| /* |
| * 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. |
| * |
| */ |
| |
| #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 "logging/log.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); |
| |
| static bool should_update_promo_stats(GCCause::Cause cause) { |
| return ((GCCause::is_user_requested_gc(cause) && |
| UseAdaptiveSizePolicyWithSystemGC) || |
| GCCause::is_tenured_allocation_failure_gc(cause)); |
| } |
| |
| static bool should_update_eden_stats(GCCause::Cause cause) { |
| return ((GCCause::is_user_requested_gc(cause) && |
| UseAdaptiveSizePolicyWithSystemGC) || |
| GCCause::is_allocation_failure_gc(cause)); |
| } |
| |
| // Printing support |
| virtual bool print() const; |
| void print_tenuring_threshold(uint new_tenuring_threshold) const; |
| }; |
| |
| #endif // SHARE_VM_GC_SHARED_ADAPTIVESIZEPOLICY_HPP |