duke@435: /* drchase@6680: * Copyright (c) 2004, 2014, Oracle and/or its affiliates. All rights reserved. duke@435: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. duke@435: * duke@435: * This code is free software; you can redistribute it and/or modify it duke@435: * under the terms of the GNU General Public License version 2 only, as duke@435: * published by the Free Software Foundation. duke@435: * duke@435: * This code is distributed in the hope that it will be useful, but WITHOUT duke@435: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or duke@435: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License duke@435: * version 2 for more details (a copy is included in the LICENSE file that duke@435: * accompanied this code). duke@435: * duke@435: * You should have received a copy of the GNU General Public License version duke@435: * 2 along with this work; if not, write to the Free Software Foundation, duke@435: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. duke@435: * trims@1907: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA trims@1907: * or visit www.oracle.com if you need additional information or have any trims@1907: * questions. duke@435: * duke@435: */ duke@435: stefank@2314: #include "precompiled.hpp" stefank@2314: #include "gc_implementation/shared/adaptiveSizePolicy.hpp" stefank@2314: #include "gc_interface/gcCause.hpp" stefank@2314: #include "memory/collectorPolicy.hpp" stefank@2314: #include "runtime/timer.hpp" stefank@2314: #include "utilities/ostream.hpp" jmasa@3294: #include "utilities/workgroup.hpp" duke@435: elapsedTimer AdaptiveSizePolicy::_minor_timer; duke@435: elapsedTimer AdaptiveSizePolicy::_major_timer; jmasa@3294: bool AdaptiveSizePolicy::_debug_perturbation = false; duke@435: duke@435: // The throughput goal is implemented as duke@435: // _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio)) duke@435: // gc_cost_ratio is the ratio duke@435: // application cost / gc cost duke@435: // For example a gc_cost_ratio of 4 translates into a duke@435: // throughput goal of .80 duke@435: duke@435: AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size, duke@435: size_t init_promo_size, duke@435: size_t init_survivor_size, duke@435: double gc_pause_goal_sec, duke@435: uint gc_cost_ratio) : duke@435: _eden_size(init_eden_size), duke@435: _promo_size(init_promo_size), duke@435: _survivor_size(init_survivor_size), duke@435: _gc_pause_goal_sec(gc_pause_goal_sec), duke@435: _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))), jmasa@1822: _gc_overhead_limit_exceeded(false), jmasa@1822: _print_gc_overhead_limit_would_be_exceeded(false), jmasa@1822: _gc_overhead_limit_count(0), duke@435: _latest_minor_mutator_interval_seconds(0), duke@435: _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0), duke@435: _young_gen_change_for_minor_throughput(0), duke@435: _old_gen_change_for_major_throughput(0) { jmasa@1822: assert(AdaptiveSizePolicyGCTimeLimitThreshold > 0, jmasa@1822: "No opportunity to clear SoftReferences before GC overhead limit"); duke@435: _avg_minor_pause = duke@435: new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding); duke@435: _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight); duke@435: _avg_minor_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight); duke@435: _avg_major_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight); duke@435: duke@435: _avg_young_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); duke@435: _avg_old_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); duke@435: _avg_eden_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); duke@435: duke@435: _avg_survived = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight, duke@435: SurvivorPadding); duke@435: _avg_pretenured = new AdaptivePaddedNoZeroDevAverage( duke@435: AdaptiveSizePolicyWeight, duke@435: SurvivorPadding); duke@435: duke@435: _minor_pause_old_estimator = duke@435: new LinearLeastSquareFit(AdaptiveSizePolicyWeight); duke@435: _minor_pause_young_estimator = duke@435: new LinearLeastSquareFit(AdaptiveSizePolicyWeight); duke@435: _minor_collection_estimator = duke@435: new LinearLeastSquareFit(AdaptiveSizePolicyWeight); duke@435: _major_collection_estimator = duke@435: new LinearLeastSquareFit(AdaptiveSizePolicyWeight); duke@435: duke@435: // Start the timers duke@435: _minor_timer.start(); duke@435: duke@435: _young_gen_policy_is_ready = false; duke@435: } duke@435: jmasa@3294: // If the number of GC threads was set on the command line, jmasa@3294: // use it. jmasa@3294: // Else jmasa@3294: // Calculate the number of GC threads based on the number of Java threads. jmasa@3294: // Calculate the number of GC threads based on the size of the heap. jmasa@3294: // Use the larger. jmasa@3294: jmasa@3294: int AdaptiveSizePolicy::calc_default_active_workers(uintx total_workers, jmasa@3294: const uintx min_workers, jmasa@3294: uintx active_workers, jmasa@3294: uintx application_workers) { jmasa@3294: // If the user has specifically set the number of jmasa@3294: // GC threads, use them. jmasa@3294: jmasa@3294: // If the user has turned off using a dynamic number of GC threads jmasa@3294: // or the users has requested a specific number, set the active jmasa@3294: // number of workers to all the workers. jmasa@3294: jmasa@3294: uintx new_active_workers = total_workers; jmasa@3294: uintx prev_active_workers = active_workers; jmasa@3294: uintx active_workers_by_JT = 0; jmasa@3294: uintx active_workers_by_heap_size = 0; jmasa@3294: jmasa@3294: // Always use at least min_workers but use up to jmasa@3294: // GCThreadsPerJavaThreads * application threads. jmasa@3294: active_workers_by_JT = jmasa@3294: MAX2((uintx) GCWorkersPerJavaThread * application_workers, jmasa@3294: min_workers); jmasa@3294: jmasa@3294: // Choose a number of GC threads based on the current size jmasa@3294: // of the heap. This may be complicated because the size of jmasa@3294: // the heap depends on factors such as the thoughput goal. jmasa@3294: // Still a large heap should be collected by more GC threads. jmasa@3294: active_workers_by_heap_size = jmasa@3294: MAX2((size_t) 2U, Universe::heap()->capacity() / HeapSizePerGCThread); jmasa@3294: jmasa@3294: uintx max_active_workers = jmasa@3294: MAX2(active_workers_by_JT, active_workers_by_heap_size); jmasa@3294: jmasa@3294: // Limit the number of workers to the the number created, jmasa@3294: // (workers()). jmasa@3294: new_active_workers = MIN2(max_active_workers, jmasa@3294: (uintx) total_workers); jmasa@3294: jmasa@3294: // Increase GC workers instantly but decrease them more jmasa@3294: // slowly. jmasa@3294: if (new_active_workers < prev_active_workers) { jmasa@3294: new_active_workers = jmasa@3294: MAX2(min_workers, (prev_active_workers + new_active_workers) / 2); jmasa@3294: } jmasa@3294: jmasa@3294: // Check once more that the number of workers is within the limits. jmasa@3294: assert(min_workers <= total_workers, "Minimum workers not consistent with total workers"); jmasa@3294: assert(new_active_workers >= min_workers, "Minimum workers not observed"); jmasa@3294: assert(new_active_workers <= total_workers, "Total workers not observed"); jmasa@3294: jmasa@3294: if (ForceDynamicNumberOfGCThreads) { jmasa@3294: // Assume this is debugging and jiggle the number of GC threads. jmasa@3294: if (new_active_workers == prev_active_workers) { jmasa@3294: if (new_active_workers < total_workers) { jmasa@3294: new_active_workers++; jmasa@3294: } else if (new_active_workers > min_workers) { jmasa@3294: new_active_workers--; jmasa@3294: } jmasa@3294: } jmasa@3294: if (new_active_workers == total_workers) { jmasa@3294: if (_debug_perturbation) { jmasa@3294: new_active_workers = min_workers; jmasa@3294: } jmasa@3294: _debug_perturbation = !_debug_perturbation; jmasa@3294: } jmasa@3294: assert((new_active_workers <= (uintx) ParallelGCThreads) && jmasa@3294: (new_active_workers >= min_workers), jmasa@3294: "Jiggled active workers too much"); jmasa@3294: } jmasa@3294: jmasa@3294: if (TraceDynamicGCThreads) { jmasa@3294: gclog_or_tty->print_cr("GCTaskManager::calc_default_active_workers() : " jmasa@3294: "active_workers(): %d new_acitve_workers: %d " jmasa@3294: "prev_active_workers: %d\n" jmasa@3294: " active_workers_by_JT: %d active_workers_by_heap_size: %d", drchase@6680: (int) active_workers, (int) new_active_workers, (int) prev_active_workers, drchase@6680: (int) active_workers_by_JT, (int) active_workers_by_heap_size); jmasa@3294: } jmasa@3294: assert(new_active_workers > 0, "Always need at least 1"); jmasa@3294: return new_active_workers; jmasa@3294: } jmasa@3294: jmasa@3294: int AdaptiveSizePolicy::calc_active_workers(uintx total_workers, jmasa@3294: uintx active_workers, jmasa@3294: uintx application_workers) { jmasa@3294: // If the user has specifically set the number of jmasa@3294: // GC threads, use them. jmasa@3294: jmasa@3294: // If the user has turned off using a dynamic number of GC threads jmasa@3294: // or the users has requested a specific number, set the active jmasa@3294: // number of workers to all the workers. jmasa@3294: jmasa@3294: int new_active_workers; jmasa@3294: if (!UseDynamicNumberOfGCThreads || jmasa@3294: (!FLAG_IS_DEFAULT(ParallelGCThreads) && !ForceDynamicNumberOfGCThreads)) { jmasa@3294: new_active_workers = total_workers; jmasa@3294: } else { jmasa@3294: new_active_workers = calc_default_active_workers(total_workers, jmasa@3294: 2, /* Minimum number of workers */ jmasa@3294: active_workers, jmasa@3294: application_workers); jmasa@3294: } jmasa@3294: assert(new_active_workers > 0, "Always need at least 1"); jmasa@3294: return new_active_workers; jmasa@3294: } jmasa@3294: jmasa@3294: int AdaptiveSizePolicy::calc_active_conc_workers(uintx total_workers, jmasa@3294: uintx active_workers, jmasa@3294: uintx application_workers) { jmasa@3294: if (!UseDynamicNumberOfGCThreads || jmasa@3294: (!FLAG_IS_DEFAULT(ConcGCThreads) && !ForceDynamicNumberOfGCThreads)) { jmasa@3294: return ConcGCThreads; jmasa@3294: } else { jmasa@3294: int no_of_gc_threads = calc_default_active_workers( jmasa@3294: total_workers, jmasa@3294: 1, /* Minimum number of workers */ jmasa@3294: active_workers, jmasa@3294: application_workers); jmasa@3294: return no_of_gc_threads; jmasa@3294: } jmasa@3294: } jmasa@3294: duke@435: bool AdaptiveSizePolicy::tenuring_threshold_change() const { duke@435: return decrement_tenuring_threshold_for_gc_cost() || duke@435: increment_tenuring_threshold_for_gc_cost() || duke@435: decrement_tenuring_threshold_for_survivor_limit(); duke@435: } duke@435: duke@435: void AdaptiveSizePolicy::minor_collection_begin() { duke@435: // Update the interval time duke@435: _minor_timer.stop(); duke@435: // Save most recent collection time duke@435: _latest_minor_mutator_interval_seconds = _minor_timer.seconds(); duke@435: _minor_timer.reset(); duke@435: _minor_timer.start(); duke@435: } duke@435: duke@435: void AdaptiveSizePolicy::update_minor_pause_young_estimator( duke@435: double minor_pause_in_ms) { duke@435: double eden_size_in_mbytes = ((double)_eden_size)/((double)M); duke@435: _minor_pause_young_estimator->update(eden_size_in_mbytes, duke@435: minor_pause_in_ms); duke@435: } duke@435: duke@435: void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) { duke@435: // Update the pause time. duke@435: _minor_timer.stop(); duke@435: duke@435: if (gc_cause != GCCause::_java_lang_system_gc || duke@435: UseAdaptiveSizePolicyWithSystemGC) { duke@435: double minor_pause_in_seconds = _minor_timer.seconds(); duke@435: double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS; duke@435: duke@435: // Sample for performance counter duke@435: _avg_minor_pause->sample(minor_pause_in_seconds); duke@435: duke@435: // Cost of collection (unit-less) duke@435: double collection_cost = 0.0; duke@435: if ((_latest_minor_mutator_interval_seconds > 0.0) && duke@435: (minor_pause_in_seconds > 0.0)) { duke@435: double interval_in_seconds = duke@435: _latest_minor_mutator_interval_seconds + minor_pause_in_seconds; duke@435: collection_cost = duke@435: minor_pause_in_seconds / interval_in_seconds; duke@435: _avg_minor_gc_cost->sample(collection_cost); duke@435: // Sample for performance counter duke@435: _avg_minor_interval->sample(interval_in_seconds); duke@435: } duke@435: duke@435: // The policy does not have enough data until at least some duke@435: // minor collections have been done. duke@435: _young_gen_policy_is_ready = duke@435: (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold); duke@435: duke@435: // Calculate variables used to estimate pause time vs. gen sizes duke@435: double eden_size_in_mbytes = ((double)_eden_size)/((double)M); duke@435: update_minor_pause_young_estimator(minor_pause_in_ms); duke@435: update_minor_pause_old_estimator(minor_pause_in_ms); duke@435: duke@435: if (PrintAdaptiveSizePolicy && Verbose) { duke@435: gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: " duke@435: "minor gc cost: %f average: %f", collection_cost, duke@435: _avg_minor_gc_cost->average()); duke@435: gclog_or_tty->print_cr(" minor pause: %f minor period %f", duke@435: minor_pause_in_ms, duke@435: _latest_minor_mutator_interval_seconds * MILLIUNITS); duke@435: } duke@435: duke@435: // Calculate variable used to estimate collection cost vs. gen sizes duke@435: assert(collection_cost >= 0.0, "Expected to be non-negative"); duke@435: _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost); duke@435: } duke@435: duke@435: // Interval times use this timer to measure the mutator time. duke@435: // Reset the timer after the GC pause. duke@435: _minor_timer.reset(); duke@435: _minor_timer.start(); duke@435: } duke@435: duke@435: size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden, duke@435: uint percent_change) { duke@435: size_t eden_heap_delta; duke@435: eden_heap_delta = cur_eden / 100 * percent_change; duke@435: return eden_heap_delta; duke@435: } duke@435: duke@435: size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) { duke@435: return eden_increment(cur_eden, YoungGenerationSizeIncrement); duke@435: } duke@435: duke@435: size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) { duke@435: size_t eden_heap_delta = eden_increment(cur_eden) / duke@435: AdaptiveSizeDecrementScaleFactor; duke@435: return eden_heap_delta; duke@435: } duke@435: duke@435: size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo, duke@435: uint percent_change) { duke@435: size_t promo_heap_delta; duke@435: promo_heap_delta = cur_promo / 100 * percent_change; duke@435: return promo_heap_delta; duke@435: } duke@435: duke@435: size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) { duke@435: return promo_increment(cur_promo, TenuredGenerationSizeIncrement); duke@435: } duke@435: duke@435: size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) { duke@435: size_t promo_heap_delta = promo_increment(cur_promo); duke@435: promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor; duke@435: return promo_heap_delta; duke@435: } duke@435: duke@435: double AdaptiveSizePolicy::time_since_major_gc() const { duke@435: _major_timer.stop(); duke@435: double result = _major_timer.seconds(); duke@435: _major_timer.start(); duke@435: return result; duke@435: } duke@435: duke@435: // Linear decay of major gc cost duke@435: double AdaptiveSizePolicy::decaying_major_gc_cost() const { duke@435: double major_interval = major_gc_interval_average_for_decay(); duke@435: double major_gc_cost_average = major_gc_cost(); duke@435: double decayed_major_gc_cost = major_gc_cost_average; duke@435: if(time_since_major_gc() > 0.0) { duke@435: decayed_major_gc_cost = major_gc_cost() * duke@435: (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval) duke@435: / time_since_major_gc(); duke@435: } duke@435: duke@435: // The decayed cost should always be smaller than the duke@435: // average cost but the vagaries of finite arithmetic could duke@435: // produce a larger value in decayed_major_gc_cost so protect duke@435: // against that. duke@435: return MIN2(major_gc_cost_average, decayed_major_gc_cost); duke@435: } duke@435: duke@435: // Use a value of the major gc cost that has been decayed duke@435: // by the factor duke@435: // duke@435: // average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale / duke@435: // time-since-last-major-gc duke@435: // duke@435: // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale duke@435: // is less than time-since-last-major-gc. duke@435: // duke@435: // In cases where there are initial major gc's that duke@435: // are of a relatively high cost but no later major duke@435: // gc's, the total gc cost can remain high because duke@435: // the major gc cost remains unchanged (since there are no major duke@435: // gc's). In such a situation the value of the unchanging duke@435: // major gc cost can keep the mutator throughput below duke@435: // the goal when in fact the major gc cost is becoming diminishingly duke@435: // small. Use the decaying gc cost only to decide whether to duke@435: // adjust for throughput. Using it also to determine the adjustment duke@435: // to be made for throughput also seems reasonable but there is duke@435: // no test case to use to decide if it is the right thing to do duke@435: // don't do it yet. duke@435: duke@435: double AdaptiveSizePolicy::decaying_gc_cost() const { duke@435: double decayed_major_gc_cost = major_gc_cost(); duke@435: double avg_major_interval = major_gc_interval_average_for_decay(); duke@435: if (UseAdaptiveSizeDecayMajorGCCost && duke@435: (AdaptiveSizeMajorGCDecayTimeScale > 0) && duke@435: (avg_major_interval > 0.00)) { duke@435: double time_since_last_major_gc = time_since_major_gc(); duke@435: duke@435: // Decay the major gc cost? duke@435: if (time_since_last_major_gc > duke@435: ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) { duke@435: duke@435: // Decay using the time-since-last-major-gc duke@435: decayed_major_gc_cost = decaying_major_gc_cost(); duke@435: if (PrintGCDetails && Verbose) { duke@435: gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:" duke@435: " %f time since last major gc: %f", duke@435: avg_major_interval, time_since_last_major_gc); duke@435: gclog_or_tty->print_cr(" major gc cost: %f decayed major gc cost: %f", duke@435: major_gc_cost(), decayed_major_gc_cost); duke@435: } duke@435: } duke@435: } duke@435: double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost()); duke@435: return result; duke@435: } duke@435: duke@435: duke@435: void AdaptiveSizePolicy::clear_generation_free_space_flags() { duke@435: set_change_young_gen_for_min_pauses(0); duke@435: set_change_old_gen_for_maj_pauses(0); duke@435: duke@435: set_change_old_gen_for_throughput(0); duke@435: set_change_young_gen_for_throughput(0); duke@435: set_decrease_for_footprint(0); duke@435: set_decide_at_full_gc(0); duke@435: } duke@435: jmasa@1822: void AdaptiveSizePolicy::check_gc_overhead_limit( jmasa@1822: size_t young_live, jmasa@1822: size_t eden_live, jmasa@1822: size_t max_old_gen_size, jmasa@1822: size_t max_eden_size, jmasa@1822: bool is_full_gc, jmasa@1822: GCCause::Cause gc_cause, jmasa@1822: CollectorPolicy* collector_policy) { jmasa@1822: jmasa@1822: // Ignore explicit GC's. Exiting here does not set the flag and jmasa@1822: // does not reset the count. Updating of the averages for system jmasa@1822: // GC's is still controlled by UseAdaptiveSizePolicyWithSystemGC. jmasa@1822: if (GCCause::is_user_requested_gc(gc_cause) || jmasa@1822: GCCause::is_serviceability_requested_gc(gc_cause)) { jmasa@1822: return; jmasa@1822: } jmasa@1822: // eden_limit is the upper limit on the size of eden based on jmasa@1822: // the maximum size of the young generation and the sizes jmasa@1822: // of the survivor space. jmasa@1822: // The question being asked is whether the gc costs are high jmasa@1822: // and the space being recovered by a collection is low. jmasa@1822: // free_in_young_gen is the free space in the young generation jmasa@1822: // after a collection and promo_live is the free space in the old jmasa@1822: // generation after a collection. jmasa@1822: // jmasa@1822: // Use the minimum of the current value of the live in the jmasa@1822: // young gen or the average of the live in the young gen. jmasa@1822: // If the current value drops quickly, that should be taken jmasa@1822: // into account (i.e., don't trigger if the amount of free jmasa@1822: // space has suddenly jumped up). If the current is much jmasa@1822: // higher than the average, use the average since it represents jmasa@1822: // the longer term behavor. jmasa@1822: const size_t live_in_eden = jmasa@1822: MIN2(eden_live, (size_t) avg_eden_live()->average()); jmasa@1822: const size_t free_in_eden = max_eden_size > live_in_eden ? jmasa@1822: max_eden_size - live_in_eden : 0; jmasa@1822: const size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average()); jmasa@1822: const size_t total_free_limit = free_in_old_gen + free_in_eden; jmasa@1822: const size_t total_mem = max_old_gen_size + max_eden_size; jmasa@1822: const double mem_free_limit = total_mem * (GCHeapFreeLimit/100.0); jmasa@1822: const double mem_free_old_limit = max_old_gen_size * (GCHeapFreeLimit/100.0); jmasa@1822: const double mem_free_eden_limit = max_eden_size * (GCHeapFreeLimit/100.0); jmasa@1822: const double gc_cost_limit = GCTimeLimit/100.0; jmasa@1822: size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average()); jmasa@1822: // But don't force a promo size below the current promo size. Otherwise, jmasa@1822: // the promo size will shrink for no good reason. jmasa@1822: promo_limit = MAX2(promo_limit, _promo_size); jmasa@1822: jmasa@1822: jmasa@1822: if (PrintAdaptiveSizePolicy && (Verbose || jmasa@1822: (free_in_old_gen < (size_t) mem_free_old_limit && jmasa@1822: free_in_eden < (size_t) mem_free_eden_limit))) { jmasa@1822: gclog_or_tty->print_cr( tamao@5192: "PSAdaptiveSizePolicy::check_gc_overhead_limit:" jmasa@1822: " promo_limit: " SIZE_FORMAT jmasa@1822: " max_eden_size: " SIZE_FORMAT jmasa@1822: " total_free_limit: " SIZE_FORMAT jmasa@1822: " max_old_gen_size: " SIZE_FORMAT jmasa@1822: " max_eden_size: " SIZE_FORMAT jmasa@1822: " mem_free_limit: " SIZE_FORMAT, jmasa@1822: promo_limit, max_eden_size, total_free_limit, jmasa@1822: max_old_gen_size, max_eden_size, jmasa@1822: (size_t) mem_free_limit); jmasa@1822: } jmasa@1822: jmasa@1822: bool print_gc_overhead_limit_would_be_exceeded = false; jmasa@1822: if (is_full_gc) { jmasa@1822: if (gc_cost() > gc_cost_limit && jmasa@1822: free_in_old_gen < (size_t) mem_free_old_limit && jmasa@1822: free_in_eden < (size_t) mem_free_eden_limit) { jmasa@1822: // Collections, on average, are taking too much time, and jmasa@1822: // gc_cost() > gc_cost_limit jmasa@1822: // we have too little space available after a full gc. jmasa@1822: // total_free_limit < mem_free_limit jmasa@1822: // where jmasa@1822: // total_free_limit is the free space available in jmasa@1822: // both generations jmasa@1822: // total_mem is the total space available for allocation jmasa@1822: // in both generations (survivor spaces are not included jmasa@1822: // just as they are not included in eden_limit). jmasa@1822: // mem_free_limit is a fraction of total_mem judged to be an jmasa@1822: // acceptable amount that is still unused. jmasa@1822: // The heap can ask for the value of this variable when deciding jmasa@1822: // whether to thrown an OutOfMemory error. jmasa@1822: // Note that the gc time limit test only works for the collections jmasa@1822: // of the young gen + tenured gen and not for collections of the jmasa@1822: // permanent gen. That is because the calculation of the space jmasa@1822: // freed by the collection is the free space in the young gen + jmasa@1822: // tenured gen. jmasa@1822: // At this point the GC overhead limit is being exceeded. jmasa@1822: inc_gc_overhead_limit_count(); jmasa@1822: if (UseGCOverheadLimit) { jmasa@1822: if (gc_overhead_limit_count() >= jmasa@1822: AdaptiveSizePolicyGCTimeLimitThreshold){ jmasa@1822: // All conditions have been met for throwing an out-of-memory jmasa@1822: set_gc_overhead_limit_exceeded(true); jmasa@1822: // Avoid consecutive OOM due to the gc time limit by resetting jmasa@1822: // the counter. jmasa@1822: reset_gc_overhead_limit_count(); jmasa@1822: } else { jmasa@1822: // The required consecutive collections which exceed the jmasa@1822: // GC time limit may or may not have been reached. We jmasa@1822: // are approaching that condition and so as not to jmasa@1822: // throw an out-of-memory before all SoftRef's have been jmasa@1822: // cleared, set _should_clear_all_soft_refs in CollectorPolicy. jmasa@1822: // The clearing will be done on the next GC. jmasa@1822: bool near_limit = gc_overhead_limit_near(); jmasa@1822: if (near_limit) { jmasa@1822: collector_policy->set_should_clear_all_soft_refs(true); jmasa@1822: if (PrintGCDetails && Verbose) { jmasa@1822: gclog_or_tty->print_cr(" Nearing GC overhead limit, " jmasa@1822: "will be clearing all SoftReference"); jmasa@1822: } jmasa@1822: } jmasa@1822: } jmasa@1822: } jmasa@1822: // Set this even when the overhead limit will not jmasa@1822: // cause an out-of-memory. Diagnostic message indicating jmasa@1822: // that the overhead limit is being exceeded is sometimes jmasa@1822: // printed. jmasa@1822: print_gc_overhead_limit_would_be_exceeded = true; jmasa@1822: jmasa@1822: } else { jmasa@1822: // Did not exceed overhead limits jmasa@1822: reset_gc_overhead_limit_count(); jmasa@1822: } jmasa@1822: } jmasa@1822: jmasa@1822: if (UseGCOverheadLimit && PrintGCDetails && Verbose) { jmasa@1822: if (gc_overhead_limit_exceeded()) { jmasa@1822: gclog_or_tty->print_cr(" GC is exceeding overhead limit " drchase@6680: "of %d%%", (int) GCTimeLimit); jmasa@1822: reset_gc_overhead_limit_count(); jmasa@1822: } else if (print_gc_overhead_limit_would_be_exceeded) { jmasa@1822: assert(gc_overhead_limit_count() > 0, "Should not be printing"); jmasa@1822: gclog_or_tty->print_cr(" GC would exceed overhead limit " jmasa@1822: "of %d%% %d consecutive time(s)", drchase@6680: (int) GCTimeLimit, gc_overhead_limit_count()); jmasa@1822: } jmasa@1822: } jmasa@1822: } duke@435: // Printing duke@435: duke@435: bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const { duke@435: duke@435: // Should only be used with adaptive size policy turned on. duke@435: // Otherwise, there may be variables that are undefined. duke@435: if (!UseAdaptiveSizePolicy) return false; duke@435: duke@435: // Print goal for which action is needed. duke@435: char* action = NULL; duke@435: bool change_for_pause = false; duke@435: if ((change_old_gen_for_maj_pauses() == duke@435: decrease_old_gen_for_maj_pauses_true) || duke@435: (change_young_gen_for_min_pauses() == duke@435: decrease_young_gen_for_min_pauses_true)) { duke@435: action = (char*) " *** pause time goal ***"; duke@435: change_for_pause = true; duke@435: } else if ((change_old_gen_for_throughput() == duke@435: increase_old_gen_for_throughput_true) || duke@435: (change_young_gen_for_throughput() == duke@435: increase_young_gen_for_througput_true)) { duke@435: action = (char*) " *** throughput goal ***"; duke@435: } else if (decrease_for_footprint()) { duke@435: action = (char*) " *** reduced footprint ***"; duke@435: } else { duke@435: // No actions were taken. This can legitimately be the duke@435: // situation if not enough data has been gathered to make duke@435: // decisions. duke@435: return false; duke@435: } duke@435: duke@435: // Pauses duke@435: // Currently the size of the old gen is only adjusted to duke@435: // change the major pause times. duke@435: char* young_gen_action = NULL; duke@435: char* tenured_gen_action = NULL; duke@435: duke@435: char* shrink_msg = (char*) "(attempted to shrink)"; duke@435: char* grow_msg = (char*) "(attempted to grow)"; duke@435: char* no_change_msg = (char*) "(no change)"; duke@435: if (change_young_gen_for_min_pauses() == duke@435: decrease_young_gen_for_min_pauses_true) { duke@435: young_gen_action = shrink_msg; duke@435: } else if (change_for_pause) { duke@435: young_gen_action = no_change_msg; duke@435: } duke@435: duke@435: if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) { duke@435: tenured_gen_action = shrink_msg; duke@435: } else if (change_for_pause) { duke@435: tenured_gen_action = no_change_msg; duke@435: } duke@435: duke@435: // Throughput duke@435: if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) { duke@435: assert(change_young_gen_for_throughput() == duke@435: increase_young_gen_for_througput_true, duke@435: "Both generations should be growing"); duke@435: young_gen_action = grow_msg; duke@435: tenured_gen_action = grow_msg; duke@435: } else if (change_young_gen_for_throughput() == duke@435: increase_young_gen_for_througput_true) { duke@435: // Only the young generation may grow at start up (before duke@435: // enough full collections have been done to grow the old generation). duke@435: young_gen_action = grow_msg; duke@435: tenured_gen_action = no_change_msg; duke@435: } duke@435: duke@435: // Minimum footprint duke@435: if (decrease_for_footprint() != 0) { duke@435: young_gen_action = shrink_msg; duke@435: tenured_gen_action = shrink_msg; duke@435: } duke@435: duke@435: st->print_cr(" UseAdaptiveSizePolicy actions to meet %s", action); duke@435: st->print_cr(" GC overhead (%%)"); duke@435: st->print_cr(" Young generation: %7.2f\t %s", duke@435: 100.0 * avg_minor_gc_cost()->average(), duke@435: young_gen_action); duke@435: st->print_cr(" Tenured generation: %7.2f\t %s", duke@435: 100.0 * avg_major_gc_cost()->average(), duke@435: tenured_gen_action); duke@435: return true; duke@435: } duke@435: duke@435: bool AdaptiveSizePolicy::print_adaptive_size_policy_on( duke@435: outputStream* st, jwilhelm@4129: uint tenuring_threshold_arg) const { duke@435: if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) { duke@435: return false; duke@435: } duke@435: duke@435: // Tenuring threshold duke@435: bool tenuring_threshold_changed = true; duke@435: if (decrement_tenuring_threshold_for_survivor_limit()) { duke@435: st->print(" Tenuring threshold: (attempted to decrease to avoid" duke@435: " survivor space overflow) = "); duke@435: } else if (decrement_tenuring_threshold_for_gc_cost()) { duke@435: st->print(" Tenuring threshold: (attempted to decrease to balance" duke@435: " GC costs) = "); duke@435: } else if (increment_tenuring_threshold_for_gc_cost()) { duke@435: st->print(" Tenuring threshold: (attempted to increase to balance" duke@435: " GC costs) = "); duke@435: } else { duke@435: tenuring_threshold_changed = false; duke@435: assert(!tenuring_threshold_change(), "(no change was attempted)"); duke@435: } duke@435: if (tenuring_threshold_changed) { jwilhelm@4129: st->print_cr("%u", tenuring_threshold_arg); duke@435: } duke@435: return true; duke@435: }