Mercurial > hg > truffle
view src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp @ 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 | 1e458753107d |
children | 0fbdb4381b99 3698e8f47799 |
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/* * Copyright 2001-2008 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. * */ #include "incls/_precompiled.incl" #include "incls/_g1CollectorPolicy.cpp.incl" #define PREDICTIONS_VERBOSE 0 // <NEW PREDICTION> // Different defaults for different number of GC threads // They were chosen by running GCOld and SPECjbb on debris with different // numbers of GC threads and choosing them based on the results // all the same static double rs_length_diff_defaults[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 }; static double cost_per_card_ms_defaults[] = { 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015 }; static double cost_per_scan_only_region_ms_defaults[] = { 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 }; // all the same static double fully_young_cards_per_entry_ratio_defaults[] = { 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 }; static double cost_per_entry_ms_defaults[] = { 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005 }; static double cost_per_byte_ms_defaults[] = { 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009 }; // these should be pretty consistent static double constant_other_time_ms_defaults[] = { 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0 }; static double young_other_cost_per_region_ms_defaults[] = { 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1 }; static double non_young_other_cost_per_region_ms_defaults[] = { 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30 }; // </NEW PREDICTION> G1CollectorPolicy::G1CollectorPolicy() : _parallel_gc_threads((ParallelGCThreads > 0) ? ParallelGCThreads : 1), _n_pauses(0), _recent_CH_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), _recent_G1_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), _recent_evac_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), _recent_pause_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), _recent_rs_sizes(new TruncatedSeq(NumPrevPausesForHeuristics)), _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), _all_pause_times_ms(new NumberSeq()), _stop_world_start(0.0), _all_stop_world_times_ms(new NumberSeq()), _all_yield_times_ms(new NumberSeq()), _all_mod_union_times_ms(new NumberSeq()), _non_pop_summary(new NonPopSummary()), _pop_summary(new PopSummary()), _non_pop_abandoned_summary(new NonPopAbandonedSummary()), _pop_abandoned_summary(new PopAbandonedSummary()), _cur_clear_ct_time_ms(0.0), _region_num_young(0), _region_num_tenured(0), _prev_region_num_young(0), _prev_region_num_tenured(0), _aux_num(10), _all_aux_times_ms(new NumberSeq[_aux_num]), _cur_aux_start_times_ms(new double[_aux_num]), _cur_aux_times_ms(new double[_aux_num]), _cur_aux_times_set(new bool[_aux_num]), _pop_compute_rc_start(0.0), _pop_evac_start(0.0), _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)), // <NEW PREDICTION> _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)), _prev_collection_pause_end_ms(0.0), _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)), _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)), _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)), _cost_per_scan_only_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)), _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)), _partially_young_cards_per_entry_ratio_seq( new TruncatedSeq(TruncatedSeqLength)), _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)), _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)), _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)), _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)), _cost_per_scan_only_region_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)), _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)), _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)), _non_young_other_cost_per_region_ms_seq( new TruncatedSeq(TruncatedSeqLength)), _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)), _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)), _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)), _pause_time_target_ms((double) G1MaxPauseTimeMS), // </NEW PREDICTION> _in_young_gc_mode(false), _full_young_gcs(true), _full_young_pause_num(0), _partial_young_pause_num(0), _during_marking(false), _in_marking_window(false), _in_marking_window_im(false), _known_garbage_ratio(0.0), _known_garbage_bytes(0), _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)), _target_pause_time_ms(-1.0), _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)), _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)), _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)), _recent_avg_pause_time_ratio(0.0), _num_markings(0), _n_marks(0), _n_pauses_at_mark_end(0), _all_full_gc_times_ms(new NumberSeq()), _conc_refine_enabled(0), _conc_refine_zero_traversals(0), _conc_refine_max_traversals(0), _conc_refine_current_delta(G1ConcRefineInitialDelta), // G1PausesBtwnConcMark defaults to -1 // so the hack is to do the cast QQQ FIXME _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark), _n_marks_since_last_pause(0), _conc_mark_initiated(false), _should_initiate_conc_mark(false), _should_revert_to_full_young_gcs(false), _last_full_young_gc(false), _prev_collection_pause_used_at_end_bytes(0), _collection_set(NULL), #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away #pragma warning( disable:4355 ) // 'this' : used in base member initializer list #endif // _MSC_VER _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived", G1YoungSurvRateNumRegionsSummary)), _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor", G1YoungSurvRateNumRegionsSummary)), // add here any more surv rate groups _recorded_survivor_regions(0), _recorded_survivor_head(NULL), _recorded_survivor_tail(NULL), _survivors_age_table(true) { _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime()); _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0; _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads]; _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads]; _par_last_scan_only_times_ms = new double[_parallel_gc_threads]; _par_last_scan_only_regions_scanned = new double[_parallel_gc_threads]; _par_last_update_rs_start_times_ms = new double[_parallel_gc_threads]; _par_last_update_rs_times_ms = new double[_parallel_gc_threads]; _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads]; _par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads]; _par_last_scan_rs_times_ms = new double[_parallel_gc_threads]; _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads]; _par_last_obj_copy_times_ms = new double[_parallel_gc_threads]; _par_last_termination_times_ms = new double[_parallel_gc_threads]; // we store the data from the first pass during popularity pauses _pop_par_last_update_rs_start_times_ms = new double[_parallel_gc_threads]; _pop_par_last_update_rs_times_ms = new double[_parallel_gc_threads]; _pop_par_last_update_rs_processed_buffers = new double[_parallel_gc_threads]; _pop_par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads]; _pop_par_last_scan_rs_times_ms = new double[_parallel_gc_threads]; _pop_par_last_closure_app_times_ms = new double[_parallel_gc_threads]; // start conservatively _expensive_region_limit_ms = 0.5 * (double) G1MaxPauseTimeMS; // <NEW PREDICTION> int index; if (ParallelGCThreads == 0) index = 0; else if (ParallelGCThreads > 8) index = 7; else index = ParallelGCThreads - 1; _pending_card_diff_seq->add(0.0); _rs_length_diff_seq->add(rs_length_diff_defaults[index]); _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]); _cost_per_scan_only_region_ms_seq->add( cost_per_scan_only_region_ms_defaults[index]); _fully_young_cards_per_entry_ratio_seq->add( fully_young_cards_per_entry_ratio_defaults[index]); _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]); _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]); _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]); _young_other_cost_per_region_ms_seq->add( young_other_cost_per_region_ms_defaults[index]); _non_young_other_cost_per_region_ms_seq->add( non_young_other_cost_per_region_ms_defaults[index]); // </NEW PREDICTION> double time_slice = (double) G1TimeSliceMS / 1000.0; double max_gc_time = (double) G1MaxPauseTimeMS / 1000.0; guarantee(max_gc_time < time_slice, "Max GC time should not be greater than the time slice"); _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time); _sigma = (double) G1ConfidencePerc / 100.0; // start conservatively (around 50ms is about right) _concurrent_mark_init_times_ms->add(0.05); _concurrent_mark_remark_times_ms->add(0.05); _concurrent_mark_cleanup_times_ms->add(0.20); _tenuring_threshold = MaxTenuringThreshold; if (G1UseSurvivorSpace) { // if G1FixedSurvivorSpaceSize is 0 which means the size is not // fixed, then _max_survivor_regions will be calculated at // calculate_young_list_target_config during initialization _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes; } else { _max_survivor_regions = 0; } initialize_all(); } // Increment "i", mod "len" static void inc_mod(int& i, int len) { i++; if (i == len) i = 0; } void G1CollectorPolicy::initialize_flags() { set_min_alignment(HeapRegion::GrainBytes); set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name())); if (SurvivorRatio < 1) { vm_exit_during_initialization("Invalid survivor ratio specified"); } CollectorPolicy::initialize_flags(); } void G1CollectorPolicy::init() { // Set aside an initial future to_space. _g1 = G1CollectedHeap::heap(); size_t regions = Universe::heap()->capacity() / HeapRegion::GrainBytes; assert(Heap_lock->owned_by_self(), "Locking discipline."); if (G1SteadyStateUsed < 50) { vm_exit_during_initialization("G1SteadyStateUsed must be at least 50%."); } if (UseConcMarkSweepGC) { vm_exit_during_initialization("-XX:+UseG1GC is incompatible with " "-XX:+UseConcMarkSweepGC."); } initialize_gc_policy_counters(); if (G1Gen) { _in_young_gc_mode = true; if (G1YoungGenSize == 0) { set_adaptive_young_list_length(true); _young_list_fixed_length = 0; } else { set_adaptive_young_list_length(false); _young_list_fixed_length = (G1YoungGenSize / HeapRegion::GrainBytes); } _free_regions_at_end_of_collection = _g1->free_regions(); _scan_only_regions_at_end_of_collection = 0; calculate_young_list_min_length(); guarantee( _young_list_min_length == 0, "invariant, not enough info" ); calculate_young_list_target_config(); } else { _young_list_fixed_length = 0; _in_young_gc_mode = false; } } // Create the jstat counters for the policy. void G1CollectorPolicy::initialize_gc_policy_counters() { _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen); } void G1CollectorPolicy::calculate_young_list_min_length() { _young_list_min_length = 0; if (!adaptive_young_list_length()) return; if (_alloc_rate_ms_seq->num() > 3) { double now_sec = os::elapsedTime(); double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0; double alloc_rate_ms = predict_alloc_rate_ms(); int min_regions = (int) ceil(alloc_rate_ms * when_ms); int current_region_num = (int) _g1->young_list_length(); _young_list_min_length = min_regions + current_region_num; } } void G1CollectorPolicy::calculate_young_list_target_config() { if (adaptive_young_list_length()) { size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq); calculate_young_list_target_config(rs_lengths); } else { if (full_young_gcs()) _young_list_target_length = _young_list_fixed_length; else _young_list_target_length = _young_list_fixed_length / 2; _young_list_target_length = MAX2(_young_list_target_length, (size_t)1); size_t so_length = calculate_optimal_so_length(_young_list_target_length); guarantee( so_length < _young_list_target_length, "invariant" ); _young_list_so_prefix_length = so_length; } calculate_survivors_policy(); } // This method calculate the optimal scan-only set for a fixed young // gen size. I couldn't work out how to reuse the more elaborate one, // i.e. calculate_young_list_target_config(rs_length), as the loops are // fundamentally different (the other one finds a config for different // S-O lengths, whereas here we need to do the opposite). size_t G1CollectorPolicy::calculate_optimal_so_length( size_t young_list_length) { if (!G1UseScanOnlyPrefix) return 0; if (_all_pause_times_ms->num() < 3) { // we won't use a scan-only set at the beginning to allow the rest // of the predictors to warm up return 0; } if (_cost_per_scan_only_region_ms_seq->num() < 3) { // then, we'll only set the S-O set to 1 for a little bit of time, // to get enough information on the scanning cost return 1; } size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq); size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq); size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff(); size_t scanned_cards; if (full_young_gcs()) scanned_cards = predict_young_card_num(adj_rs_lengths); else scanned_cards = predict_non_young_card_num(adj_rs_lengths); double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards); size_t so_length = 0; double max_gc_eff = 0.0; for (size_t i = 0; i < young_list_length; ++i) { double gc_eff = 0.0; double pause_time_ms = 0.0; predict_gc_eff(young_list_length, i, base_time_ms, &gc_eff, &pause_time_ms); if (gc_eff > max_gc_eff) { max_gc_eff = gc_eff; so_length = i; } } // set it to 95% of the optimal to make sure we sample the "area" // around the optimal length to get up-to-date survival rate data return so_length * 950 / 1000; } // This is a really cool piece of code! It finds the best // target configuration (young length / scan-only prefix length) so // that GC efficiency is maximized and that we also meet a pause // time. It's a triple nested loop. These loops are explained below // from the inside-out :-) // // (a) The innermost loop will try to find the optimal young length // for a fixed S-O length. It uses a binary search to speed up the // process. We assume that, for a fixed S-O length, as we add more // young regions to the CSet, the GC efficiency will only go up (I'll // skip the proof). So, using a binary search to optimize this process // makes perfect sense. // // (b) The middle loop will fix the S-O length before calling the // innermost one. It will vary it between two parameters, increasing // it by a given increment. // // (c) The outermost loop will call the middle loop three times. // (1) The first time it will explore all possible S-O length values // from 0 to as large as it can get, using a coarse increment (to // quickly "home in" to where the optimal seems to be). // (2) The second time it will explore the values around the optimal // that was found by the first iteration using a fine increment. // (3) Once the optimal config has been determined by the second // iteration, we'll redo the calculation, but setting the S-O length // to 95% of the optimal to make sure we sample the "area" // around the optimal length to get up-to-date survival rate data // // Termination conditions for the iterations are several: the pause // time is over the limit, we do not have enough to-space, etc. void G1CollectorPolicy::calculate_young_list_target_config(size_t rs_lengths) { guarantee( adaptive_young_list_length(), "pre-condition" ); double start_time_sec = os::elapsedTime(); size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1MinReservePerc); min_reserve_perc = MIN2((size_t) 50, min_reserve_perc); size_t reserve_regions = (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0); if (full_young_gcs() && _free_regions_at_end_of_collection > 0) { // we are in fully-young mode and there are free regions in the heap double survivor_regions_evac_time = predict_survivor_regions_evac_time(); size_t min_so_length = 0; size_t max_so_length = 0; if (G1UseScanOnlyPrefix) { if (_all_pause_times_ms->num() < 3) { // we won't use a scan-only set at the beginning to allow the rest // of the predictors to warm up min_so_length = 0; max_so_length = 0; } else if (_cost_per_scan_only_region_ms_seq->num() < 3) { // then, we'll only set the S-O set to 1 for a little bit of time, // to get enough information on the scanning cost min_so_length = 1; max_so_length = 1; } else if (_in_marking_window || _last_full_young_gc) { // no S-O prefix during a marking phase either, as at the end // of the marking phase we'll have to use a very small young // length target to fill up the rest of the CSet with // non-young regions and, if we have lots of scan-only regions // left-over, we will not be able to add any more non-young // regions. min_so_length = 0; max_so_length = 0; } else { // this is the common case; we'll never reach the maximum, we // one of the end conditions will fire well before that // (hopefully!) min_so_length = 0; max_so_length = _free_regions_at_end_of_collection - 1; } } else { // no S-O prefix, as the switch is not set, but we still need to // do one iteration to calculate the best young target that // meets the pause time; this way we reuse the same code instead // of replicating it min_so_length = 0; max_so_length = 0; } double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0; size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq); size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff(); size_t scanned_cards; if (full_young_gcs()) scanned_cards = predict_young_card_num(adj_rs_lengths); else scanned_cards = predict_non_young_card_num(adj_rs_lengths); // calculate this once, so that we don't have to recalculate it in // the innermost loop double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards) + survivor_regions_evac_time; // the result size_t final_young_length = 0; size_t final_so_length = 0; double final_gc_eff = 0.0; // we'll also keep track of how many times we go into the inner loop // this is for profiling reasons size_t calculations = 0; // this determines which of the three iterations the outer loop is in typedef enum { pass_type_coarse, pass_type_fine, pass_type_final } pass_type_t; // range of the outer loop's iteration size_t from_so_length = min_so_length; size_t to_so_length = max_so_length; guarantee( from_so_length <= to_so_length, "invariant" ); // this will keep the S-O length that's found by the second // iteration of the outer loop; we'll keep it just in case the third // iteration fails to find something size_t fine_so_length = 0; // the increment step for the coarse (first) iteration size_t so_coarse_increments = 5; // the common case, we'll start with the coarse iteration pass_type_t pass = pass_type_coarse; size_t so_length_incr = so_coarse_increments; if (from_so_length == to_so_length) { // not point in doing the coarse iteration, we'll go directly into // the fine one (we essentially trying to find the optimal young // length for a fixed S-O length). so_length_incr = 1; pass = pass_type_final; } else if (to_so_length - from_so_length < 3 * so_coarse_increments) { // again, the range is too short so no point in foind the coarse // iteration either so_length_incr = 1; pass = pass_type_fine; } bool done = false; // this is the outermost loop while (!done) { #ifdef TRACE_CALC_YOUNG_CONFIG // leave this in for debugging, just in case gclog_or_tty->print_cr("searching between " SIZE_FORMAT " and " SIZE_FORMAT ", incr " SIZE_FORMAT ", pass %s", from_so_length, to_so_length, so_length_incr, (pass == pass_type_coarse) ? "coarse" : (pass == pass_type_fine) ? "fine" : "final"); #endif // TRACE_CALC_YOUNG_CONFIG size_t so_length = from_so_length; size_t init_free_regions = MAX2((size_t)0, _free_regions_at_end_of_collection + _scan_only_regions_at_end_of_collection - reserve_regions); // this determines whether a configuration was found bool gc_eff_set = false; // this is the middle loop while (so_length <= to_so_length) { // base time, which excludes region-related time; again we // calculate it once to avoid recalculating it in the // innermost loop double base_time_with_so_ms = base_time_ms + predict_scan_only_time_ms(so_length); // it's already over the pause target, go around if (base_time_with_so_ms > target_pause_time_ms) break; size_t starting_young_length = so_length+1; // we make sure that the short young length that makes sense // (one more than the S-O length) is feasible size_t min_young_length = starting_young_length; double min_gc_eff; bool min_ok; ++calculations; min_ok = predict_gc_eff(min_young_length, so_length, base_time_with_so_ms, init_free_regions, target_pause_time_ms, &min_gc_eff); if (min_ok) { // the shortest young length is indeed feasible; we'll know // set up the max young length and we'll do a binary search // between min_young_length and max_young_length size_t max_young_length = _free_regions_at_end_of_collection - 1; double max_gc_eff = 0.0; bool max_ok = false; // the innermost loop! (finally!) while (max_young_length > min_young_length) { // we'll make sure that min_young_length is always at a // feasible config guarantee( min_ok, "invariant" ); ++calculations; max_ok = predict_gc_eff(max_young_length, so_length, base_time_with_so_ms, init_free_regions, target_pause_time_ms, &max_gc_eff); size_t diff = (max_young_length - min_young_length) / 2; if (max_ok) { min_young_length = max_young_length; min_gc_eff = max_gc_eff; min_ok = true; } max_young_length = min_young_length + diff; } // the innermost loop found a config guarantee( min_ok, "invariant" ); if (min_gc_eff > final_gc_eff) { // it's the best config so far, so we'll keep it final_gc_eff = min_gc_eff; final_young_length = min_young_length; final_so_length = so_length; gc_eff_set = true; } } // incremental the fixed S-O length and go around so_length += so_length_incr; } // this is the end of the outermost loop and we need to decide // what to do during the next iteration if (pass == pass_type_coarse) { // we just did the coarse pass (first iteration) if (!gc_eff_set) // we didn't find a feasible config so we'll just bail out; of // course, it might be the case that we missed it; but I'd say // it's a bit unlikely done = true; else { // We did find a feasible config with optimal GC eff during // the first pass. So the second pass we'll only consider the // S-O lengths around that config with a fine increment. guarantee( so_length_incr == so_coarse_increments, "invariant" ); guarantee( final_so_length >= min_so_length, "invariant" ); #ifdef TRACE_CALC_YOUNG_CONFIG // leave this in for debugging, just in case gclog_or_tty->print_cr(" coarse pass: SO length " SIZE_FORMAT, final_so_length); #endif // TRACE_CALC_YOUNG_CONFIG from_so_length = (final_so_length - min_so_length > so_coarse_increments) ? final_so_length - so_coarse_increments + 1 : min_so_length; to_so_length = (max_so_length - final_so_length > so_coarse_increments) ? final_so_length + so_coarse_increments - 1 : max_so_length; pass = pass_type_fine; so_length_incr = 1; } } else if (pass == pass_type_fine) { // we just finished the second pass if (!gc_eff_set) { // we didn't find a feasible config (yes, it's possible; // notice that, sometimes, we go directly into the fine // iteration and skip the coarse one) so we bail out done = true; } else { // We did find a feasible config with optimal GC eff guarantee( so_length_incr == 1, "invariant" ); if (final_so_length == 0) { // The config is of an empty S-O set, so we'll just bail out done = true; } else { // we'll go around once more, setting the S-O length to 95% // of the optimal size_t new_so_length = 950 * final_so_length / 1000; #ifdef TRACE_CALC_YOUNG_CONFIG // leave this in for debugging, just in case gclog_or_tty->print_cr(" fine pass: SO length " SIZE_FORMAT ", setting it to " SIZE_FORMAT, final_so_length, new_so_length); #endif // TRACE_CALC_YOUNG_CONFIG from_so_length = new_so_length; to_so_length = new_so_length; fine_so_length = final_so_length; pass = pass_type_final; } } } else if (pass == pass_type_final) { // we just finished the final (third) pass if (!gc_eff_set) // we didn't find a feasible config, so we'll just use the one // we found during the second pass, which we saved final_so_length = fine_so_length; // and we're done! done = true; } else { guarantee( false, "should never reach here" ); } // we now go around the outermost loop } // we should have at least one region in the target young length _young_list_target_length = MAX2((size_t) 1, final_young_length + _recorded_survivor_regions); if (final_so_length >= final_young_length) // and we need to ensure that the S-O length is not greater than // the target young length (this is being a bit careful) final_so_length = 0; _young_list_so_prefix_length = final_so_length; guarantee( !_in_marking_window || !_last_full_young_gc || _young_list_so_prefix_length == 0, "invariant" ); // let's keep an eye of how long we spend on this calculation // right now, I assume that we'll print it when we need it; we // should really adde it to the breakdown of a pause double end_time_sec = os::elapsedTime(); double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0; #ifdef TRACE_CALC_YOUNG_CONFIG // leave this in for debugging, just in case gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT ", SO = " SIZE_FORMAT ", " "elapsed %1.2lf ms, calcs: " SIZE_FORMAT " (%s%s) " SIZE_FORMAT SIZE_FORMAT, target_pause_time_ms, _young_list_target_length - _young_list_so_prefix_length, _young_list_so_prefix_length, elapsed_time_ms, calculations, full_young_gcs() ? "full" : "partial", should_initiate_conc_mark() ? " i-m" : "", _in_marking_window, _in_marking_window_im); #endif // TRACE_CALC_YOUNG_CONFIG if (_young_list_target_length < _young_list_min_length) { // bummer; this means that, if we do a pause when the optimal // config dictates, we'll violate the pause spacing target (the // min length was calculate based on the application's current // alloc rate); // so, we have to bite the bullet, and allocate the minimum // number. We'll violate our target, but we just can't meet it. size_t so_length = 0; // a note further up explains why we do not want an S-O length // during marking if (!_in_marking_window && !_last_full_young_gc) // but we can still try to see whether we can find an optimal // S-O length so_length = calculate_optimal_so_length(_young_list_min_length); #ifdef TRACE_CALC_YOUNG_CONFIG // leave this in for debugging, just in case gclog_or_tty->print_cr("adjusted target length from " SIZE_FORMAT " to " SIZE_FORMAT ", SO " SIZE_FORMAT, _young_list_target_length, _young_list_min_length, so_length); #endif // TRACE_CALC_YOUNG_CONFIG _young_list_target_length = MAX2(_young_list_min_length, (size_t)1); _young_list_so_prefix_length = so_length; } } else { // we are in a partially-young mode or we've run out of regions (due // to evacuation failure) #ifdef TRACE_CALC_YOUNG_CONFIG // leave this in for debugging, just in case gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT ", SO " SIZE_FORMAT, _young_list_min_length, 0); #endif // TRACE_CALC_YOUNG_CONFIG // we'll do the pause as soon as possible and with no S-O prefix // (see above for the reasons behind the latter) _young_list_target_length = MAX2(_young_list_min_length, (size_t) 1); _young_list_so_prefix_length = 0; } _rs_lengths_prediction = rs_lengths; } // This is used by: calculate_optimal_so_length(length). It returns // the GC eff and predicted pause time for a particular config void G1CollectorPolicy::predict_gc_eff(size_t young_length, size_t so_length, double base_time_ms, double* ret_gc_eff, double* ret_pause_time_ms) { double so_time_ms = predict_scan_only_time_ms(so_length); double accum_surv_rate_adj = 0.0; if (so_length > 0) accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1)); double accum_surv_rate = accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj; size_t bytes_to_copy = (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes); double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy); double young_other_time_ms = predict_young_other_time_ms(young_length - so_length); double pause_time_ms = base_time_ms + so_time_ms + copy_time_ms + young_other_time_ms; size_t reclaimed_bytes = (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy; double gc_eff = (double) reclaimed_bytes / pause_time_ms; *ret_gc_eff = gc_eff; *ret_pause_time_ms = pause_time_ms; } // This is used by: calculate_young_list_target_config(rs_length). It // returns the GC eff of a particular config. It returns false if that // config violates any of the end conditions of the search in the // calling method, or true upon success. The end conditions were put // here since it's called twice and it was best not to replicate them // in the caller. Also, passing the parameteres avoids having to // recalculate them in the innermost loop. bool G1CollectorPolicy::predict_gc_eff(size_t young_length, size_t so_length, double base_time_with_so_ms, size_t init_free_regions, double target_pause_time_ms, double* ret_gc_eff) { *ret_gc_eff = 0.0; if (young_length >= init_free_regions) // end condition 1: not enough space for the young regions return false; double accum_surv_rate_adj = 0.0; if (so_length > 0) accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1)); double accum_surv_rate = accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj; size_t bytes_to_copy = (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes); double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy); double young_other_time_ms = predict_young_other_time_ms(young_length - so_length); double pause_time_ms = base_time_with_so_ms + copy_time_ms + young_other_time_ms; if (pause_time_ms > target_pause_time_ms) // end condition 2: over the target pause time return false; size_t reclaimed_bytes = (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy; size_t free_bytes = (init_free_regions - young_length) * HeapRegion::GrainBytes; if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes) // end condition 3: out of to-space (conservatively) return false; // success! double gc_eff = (double) reclaimed_bytes / pause_time_ms; *ret_gc_eff = gc_eff; return true; } double G1CollectorPolicy::predict_survivor_regions_evac_time() { double survivor_regions_evac_time = 0.0; for (HeapRegion * r = _recorded_survivor_head; r != NULL && r != _recorded_survivor_tail->get_next_young_region(); r = r->get_next_young_region()) { survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true); } return survivor_regions_evac_time; } void G1CollectorPolicy::check_prediction_validity() { guarantee( adaptive_young_list_length(), "should not call this otherwise" ); size_t rs_lengths = _g1->young_list_sampled_rs_lengths(); if (rs_lengths > _rs_lengths_prediction) { // add 10% to avoid having to recalculate often size_t rs_lengths_prediction = rs_lengths * 1100 / 1000; calculate_young_list_target_config(rs_lengths_prediction); } } HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size, bool is_tlab, bool* gc_overhead_limit_was_exceeded) { guarantee(false, "Not using this policy feature yet."); return NULL; } // This method controls how a collector handles one or more // of its generations being fully allocated. HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size, bool is_tlab) { guarantee(false, "Not using this policy feature yet."); return NULL; } #ifndef PRODUCT bool G1CollectorPolicy::verify_young_ages() { HeapRegion* head = _g1->young_list_first_region(); return verify_young_ages(head, _short_lived_surv_rate_group); // also call verify_young_ages on any additional surv rate groups } bool G1CollectorPolicy::verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group) { guarantee( surv_rate_group != NULL, "pre-condition" ); const char* name = surv_rate_group->name(); bool ret = true; int prev_age = -1; for (HeapRegion* curr = head; curr != NULL; curr = curr->get_next_young_region()) { SurvRateGroup* group = curr->surv_rate_group(); if (group == NULL && !curr->is_survivor()) { gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name); ret = false; } if (surv_rate_group == group) { int age = curr->age_in_surv_rate_group(); if (age < 0) { gclog_or_tty->print_cr("## %s: encountered negative age", name); ret = false; } if (age <= prev_age) { gclog_or_tty->print_cr("## %s: region ages are not strictly increasing " "(%d, %d)", name, age, prev_age); ret = false; } prev_age = age; } } return ret; } #endif // PRODUCT void G1CollectorPolicy::record_full_collection_start() { _cur_collection_start_sec = os::elapsedTime(); // Release the future to-space so that it is available for compaction into. _g1->set_full_collection(); } void G1CollectorPolicy::record_full_collection_end() { // Consider this like a collection pause for the purposes of allocation // since last pause. double end_sec = os::elapsedTime(); double full_gc_time_sec = end_sec - _cur_collection_start_sec; double full_gc_time_ms = full_gc_time_sec * 1000.0; checkpoint_conc_overhead(); _all_full_gc_times_ms->add(full_gc_time_ms); update_recent_gc_times(end_sec, full_gc_time_sec); _g1->clear_full_collection(); // "Nuke" the heuristics that control the fully/partially young GC // transitions and make sure we start with fully young GCs after the // Full GC. set_full_young_gcs(true); _last_full_young_gc = false; _should_revert_to_full_young_gcs = false; _should_initiate_conc_mark = false; _known_garbage_bytes = 0; _known_garbage_ratio = 0.0; _in_marking_window = false; _in_marking_window_im = false; _short_lived_surv_rate_group->record_scan_only_prefix(0); _short_lived_surv_rate_group->start_adding_regions(); // also call this on any additional surv rate groups record_survivor_regions(0, NULL, NULL); _prev_region_num_young = _region_num_young; _prev_region_num_tenured = _region_num_tenured; _free_regions_at_end_of_collection = _g1->free_regions(); _scan_only_regions_at_end_of_collection = 0; // Reset survivors SurvRateGroup. _survivor_surv_rate_group->reset(); calculate_young_list_min_length(); calculate_young_list_target_config(); } void G1CollectorPolicy::record_pop_compute_rc_start() { _pop_compute_rc_start = os::elapsedTime(); } void G1CollectorPolicy::record_pop_compute_rc_end() { double ms = (os::elapsedTime() - _pop_compute_rc_start)*1000.0; _cur_popular_compute_rc_time_ms = ms; _pop_compute_rc_start = 0.0; } void G1CollectorPolicy::record_pop_evac_start() { _pop_evac_start = os::elapsedTime(); } void G1CollectorPolicy::record_pop_evac_end() { double ms = (os::elapsedTime() - _pop_evac_start)*1000.0; _cur_popular_evac_time_ms = ms; _pop_evac_start = 0.0; } void G1CollectorPolicy::record_before_bytes(size_t bytes) { _bytes_in_to_space_before_gc += bytes; } void G1CollectorPolicy::record_after_bytes(size_t bytes) { _bytes_in_to_space_after_gc += bytes; } void G1CollectorPolicy::record_stop_world_start() { _stop_world_start = os::elapsedTime(); } void G1CollectorPolicy::record_collection_pause_start(double start_time_sec, size_t start_used) { if (PrintGCDetails) { gclog_or_tty->stamp(PrintGCTimeStamps); gclog_or_tty->print("[GC pause"); if (in_young_gc_mode()) gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial"); } assert(_g1->used_regions() == _g1->recalculate_used_regions(), "sanity"); double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0; _all_stop_world_times_ms->add(s_w_t_ms); _stop_world_start = 0.0; _cur_collection_start_sec = start_time_sec; _cur_collection_pause_used_at_start_bytes = start_used; _cur_collection_pause_used_regions_at_start = _g1->used_regions(); _pending_cards = _g1->pending_card_num(); _max_pending_cards = _g1->max_pending_card_num(); _bytes_in_to_space_before_gc = 0; _bytes_in_to_space_after_gc = 0; _bytes_in_collection_set_before_gc = 0; #ifdef DEBUG // initialise these to something well known so that we can spot // if they are not set properly for (int i = 0; i < _parallel_gc_threads; ++i) { _par_last_ext_root_scan_times_ms[i] = -666.0; _par_last_mark_stack_scan_times_ms[i] = -666.0; _par_last_scan_only_times_ms[i] = -666.0; _par_last_scan_only_regions_scanned[i] = -666.0; _par_last_update_rs_start_times_ms[i] = -666.0; _par_last_update_rs_times_ms[i] = -666.0; _par_last_update_rs_processed_buffers[i] = -666.0; _par_last_scan_rs_start_times_ms[i] = -666.0; _par_last_scan_rs_times_ms[i] = -666.0; _par_last_scan_new_refs_times_ms[i] = -666.0; _par_last_obj_copy_times_ms[i] = -666.0; _par_last_termination_times_ms[i] = -666.0; _pop_par_last_update_rs_start_times_ms[i] = -666.0; _pop_par_last_update_rs_times_ms[i] = -666.0; _pop_par_last_update_rs_processed_buffers[i] = -666.0; _pop_par_last_scan_rs_start_times_ms[i] = -666.0; _pop_par_last_scan_rs_times_ms[i] = -666.0; _pop_par_last_closure_app_times_ms[i] = -666.0; } #endif for (int i = 0; i < _aux_num; ++i) { _cur_aux_times_ms[i] = 0.0; _cur_aux_times_set[i] = false; } _satb_drain_time_set = false; _last_satb_drain_processed_buffers = -1; if (in_young_gc_mode()) _last_young_gc_full = false; // do that for any other surv rate groups _short_lived_surv_rate_group->stop_adding_regions(); size_t short_lived_so_length = _young_list_so_prefix_length; _short_lived_surv_rate_group->record_scan_only_prefix(short_lived_so_length); tag_scan_only(short_lived_so_length); if (G1UseSurvivorSpace) { _survivors_age_table.clear(); } assert( verify_young_ages(), "region age verification" ); } void G1CollectorPolicy::tag_scan_only(size_t short_lived_scan_only_length) { // done in a way that it can be extended for other surv rate groups too... HeapRegion* head = _g1->young_list_first_region(); bool finished_short_lived = (short_lived_scan_only_length == 0); if (finished_short_lived) return; for (HeapRegion* curr = head; curr != NULL; curr = curr->get_next_young_region()) { SurvRateGroup* surv_rate_group = curr->surv_rate_group(); int age = curr->age_in_surv_rate_group(); if (surv_rate_group == _short_lived_surv_rate_group) { if ((size_t)age < short_lived_scan_only_length) curr->set_scan_only(); else finished_short_lived = true; } if (finished_short_lived) return; } guarantee( false, "we should never reach here" ); } void G1CollectorPolicy::record_popular_pause_preamble_start() { _cur_popular_preamble_start_ms = os::elapsedTime() * 1000.0; } void G1CollectorPolicy::record_popular_pause_preamble_end() { _cur_popular_preamble_time_ms = (os::elapsedTime() * 1000.0) - _cur_popular_preamble_start_ms; // copy the recorded statistics of the first pass to temporary arrays for (int i = 0; i < _parallel_gc_threads; ++i) { _pop_par_last_update_rs_start_times_ms[i] = _par_last_update_rs_start_times_ms[i]; _pop_par_last_update_rs_times_ms[i] = _par_last_update_rs_times_ms[i]; _pop_par_last_update_rs_processed_buffers[i] = _par_last_update_rs_processed_buffers[i]; _pop_par_last_scan_rs_start_times_ms[i] = _par_last_scan_rs_start_times_ms[i]; _pop_par_last_scan_rs_times_ms[i] = _par_last_scan_rs_times_ms[i]; _pop_par_last_closure_app_times_ms[i] = _par_last_obj_copy_times_ms[i]; } } void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) { _mark_closure_time_ms = mark_closure_time_ms; } void G1CollectorPolicy::record_concurrent_mark_init_start() { _mark_init_start_sec = os::elapsedTime(); guarantee(!in_young_gc_mode(), "should not do be here in young GC mode"); } void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double mark_init_elapsed_time_ms) { _during_marking = true; _should_initiate_conc_mark = false; _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms; } void G1CollectorPolicy::record_concurrent_mark_init_end() { double end_time_sec = os::elapsedTime(); double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0; _concurrent_mark_init_times_ms->add(elapsed_time_ms); checkpoint_conc_overhead(); record_concurrent_mark_init_end_pre(elapsed_time_ms); _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true); } void G1CollectorPolicy::record_concurrent_mark_remark_start() { _mark_remark_start_sec = os::elapsedTime(); _during_marking = false; } void G1CollectorPolicy::record_concurrent_mark_remark_end() { double end_time_sec = os::elapsedTime(); double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0; checkpoint_conc_overhead(); _concurrent_mark_remark_times_ms->add(elapsed_time_ms); _cur_mark_stop_world_time_ms += elapsed_time_ms; _prev_collection_pause_end_ms += elapsed_time_ms; _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true); } void G1CollectorPolicy::record_concurrent_mark_cleanup_start() { _mark_cleanup_start_sec = os::elapsedTime(); } void G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes, size_t max_live_bytes) { record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes); record_concurrent_mark_cleanup_end_work2(); } void G1CollectorPolicy:: record_concurrent_mark_cleanup_end_work1(size_t freed_bytes, size_t max_live_bytes) { if (_n_marks < 2) _n_marks++; if (G1PolicyVerbose > 0) gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB " " (of " SIZE_FORMAT " MB heap).", max_live_bytes/M, _g1->capacity()/M); } // The important thing about this is that it includes "os::elapsedTime". void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() { checkpoint_conc_overhead(); double end_time_sec = os::elapsedTime(); double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0; _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms); _cur_mark_stop_world_time_ms += elapsed_time_ms; _prev_collection_pause_end_ms += elapsed_time_ms; _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true); _num_markings++; // We did a marking, so reset the "since_last_mark" variables. double considerConcMarkCost = 1.0; // If there are available processors, concurrent activity is free... if (Threads::number_of_non_daemon_threads() * 2 < os::active_processor_count()) { considerConcMarkCost = 0.0; } _n_pauses_at_mark_end = _n_pauses; _n_marks_since_last_pause++; _conc_mark_initiated = false; } void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() { if (in_young_gc_mode()) { _should_revert_to_full_young_gcs = false; _last_full_young_gc = true; _in_marking_window = false; if (adaptive_young_list_length()) calculate_young_list_target_config(); } } void G1CollectorPolicy::record_concurrent_pause() { if (_stop_world_start > 0.0) { double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0; _all_yield_times_ms->add(yield_ms); } } void G1CollectorPolicy::record_concurrent_pause_end() { } void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() { _cur_CH_strong_roots_end_sec = os::elapsedTime(); _cur_CH_strong_roots_dur_ms = (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0; } void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() { _cur_G1_strong_roots_end_sec = os::elapsedTime(); _cur_G1_strong_roots_dur_ms = (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0; } template<class T> T sum_of(T* sum_arr, int start, int n, int N) { T sum = (T)0; for (int i = 0; i < n; i++) { int j = (start + i) % N; sum += sum_arr[j]; } return sum; } void G1CollectorPolicy::print_par_stats (int level, const char* str, double* data, bool summary) { double min = data[0], max = data[0]; double total = 0.0; int j; for (j = 0; j < level; ++j) gclog_or_tty->print(" "); gclog_or_tty->print("[%s (ms):", str); for (uint i = 0; i < ParallelGCThreads; ++i) { double val = data[i]; if (val < min) min = val; if (val > max) max = val; total += val; gclog_or_tty->print(" %3.1lf", val); } if (summary) { gclog_or_tty->print_cr(""); double avg = total / (double) ParallelGCThreads; gclog_or_tty->print(" "); for (j = 0; j < level; ++j) gclog_or_tty->print(" "); gclog_or_tty->print("Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf", avg, min, max); } gclog_or_tty->print_cr("]"); } void G1CollectorPolicy::print_par_buffers (int level, const char* str, double* data, bool summary) { double min = data[0], max = data[0]; double total = 0.0; int j; for (j = 0; j < level; ++j) gclog_or_tty->print(" "); gclog_or_tty->print("[%s :", str); for (uint i = 0; i < ParallelGCThreads; ++i) { double val = data[i]; if (val < min) min = val; if (val > max) max = val; total += val; gclog_or_tty->print(" %d", (int) val); } if (summary) { gclog_or_tty->print_cr(""); double avg = total / (double) ParallelGCThreads; gclog_or_tty->print(" "); for (j = 0; j < level; ++j) gclog_or_tty->print(" "); gclog_or_tty->print("Sum: %d, Avg: %d, Min: %d, Max: %d", (int)total, (int)avg, (int)min, (int)max); } gclog_or_tty->print_cr("]"); } void G1CollectorPolicy::print_stats (int level, const char* str, double value) { for (int j = 0; j < level; ++j) gclog_or_tty->print(" "); gclog_or_tty->print_cr("[%s: %5.1lf ms]", str, value); } void G1CollectorPolicy::print_stats (int level, const char* str, int value) { for (int j = 0; j < level; ++j) gclog_or_tty->print(" "); gclog_or_tty->print_cr("[%s: %d]", str, value); } double G1CollectorPolicy::avg_value (double* data) { if (ParallelGCThreads > 0) { double ret = 0.0; for (uint i = 0; i < ParallelGCThreads; ++i) ret += data[i]; return ret / (double) ParallelGCThreads; } else { return data[0]; } } double G1CollectorPolicy::max_value (double* data) { if (ParallelGCThreads > 0) { double ret = data[0]; for (uint i = 1; i < ParallelGCThreads; ++i) if (data[i] > ret) ret = data[i]; return ret; } else { return data[0]; } } double G1CollectorPolicy::sum_of_values (double* data) { if (ParallelGCThreads > 0) { double sum = 0.0; for (uint i = 0; i < ParallelGCThreads; i++) sum += data[i]; return sum; } else { return data[0]; } } double G1CollectorPolicy::max_sum (double* data1, double* data2) { double ret = data1[0] + data2[0]; if (ParallelGCThreads > 0) { for (uint i = 1; i < ParallelGCThreads; ++i) { double data = data1[i] + data2[i]; if (data > ret) ret = data; } } return ret; } // Anything below that is considered to be zero #define MIN_TIMER_GRANULARITY 0.0000001 void G1CollectorPolicy::record_collection_pause_end(bool popular, bool abandoned) { double end_time_sec = os::elapsedTime(); double elapsed_ms = _last_pause_time_ms; bool parallel = ParallelGCThreads > 0; double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0; size_t rs_size = _cur_collection_pause_used_regions_at_start - collection_set_size(); size_t cur_used_bytes = _g1->used(); assert(cur_used_bytes == _g1->recalculate_used(), "It should!"); bool last_pause_included_initial_mark = false; #ifndef PRODUCT if (G1YoungSurvRateVerbose) { gclog_or_tty->print_cr(""); _short_lived_surv_rate_group->print(); // do that for any other surv rate groups too } #endif // PRODUCT checkpoint_conc_overhead(); if (in_young_gc_mode()) { last_pause_included_initial_mark = _should_initiate_conc_mark; if (last_pause_included_initial_mark) record_concurrent_mark_init_end_pre(0.0); size_t min_used_targ = (_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta); if (cur_used_bytes > min_used_targ) { if (cur_used_bytes <= _prev_collection_pause_used_at_end_bytes) { } else if (!_g1->mark_in_progress() && !_last_full_young_gc) { _should_initiate_conc_mark = true; } } _prev_collection_pause_used_at_end_bytes = cur_used_bytes; } _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0, end_time_sec, false); guarantee(_cur_collection_pause_used_regions_at_start >= collection_set_size(), "Negative RS size?"); // This assert is exempted when we're doing parallel collection pauses, // because the fragmentation caused by the parallel GC allocation buffers // can lead to more memory being used during collection than was used // before. Best leave this out until the fragmentation problem is fixed. // Pauses in which evacuation failed can also lead to negative // collections, since no space is reclaimed from a region containing an // object whose evacuation failed. // Further, we're now always doing parallel collection. But I'm still // leaving this here as a placeholder for a more precise assertion later. // (DLD, 10/05.) assert((true || parallel) // Always using GC LABs now. || _g1->evacuation_failed() || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes, "Negative collection"); size_t freed_bytes = _cur_collection_pause_used_at_start_bytes - cur_used_bytes; size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes; double survival_fraction = (double)surviving_bytes/ (double)_collection_set_bytes_used_before; _n_pauses++; if (!abandoned) { _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms); _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms); _recent_evac_times_ms->add(evac_ms); _recent_pause_times_ms->add(elapsed_ms); _recent_rs_sizes->add(rs_size); // We exempt parallel collection from this check because Alloc Buffer // fragmentation can produce negative collections. Same with evac // failure. // Further, we're now always doing parallel collection. But I'm still // leaving this here as a placeholder for a more precise assertion later. // (DLD, 10/05. assert((true || parallel) || _g1->evacuation_failed() || surviving_bytes <= _collection_set_bytes_used_before, "Or else negative collection!"); _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before); _recent_CS_bytes_surviving->add(surviving_bytes); // this is where we update the allocation rate of the application double app_time_ms = (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms); if (app_time_ms < MIN_TIMER_GRANULARITY) { // This usually happens due to the timer not having the required // granularity. Some Linuxes are the usual culprits. // We'll just set it to something (arbitrarily) small. app_time_ms = 1.0; } size_t regions_allocated = (_region_num_young - _prev_region_num_young) + (_region_num_tenured - _prev_region_num_tenured); double alloc_rate_ms = (double) regions_allocated / app_time_ms; _alloc_rate_ms_seq->add(alloc_rate_ms); _prev_region_num_young = _region_num_young; _prev_region_num_tenured = _region_num_tenured; double interval_ms = (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0; update_recent_gc_times(end_time_sec, elapsed_ms); _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms; assert(recent_avg_pause_time_ratio() < 1.00, "All GC?"); } if (G1PolicyVerbose > 1) { gclog_or_tty->print_cr(" Recording collection pause(%d)", _n_pauses); } PauseSummary* summary; if (!abandoned && !popular) summary = _non_pop_summary; else if (!abandoned && popular) summary = _pop_summary; else if (abandoned && !popular) summary = _non_pop_abandoned_summary; else if (abandoned && popular) summary = _pop_abandoned_summary; else guarantee(false, "should not get here!"); double pop_update_rs_time; double pop_update_rs_processed_buffers; double pop_scan_rs_time; double pop_closure_app_time; double pop_other_time; if (popular) { PopPreambleSummary* preamble_summary = summary->pop_preamble_summary(); guarantee(preamble_summary != NULL, "should not be null!"); pop_update_rs_time = avg_value(_pop_par_last_update_rs_times_ms); pop_update_rs_processed_buffers = sum_of_values(_pop_par_last_update_rs_processed_buffers); pop_scan_rs_time = avg_value(_pop_par_last_scan_rs_times_ms); pop_closure_app_time = avg_value(_pop_par_last_closure_app_times_ms); pop_other_time = _cur_popular_preamble_time_ms - (pop_update_rs_time + pop_scan_rs_time + pop_closure_app_time + _cur_popular_evac_time_ms); preamble_summary->record_pop_preamble_time_ms(_cur_popular_preamble_time_ms); preamble_summary->record_pop_update_rs_time_ms(pop_update_rs_time); preamble_summary->record_pop_scan_rs_time_ms(pop_scan_rs_time); preamble_summary->record_pop_closure_app_time_ms(pop_closure_app_time); preamble_summary->record_pop_evacuation_time_ms(_cur_popular_evac_time_ms); preamble_summary->record_pop_other_time_ms(pop_other_time); } double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms); double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms); double scan_only_time = avg_value(_par_last_scan_only_times_ms); double scan_only_regions_scanned = sum_of_values(_par_last_scan_only_regions_scanned); double update_rs_time = avg_value(_par_last_update_rs_times_ms); double update_rs_processed_buffers = sum_of_values(_par_last_update_rs_processed_buffers); double scan_rs_time = avg_value(_par_last_scan_rs_times_ms); double obj_copy_time = avg_value(_par_last_obj_copy_times_ms); double termination_time = avg_value(_par_last_termination_times_ms); double parallel_other_time; if (!abandoned) { MainBodySummary* body_summary = summary->main_body_summary(); guarantee(body_summary != NULL, "should not be null!"); if (_satb_drain_time_set) body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms); else body_summary->record_satb_drain_time_ms(0.0); body_summary->record_ext_root_scan_time_ms(ext_root_scan_time); body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time); body_summary->record_scan_only_time_ms(scan_only_time); body_summary->record_update_rs_time_ms(update_rs_time); body_summary->record_scan_rs_time_ms(scan_rs_time); body_summary->record_obj_copy_time_ms(obj_copy_time); if (parallel) { body_summary->record_parallel_time_ms(_cur_collection_par_time_ms); body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms); body_summary->record_termination_time_ms(termination_time); parallel_other_time = _cur_collection_par_time_ms - (update_rs_time + ext_root_scan_time + mark_stack_scan_time + scan_only_time + scan_rs_time + obj_copy_time + termination_time); body_summary->record_parallel_other_time_ms(parallel_other_time); } body_summary->record_mark_closure_time_ms(_mark_closure_time_ms); } if (G1PolicyVerbose > 1) { gclog_or_tty->print_cr(" ET: %10.6f ms (avg: %10.6f ms)\n" " CH Strong: %10.6f ms (avg: %10.6f ms)\n" " G1 Strong: %10.6f ms (avg: %10.6f ms)\n" " Evac: %10.6f ms (avg: %10.6f ms)\n" " ET-RS: %10.6f ms (avg: %10.6f ms)\n" " |RS|: " SIZE_FORMAT, elapsed_ms, recent_avg_time_for_pauses_ms(), _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(), _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(), evac_ms, recent_avg_time_for_evac_ms(), scan_rs_time, recent_avg_time_for_pauses_ms() - recent_avg_time_for_G1_strong_ms(), rs_size); gclog_or_tty->print_cr(" Used at start: " SIZE_FORMAT"K" " At end " SIZE_FORMAT "K\n" " garbage : " SIZE_FORMAT "K" " of " SIZE_FORMAT "K\n" " survival : %6.2f%% (%6.2f%% avg)", _cur_collection_pause_used_at_start_bytes/K, _g1->used()/K, freed_bytes/K, _collection_set_bytes_used_before/K, survival_fraction*100.0, recent_avg_survival_fraction()*100.0); gclog_or_tty->print_cr(" Recent %% gc pause time: %6.2f", recent_avg_pause_time_ratio() * 100.0); } double other_time_ms = elapsed_ms; if (popular) other_time_ms -= _cur_popular_preamble_time_ms; if (!abandoned) { if (_satb_drain_time_set) other_time_ms -= _cur_satb_drain_time_ms; if (parallel) other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms; else other_time_ms -= update_rs_time + ext_root_scan_time + mark_stack_scan_time + scan_only_time + scan_rs_time + obj_copy_time; } if (PrintGCDetails) { gclog_or_tty->print_cr("%s%s, %1.8lf secs]", (popular && !abandoned) ? " (popular)" : (!popular && abandoned) ? " (abandoned)" : (popular && abandoned) ? " (popular/abandoned)" : "", (last_pause_included_initial_mark) ? " (initial-mark)" : "", elapsed_ms / 1000.0); if (!abandoned) { if (_satb_drain_time_set) print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms); if (_last_satb_drain_processed_buffers >= 0) print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers); } if (popular) print_stats(1, "Popularity Preamble", _cur_popular_preamble_time_ms); if (parallel) { if (popular) { print_par_stats(2, "Update RS (Start)", _pop_par_last_update_rs_start_times_ms, false); print_par_stats(2, "Update RS", _pop_par_last_update_rs_times_ms); if (G1RSBarrierUseQueue) print_par_buffers(3, "Processed Buffers", _pop_par_last_update_rs_processed_buffers, true); print_par_stats(2, "Scan RS", _pop_par_last_scan_rs_times_ms); print_par_stats(2, "Closure app", _pop_par_last_closure_app_times_ms); print_stats(2, "Evacuation", _cur_popular_evac_time_ms); print_stats(2, "Other", pop_other_time); } if (!abandoned) { print_stats(1, "Parallel Time", _cur_collection_par_time_ms); if (!popular) { print_par_stats(2, "Update RS (Start)", _par_last_update_rs_start_times_ms, false); print_par_stats(2, "Update RS", _par_last_update_rs_times_ms); if (G1RSBarrierUseQueue) print_par_buffers(3, "Processed Buffers", _par_last_update_rs_processed_buffers, true); } print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms); print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms); print_par_stats(2, "Scan-Only Scanning", _par_last_scan_only_times_ms); print_par_buffers(3, "Scan-Only Regions", _par_last_scan_only_regions_scanned, true); print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms); print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms); print_par_stats(2, "Termination", _par_last_termination_times_ms); print_stats(2, "Other", parallel_other_time); print_stats(1, "Clear CT", _cur_clear_ct_time_ms); } } else { if (popular) { print_stats(2, "Update RS", pop_update_rs_time); if (G1RSBarrierUseQueue) print_stats(3, "Processed Buffers", (int)pop_update_rs_processed_buffers); print_stats(2, "Scan RS", pop_scan_rs_time); print_stats(2, "Closure App", pop_closure_app_time); print_stats(2, "Evacuation", _cur_popular_evac_time_ms); print_stats(2, "Other", pop_other_time); } if (!abandoned) { if (!popular) { print_stats(1, "Update RS", update_rs_time); if (G1RSBarrierUseQueue) print_stats(2, "Processed Buffers", (int)update_rs_processed_buffers); } print_stats(1, "Ext Root Scanning", ext_root_scan_time); print_stats(1, "Mark Stack Scanning", mark_stack_scan_time); print_stats(1, "Scan-Only Scanning", scan_only_time); print_stats(1, "Scan RS", scan_rs_time); print_stats(1, "Object Copying", obj_copy_time); } } print_stats(1, "Other", other_time_ms); for (int i = 0; i < _aux_num; ++i) { if (_cur_aux_times_set[i]) { char buffer[96]; sprintf(buffer, "Aux%d", i); print_stats(1, buffer, _cur_aux_times_ms[i]); } } } if (PrintGCDetails) gclog_or_tty->print(" ["); if (PrintGC || PrintGCDetails) _g1->print_size_transition(gclog_or_tty, _cur_collection_pause_used_at_start_bytes, _g1->used(), _g1->capacity()); if (PrintGCDetails) gclog_or_tty->print_cr("]"); _all_pause_times_ms->add(elapsed_ms); summary->record_total_time_ms(elapsed_ms); summary->record_other_time_ms(other_time_ms); for (int i = 0; i < _aux_num; ++i) if (_cur_aux_times_set[i]) _all_aux_times_ms[i].add(_cur_aux_times_ms[i]); // Reset marks-between-pauses counter. _n_marks_since_last_pause = 0; // Update the efficiency-since-mark vars. double proc_ms = elapsed_ms * (double) _parallel_gc_threads; if (elapsed_ms < MIN_TIMER_GRANULARITY) { // This usually happens due to the timer not having the required // granularity. Some Linuxes are the usual culprits. // We'll just set it to something (arbitrarily) small. proc_ms = 1.0; } double cur_efficiency = (double) freed_bytes / proc_ms; bool new_in_marking_window = _in_marking_window; bool new_in_marking_window_im = false; if (_should_initiate_conc_mark) { new_in_marking_window = true; new_in_marking_window_im = true; } if (in_young_gc_mode()) { if (_last_full_young_gc) { set_full_young_gcs(false); _last_full_young_gc = false; } if ( !_last_young_gc_full ) { if ( _should_revert_to_full_young_gcs || _known_garbage_ratio < 0.05 || (adaptive_young_list_length() && (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) { set_full_young_gcs(true); } } _should_revert_to_full_young_gcs = false; if (_last_young_gc_full && !_during_marking) _young_gc_eff_seq->add(cur_efficiency); } _short_lived_surv_rate_group->start_adding_regions(); // do that for any other surv rate groupsx // <NEW PREDICTION> if (!popular && !abandoned) { double pause_time_ms = elapsed_ms; size_t diff = 0; if (_max_pending_cards >= _pending_cards) diff = _max_pending_cards - _pending_cards; _pending_card_diff_seq->add((double) diff); double cost_per_card_ms = 0.0; if (_pending_cards > 0) { cost_per_card_ms = update_rs_time / (double) _pending_cards; _cost_per_card_ms_seq->add(cost_per_card_ms); } double cost_per_scan_only_region_ms = 0.0; if (scan_only_regions_scanned > 0.0) { cost_per_scan_only_region_ms = scan_only_time / scan_only_regions_scanned; if (_in_marking_window_im) _cost_per_scan_only_region_ms_during_cm_seq->add(cost_per_scan_only_region_ms); else _cost_per_scan_only_region_ms_seq->add(cost_per_scan_only_region_ms); } size_t cards_scanned = _g1->cards_scanned(); double cost_per_entry_ms = 0.0; if (cards_scanned > 10) { cost_per_entry_ms = scan_rs_time / (double) cards_scanned; if (_last_young_gc_full) _cost_per_entry_ms_seq->add(cost_per_entry_ms); else _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms); } if (_max_rs_lengths > 0) { double cards_per_entry_ratio = (double) cards_scanned / (double) _max_rs_lengths; if (_last_young_gc_full) _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio); else _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio); } size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths; if (rs_length_diff >= 0) _rs_length_diff_seq->add((double) rs_length_diff); size_t copied_bytes = surviving_bytes; double cost_per_byte_ms = 0.0; if (copied_bytes > 0) { cost_per_byte_ms = obj_copy_time / (double) copied_bytes; if (_in_marking_window) _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms); else _cost_per_byte_ms_seq->add(cost_per_byte_ms); } double all_other_time_ms = pause_time_ms - (update_rs_time + scan_only_time + scan_rs_time + obj_copy_time + _mark_closure_time_ms + termination_time); double young_other_time_ms = 0.0; if (_recorded_young_regions > 0) { young_other_time_ms = _recorded_young_cset_choice_time_ms + _recorded_young_free_cset_time_ms; _young_other_cost_per_region_ms_seq->add(young_other_time_ms / (double) _recorded_young_regions); } double non_young_other_time_ms = 0.0; if (_recorded_non_young_regions > 0) { non_young_other_time_ms = _recorded_non_young_cset_choice_time_ms + _recorded_non_young_free_cset_time_ms; _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms / (double) _recorded_non_young_regions); } double constant_other_time_ms = all_other_time_ms - (young_other_time_ms + non_young_other_time_ms); _constant_other_time_ms_seq->add(constant_other_time_ms); double survival_ratio = 0.0; if (_bytes_in_collection_set_before_gc > 0) { survival_ratio = (double) bytes_in_to_space_during_gc() / (double) _bytes_in_collection_set_before_gc; } _pending_cards_seq->add((double) _pending_cards); _scanned_cards_seq->add((double) cards_scanned); _rs_lengths_seq->add((double) _max_rs_lengths); double expensive_region_limit_ms = (double) G1MaxPauseTimeMS - predict_constant_other_time_ms(); if (expensive_region_limit_ms < 0.0) { // this means that the other time was predicted to be longer than // than the max pause time expensive_region_limit_ms = (double) G1MaxPauseTimeMS; } _expensive_region_limit_ms = expensive_region_limit_ms; if (PREDICTIONS_VERBOSE) { gclog_or_tty->print_cr(""); gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d " "REGIONS %d %d %d %d " "PENDING_CARDS %d %d " "CARDS_SCANNED %d %d " "RS_LENGTHS %d %d " "SCAN_ONLY_SCAN %1.6lf %1.6lf " "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf " "SURVIVAL_RATIO %1.6lf %1.6lf " "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf " "OTHER_YOUNG %1.6lf %1.6lf " "OTHER_NON_YOUNG %1.6lf %1.6lf " "VTIME_DIFF %1.6lf TERMINATION %1.6lf " "ELAPSED %1.6lf %1.6lf ", _cur_collection_start_sec, (!_last_young_gc_full) ? 2 : (last_pause_included_initial_mark) ? 1 : 0, _recorded_region_num, _recorded_young_regions, _recorded_scan_only_regions, _recorded_non_young_regions, _predicted_pending_cards, _pending_cards, _predicted_cards_scanned, cards_scanned, _predicted_rs_lengths, _max_rs_lengths, _predicted_scan_only_scan_time_ms, scan_only_time, _predicted_rs_update_time_ms, update_rs_time, _predicted_rs_scan_time_ms, scan_rs_time, _predicted_survival_ratio, survival_ratio, _predicted_object_copy_time_ms, obj_copy_time, _predicted_constant_other_time_ms, constant_other_time_ms, _predicted_young_other_time_ms, young_other_time_ms, _predicted_non_young_other_time_ms, non_young_other_time_ms, _vtime_diff_ms, termination_time, _predicted_pause_time_ms, elapsed_ms); } if (G1PolicyVerbose > 0) { gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms", _predicted_pause_time_ms, (_within_target) ? "within" : "outside", elapsed_ms); } } _in_marking_window = new_in_marking_window; _in_marking_window_im = new_in_marking_window_im; _free_regions_at_end_of_collection = _g1->free_regions(); _scan_only_regions_at_end_of_collection = _g1->young_list_length(); calculate_young_list_min_length(); calculate_young_list_target_config(); // </NEW PREDICTION> _target_pause_time_ms = -1.0; } // <NEW PREDICTION> double G1CollectorPolicy:: predict_young_collection_elapsed_time_ms(size_t adjustment) { guarantee( adjustment == 0 || adjustment == 1, "invariant" ); G1CollectedHeap* g1h = G1CollectedHeap::heap(); size_t young_num = g1h->young_list_length(); if (young_num == 0) return 0.0; young_num += adjustment; size_t pending_cards = predict_pending_cards(); size_t rs_lengths = g1h->young_list_sampled_rs_lengths() + predict_rs_length_diff(); size_t card_num; if (full_young_gcs()) card_num = predict_young_card_num(rs_lengths); else card_num = predict_non_young_card_num(rs_lengths); size_t young_byte_size = young_num * HeapRegion::GrainBytes; double accum_yg_surv_rate = _short_lived_surv_rate_group->accum_surv_rate(adjustment); size_t bytes_to_copy = (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes); return predict_rs_update_time_ms(pending_cards) + predict_rs_scan_time_ms(card_num) + predict_object_copy_time_ms(bytes_to_copy) + predict_young_other_time_ms(young_num) + predict_constant_other_time_ms(); } double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) { size_t rs_length = predict_rs_length_diff(); size_t card_num; if (full_young_gcs()) card_num = predict_young_card_num(rs_length); else card_num = predict_non_young_card_num(rs_length); return predict_base_elapsed_time_ms(pending_cards, card_num); } double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards, size_t scanned_cards) { return predict_rs_update_time_ms(pending_cards) + predict_rs_scan_time_ms(scanned_cards) + predict_constant_other_time_ms(); } double G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr, bool young) { size_t rs_length = hr->rem_set()->occupied(); size_t card_num; if (full_young_gcs()) card_num = predict_young_card_num(rs_length); else card_num = predict_non_young_card_num(rs_length); size_t bytes_to_copy = predict_bytes_to_copy(hr); double region_elapsed_time_ms = predict_rs_scan_time_ms(card_num) + predict_object_copy_time_ms(bytes_to_copy); if (young) region_elapsed_time_ms += predict_young_other_time_ms(1); else region_elapsed_time_ms += predict_non_young_other_time_ms(1); return region_elapsed_time_ms; } size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) { size_t bytes_to_copy; if (hr->is_marked()) bytes_to_copy = hr->max_live_bytes(); else { guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant" ); int age = hr->age_in_surv_rate_group(); double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group()); bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate); } return bytes_to_copy; } void G1CollectorPolicy::start_recording_regions() { _recorded_rs_lengths = 0; _recorded_scan_only_regions = 0; _recorded_young_regions = 0; _recorded_non_young_regions = 0; #if PREDICTIONS_VERBOSE _predicted_rs_lengths = 0; _predicted_cards_scanned = 0; _recorded_marked_bytes = 0; _recorded_young_bytes = 0; _predicted_bytes_to_copy = 0; #endif // PREDICTIONS_VERBOSE } void G1CollectorPolicy::record_cset_region(HeapRegion* hr, bool young) { if (young) { ++_recorded_young_regions; } else { ++_recorded_non_young_regions; } #if PREDICTIONS_VERBOSE if (young) { _recorded_young_bytes += hr->used(); } else { _recorded_marked_bytes += hr->max_live_bytes(); } _predicted_bytes_to_copy += predict_bytes_to_copy(hr); #endif // PREDICTIONS_VERBOSE size_t rs_length = hr->rem_set()->occupied(); _recorded_rs_lengths += rs_length; } void G1CollectorPolicy::record_scan_only_regions(size_t scan_only_length) { _recorded_scan_only_regions = scan_only_length; } void G1CollectorPolicy::end_recording_regions() { #if PREDICTIONS_VERBOSE _predicted_pending_cards = predict_pending_cards(); _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff(); if (full_young_gcs()) _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths); else _predicted_cards_scanned += predict_non_young_card_num(_predicted_rs_lengths); _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions; _predicted_scan_only_scan_time_ms = predict_scan_only_time_ms(_recorded_scan_only_regions); _predicted_rs_update_time_ms = predict_rs_update_time_ms(_g1->pending_card_num()); _predicted_rs_scan_time_ms = predict_rs_scan_time_ms(_predicted_cards_scanned); _predicted_object_copy_time_ms = predict_object_copy_time_ms(_predicted_bytes_to_copy); _predicted_constant_other_time_ms = predict_constant_other_time_ms(); _predicted_young_other_time_ms = predict_young_other_time_ms(_recorded_young_regions); _predicted_non_young_other_time_ms = predict_non_young_other_time_ms(_recorded_non_young_regions); _predicted_pause_time_ms = _predicted_scan_only_scan_time_ms + _predicted_rs_update_time_ms + _predicted_rs_scan_time_ms + _predicted_object_copy_time_ms + _predicted_constant_other_time_ms + _predicted_young_other_time_ms + _predicted_non_young_other_time_ms; #endif // PREDICTIONS_VERBOSE } void G1CollectorPolicy::check_if_region_is_too_expensive(double predicted_time_ms) { // I don't think we need to do this when in young GC mode since // marking will be initiated next time we hit the soft limit anyway... if (predicted_time_ms > _expensive_region_limit_ms) { if (!in_young_gc_mode()) { set_full_young_gcs(true); _should_initiate_conc_mark = true; } else // no point in doing another partial one _should_revert_to_full_young_gcs = true; } } // </NEW PREDICTION> void G1CollectorPolicy::update_recent_gc_times(double end_time_sec, double elapsed_ms) { _recent_gc_times_ms->add(elapsed_ms); _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec); _prev_collection_pause_end_ms = end_time_sec * 1000.0; } double G1CollectorPolicy::recent_avg_time_for_pauses_ms() { if (_recent_pause_times_ms->num() == 0) return (double) G1MaxPauseTimeMS; else return _recent_pause_times_ms->avg(); } double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() { if (_recent_CH_strong_roots_times_ms->num() == 0) return (double)G1MaxPauseTimeMS/3.0; else return _recent_CH_strong_roots_times_ms->avg(); } double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() { if (_recent_G1_strong_roots_times_ms->num() == 0) return (double)G1MaxPauseTimeMS/3.0; else return _recent_G1_strong_roots_times_ms->avg(); } double G1CollectorPolicy::recent_avg_time_for_evac_ms() { if (_recent_evac_times_ms->num() == 0) return (double)G1MaxPauseTimeMS/3.0; else return _recent_evac_times_ms->avg(); } int G1CollectorPolicy::number_of_recent_gcs() { assert(_recent_CH_strong_roots_times_ms->num() == _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync"); assert(_recent_G1_strong_roots_times_ms->num() == _recent_evac_times_ms->num(), "Sequence out of sync"); assert(_recent_evac_times_ms->num() == _recent_pause_times_ms->num(), "Sequence out of sync"); assert(_recent_pause_times_ms->num() == _recent_CS_bytes_used_before->num(), "Sequence out of sync"); assert(_recent_CS_bytes_used_before->num() == _recent_CS_bytes_surviving->num(), "Sequence out of sync"); return _recent_pause_times_ms->num(); } double G1CollectorPolicy::recent_avg_survival_fraction() { return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving, _recent_CS_bytes_used_before); } double G1CollectorPolicy::last_survival_fraction() { return last_survival_fraction_work(_recent_CS_bytes_surviving, _recent_CS_bytes_used_before); } double G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving, TruncatedSeq* before) { assert(surviving->num() == before->num(), "Sequence out of sync"); if (before->sum() > 0.0) { double recent_survival_rate = surviving->sum() / before->sum(); // We exempt parallel collection from this check because Alloc Buffer // fragmentation can produce negative collections. // Further, we're now always doing parallel collection. But I'm still // leaving this here as a placeholder for a more precise assertion later. // (DLD, 10/05.) assert((true || ParallelGCThreads > 0) || _g1->evacuation_failed() || recent_survival_rate <= 1.0, "Or bad frac"); return recent_survival_rate; } else { return 1.0; // Be conservative. } } double G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving, TruncatedSeq* before) { assert(surviving->num() == before->num(), "Sequence out of sync"); if (surviving->num() > 0 && before->last() > 0.0) { double last_survival_rate = surviving->last() / before->last(); // We exempt parallel collection from this check because Alloc Buffer // fragmentation can produce negative collections. // Further, we're now always doing parallel collection. But I'm still // leaving this here as a placeholder for a more precise assertion later. // (DLD, 10/05.) assert((true || ParallelGCThreads > 0) || last_survival_rate <= 1.0, "Or bad frac"); return last_survival_rate; } else { return 1.0; } } static const int survival_min_obs = 5; static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 }; static const double min_survival_rate = 0.1; double G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg, double latest) { double res = avg; if (number_of_recent_gcs() < survival_min_obs) { res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]); } res = MAX2(res, latest); res = MAX2(res, min_survival_rate); // In the parallel case, LAB fragmentation can produce "negative // collections"; so can evac failure. Cap at 1.0 res = MIN2(res, 1.0); return res; } size_t G1CollectorPolicy::expansion_amount() { if ((int)(recent_avg_pause_time_ratio() * 100.0) > G1GCPct) { // We will double the existing space, or take G1ExpandByPctOfAvail % of // the available expansion space, whichever is smaller, bounded below // by a minimum expansion (unless that's all that's left.) const size_t min_expand_bytes = 1*M; size_t reserved_bytes = _g1->g1_reserved_obj_bytes(); size_t committed_bytes = _g1->capacity(); size_t uncommitted_bytes = reserved_bytes - committed_bytes; size_t expand_bytes; size_t expand_bytes_via_pct = uncommitted_bytes * G1ExpandByPctOfAvail / 100; expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes); expand_bytes = MAX2(expand_bytes, min_expand_bytes); expand_bytes = MIN2(expand_bytes, uncommitted_bytes); if (G1PolicyVerbose > 1) { gclog_or_tty->print("Decided to expand: ratio = %5.2f, " "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n" " Answer = %d.\n", recent_avg_pause_time_ratio(), byte_size_in_proper_unit(committed_bytes), proper_unit_for_byte_size(committed_bytes), byte_size_in_proper_unit(uncommitted_bytes), proper_unit_for_byte_size(uncommitted_bytes), byte_size_in_proper_unit(expand_bytes_via_pct), proper_unit_for_byte_size(expand_bytes_via_pct), byte_size_in_proper_unit(expand_bytes), proper_unit_for_byte_size(expand_bytes)); } return expand_bytes; } else { return 0; } } void G1CollectorPolicy::note_start_of_mark_thread() { _mark_thread_startup_sec = os::elapsedTime(); } class CountCSClosure: public HeapRegionClosure { G1CollectorPolicy* _g1_policy; public: CountCSClosure(G1CollectorPolicy* g1_policy) : _g1_policy(g1_policy) {} bool doHeapRegion(HeapRegion* r) { _g1_policy->_bytes_in_collection_set_before_gc += r->used(); return false; } }; void G1CollectorPolicy::count_CS_bytes_used() { CountCSClosure cs_closure(this); _g1->collection_set_iterate(&cs_closure); } static void print_indent(int level) { for (int j = 0; j < level+1; ++j) gclog_or_tty->print(" "); } void G1CollectorPolicy::print_summary (int level, const char* str, NumberSeq* seq) const { double sum = seq->sum(); print_indent(level); gclog_or_tty->print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)", str, sum / 1000.0, seq->avg()); } void G1CollectorPolicy::print_summary_sd (int level, const char* str, NumberSeq* seq) const { print_summary(level, str, seq); print_indent(level + 5); gclog_or_tty->print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)", seq->num(), seq->sd(), seq->maximum()); } void G1CollectorPolicy::check_other_times(int level, NumberSeq* other_times_ms, NumberSeq* calc_other_times_ms) const { bool should_print = false; double max_sum = MAX2(fabs(other_times_ms->sum()), fabs(calc_other_times_ms->sum())); double min_sum = MIN2(fabs(other_times_ms->sum()), fabs(calc_other_times_ms->sum())); double sum_ratio = max_sum / min_sum; if (sum_ratio > 1.1) { should_print = true; print_indent(level + 1); gclog_or_tty->print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###"); } double max_avg = MAX2(fabs(other_times_ms->avg()), fabs(calc_other_times_ms->avg())); double min_avg = MIN2(fabs(other_times_ms->avg()), fabs(calc_other_times_ms->avg())); double avg_ratio = max_avg / min_avg; if (avg_ratio > 1.1) { should_print = true; print_indent(level + 1); gclog_or_tty->print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###"); } if (other_times_ms->sum() < -0.01) { print_indent(level + 1); gclog_or_tty->print_cr("## RECORDED OTHER SUM IS NEGATIVE ###"); } if (other_times_ms->avg() < -0.01) { print_indent(level + 1); gclog_or_tty->print_cr("## RECORDED OTHER AVG IS NEGATIVE ###"); } if (calc_other_times_ms->sum() < -0.01) { should_print = true; print_indent(level + 1); gclog_or_tty->print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###"); } if (calc_other_times_ms->avg() < -0.01) { should_print = true; print_indent(level + 1); gclog_or_tty->print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###"); } if (should_print) print_summary(level, "Other(Calc)", calc_other_times_ms); } void G1CollectorPolicy::print_summary(PauseSummary* summary) const { bool parallel = ParallelGCThreads > 0; MainBodySummary* body_summary = summary->main_body_summary(); PopPreambleSummary* preamble_summary = summary->pop_preamble_summary(); if (summary->get_total_seq()->num() > 0) { print_summary_sd(0, (preamble_summary == NULL) ? "Non-Popular Pauses" : "Popular Pauses", summary->get_total_seq()); if (preamble_summary != NULL) { print_summary(1, "Popularity Preamble", preamble_summary->get_pop_preamble_seq()); print_summary(2, "Update RS", preamble_summary->get_pop_update_rs_seq()); print_summary(2, "Scan RS", preamble_summary->get_pop_scan_rs_seq()); print_summary(2, "Closure App", preamble_summary->get_pop_closure_app_seq()); print_summary(2, "Evacuation", preamble_summary->get_pop_evacuation_seq()); print_summary(2, "Other", preamble_summary->get_pop_other_seq()); { NumberSeq* other_parts[] = { preamble_summary->get_pop_update_rs_seq(), preamble_summary->get_pop_scan_rs_seq(), preamble_summary->get_pop_closure_app_seq(), preamble_summary->get_pop_evacuation_seq() }; NumberSeq calc_other_times_ms(preamble_summary->get_pop_preamble_seq(), 4, other_parts); check_other_times(2, preamble_summary->get_pop_other_seq(), &calc_other_times_ms); } } if (body_summary != NULL) { print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq()); if (parallel) { print_summary(1, "Parallel Time", body_summary->get_parallel_seq()); print_summary(2, "Update RS", body_summary->get_update_rs_seq()); print_summary(2, "Ext Root Scanning", body_summary->get_ext_root_scan_seq()); print_summary(2, "Mark Stack Scanning", body_summary->get_mark_stack_scan_seq()); print_summary(2, "Scan-Only Scanning", body_summary->get_scan_only_seq()); print_summary(2, "Scan RS", body_summary->get_scan_rs_seq()); print_summary(2, "Object Copy", body_summary->get_obj_copy_seq()); print_summary(2, "Termination", body_summary->get_termination_seq()); print_summary(2, "Other", body_summary->get_parallel_other_seq()); { NumberSeq* other_parts[] = { body_summary->get_update_rs_seq(), body_summary->get_ext_root_scan_seq(), body_summary->get_mark_stack_scan_seq(), body_summary->get_scan_only_seq(), body_summary->get_scan_rs_seq(), body_summary->get_obj_copy_seq(), body_summary->get_termination_seq() }; NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(), 7, other_parts); check_other_times(2, body_summary->get_parallel_other_seq(), &calc_other_times_ms); } print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq()); print_summary(1, "Clear CT", body_summary->get_clear_ct_seq()); } else { print_summary(1, "Update RS", body_summary->get_update_rs_seq()); print_summary(1, "Ext Root Scanning", body_summary->get_ext_root_scan_seq()); print_summary(1, "Mark Stack Scanning", body_summary->get_mark_stack_scan_seq()); print_summary(1, "Scan-Only Scanning", body_summary->get_scan_only_seq()); print_summary(1, "Scan RS", body_summary->get_scan_rs_seq()); print_summary(1, "Object Copy", body_summary->get_obj_copy_seq()); } } print_summary(1, "Other", summary->get_other_seq()); { NumberSeq calc_other_times_ms; if (body_summary != NULL) { // not abandoned if (parallel) { // parallel NumberSeq* other_parts[] = { body_summary->get_satb_drain_seq(), (preamble_summary == NULL) ? NULL : preamble_summary->get_pop_preamble_seq(), body_summary->get_parallel_seq(), body_summary->get_clear_ct_seq() }; calc_other_times_ms = NumberSeq (summary->get_total_seq(), 4, other_parts); } else { // serial NumberSeq* other_parts[] = { body_summary->get_satb_drain_seq(), (preamble_summary == NULL) ? NULL : preamble_summary->get_pop_preamble_seq(), body_summary->get_update_rs_seq(), body_summary->get_ext_root_scan_seq(), body_summary->get_mark_stack_scan_seq(), body_summary->get_scan_only_seq(), body_summary->get_scan_rs_seq(), body_summary->get_obj_copy_seq() }; calc_other_times_ms = NumberSeq(summary->get_total_seq(), 8, other_parts); } } else { // abandoned NumberSeq* other_parts[] = { (preamble_summary == NULL) ? NULL : preamble_summary->get_pop_preamble_seq() }; calc_other_times_ms = NumberSeq(summary->get_total_seq(), 1, other_parts); } check_other_times(1, summary->get_other_seq(), &calc_other_times_ms); } } else { print_indent(0); gclog_or_tty->print_cr("none"); } gclog_or_tty->print_cr(""); } void G1CollectorPolicy::print_abandoned_summary(PauseSummary* non_pop_summary, PauseSummary* pop_summary) const { bool printed = false; if (non_pop_summary->get_total_seq()->num() > 0) { printed = true; print_summary(non_pop_summary); } if (pop_summary->get_total_seq()->num() > 0) { printed = true; print_summary(pop_summary); } if (!printed) { print_indent(0); gclog_or_tty->print_cr("none"); gclog_or_tty->print_cr(""); } } void G1CollectorPolicy::print_tracing_info() const { if (TraceGen0Time) { gclog_or_tty->print_cr("ALL PAUSES"); print_summary_sd(0, "Total", _all_pause_times_ms); gclog_or_tty->print_cr(""); gclog_or_tty->print_cr(""); gclog_or_tty->print_cr(" Full Young GC Pauses: %8d", _full_young_pause_num); gclog_or_tty->print_cr(" Partial Young GC Pauses: %8d", _partial_young_pause_num); gclog_or_tty->print_cr(""); gclog_or_tty->print_cr("NON-POPULAR PAUSES"); print_summary(_non_pop_summary); gclog_or_tty->print_cr("POPULAR PAUSES"); print_summary(_pop_summary); gclog_or_tty->print_cr("ABANDONED PAUSES"); print_abandoned_summary(_non_pop_abandoned_summary, _pop_abandoned_summary); gclog_or_tty->print_cr("MISC"); print_summary_sd(0, "Stop World", _all_stop_world_times_ms); print_summary_sd(0, "Yields", _all_yield_times_ms); for (int i = 0; i < _aux_num; ++i) { if (_all_aux_times_ms[i].num() > 0) { char buffer[96]; sprintf(buffer, "Aux%d", i); print_summary_sd(0, buffer, &_all_aux_times_ms[i]); } } size_t all_region_num = _region_num_young + _region_num_tenured; gclog_or_tty->print_cr(" New Regions %8d, Young %8d (%6.2lf%%), " "Tenured %8d (%6.2lf%%)", all_region_num, _region_num_young, (double) _region_num_young / (double) all_region_num * 100.0, _region_num_tenured, (double) _region_num_tenured / (double) all_region_num * 100.0); if (!G1RSBarrierUseQueue) { gclog_or_tty->print_cr("Of %d times conc refinement was enabled, %d (%7.2f%%) " "did zero traversals.", _conc_refine_enabled, _conc_refine_zero_traversals, _conc_refine_enabled > 0 ? 100.0 * (float)_conc_refine_zero_traversals/ (float)_conc_refine_enabled : 0.0); gclog_or_tty->print_cr(" Max # of traversals = %d.", _conc_refine_max_traversals); gclog_or_tty->print_cr(""); } } if (TraceGen1Time) { if (_all_full_gc_times_ms->num() > 0) { gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s", _all_full_gc_times_ms->num(), _all_full_gc_times_ms->sum() / 1000.0); gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg()); gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]", _all_full_gc_times_ms->sd(), _all_full_gc_times_ms->maximum()); } } } void G1CollectorPolicy::print_yg_surv_rate_info() const { #ifndef PRODUCT _short_lived_surv_rate_group->print_surv_rate_summary(); // add this call for any other surv rate groups #endif // PRODUCT } void G1CollectorPolicy::update_conc_refine_data() { unsigned traversals = _g1->concurrent_g1_refine()->disable(); if (traversals == 0) _conc_refine_zero_traversals++; _conc_refine_max_traversals = MAX2(_conc_refine_max_traversals, (size_t)traversals); if (G1PolicyVerbose > 1) gclog_or_tty->print_cr("Did a CR traversal series: %d traversals.", traversals); double multiplier = 1.0; if (traversals == 0) { multiplier = 4.0; } else if (traversals > (size_t)G1ConcRefineTargTraversals) { multiplier = 1.0/1.5; } else if (traversals < (size_t)G1ConcRefineTargTraversals) { multiplier = 1.5; } if (G1PolicyVerbose > 1) { gclog_or_tty->print_cr(" Multiplier = %7.2f.", multiplier); gclog_or_tty->print(" Delta went from %d regions to ", _conc_refine_current_delta); } _conc_refine_current_delta = MIN2(_g1->n_regions(), (size_t)(_conc_refine_current_delta * multiplier)); _conc_refine_current_delta = MAX2(_conc_refine_current_delta, (size_t)1); if (G1PolicyVerbose > 1) { gclog_or_tty->print_cr("%d regions.", _conc_refine_current_delta); } _conc_refine_enabled++; } void G1CollectorPolicy::set_single_region_collection_set(HeapRegion* hr) { assert(collection_set() == NULL, "Must be no current CS."); _collection_set_size = 0; _collection_set_bytes_used_before = 0; add_to_collection_set(hr); count_CS_bytes_used(); } bool G1CollectorPolicy::should_add_next_region_to_young_list() { assert(in_young_gc_mode(), "should be in young GC mode"); bool ret; size_t young_list_length = _g1->young_list_length(); size_t young_list_max_length = _young_list_target_length; if (G1FixedEdenSize) { young_list_max_length -= _max_survivor_regions; } if (young_list_length < young_list_max_length) { ret = true; ++_region_num_young; } else { ret = false; ++_region_num_tenured; } return ret; } #ifndef PRODUCT // for debugging, bit of a hack... static char* region_num_to_mbs(int length) { static char buffer[64]; double bytes = (double) (length * HeapRegion::GrainBytes); double mbs = bytes / (double) (1024 * 1024); sprintf(buffer, "%7.2lfMB", mbs); return buffer; } #endif // PRODUCT void G1CollectorPolicy::checkpoint_conc_overhead() { double conc_overhead = 0.0; if (G1AccountConcurrentOverhead) conc_overhead = COTracker::totalPredConcOverhead(); _mmu_tracker->update_conc_overhead(conc_overhead); #if 0 gclog_or_tty->print(" CO %1.4lf TARGET %1.4lf", conc_overhead, _mmu_tracker->max_gc_time()); #endif } size_t G1CollectorPolicy::max_regions(int purpose) { switch (purpose) { case GCAllocForSurvived: return _max_survivor_regions; case GCAllocForTenured: return REGIONS_UNLIMITED; default: ShouldNotReachHere(); return REGIONS_UNLIMITED; }; } // Calculates survivor space parameters. void G1CollectorPolicy::calculate_survivors_policy() { if (!G1UseSurvivorSpace) { return; } if (G1FixedSurvivorSpaceSize == 0) { _max_survivor_regions = _young_list_target_length / SurvivorRatio; } else { _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes; } if (G1FixedTenuringThreshold) { _tenuring_threshold = MaxTenuringThreshold; } else { _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold( HeapRegion::GrainWords * _max_survivor_regions); } } void G1CollectorPolicy_BestRegionsFirst:: set_single_region_collection_set(HeapRegion* hr) { G1CollectorPolicy::set_single_region_collection_set(hr); _collectionSetChooser->removeRegion(hr); } bool G1CollectorPolicy_BestRegionsFirst::should_do_collection_pause(size_t word_size) { assert(_g1->regions_accounted_for(), "Region leakage!"); // Initiate a pause when we reach the steady-state "used" target. size_t used_hard = (_g1->capacity() / 100) * G1SteadyStateUsed; size_t used_soft = MAX2((_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta), used_hard/2); size_t used = _g1->used(); double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0; size_t young_list_length = _g1->young_list_length(); size_t young_list_max_length = _young_list_target_length; if (G1FixedEdenSize) { young_list_max_length -= _max_survivor_regions; } bool reached_target_length = young_list_length >= young_list_max_length; if (in_young_gc_mode()) { if (reached_target_length) { assert( young_list_length > 0 && _g1->young_list_length() > 0, "invariant" ); _target_pause_time_ms = max_pause_time_ms; return true; } } else { guarantee( false, "should not reach here" ); } return false; } #ifndef PRODUCT class HRSortIndexIsOKClosure: public HeapRegionClosure { CollectionSetChooser* _chooser; public: HRSortIndexIsOKClosure(CollectionSetChooser* chooser) : _chooser(chooser) {} bool doHeapRegion(HeapRegion* r) { if (!r->continuesHumongous()) { assert(_chooser->regionProperlyOrdered(r), "Ought to be."); } return false; } }; bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() { HRSortIndexIsOKClosure cl(_collectionSetChooser); _g1->heap_region_iterate(&cl); return true; } #endif void G1CollectorPolicy_BestRegionsFirst:: record_collection_pause_start(double start_time_sec, size_t start_used) { G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used); } class NextNonCSElemFinder: public HeapRegionClosure { HeapRegion* _res; public: NextNonCSElemFinder(): _res(NULL) {} bool doHeapRegion(HeapRegion* r) { if (!r->in_collection_set()) { _res = r; return true; } else { return false; } } HeapRegion* res() { return _res; } }; class KnownGarbageClosure: public HeapRegionClosure { CollectionSetChooser* _hrSorted; public: KnownGarbageClosure(CollectionSetChooser* hrSorted) : _hrSorted(hrSorted) {} bool doHeapRegion(HeapRegion* r) { // We only include humongous regions in collection // sets when concurrent mark shows that their contained object is // unreachable. // Do we have any marking information for this region? if (r->is_marked()) { // We don't include humongous regions in collection // sets because we collect them immediately at the end of a marking // cycle. We also don't include young regions because we *must* // include them in the next collection pause. if (!r->isHumongous() && !r->is_young()) { _hrSorted->addMarkedHeapRegion(r); } } return false; } }; class ParKnownGarbageHRClosure: public HeapRegionClosure { CollectionSetChooser* _hrSorted; jint _marked_regions_added; jint _chunk_size; jint _cur_chunk_idx; jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end) int _worker; int _invokes; void get_new_chunk() { _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size); _cur_chunk_end = _cur_chunk_idx + _chunk_size; } void add_region(HeapRegion* r) { if (_cur_chunk_idx == _cur_chunk_end) { get_new_chunk(); } assert(_cur_chunk_idx < _cur_chunk_end, "postcondition"); _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r); _marked_regions_added++; _cur_chunk_idx++; } public: ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted, jint chunk_size, int worker) : _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker), _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0), _invokes(0) {} bool doHeapRegion(HeapRegion* r) { // We only include humongous regions in collection // sets when concurrent mark shows that their contained object is // unreachable. _invokes++; // Do we have any marking information for this region? if (r->is_marked()) { // We don't include humongous regions in collection // sets because we collect them immediately at the end of a marking // cycle. // We also do not include young regions in collection sets if (!r->isHumongous() && !r->is_young()) { add_region(r); } } return false; } jint marked_regions_added() { return _marked_regions_added; } int invokes() { return _invokes; } }; class ParKnownGarbageTask: public AbstractGangTask { CollectionSetChooser* _hrSorted; jint _chunk_size; G1CollectedHeap* _g1; public: ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) : AbstractGangTask("ParKnownGarbageTask"), _hrSorted(hrSorted), _chunk_size(chunk_size), _g1(G1CollectedHeap::heap()) {} void work(int i) { ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i); // Back to zero for the claim value. _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i, HeapRegion::InitialClaimValue); jint regions_added = parKnownGarbageCl.marked_regions_added(); _hrSorted->incNumMarkedHeapRegions(regions_added); if (G1PrintParCleanupStats) { gclog_or_tty->print(" Thread %d called %d times, added %d regions to list.\n", i, parKnownGarbageCl.invokes(), regions_added); } } }; void G1CollectorPolicy_BestRegionsFirst:: record_concurrent_mark_cleanup_end(size_t freed_bytes, size_t max_live_bytes) { double start; if (G1PrintParCleanupStats) start = os::elapsedTime(); record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes); _collectionSetChooser->clearMarkedHeapRegions(); double clear_marked_end; if (G1PrintParCleanupStats) { clear_marked_end = os::elapsedTime(); gclog_or_tty->print_cr(" clear marked regions + work1: %8.3f ms.", (clear_marked_end - start)*1000.0); } if (ParallelGCThreads > 0) { const size_t OverpartitionFactor = 4; const size_t MinChunkSize = 8; const size_t ChunkSize = MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor), MinChunkSize); _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(), ChunkSize); ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser, (int) ChunkSize); _g1->workers()->run_task(&parKnownGarbageTask); assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue), "sanity check"); } else { KnownGarbageClosure knownGarbagecl(_collectionSetChooser); _g1->heap_region_iterate(&knownGarbagecl); } double known_garbage_end; if (G1PrintParCleanupStats) { known_garbage_end = os::elapsedTime(); gclog_or_tty->print_cr(" compute known garbage: %8.3f ms.", (known_garbage_end - clear_marked_end)*1000.0); } _collectionSetChooser->sortMarkedHeapRegions(); double sort_end; if (G1PrintParCleanupStats) { sort_end = os::elapsedTime(); gclog_or_tty->print_cr(" sorting: %8.3f ms.", (sort_end - known_garbage_end)*1000.0); } record_concurrent_mark_cleanup_end_work2(); double work2_end; if (G1PrintParCleanupStats) { work2_end = os::elapsedTime(); gclog_or_tty->print_cr(" work2: %8.3f ms.", (work2_end - sort_end)*1000.0); } } // Add the heap region to the collection set and return the conservative // estimate of the number of live bytes. void G1CollectorPolicy:: add_to_collection_set(HeapRegion* hr) { if (G1TraceRegions) { gclog_or_tty->print_cr("added region to cset %d:["PTR_FORMAT", "PTR_FORMAT"], " "top "PTR_FORMAT", young %s", hr->hrs_index(), hr->bottom(), hr->end(), hr->top(), (hr->is_young()) ? "YES" : "NO"); } if (_g1->mark_in_progress()) _g1->concurrent_mark()->registerCSetRegion(hr); assert(!hr->in_collection_set(), "should not already be in the CSet"); hr->set_in_collection_set(true); hr->set_next_in_collection_set(_collection_set); _collection_set = hr; _collection_set_size++; _collection_set_bytes_used_before += hr->used(); _g1->register_region_with_in_cset_fast_test(hr); } void G1CollectorPolicy_BestRegionsFirst:: choose_collection_set(HeapRegion* pop_region) { double non_young_start_time_sec; start_recording_regions(); if (pop_region != NULL) { _target_pause_time_ms = (double) G1MaxPauseTimeMS; } else { guarantee(_target_pause_time_ms > -1.0, "_target_pause_time_ms should have been set!"); } // pop region is either null (and so is CS), or else it *is* the CS. assert(_collection_set == pop_region, "Precondition"); double base_time_ms = predict_base_elapsed_time_ms(_pending_cards); double predicted_pause_time_ms = base_time_ms; double target_time_ms = _target_pause_time_ms; double time_remaining_ms = target_time_ms - base_time_ms; // the 10% and 50% values are arbitrary... if (time_remaining_ms < 0.10*target_time_ms) { time_remaining_ms = 0.50 * target_time_ms; _within_target = false; } else { _within_target = true; } // We figure out the number of bytes available for future to-space. // For new regions without marking information, we must assume the // worst-case of complete survival. If we have marking information for a // region, we can bound the amount of live data. We can add a number of // such regions, as long as the sum of the live data bounds does not // exceed the available evacuation space. size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes; size_t expansion_bytes = _g1->expansion_regions() * HeapRegion::GrainBytes; if (pop_region == NULL) { _collection_set_bytes_used_before = 0; _collection_set_size = 0; } // Adjust for expansion and slop. max_live_bytes = max_live_bytes + expansion_bytes; assert(pop_region != NULL || _g1->regions_accounted_for(), "Region leakage!"); HeapRegion* hr; if (in_young_gc_mode()) { double young_start_time_sec = os::elapsedTime(); if (G1PolicyVerbose > 0) { gclog_or_tty->print_cr("Adding %d young regions to the CSet", _g1->young_list_length()); } _young_cset_length = 0; _last_young_gc_full = full_young_gcs() ? true : false; if (_last_young_gc_full) ++_full_young_pause_num; else ++_partial_young_pause_num; hr = _g1->pop_region_from_young_list(); while (hr != NULL) { assert( hr->young_index_in_cset() == -1, "invariant" ); assert( hr->age_in_surv_rate_group() != -1, "invariant" ); hr->set_young_index_in_cset((int) _young_cset_length); ++_young_cset_length; double predicted_time_ms = predict_region_elapsed_time_ms(hr, true); time_remaining_ms -= predicted_time_ms; predicted_pause_time_ms += predicted_time_ms; if (hr == pop_region) { // The popular region was young. Skip over it. assert(hr->in_collection_set(), "It's the pop region."); } else { assert(!hr->in_collection_set(), "It's not the pop region."); add_to_collection_set(hr); record_cset_region(hr, true); } max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes); if (G1PolicyVerbose > 0) { gclog_or_tty->print_cr(" Added [" PTR_FORMAT ", " PTR_FORMAT") to CS.", hr->bottom(), hr->end()); gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)", max_live_bytes/K); } hr = _g1->pop_region_from_young_list(); } record_scan_only_regions(_g1->young_list_scan_only_length()); double young_end_time_sec = os::elapsedTime(); _recorded_young_cset_choice_time_ms = (young_end_time_sec - young_start_time_sec) * 1000.0; non_young_start_time_sec = os::elapsedTime(); if (_young_cset_length > 0 && _last_young_gc_full) { // don't bother adding more regions... goto choose_collection_set_end; } } else if (pop_region != NULL) { // We're not in young mode, and we chose a popular region; don't choose // any more. return; } if (!in_young_gc_mode() || !full_young_gcs()) { bool should_continue = true; NumberSeq seq; double avg_prediction = 100000000000000000.0; // something very large do { hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms, avg_prediction); if (hr != NULL && !hr->popular()) { double predicted_time_ms = predict_region_elapsed_time_ms(hr, false); time_remaining_ms -= predicted_time_ms; predicted_pause_time_ms += predicted_time_ms; add_to_collection_set(hr); record_cset_region(hr, false); max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes); if (G1PolicyVerbose > 0) { gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)", max_live_bytes/K); } seq.add(predicted_time_ms); avg_prediction = seq.avg() + seq.sd(); } should_continue = ( hr != NULL) && ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0 : _collection_set_size < _young_list_fixed_length ); } while (should_continue); if (!adaptive_young_list_length() && _collection_set_size < _young_list_fixed_length) _should_revert_to_full_young_gcs = true; } choose_collection_set_end: count_CS_bytes_used(); end_recording_regions(); double non_young_end_time_sec = os::elapsedTime(); _recorded_non_young_cset_choice_time_ms = (non_young_end_time_sec - non_young_start_time_sec) * 1000.0; } void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() { G1CollectorPolicy::record_full_collection_end(); _collectionSetChooser->updateAfterFullCollection(); } void G1CollectorPolicy_BestRegionsFirst:: expand_if_possible(size_t numRegions) { size_t expansion_bytes = numRegions * HeapRegion::GrainBytes; _g1->expand(expansion_bytes); } void G1CollectorPolicy_BestRegionsFirst:: record_collection_pause_end(bool popular, bool abandoned) { G1CollectorPolicy::record_collection_pause_end(popular, abandoned); assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end."); } // Local Variables: *** // c-indentation-style: gnu *** // End: ***