Mercurial > hg > graal-jvmci-8
view src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp @ 997:46b819ba120b
Merge
author | jrose |
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date | Wed, 30 Sep 2009 13:25:39 -0700 |
parents | a61af66fc99e |
children | 0bfd3fb24150 |
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/* * Copyright 2004-2006 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/_adaptiveSizePolicy.cpp.incl" elapsedTimer AdaptiveSizePolicy::_minor_timer; elapsedTimer AdaptiveSizePolicy::_major_timer; // The throughput goal is implemented as // _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio)) // gc_cost_ratio is the ratio // application cost / gc cost // For example a gc_cost_ratio of 4 translates into a // throughput goal of .80 AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size, size_t init_promo_size, size_t init_survivor_size, double gc_pause_goal_sec, uint gc_cost_ratio) : _eden_size(init_eden_size), _promo_size(init_promo_size), _survivor_size(init_survivor_size), _gc_pause_goal_sec(gc_pause_goal_sec), _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))), _gc_time_limit_exceeded(false), _print_gc_time_limit_would_be_exceeded(false), _gc_time_limit_count(0), _latest_minor_mutator_interval_seconds(0), _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0), _young_gen_change_for_minor_throughput(0), _old_gen_change_for_major_throughput(0) { _avg_minor_pause = new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding); _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight); _avg_minor_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight); _avg_major_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight); _avg_young_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); _avg_old_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); _avg_eden_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); _avg_survived = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight, SurvivorPadding); _avg_pretenured = new AdaptivePaddedNoZeroDevAverage( AdaptiveSizePolicyWeight, SurvivorPadding); _minor_pause_old_estimator = new LinearLeastSquareFit(AdaptiveSizePolicyWeight); _minor_pause_young_estimator = new LinearLeastSquareFit(AdaptiveSizePolicyWeight); _minor_collection_estimator = new LinearLeastSquareFit(AdaptiveSizePolicyWeight); _major_collection_estimator = new LinearLeastSquareFit(AdaptiveSizePolicyWeight); // Start the timers _minor_timer.start(); _young_gen_policy_is_ready = false; } bool AdaptiveSizePolicy::tenuring_threshold_change() const { return decrement_tenuring_threshold_for_gc_cost() || increment_tenuring_threshold_for_gc_cost() || decrement_tenuring_threshold_for_survivor_limit(); } void AdaptiveSizePolicy::minor_collection_begin() { // Update the interval time _minor_timer.stop(); // Save most recent collection time _latest_minor_mutator_interval_seconds = _minor_timer.seconds(); _minor_timer.reset(); _minor_timer.start(); } void AdaptiveSizePolicy::update_minor_pause_young_estimator( double minor_pause_in_ms) { double eden_size_in_mbytes = ((double)_eden_size)/((double)M); _minor_pause_young_estimator->update(eden_size_in_mbytes, minor_pause_in_ms); } void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) { // Update the pause time. _minor_timer.stop(); if (gc_cause != GCCause::_java_lang_system_gc || UseAdaptiveSizePolicyWithSystemGC) { double minor_pause_in_seconds = _minor_timer.seconds(); double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS; // Sample for performance counter _avg_minor_pause->sample(minor_pause_in_seconds); // Cost of collection (unit-less) double collection_cost = 0.0; if ((_latest_minor_mutator_interval_seconds > 0.0) && (minor_pause_in_seconds > 0.0)) { double interval_in_seconds = _latest_minor_mutator_interval_seconds + minor_pause_in_seconds; collection_cost = minor_pause_in_seconds / interval_in_seconds; _avg_minor_gc_cost->sample(collection_cost); // Sample for performance counter _avg_minor_interval->sample(interval_in_seconds); } // The policy does not have enough data until at least some // minor collections have been done. _young_gen_policy_is_ready = (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold); // Calculate variables used to estimate pause time vs. gen sizes double eden_size_in_mbytes = ((double)_eden_size)/((double)M); update_minor_pause_young_estimator(minor_pause_in_ms); update_minor_pause_old_estimator(minor_pause_in_ms); if (PrintAdaptiveSizePolicy && Verbose) { gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: " "minor gc cost: %f average: %f", collection_cost, _avg_minor_gc_cost->average()); gclog_or_tty->print_cr(" minor pause: %f minor period %f", minor_pause_in_ms, _latest_minor_mutator_interval_seconds * MILLIUNITS); } // Calculate variable used to estimate collection cost vs. gen sizes assert(collection_cost >= 0.0, "Expected to be non-negative"); _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost); } // Interval times use this timer to measure the mutator time. // Reset the timer after the GC pause. _minor_timer.reset(); _minor_timer.start(); } size_t AdaptiveSizePolicy::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 AdaptiveSizePolicy::eden_increment(size_t cur_eden) { return eden_increment(cur_eden, YoungGenerationSizeIncrement); } size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) { size_t eden_heap_delta = eden_increment(cur_eden) / AdaptiveSizeDecrementScaleFactor; return eden_heap_delta; } size_t AdaptiveSizePolicy::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 AdaptiveSizePolicy::promo_increment(size_t cur_promo) { return promo_increment(cur_promo, TenuredGenerationSizeIncrement); } size_t AdaptiveSizePolicy::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; } double AdaptiveSizePolicy::time_since_major_gc() const { _major_timer.stop(); double result = _major_timer.seconds(); _major_timer.start(); return result; } // Linear decay of major gc cost double AdaptiveSizePolicy::decaying_major_gc_cost() const { double major_interval = major_gc_interval_average_for_decay(); double major_gc_cost_average = major_gc_cost(); double decayed_major_gc_cost = major_gc_cost_average; if(time_since_major_gc() > 0.0) { decayed_major_gc_cost = major_gc_cost() * (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval) / time_since_major_gc(); } // The decayed cost should always be smaller than the // average cost but the vagaries of finite arithmetic could // produce a larger value in decayed_major_gc_cost so protect // against that. return MIN2(major_gc_cost_average, decayed_major_gc_cost); } // Use a value of the major gc cost that has been decayed // by the factor // // average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale / // time-since-last-major-gc // // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale // is less than time-since-last-major-gc. // // In cases where there are initial major gc's that // are of a relatively high cost but no later major // gc's, the total gc cost can remain high because // the major gc cost remains unchanged (since there are no major // gc's). In such a situation the value of the unchanging // major gc cost can keep the mutator throughput below // the goal when in fact the major gc cost is becoming diminishingly // small. Use the decaying gc cost only to decide whether to // adjust for throughput. Using it also to determine the adjustment // to be made for throughput also seems reasonable but there is // no test case to use to decide if it is the right thing to do // don't do it yet. double AdaptiveSizePolicy::decaying_gc_cost() const { double decayed_major_gc_cost = major_gc_cost(); double avg_major_interval = major_gc_interval_average_for_decay(); if (UseAdaptiveSizeDecayMajorGCCost && (AdaptiveSizeMajorGCDecayTimeScale > 0) && (avg_major_interval > 0.00)) { double time_since_last_major_gc = time_since_major_gc(); // Decay the major gc cost? if (time_since_last_major_gc > ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) { // Decay using the time-since-last-major-gc decayed_major_gc_cost = decaying_major_gc_cost(); if (PrintGCDetails && Verbose) { gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:" " %f time since last major gc: %f", avg_major_interval, time_since_last_major_gc); gclog_or_tty->print_cr(" major gc cost: %f decayed major gc cost: %f", major_gc_cost(), decayed_major_gc_cost); } } } double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost()); return result; } void AdaptiveSizePolicy::clear_generation_free_space_flags() { set_change_young_gen_for_min_pauses(0); set_change_old_gen_for_maj_pauses(0); set_change_old_gen_for_throughput(0); set_change_young_gen_for_throughput(0); set_decrease_for_footprint(0); set_decide_at_full_gc(0); } // Printing bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const { // Should only be used with adaptive size policy turned on. // Otherwise, there may be variables that are undefined. if (!UseAdaptiveSizePolicy) return false; // Print goal for which action is needed. char* action = NULL; bool change_for_pause = false; if ((change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) || (change_young_gen_for_min_pauses() == decrease_young_gen_for_min_pauses_true)) { action = (char*) " *** pause time goal ***"; change_for_pause = true; } else if ((change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) || (change_young_gen_for_throughput() == increase_young_gen_for_througput_true)) { action = (char*) " *** throughput goal ***"; } else if (decrease_for_footprint()) { action = (char*) " *** reduced footprint ***"; } else { // No actions were taken. This can legitimately be the // situation if not enough data has been gathered to make // decisions. return false; } // Pauses // Currently the size of the old gen is only adjusted to // change the major pause times. char* young_gen_action = NULL; char* tenured_gen_action = NULL; char* shrink_msg = (char*) "(attempted to shrink)"; char* grow_msg = (char*) "(attempted to grow)"; char* no_change_msg = (char*) "(no change)"; if (change_young_gen_for_min_pauses() == decrease_young_gen_for_min_pauses_true) { young_gen_action = shrink_msg; } else if (change_for_pause) { young_gen_action = no_change_msg; } if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) { tenured_gen_action = shrink_msg; } else if (change_for_pause) { tenured_gen_action = no_change_msg; } // Throughput if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) { assert(change_young_gen_for_throughput() == increase_young_gen_for_througput_true, "Both generations should be growing"); young_gen_action = grow_msg; tenured_gen_action = grow_msg; } else if (change_young_gen_for_throughput() == increase_young_gen_for_througput_true) { // Only the young generation may grow at start up (before // enough full collections have been done to grow the old generation). young_gen_action = grow_msg; tenured_gen_action = no_change_msg; } // Minimum footprint if (decrease_for_footprint() != 0) { young_gen_action = shrink_msg; tenured_gen_action = shrink_msg; } st->print_cr(" UseAdaptiveSizePolicy actions to meet %s", action); st->print_cr(" GC overhead (%%)"); st->print_cr(" Young generation: %7.2f\t %s", 100.0 * avg_minor_gc_cost()->average(), young_gen_action); st->print_cr(" Tenured generation: %7.2f\t %s", 100.0 * avg_major_gc_cost()->average(), tenured_gen_action); return true; } bool AdaptiveSizePolicy::print_adaptive_size_policy_on( outputStream* st, int tenuring_threshold_arg) const { if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) { return false; } // Tenuring threshold bool tenuring_threshold_changed = true; if (decrement_tenuring_threshold_for_survivor_limit()) { st->print(" Tenuring threshold: (attempted to decrease to avoid" " survivor space overflow) = "); } else if (decrement_tenuring_threshold_for_gc_cost()) { st->print(" Tenuring threshold: (attempted to decrease to balance" " GC costs) = "); } else if (increment_tenuring_threshold_for_gc_cost()) { st->print(" Tenuring threshold: (attempted to increase to balance" " GC costs) = "); } else { tenuring_threshold_changed = false; assert(!tenuring_threshold_change(), "(no change was attempted)"); } if (tenuring_threshold_changed) { st->print_cr("%d", tenuring_threshold_arg); } return true; }