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view src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp @ 1294:7de45b5044c3
6932270: Allow Java's ELF symtab reader to use separate debuginfo files
Reviewed-by: never
Contributed-by: Andrew Haley <aph@redhat.com>
author | never |
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date | Tue, 09 Mar 2010 11:02:39 -0800 |
parents | a61af66fc99e |
children | 0bfd3fb24150 |
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/* * Copyright 2002-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ // 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 optimial 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 _intra_generation_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 threshhold // 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; } // Change the young generation size to achieve a minor GC pause time goal void adjust_for_minor_pause_time(bool is_full_gc, size_t* desired_promo_size_ptr, 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_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_for_throughput(bool is_full_gc, size_t* desired_promo_size_ptr, 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); // Decay the supplemental growth additive. void decay_supplemental_growth(bool is_full_gc); // 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 intra_generation_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 size_t calculated_old_free_size_in_bytes() const { return (size_t)(_promo_size + avg_promoted()->padded_average()); } 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 optimial free space sizes for both the old and young // 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_generation_free_space(size_t young_live, size_t eden_live, size_t old_live, size_t perm_live, size_t cur_eden, // current eden in bytes size_t max_old_gen_size, size_t max_eden_size, bool is_full_gc, GCCause::Cause gc_cause); // Calculates new survivor space size; returns a new tenuring threshold // value. Stores new survivor size in _survivor_size. int compute_survivor_space_size_and_threshold(bool is_survivor_overflow, int 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 = _intra_generation_alignment; return sz > alignment ? align_size_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_adaptive_size_policy_on(outputStream* st) const; };