at full gc's because the | |
| // affects of a change can only be seen at full gc's. | |
| // Reduce old generation size to reduce pause? | |
| if (major_pause_old_estimator()->decrement_will_decrease()) { | |
| // reduce old generation size | |
| set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true); | |
| promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr); | |
| *desired_promo_size_ptr = _promo_size - promo_heap_delta; | |
| } | |
| } | |
| log_trace(gc, ergo)( | |
| "PSAdaptiveSizePolicy::adjust_promo_for_pause_time " | |
| "adjusting gen sizes for major pause (avg %f goal %f). " | |
| "desired_promo_size %zu promo delta %zu", | |
| _avg_major_pause->average(), gc_pause_goal_sec(), | |
| *desired_promo_size_ptr, promo_heap_delta); | |
| } | |
| void PSAdaptiveSizePolicy::adjust_eden_for_pause_time(size_t* desired_eden_size_ptr) { | |
| size_t eden_heap_delta = 0; | |
| // Add some checks for a threshold for a change. For example, | |
| // a change less than the required alignment is probably not worth | |
| // attempting. | |
| if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) { | |
| adjust_eden_for_minor_pause_time(desired_eden_size_ptr); | |
| } | |
| log_trace(gc, ergo)( | |
| "PSAdaptiveSizePolicy::adjust_eden_for_pause_time " | |
| "adjusting gen sizes for major pause (avg %f goal %f). " | |
| "desired_eden_size %zu eden delta %zu", | |
| _avg_major_pause->average(), gc_pause_goal_sec(), | |
| *desired_eden_size_ptr, eden_heap_delta); | |
| } | |
| void PSAdaptiveSizePolicy::adjust_promo_for_throughput(bool is_full_gc, | |
| size_t* desired_promo_size_ptr) { | |
| // Add some checks for a threshold for a change. For example, | |
| // a change less than the required alignment is probably not worth | |
| // attempting. | |
| if ((gc_cost() + mutator_cost()) == 0.0) { | |
| return; | |
| } | |
| log_trace(gc, ergo)("PSAdaptiveSizePolicy::adjust_promo_for_throughput(is_full: %d, promo: %zu): mutator_cost %f major_gc_cost %f minor_gc_cost %f", | |
| is_full_gc, *desired_promo_size_ptr, mutator_cost(), major_gc_cost(), minor_gc_cost()); | |
| // Tenured generation | |
| if (is_full_gc) { | |
| // Calculate the change to use for the tenured gen. | |
| size_t scaled_promo_heap_delta = 0; | |
| // Can the increment to the generation be scaled? | |
| if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) { | |
| size_t promo_heap_delta = | |
| promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr); | |
| double scale_by_ratio = major_gc_cost() / gc_cost(); | |
| scaled_promo_heap_delta = | |
| (size_t) (scale_by_ratio * (double) promo_heap_delta); | |
| log_trace(gc, ergo)("Scaled tenured increment: %zu by %f down to %zu", | |
| promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta); | |
| } else if (major_gc_cost() >= 0.0) { | |
| // Scaling is not going to work. If the major gc time is the | |
| // larger, give it a full increment. | |
| if (major_gc_cost() >= minor_gc_cost()) { | |
| scaled_promo_heap_delta = | |
| promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr); | |
| } | |
| } else { | |
| // Don't expect to get here but it's ok if it does | |
| // in the product build since the delta will be 0 | |
| // and nothing will change. | |
| assert(false, "Unexpected value for gc costs"); | |
| } | |
| switch (AdaptiveSizeThroughPutPolicy) { | |
| case 1: | |
| // Early in the run the statistics might not be good. Until | |
| // a specific number of collections have been, use the heuristic | |
| // that a larger generation size means lower collection costs. | |
| if (major_collection_estimator()->increment_will_decrease() || | |
| (_old_gen_change_for_major_throughput | |
| <= AdaptiveSizePolicyInitializingSteps)) { | |
| // Increase tenured generation size to reduce major collection cost | |
| if ((*desired_promo_size_ptr + scaled_promo_heap_delta) > | |
| *desired_promo_size_ptr) { | |
| *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta; | |
| } | |
| set_change_old_gen_for_throughput( | |
| increase_old_gen_for_throughput_true); | |
| _old_gen_change_for_major_throughput++; | |
| } | |
| break; | |
| default: | |
| // Simplest strategy | |
| if ((*desired_promo_size_ptr + scaled_promo_heap_delta) > | |
| *desired_promo_size_ptr) { | |
| *desired_promo_size_ptr = *desired_promo_size_ptr + | |
| scaled_promo_heap_delta; | |
| } | |
| set_change_old_gen_for_throughput( | |
| increase_old_gen_for_throughput_true); | |
| _old_gen_change_for_major_throughput++; | |
| } | |
| log_trace(gc, ergo)("Adjusting tenured gen for throughput (avg %f goal %f). desired_promo_size %zu promo_delta %zu", | |
| mutator_cost(), | |
| _throughput_goal, | |
| *desired_promo_size_ptr, scaled_promo_heap_delta); | |
| } | |
| } | |
| void PSAdaptiveSizePolicy::adjust_eden_for_throughput(bool is_full_gc, | |
| size_t* desired_eden_size_ptr) { | |
| // Add some checks for a threshold for a change. For example, | |
| // a change less than the required alignment is probably not worth | |
| // attempting. | |
| if ((gc_cost() + mutator_cost()) == 0.0) { | |
| return; | |
| } | |
| log_trace(gc, ergo)("PSAdaptiveSizePolicy::adjust_eden_for_throughput(is_full: %d, cur_eden: %zu): mutator_cost %f major_gc_cost %f minor_gc_cost %f", | |
| is_full_gc, *desired_eden_size_ptr, mutator_cost(), major_gc_cost(), minor_gc_cost()); | |
| // Young generation | |
| size_t scaled_eden_heap_delta = 0; | |
| // Can the increment to the generation be scaled? | |
| if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) { | |
| size_t eden_heap_delta = | |
| eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr); | |
| double scale_by_ratio = minor_gc_cost() / gc_cost(); | |
| assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong"); | |
| scaled_eden_heap_delta = | |
| (size_t) (scale_by_ratio * (double) eden_heap_delta); | |
| log_trace(gc, ergo)("Scaled eden increment: %zu by %f down to %zu", | |
| eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta); | |
| } else if (minor_gc_cost() >= 0.0) { | |
| // Scaling is not going to work. If the minor gc time is the | |
| // larger, give it a full increment. | |
| if (minor_gc_cost() > major_gc_cost()) { | |
| scaled_eden_heap_delta = | |
| eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr); | |
| } | |
| } else { | |
| // Don't expect to get here but it's ok if it does | |
| // in the product build since the delta will be 0 | |
| // and nothing will change. | |
| assert(false, "Unexpected value for gc costs"); | |
| } | |
| // Use a heuristic for some number of collections to give | |
| // the averages time to settle down. | |
| switch (AdaptiveSizeThroughPutPolicy) { | |
| case 1: | |
| if (minor_collection_estimator()->increment_will_decrease() || | |
| (_young_gen_change_for_minor_throughput | |
| <= AdaptiveSizePolicyInitializingSteps)) { | |
| // Expand young generation size to reduce frequency of | |
| // of collections. | |
| if ((*desired_eden_size_ptr + scaled_eden_heap_delta) > | |
| *desired_eden_size_ptr) { | |
| *desired_eden_size_ptr = | |
| *desired_eden_size_ptr + scaled_eden_heap_delta; | |
| } | |
| set_change_young_gen_for_throughput( | |
| increase_young_gen_for_througput_true); | |
| _young_gen_change_for_minor_throughput++; | |
| } | |
| break; | |
| default: | |
| if ((*desired_eden_size_ptr + scaled_eden_heap_delta) > | |
| *desired_eden_size_ptr) { | |
| *desired_eden_size_ptr = | |
| *desired_eden_size_ptr + scaled_eden_heap_delta; | |
| } | |
| set_change_young_gen_for_throughput( | |
| increase_young_gen_for_througput_true); | |
| _young_gen_change_for_minor_throughput++; | |
| } | |
| log_trace(gc, ergo)("Adjusting eden for throughput (avg %f goal %f). desired_eden_size %zu eden delta %zu", | |
| mutator_cost(), _throughput_goal, *desired_eden_size_ptr, scaled_eden_heap_delta); | |
| } | |
| size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint( | |
| size_t desired_promo_size, size_t desired_sum) { | |
| assert(desired_promo_size <= desired_sum, "Inconsistent parameters"); | |
| set_decrease_for_footprint(decrease_old_gen_for_footprint_true); | |
| size_t change = promo_decrement(desired_promo_size); | |
| change = scale_down(change, desired_promo_size, desired_sum); | |
| size_t reduced_size = desired_promo_size - change; | |
| log_trace(gc, ergo)( | |
| "AdaptiveSizePolicy::adjust_promo_for_footprint " | |
| "adjusting tenured gen for footprint. " | |
| "starting promo size %zu" | |
| " reduced promo size %zu" | |
| " promo delta %zu", | |
| desired_promo_size, reduced_size, change ); | |
| assert(reduced_size <= desired_promo_size, "Inconsistent result"); | |
| return reduced_size; | |
| } | |
| size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint( | |
| size_t desired_eden_size, size_t desired_sum) { | |
| assert(desired_eden_size <= desired_sum, "Inconsistent parameters"); | |
| set_decrease_for_footprint(decrease_young_gen_for_footprint_true); | |
| size_t change = eden_decrement(desired_eden_size); | |
| change = scale_down(change, desired_eden_size, desired_sum); | |
| size_t reduced_size = desired_eden_size - change; | |
| log_trace(gc, ergo)( | |
| "AdaptiveSizePolicy::adjust_eden_for_footprint " | |
| "adjusting eden for footprint. " | |
| " starting eden size %zu" | |
| " reduced eden size %zu" | |
| " eden delta %zu", | |
| desired_eden_size, reduced_size, change); | |
| assert(reduced_size <= desired_eden_size, "Inconsistent result"); | |
| return reduced_size; | |
| } | |
| // Scale down "change" by the factor | |
| // part / total | |
| // Don't align the results. | |
| size_t PSAdaptiveSizePolicy::scale_down(size_t change, | |
| double part, | |
| double total) { | |
| assert(part <= total, "Inconsistent input"); | |
| size_t reduced_change = change; | |
| if (total > 0) { | |
| double fraction = part / total; | |
| reduced_change = (size_t) (fraction * (double) change); | |
| } | |
| assert(reduced_change <= change, "Inconsistent result"); | |
| return reduced_change; | |
| } | |
| size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up( | |
| size_t cur_eden) { | |
| size_t result = eden_increment(cur_eden, | |
| YoungGenerationSizeIncrement + _young_gen_size_increment_supplement); | |
| return align_up(result, _space_alignment); | |
| } | |
| size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) { | |
| size_t eden_heap_delta = eden_decrement(cur_eden); | |
| return align_down(eden_heap_delta, _space_alignment); | |
| } | |
| size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up( | |
| size_t cur_promo) { | |
| size_t result = promo_increment(cur_promo, | |
| TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement); | |
| return align_up(result, _space_alignment); | |
| } | |
| size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) { | |
| size_t promo_heap_delta = promo_decrement(cur_promo); | |
| return align_down(promo_heap_delta, _space_alignment); | |
| } | |
| uint PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold( | |
| bool is_survivor_overflow, | |
| uint tenuring_threshold, | |
| size_t survivor_limit) { | |
| assert(survivor_limit >= _space_alignment, | |
| "survivor_limit too small"); | |
| assert(is_aligned(survivor_limit, _space_alignment), | |
| "survivor_limit not aligned"); | |
| // This method is called even if the tenuring threshold and survivor | |
| // spaces are not adjusted so that the averages are sampled above. | |
| if (!UsePSAdaptiveSurvivorSizePolicy || | |
| !young_gen_policy_is_ready()) { | |
| return tenuring_threshold; | |
| } | |
| // We'll decide whether to increase or decrease the tenuring | |
| // threshold based partly on the newly computed survivor size | |
| // (if we hit the maximum limit allowed, we'll always choose to | |
| // decrement the threshold). | |
| bool incr_tenuring_threshold = false; | |
| bool decr_tenuring_threshold = false; | |
| set_decrement_tenuring_threshold_for_gc_cost(false); | |
| set_increment_tenuring_threshold_for_gc_cost(false); | |
| set_decrement_tenuring_threshold_for_survivor_limit(false); | |
| if (!is_survivor_overflow) { | |
| // Keep running averages on how much survived | |
| // We use the tenuring threshold to equalize the cost of major | |
| // and minor collections. | |
| // ThresholdTolerance is used to indicate how sensitive the | |
| // tenuring threshold is to differences in cost between the | |
| // collection types. | |
| // Get the times of interest. This involves a little work, so | |
| // we cache the values here. | |
| const double major_cost = major_gc_cost(); | |
| const double minor_cost = minor_gc_cost(); | |
| if (minor_cost > major_cost * _threshold_tolerance_percent) { | |
| // Minor times are getting too long; lower the threshold so | |
| // less survives and more is promoted. | |
| decr_tenuring_threshold = true; | |
| set_decrement_tenuring_threshold_for_gc_cost(true); | |
| } else if (major_cost > minor_cost * _threshold_tolerance_percent) { | |
| // Major times are too long, so we want less promotion. | |
| incr_tenuring_threshold = true; | |
| set_increment_tenuring_threshold_for_gc_cost(true); | |
| } | |
| } else { | |
| // Survivor space overflow occurred, so promoted and survived are | |
| // not accurate. We'll make our best guess by combining survived | |
| // and promoted and count them as survivors. | |
| // | |
| // We'll lower the tenuring threshold to see if we can correct | |
| // things. Also, set the survivor size conservatively. We're | |
| // trying to avoid many overflows from occurring if defnew size | |
| // is just too small. | |
| decr_tenuring_threshold = true; | |
| } | |
| // The padded average also maintains a deviation from the average; | |
| // we use this to see how good of an estimate we have of what survived. | |
| // We're trying to pad the survivor size as little as possible without | |
| // overflowing the survivor spaces. | |
| size_t target_size = align_up((size_t)_avg_survived->padded_average(), | |
| _space_alignment); | |
| target_size = MAX2(target_size, _space_alignment); | |
| if (target_size > survivor_limit) { | |
| // Target size is bigger than we can handle. Let's also reduce | |
| // the tenuring threshold. | |
| target_size = survivor_limit; | |
| decr_tenuring_threshold = true; | |
| set_decrement_tenuring_threshold_for_survivor_limit(true); | |
| } | |
| // Finally, increment or decrement the tenuring threshold, as decided above. | |
| // We test for decrementing first, as we might have hit the target size | |
| // limit. | |
| if (!(AlwaysTenure || NeverTenure)) { | |
| if (decr_tenuring_threshold && tenuring_threshold > 1) { | |
| tenuring_threshold--; | |
| } else if (incr_tenuring_threshold && tenuring_threshold < MaxTenuringThreshold) { | |
| tenuring_threshold++; | |
| } | |
| } | |
| // We keep a running average of the amount promoted which is used | |
| // to decide when we should collect the old generation (when | |
| // the amount of old gen free space is less than what we expect to | |
| // promote). | |
| log_trace(gc, ergo)("avg_survived: %f avg_deviation: %f", _avg_survived->average(), _avg_survived->deviation()); | |
| log_debug(gc, ergo)("avg_survived_padded_avg: %f", _avg_survived->padded_average()); | |
| log_trace(gc, ergo)("avg_promoted_avg: %f avg_promoted_dev: %f", avg_promoted()->average(), avg_promoted()->deviation()); | |
| log_debug(gc, ergo)("avg_promoted_padded_avg: %f avg_pretenured_padded_avg: %f tenuring_thresh: %d target_size: %zu", | |
| avg_promoted()->padded_average(), | |
| _avg_pretenured->padded_average(), | |
| tenuring_threshold, target_size); | |
| set_survivor_size(target_size); | |
| return tenuring_threshold; | |
| } | |
| void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow, | |
| size_t survived, | |
| size_t promoted) { | |
| // Update averages | |
| if (!is_survivor_overflow) { | |
| // Keep running averages on how much survived | |
| _avg_survived->sample(survived); | |
| } else { | |
| size_t survived_guess = survived + promoted; | |
| _avg_survived->sample(survived_guess); | |
| } | |
| avg_promoted()->sample(promoted); | |
| log_trace(gc, ergo)("AdaptiveSizePolicy::update_averages: survived: %zu promoted: %zu overflow: %s", | |
| survived, promoted, is_survivor_overflow ? "true" : "false"); | |
| } | |
| bool PSAdaptiveSizePolicy::print() const { | |
| if (!UseAdaptiveSizePolicy) { | |
| return false; | |
| } | |
| if (AdaptiveSizePolicy::print()) { | |
| AdaptiveSizePolicy::print_tenuring_threshold(PSScavenge::tenuring_threshold()); | |
| return true; | |
| } | |
| return false; | |
| } |