graal-compiler: src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp comparison

comparison src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp @ 342:37f87013dfd8

6711316: Open source the Garbage-First garbage collector Summary: First mercurial integration of the code for the Garbage-First garbage collector. Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr

author	ysr
date	Thu, 05 Jun 2008 15:57:56 -0700
parents
children	58054a18d735

comparison

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-:0b27f3512f9e
+:37f87013dfd8
+/*
+* 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 {
+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 {
+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 {
+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);
+}
+// </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) {
+TruncatedSeq* seq = _short_lived_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 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();
+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() {
+_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;
+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;
+}
+uint 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();
+}
+};
+// 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: ***

Mercurial > hg > graal-compiler

comparison src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp @ 342:37f87013dfd8