Mercurial > hg > graal-compiler
diff src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 0bfd3fb24150 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,1175 @@ +/* + * Copyright 2002-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +#include "incls/_precompiled.incl" +#include "incls/_psAdaptiveSizePolicy.cpp.incl" + +#include <math.h> + +PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size, + size_t init_promo_size, + size_t init_survivor_size, + size_t intra_generation_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), + _intra_generation_alignment(intra_generation_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; +} + +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_generation_free_space(size_t young_live, + size_t eden_live, + size_t old_live, + size_t perm_live, + size_t cur_eden, + size_t max_old_gen_size, + size_t max_eden_size, + bool is_full_gc, + GCCause::Cause gc_cause) { + + // Update statistics + // Time statistics are updated as we go, update footprint stats here + _avg_base_footprint->sample(BaseFootPrintEstimate + perm_live); + avg_young_live()->sample(young_live); + avg_eden_live()->sample(eden_live); + 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; + +#ifdef ASSERT + size_t original_promo_size = desired_promo_size; + size_t original_eden_size = desired_eden_size; +#endif + + // 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(); + + // Used for diagnostics + clear_generation_free_space_flags(); + + // Limits on our growth + size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average()); + + // 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; + + // 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. + adjust_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_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. + adjust_for_throughput(is_full_gc, &desired_promo_size, &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); + if (is_full_gc) { + set_decide_at_full_gc(decide_at_full_gc_true); + 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_generation_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 (desired_eden_size > eden_limit) { + gclog_or_tty->print_cr( + "AdaptiveSizePolicy::compute_generation_free_space 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( + "AdaptiveSizePolicy::compute_generation_free_space: gc time limit" + " gc_cost: %f " + " GCTimeLimit: %d", + gc_cost(), GCTimeLimit); + } + } + + // Align everything and make a final limit check + const size_t alignment = _intra_generation_alignment; + desired_eden_size = align_size_up(desired_eden_size, alignment); + desired_eden_size = MAX2(desired_eden_size, alignment); + desired_promo_size = align_size_up(desired_promo_size, alignment); + desired_promo_size = MAX2(desired_promo_size, alignment); + + eden_limit = align_size_down(eden_limit, alignment); + promo_limit = align_size_down(promo_limit, alignment); + + // Is too much time being spent in GC? + // Is the heap trying to grow beyond it's limits? + + const size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average()); + if (desired_promo_size > free_in_old_gen && desired_eden_size > eden_limit) { + + // eden_limit is the upper limit on the size of eden based on + // the maximum size of the young generation and the sizes + // of the survivor space. + // The question being asked is whether the gc costs are high + // and the space being recovered by a collection is low. + // free_in_young_gen is the free space in the young generation + // after a collection and promo_live is the free space in the old + // generation after a collection. + // + // Use the minimum of the current value of the live in the + // young gen or the average of the live in the young gen. + // If the current value drops quickly, that should be taken + // into account (i.e., don't trigger if the amount of free + // space has suddenly jumped up). If the current is much + // higher than the average, use the average since it represents + // the longer term behavor. + const size_t live_in_eden = MIN2(eden_live, (size_t) avg_eden_live()->average()); + const size_t free_in_eden = eden_limit > live_in_eden ? + eden_limit - live_in_eden : 0; + const size_t total_free_limit = free_in_old_gen + free_in_eden; + const size_t total_mem = max_old_gen_size + max_eden_size; + const double mem_free_limit = total_mem * (GCHeapFreeLimit/100.0); + if (PrintAdaptiveSizePolicy && (Verbose || + (total_free_limit < (size_t) mem_free_limit))) { + gclog_or_tty->print_cr( + "PSAdaptiveSizePolicy::compute_generation_free_space limits:" + " promo_limit: " SIZE_FORMAT + " eden_limit: " SIZE_FORMAT + " total_free_limit: " SIZE_FORMAT + " max_old_gen_size: " SIZE_FORMAT + " max_eden_size: " SIZE_FORMAT + " mem_free_limit: " SIZE_FORMAT, + promo_limit, eden_limit, total_free_limit, + max_old_gen_size, max_eden_size, + (size_t) mem_free_limit); + } + + if (is_full_gc) { + if (gc_cost() > gc_cost_limit && + total_free_limit < (size_t) mem_free_limit) { + // Collections, on average, are taking too much time, and + // gc_cost() > gc_cost_limit + // we have too little space available after a full gc. + // total_free_limit < mem_free_limit + // where + // total_free_limit is the free space available in + // both generations + // total_mem is the total space available for allocation + // in both generations (survivor spaces are not included + // just as they are not included in eden_limit). + // mem_free_limit is a fraction of total_mem judged to be an + // acceptable amount that is still unused. + // The heap can ask for the value of this variable when deciding + // whether to thrown an OutOfMemory error. + // Note that the gc time limit test only works for the collections + // of the young gen + tenured gen and not for collections of the + // permanent gen. That is because the calculation of the space + // freed by the collection is the free space in the young gen + + // tenured gen. + // Ignore explicit GC's. Ignoring explicit GC's at this level + // is the equivalent of the GC did not happen as far as the + // overhead calculation is concerted (i.e., the flag is not set + // and the count is not affected). Also the average will not + // have been updated unless UseAdaptiveSizePolicyWithSystemGC is on. + if (!GCCause::is_user_requested_gc(gc_cause) && + !GCCause::is_serviceability_requested_gc(gc_cause)) { + inc_gc_time_limit_count(); + if (UseGCOverheadLimit && + (gc_time_limit_count() > AdaptiveSizePolicyGCTimeLimitThreshold)){ + // All conditions have been met for throwing an out-of-memory + _gc_time_limit_exceeded = true; + // Avoid consecutive OOM due to the gc time limit by resetting + // the counter. + reset_gc_time_limit_count(); + } + _print_gc_time_limit_would_be_exceeded = true; + } + } else { + // Did not exceed overhead limits + reset_gc_time_limit_count(); + } + } + } + + + // 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); + } + desired_promo_size = MIN2(desired_promo_size, promo_limit); + + + if (PrintAdaptiveSizePolicy) { + // Timing stats + gclog_or_tty->print( + "PSAdaptiveSizePolicy::compute_generation_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 + " old_eden_size: " SIZE_FORMAT + " desired_promo_size: " SIZE_FORMAT + " desired_eden_size: " SIZE_FORMAT, + _promo_size, _eden_size, + desired_promo_size, desired_eden_size); + gclog_or_tty->cr(); + } + + decay_supplemental_growth(is_full_gc); + + set_promo_size(desired_promo_size); + set_eden_size(desired_eden_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_for_minor_pause_time(bool is_full_gc, + size_t* desired_promo_size_ptr, 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); + } + if (PSAdjustTenuredGenForMinorPause) { + // If the desired eden size is as small as it will get, + // try to adjust the old gen size. + if (*desired_eden_size_ptr <= _intra_generation_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_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; + size_t eden_heap_delta = 0; + // Add some checks for a threshhold for a change. For example, + // a change less than the required alignment is probably not worth + // attempting. + if (is_full_gc) { + set_decide_at_full_gc(decide_at_full_gc_true); + } + + if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) { + adjust_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 (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 < _intra_generation_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( + "AdaptiveSizePolicy::compute_generation_free_space " + "adjusting gen sizes for major pause (avg %f goal %f). " + "desired_promo_size " SIZE_FORMAT "desired_eden_size " + SIZE_FORMAT + " promo delta " SIZE_FORMAT " eden delta " SIZE_FORMAT, + _avg_major_pause->average(), gc_pause_goal_sec(), + *desired_promo_size_ptr, *desired_eden_size_ptr, + promo_heap_delta, eden_heap_delta); + } +} + +void PSAdaptiveSizePolicy::adjust_for_throughput(bool is_full_gc, + size_t* desired_promo_size_ptr, + size_t* desired_eden_size_ptr) { + + // Add some checks for a threshhold for a change. For example, + // a change less than the required alignment is probably not worth + // attempting. + if (is_full_gc) { + set_decide_at_full_gc(decide_at_full_gc_true); + } + + if ((gc_cost() + mutator_cost()) == 0.0) { + return; + } + + if (PrintAdaptiveSizePolicy && Verbose) { + gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_for_throughput(" + "is_full: %d, promo: " SIZE_FORMAT ", cur_eden: " SIZE_FORMAT "): ", + is_full_gc, *desired_promo_size_ptr, *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()); + } + + // 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); + } + } + + // 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::compute_generation_free_space " + "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::compute_generation_free_space " + "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, _intra_generation_alignment); +} + +size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) { + size_t result = eden_increment(cur_eden); + return align_size_down(result, _intra_generation_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, _intra_generation_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, _intra_generation_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, _intra_generation_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, _intra_generation_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, _intra_generation_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, _intra_generation_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; +} + +int PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold( + bool is_survivor_overflow, + int tenuring_threshold, + size_t survivor_limit) { + assert(survivor_limit >= _intra_generation_alignment, + "survivor_limit too small"); + assert((size_t)align_size_down(survivor_limit, _intra_generation_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(), + _intra_generation_alignment); + target_size = MAX2(target_size, _intra_generation_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( " 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); + tty->cr(); + } + + 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( + "AdaptiveSizePolicy::compute_survivor_space_size_and_thresh:" + " 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()); +}