| /* |
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| * accompanied this code). |
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| |
| #ifndef SHARE_VM_GC_PARALLEL_PSADAPTIVESIZEPOLICY_HPP |
| #define SHARE_VM_GC_PARALLEL_PSADAPTIVESIZEPOLICY_HPP |
| |
| #include "gc/shared/adaptiveSizePolicy.hpp" |
| #include "gc/shared/gcCause.hpp" |
| #include "gc/shared/gcStats.hpp" |
| #include "gc/shared/gcUtil.hpp" |
| #include "utilities/align.hpp" |
| |
| // This class keeps statistical information and computes the |
| // optimal free space for both the young and old generation |
| // based on current application characteristics (based on gc cost |
| // and application footprint). |
| // |
| // It also computes an optimal tenuring threshold between the young |
| // and old generations, so as to equalize the cost of collections |
| // of those generations, as well as optimal survivor space sizes |
| // for the young generation. |
| // |
| // While this class is specifically intended for a generational system |
| // consisting of a young gen (containing an Eden and two semi-spaces) |
| // and a tenured gen, as well as a perm gen for reflective data, it |
| // makes NO references to specific generations. |
| // |
| // 05/02/2003 Update |
| // The 1.5 policy makes use of data gathered for the costs of GC on |
| // specific generations. That data does reference specific |
| // generation. Also diagnostics specific to generations have |
| // been added. |
| |
| // Forward decls |
| class elapsedTimer; |
| |
| class PSAdaptiveSizePolicy : public AdaptiveSizePolicy { |
| friend class PSGCAdaptivePolicyCounters; |
| private: |
| // These values are used to record decisions made during the |
| // policy. For example, if the young generation was decreased |
| // to decrease the GC cost of minor collections the value |
| // decrease_young_gen_for_throughput_true is used. |
| |
| // Last calculated sizes, in bytes, and aligned |
| // NEEDS_CLEANUP should use sizes.hpp, but it works in ints, not size_t's |
| |
| // Time statistics |
| AdaptivePaddedAverage* _avg_major_pause; |
| |
| // Footprint statistics |
| AdaptiveWeightedAverage* _avg_base_footprint; |
| |
| // Statistical data gathered for GC |
| GCStats _gc_stats; |
| |
| size_t _survivor_size_limit; // Limit in bytes of survivor size |
| const double _collection_cost_margin_fraction; |
| |
| // Variable for estimating the major and minor pause times. |
| // These variables represent linear least-squares fits of |
| // the data. |
| // major pause time vs. old gen size |
| LinearLeastSquareFit* _major_pause_old_estimator; |
| // major pause time vs. young gen size |
| LinearLeastSquareFit* _major_pause_young_estimator; |
| |
| |
| // These record the most recent collection times. They |
| // are available as an alternative to using the averages |
| // for making ergonomic decisions. |
| double _latest_major_mutator_interval_seconds; |
| |
| const size_t _space_alignment; // alignment for eden, survivors |
| |
| const double _gc_minor_pause_goal_sec; // goal for maximum minor gc pause |
| |
| // The amount of live data in the heap at the last full GC, used |
| // as a baseline to help us determine when we need to perform the |
| // next full GC. |
| size_t _live_at_last_full_gc; |
| |
| // decrease/increase the old generation for minor pause time |
| int _change_old_gen_for_min_pauses; |
| |
| // increase/decrease the young generation for major pause time |
| int _change_young_gen_for_maj_pauses; |
| |
| |
| // Flag indicating that the adaptive policy is ready to use |
| bool _old_gen_policy_is_ready; |
| |
| // 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_major_pause_count; |
| |
| // To facilitate faster growth at start up, supplement the normal |
| // growth percentage for the young gen eden and the |
| // old gen space for promotion with these value which decay |
| // with increasing collections. |
| uint _young_gen_size_increment_supplement; |
| uint _old_gen_size_increment_supplement; |
| |
| // The number of bytes absorbed from eden into the old gen by moving the |
| // boundary over live data. |
| size_t _bytes_absorbed_from_eden; |
| |
| private: |
| |
| // Accessors |
| AdaptivePaddedAverage* avg_major_pause() const { return _avg_major_pause; } |
| double gc_minor_pause_goal_sec() const { return _gc_minor_pause_goal_sec; } |
| |
| void adjust_eden_for_minor_pause_time(bool is_full_gc, |
| size_t* desired_eden_size_ptr); |
| // Change the generation sizes to achieve a GC pause time goal |
| // Returned sizes are not necessarily aligned. |
| void adjust_promo_for_pause_time(bool is_full_gc, |
| size_t* desired_promo_size_ptr, |
| size_t* desired_eden_size_ptr); |
| void adjust_eden_for_pause_time(bool is_full_gc, |
| size_t* desired_promo_size_ptr, |
| size_t* desired_eden_size_ptr); |
| // Change the generation sizes to achieve an application throughput goal |
| // Returned sizes are not necessarily aligned. |
| void adjust_promo_for_throughput(bool is_full_gc, |
| size_t* desired_promo_size_ptr); |
| void adjust_eden_for_throughput(bool is_full_gc, |
| size_t* desired_eden_size_ptr); |
| // Change the generation sizes to achieve minimum footprint |
| // Returned sizes are not aligned. |
| size_t adjust_promo_for_footprint(size_t desired_promo_size, |
| size_t desired_total); |
| size_t adjust_eden_for_footprint(size_t desired_promo_size, |
| size_t desired_total); |
| |
| // Size in bytes for an increment or decrement of eden. |
| virtual size_t eden_increment(size_t cur_eden, uint percent_change); |
| virtual size_t eden_decrement(size_t cur_eden); |
| size_t eden_decrement_aligned_down(size_t cur_eden); |
| size_t eden_increment_with_supplement_aligned_up(size_t cur_eden); |
| |
| // Size in bytes for an increment or decrement of the promotion area |
| virtual size_t promo_increment(size_t cur_promo, uint percent_change); |
| virtual size_t promo_decrement(size_t cur_promo); |
| size_t promo_decrement_aligned_down(size_t cur_promo); |
| size_t promo_increment_with_supplement_aligned_up(size_t cur_promo); |
| |
| // Returns a change that has been scaled down. Result |
| // is not aligned. (If useful, move to some shared |
| // location.) |
| size_t scale_down(size_t change, double part, double total); |
| |
| protected: |
| // Time accessors |
| |
| // Footprint accessors |
| size_t live_space() const { |
| return (size_t)(avg_base_footprint()->average() + |
| avg_young_live()->average() + |
| avg_old_live()->average()); |
| } |
| size_t free_space() const { |
| return _eden_size + _promo_size; |
| } |
| |
| void set_promo_size(size_t new_size) { |
| _promo_size = new_size; |
| } |
| void set_survivor_size(size_t new_size) { |
| _survivor_size = new_size; |
| } |
| |
| // Update estimators |
| void update_minor_pause_old_estimator(double minor_pause_in_ms); |
| |
| virtual GCPolicyKind kind() const { return _gc_ps_adaptive_size_policy; } |
| |
| public: |
| // Use by ASPSYoungGen and ASPSOldGen to limit boundary moving. |
| size_t eden_increment_aligned_up(size_t cur_eden); |
| size_t eden_increment_aligned_down(size_t cur_eden); |
| size_t promo_increment_aligned_up(size_t cur_promo); |
| size_t promo_increment_aligned_down(size_t cur_promo); |
| |
| virtual size_t eden_increment(size_t cur_eden); |
| virtual size_t promo_increment(size_t cur_promo); |
| |
| // Accessors for use by performance counters |
| AdaptivePaddedNoZeroDevAverage* avg_promoted() const { |
| return _gc_stats.avg_promoted(); |
| } |
| AdaptiveWeightedAverage* avg_base_footprint() const { |
| return _avg_base_footprint; |
| } |
| |
| // Input arguments are initial free space sizes for young and old |
| // generations, the initial survivor space size, the |
| // alignment values and the pause & throughput goals. |
| // |
| // NEEDS_CLEANUP this is a singleton object |
| PSAdaptiveSizePolicy(size_t init_eden_size, |
| size_t init_promo_size, |
| size_t init_survivor_size, |
| size_t space_alignment, |
| double gc_pause_goal_sec, |
| double gc_minor_pause_goal_sec, |
| uint gc_time_ratio); |
| |
| // 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! |
| void major_collection_begin(); |
| void major_collection_end(size_t amount_live, GCCause::Cause gc_cause); |
| |
| void tenured_allocation(size_t size) { |
| _avg_pretenured->sample(size); |
| } |
| |
| // Accessors |
| // NEEDS_CLEANUP should use sizes.hpp |
| |
| static size_t calculate_free_based_on_live(size_t live, uintx ratio_as_percentage); |
| |
| size_t calculated_old_free_size_in_bytes() const; |
| |
| size_t average_old_live_in_bytes() const { |
| return (size_t) avg_old_live()->average(); |
| } |
| |
| size_t average_promoted_in_bytes() const { |
| return (size_t)avg_promoted()->average(); |
| } |
| |
| size_t padded_average_promoted_in_bytes() const { |
| return (size_t)avg_promoted()->padded_average(); |
| } |
| |
| int change_young_gen_for_maj_pauses() { |
| return _change_young_gen_for_maj_pauses; |
| } |
| void set_change_young_gen_for_maj_pauses(int v) { |
| _change_young_gen_for_maj_pauses = v; |
| } |
| |
| int change_old_gen_for_min_pauses() { |
| return _change_old_gen_for_min_pauses; |
| } |
| void set_change_old_gen_for_min_pauses(int v) { |
| _change_old_gen_for_min_pauses = v; |
| } |
| |
| // Return true if the old generation size was changed |
| // to try to reach a pause time goal. |
| bool old_gen_changed_for_pauses() { |
| bool result = _change_old_gen_for_maj_pauses != 0 || |
| _change_old_gen_for_min_pauses != 0; |
| return result; |
| } |
| |
| // Return true if the young generation size was changed |
| // to try to reach a pause time goal. |
| bool young_gen_changed_for_pauses() { |
| bool result = _change_young_gen_for_min_pauses != 0 || |
| _change_young_gen_for_maj_pauses != 0; |
| return result; |
| } |
| // end flags for pause goal |
| |
| // Return true if the old generation size was changed |
| // to try to reach a throughput goal. |
| bool old_gen_changed_for_throughput() { |
| bool result = _change_old_gen_for_throughput != 0; |
| return result; |
| } |
| |
| // Return true if the young generation size was changed |
| // to try to reach a throughput goal. |
| bool young_gen_changed_for_throughput() { |
| bool result = _change_young_gen_for_throughput != 0; |
| return result; |
| } |
| |
| int decrease_for_footprint() { return _decrease_for_footprint; } |
| |
| |
| // Accessors for estimators. The slope of the linear fit is |
| // currently all that is used for making decisions. |
| |
| LinearLeastSquareFit* major_pause_old_estimator() { |
| return _major_pause_old_estimator; |
| } |
| |
| LinearLeastSquareFit* major_pause_young_estimator() { |
| return _major_pause_young_estimator; |
| } |
| |
| |
| virtual void clear_generation_free_space_flags(); |
| |
| float major_pause_old_slope() { return _major_pause_old_estimator->slope(); } |
| float major_pause_young_slope() { |
| return _major_pause_young_estimator->slope(); |
| } |
| float major_collection_slope() { return _major_collection_estimator->slope();} |
| |
| bool old_gen_policy_is_ready() { return _old_gen_policy_is_ready; } |
| |
| // Given the amount of live data in the heap, should we |
| // perform a Full GC? |
| bool should_full_GC(size_t live_in_old_gen); |
| |
| // Calculates optimal (free) space sizes for both the young and old |
| // generations. Stores results in _eden_size and _promo_size. |
| // Takes current used space in all generations as input, as well |
| // as an indication if a full gc has just been performed, for use |
| // in deciding if an OOM error should be thrown. |
| void compute_generations_free_space(size_t young_live, |
| size_t eden_live, |
| size_t old_live, |
| size_t cur_eden, // current eden in bytes |
| size_t max_old_gen_size, |
| size_t max_eden_size, |
| bool is_full_gc); |
| |
| void compute_eden_space_size(size_t young_live, |
| size_t eden_live, |
| size_t cur_eden, // current eden in bytes |
| size_t max_eden_size, |
| bool is_full_gc); |
| |
| void compute_old_gen_free_space(size_t old_live, |
| size_t cur_eden, // current eden in bytes |
| size_t max_old_gen_size, |
| bool is_full_gc); |
| |
| // Calculates new survivor space size; returns a new tenuring threshold |
| // value. Stores new survivor size in _survivor_size. |
| uint compute_survivor_space_size_and_threshold(bool is_survivor_overflow, |
| uint tenuring_threshold, |
| size_t survivor_limit); |
| |
| // Return the maximum size of a survivor space if the young generation were of |
| // size gen_size. |
| size_t max_survivor_size(size_t gen_size) { |
| // Never allow the target survivor size to grow more than MinSurvivorRatio |
| // of the young generation size. We cannot grow into a two semi-space |
| // system, with Eden zero sized. Even if the survivor space grows, from() |
| // might grow by moving the bottom boundary "down" -- so from space will |
| // remain almost full anyway (top() will be near end(), but there will be a |
| // large filler object at the bottom). |
| const size_t sz = gen_size / MinSurvivorRatio; |
| const size_t alignment = _space_alignment; |
| return sz > alignment ? align_down(sz, alignment) : alignment; |
| } |
| |
| size_t live_at_last_full_gc() { |
| return _live_at_last_full_gc; |
| } |
| |
| size_t bytes_absorbed_from_eden() const { return _bytes_absorbed_from_eden; } |
| void reset_bytes_absorbed_from_eden() { _bytes_absorbed_from_eden = 0; } |
| |
| void set_bytes_absorbed_from_eden(size_t val) { |
| _bytes_absorbed_from_eden = val; |
| } |
| |
| // Update averages that are always used (even |
| // if adaptive sizing is turned off). |
| void update_averages(bool is_survivor_overflow, |
| size_t survived, |
| size_t promoted); |
| |
| // Printing support |
| virtual bool print() const; |
| |
| // Decay the supplemental growth additive. |
| void decay_supplemental_growth(bool is_full_gc); |
| }; |
| |
| #endif // SHARE_VM_GC_PARALLEL_PSADAPTIVESIZEPOLICY_HPP |