Mercurial > hg > truffle
view src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp @ 605:98cb887364d3
6810672: Comment typos
Summary: I have collected some typos I have found while looking at the code.
Reviewed-by: kvn, never
author | twisti |
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date | Fri, 27 Feb 2009 13:27:09 -0800 |
parents | fe3d7c11b4b7 |
children | 0fbdb4381b99 3698e8f47799 |
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/* * Copyright 2001-2007 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. * */ // A G1CollectorPolicy makes policy decisions that determine the // characteristics of the collector. Examples include: // * choice of collection set. // * when to collect. class HeapRegion; class CollectionSetChooser; // Yes, this is a bit unpleasant... but it saves replicating the same thing // over and over again and introducing subtle problems through small typos and // cutting and pasting mistakes. The macros below introduces a number // sequnce into the following two classes and the methods that access it. #define define_num_seq(name) \ private: \ NumberSeq _all_##name##_times_ms; \ public: \ void record_##name##_time_ms(double ms) { \ _all_##name##_times_ms.add(ms); \ } \ NumberSeq* get_##name##_seq() { \ return &_all_##name##_times_ms; \ } class MainBodySummary; class PopPreambleSummary; class PauseSummary: public CHeapObj { define_num_seq(total) define_num_seq(other) public: virtual MainBodySummary* main_body_summary() { return NULL; } virtual PopPreambleSummary* pop_preamble_summary() { return NULL; } }; class MainBodySummary: public CHeapObj { define_num_seq(satb_drain) // optional define_num_seq(parallel) // parallel only define_num_seq(ext_root_scan) define_num_seq(mark_stack_scan) define_num_seq(scan_only) define_num_seq(update_rs) define_num_seq(scan_rs) define_num_seq(scan_new_refs) // Only for temp use; added to // in parallel case. define_num_seq(obj_copy) define_num_seq(termination) // parallel only define_num_seq(parallel_other) // parallel only define_num_seq(mark_closure) define_num_seq(clear_ct) // parallel only }; class PopPreambleSummary: public CHeapObj { define_num_seq(pop_preamble) define_num_seq(pop_update_rs) define_num_seq(pop_scan_rs) define_num_seq(pop_closure_app) define_num_seq(pop_evacuation) define_num_seq(pop_other) }; class NonPopSummary: public PauseSummary, public MainBodySummary { public: virtual MainBodySummary* main_body_summary() { return this; } }; class PopSummary: public PauseSummary, public MainBodySummary, public PopPreambleSummary { public: virtual MainBodySummary* main_body_summary() { return this; } virtual PopPreambleSummary* pop_preamble_summary() { return this; } }; class NonPopAbandonedSummary: public PauseSummary { }; class PopAbandonedSummary: public PauseSummary, public PopPreambleSummary { public: virtual PopPreambleSummary* pop_preamble_summary() { return this; } }; class G1CollectorPolicy: public CollectorPolicy { protected: // The number of pauses during the execution. long _n_pauses; // either equal to the number of parallel threads, if ParallelGCThreads // has been set, or 1 otherwise int _parallel_gc_threads; enum SomePrivateConstants { NumPrevPausesForHeuristics = 10, NumPrevGCsForHeuristics = 10, NumAPIs = HeapRegion::MaxAge }; G1MMUTracker* _mmu_tracker; void initialize_flags(); void initialize_all() { initialize_flags(); initialize_size_info(); initialize_perm_generation(PermGen::MarkSweepCompact); } virtual size_t default_init_heap_size() { // Pick some reasonable default. return 8*M; } double _cur_collection_start_sec; size_t _cur_collection_pause_used_at_start_bytes; size_t _cur_collection_pause_used_regions_at_start; size_t _prev_collection_pause_used_at_end_bytes; double _cur_collection_par_time_ms; double _cur_satb_drain_time_ms; double _cur_clear_ct_time_ms; bool _satb_drain_time_set; double _cur_popular_preamble_start_ms; double _cur_popular_preamble_time_ms; double _cur_popular_compute_rc_time_ms; double _cur_popular_evac_time_ms; double _cur_CH_strong_roots_end_sec; double _cur_CH_strong_roots_dur_ms; double _cur_G1_strong_roots_end_sec; double _cur_G1_strong_roots_dur_ms; // Statistics for recent GC pauses. See below for how indexed. TruncatedSeq* _recent_CH_strong_roots_times_ms; TruncatedSeq* _recent_G1_strong_roots_times_ms; TruncatedSeq* _recent_evac_times_ms; // These exclude marking times. TruncatedSeq* _recent_pause_times_ms; TruncatedSeq* _recent_gc_times_ms; TruncatedSeq* _recent_CS_bytes_used_before; TruncatedSeq* _recent_CS_bytes_surviving; TruncatedSeq* _recent_rs_sizes; TruncatedSeq* _concurrent_mark_init_times_ms; TruncatedSeq* _concurrent_mark_remark_times_ms; TruncatedSeq* _concurrent_mark_cleanup_times_ms; NonPopSummary* _non_pop_summary; PopSummary* _pop_summary; NonPopAbandonedSummary* _non_pop_abandoned_summary; PopAbandonedSummary* _pop_abandoned_summary; NumberSeq* _all_pause_times_ms; NumberSeq* _all_full_gc_times_ms; double _stop_world_start; NumberSeq* _all_stop_world_times_ms; NumberSeq* _all_yield_times_ms; size_t _region_num_young; size_t _region_num_tenured; size_t _prev_region_num_young; size_t _prev_region_num_tenured; NumberSeq* _all_mod_union_times_ms; int _aux_num; NumberSeq* _all_aux_times_ms; double* _cur_aux_start_times_ms; double* _cur_aux_times_ms; bool* _cur_aux_times_set; double* _par_last_ext_root_scan_times_ms; double* _par_last_mark_stack_scan_times_ms; double* _par_last_scan_only_times_ms; double* _par_last_scan_only_regions_scanned; double* _par_last_update_rs_start_times_ms; double* _par_last_update_rs_times_ms; double* _par_last_update_rs_processed_buffers; double* _par_last_scan_rs_start_times_ms; double* _par_last_scan_rs_times_ms; double* _par_last_scan_new_refs_times_ms; double* _par_last_obj_copy_times_ms; double* _par_last_termination_times_ms; // there are two pases during popular pauses, so we need to store // somewhere the results of the first pass double* _pop_par_last_update_rs_start_times_ms; double* _pop_par_last_update_rs_times_ms; double* _pop_par_last_update_rs_processed_buffers; double* _pop_par_last_scan_rs_start_times_ms; double* _pop_par_last_scan_rs_times_ms; double* _pop_par_last_closure_app_times_ms; double _pop_compute_rc_start; double _pop_evac_start; // indicates that we are in young GC mode bool _in_young_gc_mode; // indicates whether we are in full young or partially young GC mode bool _full_young_gcs; // if true, then it tries to dynamically adjust the length of the // young list bool _adaptive_young_list_length; size_t _young_list_min_length; size_t _young_list_target_length; size_t _young_list_so_prefix_length; size_t _young_list_fixed_length; size_t _young_cset_length; bool _last_young_gc_full; double _target_pause_time_ms; unsigned _full_young_pause_num; unsigned _partial_young_pause_num; bool _during_marking; bool _in_marking_window; bool _in_marking_window_im; SurvRateGroup* _short_lived_surv_rate_group; SurvRateGroup* _survivor_surv_rate_group; // add here any more surv rate groups bool during_marking() { return _during_marking; } // <NEW PREDICTION> private: enum PredictionConstants { TruncatedSeqLength = 10 }; TruncatedSeq* _alloc_rate_ms_seq; double _prev_collection_pause_end_ms; TruncatedSeq* _pending_card_diff_seq; TruncatedSeq* _rs_length_diff_seq; TruncatedSeq* _cost_per_card_ms_seq; TruncatedSeq* _cost_per_scan_only_region_ms_seq; TruncatedSeq* _fully_young_cards_per_entry_ratio_seq; TruncatedSeq* _partially_young_cards_per_entry_ratio_seq; TruncatedSeq* _cost_per_entry_ms_seq; TruncatedSeq* _partially_young_cost_per_entry_ms_seq; TruncatedSeq* _cost_per_byte_ms_seq; TruncatedSeq* _constant_other_time_ms_seq; TruncatedSeq* _young_other_cost_per_region_ms_seq; TruncatedSeq* _non_young_other_cost_per_region_ms_seq; TruncatedSeq* _pending_cards_seq; TruncatedSeq* _scanned_cards_seq; TruncatedSeq* _rs_lengths_seq; TruncatedSeq* _cost_per_byte_ms_during_cm_seq; TruncatedSeq* _cost_per_scan_only_region_ms_during_cm_seq; TruncatedSeq* _young_gc_eff_seq; TruncatedSeq* _max_conc_overhead_seq; size_t _recorded_young_regions; size_t _recorded_scan_only_regions; size_t _recorded_non_young_regions; size_t _recorded_region_num; size_t _free_regions_at_end_of_collection; size_t _scan_only_regions_at_end_of_collection; size_t _recorded_rs_lengths; size_t _max_rs_lengths; size_t _recorded_marked_bytes; size_t _recorded_young_bytes; size_t _predicted_pending_cards; size_t _predicted_cards_scanned; size_t _predicted_rs_lengths; size_t _predicted_bytes_to_copy; double _predicted_survival_ratio; double _predicted_rs_update_time_ms; double _predicted_rs_scan_time_ms; double _predicted_scan_only_scan_time_ms; double _predicted_object_copy_time_ms; double _predicted_constant_other_time_ms; double _predicted_young_other_time_ms; double _predicted_non_young_other_time_ms; double _predicted_pause_time_ms; double _vtime_diff_ms; double _recorded_young_free_cset_time_ms; double _recorded_non_young_free_cset_time_ms; double _sigma; double _expensive_region_limit_ms; size_t _rs_lengths_prediction; size_t _known_garbage_bytes; double _known_garbage_ratio; double sigma() { return _sigma; } // A function that prevents us putting too much stock in small sample // sets. Returns a number between 2.0 and 1.0, depending on the number // of samples. 5 or more samples yields one; fewer scales linearly from // 2.0 at 1 sample to 1.0 at 5. double confidence_factor(int samples) { if (samples > 4) return 1.0; else return 1.0 + sigma() * ((double)(5 - samples))/2.0; } double get_new_neg_prediction(TruncatedSeq* seq) { return seq->davg() - sigma() * seq->dsd(); } #ifndef PRODUCT bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group); #endif // PRODUCT protected: double _pause_time_target_ms; double _recorded_young_cset_choice_time_ms; double _recorded_non_young_cset_choice_time_ms; bool _within_target; size_t _pending_cards; size_t _max_pending_cards; public: void set_region_short_lived(HeapRegion* hr) { hr->install_surv_rate_group(_short_lived_surv_rate_group); } void set_region_survivors(HeapRegion* hr) { hr->install_surv_rate_group(_survivor_surv_rate_group); } #ifndef PRODUCT bool verify_young_ages(); #endif // PRODUCT void tag_scan_only(size_t short_lived_scan_only_length); double get_new_prediction(TruncatedSeq* seq) { return MAX2(seq->davg() + sigma() * seq->dsd(), seq->davg() * confidence_factor(seq->num())); } size_t young_cset_length() { return _young_cset_length; } void record_max_rs_lengths(size_t rs_lengths) { _max_rs_lengths = rs_lengths; } size_t predict_pending_card_diff() { double prediction = get_new_neg_prediction(_pending_card_diff_seq); if (prediction < 0.00001) return 0; else return (size_t) prediction; } size_t predict_pending_cards() { size_t max_pending_card_num = _g1->max_pending_card_num(); size_t diff = predict_pending_card_diff(); size_t prediction; if (diff > max_pending_card_num) prediction = max_pending_card_num; else prediction = max_pending_card_num - diff; return prediction; } size_t predict_rs_length_diff() { return (size_t) get_new_prediction(_rs_length_diff_seq); } double predict_alloc_rate_ms() { return get_new_prediction(_alloc_rate_ms_seq); } double predict_cost_per_card_ms() { return get_new_prediction(_cost_per_card_ms_seq); } double predict_rs_update_time_ms(size_t pending_cards) { return (double) pending_cards * predict_cost_per_card_ms(); } double predict_fully_young_cards_per_entry_ratio() { return get_new_prediction(_fully_young_cards_per_entry_ratio_seq); } double predict_partially_young_cards_per_entry_ratio() { if (_partially_young_cards_per_entry_ratio_seq->num() < 2) return predict_fully_young_cards_per_entry_ratio(); else return get_new_prediction(_partially_young_cards_per_entry_ratio_seq); } size_t predict_young_card_num(size_t rs_length) { return (size_t) ((double) rs_length * predict_fully_young_cards_per_entry_ratio()); } size_t predict_non_young_card_num(size_t rs_length) { return (size_t) ((double) rs_length * predict_partially_young_cards_per_entry_ratio()); } double predict_rs_scan_time_ms(size_t card_num) { if (full_young_gcs()) return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq); else return predict_partially_young_rs_scan_time_ms(card_num); } double predict_partially_young_rs_scan_time_ms(size_t card_num) { if (_partially_young_cost_per_entry_ms_seq->num() < 3) return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq); else return (double) card_num * get_new_prediction(_partially_young_cost_per_entry_ms_seq); } double predict_scan_only_time_ms_during_cm(size_t scan_only_region_num) { if (_cost_per_scan_only_region_ms_during_cm_seq->num() < 3) return 1.5 * (double) scan_only_region_num * get_new_prediction(_cost_per_scan_only_region_ms_seq); else return (double) scan_only_region_num * get_new_prediction(_cost_per_scan_only_region_ms_during_cm_seq); } double predict_scan_only_time_ms(size_t scan_only_region_num) { if (_in_marking_window_im) return predict_scan_only_time_ms_during_cm(scan_only_region_num); else return (double) scan_only_region_num * get_new_prediction(_cost_per_scan_only_region_ms_seq); } double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) { if (_cost_per_byte_ms_during_cm_seq->num() < 3) return 1.1 * (double) bytes_to_copy * get_new_prediction(_cost_per_byte_ms_seq); else return (double) bytes_to_copy * get_new_prediction(_cost_per_byte_ms_during_cm_seq); } double predict_object_copy_time_ms(size_t bytes_to_copy) { if (_in_marking_window && !_in_marking_window_im) return predict_object_copy_time_ms_during_cm(bytes_to_copy); else return (double) bytes_to_copy * get_new_prediction(_cost_per_byte_ms_seq); } double predict_constant_other_time_ms() { return get_new_prediction(_constant_other_time_ms_seq); } double predict_young_other_time_ms(size_t young_num) { return (double) young_num * get_new_prediction(_young_other_cost_per_region_ms_seq); } double predict_non_young_other_time_ms(size_t non_young_num) { return (double) non_young_num * get_new_prediction(_non_young_other_cost_per_region_ms_seq); } void check_if_region_is_too_expensive(double predicted_time_ms); double predict_young_collection_elapsed_time_ms(size_t adjustment); double predict_base_elapsed_time_ms(size_t pending_cards); double predict_base_elapsed_time_ms(size_t pending_cards, size_t scanned_cards); size_t predict_bytes_to_copy(HeapRegion* hr); double predict_region_elapsed_time_ms(HeapRegion* hr, bool young); // for use by: calculate_optimal_so_length(length) void predict_gc_eff(size_t young_region_num, size_t so_length, double base_time_ms, double *gc_eff, double *pause_time_ms); // for use by: calculate_young_list_target_config(rs_length) bool predict_gc_eff(size_t young_region_num, size_t so_length, double base_time_with_so_ms, size_t init_free_regions, double target_pause_time_ms, double* gc_eff); void start_recording_regions(); void record_cset_region(HeapRegion* hr, bool young); void record_scan_only_regions(size_t scan_only_length); void end_recording_regions(); void record_vtime_diff_ms(double vtime_diff_ms) { _vtime_diff_ms = vtime_diff_ms; } void record_young_free_cset_time_ms(double time_ms) { _recorded_young_free_cset_time_ms = time_ms; } void record_non_young_free_cset_time_ms(double time_ms) { _recorded_non_young_free_cset_time_ms = time_ms; } double predict_young_gc_eff() { return get_new_neg_prediction(_young_gc_eff_seq); } double predict_survivor_regions_evac_time(); // </NEW PREDICTION> public: void cset_regions_freed() { bool propagate = _last_young_gc_full && !_in_marking_window; _short_lived_surv_rate_group->all_surviving_words_recorded(propagate); _survivor_surv_rate_group->all_surviving_words_recorded(propagate); // also call it on any more surv rate groups } void set_known_garbage_bytes(size_t known_garbage_bytes) { _known_garbage_bytes = known_garbage_bytes; size_t heap_bytes = _g1->capacity(); _known_garbage_ratio = (double) _known_garbage_bytes / (double) heap_bytes; } void decrease_known_garbage_bytes(size_t known_garbage_bytes) { guarantee( _known_garbage_bytes >= known_garbage_bytes, "invariant" ); _known_garbage_bytes -= known_garbage_bytes; size_t heap_bytes = _g1->capacity(); _known_garbage_ratio = (double) _known_garbage_bytes / (double) heap_bytes; } G1MMUTracker* mmu_tracker() { return _mmu_tracker; } double predict_init_time_ms() { return get_new_prediction(_concurrent_mark_init_times_ms); } double predict_remark_time_ms() { return get_new_prediction(_concurrent_mark_remark_times_ms); } double predict_cleanup_time_ms() { return get_new_prediction(_concurrent_mark_cleanup_times_ms); } // Returns an estimate of the survival rate of the region at yg-age // "yg_age". double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) { TruncatedSeq* seq = surv_rate_group->get_seq(age); if (seq->num() == 0) gclog_or_tty->print("BARF! age is %d", age); guarantee( seq->num() > 0, "invariant" ); double pred = get_new_prediction(seq); if (pred > 1.0) pred = 1.0; return pred; } double predict_yg_surv_rate(int age) { return predict_yg_surv_rate(age, _short_lived_surv_rate_group); } double accum_yg_surv_rate_pred(int age) { return _short_lived_surv_rate_group->accum_surv_rate_pred(age); } protected: void print_stats (int level, const char* str, double value); void print_stats (int level, const char* str, int value); void print_par_stats (int level, const char* str, double* data) { print_par_stats(level, str, data, true); } void print_par_stats (int level, const char* str, double* data, bool summary); void print_par_buffers (int level, const char* str, double* data, bool summary); void check_other_times(int level, NumberSeq* other_times_ms, NumberSeq* calc_other_times_ms) const; void print_summary (PauseSummary* stats) const; void print_abandoned_summary(PauseSummary* non_pop_summary, PauseSummary* pop_summary) const; void print_summary (int level, const char* str, NumberSeq* seq) const; void print_summary_sd (int level, const char* str, NumberSeq* seq) const; double avg_value (double* data); double max_value (double* data); double sum_of_values (double* data); double max_sum (double* data1, double* data2); int _last_satb_drain_processed_buffers; int _last_update_rs_processed_buffers; double _last_pause_time_ms; size_t _bytes_in_to_space_before_gc; size_t _bytes_in_to_space_after_gc; size_t bytes_in_to_space_during_gc() { return _bytes_in_to_space_after_gc - _bytes_in_to_space_before_gc; } size_t _bytes_in_collection_set_before_gc; // Used to count used bytes in CS. friend class CountCSClosure; // Statistics kept per GC stoppage, pause or full. TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec; // We track markings. int _num_markings; double _mark_thread_startup_sec; // Time at startup of marking thread // Add a new GC of the given duration and end time to the record. void update_recent_gc_times(double end_time_sec, double elapsed_ms); // The head of the list (via "next_in_collection_set()") representing the // current collection set. HeapRegion* _collection_set; size_t _collection_set_size; size_t _collection_set_bytes_used_before; // Info about marking. int _n_marks; // Sticky at 2, so we know when we've done at least 2. // The number of collection pauses at the end of the last mark. size_t _n_pauses_at_mark_end; // ==== This section is for stats related to starting Conc Refinement on time. size_t _conc_refine_enabled; size_t _conc_refine_zero_traversals; size_t _conc_refine_max_traversals; // In # of heap regions. size_t _conc_refine_current_delta; // At the beginning of a collection pause, update the variables above, // especially the "delta". void update_conc_refine_data(); // ==== // Stash a pointer to the g1 heap. G1CollectedHeap* _g1; // The average time in ms per collection pause, averaged over recent pauses. double recent_avg_time_for_pauses_ms(); // The average time in ms for processing CollectedHeap strong roots, per // collection pause, averaged over recent pauses. double recent_avg_time_for_CH_strong_ms(); // The average time in ms for processing the G1 remembered set, per // pause, averaged over recent pauses. double recent_avg_time_for_G1_strong_ms(); // The average time in ms for "evacuating followers", per pause, averaged // over recent pauses. double recent_avg_time_for_evac_ms(); // The number of "recent" GCs recorded in the number sequences int number_of_recent_gcs(); // The average survival ratio, computed by the total number of bytes // suriviving / total number of bytes before collection over the last // several recent pauses. double recent_avg_survival_fraction(); // The survival fraction of the most recent pause; if there have been no // pauses, returns 1.0. double last_survival_fraction(); // Returns a "conservative" estimate of the recent survival rate, i.e., // one that may be higher than "recent_avg_survival_fraction". // This is conservative in several ways: // If there have been few pauses, it will assume a potential high // variance, and err on the side of caution. // It puts a lower bound (currently 0.1) on the value it will return. // To try to detect phase changes, if the most recent pause ("latest") has a // higher-than average ("avg") survival rate, it returns that rate. // "work" version is a utility function; young is restricted to young regions. double conservative_avg_survival_fraction_work(double avg, double latest); // The arguments are the two sequences that keep track of the number of bytes // surviving and the total number of bytes before collection, resp., // over the last evereal recent pauses // Returns the survival rate for the category in the most recent pause. // If there have been no pauses, returns 1.0. double last_survival_fraction_work(TruncatedSeq* surviving, TruncatedSeq* before); // The arguments are the two sequences that keep track of the number of bytes // surviving and the total number of bytes before collection, resp., // over the last several recent pauses // Returns the average survival ration over the last several recent pauses // If there have been no pauses, return 1.0 double recent_avg_survival_fraction_work(TruncatedSeq* surviving, TruncatedSeq* before); double conservative_avg_survival_fraction() { double avg = recent_avg_survival_fraction(); double latest = last_survival_fraction(); return conservative_avg_survival_fraction_work(avg, latest); } // The ratio of gc time to elapsed time, computed over recent pauses. double _recent_avg_pause_time_ratio; double recent_avg_pause_time_ratio() { return _recent_avg_pause_time_ratio; } // Number of pauses between concurrent marking. size_t _pauses_btwn_concurrent_mark; size_t _n_marks_since_last_pause; // True iff CM has been initiated. bool _conc_mark_initiated; // True iff CM should be initiated bool _should_initiate_conc_mark; bool _should_revert_to_full_young_gcs; bool _last_full_young_gc; // This set of variables tracks the collector efficiency, in order to // determine whether we should initiate a new marking. double _cur_mark_stop_world_time_ms; double _mark_init_start_sec; double _mark_remark_start_sec; double _mark_cleanup_start_sec; double _mark_closure_time_ms; void calculate_young_list_min_length(); void calculate_young_list_target_config(); void calculate_young_list_target_config(size_t rs_lengths); size_t calculate_optimal_so_length(size_t young_list_length); public: G1CollectorPolicy(); virtual G1CollectorPolicy* as_g1_policy() { return this; } virtual CollectorPolicy::Name kind() { return CollectorPolicy::G1CollectorPolicyKind; } void check_prediction_validity(); size_t bytes_in_collection_set() { return _bytes_in_collection_set_before_gc; } size_t bytes_in_to_space() { return bytes_in_to_space_during_gc(); } unsigned calc_gc_alloc_time_stamp() { return _all_pause_times_ms->num() + 1; } protected: // Count the number of bytes used in the CS. void count_CS_bytes_used(); // Together these do the base cleanup-recording work. Subclasses might // want to put something between them. void record_concurrent_mark_cleanup_end_work1(size_t freed_bytes, size_t max_live_bytes); void record_concurrent_mark_cleanup_end_work2(); public: virtual void init(); // Create jstat counters for the policy. virtual void initialize_gc_policy_counters(); virtual HeapWord* mem_allocate_work(size_t size, bool is_tlab, bool* gc_overhead_limit_was_exceeded); // This method controls how a collector handles one or more // of its generations being fully allocated. virtual HeapWord* satisfy_failed_allocation(size_t size, bool is_tlab); BarrierSet::Name barrier_set_name() { return BarrierSet::G1SATBCTLogging; } GenRemSet::Name rem_set_name() { return GenRemSet::CardTable; } // The number of collection pauses so far. long n_pauses() const { return _n_pauses; } // Update the heuristic info to record a collection pause of the given // start time, where the given number of bytes were used at the start. // This may involve changing the desired size of a collection set. virtual void record_stop_world_start(); virtual void record_collection_pause_start(double start_time_sec, size_t start_used); virtual void record_popular_pause_preamble_start(); virtual void record_popular_pause_preamble_end(); // Must currently be called while the world is stopped. virtual void record_concurrent_mark_init_start(); virtual void record_concurrent_mark_init_end(); void record_concurrent_mark_init_end_pre(double mark_init_elapsed_time_ms); void record_mark_closure_time(double mark_closure_time_ms); virtual void record_concurrent_mark_remark_start(); virtual void record_concurrent_mark_remark_end(); virtual void record_concurrent_mark_cleanup_start(); virtual void record_concurrent_mark_cleanup_end(size_t freed_bytes, size_t max_live_bytes); virtual void record_concurrent_mark_cleanup_completed(); virtual void record_concurrent_pause(); virtual void record_concurrent_pause_end(); virtual void record_collection_pause_end_CH_strong_roots(); virtual void record_collection_pause_end_G1_strong_roots(); virtual void record_collection_pause_end(bool popular, bool abandoned); // Record the fact that a full collection occurred. virtual void record_full_collection_start(); virtual void record_full_collection_end(); void record_ext_root_scan_time(int worker_i, double ms) { _par_last_ext_root_scan_times_ms[worker_i] = ms; } void record_mark_stack_scan_time(int worker_i, double ms) { _par_last_mark_stack_scan_times_ms[worker_i] = ms; } void record_scan_only_time(int worker_i, double ms, int n) { _par_last_scan_only_times_ms[worker_i] = ms; _par_last_scan_only_regions_scanned[worker_i] = (double) n; } void record_satb_drain_time(double ms) { _cur_satb_drain_time_ms = ms; _satb_drain_time_set = true; } void record_satb_drain_processed_buffers (int processed_buffers) { _last_satb_drain_processed_buffers = processed_buffers; } void record_mod_union_time(double ms) { _all_mod_union_times_ms->add(ms); } void record_update_rs_start_time(int thread, double ms) { _par_last_update_rs_start_times_ms[thread] = ms; } void record_update_rs_time(int thread, double ms) { _par_last_update_rs_times_ms[thread] = ms; } void record_update_rs_processed_buffers (int thread, double processed_buffers) { _par_last_update_rs_processed_buffers[thread] = processed_buffers; } void record_scan_rs_start_time(int thread, double ms) { _par_last_scan_rs_start_times_ms[thread] = ms; } void record_scan_rs_time(int thread, double ms) { _par_last_scan_rs_times_ms[thread] = ms; } void record_scan_new_refs_time(int thread, double ms) { _par_last_scan_new_refs_times_ms[thread] = ms; } double get_scan_new_refs_time(int thread) { return _par_last_scan_new_refs_times_ms[thread]; } void reset_obj_copy_time(int thread) { _par_last_obj_copy_times_ms[thread] = 0.0; } void reset_obj_copy_time() { reset_obj_copy_time(0); } void record_obj_copy_time(int thread, double ms) { _par_last_obj_copy_times_ms[thread] += ms; } void record_obj_copy_time(double ms) { record_obj_copy_time(0, ms); } void record_termination_time(int thread, double ms) { _par_last_termination_times_ms[thread] = ms; } void record_termination_time(double ms) { record_termination_time(0, ms); } void record_pause_time(double ms) { _last_pause_time_ms = ms; } void record_clear_ct_time(double ms) { _cur_clear_ct_time_ms = ms; } void record_par_time(double ms) { _cur_collection_par_time_ms = ms; } void record_aux_start_time(int i) { guarantee(i < _aux_num, "should be within range"); _cur_aux_start_times_ms[i] = os::elapsedTime() * 1000.0; } void record_aux_end_time(int i) { guarantee(i < _aux_num, "should be within range"); double ms = os::elapsedTime() * 1000.0 - _cur_aux_start_times_ms[i]; _cur_aux_times_set[i] = true; _cur_aux_times_ms[i] += ms; } void record_pop_compute_rc_start(); void record_pop_compute_rc_end(); void record_pop_evac_start(); void record_pop_evac_end(); // Record the fact that "bytes" bytes allocated in a region. void record_before_bytes(size_t bytes); void record_after_bytes(size_t bytes); // Returns "true" if this is a good time to do a collection pause. // The "word_size" argument, if non-zero, indicates the size of an // allocation request that is prompting this query. virtual bool should_do_collection_pause(size_t word_size) = 0; // Choose a new collection set. Marks the chosen regions as being // "in_collection_set", and links them together. The head and number of // the collection set are available via access methods. // If "pop_region" is non-NULL, it is a popular region that has already // been added to the collection set. virtual void choose_collection_set(HeapRegion* pop_region = NULL) = 0; void clear_collection_set() { _collection_set = NULL; } // The head of the list (via "next_in_collection_set()") representing the // current collection set. HeapRegion* collection_set() { return _collection_set; } // Sets the collection set to the given single region. virtual void set_single_region_collection_set(HeapRegion* hr); // The number of elements in the current collection set. size_t collection_set_size() { return _collection_set_size; } // Add "hr" to the CS. void add_to_collection_set(HeapRegion* hr); bool should_initiate_conc_mark() { return _should_initiate_conc_mark; } void set_should_initiate_conc_mark() { _should_initiate_conc_mark = true; } void unset_should_initiate_conc_mark(){ _should_initiate_conc_mark = false; } void checkpoint_conc_overhead(); // If an expansion would be appropriate, because recent GC overhead had // exceeded the desired limit, return an amount to expand by. virtual size_t expansion_amount(); // note start of mark thread void note_start_of_mark_thread(); // The marked bytes of the "r" has changed; reclassify it's desirability // for marking. Also asserts that "r" is eligible for a CS. virtual void note_change_in_marked_bytes(HeapRegion* r) = 0; #ifndef PRODUCT // Check any appropriate marked bytes info, asserting false if // something's wrong, else returning "true". virtual bool assertMarkedBytesDataOK() = 0; #endif // Print tracing information. void print_tracing_info() const; // Print stats on young survival ratio void print_yg_surv_rate_info() const; void finished_recalculating_age_indexes(bool is_survivors) { if (is_survivors) { _survivor_surv_rate_group->finished_recalculating_age_indexes(); } else { _short_lived_surv_rate_group->finished_recalculating_age_indexes(); } // do that for any other surv rate groups } bool should_add_next_region_to_young_list(); bool in_young_gc_mode() { return _in_young_gc_mode; } void set_in_young_gc_mode(bool in_young_gc_mode) { _in_young_gc_mode = in_young_gc_mode; } bool full_young_gcs() { return _full_young_gcs; } void set_full_young_gcs(bool full_young_gcs) { _full_young_gcs = full_young_gcs; } bool adaptive_young_list_length() { return _adaptive_young_list_length; } void set_adaptive_young_list_length(bool adaptive_young_list_length) { _adaptive_young_list_length = adaptive_young_list_length; } inline double get_gc_eff_factor() { double ratio = _known_garbage_ratio; double square = ratio * ratio; // square = square * square; double ret = square * 9.0 + 1.0; #if 0 gclog_or_tty->print_cr("ratio = %1.2lf, ret = %1.2lf", ratio, ret); #endif // 0 guarantee(0.0 <= ret && ret < 10.0, "invariant!"); return ret; } // // Survivor regions policy. // protected: // Current tenuring threshold, set to 0 if the collector reaches the // maximum amount of suvivors regions. int _tenuring_threshold; // The limit on the number of regions allocated for survivors. size_t _max_survivor_regions; // The amount of survor regions after a collection. size_t _recorded_survivor_regions; // List of survivor regions. HeapRegion* _recorded_survivor_head; HeapRegion* _recorded_survivor_tail; ageTable _survivors_age_table; public: inline GCAllocPurpose evacuation_destination(HeapRegion* src_region, int age, size_t word_sz) { if (age < _tenuring_threshold && src_region->is_young()) { return GCAllocForSurvived; } else { return GCAllocForTenured; } } inline bool track_object_age(GCAllocPurpose purpose) { return purpose == GCAllocForSurvived; } inline GCAllocPurpose alternative_purpose(int purpose) { return GCAllocForTenured; } static const size_t REGIONS_UNLIMITED = ~(size_t)0; size_t max_regions(int purpose); // The limit on regions for a particular purpose is reached. void note_alloc_region_limit_reached(int purpose) { if (purpose == GCAllocForSurvived) { _tenuring_threshold = 0; } } void note_start_adding_survivor_regions() { _survivor_surv_rate_group->start_adding_regions(); } void note_stop_adding_survivor_regions() { _survivor_surv_rate_group->stop_adding_regions(); } void record_survivor_regions(size_t regions, HeapRegion* head, HeapRegion* tail) { _recorded_survivor_regions = regions; _recorded_survivor_head = head; _recorded_survivor_tail = tail; } void record_thread_age_table(ageTable* age_table) { _survivors_age_table.merge_par(age_table); } // Calculates survivor space parameters. void calculate_survivors_policy(); }; // This encapsulates a particular strategy for a g1 Collector. // // Start a concurrent mark when our heap size is n bytes // greater then our heap size was at the last concurrent // mark. Where n is a function of the CMSTriggerRatio // and the MinHeapFreeRatio. // // Start a g1 collection pause when we have allocated the // average number of bytes currently being freed in // a collection, but only if it is at least one region // full // // Resize Heap based on desired // allocation space, where desired allocation space is // a function of survival rate and desired future to size. // // Choose collection set by first picking all older regions // which have a survival rate which beats our projected young // survival rate. Then fill out the number of needed regions // with young regions. class G1CollectorPolicy_BestRegionsFirst: public G1CollectorPolicy { CollectionSetChooser* _collectionSetChooser; // If the estimated is less then desirable, resize if possible. void expand_if_possible(size_t numRegions); virtual void choose_collection_set(HeapRegion* pop_region = NULL); virtual void record_collection_pause_start(double start_time_sec, size_t start_used); virtual void record_concurrent_mark_cleanup_end(size_t freed_bytes, size_t max_live_bytes); virtual void record_full_collection_end(); public: G1CollectorPolicy_BestRegionsFirst() { _collectionSetChooser = new CollectionSetChooser(); } void record_collection_pause_end(bool popular, bool abandoned); bool should_do_collection_pause(size_t word_size); virtual void set_single_region_collection_set(HeapRegion* hr); // This is not needed any more, after the CSet choosing code was // changed to use the pause prediction work. But let's leave the // hook in just in case. void note_change_in_marked_bytes(HeapRegion* r) { } #ifndef PRODUCT bool assertMarkedBytesDataOK(); #endif }; // This should move to some place more general... // If we have "n" measurements, and we've kept track of their "sum" and the // "sum_of_squares" of the measurements, this returns the variance of the // sequence. inline double variance(int n, double sum_of_squares, double sum) { double n_d = (double)n; double avg = sum/n_d; return (sum_of_squares - 2.0 * avg * sum + n_d * avg * avg) / n_d; } // Local Variables: *** // c-indentation-style: gnu *** // End: ***