--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shared/adaptiveSizePolicy.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,631 @@
+/*
+ * Copyright (c) 2004, 2016, 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/shared/adaptiveSizePolicy.hpp"
+#include "gc/shared/collectorPolicy.hpp"
+#include "gc/shared/gcCause.hpp"
+#include "gc/shared/workgroup.hpp"
+#include "logging/log.hpp"
+#include "runtime/timer.hpp"
+#include "utilities/ostream.hpp"
+elapsedTimer AdaptiveSizePolicy::_minor_timer;
+elapsedTimer AdaptiveSizePolicy::_major_timer;
+bool AdaptiveSizePolicy::_debug_perturbation = false;
+
+// 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_overhead_limit_exceeded(false),
+ _print_gc_overhead_limit_would_be_exceeded(false),
+ _gc_overhead_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) {
+ assert(AdaptiveSizePolicyGCTimeLimitThreshold > 0,
+ "No opportunity to clear SoftReferences before GC overhead limit");
+ _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;
+}
+
+// If the number of GC threads was set on the command line,
+// use it.
+// Else
+// Calculate the number of GC threads based on the number of Java threads.
+// Calculate the number of GC threads based on the size of the heap.
+// Use the larger.
+
+uint AdaptiveSizePolicy::calc_default_active_workers(uintx total_workers,
+ const uintx min_workers,
+ uintx active_workers,
+ uintx application_workers) {
+ // If the user has specifically set the number of
+ // GC threads, use them.
+
+ // If the user has turned off using a dynamic number of GC threads
+ // or the users has requested a specific number, set the active
+ // number of workers to all the workers.
+
+ uintx new_active_workers = total_workers;
+ uintx prev_active_workers = active_workers;
+ uintx active_workers_by_JT = 0;
+ uintx active_workers_by_heap_size = 0;
+
+ // Always use at least min_workers but use up to
+ // GCThreadsPerJavaThreads * application threads.
+ active_workers_by_JT =
+ MAX2((uintx) GCWorkersPerJavaThread * application_workers,
+ min_workers);
+
+ // Choose a number of GC threads based on the current size
+ // of the heap. This may be complicated because the size of
+ // the heap depends on factors such as the throughput goal.
+ // Still a large heap should be collected by more GC threads.
+ active_workers_by_heap_size =
+ MAX2((size_t) 2U, Universe::heap()->capacity() / HeapSizePerGCThread);
+
+ uintx max_active_workers =
+ MAX2(active_workers_by_JT, active_workers_by_heap_size);
+
+ new_active_workers = MIN2(max_active_workers, (uintx) total_workers);
+
+ // Increase GC workers instantly but decrease them more
+ // slowly.
+ if (new_active_workers < prev_active_workers) {
+ new_active_workers =
+ MAX2(min_workers, (prev_active_workers + new_active_workers) / 2);
+ }
+
+ // Check once more that the number of workers is within the limits.
+ assert(min_workers <= total_workers, "Minimum workers not consistent with total workers");
+ assert(new_active_workers >= min_workers, "Minimum workers not observed");
+ assert(new_active_workers <= total_workers, "Total workers not observed");
+
+ if (ForceDynamicNumberOfGCThreads) {
+ // Assume this is debugging and jiggle the number of GC threads.
+ if (new_active_workers == prev_active_workers) {
+ if (new_active_workers < total_workers) {
+ new_active_workers++;
+ } else if (new_active_workers > min_workers) {
+ new_active_workers--;
+ }
+ }
+ if (new_active_workers == total_workers) {
+ if (_debug_perturbation) {
+ new_active_workers = min_workers;
+ }
+ _debug_perturbation = !_debug_perturbation;
+ }
+ assert((new_active_workers <= ParallelGCThreads) &&
+ (new_active_workers >= min_workers),
+ "Jiggled active workers too much");
+ }
+
+ log_trace(gc, task)("GCTaskManager::calc_default_active_workers() : "
+ "active_workers(): " UINTX_FORMAT " new_active_workers: " UINTX_FORMAT " "
+ "prev_active_workers: " UINTX_FORMAT "\n"
+ " active_workers_by_JT: " UINTX_FORMAT " active_workers_by_heap_size: " UINTX_FORMAT,
+ active_workers, new_active_workers, prev_active_workers,
+ active_workers_by_JT, active_workers_by_heap_size);
+ assert(new_active_workers > 0, "Always need at least 1");
+ return new_active_workers;
+}
+
+uint AdaptiveSizePolicy::calc_active_workers(uintx total_workers,
+ uintx active_workers,
+ uintx application_workers) {
+ // If the user has specifically set the number of
+ // GC threads, use them.
+
+ // If the user has turned off using a dynamic number of GC threads
+ // or the users has requested a specific number, set the active
+ // number of workers to all the workers.
+
+ uint new_active_workers;
+ if (!UseDynamicNumberOfGCThreads ||
+ (!FLAG_IS_DEFAULT(ParallelGCThreads) && !ForceDynamicNumberOfGCThreads)) {
+ new_active_workers = total_workers;
+ } else {
+ uintx min_workers = (total_workers == 1) ? 1 : 2;
+ new_active_workers = calc_default_active_workers(total_workers,
+ min_workers,
+ active_workers,
+ application_workers);
+ }
+ assert(new_active_workers > 0, "Always need at least 1");
+ return new_active_workers;
+}
+
+uint AdaptiveSizePolicy::calc_active_conc_workers(uintx total_workers,
+ uintx active_workers,
+ uintx application_workers) {
+ if (!UseDynamicNumberOfGCThreads ||
+ (!FLAG_IS_DEFAULT(ConcGCThreads) && !ForceDynamicNumberOfGCThreads)) {
+ return ConcGCThreads;
+ } else {
+ uint no_of_gc_threads = calc_default_active_workers(total_workers,
+ 1, /* Minimum number of workers */
+ active_workers,
+ application_workers);
+ return no_of_gc_threads;
+ }
+}
+
+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 (!GCCause::is_user_requested_gc(gc_cause) ||
+ 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
+ // young 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);
+
+ log_trace(gc, ergo)("AdaptiveSizePolicy::minor_collection_end: minor gc cost: %f average: %f",
+ collection_cost, _avg_minor_gc_cost->average());
+ log_trace(gc, ergo)(" 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();
+ log_trace(gc, ergo)("decaying_gc_cost: major interval average: %f time since last major gc: %f",
+ avg_major_interval, time_since_last_major_gc);
+ log_trace(gc, ergo)(" 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);
+}
+
+void AdaptiveSizePolicy::check_gc_overhead_limit(
+ size_t young_live,
+ size_t eden_live,
+ size_t max_old_gen_size,
+ size_t max_eden_size,
+ bool is_full_gc,
+ GCCause::Cause gc_cause,
+ CollectorPolicy* collector_policy) {
+
+ // Ignore explicit GC's. Exiting here does not set the flag and
+ // does not reset the count. Updating of the averages for system
+ // GC's is still controlled by UseAdaptiveSizePolicyWithSystemGC.
+ if (GCCause::is_user_requested_gc(gc_cause) ||
+ GCCause::is_serviceability_requested_gc(gc_cause)) {
+ return;
+ }
+ // 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 behavior.
+ const size_t live_in_eden =
+ MIN2(eden_live, (size_t) avg_eden_live()->average());
+ const size_t free_in_eden = max_eden_size > live_in_eden ?
+ max_eden_size - live_in_eden : 0;
+ const size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
+ 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);
+ const double mem_free_old_limit = max_old_gen_size * (GCHeapFreeLimit/100.0);
+ const double mem_free_eden_limit = max_eden_size * (GCHeapFreeLimit/100.0);
+ const double gc_cost_limit = GCTimeLimit/100.0;
+ 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);
+
+
+ log_trace(gc, ergo)(
+ "PSAdaptiveSizePolicy::check_gc_overhead_limit:"
+ " promo_limit: " SIZE_FORMAT
+ " max_eden_size: " 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, max_eden_size, total_free_limit,
+ max_old_gen_size, max_eden_size,
+ (size_t) mem_free_limit);
+
+ bool print_gc_overhead_limit_would_be_exceeded = false;
+ if (is_full_gc) {
+ if (gc_cost() > gc_cost_limit &&
+ free_in_old_gen < (size_t) mem_free_old_limit &&
+ free_in_eden < (size_t) mem_free_eden_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.
+ // At this point the GC overhead limit is being exceeded.
+ inc_gc_overhead_limit_count();
+ if (UseGCOverheadLimit) {
+ if (gc_overhead_limit_count() >=
+ AdaptiveSizePolicyGCTimeLimitThreshold){
+ // All conditions have been met for throwing an out-of-memory
+ set_gc_overhead_limit_exceeded(true);
+ // Avoid consecutive OOM due to the gc time limit by resetting
+ // the counter.
+ reset_gc_overhead_limit_count();
+ } else {
+ // The required consecutive collections which exceed the
+ // GC time limit may or may not have been reached. We
+ // are approaching that condition and so as not to
+ // throw an out-of-memory before all SoftRef's have been
+ // cleared, set _should_clear_all_soft_refs in CollectorPolicy.
+ // The clearing will be done on the next GC.
+ bool near_limit = gc_overhead_limit_near();
+ if (near_limit) {
+ collector_policy->set_should_clear_all_soft_refs(true);
+ log_trace(gc, ergo)("Nearing GC overhead limit, will be clearing all SoftReference");
+ }
+ }
+ }
+ // Set this even when the overhead limit will not
+ // cause an out-of-memory. Diagnostic message indicating
+ // that the overhead limit is being exceeded is sometimes
+ // printed.
+ print_gc_overhead_limit_would_be_exceeded = true;
+
+ } else {
+ // Did not exceed overhead limits
+ reset_gc_overhead_limit_count();
+ }
+ }
+
+ if (UseGCOverheadLimit) {
+ if (gc_overhead_limit_exceeded()) {
+ log_trace(gc, ergo)("GC is exceeding overhead limit of " UINTX_FORMAT "%%", GCTimeLimit);
+ reset_gc_overhead_limit_count();
+ } else if (print_gc_overhead_limit_would_be_exceeded) {
+ assert(gc_overhead_limit_count() > 0, "Should not be printing");
+ log_trace(gc, ergo)("GC would exceed overhead limit of " UINTX_FORMAT "%% %d consecutive time(s)",
+ GCTimeLimit, gc_overhead_limit_count());
+ }
+ }
+}
+// Printing
+
+bool AdaptiveSizePolicy::print() const {
+ assert(UseAdaptiveSizePolicy, "UseAdaptiveSizePolicy need to be enabled.");
+
+ if (!log_is_enabled(Debug, gc, ergo)) {
+ 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;
+ }
+
+ log_debug(gc, ergo)("UseAdaptiveSizePolicy actions to meet %s", action);
+ log_debug(gc, ergo)(" GC overhead (%%)");
+ log_debug(gc, ergo)(" Young generation: %7.2f\t %s",
+ 100.0 * avg_minor_gc_cost()->average(), young_gen_action);
+ log_debug(gc, ergo)(" Tenured generation: %7.2f\t %s",
+ 100.0 * avg_major_gc_cost()->average(), tenured_gen_action);
+ return true;
+}
+
+void AdaptiveSizePolicy::print_tenuring_threshold( uint new_tenuring_threshold_arg) const {
+ // Tenuring threshold
+ if (decrement_tenuring_threshold_for_survivor_limit()) {
+ log_debug(gc, ergo)("Tenuring threshold: (attempted to decrease to avoid survivor space overflow) = %u", new_tenuring_threshold_arg);
+ } else if (decrement_tenuring_threshold_for_gc_cost()) {
+ log_debug(gc, ergo)("Tenuring threshold: (attempted to decrease to balance GC costs) = %u", new_tenuring_threshold_arg);
+ } else if (increment_tenuring_threshold_for_gc_cost()) {
+ log_debug(gc, ergo)("Tenuring threshold: (attempted to increase to balance GC costs) = %u", new_tenuring_threshold_arg);
+ } else {
+ assert(!tenuring_threshold_change(), "(no change was attempted)");
+ }
+}