--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/shared/adaptiveSizePolicy.hpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,545 @@
+/*
+ * Copyright (c) 2004, 2015, 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_SHARED_ADAPTIVESIZEPOLICY_HPP
+#define SHARE_VM_GC_SHARED_ADAPTIVESIZEPOLICY_HPP
+
+#include "gc/shared/collectedHeap.hpp"
+#include "gc/shared/gcCause.hpp"
+#include "gc/shared/gcUtil.hpp"
+#include "memory/allocation.hpp"
+#include "memory/universe.hpp"
+
+// This class keeps statistical information and computes the
+// size of the heap.
+
+// Forward decls
+class elapsedTimer;
+class CollectorPolicy;
+
+class AdaptiveSizePolicy : public CHeapObj<mtGC> {
+ friend class GCAdaptivePolicyCounters;
+ friend class PSGCAdaptivePolicyCounters;
+ friend class CMSGCAdaptivePolicyCounters;
+ protected:
+
+ enum GCPolicyKind {
+ _gc_adaptive_size_policy,
+ _gc_ps_adaptive_size_policy,
+ _gc_cms_adaptive_size_policy
+ };
+ virtual GCPolicyKind kind() const { return _gc_adaptive_size_policy; }
+
+ enum SizePolicyTrueValues {
+ decrease_old_gen_for_throughput_true = -7,
+ decrease_young_gen_for_througput_true = -6,
+
+ increase_old_gen_for_min_pauses_true = -5,
+ decrease_old_gen_for_min_pauses_true = -4,
+ decrease_young_gen_for_maj_pauses_true = -3,
+ increase_young_gen_for_min_pauses_true = -2,
+ increase_old_gen_for_maj_pauses_true = -1,
+
+ decrease_young_gen_for_min_pauses_true = 1,
+ decrease_old_gen_for_maj_pauses_true = 2,
+ increase_young_gen_for_maj_pauses_true = 3,
+
+ increase_old_gen_for_throughput_true = 4,
+ increase_young_gen_for_througput_true = 5,
+
+ decrease_young_gen_for_footprint_true = 6,
+ decrease_old_gen_for_footprint_true = 7,
+ decide_at_full_gc_true = 8
+ };
+
+ // Goal for the fraction of the total time during which application
+ // threads run
+ const double _throughput_goal;
+
+ // Last calculated sizes, in bytes, and aligned
+ size_t _eden_size; // calculated eden free space in bytes
+ size_t _promo_size; // calculated cms gen free space in bytes
+
+ size_t _survivor_size; // calculated survivor size in bytes
+
+ // This is a hint for the heap: we've detected that GC times
+ // are taking longer than GCTimeLimit allows.
+ bool _gc_overhead_limit_exceeded;
+ // Use for diagnostics only. If UseGCOverheadLimit is false,
+ // this variable is still set.
+ bool _print_gc_overhead_limit_would_be_exceeded;
+ // Count of consecutive GC that have exceeded the
+ // GC time limit criterion
+ uint _gc_overhead_limit_count;
+ // This flag signals that GCTimeLimit is being exceeded
+ // but may not have done so for the required number of consecutive
+ // collections
+
+ // Minor collection timers used to determine both
+ // pause and interval times for collections
+ static elapsedTimer _minor_timer;
+
+ // Major collection timers, used to determine both
+ // pause and interval times for collections
+ static elapsedTimer _major_timer;
+
+ // Time statistics
+ AdaptivePaddedAverage* _avg_minor_pause;
+ AdaptiveWeightedAverage* _avg_minor_interval;
+ AdaptiveWeightedAverage* _avg_minor_gc_cost;
+
+ AdaptiveWeightedAverage* _avg_major_interval;
+ AdaptiveWeightedAverage* _avg_major_gc_cost;
+
+ // Footprint statistics
+ AdaptiveWeightedAverage* _avg_young_live;
+ AdaptiveWeightedAverage* _avg_eden_live;
+ AdaptiveWeightedAverage* _avg_old_live;
+
+ // Statistics for survivor space calculation for young generation
+ AdaptivePaddedAverage* _avg_survived;
+
+ // Objects that have been directly allocated in the old generation
+ AdaptivePaddedNoZeroDevAverage* _avg_pretenured;
+
+ // Variable for estimating the major and minor pause times.
+ // These variables represent linear least-squares fits of
+ // the data.
+ // minor pause time vs. old gen size
+ LinearLeastSquareFit* _minor_pause_old_estimator;
+ // minor pause time vs. young gen size
+ LinearLeastSquareFit* _minor_pause_young_estimator;
+
+ // Variables for estimating the major and minor collection costs
+ // minor collection time vs. young gen size
+ LinearLeastSquareFit* _minor_collection_estimator;
+ // major collection time vs. cms gen size
+ LinearLeastSquareFit* _major_collection_estimator;
+
+ // These record the most recent collection times. They
+ // are available as an alternative to using the averages
+ // for making ergonomic decisions.
+ double _latest_minor_mutator_interval_seconds;
+
+ // Allowed difference between major and minor GC times, used
+ // for computing tenuring_threshold
+ const double _threshold_tolerance_percent;
+
+ const double _gc_pause_goal_sec; // Goal for maximum GC pause
+
+ // Flag indicating that the adaptive policy is ready to use
+ bool _young_gen_policy_is_ready;
+
+ // Decrease/increase the young generation for minor pause time
+ int _change_young_gen_for_min_pauses;
+
+ // Decrease/increase the old generation for major pause time
+ int _change_old_gen_for_maj_pauses;
+
+ // change old generation for throughput
+ int _change_old_gen_for_throughput;
+
+ // change young generation for throughput
+ int _change_young_gen_for_throughput;
+
+ // Flag indicating that the policy would
+ // increase the tenuring threshold because of the total major GC cost
+ // is greater than the total minor GC cost
+ bool _increment_tenuring_threshold_for_gc_cost;
+ // decrease the tenuring threshold because of the the total minor GC
+ // cost is greater than the total major GC cost
+ bool _decrement_tenuring_threshold_for_gc_cost;
+ // decrease due to survivor size limit
+ bool _decrement_tenuring_threshold_for_survivor_limit;
+
+ // decrease generation sizes for footprint
+ int _decrease_for_footprint;
+
+ // Set if the ergonomic decisions were made at a full GC.
+ int _decide_at_full_gc;
+
+ // Changing the generation sizing depends on the data that is
+ // gathered about the effects of changes on the pause times and
+ // throughput. These variable count the number of data points
+ // gathered. The policy may use these counters as a threshold
+ // for reliable data.
+ julong _young_gen_change_for_minor_throughput;
+ julong _old_gen_change_for_major_throughput;
+
+ static const uint GCWorkersPerJavaThread = 2;
+
+ // Accessors
+
+ double gc_pause_goal_sec() const { return _gc_pause_goal_sec; }
+ // The value returned is unitless: it's the proportion of time
+ // spent in a particular collection type.
+ // An interval time will be 0.0 if a collection type hasn't occurred yet.
+ // The 1.4.2 implementation put a floor on the values of major_gc_cost
+ // and minor_gc_cost. This was useful because of the way major_gc_cost
+ // and minor_gc_cost was used in calculating the sizes of the generations.
+ // Do not use a floor in this implementation because any finite value
+ // will put a limit on the throughput that can be achieved and any
+ // throughput goal above that limit will drive the generations sizes
+ // to extremes.
+ double major_gc_cost() const {
+ return MAX2(0.0F, _avg_major_gc_cost->average());
+ }
+
+ // The value returned is unitless: it's the proportion of time
+ // spent in a particular collection type.
+ // An interval time will be 0.0 if a collection type hasn't occurred yet.
+ // The 1.4.2 implementation put a floor on the values of major_gc_cost
+ // and minor_gc_cost. This was useful because of the way major_gc_cost
+ // and minor_gc_cost was used in calculating the sizes of the generations.
+ // Do not use a floor in this implementation because any finite value
+ // will put a limit on the throughput that can be achieved and any
+ // throughput goal above that limit will drive the generations sizes
+ // to extremes.
+
+ double minor_gc_cost() const {
+ return MAX2(0.0F, _avg_minor_gc_cost->average());
+ }
+
+ // Because we're dealing with averages, gc_cost() can be
+ // larger than 1.0 if just the sum of the minor cost the
+ // the major cost is used. Worse than that is the
+ // fact that the minor cost and the major cost each
+ // tend toward 1.0 in the extreme of high GC costs.
+ // Limit the value of gc_cost to 1.0 so that the mutator
+ // cost stays non-negative.
+ virtual double gc_cost() const {
+ double result = MIN2(1.0, minor_gc_cost() + major_gc_cost());
+ assert(result >= 0.0, "Both minor and major costs are non-negative");
+ return result;
+ }
+
+ // Elapsed time since the last major collection.
+ virtual double time_since_major_gc() const;
+
+ // Average interval between major collections to be used
+ // in calculating the decaying major GC cost. An overestimate
+ // of this time would be a conservative estimate because
+ // this time is used to decide if the major GC cost
+ // should be decayed (i.e., if the time since the last
+ // major GC is long compared to the time returned here,
+ // then the major GC cost will be decayed). See the
+ // implementations for the specifics.
+ virtual double major_gc_interval_average_for_decay() const {
+ return _avg_major_interval->average();
+ }
+
+ // Return the cost of the GC where the major GC cost
+ // has been decayed based on the time since the last
+ // major collection.
+ double decaying_gc_cost() const;
+
+ // Decay the major GC cost. Use this only for decisions on
+ // whether to adjust, not to determine by how much to adjust.
+ // This approximation is crude and may not be good enough for the
+ // latter.
+ double decaying_major_gc_cost() const;
+
+ // Return the mutator cost using the decayed
+ // GC cost.
+ double adjusted_mutator_cost() const {
+ double result = 1.0 - decaying_gc_cost();
+ assert(result >= 0.0, "adjusted mutator cost calculation is incorrect");
+ return result;
+ }
+
+ virtual double mutator_cost() const {
+ double result = 1.0 - gc_cost();
+ assert(result >= 0.0, "mutator cost calculation is incorrect");
+ return result;
+ }
+
+
+ bool young_gen_policy_is_ready() { return _young_gen_policy_is_ready; }
+
+ void update_minor_pause_young_estimator(double minor_pause_in_ms);
+ virtual void update_minor_pause_old_estimator(double minor_pause_in_ms) {
+ // This is not meaningful for all policies but needs to be present
+ // to use minor_collection_end() in its current form.
+ }
+
+ virtual size_t eden_increment(size_t cur_eden);
+ virtual size_t eden_increment(size_t cur_eden, uint percent_change);
+ virtual size_t eden_decrement(size_t cur_eden);
+ virtual size_t promo_increment(size_t cur_eden);
+ virtual size_t promo_increment(size_t cur_eden, uint percent_change);
+ virtual size_t promo_decrement(size_t cur_eden);
+
+ virtual void clear_generation_free_space_flags();
+
+ int change_old_gen_for_throughput() const {
+ return _change_old_gen_for_throughput;
+ }
+ void set_change_old_gen_for_throughput(int v) {
+ _change_old_gen_for_throughput = v;
+ }
+ int change_young_gen_for_throughput() const {
+ return _change_young_gen_for_throughput;
+ }
+ void set_change_young_gen_for_throughput(int v) {
+ _change_young_gen_for_throughput = v;
+ }
+
+ int change_old_gen_for_maj_pauses() const {
+ return _change_old_gen_for_maj_pauses;
+ }
+ void set_change_old_gen_for_maj_pauses(int v) {
+ _change_old_gen_for_maj_pauses = v;
+ }
+
+ bool decrement_tenuring_threshold_for_gc_cost() const {
+ return _decrement_tenuring_threshold_for_gc_cost;
+ }
+ void set_decrement_tenuring_threshold_for_gc_cost(bool v) {
+ _decrement_tenuring_threshold_for_gc_cost = v;
+ }
+ bool increment_tenuring_threshold_for_gc_cost() const {
+ return _increment_tenuring_threshold_for_gc_cost;
+ }
+ void set_increment_tenuring_threshold_for_gc_cost(bool v) {
+ _increment_tenuring_threshold_for_gc_cost = v;
+ }
+ bool decrement_tenuring_threshold_for_survivor_limit() const {
+ return _decrement_tenuring_threshold_for_survivor_limit;
+ }
+ void set_decrement_tenuring_threshold_for_survivor_limit(bool v) {
+ _decrement_tenuring_threshold_for_survivor_limit = v;
+ }
+ // Return true if the policy suggested a change.
+ bool tenuring_threshold_change() const;
+
+ static bool _debug_perturbation;
+
+ public:
+ 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);
+
+ // Return number default GC threads to use in the next GC.
+ static uint calc_default_active_workers(uintx total_workers,
+ const uintx min_workers,
+ uintx active_workers,
+ uintx application_workers);
+
+ // Return number of GC threads to use in the next GC.
+ // This is called sparingly so as not to change the
+ // number of GC workers gratuitously.
+ // For ParNew collections
+ // For PS scavenge and ParOld collections
+ // For G1 evacuation pauses (subject to update)
+ // Other collection phases inherit the number of
+ // GC workers from the calls above. For example,
+ // a CMS parallel remark uses the same number of GC
+ // workers as the most recent ParNew collection.
+ static uint calc_active_workers(uintx total_workers,
+ uintx active_workers,
+ uintx application_workers);
+
+ // Return number of GC threads to use in the next concurrent GC phase.
+ static uint calc_active_conc_workers(uintx total_workers,
+ uintx active_workers,
+ uintx application_workers);
+
+ bool is_gc_cms_adaptive_size_policy() {
+ return kind() == _gc_cms_adaptive_size_policy;
+ }
+ bool is_gc_ps_adaptive_size_policy() {
+ return kind() == _gc_ps_adaptive_size_policy;
+ }
+
+ AdaptivePaddedAverage* avg_minor_pause() const { return _avg_minor_pause; }
+ AdaptiveWeightedAverage* avg_minor_interval() const {
+ return _avg_minor_interval;
+ }
+ AdaptiveWeightedAverage* avg_minor_gc_cost() const {
+ return _avg_minor_gc_cost;
+ }
+
+ AdaptiveWeightedAverage* avg_major_gc_cost() const {
+ return _avg_major_gc_cost;
+ }
+
+ AdaptiveWeightedAverage* avg_young_live() const { return _avg_young_live; }
+ AdaptiveWeightedAverage* avg_eden_live() const { return _avg_eden_live; }
+ AdaptiveWeightedAverage* avg_old_live() const { return _avg_old_live; }
+
+ AdaptivePaddedAverage* avg_survived() const { return _avg_survived; }
+ AdaptivePaddedNoZeroDevAverage* avg_pretenured() { return _avg_pretenured; }
+
+ // Methods indicating events of interest to the adaptive size policy,
+ // called by GC algorithms. It is the responsibility of users of this
+ // policy to call these methods at the correct times!
+ virtual void minor_collection_begin();
+ virtual void minor_collection_end(GCCause::Cause gc_cause);
+ virtual LinearLeastSquareFit* minor_pause_old_estimator() const {
+ return _minor_pause_old_estimator;
+ }
+
+ LinearLeastSquareFit* minor_pause_young_estimator() {
+ return _minor_pause_young_estimator;
+ }
+ LinearLeastSquareFit* minor_collection_estimator() {
+ return _minor_collection_estimator;
+ }
+
+ LinearLeastSquareFit* major_collection_estimator() {
+ return _major_collection_estimator;
+ }
+
+ float minor_pause_young_slope() {
+ return _minor_pause_young_estimator->slope();
+ }
+
+ float minor_collection_slope() { return _minor_collection_estimator->slope();}
+ float major_collection_slope() { return _major_collection_estimator->slope();}
+
+ float minor_pause_old_slope() {
+ return _minor_pause_old_estimator->slope();
+ }
+
+ void set_eden_size(size_t new_size) {
+ _eden_size = new_size;
+ }
+ void set_survivor_size(size_t new_size) {
+ _survivor_size = new_size;
+ }
+
+ size_t calculated_eden_size_in_bytes() const {
+ return _eden_size;
+ }
+
+ size_t calculated_promo_size_in_bytes() const {
+ return _promo_size;
+ }
+
+ size_t calculated_survivor_size_in_bytes() const {
+ return _survivor_size;
+ }
+
+ // This is a hint for the heap: we've detected that gc times
+ // are taking longer than GCTimeLimit allows.
+ // Most heaps will choose to throw an OutOfMemoryError when
+ // this occurs but it is up to the heap to request this information
+ // of the policy
+ bool gc_overhead_limit_exceeded() {
+ return _gc_overhead_limit_exceeded;
+ }
+ void set_gc_overhead_limit_exceeded(bool v) {
+ _gc_overhead_limit_exceeded = v;
+ }
+
+ // Tests conditions indicate the GC overhead limit is being approached.
+ bool gc_overhead_limit_near() {
+ return gc_overhead_limit_count() >=
+ (AdaptiveSizePolicyGCTimeLimitThreshold - 1);
+ }
+ uint gc_overhead_limit_count() { return _gc_overhead_limit_count; }
+ void reset_gc_overhead_limit_count() { _gc_overhead_limit_count = 0; }
+ void inc_gc_overhead_limit_count() { _gc_overhead_limit_count++; }
+ // accessors for flags recording the decisions to resize the
+ // generations to meet the pause goal.
+
+ int change_young_gen_for_min_pauses() const {
+ return _change_young_gen_for_min_pauses;
+ }
+ void set_change_young_gen_for_min_pauses(int v) {
+ _change_young_gen_for_min_pauses = v;
+ }
+ void set_decrease_for_footprint(int v) { _decrease_for_footprint = v; }
+ int decrease_for_footprint() const { return _decrease_for_footprint; }
+ int decide_at_full_gc() { return _decide_at_full_gc; }
+ void set_decide_at_full_gc(int v) { _decide_at_full_gc = v; }
+
+ // Check the conditions for an out-of-memory due to excessive GC time.
+ // Set _gc_overhead_limit_exceeded if all the conditions have been met.
+ void 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);
+
+ // Printing support
+ virtual bool print_adaptive_size_policy_on(outputStream* st) const;
+ bool print_adaptive_size_policy_on(outputStream* st,
+ uint tenuring_threshold) const;
+};
+
+// Class that can be used to print information about the
+// adaptive size policy at intervals specified by
+// AdaptiveSizePolicyOutputInterval. Only print information
+// if an adaptive size policy is in use.
+class AdaptiveSizePolicyOutput : StackObj {
+ AdaptiveSizePolicy* _size_policy;
+ bool _do_print;
+ bool print_test(uint count) {
+ // A count of zero is a special value that indicates that the
+ // interval test should be ignored. An interval is of zero is
+ // a special value that indicates that the interval test should
+ // always fail (never do the print based on the interval test).
+ return PrintGCDetails &&
+ UseAdaptiveSizePolicy &&
+ UseParallelGC &&
+ (AdaptiveSizePolicyOutputInterval > 0) &&
+ ((count == 0) ||
+ ((count % AdaptiveSizePolicyOutputInterval) == 0));
+ }
+ public:
+ // The special value of a zero count can be used to ignore
+ // the count test.
+ AdaptiveSizePolicyOutput(uint count) {
+ if (UseAdaptiveSizePolicy && (AdaptiveSizePolicyOutputInterval > 0)) {
+ CollectedHeap* heap = Universe::heap();
+ _size_policy = heap->size_policy();
+ _do_print = print_test(count);
+ } else {
+ _size_policy = NULL;
+ _do_print = false;
+ }
+ }
+ AdaptiveSizePolicyOutput(AdaptiveSizePolicy* size_policy,
+ uint count) :
+ _size_policy(size_policy) {
+ if (UseAdaptiveSizePolicy && (AdaptiveSizePolicyOutputInterval > 0)) {
+ _do_print = print_test(count);
+ } else {
+ _do_print = false;
+ }
+ }
+ ~AdaptiveSizePolicyOutput() {
+ if (_do_print) {
+ assert(UseAdaptiveSizePolicy, "Should not be in use");
+ _size_policy->print_adaptive_size_policy_on(gclog_or_tty);
+ }
+ }
+};
+
+#endif // SHARE_VM_GC_SHARED_ADAPTIVESIZEPOLICY_HPP