| /* |
| * Copyright (c) 2002, 2014, 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 "precompiled.hpp" |
| #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp" |
| #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp" |
| #include "gc_implementation/parallelScavenge/psGCAdaptivePolicyCounters.hpp" |
| #include "gc_implementation/parallelScavenge/psScavenge.hpp" |
| #include "gc_implementation/shared/gcPolicyCounters.hpp" |
| #include "gc_interface/gcCause.hpp" |
| #include "memory/collectorPolicy.hpp" |
| #include "runtime/timer.hpp" |
| #include "utilities/top.hpp" |
| |
| #include <math.h> |
| |
| PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
| |
| 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, |
| double gc_minor_pause_goal_sec, |
| uint gc_cost_ratio) : |
| AdaptiveSizePolicy(init_eden_size, |
| init_promo_size, |
| init_survivor_size, |
| gc_pause_goal_sec, |
| gc_cost_ratio), |
| _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin / 100.0), |
| _space_alignment(space_alignment), |
| _live_at_last_full_gc(init_promo_size), |
| _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec), |
| _latest_major_mutator_interval_seconds(0), |
| _young_gen_change_for_major_pause_count(0) |
| { |
| // Sizing policy statistics |
| _avg_major_pause = |
| new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding); |
| _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight); |
| _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight); |
| |
| _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); |
| _major_pause_old_estimator = |
| new LinearLeastSquareFit(AdaptiveSizePolicyWeight); |
| _major_pause_young_estimator = |
| new LinearLeastSquareFit(AdaptiveSizePolicyWeight); |
| _major_collection_estimator = |
| new LinearLeastSquareFit(AdaptiveSizePolicyWeight); |
| |
| _young_gen_size_increment_supplement = YoungGenerationSizeSupplement; |
| _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement; |
| |
| // Start the timers |
| _major_timer.start(); |
| |
| _old_gen_policy_is_ready = false; |
| } |
| |
| 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 (gc_cause != GCCause::_java_lang_system_gc || |
| UseAdaptiveSizePolicyWithSystemGC) { |
| 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); |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: " |
| "major gc cost: %f average: %f", collection_cost, |
| avg_major_gc_cost()->average()); |
| gclog_or_tty->print_cr(" 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; |
| |
| // The policy does not have enough data until at least some major collections |
| // have been done. |
| if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) { |
| _old_gen_policy_is_ready = true; |
| } |
| |
| // 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(); |
| } |
| |
| // If the remaining free space in the old generation is less that |
| // that expected to be needed by the next collection, do a full |
| // collection now. |
| bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) { |
| |
| // A similar test is done in the scavenge's should_attempt_scavenge(). If |
| // this is changed, decide if that test should also be changed. |
| bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes; |
| if (PrintGCDetails && Verbose) { |
| if (result) { |
| gclog_or_tty->print(" full after scavenge: "); |
| } else { |
| gclog_or_tty->print(" no full after scavenge: "); |
| } |
| gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT |
| " padded_average_promoted " SIZE_FORMAT |
| " free in old gen " SIZE_FORMAT, |
| (size_t) average_promoted_in_bytes(), |
| (size_t) padded_average_promoted_in_bytes(), |
| old_free_in_bytes); |
| } |
| return result; |
| } |
| |
| 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 |
| // Time statistics are updated as we go, update footprint stats here |
| _avg_base_footprint->sample(BaseFootPrintEstimate); |
| 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(is_full_gc, &desired_promo_size, &desired_eden_size); |
| |
| } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) { |
| // Adjust only for the minor pause time goal |
| adjust_eden_for_minor_pause_time(is_full_gc, &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 (PrintAdaptiveSizePolicy) { |
| if (desired_eden_size > eden_limit) { |
| gclog_or_tty->print_cr( |
| "PSAdaptiveSizePolicy::compute_eden_space_size limits:" |
| " desired_eden_size: " SIZE_FORMAT |
| " old_eden_size: " SIZE_FORMAT |
| " eden_limit: " SIZE_FORMAT |
| " cur_eden: " SIZE_FORMAT |
| " max_eden_size: " SIZE_FORMAT |
| " avg_young_live: " SIZE_FORMAT, |
| desired_eden_size, _eden_size, eden_limit, cur_eden, |
| max_eden_size, (size_t)avg_young_live()->average()); |
| } |
| if (gc_cost() > gc_cost_limit) { |
| gclog_or_tty->print_cr( |
| "PSAdaptiveSizePolicy::compute_eden_space_size: gc time limit" |
| " gc_cost: %f " |
| " GCTimeLimit: %d", |
| gc_cost(), GCTimeLimit); |
| } |
| } |
| |
| // Align everything and make a final limit check |
| desired_eden_size = align_size_up(desired_eden_size, _space_alignment); |
| desired_eden_size = MAX2(desired_eden_size, _space_alignment); |
| |
| eden_limit = align_size_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); |
| } |
| |
| if (PrintAdaptiveSizePolicy) { |
| // Timing stats |
| gclog_or_tty->print( |
| "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); |
| |
| // We give more details if Verbose is set |
| if (Verbose) { |
| gclog_or_tty->print( " 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 |
| gclog_or_tty->print( " live_space: " SIZE_FORMAT |
| " free_space: " SIZE_FORMAT, |
| live_space(), free_space()); |
| // More detail |
| if (Verbose) { |
| gclog_or_tty->print( " base_footprint: " SIZE_FORMAT |
| " avg_young_live: " SIZE_FORMAT |
| " avg_old_live: " SIZE_FORMAT, |
| (size_t)_avg_base_footprint->average(), |
| (size_t)avg_young_live()->average(), |
| (size_t)avg_old_live()->average()); |
| } |
| |
| // And finally, our old and new sizes. |
| gclog_or_tty->print(" old_eden_size: " SIZE_FORMAT |
| " desired_eden_size: " SIZE_FORMAT, |
| _eden_size, desired_eden_size); |
| gclog_or_tty->cr(); |
| } |
| |
| 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 threshhold 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(is_full_gc, &desired_promo_size, &desired_eden_size); |
| } |
| } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) { |
| // Adjust only for the minor pause time goal |
| adjust_promo_for_minor_pause_time(is_full_gc, &desired_promo_size, &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. |
| 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 (PrintAdaptiveSizePolicy) { |
| 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()); |
| gclog_or_tty->print_cr( |
| "PSAdaptiveSizePolicy::compute_old_gen_free_space limits:" |
| " desired_promo_size: " SIZE_FORMAT |
| " promo_limit: " SIZE_FORMAT |
| " free_in_old_gen: " SIZE_FORMAT |
| " max_old_gen_size: " SIZE_FORMAT |
| " avg_old_live: " SIZE_FORMAT, |
| 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) { |
| gclog_or_tty->print_cr( |
| "PSAdaptiveSizePolicy::compute_old_gen_free_space: gc time limit" |
| " gc_cost: %f " |
| " GCTimeLimit: %d", |
| gc_cost(), GCTimeLimit); |
| } |
| } |
| |
| // Align everything and make a final limit check |
| desired_promo_size = align_size_up(desired_promo_size, _space_alignment); |
| desired_promo_size = MAX2(desired_promo_size, _space_alignment); |
| |
| promo_limit = align_size_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); |
| |
| if (PrintAdaptiveSizePolicy) { |
| // Timing stats |
| gclog_or_tty->print( |
| "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); |
| |
| // We give more details if Verbose is set |
| if (Verbose) { |
| gclog_or_tty->print( " 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 |
| gclog_or_tty->print( " live_space: " SIZE_FORMAT |
| " free_space: " SIZE_FORMAT, |
| live_space(), free_space()); |
| // More detail |
| if (Verbose) { |
| gclog_or_tty->print( " base_footprint: " SIZE_FORMAT |
| " avg_young_live: " SIZE_FORMAT |
| " avg_old_live: " SIZE_FORMAT, |
| (size_t)_avg_base_footprint->average(), |
| (size_t)avg_young_live()->average(), |
| (size_t)avg_old_live()->average()); |
| } |
| |
| // And finally, our old and new sizes. |
| gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT |
| " desired_promo_size: " SIZE_FORMAT, |
| _promo_size, desired_promo_size); |
| gclog_or_tty->cr(); |
| } |
| |
| 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_promo_for_minor_pause_time(bool is_full_gc, |
| size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) { |
| |
| if (PSAdjustTenuredGenForMinorPause) { |
| if (is_full_gc) { |
| set_decide_at_full_gc(decide_at_full_gc_true); |
| } |
| // If the desired eden size is as small as it will get, |
| // try to adjust the old gen size. |
| if (*desired_eden_size_ptr <= _space_alignment) { |
| // Vary the old gen size to reduce the young gen pause. This |
| // may not be a good idea. This is just a test. |
| if (minor_pause_old_estimator()->decrement_will_decrease()) { |
| set_change_old_gen_for_min_pauses(decrease_old_gen_for_min_pauses_true); |
| *desired_promo_size_ptr = |
| _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr); |
| } else { |
| set_change_old_gen_for_min_pauses(increase_old_gen_for_min_pauses_true); |
| size_t promo_heap_delta = |
| promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr); |
| if ((*desired_promo_size_ptr + promo_heap_delta) > |
| *desired_promo_size_ptr) { |
| *desired_promo_size_ptr = |
| _promo_size + promo_heap_delta; |
| } |
| } |
| } |
| } |
| } |
| |
| void PSAdaptiveSizePolicy::adjust_eden_for_minor_pause_time(bool is_full_gc, |
| 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); |
| } else { |
| // EXPERIMENTAL ADJUSTMENT |
| // Only record that the estimator indicated such an action. |
| // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta; |
| set_change_young_gen_for_min_pauses( |
| increase_young_gen_for_min_pauses_true); |
| } |
| } |
| |
| void PSAdaptiveSizePolicy::adjust_promo_for_pause_time(bool is_full_gc, |
| size_t* desired_promo_size_ptr, |
| size_t* desired_eden_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_promo_for_minor_pause_time(is_full_gc, desired_promo_size_ptr, desired_eden_size_ptr); |
| // major pause adjustments |
| } else if (is_full_gc) { |
| // 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; |
| } else { |
| // EXPERIMENTAL ADJUSTMENT |
| // Only record that the estimator indicated such an action. |
| // *desired_promo_size_ptr = _promo_size + |
| // promo_increment_aligned_up(*desired_promo_size_ptr); |
| set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true); |
| } |
| } |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print_cr( |
| "PSAdaptiveSizePolicy::adjust_promo_for_pause_time " |
| "adjusting gen sizes for major pause (avg %f goal %f). " |
| "desired_promo_size " SIZE_FORMAT " promo delta " SIZE_FORMAT, |
| _avg_major_pause->average(), gc_pause_goal_sec(), |
| *desired_promo_size_ptr, promo_heap_delta); |
| } |
| } |
| |
| void PSAdaptiveSizePolicy::adjust_eden_for_pause_time(bool is_full_gc, |
| size_t* desired_promo_size_ptr, |
| 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(is_full_gc, |
| desired_eden_size_ptr); |
| // major pause adjustments |
| } else if (is_full_gc) { |
| // 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. |
| if (PSAdjustYoungGenForMajorPause) { |
| // If the promo size is at the minimum (i.e., the old gen |
| // size will not actually decrease), consider changing the |
| // young gen size. |
| if (*desired_promo_size_ptr < _space_alignment) { |
| // If increasing the young generation will decrease the old gen |
| // pause, do it. |
| // During startup there is noise in the statistics for deciding |
| // on whether to increase or decrease the young gen size. For |
| // some number of iterations, just try to increase the young |
| // gen size if the major pause is too long to try and establish |
| // good statistics for later decisions. |
| if (major_pause_young_estimator()->increment_will_decrease() || |
| (_young_gen_change_for_major_pause_count |
| <= AdaptiveSizePolicyInitializingSteps)) { |
| set_change_young_gen_for_maj_pauses( |
| increase_young_gen_for_maj_pauses_true); |
| eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr); |
| *desired_eden_size_ptr = _eden_size + eden_heap_delta; |
| _young_gen_change_for_major_pause_count++; |
| } else { |
| // Record that decreasing the young gen size would decrease |
| // the major pause |
| set_change_young_gen_for_maj_pauses( |
| decrease_young_gen_for_maj_pauses_true); |
| eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr); |
| *desired_eden_size_ptr = _eden_size - eden_heap_delta; |
| } |
| } |
| } |
| } |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print_cr( |
| "PSAdaptiveSizePolicy::adjust_eden_for_pause_time " |
| "adjusting gen sizes for major pause (avg %f goal %f). " |
| "desired_eden_size " SIZE_FORMAT " eden delta " SIZE_FORMAT, |
| _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; |
| } |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_promo_for_throughput(" |
| "is_full: %d, promo: " SIZE_FORMAT "): ", |
| is_full_gc, *desired_promo_size_ptr); |
| gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f " |
| "minor_gc_cost %f", 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); |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print_cr( |
| "Scaled tenured increment: " SIZE_FORMAT " by %f down to " |
| SIZE_FORMAT, |
| 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++; |
| } else { |
| // EXPERIMENTAL ADJUSTMENT |
| // Record that decreasing the old gen size would decrease |
| // the major collection cost but don't do it. |
| // *desired_promo_size_ptr = _promo_size - |
| // promo_decrement_aligned_down(*desired_promo_size_ptr); |
| set_change_old_gen_for_throughput( |
| decrease_old_gen_for_throughput_true); |
| } |
| |
| 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++; |
| } |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print_cr( |
| "adjusting tenured gen for throughput (avg %f goal %f). " |
| "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT , |
| 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; |
| } |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_eden_for_throughput(" |
| "is_full: %d, cur_eden: " SIZE_FORMAT "): ", |
| is_full_gc, *desired_eden_size_ptr); |
| gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f " |
| "minor_gc_cost %f", 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); |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print_cr( |
| "Scaled eden increment: " SIZE_FORMAT " by %f down to " |
| SIZE_FORMAT, |
| 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++; |
| } else { |
| // EXPERIMENTAL ADJUSTMENT |
| // Record that decreasing the young gen size would decrease |
| // the minor collection cost but don't do it. |
| // *desired_eden_size_ptr = _eden_size - |
| // eden_decrement_aligned_down(*desired_eden_size_ptr); |
| set_change_young_gen_for_throughput( |
| decrease_young_gen_for_througput_true); |
| } |
| 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++; |
| } |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print_cr( |
| "adjusting eden for throughput (avg %f goal %f). desired_eden_size " |
| SIZE_FORMAT " eden delta " SIZE_FORMAT "\n", |
| 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; |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print_cr( |
| "AdaptiveSizePolicy::adjust_promo_for_footprint " |
| "adjusting tenured gen for footprint. " |
| "starting promo size " SIZE_FORMAT |
| " reduced promo size " SIZE_FORMAT |
| " promo delta " SIZE_FORMAT, |
| 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; |
| |
| if (PrintAdaptiveSizePolicy && Verbose) { |
| gclog_or_tty->print_cr( |
| "AdaptiveSizePolicy::adjust_eden_for_footprint " |
| "adjusting eden for footprint. " |
| " starting eden size " SIZE_FORMAT |
| " reduced eden size " SIZE_FORMAT |
| " eden delta " SIZE_FORMAT, |
| 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(size_t cur_eden, |
| uint percent_change) { |
| size_t eden_heap_delta; |
| eden_heap_delta = cur_eden / 100 * percent_change; |
| return eden_heap_delta; |
| } |
| |
| size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) { |
| return eden_increment(cur_eden, YoungGenerationSizeIncrement); |
| } |
| |
| size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) { |
| size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement); |
| return align_size_up(result, _space_alignment); |
| } |
| |
| size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) { |
| size_t result = eden_increment(cur_eden); |
| return align_size_down(result, _space_alignment); |
| } |
| |
| 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_size_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_size_down(eden_heap_delta, _space_alignment); |
| } |
| |
| size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) { |
| size_t eden_heap_delta = eden_increment(cur_eden) / |
| AdaptiveSizeDecrementScaleFactor; |
| return eden_heap_delta; |
| } |
| |
| size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo, |
| uint percent_change) { |
| size_t promo_heap_delta; |
| promo_heap_delta = cur_promo / 100 * percent_change; |
| return promo_heap_delta; |
| } |
| |
| size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) { |
| return promo_increment(cur_promo, TenuredGenerationSizeIncrement); |
| } |
| |
| size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) { |
| size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement); |
| return align_size_up(result, _space_alignment); |
| } |
| |
| size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) { |
| size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement); |
| return align_size_down(result, _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_size_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_size_down(promo_heap_delta, _space_alignment); |
| } |
| |
| size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) { |
| size_t promo_heap_delta = promo_increment(cur_promo); |
| promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor; |
| return promo_heap_delta; |
| } |
| |
| 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((size_t)align_size_down(survivor_limit, _space_alignment) |
| == survivor_limit, "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 betweent 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_size_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 (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) { |
| if (tenuring_threshold > 1) { |
| tenuring_threshold--; |
| } |
| } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) { |
| if (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). |
| |
| if (PrintAdaptiveSizePolicy) { |
| // A little more detail if Verbose is on |
| if (Verbose) { |
| gclog_or_tty->print( " avg_survived: %f" |
| " avg_deviation: %f", |
| _avg_survived->average(), |
| _avg_survived->deviation()); |
| } |
| |
| gclog_or_tty->print( " avg_survived_padded_avg: %f", |
| _avg_survived->padded_average()); |
| |
| if (Verbose) { |
| gclog_or_tty->print( " avg_promoted_avg: %f" |
| " avg_promoted_dev: %f", |
| avg_promoted()->average(), |
| avg_promoted()->deviation()); |
| } |
| |
| gclog_or_tty->print_cr( " avg_promoted_padded_avg: %f" |
| " avg_pretenured_padded_avg: %f" |
| " tenuring_thresh: %d" |
| " target_size: " SIZE_FORMAT, |
| 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 + _avg_pretenured->padded_average()); |
| |
| if (PrintAdaptiveSizePolicy) { |
| gclog_or_tty->print_cr( |
| "AdaptiveSizePolicy::update_averages:" |
| " survived: " SIZE_FORMAT |
| " promoted: " SIZE_FORMAT |
| " overflow: %s", |
| survived, promoted, is_survivor_overflow ? "true" : "false"); |
| } |
| } |
| |
| bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) |
| const { |
| |
| if (!UseAdaptiveSizePolicy) return false; |
| |
| return AdaptiveSizePolicy::print_adaptive_size_policy_on( |
| st, |
| PSScavenge::tenuring_threshold()); |
| } |
| |
| #ifndef PRODUCT |
| |
| void TestOldFreeSpaceCalculation_test() { |
| assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 20) == 25, "Calculation of free memory failed"); |
| assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 50) == 100, "Calculation of free memory failed"); |
| assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 60) == 150, "Calculation of free memory failed"); |
| assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 75) == 300, "Calculation of free memory failed"); |
| assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 20) == 100, "Calculation of free memory failed"); |
| assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 50) == 400, "Calculation of free memory failed"); |
| assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 60) == 600, "Calculation of free memory failed"); |
| assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 75) == 1200, "Calculation of free memory failed"); |
| } |
| |
| #endif /* !PRODUCT */ |
