Mercurial > hg > graal-compiler
view src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp @ 2044:06f017f7daa7
Merge.
author | Thomas Wuerthinger <wuerthinger@ssw.jku.at> |
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date | Fri, 07 Jan 2011 18:18:08 +0100 |
parents | 016a3628c885 |
children | 0fa27f37d4d4 |
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/* * Copyright (c) 2001, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "gc_implementation/g1/concurrentG1Refine.hpp" #include "gc_implementation/g1/concurrentMark.hpp" #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" #include "gc_implementation/g1/g1CollectorPolicy.hpp" #include "gc_implementation/g1/heapRegionRemSet.hpp" #include "gc_implementation/shared/gcPolicyCounters.hpp" #include "runtime/arguments.hpp" #include "runtime/java.hpp" #include "runtime/mutexLocker.hpp" #include "utilities/debug.hpp" #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 }; // 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(G1CollectedHeap::use_parallel_gc_threads() ? 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()), _summary(new Summary()), #ifndef PRODUCT _cur_clear_ct_time_ms(0.0), _min_clear_cc_time_ms(-1.0), _max_clear_cc_time_ms(-1.0), _cur_clear_cc_time_ms(0.0), _cum_clear_cc_time_ms(0.0), _num_cc_clears(0L), #endif _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]), _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)), _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)), _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) MaxGCPauseMillis), // </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)), _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()), // 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), _initiate_conc_mark_if_possible(false), _during_initial_mark_pause(false), _should_revert_to_full_young_gcs(false), _last_full_young_gc(false), _prev_collection_pause_used_at_end_bytes(0), _collection_set(NULL), _collection_set_size(0), _collection_set_bytes_used_before(0), // Incremental CSet attributes _inc_cset_build_state(Inactive), _inc_cset_head(NULL), _inc_cset_tail(NULL), _inc_cset_size(0), _inc_cset_young_index(0), _inc_cset_bytes_used_before(0), _inc_cset_max_finger(NULL), _inc_cset_recorded_young_bytes(0), _inc_cset_recorded_rs_lengths(0), _inc_cset_predicted_elapsed_time_ms(0.0), _inc_cset_predicted_bytes_to_copy(0), #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), _gc_overhead_perc(0.0) { // Set up the region size and associated fields. Given that the // policy is created before the heap, we have to set this up here, // so it's done as soon as possible. HeapRegion::setup_heap_region_size(Arguments::min_heap_size()); HeapRegionRemSet::setup_remset_size(); // Verify PLAB sizes const uint region_size = HeapRegion::GrainWords; if (YoungPLABSize > region_size || OldPLABSize > region_size) { char buffer[128]; jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most %u", OldPLABSize > region_size ? "Old" : "Young", region_size); vm_exit_during_initialization(buffer); } _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime()); _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0; _par_last_gc_worker_start_times_ms = new double[_parallel_gc_threads]; _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_update_rs_times_ms = new double[_parallel_gc_threads]; _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads]; _par_last_scan_rs_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]; _par_last_termination_attempts = new double[_parallel_gc_threads]; _par_last_gc_worker_end_times_ms = new double[_parallel_gc_threads]; // start conservatively _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis; // <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]); _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> // Below, we might need to calculate the pause time target based on // the pause interval. When we do so we are going to give G1 maximum // flexibility and allow it to do pauses when it needs to. So, we'll // arrange that the pause interval to be pause time target + 1 to // ensure that a) the pause time target is maximized with respect to // the pause interval and b) we maintain the invariant that pause // time target < pause interval. If the user does not want this // maximum flexibility, they will have to set the pause interval // explicitly. // First make sure that, if either parameter is set, its value is // reasonable. if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) { if (MaxGCPauseMillis < 1) { vm_exit_during_initialization("MaxGCPauseMillis should be " "greater than 0"); } } if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { if (GCPauseIntervalMillis < 1) { vm_exit_during_initialization("GCPauseIntervalMillis should be " "greater than 0"); } } // Then, if the pause time target parameter was not set, set it to // the default value. if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) { if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { // The default pause time target in G1 is 200ms FLAG_SET_DEFAULT(MaxGCPauseMillis, 200); } else { // We do not allow the pause interval to be set without the // pause time target vm_exit_during_initialization("GCPauseIntervalMillis cannot be set " "without setting MaxGCPauseMillis"); } } // Then, if the interval parameter was not set, set it according to // the pause time target (this will also deal with the case when the // pause time target is the default value). if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) { FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1); } // Finally, make sure that the two parameters are consistent. if (MaxGCPauseMillis >= GCPauseIntervalMillis) { char buffer[256]; jio_snprintf(buffer, 256, "MaxGCPauseMillis (%u) should be less than " "GCPauseIntervalMillis (%u)", MaxGCPauseMillis, GCPauseIntervalMillis); vm_exit_during_initialization(buffer); } double max_gc_time = (double) MaxGCPauseMillis / 1000.0; double time_slice = (double) GCPauseIntervalMillis / 1000.0; _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time); _sigma = (double) G1ConfidencePercent / 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 G1FixedSurvivorSpaceSize is 0 which means the size is not // fixed, then _max_survivor_regions will be calculated at // calculate_young_list_target_length during initialization _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes; assert(GCTimeRatio > 0, "we should have set it to a default value set_g1_gc_flags() " "if a user set it to 0"); _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio)); 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(); } // The easiest way to deal with the parsing of the NewSize / // MaxNewSize / etc. parameteres is to re-use the code in the // TwoGenerationCollectorPolicy class. This is similar to what // ParallelScavenge does with its GenerationSizer class (see // ParallelScavengeHeap::initialize()). We might change this in the // future, but it's a good start. class G1YoungGenSizer : public TwoGenerationCollectorPolicy { size_t size_to_region_num(size_t byte_size) { return MAX2((size_t) 1, byte_size / HeapRegion::GrainBytes); } public: G1YoungGenSizer() { initialize_flags(); initialize_size_info(); } size_t min_young_region_num() { return size_to_region_num(_min_gen0_size); } size_t initial_young_region_num() { return size_to_region_num(_initial_gen0_size); } size_t max_young_region_num() { return size_to_region_num(_max_gen0_size); } }; void G1CollectorPolicy::init() { // Set aside an initial future to_space. _g1 = G1CollectedHeap::heap(); assert(Heap_lock->owned_by_self(), "Locking discipline."); initialize_gc_policy_counters(); if (G1Gen) { _in_young_gc_mode = true; G1YoungGenSizer sizer; size_t initial_region_num = sizer.initial_young_region_num(); if (UseAdaptiveSizePolicy) { set_adaptive_young_list_length(true); _young_list_fixed_length = 0; } else { set_adaptive_young_list_length(false); _young_list_fixed_length = initial_region_num; } _free_regions_at_end_of_collection = _g1->free_regions(); calculate_young_list_min_length(); guarantee( _young_list_min_length == 0, "invariant, not enough info" ); calculate_young_list_target_length(); } else { _young_list_fixed_length = 0; _in_young_gc_mode = false; } // We may immediately start allocating regions and placing them on the // collection set list. Initialize the per-collection set info start_incremental_cset_building(); } // 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(); size_t min_regions = (size_t) ceil(alloc_rate_ms * when_ms); size_t current_region_num = _g1->young_list()->length(); _young_list_min_length = min_regions + current_region_num; } } void G1CollectorPolicy::calculate_young_list_target_length() { if (adaptive_young_list_length()) { size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq); calculate_young_list_target_length(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; } // Make sure we allow the application to allocate at least one // region before we need to do a collection again. size_t min_length = _g1->young_list()->length() + 1; _young_list_target_length = MAX2(_young_list_target_length, min_length); calculate_max_gc_locker_expansion(); calculate_survivors_policy(); } void G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths) { guarantee( adaptive_young_list_length(), "pre-condition" ); guarantee( !_in_marking_window || !_last_full_young_gc, "invariant" ); double start_time_sec = os::elapsedTime(); size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1ReservePercent); 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(); 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 = predict_young_card_num(adj_rs_lengths); 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 init_free_regions = MAX2((size_t)0, _free_regions_at_end_of_collection - reserve_regions); // if we're still under the pause target... if (base_time_ms <= target_pause_time_ms) { // We make sure that the shortest young length that makes sense // fits within the target pause time. size_t min_young_length = 1; if (predict_will_fit(min_young_length, base_time_ms, init_free_regions, target_pause_time_ms)) { // The shortest young length will fit within the target pause time; // we'll now check whether the absolute maximum number of young // regions will fit in the target pause time. If not, we'll do // a binary search between min_young_length and max_young_length size_t abs_max_young_length = _free_regions_at_end_of_collection - 1; size_t max_young_length = abs_max_young_length; if (max_young_length > min_young_length) { // Let's check if the initial max young length will fit within the // target pause. If so then there is no need to search for a maximal // young length - we'll return the initial maximum if (predict_will_fit(max_young_length, base_time_ms, init_free_regions, target_pause_time_ms)) { // The maximum young length will satisfy the target pause time. // We are done so set min young length to this maximum length. // The code after the loop will then set final_young_length using // the value cached in the minimum length. min_young_length = max_young_length; } else { // The maximum possible number of young regions will not fit within // the target pause time so let's search.... size_t diff = (max_young_length - min_young_length) / 2; max_young_length = min_young_length + diff; while (max_young_length > min_young_length) { if (predict_will_fit(max_young_length, base_time_ms, init_free_regions, target_pause_time_ms)) { // The current max young length will fit within the target // pause time. Note we do not exit the loop here. By setting // min = max, and then increasing the max below means that // we will continue searching for an upper bound in the // range [max..max+diff] min_young_length = max_young_length; } diff = (max_young_length - min_young_length) / 2; max_young_length = min_young_length + diff; } // the above loop found a maximal young length that will fit // within the target pause time. } assert(min_young_length <= abs_max_young_length, "just checking"); } final_young_length = min_young_length; } } // and we're done! // we should have at least one region in the target young length _young_list_target_length = final_young_length + _recorded_survivor_regions; // 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_LENGTH // leave this in for debugging, just in case gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT ", " "elapsed %1.2lf ms, (%s%s) " SIZE_FORMAT SIZE_FORMAT, target_pause_time_ms, _young_list_target_length elapsed_time_ms, full_young_gcs() ? "full" : "partial", during_initial_mark_pause() ? " i-m" : "", _in_marking_window, _in_marking_window_im); #endif // TRACE_CALC_YOUNG_LENGTH if (_young_list_target_length < _young_list_min_length) { // bummer; this means that, if we do a pause when the maximal // length 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. #ifdef TRACE_CALC_YOUNG_LENGTH // leave this in for debugging, just in case gclog_or_tty->print_cr("adjusted target length from " SIZE_FORMAT " to " SIZE_FORMAT, _young_list_target_length, _young_list_min_length); #endif // TRACE_CALC_YOUNG_LENGTH _young_list_target_length = _young_list_min_length; } } else { // we are in a partially-young mode or we've run out of regions (due // to evacuation failure) #ifdef TRACE_CALC_YOUNG_LENGTH // leave this in for debugging, just in case gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT _young_list_min_length); #endif // TRACE_CALC_YOUNG_LENGTH // we'll do the pause as soon as possible by choosing the minimum _young_list_target_length = _young_list_min_length; } _rs_lengths_prediction = rs_lengths; } // This is used by: calculate_young_list_target_length(rs_length). It // returns true iff: // the predicted pause time for the given young list will not overflow // the target pause time // and: // the predicted amount of surviving data will not overflow the // the amount of free space available for survivor regions. // bool G1CollectorPolicy::predict_will_fit(size_t young_length, double base_time_ms, size_t init_free_regions, double target_pause_time_ms) { 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; 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); double pause_time_ms = base_time_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 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! 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_length(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; _all_full_gc_times_ms->add(full_gc_time_ms); update_recent_gc_times(end_sec, full_gc_time_ms); _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; clear_initiate_conc_mark_if_possible(); clear_during_initial_mark_pause(); _known_garbage_bytes = 0; _known_garbage_ratio = 0.0; _in_marking_window = false; _in_marking_window_im = false; _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(); // Reset survivors SurvRateGroup. _survivor_surv_rate_group->reset(); calculate_young_list_min_length(); calculate_young_list_target_length(); } 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() == _g1->recalculate_used(), err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT, _g1->used(), _g1->recalculate_used())); 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_gc_worker_start_times_ms[i] = -1234.0; _par_last_ext_root_scan_times_ms[i] = -1234.0; _par_last_mark_stack_scan_times_ms[i] = -1234.0; _par_last_update_rs_times_ms[i] = -1234.0; _par_last_update_rs_processed_buffers[i] = -1234.0; _par_last_scan_rs_times_ms[i] = -1234.0; _par_last_obj_copy_times_ms[i] = -1234.0; _par_last_termination_times_ms[i] = -1234.0; _par_last_termination_attempts[i] = -1234.0; _par_last_gc_worker_end_times_ms[i] = -1234.0; } #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(); _survivors_age_table.clear(); assert( verify_young_ages(), "region age verification" ); } 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; assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now"); clear_during_initial_mark_pause(); _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); 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; _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() { 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++; } 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_length(); } } 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_sizes(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 (G1CollectedHeap::use_parallel_gc_threads()) { 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 (G1CollectedHeap::use_parallel_gc_threads()) { 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 (G1CollectedHeap::use_parallel_gc_threads()) { 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 (G1CollectedHeap::use_parallel_gc_threads()) { 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() { double end_time_sec = os::elapsedTime(); double elapsed_ms = _last_pause_time_ms; bool parallel = G1CollectedHeap::use_parallel_gc_threads(); 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; bool update_stats = !_g1->evacuation_failed(); #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 if (in_young_gc_mode()) { last_pause_included_initial_mark = during_initial_mark_pause(); if (last_pause_included_initial_mark) record_concurrent_mark_init_end_pre(0.0); size_t min_used_targ = (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent; if (!_g1->mark_in_progress() && !_last_full_young_gc) { assert(!last_pause_included_initial_mark, "invariant"); if (cur_used_bytes > min_used_targ && cur_used_bytes > _prev_collection_pause_used_at_end_bytes) { assert(!during_initial_mark_pause(), "we should not see this here"); // Note: this might have already been set, if during the last // pause we decided to start a cycle but at the beginning of // this pause we decided to postpone it. That's OK. set_initiate_conc_mark_if_possible(); } } _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 (update_stats) { _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; if (recent_avg_pause_time_ratio() < 0.0 || (recent_avg_pause_time_ratio() - 1.0 > 0.0)) { #ifndef PRODUCT // Dump info to allow post-facto debugging gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds"); gclog_or_tty->print_cr("-------------------------------------------"); gclog_or_tty->print_cr("Recent GC Times (ms):"); _recent_gc_times_ms->dump(); gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec); _recent_prev_end_times_for_all_gcs_sec->dump(); gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f", _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio()); // In debug mode, terminate the JVM if the user wants to debug at this point. assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above"); #endif // !PRODUCT // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in // CR 6902692 by redoing the manner in which the ratio is incrementally computed. if (_recent_avg_pause_time_ratio < 0.0) { _recent_avg_pause_time_ratio = 0.0; } else { assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant"); _recent_avg_pause_time_ratio = 1.0; } } } if (G1PolicyVerbose > 1) { gclog_or_tty->print_cr(" Recording collection pause(%d)", _n_pauses); } PauseSummary* summary = _summary; 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 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 = _cur_collection_par_time_ms - (update_rs_time + ext_root_scan_time + mark_stack_scan_time + scan_rs_time + obj_copy_time + termination_time); if (update_stats) { 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_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); 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 (_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_rs_time + obj_copy_time; } if (PrintGCDetails) { gclog_or_tty->print_cr("%s, %1.8lf secs]", (last_pause_included_initial_mark) ? " (initial-mark)" : "", elapsed_ms / 1000.0); 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 (parallel) { print_stats(1, "Parallel Time", _cur_collection_par_time_ms); print_par_stats(2, "GC Worker Start Time", _par_last_gc_worker_start_times_ms, false); print_par_stats(2, "Update RS", _par_last_update_rs_times_ms); print_par_sizes(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 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_par_sizes(3, "Termination Attempts", _par_last_termination_attempts, true); print_par_stats(2, "GC Worker End Time", _par_last_gc_worker_end_times_ms, false); print_stats(2, "Other", parallel_other_time); print_stats(1, "Clear CT", _cur_clear_ct_time_ms); } else { print_stats(1, "Update RS", update_rs_time); 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 RS", scan_rs_time); print_stats(1, "Object Copying", obj_copy_time); } #ifndef PRODUCT print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms); print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms); print_stats(1, "Min Clear CC", _min_clear_cc_time_ms); print_stats(1, "Max Clear CC", _max_clear_cc_time_ms); if (_num_cc_clears > 0) { print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears)); } #endif print_stats(1, "Other", other_time_ms); print_stats(2, "Choose CSet", _recorded_young_cset_choice_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); if (update_stats) { 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 (during_initial_mark_pause()) { 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 (update_stats) { 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); } 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_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) MaxGCPauseMillis - 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) MaxGCPauseMillis; } _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 " "PENDING_CARDS %d %d " "CARDS_SCANNED %d %d " "RS_LENGTHS %d %d " "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_non_young_regions, _predicted_pending_cards, _pending_cards, _predicted_cards_scanned, cards_scanned, _predicted_rs_lengths, _max_rs_lengths, _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(); calculate_young_list_min_length(); calculate_young_list_target_length(); // Note that _mmu_tracker->max_gc_time() returns the time in seconds. double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0; adjust_concurrent_refinement(update_rs_time, update_rs_processed_buffers, update_rs_time_goal_ms); // </NEW PREDICTION> } // <NEW PREDICTION> void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time, double update_rs_processed_buffers, double goal_ms) { DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine(); if (G1UseAdaptiveConcRefinement) { const int k_gy = 3, k_gr = 6; const double inc_k = 1.1, dec_k = 0.9; int g = cg1r->green_zone(); if (update_rs_time > goal_ms) { g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing. } else { if (update_rs_time < goal_ms && update_rs_processed_buffers > g) { g = (int)MAX2(g * inc_k, g + 1.0); } } // Change the refinement threads params cg1r->set_green_zone(g); cg1r->set_yellow_zone(g * k_gy); cg1r->set_red_zone(g * k_gr); cg1r->reinitialize_threads(); int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1); int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta, cg1r->yellow_zone()); // Change the barrier params dcqs.set_process_completed_threshold(processing_threshold); dcqs.set_max_completed_queue(cg1r->red_zone()); } int curr_queue_size = dcqs.completed_buffers_num(); if (curr_queue_size >= cg1r->yellow_zone()) { dcqs.set_completed_queue_padding(curr_queue_size); } else { dcqs.set_completed_queue_padding(0); } dcqs.notify_if_necessary(); } 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_young_regions = 0; _recorded_non_young_regions = 0; #if PREDICTIONS_VERBOSE _recorded_marked_bytes = 0; _recorded_young_bytes = 0; _predicted_bytes_to_copy = 0; _predicted_rs_lengths = 0; _predicted_cards_scanned = 0; #endif // PREDICTIONS_VERBOSE } void G1CollectorPolicy::record_cset_region_info(HeapRegion* hr, bool young) { #if PREDICTIONS_VERBOSE if (!young) { _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_non_young_cset_region(HeapRegion* hr) { assert(!hr->is_young(), "should not call this"); ++_recorded_non_young_regions; record_cset_region_info(hr, false); } void G1CollectorPolicy::set_recorded_young_regions(size_t n_regions) { _recorded_young_regions = n_regions; } void G1CollectorPolicy::set_recorded_young_bytes(size_t bytes) { #if PREDICTIONS_VERBOSE _recorded_young_bytes = bytes; #endif // PREDICTIONS_VERBOSE } void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) { _recorded_rs_lengths = rs_lengths; } void G1CollectorPolicy::set_predicted_bytes_to_copy(size_t bytes) { _predicted_bytes_to_copy = bytes; } void G1CollectorPolicy::end_recording_regions() { // The _predicted_pause_time_ms field is referenced in code // not under PREDICTIONS_VERBOSE. Let's initialize it. _predicted_pause_time_ms = -1.0; #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_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_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); // We might want to do something different here. However, // right now we don't support the non-generational G1 mode // (and in fact we are planning to remove the associated code, // see CR 6814390). So, let's leave it as is and this will be // removed some time in the future ShouldNotReachHere(); set_during_initial_mark_pause(); } 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) MaxGCPauseMillis; 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)MaxGCPauseMillis/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)MaxGCPauseMillis/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)MaxGCPauseMillis/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 || G1CollectedHeap::use_parallel_gc_threads()) || _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 || G1CollectedHeap::use_parallel_gc_threads()) || 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 ((recent_avg_pause_time_ratio() * 100.0) > _gc_overhead_perc) { // We will double the existing space, or take // G1ExpandByPercentOfAvailable % 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 * G1ExpandByPercentOfAvailable / 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 = G1CollectedHeap::use_parallel_gc_threads(); MainBodySummary* body_summary = summary->main_body_summary(); if (summary->get_total_seq()->num() > 0) { print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq()); 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 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_rs_seq(), body_summary->get_obj_copy_seq(), body_summary->get_termination_seq() }; NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(), 6, 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 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()); { if (body_summary != NULL) { NumberSeq calc_other_times_ms; if (parallel) { // parallel NumberSeq* other_parts[] = { body_summary->get_satb_drain_seq(), body_summary->get_parallel_seq(), body_summary->get_clear_ct_seq() }; calc_other_times_ms = NumberSeq(summary->get_total_seq(), 3, other_parts); } else { // serial NumberSeq* other_parts[] = { body_summary->get_satb_drain_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_rs_seq(), body_summary->get_obj_copy_seq() }; calc_other_times_ms = NumberSeq(summary->get_total_seq(), 6, 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_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("EVACUATION PAUSES"); print_summary(_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 (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_region_num(bool young) { if (young) { ++_region_num_young; } else { ++_region_num_tenured; } } #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 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; }; } void G1CollectorPolicy::calculate_max_gc_locker_expansion() { size_t expansion_region_num = 0; if (GCLockerEdenExpansionPercent > 0) { double perc = (double) GCLockerEdenExpansionPercent / 100.0; double expansion_region_num_d = perc * (double) _young_list_target_length; // We use ceiling so that if expansion_region_num_d is > 0.0 (but // less than 1.0) we'll get 1. expansion_region_num = (size_t) ceil(expansion_region_num_d); } else { assert(expansion_region_num == 0, "sanity"); } _young_list_max_length = _young_list_target_length + expansion_region_num; assert(_young_list_target_length <= _young_list_max_length, "post-condition"); } // Calculates survivor space parameters. void G1CollectorPolicy::calculate_survivors_policy() { 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); } } #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 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle() { bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle(); if (!during_cycle) { set_initiate_conc_mark_if_possible(); return true; } else { return false; } } void G1CollectorPolicy::decide_on_conc_mark_initiation() { // We are about to decide on whether this pause will be an // initial-mark pause. // First, during_initial_mark_pause() should not be already set. We // will set it here if we have to. However, it should be cleared by // the end of the pause (it's only set for the duration of an // initial-mark pause). assert(!during_initial_mark_pause(), "pre-condition"); if (initiate_conc_mark_if_possible()) { // We had noticed on a previous pause that the heap occupancy has // gone over the initiating threshold and we should start a // concurrent marking cycle. So we might initiate one. bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle(); if (!during_cycle) { // The concurrent marking thread is not "during a cycle", i.e., // it has completed the last one. So we can go ahead and // initiate a new cycle. set_during_initial_mark_pause(); // And we can now clear initiate_conc_mark_if_possible() as // we've already acted on it. clear_initiate_conc_mark_if_possible(); } else { // The concurrent marking thread is still finishing up the // previous cycle. If we start one right now the two cycles // overlap. In particular, the concurrent marking thread might // be in the process of clearing the next marking bitmap (which // we will use for the next cycle if we start one). Starting a // cycle now will be bad given that parts of the marking // information might get cleared by the marking thread. And we // cannot wait for the marking thread to finish the cycle as it // periodically yields while clearing the next marking bitmap // and, if it's in a yield point, it's waiting for us to // finish. So, at this point we will not start a cycle and we'll // let the concurrent marking thread complete the last one. } } } 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 (G1CollectedHeap::use_parallel_gc_threads()) { const size_t OverpartitionFactor = 4; const size_t MinWorkUnit = 8; const size_t WorkUnit = MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor), MinWorkUnit); _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(), WorkUnit); ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser, (int) WorkUnit); _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 at the head of the non-incremental collection set void G1CollectorPolicy:: add_to_collection_set(HeapRegion* hr) { assert(_inc_cset_build_state == Active, "Precondition"); assert(!hr->is_young(), "non-incremental add of young region"); if (G1PrintHeapRegions) { gclog_or_tty->print_cr("added region to cset " "%d:["PTR_FORMAT", "PTR_FORMAT"], " "top "PTR_FORMAT", %s", hr->hrs_index(), hr->bottom(), hr->end(), hr->top(), hr->is_young() ? "YOUNG" : "NOT_YOUNG"); } 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); } // Initialize the per-collection-set information void G1CollectorPolicy::start_incremental_cset_building() { assert(_inc_cset_build_state == Inactive, "Precondition"); _inc_cset_head = NULL; _inc_cset_tail = NULL; _inc_cset_size = 0; _inc_cset_bytes_used_before = 0; if (in_young_gc_mode()) { _inc_cset_young_index = 0; } _inc_cset_max_finger = 0; _inc_cset_recorded_young_bytes = 0; _inc_cset_recorded_rs_lengths = 0; _inc_cset_predicted_elapsed_time_ms = 0; _inc_cset_predicted_bytes_to_copy = 0; _inc_cset_build_state = Active; } void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) { // This routine is used when: // * adding survivor regions to the incremental cset at the end of an // evacuation pause, // * adding the current allocation region to the incremental cset // when it is retired, and // * updating existing policy information for a region in the // incremental cset via young list RSet sampling. // Therefore this routine may be called at a safepoint by the // VM thread, or in-between safepoints by mutator threads (when // retiring the current allocation region) or a concurrent // refine thread (RSet sampling). double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true); size_t used_bytes = hr->used(); _inc_cset_recorded_rs_lengths += rs_length; _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms; _inc_cset_bytes_used_before += used_bytes; // Cache the values we have added to the aggregated informtion // in the heap region in case we have to remove this region from // the incremental collection set, or it is updated by the // rset sampling code hr->set_recorded_rs_length(rs_length); hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms); #if PREDICTIONS_VERBOSE size_t bytes_to_copy = predict_bytes_to_copy(hr); _inc_cset_predicted_bytes_to_copy += bytes_to_copy; // Record the number of bytes used in this region _inc_cset_recorded_young_bytes += used_bytes; // Cache the values we have added to the aggregated informtion // in the heap region in case we have to remove this region from // the incremental collection set, or it is updated by the // rset sampling code hr->set_predicted_bytes_to_copy(bytes_to_copy); #endif // PREDICTIONS_VERBOSE } void G1CollectorPolicy::remove_from_incremental_cset_info(HeapRegion* hr) { // This routine is currently only called as part of the updating of // existing policy information for regions in the incremental cset that // is performed by the concurrent refine thread(s) as part of young list // RSet sampling. Therefore we should not be at a safepoint. assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint"); assert(hr->is_young(), "it should be"); size_t used_bytes = hr->used(); size_t old_rs_length = hr->recorded_rs_length(); double old_elapsed_time_ms = hr->predicted_elapsed_time_ms(); // Subtract the old recorded/predicted policy information for // the given heap region from the collection set info. _inc_cset_recorded_rs_lengths -= old_rs_length; _inc_cset_predicted_elapsed_time_ms -= old_elapsed_time_ms; _inc_cset_bytes_used_before -= used_bytes; // Clear the values cached in the heap region hr->set_recorded_rs_length(0); hr->set_predicted_elapsed_time_ms(0); #if PREDICTIONS_VERBOSE size_t old_predicted_bytes_to_copy = hr->predicted_bytes_to_copy(); _inc_cset_predicted_bytes_to_copy -= old_predicted_bytes_to_copy; // Subtract the number of bytes used in this region _inc_cset_recorded_young_bytes -= used_bytes; // Clear the values cached in the heap region hr->set_predicted_bytes_to_copy(0); #endif // PREDICTIONS_VERBOSE } void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length) { // Update the collection set information that is dependent on the new RS length assert(hr->is_young(), "Precondition"); remove_from_incremental_cset_info(hr); add_to_incremental_cset_info(hr, new_rs_length); } void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) { assert( hr->is_young(), "invariant"); assert( hr->young_index_in_cset() == -1, "invariant" ); assert(_inc_cset_build_state == Active, "Precondition"); // We need to clear and set the cached recorded/cached collection set // information in the heap region here (before the region gets added // to the collection set). An individual heap region's cached values // are calculated, aggregated with the policy collection set info, // and cached in the heap region here (initially) and (subsequently) // by the Young List sampling code. size_t rs_length = hr->rem_set()->occupied(); add_to_incremental_cset_info(hr, rs_length); HeapWord* hr_end = hr->end(); _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end); assert(!hr->in_collection_set(), "invariant"); hr->set_in_collection_set(true); assert( hr->next_in_collection_set() == NULL, "invariant"); _inc_cset_size++; _g1->register_region_with_in_cset_fast_test(hr); hr->set_young_index_in_cset((int) _inc_cset_young_index); ++_inc_cset_young_index; } // Add the region at the RHS of the incremental cset void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) { // We should only ever be appending survivors at the end of a pause assert( hr->is_survivor(), "Logic"); // Do the 'common' stuff add_region_to_incremental_cset_common(hr); // Now add the region at the right hand side if (_inc_cset_tail == NULL) { assert(_inc_cset_head == NULL, "invariant"); _inc_cset_head = hr; } else { _inc_cset_tail->set_next_in_collection_set(hr); } _inc_cset_tail = hr; if (G1PrintHeapRegions) { gclog_or_tty->print_cr(" added region to incremental cset (RHS) " "%d:["PTR_FORMAT", "PTR_FORMAT"], " "top "PTR_FORMAT", young %s", hr->hrs_index(), hr->bottom(), hr->end(), hr->top(), (hr->is_young()) ? "YES" : "NO"); } } // Add the region to the LHS of the incremental cset void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) { // Survivors should be added to the RHS at the end of a pause assert(!hr->is_survivor(), "Logic"); // Do the 'common' stuff add_region_to_incremental_cset_common(hr); // Add the region at the left hand side hr->set_next_in_collection_set(_inc_cset_head); if (_inc_cset_head == NULL) { assert(_inc_cset_tail == NULL, "Invariant"); _inc_cset_tail = hr; } _inc_cset_head = hr; if (G1PrintHeapRegions) { gclog_or_tty->print_cr(" added region to incremental cset (LHS) " "%d:["PTR_FORMAT", "PTR_FORMAT"], " "top "PTR_FORMAT", young %s", hr->hrs_index(), hr->bottom(), hr->end(), hr->top(), (hr->is_young()) ? "YES" : "NO"); } } #ifndef PRODUCT void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) { assert(list_head == inc_cset_head() || list_head == collection_set(), "must be"); st->print_cr("\nCollection_set:"); HeapRegion* csr = list_head; while (csr != NULL) { HeapRegion* next = csr->next_in_collection_set(); assert(csr->in_collection_set(), "bad CS"); st->print_cr(" [%08x-%08x], t: %08x, P: %08x, N: %08x, C: %08x, " "age: %4d, y: %d, surv: %d", csr->bottom(), csr->end(), csr->top(), csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(), csr->top_at_conc_mark_count(), csr->age_in_surv_rate_group_cond(), csr->is_young(), csr->is_survivor()); csr = next; } } #endif // !PRODUCT void G1CollectorPolicy_BestRegionsFirst::choose_collection_set( double target_pause_time_ms) { // Set this here - in case we're not doing young collections. double non_young_start_time_sec = os::elapsedTime(); start_recording_regions(); guarantee(target_pause_time_ms > 0.0, err_msg("target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms)); guarantee(_collection_set == NULL, "Precondition"); double base_time_ms = predict_base_elapsed_time_ms(_pending_cards); double predicted_pause_time_ms = base_time_ms; double time_remaining_ms = target_pause_time_ms - base_time_ms; // the 10% and 50% values are arbitrary... if (time_remaining_ms < 0.10 * target_pause_time_ms) { time_remaining_ms = 0.50 * target_pause_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; _collection_set_bytes_used_before = 0; _collection_set_size = 0; // Adjust for expansion and slop. max_live_bytes = max_live_bytes + expansion_bytes; assert(_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; // The young list is laid with the survivor regions from the previous // pause are appended to the RHS of the young list, i.e. // [Newly Young Regions ++ Survivors from last pause]. hr = _g1->young_list()->first_survivor_region(); while (hr != NULL) { assert(hr->is_survivor(), "badly formed young list"); hr->set_young(); hr = hr->get_next_young_region(); } // Clear the fields that point to the survivor list - they are // all young now. _g1->young_list()->clear_survivors(); if (_g1->mark_in_progress()) _g1->concurrent_mark()->register_collection_set_finger(_inc_cset_max_finger); _young_cset_length = _inc_cset_young_index; _collection_set = _inc_cset_head; _collection_set_size = _inc_cset_size; _collection_set_bytes_used_before = _inc_cset_bytes_used_before; // For young regions in the collection set, we assume the worst // case of complete survival max_live_bytes -= _inc_cset_size * HeapRegion::GrainBytes; time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms; predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms; // The number of recorded young regions is the incremental // collection set's current size set_recorded_young_regions(_inc_cset_size); set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths); set_recorded_young_bytes(_inc_cset_recorded_young_bytes); #if PREDICTIONS_VERBOSE set_predicted_bytes_to_copy(_inc_cset_predicted_bytes_to_copy); #endif // PREDICTIONS_VERBOSE if (G1PolicyVerbose > 0) { gclog_or_tty->print_cr(" Added " PTR_FORMAT " Young Regions to CS.", _inc_cset_size); gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)", max_live_bytes/K); } assert(_inc_cset_size == _g1->young_list()->length(), "Invariant"); double young_end_time_sec = os::elapsedTime(); _recorded_young_cset_choice_time_ms = (young_end_time_sec - young_start_time_sec) * 1000.0; // We are doing young collections so reset this. non_young_start_time_sec = young_end_time_sec; // Note we can use either _collection_set_size or // _young_cset_length here if (_collection_set_size > 0 && _last_young_gc_full) { // don't bother adding more regions... goto choose_collection_set_end; } } 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) { 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_non_young_cset_region(hr); 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: stop_incremental_cset_building(); 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() { G1CollectorPolicy::record_collection_pause_end(); assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end."); }