--- a/src/hotspot/share/gc/g1/g1CollectedHeap.cpp Mon Mar 12 08:16:48 2018 +0100
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.cpp Mon Mar 12 09:46:12 2018 +0100
@@ -37,7 +37,6 @@
#include "gc/g1/g1CollectorState.hpp"
#include "gc/g1/g1ConcurrentRefine.hpp"
#include "gc/g1/g1ConcurrentRefineThread.hpp"
-#include "gc/g1/g1DefaultPolicy.hpp"
#include "gc/g1/g1EvacStats.inline.hpp"
#include "gc/g1/g1FullCollector.hpp"
#include "gc/g1/g1GCPhaseTimes.hpp"
@@ -1460,7 +1459,7 @@
_old_pool(NULL),
_gc_timer_stw(new (ResourceObj::C_HEAP, mtGC) STWGCTimer()),
_gc_tracer_stw(new (ResourceObj::C_HEAP, mtGC) G1NewTracer()),
- _g1_policy(new G1DefaultPolicy(_gc_timer_stw)),
+ _g1_policy(new G1Policy(_gc_timer_stw)),
_collection_set(this, _g1_policy),
_dirty_card_queue_set(false),
_is_alive_closure_cm(this),
--- a/src/hotspot/share/gc/g1/g1DefaultPolicy.cpp Mon Mar 12 08:16:48 2018 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,1165 +0,0 @@
-/*
- * Copyright (c) 2001, 2017, 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/g1/concurrentMarkThread.inline.hpp"
-#include "gc/g1/g1Analytics.hpp"
-#include "gc/g1/g1CollectedHeap.inline.hpp"
-#include "gc/g1/g1CollectionSet.hpp"
-#include "gc/g1/g1ConcurrentMark.hpp"
-#include "gc/g1/g1ConcurrentRefine.hpp"
-#include "gc/g1/g1DefaultPolicy.hpp"
-#include "gc/g1/g1HotCardCache.hpp"
-#include "gc/g1/g1IHOPControl.hpp"
-#include "gc/g1/g1GCPhaseTimes.hpp"
-#include "gc/g1/g1Policy.hpp"
-#include "gc/g1/g1SurvivorRegions.hpp"
-#include "gc/g1/g1YoungGenSizer.hpp"
-#include "gc/g1/heapRegion.inline.hpp"
-#include "gc/g1/heapRegionRemSet.hpp"
-#include "gc/shared/gcPolicyCounters.hpp"
-#include "logging/logStream.hpp"
-#include "runtime/arguments.hpp"
-#include "runtime/java.hpp"
-#include "runtime/mutexLocker.hpp"
-#include "utilities/debug.hpp"
-#include "utilities/growableArray.hpp"
-#include "utilities/pair.hpp"
-
-G1DefaultPolicy::G1DefaultPolicy(STWGCTimer* gc_timer) :
- _predictor(G1ConfidencePercent / 100.0),
- _analytics(new G1Analytics(&_predictor)),
- _mmu_tracker(new G1MMUTrackerQueue(GCPauseIntervalMillis / 1000.0, MaxGCPauseMillis / 1000.0)),
- _ihop_control(create_ihop_control(&_predictor)),
- _policy_counters(new GCPolicyCounters("GarbageFirst", 1, 2)),
- _young_list_fixed_length(0),
- _short_lived_surv_rate_group(new SurvRateGroup()),
- _survivor_surv_rate_group(new SurvRateGroup()),
- _reserve_factor((double) G1ReservePercent / 100.0),
- _reserve_regions(0),
- _rs_lengths_prediction(0),
- _bytes_allocated_in_old_since_last_gc(0),
- _initial_mark_to_mixed(),
- _collection_set(NULL),
- _g1(NULL),
- _phase_times(new G1GCPhaseTimes(gc_timer, ParallelGCThreads)),
- _tenuring_threshold(MaxTenuringThreshold),
- _max_survivor_regions(0),
- _survivors_age_table(true),
- _collection_pause_end_millis(os::javaTimeNanos() / NANOSECS_PER_MILLISEC) { }
-
-G1DefaultPolicy::~G1DefaultPolicy() {
- delete _ihop_control;
-}
-
-G1CollectorState* G1DefaultPolicy::collector_state() const { return _g1->collector_state(); }
-
-void G1DefaultPolicy::init(G1CollectedHeap* g1h, G1CollectionSet* collection_set) {
- _g1 = g1h;
- _collection_set = collection_set;
-
- assert(Heap_lock->owned_by_self(), "Locking discipline.");
-
- if (!adaptive_young_list_length()) {
- _young_list_fixed_length = _young_gen_sizer.min_desired_young_length();
- }
- _young_gen_sizer.adjust_max_new_size(_g1->max_regions());
-
- _free_regions_at_end_of_collection = _g1->num_free_regions();
-
- update_young_list_max_and_target_length();
- // We may immediately start allocating regions and placing them on the
- // collection set list. Initialize the per-collection set info
- _collection_set->start_incremental_building();
-}
-
-void G1DefaultPolicy::note_gc_start() {
- phase_times()->note_gc_start();
-}
-
-class G1YoungLengthPredictor VALUE_OBJ_CLASS_SPEC {
- const bool _during_cm;
- const double _base_time_ms;
- const double _base_free_regions;
- const double _target_pause_time_ms;
- const G1DefaultPolicy* const _policy;
-
- public:
- G1YoungLengthPredictor(bool during_cm,
- double base_time_ms,
- double base_free_regions,
- double target_pause_time_ms,
- const G1DefaultPolicy* policy) :
- _during_cm(during_cm),
- _base_time_ms(base_time_ms),
- _base_free_regions(base_free_regions),
- _target_pause_time_ms(target_pause_time_ms),
- _policy(policy) {}
-
- bool will_fit(uint young_length) const {
- if (young_length >= _base_free_regions) {
- // end condition 1: not enough space for the young regions
- return false;
- }
-
- const double accum_surv_rate = _policy->accum_yg_surv_rate_pred((int) young_length - 1);
- const size_t bytes_to_copy =
- (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
- const double copy_time_ms =
- _policy->analytics()->predict_object_copy_time_ms(bytes_to_copy, _during_cm);
- const double young_other_time_ms = _policy->analytics()->predict_young_other_time_ms(young_length);
- const 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: prediction is over the target pause time
- return false;
- }
-
- const size_t free_bytes = (_base_free_regions - young_length) * HeapRegion::GrainBytes;
-
- // When copying, we will likely need more bytes free than is live in the region.
- // Add some safety margin to factor in the confidence of our guess, and the
- // natural expected waste.
- // (100.0 / G1ConfidencePercent) is a scale factor that expresses the uncertainty
- // of the calculation: the lower the confidence, the more headroom.
- // (100 + TargetPLABWastePct) represents the increase in expected bytes during
- // copying due to anticipated waste in the PLABs.
- const double safety_factor = (100.0 / G1ConfidencePercent) * (100 + TargetPLABWastePct) / 100.0;
- const size_t expected_bytes_to_copy = (size_t)(safety_factor * bytes_to_copy);
-
- if (expected_bytes_to_copy > free_bytes) {
- // end condition 3: out-of-space
- return false;
- }
-
- // success!
- return true;
- }
-};
-
-void G1DefaultPolicy::record_new_heap_size(uint new_number_of_regions) {
- // re-calculate the necessary reserve
- double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
- // We use ceiling so that if reserve_regions_d is > 0.0 (but
- // smaller than 1.0) we'll get 1.
- _reserve_regions = (uint) ceil(reserve_regions_d);
-
- _young_gen_sizer.heap_size_changed(new_number_of_regions);
-
- _ihop_control->update_target_occupancy(new_number_of_regions * HeapRegion::GrainBytes);
-}
-
-uint G1DefaultPolicy::calculate_young_list_desired_min_length(uint base_min_length) const {
- uint desired_min_length = 0;
- if (adaptive_young_list_length()) {
- if (_analytics->num_alloc_rate_ms() > 3) {
- double now_sec = os::elapsedTime();
- double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
- double alloc_rate_ms = _analytics->predict_alloc_rate_ms();
- desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
- } else {
- // otherwise we don't have enough info to make the prediction
- }
- }
- desired_min_length += base_min_length;
- // make sure we don't go below any user-defined minimum bound
- return MAX2(_young_gen_sizer.min_desired_young_length(), desired_min_length);
-}
-
-uint G1DefaultPolicy::calculate_young_list_desired_max_length() const {
- // Here, we might want to also take into account any additional
- // constraints (i.e., user-defined minimum bound). Currently, we
- // effectively don't set this bound.
- return _young_gen_sizer.max_desired_young_length();
-}
-
-uint G1DefaultPolicy::update_young_list_max_and_target_length() {
- return update_young_list_max_and_target_length(_analytics->predict_rs_lengths());
-}
-
-uint G1DefaultPolicy::update_young_list_max_and_target_length(size_t rs_lengths) {
- uint unbounded_target_length = update_young_list_target_length(rs_lengths);
- update_max_gc_locker_expansion();
- return unbounded_target_length;
-}
-
-uint G1DefaultPolicy::update_young_list_target_length(size_t rs_lengths) {
- YoungTargetLengths young_lengths = young_list_target_lengths(rs_lengths);
- _young_list_target_length = young_lengths.first;
- return young_lengths.second;
-}
-
-G1DefaultPolicy::YoungTargetLengths G1DefaultPolicy::young_list_target_lengths(size_t rs_lengths) const {
- YoungTargetLengths result;
-
- // Calculate the absolute and desired min bounds first.
-
- // This is how many young regions we already have (currently: the survivors).
- const uint base_min_length = _g1->survivor_regions_count();
- uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
- // This is the absolute minimum young length. Ensure that we
- // will at least have one eden region available for allocation.
- uint absolute_min_length = base_min_length + MAX2(_g1->eden_regions_count(), (uint)1);
- // If we shrank the young list target it should not shrink below the current size.
- desired_min_length = MAX2(desired_min_length, absolute_min_length);
- // Calculate the absolute and desired max bounds.
-
- uint desired_max_length = calculate_young_list_desired_max_length();
-
- uint young_list_target_length = 0;
- if (adaptive_young_list_length()) {
- if (collector_state()->gcs_are_young()) {
- young_list_target_length =
- calculate_young_list_target_length(rs_lengths,
- base_min_length,
- desired_min_length,
- desired_max_length);
- } else {
- // Don't calculate anything and let the code below bound it to
- // the desired_min_length, i.e., do the next GC as soon as
- // possible to maximize how many old regions we can add to it.
- }
- } else {
- // The user asked for a fixed young gen so we'll fix the young gen
- // whether the next GC is young or mixed.
- young_list_target_length = _young_list_fixed_length;
- }
-
- result.second = young_list_target_length;
-
- // We will try our best not to "eat" into the reserve.
- uint absolute_max_length = 0;
- if (_free_regions_at_end_of_collection > _reserve_regions) {
- absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
- }
- if (desired_max_length > absolute_max_length) {
- desired_max_length = absolute_max_length;
- }
-
- // Make sure we don't go over the desired max length, nor under the
- // desired min length. In case they clash, desired_min_length wins
- // which is why that test is second.
- if (young_list_target_length > desired_max_length) {
- young_list_target_length = desired_max_length;
- }
- if (young_list_target_length < desired_min_length) {
- young_list_target_length = desired_min_length;
- }
-
- assert(young_list_target_length > base_min_length,
- "we should be able to allocate at least one eden region");
- assert(young_list_target_length >= absolute_min_length, "post-condition");
-
- result.first = young_list_target_length;
- return result;
-}
-
-uint
-G1DefaultPolicy::calculate_young_list_target_length(size_t rs_lengths,
- uint base_min_length,
- uint desired_min_length,
- uint desired_max_length) const {
- assert(adaptive_young_list_length(), "pre-condition");
- assert(collector_state()->gcs_are_young(), "only call this for young GCs");
-
- // In case some edge-condition makes the desired max length too small...
- if (desired_max_length <= desired_min_length) {
- return desired_min_length;
- }
-
- // We'll adjust min_young_length and max_young_length not to include
- // the already allocated young regions (i.e., so they reflect the
- // min and max eden regions we'll allocate). The base_min_length
- // will be reflected in the predictions by the
- // survivor_regions_evac_time prediction.
- assert(desired_min_length > base_min_length, "invariant");
- uint min_young_length = desired_min_length - base_min_length;
- assert(desired_max_length > base_min_length, "invariant");
- uint max_young_length = desired_max_length - base_min_length;
-
- const double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
- const double survivor_regions_evac_time = predict_survivor_regions_evac_time();
- const size_t pending_cards = _analytics->predict_pending_cards();
- const size_t adj_rs_lengths = rs_lengths + _analytics->predict_rs_length_diff();
- const size_t scanned_cards = _analytics->predict_card_num(adj_rs_lengths, /* gcs_are_young */ true);
- const double base_time_ms =
- predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
- survivor_regions_evac_time;
- const uint available_free_regions = _free_regions_at_end_of_collection;
- const uint base_free_regions =
- available_free_regions > _reserve_regions ? available_free_regions - _reserve_regions : 0;
-
- // Here, we will make sure that the shortest young length that
- // makes sense fits within the target pause time.
-
- G1YoungLengthPredictor p(collector_state()->during_concurrent_mark(),
- base_time_ms,
- base_free_regions,
- target_pause_time_ms,
- this);
- if (p.will_fit(min_young_length)) {
- // The shortest young length will fit into 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.
- if (p.will_fit(max_young_length)) {
- // The maximum young length will fit into the target pause time.
- // We are done so set min young length to the maximum length (as
- // the result is assumed to be returned in min_young_length).
- min_young_length = max_young_length;
- } else {
- // The maximum possible number of young regions will not fit within
- // the target pause time so we'll search for the optimal
- // length. The loop invariants are:
- //
- // min_young_length < max_young_length
- // min_young_length is known to fit into the target pause time
- // max_young_length is known not to fit into the target pause time
- //
- // Going into the loop we know the above hold as we've just
- // checked them. Every time around the loop we check whether
- // the middle value between min_young_length and
- // max_young_length fits into the target pause time. If it
- // does, it becomes the new min. If it doesn't, it becomes
- // the new max. This way we maintain the loop invariants.
-
- assert(min_young_length < max_young_length, "invariant");
- uint diff = (max_young_length - min_young_length) / 2;
- while (diff > 0) {
- uint young_length = min_young_length + diff;
- if (p.will_fit(young_length)) {
- min_young_length = young_length;
- } else {
- max_young_length = young_length;
- }
- assert(min_young_length < max_young_length, "invariant");
- diff = (max_young_length - min_young_length) / 2;
- }
- // The results is min_young_length which, according to the
- // loop invariants, should fit within the target pause time.
-
- // These are the post-conditions of the binary search above:
- assert(min_young_length < max_young_length,
- "otherwise we should have discovered that max_young_length "
- "fits into the pause target and not done the binary search");
- assert(p.will_fit(min_young_length),
- "min_young_length, the result of the binary search, should "
- "fit into the pause target");
- assert(!p.will_fit(min_young_length + 1),
- "min_young_length, the result of the binary search, should be "
- "optimal, so no larger length should fit into the pause target");
- }
- } else {
- // Even the minimum length doesn't fit into the pause time
- // target, return it as the result nevertheless.
- }
- return base_min_length + min_young_length;
-}
-
-double G1DefaultPolicy::predict_survivor_regions_evac_time() const {
- double survivor_regions_evac_time = 0.0;
- const GrowableArray<HeapRegion*>* survivor_regions = _g1->survivor()->regions();
-
- for (GrowableArrayIterator<HeapRegion*> it = survivor_regions->begin();
- it != survivor_regions->end();
- ++it) {
- survivor_regions_evac_time += predict_region_elapsed_time_ms(*it, collector_state()->gcs_are_young());
- }
- return survivor_regions_evac_time;
-}
-
-void G1DefaultPolicy::revise_young_list_target_length_if_necessary(size_t rs_lengths) {
- guarantee( adaptive_young_list_length(), "should not call this otherwise" );
-
- if (rs_lengths > _rs_lengths_prediction) {
- // add 10% to avoid having to recalculate often
- size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
- update_rs_lengths_prediction(rs_lengths_prediction);
-
- update_young_list_max_and_target_length(rs_lengths_prediction);
- }
-}
-
-void G1DefaultPolicy::update_rs_lengths_prediction() {
- update_rs_lengths_prediction(_analytics->predict_rs_lengths());
-}
-
-void G1DefaultPolicy::update_rs_lengths_prediction(size_t prediction) {
- if (collector_state()->gcs_are_young() && adaptive_young_list_length()) {
- _rs_lengths_prediction = prediction;
- }
-}
-
-void G1DefaultPolicy::record_full_collection_start() {
- _full_collection_start_sec = os::elapsedTime();
- // Release the future to-space so that it is available for compaction into.
- collector_state()->set_full_collection(true);
-}
-
-void G1DefaultPolicy::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 - _full_collection_start_sec;
- double full_gc_time_ms = full_gc_time_sec * 1000.0;
-
- _analytics->update_recent_gc_times(end_sec, full_gc_time_ms);
-
- collector_state()->set_full_collection(false);
-
- // "Nuke" the heuristics that control the young/mixed GC
- // transitions and make sure we start with young GCs after the Full GC.
- collector_state()->set_gcs_are_young(true);
- collector_state()->set_last_young_gc(false);
- collector_state()->set_initiate_conc_mark_if_possible(need_to_start_conc_mark("end of Full GC", 0));
- collector_state()->set_during_initial_mark_pause(false);
- collector_state()->set_in_marking_window(false);
- collector_state()->set_in_marking_window_im(false);
-
- _short_lived_surv_rate_group->start_adding_regions();
- // also call this on any additional surv rate groups
-
- _free_regions_at_end_of_collection = _g1->num_free_regions();
- // Reset survivors SurvRateGroup.
- _survivor_surv_rate_group->reset();
- update_young_list_max_and_target_length();
- update_rs_lengths_prediction();
- cset_chooser()->clear();
-
- _bytes_allocated_in_old_since_last_gc = 0;
-
- record_pause(FullGC, _full_collection_start_sec, end_sec);
-}
-
-void G1DefaultPolicy::record_collection_pause_start(double start_time_sec) {
- // We only need to do this here as the policy will only be applied
- // to the GC we're about to start. so, no point is calculating this
- // every time we calculate / recalculate the target young length.
- update_survivors_policy();
-
- assert(_g1->used() == _g1->recalculate_used(),
- "sanity, used: " SIZE_FORMAT " recalculate_used: " SIZE_FORMAT,
- _g1->used(), _g1->recalculate_used());
-
- phase_times()->record_cur_collection_start_sec(start_time_sec);
- _pending_cards = _g1->pending_card_num();
-
- _collection_set->reset_bytes_used_before();
- _bytes_copied_during_gc = 0;
-
- collector_state()->set_last_gc_was_young(false);
-
- // do that for any other surv rate groups
- _short_lived_surv_rate_group->stop_adding_regions();
- _survivors_age_table.clear();
-
- assert(_g1->collection_set()->verify_young_ages(), "region age verification failed");
-}
-
-void G1DefaultPolicy::record_concurrent_mark_init_end(double mark_init_elapsed_time_ms) {
- collector_state()->set_during_marking(true);
- assert(!collector_state()->initiate_conc_mark_if_possible(), "we should have cleared it by now");
- collector_state()->set_during_initial_mark_pause(false);
-}
-
-void G1DefaultPolicy::record_concurrent_mark_remark_start() {
- _mark_remark_start_sec = os::elapsedTime();
- collector_state()->set_during_marking(false);
-}
-
-void G1DefaultPolicy::record_concurrent_mark_remark_end() {
- double end_time_sec = os::elapsedTime();
- double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
- _analytics->report_concurrent_mark_remark_times_ms(elapsed_time_ms);
- _analytics->append_prev_collection_pause_end_ms(elapsed_time_ms);
-
- record_pause(Remark, _mark_remark_start_sec, end_time_sec);
-}
-
-void G1DefaultPolicy::record_concurrent_mark_cleanup_start() {
- _mark_cleanup_start_sec = os::elapsedTime();
-}
-
-void G1DefaultPolicy::record_concurrent_mark_cleanup_completed() {
- bool should_continue_with_reclaim = next_gc_should_be_mixed("request last young-only gc",
- "skip last young-only gc");
- collector_state()->set_last_young_gc(should_continue_with_reclaim);
- // We skip the marking phase.
- if (!should_continue_with_reclaim) {
- abort_time_to_mixed_tracking();
- }
- collector_state()->set_in_marking_window(false);
-}
-
-double G1DefaultPolicy::average_time_ms(G1GCPhaseTimes::GCParPhases phase) const {
- return phase_times()->average_time_ms(phase);
-}
-
-double G1DefaultPolicy::young_other_time_ms() const {
- return phase_times()->young_cset_choice_time_ms() +
- phase_times()->average_time_ms(G1GCPhaseTimes::YoungFreeCSet);
-}
-
-double G1DefaultPolicy::non_young_other_time_ms() const {
- return phase_times()->non_young_cset_choice_time_ms() +
- phase_times()->average_time_ms(G1GCPhaseTimes::NonYoungFreeCSet);
-}
-
-double G1DefaultPolicy::other_time_ms(double pause_time_ms) const {
- return pause_time_ms - phase_times()->cur_collection_par_time_ms();
-}
-
-double G1DefaultPolicy::constant_other_time_ms(double pause_time_ms) const {
- return other_time_ms(pause_time_ms) - phase_times()->total_free_cset_time_ms();
-}
-
-CollectionSetChooser* G1DefaultPolicy::cset_chooser() const {
- return _collection_set->cset_chooser();
-}
-
-bool G1DefaultPolicy::about_to_start_mixed_phase() const {
- return _g1->concurrent_mark()->cm_thread()->during_cycle() || collector_state()->last_young_gc();
-}
-
-bool G1DefaultPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
- if (about_to_start_mixed_phase()) {
- return false;
- }
-
- size_t marking_initiating_used_threshold = _ihop_control->get_conc_mark_start_threshold();
-
- size_t cur_used_bytes = _g1->non_young_capacity_bytes();
- size_t alloc_byte_size = alloc_word_size * HeapWordSize;
- size_t marking_request_bytes = cur_used_bytes + alloc_byte_size;
-
- bool result = false;
- if (marking_request_bytes > marking_initiating_used_threshold) {
- result = collector_state()->gcs_are_young() && !collector_state()->last_young_gc();
- log_debug(gc, ergo, ihop)("%s occupancy: " SIZE_FORMAT "B allocation request: " SIZE_FORMAT "B threshold: " SIZE_FORMAT "B (%1.2f) source: %s",
- result ? "Request concurrent cycle initiation (occupancy higher than threshold)" : "Do not request concurrent cycle initiation (still doing mixed collections)",
- cur_used_bytes, alloc_byte_size, marking_initiating_used_threshold, (double) marking_initiating_used_threshold / _g1->capacity() * 100, source);
- }
-
- return result;
-}
-
-// Anything below that is considered to be zero
-#define MIN_TIMER_GRANULARITY 0.0000001
-
-void G1DefaultPolicy::record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc) {
- double end_time_sec = os::elapsedTime();
-
- 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();
-
- record_pause(young_gc_pause_kind(), end_time_sec - pause_time_ms / 1000.0, end_time_sec);
-
- _collection_pause_end_millis = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
-
- last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
- if (last_pause_included_initial_mark) {
- record_concurrent_mark_init_end(0.0);
- } else {
- maybe_start_marking();
- }
-
- double app_time_ms = (phase_times()->cur_collection_start_sec() * 1000.0 - _analytics->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;
- }
-
- if (update_stats) {
- // We maintain the invariant that all objects allocated by mutator
- // threads will be allocated out of eden regions. So, we can use
- // the eden region number allocated since the previous GC to
- // calculate the application's allocate rate. The only exception
- // to that is humongous objects that are allocated separately. But
- // given that humongous object allocations do not really affect
- // either the pause's duration nor when the next pause will take
- // place we can safely ignore them here.
- uint regions_allocated = _collection_set->eden_region_length();
- double alloc_rate_ms = (double) regions_allocated / app_time_ms;
- _analytics->report_alloc_rate_ms(alloc_rate_ms);
-
- double interval_ms =
- (end_time_sec - _analytics->last_known_gc_end_time_sec()) * 1000.0;
- _analytics->update_recent_gc_times(end_time_sec, pause_time_ms);
- _analytics->compute_pause_time_ratio(interval_ms, pause_time_ms);
- }
-
- bool new_in_marking_window = collector_state()->in_marking_window();
- bool new_in_marking_window_im = false;
- if (last_pause_included_initial_mark) {
- new_in_marking_window = true;
- new_in_marking_window_im = true;
- }
-
- if (collector_state()->last_young_gc()) {
- // This is supposed to to be the "last young GC" before we start
- // doing mixed GCs. Here we decide whether to start mixed GCs or not.
- assert(!last_pause_included_initial_mark, "The last young GC is not allowed to be an initial mark GC");
-
- if (next_gc_should_be_mixed("start mixed GCs",
- "do not start mixed GCs")) {
- collector_state()->set_gcs_are_young(false);
- } else {
- // We aborted the mixed GC phase early.
- abort_time_to_mixed_tracking();
- }
-
- collector_state()->set_last_young_gc(false);
- }
-
- if (!collector_state()->last_gc_was_young()) {
- // This is a mixed GC. Here we decide whether to continue doing
- // mixed GCs or not.
- if (!next_gc_should_be_mixed("continue mixed GCs",
- "do not continue mixed GCs")) {
- collector_state()->set_gcs_are_young(true);
-
- maybe_start_marking();
- }
- }
-
- _short_lived_surv_rate_group->start_adding_regions();
- // Do that for any other surv rate groups
-
- double scan_hcc_time_ms = G1HotCardCache::default_use_cache() ? average_time_ms(G1GCPhaseTimes::ScanHCC) : 0.0;
-
- if (update_stats) {
- double cost_per_card_ms = 0.0;
- if (_pending_cards > 0) {
- cost_per_card_ms = (average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms) / (double) _pending_cards;
- _analytics->report_cost_per_card_ms(cost_per_card_ms);
- }
- _analytics->report_cost_scan_hcc(scan_hcc_time_ms);
-
- double cost_per_entry_ms = 0.0;
- if (cards_scanned > 10) {
- cost_per_entry_ms = average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
- _analytics->report_cost_per_entry_ms(cost_per_entry_ms, collector_state()->last_gc_was_young());
- }
-
- if (_max_rs_lengths > 0) {
- double cards_per_entry_ratio =
- (double) cards_scanned / (double) _max_rs_lengths;
- _analytics->report_cards_per_entry_ratio(cards_per_entry_ratio, collector_state()->last_gc_was_young());
- }
-
- // This is defensive. For a while _max_rs_lengths could get
- // smaller than _recorded_rs_lengths which was causing
- // rs_length_diff to get very large and mess up the RSet length
- // predictions. The reason was unsafe concurrent updates to the
- // _inc_cset_recorded_rs_lengths field which the code below guards
- // against (see CR 7118202). This bug has now been fixed (see CR
- // 7119027). However, I'm still worried that
- // _inc_cset_recorded_rs_lengths might still end up somewhat
- // inaccurate. The concurrent refinement thread calculates an
- // RSet's length concurrently with other CR threads updating it
- // which might cause it to calculate the length incorrectly (if,
- // say, it's in mid-coarsening). So I'll leave in the defensive
- // conditional below just in case.
- size_t rs_length_diff = 0;
- size_t recorded_rs_lengths = _collection_set->recorded_rs_lengths();
- if (_max_rs_lengths > recorded_rs_lengths) {
- rs_length_diff = _max_rs_lengths - recorded_rs_lengths;
- }
- _analytics->report_rs_length_diff((double) rs_length_diff);
-
- size_t freed_bytes = heap_used_bytes_before_gc - cur_used_bytes;
- size_t copied_bytes = _collection_set->bytes_used_before() - freed_bytes;
- double cost_per_byte_ms = 0.0;
-
- if (copied_bytes > 0) {
- cost_per_byte_ms = average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
- _analytics->report_cost_per_byte_ms(cost_per_byte_ms, collector_state()->in_marking_window());
- }
-
- if (_collection_set->young_region_length() > 0) {
- _analytics->report_young_other_cost_per_region_ms(young_other_time_ms() /
- _collection_set->young_region_length());
- }
-
- if (_collection_set->old_region_length() > 0) {
- _analytics->report_non_young_other_cost_per_region_ms(non_young_other_time_ms() /
- _collection_set->old_region_length());
- }
-
- _analytics->report_constant_other_time_ms(constant_other_time_ms(pause_time_ms));
-
- _analytics->report_pending_cards((double) _pending_cards);
- _analytics->report_rs_lengths((double) _max_rs_lengths);
- }
-
- collector_state()->set_in_marking_window(new_in_marking_window);
- collector_state()->set_in_marking_window_im(new_in_marking_window_im);
- _free_regions_at_end_of_collection = _g1->num_free_regions();
- // IHOP control wants to know the expected young gen length if it were not
- // restrained by the heap reserve. Using the actual length would make the
- // prediction too small and the limit the young gen every time we get to the
- // predicted target occupancy.
- size_t last_unrestrained_young_length = update_young_list_max_and_target_length();
- update_rs_lengths_prediction();
-
- update_ihop_prediction(app_time_ms / 1000.0,
- _bytes_allocated_in_old_since_last_gc,
- last_unrestrained_young_length * HeapRegion::GrainBytes);
- _bytes_allocated_in_old_since_last_gc = 0;
-
- _ihop_control->send_trace_event(_g1->gc_tracer_stw());
-
- // 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;
-
- if (update_rs_time_goal_ms < scan_hcc_time_ms) {
- log_debug(gc, ergo, refine)("Adjust concurrent refinement thresholds (scanning the HCC expected to take longer than Update RS time goal)."
- "Update RS time goal: %1.2fms Scan HCC time: %1.2fms",
- update_rs_time_goal_ms, scan_hcc_time_ms);
-
- update_rs_time_goal_ms = 0;
- } else {
- update_rs_time_goal_ms -= scan_hcc_time_ms;
- }
- _g1->concurrent_refine()->adjust(average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms,
- phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS),
- update_rs_time_goal_ms);
-
- cset_chooser()->verify();
-}
-
-G1IHOPControl* G1DefaultPolicy::create_ihop_control(const G1Predictions* predictor){
- if (G1UseAdaptiveIHOP) {
- return new G1AdaptiveIHOPControl(InitiatingHeapOccupancyPercent,
- predictor,
- G1ReservePercent,
- G1HeapWastePercent);
- } else {
- return new G1StaticIHOPControl(InitiatingHeapOccupancyPercent);
- }
-}
-
-void G1DefaultPolicy::update_ihop_prediction(double mutator_time_s,
- size_t mutator_alloc_bytes,
- size_t young_gen_size) {
- // Always try to update IHOP prediction. Even evacuation failures give information
- // about e.g. whether to start IHOP earlier next time.
-
- // Avoid using really small application times that might create samples with
- // very high or very low values. They may be caused by e.g. back-to-back gcs.
- double const min_valid_time = 1e-6;
-
- bool report = false;
-
- double marking_to_mixed_time = -1.0;
- if (!collector_state()->last_gc_was_young() && _initial_mark_to_mixed.has_result()) {
- marking_to_mixed_time = _initial_mark_to_mixed.last_marking_time();
- assert(marking_to_mixed_time > 0.0,
- "Initial mark to mixed time must be larger than zero but is %.3f",
- marking_to_mixed_time);
- if (marking_to_mixed_time > min_valid_time) {
- _ihop_control->update_marking_length(marking_to_mixed_time);
- report = true;
- }
- }
-
- // As an approximation for the young gc promotion rates during marking we use
- // all of them. In many applications there are only a few if any young gcs during
- // marking, which makes any prediction useless. This increases the accuracy of the
- // prediction.
- if (collector_state()->last_gc_was_young() && mutator_time_s > min_valid_time) {
- _ihop_control->update_allocation_info(mutator_time_s, mutator_alloc_bytes, young_gen_size);
- report = true;
- }
-
- if (report) {
- report_ihop_statistics();
- }
-}
-
-void G1DefaultPolicy::report_ihop_statistics() {
- _ihop_control->print();
-}
-
-void G1DefaultPolicy::print_phases() {
- phase_times()->print();
-}
-
-double G1DefaultPolicy::predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const {
- TruncatedSeq* seq = surv_rate_group->get_seq(age);
- guarantee(seq->num() > 0, "There should be some young gen survivor samples available. Tried to access with age %d", age);
- double pred = _predictor.get_new_prediction(seq);
- if (pred > 1.0) {
- pred = 1.0;
- }
- return pred;
-}
-
-double G1DefaultPolicy::accum_yg_surv_rate_pred(int age) const {
- return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
-}
-
-double G1DefaultPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
- size_t scanned_cards) const {
- return
- _analytics->predict_rs_update_time_ms(pending_cards) +
- _analytics->predict_rs_scan_time_ms(scanned_cards, collector_state()->gcs_are_young()) +
- _analytics->predict_constant_other_time_ms();
-}
-
-double G1DefaultPolicy::predict_base_elapsed_time_ms(size_t pending_cards) const {
- size_t rs_length = _analytics->predict_rs_lengths() + _analytics->predict_rs_length_diff();
- size_t card_num = _analytics->predict_card_num(rs_length, collector_state()->gcs_are_young());
- return predict_base_elapsed_time_ms(pending_cards, card_num);
-}
-
-size_t G1DefaultPolicy::predict_bytes_to_copy(HeapRegion* hr) const {
- size_t bytes_to_copy;
- if (hr->is_marked())
- bytes_to_copy = hr->max_live_bytes();
- else {
- assert(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) (hr->used() * yg_surv_rate);
- }
- return bytes_to_copy;
-}
-
-double G1DefaultPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
- bool for_young_gc) const {
- size_t rs_length = hr->rem_set()->occupied();
- // Predicting the number of cards is based on which type of GC
- // we're predicting for.
- size_t card_num = _analytics->predict_card_num(rs_length, for_young_gc);
- size_t bytes_to_copy = predict_bytes_to_copy(hr);
-
- double region_elapsed_time_ms =
- _analytics->predict_rs_scan_time_ms(card_num, collector_state()->gcs_are_young()) +
- _analytics->predict_object_copy_time_ms(bytes_to_copy, collector_state()->during_concurrent_mark());
-
- // The prediction of the "other" time for this region is based
- // upon the region type and NOT the GC type.
- if (hr->is_young()) {
- region_elapsed_time_ms += _analytics->predict_young_other_time_ms(1);
- } else {
- region_elapsed_time_ms += _analytics->predict_non_young_other_time_ms(1);
- }
- return region_elapsed_time_ms;
-}
-
-bool G1DefaultPolicy::should_allocate_mutator_region() const {
- uint young_list_length = _g1->young_regions_count();
- uint young_list_target_length = _young_list_target_length;
- return young_list_length < young_list_target_length;
-}
-
-bool G1DefaultPolicy::can_expand_young_list() const {
- uint young_list_length = _g1->young_regions_count();
- uint young_list_max_length = _young_list_max_length;
- return young_list_length < young_list_max_length;
-}
-
-bool G1DefaultPolicy::adaptive_young_list_length() const {
- return _young_gen_sizer.adaptive_young_list_length();
-}
-
-size_t G1DefaultPolicy::desired_survivor_size() const {
- size_t const survivor_capacity = HeapRegion::GrainWords * _max_survivor_regions;
- return (size_t)((((double)survivor_capacity) * TargetSurvivorRatio) / 100);
-}
-
-void G1DefaultPolicy::print_age_table() {
- _survivors_age_table.print_age_table(_tenuring_threshold);
-}
-
-void G1DefaultPolicy::update_max_gc_locker_expansion() {
- uint 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 = (uint) 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 G1DefaultPolicy::update_survivors_policy() {
- double max_survivor_regions_d =
- (double) _young_list_target_length / (double) SurvivorRatio;
- // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
- // smaller than 1.0) we'll get 1.
- _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
-
- _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(desired_survivor_size());
- if (UsePerfData) {
- _policy_counters->tenuring_threshold()->set_value(_tenuring_threshold);
- _policy_counters->desired_survivor_size()->set_value(desired_survivor_size() * oopSize);
- }
-}
-
-bool G1DefaultPolicy::force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause) {
- // We actually check whether we are marking here and not if we are in a
- // reclamation phase. This means that we will schedule a concurrent mark
- // even while we are still in the process of reclaiming memory.
- bool during_cycle = _g1->concurrent_mark()->cm_thread()->during_cycle();
- if (!during_cycle) {
- log_debug(gc, ergo)("Request concurrent cycle initiation (requested by GC cause). GC cause: %s", GCCause::to_string(gc_cause));
- collector_state()->set_initiate_conc_mark_if_possible(true);
- return true;
- } else {
- log_debug(gc, ergo)("Do not request concurrent cycle initiation (concurrent cycle already in progress). GC cause: %s", GCCause::to_string(gc_cause));
- return false;
- }
-}
-
-void G1DefaultPolicy::initiate_conc_mark() {
- collector_state()->set_during_initial_mark_pause(true);
- collector_state()->set_initiate_conc_mark_if_possible(false);
-}
-
-void G1DefaultPolicy::decide_on_conc_mark_initiation() {
- // We are about to decide on whether this pause will be an
- // initial-mark pause.
-
- // First, collector_state()->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(!collector_state()->during_initial_mark_pause(), "pre-condition");
-
- if (collector_state()->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.
-
- if (!about_to_start_mixed_phase() && collector_state()->gcs_are_young()) {
- // Initiate a new initial mark if there is no marking or reclamation going on.
- initiate_conc_mark();
- log_debug(gc, ergo)("Initiate concurrent cycle (concurrent cycle initiation requested)");
- } else if (_g1->is_user_requested_concurrent_full_gc(_g1->gc_cause())) {
- // Initiate a user requested initial mark. An initial mark must be young only
- // GC, so the collector state must be updated to reflect this.
- collector_state()->set_gcs_are_young(true);
- collector_state()->set_last_young_gc(false);
-
- abort_time_to_mixed_tracking();
- initiate_conc_mark();
- log_debug(gc, ergo)("Initiate concurrent cycle (user requested concurrent cycle)");
- } 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.
- log_debug(gc, ergo)("Do not initiate concurrent cycle (concurrent cycle already in progress)");
- }
- }
-}
-
-void G1DefaultPolicy::record_concurrent_mark_cleanup_end() {
- cset_chooser()->rebuild(_g1->workers(), _g1->num_regions());
-
- double end_sec = os::elapsedTime();
- double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
- _analytics->report_concurrent_mark_cleanup_times_ms(elapsed_time_ms);
- _analytics->append_prev_collection_pause_end_ms(elapsed_time_ms);
-
- record_pause(Cleanup, _mark_cleanup_start_sec, end_sec);
-}
-
-double G1DefaultPolicy::reclaimable_bytes_percent(size_t reclaimable_bytes) const {
- return percent_of(reclaimable_bytes, _g1->capacity());
-}
-
-void G1DefaultPolicy::maybe_start_marking() {
- if (need_to_start_conc_mark("end of GC")) {
- // 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.
- collector_state()->set_initiate_conc_mark_if_possible(true);
- }
-}
-
-G1DefaultPolicy::PauseKind G1DefaultPolicy::young_gc_pause_kind() const {
- assert(!collector_state()->full_collection(), "must be");
- if (collector_state()->during_initial_mark_pause()) {
- assert(collector_state()->last_gc_was_young(), "must be");
- assert(!collector_state()->last_young_gc(), "must be");
- return InitialMarkGC;
- } else if (collector_state()->last_young_gc()) {
- assert(!collector_state()->during_initial_mark_pause(), "must be");
- assert(collector_state()->last_gc_was_young(), "must be");
- return LastYoungGC;
- } else if (!collector_state()->last_gc_was_young()) {
- assert(!collector_state()->during_initial_mark_pause(), "must be");
- assert(!collector_state()->last_young_gc(), "must be");
- return MixedGC;
- } else {
- assert(collector_state()->last_gc_was_young(), "must be");
- assert(!collector_state()->during_initial_mark_pause(), "must be");
- assert(!collector_state()->last_young_gc(), "must be");
- return YoungOnlyGC;
- }
-}
-
-void G1DefaultPolicy::record_pause(PauseKind kind, double start, double end) {
- // Manage the MMU tracker. For some reason it ignores Full GCs.
- if (kind != FullGC) {
- _mmu_tracker->add_pause(start, end);
- }
- // Manage the mutator time tracking from initial mark to first mixed gc.
- switch (kind) {
- case FullGC:
- abort_time_to_mixed_tracking();
- break;
- case Cleanup:
- case Remark:
- case YoungOnlyGC:
- case LastYoungGC:
- _initial_mark_to_mixed.add_pause(end - start);
- break;
- case InitialMarkGC:
- _initial_mark_to_mixed.record_initial_mark_end(end);
- break;
- case MixedGC:
- _initial_mark_to_mixed.record_mixed_gc_start(start);
- break;
- default:
- ShouldNotReachHere();
- }
-}
-
-void G1DefaultPolicy::abort_time_to_mixed_tracking() {
- _initial_mark_to_mixed.reset();
-}
-
-bool G1DefaultPolicy::next_gc_should_be_mixed(const char* true_action_str,
- const char* false_action_str) const {
- if (cset_chooser()->is_empty()) {
- log_debug(gc, ergo)("%s (candidate old regions not available)", false_action_str);
- return false;
- }
-
- // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
- size_t reclaimable_bytes = cset_chooser()->remaining_reclaimable_bytes();
- double reclaimable_percent = reclaimable_bytes_percent(reclaimable_bytes);
- double threshold = (double) G1HeapWastePercent;
- if (reclaimable_percent <= threshold) {
- log_debug(gc, ergo)("%s (reclaimable percentage not over threshold). candidate old regions: %u reclaimable: " SIZE_FORMAT " (%1.2f) threshold: " UINTX_FORMAT,
- false_action_str, cset_chooser()->remaining_regions(), reclaimable_bytes, reclaimable_percent, G1HeapWastePercent);
- return false;
- }
- log_debug(gc, ergo)("%s (candidate old regions available). candidate old regions: %u reclaimable: " SIZE_FORMAT " (%1.2f) threshold: " UINTX_FORMAT,
- true_action_str, cset_chooser()->remaining_regions(), reclaimable_bytes, reclaimable_percent, G1HeapWastePercent);
- return true;
-}
-
-uint G1DefaultPolicy::calc_min_old_cset_length() const {
- // The min old CSet region bound is based on the maximum desired
- // number of mixed GCs after a cycle. I.e., even if some old regions
- // look expensive, we should add them to the CSet anyway to make
- // sure we go through the available old regions in no more than the
- // maximum desired number of mixed GCs.
- //
- // The calculation is based on the number of marked regions we added
- // to the CSet chooser in the first place, not how many remain, so
- // that the result is the same during all mixed GCs that follow a cycle.
-
- const size_t region_num = (size_t) cset_chooser()->length();
- const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
- size_t result = region_num / gc_num;
- // emulate ceiling
- if (result * gc_num < region_num) {
- result += 1;
- }
- return (uint) result;
-}
-
-uint G1DefaultPolicy::calc_max_old_cset_length() const {
- // The max old CSet region bound is based on the threshold expressed
- // as a percentage of the heap size. I.e., it should bound the
- // number of old regions added to the CSet irrespective of how many
- // of them are available.
-
- const G1CollectedHeap* g1h = G1CollectedHeap::heap();
- const size_t region_num = g1h->num_regions();
- const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
- size_t result = region_num * perc / 100;
- // emulate ceiling
- if (100 * result < region_num * perc) {
- result += 1;
- }
- return (uint) result;
-}
-
-void G1DefaultPolicy::finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor) {
- double time_remaining_ms = _collection_set->finalize_young_part(target_pause_time_ms, survivor);
- _collection_set->finalize_old_part(time_remaining_ms);
-}
-
-void G1DefaultPolicy::transfer_survivors_to_cset(const G1SurvivorRegions* survivors) {
-
- // Add survivor regions to SurvRateGroup.
- note_start_adding_survivor_regions();
- finished_recalculating_age_indexes(true /* is_survivors */);
-
- HeapRegion* last = NULL;
- for (GrowableArrayIterator<HeapRegion*> it = survivors->regions()->begin();
- it != survivors->regions()->end();
- ++it) {
- HeapRegion* curr = *it;
- set_region_survivor(curr);
-
- // The region is a non-empty survivor so let's add it to
- // the incremental collection set for the next evacuation
- // pause.
- _collection_set->add_survivor_regions(curr);
-
- last = curr;
- }
- note_stop_adding_survivor_regions();
-
- // Don't clear the survivor list handles until the start of
- // the next evacuation pause - we need it in order to re-tag
- // the survivor regions from this evacuation pause as 'young'
- // at the start of the next.
-
- finished_recalculating_age_indexes(false /* is_survivors */);
-}
--- a/src/hotspot/share/gc/g1/g1DefaultPolicy.hpp Mon Mar 12 08:16:48 2018 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,399 +0,0 @@
-/*
- * Copyright (c) 2016, 2017, 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.
- *
- */
-
-#ifndef SHARE_VM_GC_G1_G1DEFAULTPOLICY_HPP
-#define SHARE_VM_GC_G1_G1DEFAULTPOLICY_HPP
-
-#include "gc/g1/g1CollectorState.hpp"
-#include "gc/g1/g1GCPhaseTimes.hpp"
-#include "gc/g1/g1InCSetState.hpp"
-#include "gc/g1/g1InitialMarkToMixedTimeTracker.hpp"
-#include "gc/g1/g1MMUTracker.hpp"
-#include "gc/g1/g1Predictions.hpp"
-#include "gc/g1/g1Policy.hpp"
-#include "gc/g1/g1YoungGenSizer.hpp"
-#include "gc/shared/gcCause.hpp"
-#include "utilities/pair.hpp"
-
-class HeapRegion;
-class G1CollectionSet;
-class CollectionSetChooser;
-class G1IHOPControl;
-class G1Analytics;
-class G1SurvivorRegions;
-class G1YoungGenSizer;
-class GCPolicyCounters;
-class STWGCTimer;
-
-class G1DefaultPolicy: public G1Policy {
- private:
-
- static G1IHOPControl* create_ihop_control(const G1Predictions* predictor);
- // Update the IHOP control with necessary statistics.
- void update_ihop_prediction(double mutator_time_s,
- size_t mutator_alloc_bytes,
- size_t young_gen_size);
- void report_ihop_statistics();
-
- G1Predictions _predictor;
- G1Analytics* _analytics;
- G1MMUTracker* _mmu_tracker;
- G1IHOPControl* _ihop_control;
-
- GCPolicyCounters* _policy_counters;
-
- double _full_collection_start_sec;
-
- jlong _collection_pause_end_millis;
-
- uint _young_list_target_length;
- uint _young_list_fixed_length;
-
- // The max number of regions we can extend the eden by while the GC
- // locker is active. This should be >= _young_list_target_length;
- uint _young_list_max_length;
-
- // SurvRateGroups below must be initialized after the predictor because they
- // indirectly use it through this object passed to their constructor.
- SurvRateGroup* _short_lived_surv_rate_group;
- SurvRateGroup* _survivor_surv_rate_group;
-
- double _reserve_factor;
- // This will be set when the heap is expanded
- // for the first time during initialization.
- uint _reserve_regions;
-
- G1YoungGenSizer _young_gen_sizer;
-
- uint _free_regions_at_end_of_collection;
-
- size_t _max_rs_lengths;
-
- size_t _rs_lengths_prediction;
-
- size_t _pending_cards;
-
- // The amount of allocated bytes in old gen during the last mutator and the following
- // young GC phase.
- size_t _bytes_allocated_in_old_since_last_gc;
-
- G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
-public:
- const G1Predictions& predictor() const { return _predictor; }
- const G1Analytics* analytics() const { return const_cast<const G1Analytics*>(_analytics); }
-
- void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; }
-
- void set_region_eden(HeapRegion* hr) {
- hr->set_eden();
- hr->install_surv_rate_group(_short_lived_surv_rate_group);
- }
-
- void set_region_survivor(HeapRegion* hr) {
- assert(hr->is_survivor(), "pre-condition");
- hr->install_surv_rate_group(_survivor_surv_rate_group);
- }
-
- void record_max_rs_lengths(size_t rs_lengths) {
- _max_rs_lengths = rs_lengths;
- }
-
-
- double predict_base_elapsed_time_ms(size_t pending_cards) const;
- double predict_base_elapsed_time_ms(size_t pending_cards,
- size_t scanned_cards) const;
- size_t predict_bytes_to_copy(HeapRegion* hr) const;
- double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
-
- double predict_survivor_regions_evac_time() const;
-
- bool should_update_surv_rate_group_predictors() {
- return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
- }
-
- void cset_regions_freed() {
- bool update = should_update_surv_rate_group_predictors();
-
- _short_lived_surv_rate_group->all_surviving_words_recorded(predictor(), update);
- _survivor_surv_rate_group->all_surviving_words_recorded(predictor(), update);
- }
-
- G1MMUTracker* mmu_tracker() {
- return _mmu_tracker;
- }
-
- const G1MMUTracker* mmu_tracker() const {
- return _mmu_tracker;
- }
-
- double max_pause_time_ms() const {
- return _mmu_tracker->max_gc_time() * 1000.0;
- }
-
- double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
-
- double predict_yg_surv_rate(int age) const;
-
- double accum_yg_surv_rate_pred(int age) const;
-
-protected:
- G1CollectionSet* _collection_set;
- virtual double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
- virtual double other_time_ms(double pause_time_ms) const;
-
- double young_other_time_ms() const;
- double non_young_other_time_ms() const;
- double constant_other_time_ms(double pause_time_ms) const;
-
- CollectionSetChooser* cset_chooser() const;
-private:
-
- // The number of bytes copied during the GC.
- size_t _bytes_copied_during_gc;
-
- // Stash a pointer to the g1 heap.
- G1CollectedHeap* _g1;
-
- G1GCPhaseTimes* _phase_times;
-
- // This set of variables tracks the collector efficiency, in order to
- // determine whether we should initiate a new marking.
- double _mark_remark_start_sec;
- double _mark_cleanup_start_sec;
-
- // Updates the internal young list maximum and target lengths. Returns the
- // unbounded young list target length.
- uint update_young_list_max_and_target_length();
- uint update_young_list_max_and_target_length(size_t rs_lengths);
-
- // Update the young list target length either by setting it to the
- // desired fixed value or by calculating it using G1's pause
- // prediction model. If no rs_lengths parameter is passed, predict
- // the RS lengths using the prediction model, otherwise use the
- // given rs_lengths as the prediction.
- // Returns the unbounded young list target length.
- uint update_young_list_target_length(size_t rs_lengths);
-
- // Calculate and return the minimum desired young list target
- // length. This is the minimum desired young list length according
- // to the user's inputs.
- uint calculate_young_list_desired_min_length(uint base_min_length) const;
-
- // Calculate and return the maximum desired young list target
- // length. This is the maximum desired young list length according
- // to the user's inputs.
- uint calculate_young_list_desired_max_length() const;
-
- // Calculate and return the maximum young list target length that
- // can fit into the pause time goal. The parameters are: rs_lengths
- // represent the prediction of how large the young RSet lengths will
- // be, base_min_length is the already existing number of regions in
- // the young list, min_length and max_length are the desired min and
- // max young list length according to the user's inputs.
- uint calculate_young_list_target_length(size_t rs_lengths,
- uint base_min_length,
- uint desired_min_length,
- uint desired_max_length) const;
-
- // Result of the bounded_young_list_target_length() method, containing both the
- // bounded as well as the unbounded young list target lengths in this order.
- typedef Pair<uint, uint, StackObj> YoungTargetLengths;
- YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const;
-
- void update_rs_lengths_prediction();
- void update_rs_lengths_prediction(size_t prediction);
-
- // Check whether a given young length (young_length) fits into the
- // given target pause time and whether the prediction for the amount
- // of objects to be copied for the given length will fit into the
- // given free space (expressed by base_free_regions). It is used by
- // calculate_young_list_target_length().
- bool predict_will_fit(uint young_length, double base_time_ms,
- uint base_free_regions, double target_pause_time_ms) const;
-
-public:
- size_t pending_cards() const { return _pending_cards; }
-
- uint calc_min_old_cset_length() const;
- uint calc_max_old_cset_length() const;
-
- // Returns the given amount of reclaimable bytes (that represents
- // the amount of reclaimable space still to be collected) as a
- // percentage of the current heap capacity.
- double reclaimable_bytes_percent(size_t reclaimable_bytes) const;
-
- jlong collection_pause_end_millis() { return _collection_pause_end_millis; }
-
-private:
- // Sets up marking if proper conditions are met.
- void maybe_start_marking();
-
- // The kind of STW pause.
- enum PauseKind {
- FullGC,
- YoungOnlyGC,
- MixedGC,
- LastYoungGC,
- InitialMarkGC,
- Cleanup,
- Remark
- };
-
- // Calculate PauseKind from internal state.
- PauseKind young_gc_pause_kind() const;
- // Record the given STW pause with the given start and end times (in s).
- void record_pause(PauseKind kind, double start, double end);
- // Indicate that we aborted marking before doing any mixed GCs.
- void abort_time_to_mixed_tracking();
-public:
-
- G1DefaultPolicy(STWGCTimer* gc_timer);
-
- virtual ~G1DefaultPolicy();
-
- G1CollectorState* collector_state() const;
-
- G1GCPhaseTimes* phase_times() const { return _phase_times; }
-
- void revise_young_list_target_length_if_necessary(size_t rs_lengths);
-
- void record_new_heap_size(uint new_number_of_regions);
-
- void init(G1CollectedHeap* g1h, G1CollectionSet* collection_set);
-
- virtual void note_gc_start();
-
- bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
-
- bool about_to_start_mixed_phase() const;
-
- void record_collection_pause_start(double start_time_sec);
- void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc);
-
- void record_full_collection_start();
- void record_full_collection_end();
-
- void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
-
- void record_concurrent_mark_remark_start();
- void record_concurrent_mark_remark_end();
-
- void record_concurrent_mark_cleanup_start();
- void record_concurrent_mark_cleanup_end();
- void record_concurrent_mark_cleanup_completed();
-
- virtual void print_phases();
-
- void record_bytes_copied_during_gc(size_t bytes) {
- _bytes_copied_during_gc += bytes;
- }
-
- size_t bytes_copied_during_gc() const {
- return _bytes_copied_during_gc;
- }
-
- bool next_gc_should_be_mixed(const char* true_action_str,
- const char* false_action_str) const;
-
- virtual void finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor);
-private:
- // Set the state to start a concurrent marking cycle and clear
- // _initiate_conc_mark_if_possible because it has now been
- // acted on.
- void initiate_conc_mark();
-
-public:
- bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
-
- void decide_on_conc_mark_initiation();
-
- void finished_recalculating_age_indexes(bool is_survivors) {
- if (is_survivors) {
- _survivor_surv_rate_group->finished_recalculating_age_indexes();
- } else {
- _short_lived_surv_rate_group->finished_recalculating_age_indexes();
- }
- }
-
- size_t young_list_target_length() const { return _young_list_target_length; }
-
- bool should_allocate_mutator_region() const;
-
- bool can_expand_young_list() const;
-
- uint young_list_max_length() const {
- return _young_list_max_length;
- }
-
- bool adaptive_young_list_length() const;
-
- virtual bool should_process_references() const {
- return true;
- }
-
- void transfer_survivors_to_cset(const G1SurvivorRegions* survivors);
-
-private:
- //
- // Survivor regions policy.
- //
-
- // Current tenuring threshold, set to 0 if the collector reaches the
- // maximum amount of survivors regions.
- uint _tenuring_threshold;
-
- // The limit on the number of regions allocated for survivors.
- uint _max_survivor_regions;
-
- AgeTable _survivors_age_table;
-
-protected:
- size_t desired_survivor_size() const;
-public:
- uint tenuring_threshold() const { return _tenuring_threshold; }
-
- uint max_survivor_regions() {
- return _max_survivor_regions;
- }
-
- void note_start_adding_survivor_regions() {
- _survivor_surv_rate_group->start_adding_regions();
- }
-
- void note_stop_adding_survivor_regions() {
- _survivor_surv_rate_group->stop_adding_regions();
- }
-
- void record_age_table(AgeTable* age_table) {
- _survivors_age_table.merge(age_table);
- }
-
- void print_age_table();
-
- void update_max_gc_locker_expansion();
-
- void update_survivors_policy();
-};
-
-#endif // SHARE_VM_GC_G1_G1DEFAULTPOLICY_HPP
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1Policy.cpp Mon Mar 12 09:46:12 2018 +0100
@@ -0,0 +1,1164 @@
+/*
+ * Copyright (c) 2001, 2018, 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/g1/concurrentMarkThread.inline.hpp"
+#include "gc/g1/g1Analytics.hpp"
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1CollectionSet.hpp"
+#include "gc/g1/g1ConcurrentMark.hpp"
+#include "gc/g1/g1ConcurrentRefine.hpp"
+#include "gc/g1/g1HotCardCache.hpp"
+#include "gc/g1/g1IHOPControl.hpp"
+#include "gc/g1/g1GCPhaseTimes.hpp"
+#include "gc/g1/g1Policy.hpp"
+#include "gc/g1/g1SurvivorRegions.hpp"
+#include "gc/g1/g1YoungGenSizer.hpp"
+#include "gc/g1/heapRegion.inline.hpp"
+#include "gc/g1/heapRegionRemSet.hpp"
+#include "gc/shared/gcPolicyCounters.hpp"
+#include "logging/logStream.hpp"
+#include "runtime/arguments.hpp"
+#include "runtime/java.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/growableArray.hpp"
+#include "utilities/pair.hpp"
+
+G1Policy::G1Policy(STWGCTimer* gc_timer) :
+ _predictor(G1ConfidencePercent / 100.0),
+ _analytics(new G1Analytics(&_predictor)),
+ _mmu_tracker(new G1MMUTrackerQueue(GCPauseIntervalMillis / 1000.0, MaxGCPauseMillis / 1000.0)),
+ _ihop_control(create_ihop_control(&_predictor)),
+ _policy_counters(new GCPolicyCounters("GarbageFirst", 1, 2)),
+ _young_list_fixed_length(0),
+ _short_lived_surv_rate_group(new SurvRateGroup()),
+ _survivor_surv_rate_group(new SurvRateGroup()),
+ _reserve_factor((double) G1ReservePercent / 100.0),
+ _reserve_regions(0),
+ _rs_lengths_prediction(0),
+ _bytes_allocated_in_old_since_last_gc(0),
+ _initial_mark_to_mixed(),
+ _collection_set(NULL),
+ _g1(NULL),
+ _phase_times(new G1GCPhaseTimes(gc_timer, ParallelGCThreads)),
+ _tenuring_threshold(MaxTenuringThreshold),
+ _max_survivor_regions(0),
+ _survivors_age_table(true),
+ _collection_pause_end_millis(os::javaTimeNanos() / NANOSECS_PER_MILLISEC) { }
+
+G1Policy::~G1Policy() {
+ delete _ihop_control;
+}
+
+G1CollectorState* G1Policy::collector_state() const { return _g1->collector_state(); }
+
+void G1Policy::init(G1CollectedHeap* g1h, G1CollectionSet* collection_set) {
+ _g1 = g1h;
+ _collection_set = collection_set;
+
+ assert(Heap_lock->owned_by_self(), "Locking discipline.");
+
+ if (!adaptive_young_list_length()) {
+ _young_list_fixed_length = _young_gen_sizer.min_desired_young_length();
+ }
+ _young_gen_sizer.adjust_max_new_size(_g1->max_regions());
+
+ _free_regions_at_end_of_collection = _g1->num_free_regions();
+
+ update_young_list_max_and_target_length();
+ // We may immediately start allocating regions and placing them on the
+ // collection set list. Initialize the per-collection set info
+ _collection_set->start_incremental_building();
+}
+
+void G1Policy::note_gc_start() {
+ phase_times()->note_gc_start();
+}
+
+class G1YoungLengthPredictor VALUE_OBJ_CLASS_SPEC {
+ const bool _during_cm;
+ const double _base_time_ms;
+ const double _base_free_regions;
+ const double _target_pause_time_ms;
+ const G1Policy* const _policy;
+
+ public:
+ G1YoungLengthPredictor(bool during_cm,
+ double base_time_ms,
+ double base_free_regions,
+ double target_pause_time_ms,
+ const G1Policy* policy) :
+ _during_cm(during_cm),
+ _base_time_ms(base_time_ms),
+ _base_free_regions(base_free_regions),
+ _target_pause_time_ms(target_pause_time_ms),
+ _policy(policy) {}
+
+ bool will_fit(uint young_length) const {
+ if (young_length >= _base_free_regions) {
+ // end condition 1: not enough space for the young regions
+ return false;
+ }
+
+ const double accum_surv_rate = _policy->accum_yg_surv_rate_pred((int) young_length - 1);
+ const size_t bytes_to_copy =
+ (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
+ const double copy_time_ms =
+ _policy->analytics()->predict_object_copy_time_ms(bytes_to_copy, _during_cm);
+ const double young_other_time_ms = _policy->analytics()->predict_young_other_time_ms(young_length);
+ const 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: prediction is over the target pause time
+ return false;
+ }
+
+ const size_t free_bytes = (_base_free_regions - young_length) * HeapRegion::GrainBytes;
+
+ // When copying, we will likely need more bytes free than is live in the region.
+ // Add some safety margin to factor in the confidence of our guess, and the
+ // natural expected waste.
+ // (100.0 / G1ConfidencePercent) is a scale factor that expresses the uncertainty
+ // of the calculation: the lower the confidence, the more headroom.
+ // (100 + TargetPLABWastePct) represents the increase in expected bytes during
+ // copying due to anticipated waste in the PLABs.
+ const double safety_factor = (100.0 / G1ConfidencePercent) * (100 + TargetPLABWastePct) / 100.0;
+ const size_t expected_bytes_to_copy = (size_t)(safety_factor * bytes_to_copy);
+
+ if (expected_bytes_to_copy > free_bytes) {
+ // end condition 3: out-of-space
+ return false;
+ }
+
+ // success!
+ return true;
+ }
+};
+
+void G1Policy::record_new_heap_size(uint new_number_of_regions) {
+ // re-calculate the necessary reserve
+ double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
+ // We use ceiling so that if reserve_regions_d is > 0.0 (but
+ // smaller than 1.0) we'll get 1.
+ _reserve_regions = (uint) ceil(reserve_regions_d);
+
+ _young_gen_sizer.heap_size_changed(new_number_of_regions);
+
+ _ihop_control->update_target_occupancy(new_number_of_regions * HeapRegion::GrainBytes);
+}
+
+uint G1Policy::calculate_young_list_desired_min_length(uint base_min_length) const {
+ uint desired_min_length = 0;
+ if (adaptive_young_list_length()) {
+ if (_analytics->num_alloc_rate_ms() > 3) {
+ double now_sec = os::elapsedTime();
+ double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
+ double alloc_rate_ms = _analytics->predict_alloc_rate_ms();
+ desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
+ } else {
+ // otherwise we don't have enough info to make the prediction
+ }
+ }
+ desired_min_length += base_min_length;
+ // make sure we don't go below any user-defined minimum bound
+ return MAX2(_young_gen_sizer.min_desired_young_length(), desired_min_length);
+}
+
+uint G1Policy::calculate_young_list_desired_max_length() const {
+ // Here, we might want to also take into account any additional
+ // constraints (i.e., user-defined minimum bound). Currently, we
+ // effectively don't set this bound.
+ return _young_gen_sizer.max_desired_young_length();
+}
+
+uint G1Policy::update_young_list_max_and_target_length() {
+ return update_young_list_max_and_target_length(_analytics->predict_rs_lengths());
+}
+
+uint G1Policy::update_young_list_max_and_target_length(size_t rs_lengths) {
+ uint unbounded_target_length = update_young_list_target_length(rs_lengths);
+ update_max_gc_locker_expansion();
+ return unbounded_target_length;
+}
+
+uint G1Policy::update_young_list_target_length(size_t rs_lengths) {
+ YoungTargetLengths young_lengths = young_list_target_lengths(rs_lengths);
+ _young_list_target_length = young_lengths.first;
+ return young_lengths.second;
+}
+
+G1Policy::YoungTargetLengths G1Policy::young_list_target_lengths(size_t rs_lengths) const {
+ YoungTargetLengths result;
+
+ // Calculate the absolute and desired min bounds first.
+
+ // This is how many young regions we already have (currently: the survivors).
+ const uint base_min_length = _g1->survivor_regions_count();
+ uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
+ // This is the absolute minimum young length. Ensure that we
+ // will at least have one eden region available for allocation.
+ uint absolute_min_length = base_min_length + MAX2(_g1->eden_regions_count(), (uint)1);
+ // If we shrank the young list target it should not shrink below the current size.
+ desired_min_length = MAX2(desired_min_length, absolute_min_length);
+ // Calculate the absolute and desired max bounds.
+
+ uint desired_max_length = calculate_young_list_desired_max_length();
+
+ uint young_list_target_length = 0;
+ if (adaptive_young_list_length()) {
+ if (collector_state()->gcs_are_young()) {
+ young_list_target_length =
+ calculate_young_list_target_length(rs_lengths,
+ base_min_length,
+ desired_min_length,
+ desired_max_length);
+ } else {
+ // Don't calculate anything and let the code below bound it to
+ // the desired_min_length, i.e., do the next GC as soon as
+ // possible to maximize how many old regions we can add to it.
+ }
+ } else {
+ // The user asked for a fixed young gen so we'll fix the young gen
+ // whether the next GC is young or mixed.
+ young_list_target_length = _young_list_fixed_length;
+ }
+
+ result.second = young_list_target_length;
+
+ // We will try our best not to "eat" into the reserve.
+ uint absolute_max_length = 0;
+ if (_free_regions_at_end_of_collection > _reserve_regions) {
+ absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
+ }
+ if (desired_max_length > absolute_max_length) {
+ desired_max_length = absolute_max_length;
+ }
+
+ // Make sure we don't go over the desired max length, nor under the
+ // desired min length. In case they clash, desired_min_length wins
+ // which is why that test is second.
+ if (young_list_target_length > desired_max_length) {
+ young_list_target_length = desired_max_length;
+ }
+ if (young_list_target_length < desired_min_length) {
+ young_list_target_length = desired_min_length;
+ }
+
+ assert(young_list_target_length > base_min_length,
+ "we should be able to allocate at least one eden region");
+ assert(young_list_target_length >= absolute_min_length, "post-condition");
+
+ result.first = young_list_target_length;
+ return result;
+}
+
+uint
+G1Policy::calculate_young_list_target_length(size_t rs_lengths,
+ uint base_min_length,
+ uint desired_min_length,
+ uint desired_max_length) const {
+ assert(adaptive_young_list_length(), "pre-condition");
+ assert(collector_state()->gcs_are_young(), "only call this for young GCs");
+
+ // In case some edge-condition makes the desired max length too small...
+ if (desired_max_length <= desired_min_length) {
+ return desired_min_length;
+ }
+
+ // We'll adjust min_young_length and max_young_length not to include
+ // the already allocated young regions (i.e., so they reflect the
+ // min and max eden regions we'll allocate). The base_min_length
+ // will be reflected in the predictions by the
+ // survivor_regions_evac_time prediction.
+ assert(desired_min_length > base_min_length, "invariant");
+ uint min_young_length = desired_min_length - base_min_length;
+ assert(desired_max_length > base_min_length, "invariant");
+ uint max_young_length = desired_max_length - base_min_length;
+
+ const double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
+ const double survivor_regions_evac_time = predict_survivor_regions_evac_time();
+ const size_t pending_cards = _analytics->predict_pending_cards();
+ const size_t adj_rs_lengths = rs_lengths + _analytics->predict_rs_length_diff();
+ const size_t scanned_cards = _analytics->predict_card_num(adj_rs_lengths, /* gcs_are_young */ true);
+ const double base_time_ms =
+ predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
+ survivor_regions_evac_time;
+ const uint available_free_regions = _free_regions_at_end_of_collection;
+ const uint base_free_regions =
+ available_free_regions > _reserve_regions ? available_free_regions - _reserve_regions : 0;
+
+ // Here, we will make sure that the shortest young length that
+ // makes sense fits within the target pause time.
+
+ G1YoungLengthPredictor p(collector_state()->during_concurrent_mark(),
+ base_time_ms,
+ base_free_regions,
+ target_pause_time_ms,
+ this);
+ if (p.will_fit(min_young_length)) {
+ // The shortest young length will fit into 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.
+ if (p.will_fit(max_young_length)) {
+ // The maximum young length will fit into the target pause time.
+ // We are done so set min young length to the maximum length (as
+ // the result is assumed to be returned in min_young_length).
+ min_young_length = max_young_length;
+ } else {
+ // The maximum possible number of young regions will not fit within
+ // the target pause time so we'll search for the optimal
+ // length. The loop invariants are:
+ //
+ // min_young_length < max_young_length
+ // min_young_length is known to fit into the target pause time
+ // max_young_length is known not to fit into the target pause time
+ //
+ // Going into the loop we know the above hold as we've just
+ // checked them. Every time around the loop we check whether
+ // the middle value between min_young_length and
+ // max_young_length fits into the target pause time. If it
+ // does, it becomes the new min. If it doesn't, it becomes
+ // the new max. This way we maintain the loop invariants.
+
+ assert(min_young_length < max_young_length, "invariant");
+ uint diff = (max_young_length - min_young_length) / 2;
+ while (diff > 0) {
+ uint young_length = min_young_length + diff;
+ if (p.will_fit(young_length)) {
+ min_young_length = young_length;
+ } else {
+ max_young_length = young_length;
+ }
+ assert(min_young_length < max_young_length, "invariant");
+ diff = (max_young_length - min_young_length) / 2;
+ }
+ // The results is min_young_length which, according to the
+ // loop invariants, should fit within the target pause time.
+
+ // These are the post-conditions of the binary search above:
+ assert(min_young_length < max_young_length,
+ "otherwise we should have discovered that max_young_length "
+ "fits into the pause target and not done the binary search");
+ assert(p.will_fit(min_young_length),
+ "min_young_length, the result of the binary search, should "
+ "fit into the pause target");
+ assert(!p.will_fit(min_young_length + 1),
+ "min_young_length, the result of the binary search, should be "
+ "optimal, so no larger length should fit into the pause target");
+ }
+ } else {
+ // Even the minimum length doesn't fit into the pause time
+ // target, return it as the result nevertheless.
+ }
+ return base_min_length + min_young_length;
+}
+
+double G1Policy::predict_survivor_regions_evac_time() const {
+ double survivor_regions_evac_time = 0.0;
+ const GrowableArray<HeapRegion*>* survivor_regions = _g1->survivor()->regions();
+
+ for (GrowableArrayIterator<HeapRegion*> it = survivor_regions->begin();
+ it != survivor_regions->end();
+ ++it) {
+ survivor_regions_evac_time += predict_region_elapsed_time_ms(*it, collector_state()->gcs_are_young());
+ }
+ return survivor_regions_evac_time;
+}
+
+void G1Policy::revise_young_list_target_length_if_necessary(size_t rs_lengths) {
+ guarantee( adaptive_young_list_length(), "should not call this otherwise" );
+
+ if (rs_lengths > _rs_lengths_prediction) {
+ // add 10% to avoid having to recalculate often
+ size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
+ update_rs_lengths_prediction(rs_lengths_prediction);
+
+ update_young_list_max_and_target_length(rs_lengths_prediction);
+ }
+}
+
+void G1Policy::update_rs_lengths_prediction() {
+ update_rs_lengths_prediction(_analytics->predict_rs_lengths());
+}
+
+void G1Policy::update_rs_lengths_prediction(size_t prediction) {
+ if (collector_state()->gcs_are_young() && adaptive_young_list_length()) {
+ _rs_lengths_prediction = prediction;
+ }
+}
+
+void G1Policy::record_full_collection_start() {
+ _full_collection_start_sec = os::elapsedTime();
+ // Release the future to-space so that it is available for compaction into.
+ collector_state()->set_full_collection(true);
+}
+
+void G1Policy::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 - _full_collection_start_sec;
+ double full_gc_time_ms = full_gc_time_sec * 1000.0;
+
+ _analytics->update_recent_gc_times(end_sec, full_gc_time_ms);
+
+ collector_state()->set_full_collection(false);
+
+ // "Nuke" the heuristics that control the young/mixed GC
+ // transitions and make sure we start with young GCs after the Full GC.
+ collector_state()->set_gcs_are_young(true);
+ collector_state()->set_last_young_gc(false);
+ collector_state()->set_initiate_conc_mark_if_possible(need_to_start_conc_mark("end of Full GC", 0));
+ collector_state()->set_during_initial_mark_pause(false);
+ collector_state()->set_in_marking_window(false);
+ collector_state()->set_in_marking_window_im(false);
+
+ _short_lived_surv_rate_group->start_adding_regions();
+ // also call this on any additional surv rate groups
+
+ _free_regions_at_end_of_collection = _g1->num_free_regions();
+ // Reset survivors SurvRateGroup.
+ _survivor_surv_rate_group->reset();
+ update_young_list_max_and_target_length();
+ update_rs_lengths_prediction();
+ cset_chooser()->clear();
+
+ _bytes_allocated_in_old_since_last_gc = 0;
+
+ record_pause(FullGC, _full_collection_start_sec, end_sec);
+}
+
+void G1Policy::record_collection_pause_start(double start_time_sec) {
+ // We only need to do this here as the policy will only be applied
+ // to the GC we're about to start. so, no point is calculating this
+ // every time we calculate / recalculate the target young length.
+ update_survivors_policy();
+
+ assert(_g1->used() == _g1->recalculate_used(),
+ "sanity, used: " SIZE_FORMAT " recalculate_used: " SIZE_FORMAT,
+ _g1->used(), _g1->recalculate_used());
+
+ phase_times()->record_cur_collection_start_sec(start_time_sec);
+ _pending_cards = _g1->pending_card_num();
+
+ _collection_set->reset_bytes_used_before();
+ _bytes_copied_during_gc = 0;
+
+ collector_state()->set_last_gc_was_young(false);
+
+ // do that for any other surv rate groups
+ _short_lived_surv_rate_group->stop_adding_regions();
+ _survivors_age_table.clear();
+
+ assert(_g1->collection_set()->verify_young_ages(), "region age verification failed");
+}
+
+void G1Policy::record_concurrent_mark_init_end(double mark_init_elapsed_time_ms) {
+ collector_state()->set_during_marking(true);
+ assert(!collector_state()->initiate_conc_mark_if_possible(), "we should have cleared it by now");
+ collector_state()->set_during_initial_mark_pause(false);
+}
+
+void G1Policy::record_concurrent_mark_remark_start() {
+ _mark_remark_start_sec = os::elapsedTime();
+ collector_state()->set_during_marking(false);
+}
+
+void G1Policy::record_concurrent_mark_remark_end() {
+ double end_time_sec = os::elapsedTime();
+ double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
+ _analytics->report_concurrent_mark_remark_times_ms(elapsed_time_ms);
+ _analytics->append_prev_collection_pause_end_ms(elapsed_time_ms);
+
+ record_pause(Remark, _mark_remark_start_sec, end_time_sec);
+}
+
+void G1Policy::record_concurrent_mark_cleanup_start() {
+ _mark_cleanup_start_sec = os::elapsedTime();
+}
+
+void G1Policy::record_concurrent_mark_cleanup_completed() {
+ bool should_continue_with_reclaim = next_gc_should_be_mixed("request last young-only gc",
+ "skip last young-only gc");
+ collector_state()->set_last_young_gc(should_continue_with_reclaim);
+ // We skip the marking phase.
+ if (!should_continue_with_reclaim) {
+ abort_time_to_mixed_tracking();
+ }
+ collector_state()->set_in_marking_window(false);
+}
+
+double G1Policy::average_time_ms(G1GCPhaseTimes::GCParPhases phase) const {
+ return phase_times()->average_time_ms(phase);
+}
+
+double G1Policy::young_other_time_ms() const {
+ return phase_times()->young_cset_choice_time_ms() +
+ phase_times()->average_time_ms(G1GCPhaseTimes::YoungFreeCSet);
+}
+
+double G1Policy::non_young_other_time_ms() const {
+ return phase_times()->non_young_cset_choice_time_ms() +
+ phase_times()->average_time_ms(G1GCPhaseTimes::NonYoungFreeCSet);
+}
+
+double G1Policy::other_time_ms(double pause_time_ms) const {
+ return pause_time_ms - phase_times()->cur_collection_par_time_ms();
+}
+
+double G1Policy::constant_other_time_ms(double pause_time_ms) const {
+ return other_time_ms(pause_time_ms) - phase_times()->total_free_cset_time_ms();
+}
+
+CollectionSetChooser* G1Policy::cset_chooser() const {
+ return _collection_set->cset_chooser();
+}
+
+bool G1Policy::about_to_start_mixed_phase() const {
+ return _g1->concurrent_mark()->cm_thread()->during_cycle() || collector_state()->last_young_gc();
+}
+
+bool G1Policy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
+ if (about_to_start_mixed_phase()) {
+ return false;
+ }
+
+ size_t marking_initiating_used_threshold = _ihop_control->get_conc_mark_start_threshold();
+
+ size_t cur_used_bytes = _g1->non_young_capacity_bytes();
+ size_t alloc_byte_size = alloc_word_size * HeapWordSize;
+ size_t marking_request_bytes = cur_used_bytes + alloc_byte_size;
+
+ bool result = false;
+ if (marking_request_bytes > marking_initiating_used_threshold) {
+ result = collector_state()->gcs_are_young() && !collector_state()->last_young_gc();
+ log_debug(gc, ergo, ihop)("%s occupancy: " SIZE_FORMAT "B allocation request: " SIZE_FORMAT "B threshold: " SIZE_FORMAT "B (%1.2f) source: %s",
+ result ? "Request concurrent cycle initiation (occupancy higher than threshold)" : "Do not request concurrent cycle initiation (still doing mixed collections)",
+ cur_used_bytes, alloc_byte_size, marking_initiating_used_threshold, (double) marking_initiating_used_threshold / _g1->capacity() * 100, source);
+ }
+
+ return result;
+}
+
+// Anything below that is considered to be zero
+#define MIN_TIMER_GRANULARITY 0.0000001
+
+void G1Policy::record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc) {
+ double end_time_sec = os::elapsedTime();
+
+ 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();
+
+ record_pause(young_gc_pause_kind(), end_time_sec - pause_time_ms / 1000.0, end_time_sec);
+
+ _collection_pause_end_millis = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
+
+ last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
+ if (last_pause_included_initial_mark) {
+ record_concurrent_mark_init_end(0.0);
+ } else {
+ maybe_start_marking();
+ }
+
+ double app_time_ms = (phase_times()->cur_collection_start_sec() * 1000.0 - _analytics->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;
+ }
+
+ if (update_stats) {
+ // We maintain the invariant that all objects allocated by mutator
+ // threads will be allocated out of eden regions. So, we can use
+ // the eden region number allocated since the previous GC to
+ // calculate the application's allocate rate. The only exception
+ // to that is humongous objects that are allocated separately. But
+ // given that humongous object allocations do not really affect
+ // either the pause's duration nor when the next pause will take
+ // place we can safely ignore them here.
+ uint regions_allocated = _collection_set->eden_region_length();
+ double alloc_rate_ms = (double) regions_allocated / app_time_ms;
+ _analytics->report_alloc_rate_ms(alloc_rate_ms);
+
+ double interval_ms =
+ (end_time_sec - _analytics->last_known_gc_end_time_sec()) * 1000.0;
+ _analytics->update_recent_gc_times(end_time_sec, pause_time_ms);
+ _analytics->compute_pause_time_ratio(interval_ms, pause_time_ms);
+ }
+
+ bool new_in_marking_window = collector_state()->in_marking_window();
+ bool new_in_marking_window_im = false;
+ if (last_pause_included_initial_mark) {
+ new_in_marking_window = true;
+ new_in_marking_window_im = true;
+ }
+
+ if (collector_state()->last_young_gc()) {
+ // This is supposed to to be the "last young GC" before we start
+ // doing mixed GCs. Here we decide whether to start mixed GCs or not.
+ assert(!last_pause_included_initial_mark, "The last young GC is not allowed to be an initial mark GC");
+
+ if (next_gc_should_be_mixed("start mixed GCs",
+ "do not start mixed GCs")) {
+ collector_state()->set_gcs_are_young(false);
+ } else {
+ // We aborted the mixed GC phase early.
+ abort_time_to_mixed_tracking();
+ }
+
+ collector_state()->set_last_young_gc(false);
+ }
+
+ if (!collector_state()->last_gc_was_young()) {
+ // This is a mixed GC. Here we decide whether to continue doing
+ // mixed GCs or not.
+ if (!next_gc_should_be_mixed("continue mixed GCs",
+ "do not continue mixed GCs")) {
+ collector_state()->set_gcs_are_young(true);
+
+ maybe_start_marking();
+ }
+ }
+
+ _short_lived_surv_rate_group->start_adding_regions();
+ // Do that for any other surv rate groups
+
+ double scan_hcc_time_ms = G1HotCardCache::default_use_cache() ? average_time_ms(G1GCPhaseTimes::ScanHCC) : 0.0;
+
+ if (update_stats) {
+ double cost_per_card_ms = 0.0;
+ if (_pending_cards > 0) {
+ cost_per_card_ms = (average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms) / (double) _pending_cards;
+ _analytics->report_cost_per_card_ms(cost_per_card_ms);
+ }
+ _analytics->report_cost_scan_hcc(scan_hcc_time_ms);
+
+ double cost_per_entry_ms = 0.0;
+ if (cards_scanned > 10) {
+ cost_per_entry_ms = average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
+ _analytics->report_cost_per_entry_ms(cost_per_entry_ms, collector_state()->last_gc_was_young());
+ }
+
+ if (_max_rs_lengths > 0) {
+ double cards_per_entry_ratio =
+ (double) cards_scanned / (double) _max_rs_lengths;
+ _analytics->report_cards_per_entry_ratio(cards_per_entry_ratio, collector_state()->last_gc_was_young());
+ }
+
+ // This is defensive. For a while _max_rs_lengths could get
+ // smaller than _recorded_rs_lengths which was causing
+ // rs_length_diff to get very large and mess up the RSet length
+ // predictions. The reason was unsafe concurrent updates to the
+ // _inc_cset_recorded_rs_lengths field which the code below guards
+ // against (see CR 7118202). This bug has now been fixed (see CR
+ // 7119027). However, I'm still worried that
+ // _inc_cset_recorded_rs_lengths might still end up somewhat
+ // inaccurate. The concurrent refinement thread calculates an
+ // RSet's length concurrently with other CR threads updating it
+ // which might cause it to calculate the length incorrectly (if,
+ // say, it's in mid-coarsening). So I'll leave in the defensive
+ // conditional below just in case.
+ size_t rs_length_diff = 0;
+ size_t recorded_rs_lengths = _collection_set->recorded_rs_lengths();
+ if (_max_rs_lengths > recorded_rs_lengths) {
+ rs_length_diff = _max_rs_lengths - recorded_rs_lengths;
+ }
+ _analytics->report_rs_length_diff((double) rs_length_diff);
+
+ size_t freed_bytes = heap_used_bytes_before_gc - cur_used_bytes;
+ size_t copied_bytes = _collection_set->bytes_used_before() - freed_bytes;
+ double cost_per_byte_ms = 0.0;
+
+ if (copied_bytes > 0) {
+ cost_per_byte_ms = average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
+ _analytics->report_cost_per_byte_ms(cost_per_byte_ms, collector_state()->in_marking_window());
+ }
+
+ if (_collection_set->young_region_length() > 0) {
+ _analytics->report_young_other_cost_per_region_ms(young_other_time_ms() /
+ _collection_set->young_region_length());
+ }
+
+ if (_collection_set->old_region_length() > 0) {
+ _analytics->report_non_young_other_cost_per_region_ms(non_young_other_time_ms() /
+ _collection_set->old_region_length());
+ }
+
+ _analytics->report_constant_other_time_ms(constant_other_time_ms(pause_time_ms));
+
+ _analytics->report_pending_cards((double) _pending_cards);
+ _analytics->report_rs_lengths((double) _max_rs_lengths);
+ }
+
+ collector_state()->set_in_marking_window(new_in_marking_window);
+ collector_state()->set_in_marking_window_im(new_in_marking_window_im);
+ _free_regions_at_end_of_collection = _g1->num_free_regions();
+ // IHOP control wants to know the expected young gen length if it were not
+ // restrained by the heap reserve. Using the actual length would make the
+ // prediction too small and the limit the young gen every time we get to the
+ // predicted target occupancy.
+ size_t last_unrestrained_young_length = update_young_list_max_and_target_length();
+ update_rs_lengths_prediction();
+
+ update_ihop_prediction(app_time_ms / 1000.0,
+ _bytes_allocated_in_old_since_last_gc,
+ last_unrestrained_young_length * HeapRegion::GrainBytes);
+ _bytes_allocated_in_old_since_last_gc = 0;
+
+ _ihop_control->send_trace_event(_g1->gc_tracer_stw());
+
+ // 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;
+
+ if (update_rs_time_goal_ms < scan_hcc_time_ms) {
+ log_debug(gc, ergo, refine)("Adjust concurrent refinement thresholds (scanning the HCC expected to take longer than Update RS time goal)."
+ "Update RS time goal: %1.2fms Scan HCC time: %1.2fms",
+ update_rs_time_goal_ms, scan_hcc_time_ms);
+
+ update_rs_time_goal_ms = 0;
+ } else {
+ update_rs_time_goal_ms -= scan_hcc_time_ms;
+ }
+ _g1->concurrent_refine()->adjust(average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms,
+ phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS),
+ update_rs_time_goal_ms);
+
+ cset_chooser()->verify();
+}
+
+G1IHOPControl* G1Policy::create_ihop_control(const G1Predictions* predictor){
+ if (G1UseAdaptiveIHOP) {
+ return new G1AdaptiveIHOPControl(InitiatingHeapOccupancyPercent,
+ predictor,
+ G1ReservePercent,
+ G1HeapWastePercent);
+ } else {
+ return new G1StaticIHOPControl(InitiatingHeapOccupancyPercent);
+ }
+}
+
+void G1Policy::update_ihop_prediction(double mutator_time_s,
+ size_t mutator_alloc_bytes,
+ size_t young_gen_size) {
+ // Always try to update IHOP prediction. Even evacuation failures give information
+ // about e.g. whether to start IHOP earlier next time.
+
+ // Avoid using really small application times that might create samples with
+ // very high or very low values. They may be caused by e.g. back-to-back gcs.
+ double const min_valid_time = 1e-6;
+
+ bool report = false;
+
+ double marking_to_mixed_time = -1.0;
+ if (!collector_state()->last_gc_was_young() && _initial_mark_to_mixed.has_result()) {
+ marking_to_mixed_time = _initial_mark_to_mixed.last_marking_time();
+ assert(marking_to_mixed_time > 0.0,
+ "Initial mark to mixed time must be larger than zero but is %.3f",
+ marking_to_mixed_time);
+ if (marking_to_mixed_time > min_valid_time) {
+ _ihop_control->update_marking_length(marking_to_mixed_time);
+ report = true;
+ }
+ }
+
+ // As an approximation for the young gc promotion rates during marking we use
+ // all of them. In many applications there are only a few if any young gcs during
+ // marking, which makes any prediction useless. This increases the accuracy of the
+ // prediction.
+ if (collector_state()->last_gc_was_young() && mutator_time_s > min_valid_time) {
+ _ihop_control->update_allocation_info(mutator_time_s, mutator_alloc_bytes, young_gen_size);
+ report = true;
+ }
+
+ if (report) {
+ report_ihop_statistics();
+ }
+}
+
+void G1Policy::report_ihop_statistics() {
+ _ihop_control->print();
+}
+
+void G1Policy::print_phases() {
+ phase_times()->print();
+}
+
+double G1Policy::predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const {
+ TruncatedSeq* seq = surv_rate_group->get_seq(age);
+ guarantee(seq->num() > 0, "There should be some young gen survivor samples available. Tried to access with age %d", age);
+ double pred = _predictor.get_new_prediction(seq);
+ if (pred > 1.0) {
+ pred = 1.0;
+ }
+ return pred;
+}
+
+double G1Policy::accum_yg_surv_rate_pred(int age) const {
+ return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
+}
+
+double G1Policy::predict_base_elapsed_time_ms(size_t pending_cards,
+ size_t scanned_cards) const {
+ return
+ _analytics->predict_rs_update_time_ms(pending_cards) +
+ _analytics->predict_rs_scan_time_ms(scanned_cards, collector_state()->gcs_are_young()) +
+ _analytics->predict_constant_other_time_ms();
+}
+
+double G1Policy::predict_base_elapsed_time_ms(size_t pending_cards) const {
+ size_t rs_length = _analytics->predict_rs_lengths() + _analytics->predict_rs_length_diff();
+ size_t card_num = _analytics->predict_card_num(rs_length, collector_state()->gcs_are_young());
+ return predict_base_elapsed_time_ms(pending_cards, card_num);
+}
+
+size_t G1Policy::predict_bytes_to_copy(HeapRegion* hr) const {
+ size_t bytes_to_copy;
+ if (hr->is_marked())
+ bytes_to_copy = hr->max_live_bytes();
+ else {
+ assert(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) (hr->used() * yg_surv_rate);
+ }
+ return bytes_to_copy;
+}
+
+double G1Policy::predict_region_elapsed_time_ms(HeapRegion* hr,
+ bool for_young_gc) const {
+ size_t rs_length = hr->rem_set()->occupied();
+ // Predicting the number of cards is based on which type of GC
+ // we're predicting for.
+ size_t card_num = _analytics->predict_card_num(rs_length, for_young_gc);
+ size_t bytes_to_copy = predict_bytes_to_copy(hr);
+
+ double region_elapsed_time_ms =
+ _analytics->predict_rs_scan_time_ms(card_num, collector_state()->gcs_are_young()) +
+ _analytics->predict_object_copy_time_ms(bytes_to_copy, collector_state()->during_concurrent_mark());
+
+ // The prediction of the "other" time for this region is based
+ // upon the region type and NOT the GC type.
+ if (hr->is_young()) {
+ region_elapsed_time_ms += _analytics->predict_young_other_time_ms(1);
+ } else {
+ region_elapsed_time_ms += _analytics->predict_non_young_other_time_ms(1);
+ }
+ return region_elapsed_time_ms;
+}
+
+bool G1Policy::should_allocate_mutator_region() const {
+ uint young_list_length = _g1->young_regions_count();
+ uint young_list_target_length = _young_list_target_length;
+ return young_list_length < young_list_target_length;
+}
+
+bool G1Policy::can_expand_young_list() const {
+ uint young_list_length = _g1->young_regions_count();
+ uint young_list_max_length = _young_list_max_length;
+ return young_list_length < young_list_max_length;
+}
+
+bool G1Policy::adaptive_young_list_length() const {
+ return _young_gen_sizer.adaptive_young_list_length();
+}
+
+size_t G1Policy::desired_survivor_size() const {
+ size_t const survivor_capacity = HeapRegion::GrainWords * _max_survivor_regions;
+ return (size_t)((((double)survivor_capacity) * TargetSurvivorRatio) / 100);
+}
+
+void G1Policy::print_age_table() {
+ _survivors_age_table.print_age_table(_tenuring_threshold);
+}
+
+void G1Policy::update_max_gc_locker_expansion() {
+ uint 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 = (uint) 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 G1Policy::update_survivors_policy() {
+ double max_survivor_regions_d =
+ (double) _young_list_target_length / (double) SurvivorRatio;
+ // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
+ // smaller than 1.0) we'll get 1.
+ _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
+
+ _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(desired_survivor_size());
+ if (UsePerfData) {
+ _policy_counters->tenuring_threshold()->set_value(_tenuring_threshold);
+ _policy_counters->desired_survivor_size()->set_value(desired_survivor_size() * oopSize);
+ }
+}
+
+bool G1Policy::force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause) {
+ // We actually check whether we are marking here and not if we are in a
+ // reclamation phase. This means that we will schedule a concurrent mark
+ // even while we are still in the process of reclaiming memory.
+ bool during_cycle = _g1->concurrent_mark()->cm_thread()->during_cycle();
+ if (!during_cycle) {
+ log_debug(gc, ergo)("Request concurrent cycle initiation (requested by GC cause). GC cause: %s", GCCause::to_string(gc_cause));
+ collector_state()->set_initiate_conc_mark_if_possible(true);
+ return true;
+ } else {
+ log_debug(gc, ergo)("Do not request concurrent cycle initiation (concurrent cycle already in progress). GC cause: %s", GCCause::to_string(gc_cause));
+ return false;
+ }
+}
+
+void G1Policy::initiate_conc_mark() {
+ collector_state()->set_during_initial_mark_pause(true);
+ collector_state()->set_initiate_conc_mark_if_possible(false);
+}
+
+void G1Policy::decide_on_conc_mark_initiation() {
+ // We are about to decide on whether this pause will be an
+ // initial-mark pause.
+
+ // First, collector_state()->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(!collector_state()->during_initial_mark_pause(), "pre-condition");
+
+ if (collector_state()->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.
+
+ if (!about_to_start_mixed_phase() && collector_state()->gcs_are_young()) {
+ // Initiate a new initial mark if there is no marking or reclamation going on.
+ initiate_conc_mark();
+ log_debug(gc, ergo)("Initiate concurrent cycle (concurrent cycle initiation requested)");
+ } else if (_g1->is_user_requested_concurrent_full_gc(_g1->gc_cause())) {
+ // Initiate a user requested initial mark. An initial mark must be young only
+ // GC, so the collector state must be updated to reflect this.
+ collector_state()->set_gcs_are_young(true);
+ collector_state()->set_last_young_gc(false);
+
+ abort_time_to_mixed_tracking();
+ initiate_conc_mark();
+ log_debug(gc, ergo)("Initiate concurrent cycle (user requested concurrent cycle)");
+ } 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.
+ log_debug(gc, ergo)("Do not initiate concurrent cycle (concurrent cycle already in progress)");
+ }
+ }
+}
+
+void G1Policy::record_concurrent_mark_cleanup_end() {
+ cset_chooser()->rebuild(_g1->workers(), _g1->num_regions());
+
+ double end_sec = os::elapsedTime();
+ double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
+ _analytics->report_concurrent_mark_cleanup_times_ms(elapsed_time_ms);
+ _analytics->append_prev_collection_pause_end_ms(elapsed_time_ms);
+
+ record_pause(Cleanup, _mark_cleanup_start_sec, end_sec);
+}
+
+double G1Policy::reclaimable_bytes_percent(size_t reclaimable_bytes) const {
+ return percent_of(reclaimable_bytes, _g1->capacity());
+}
+
+void G1Policy::maybe_start_marking() {
+ if (need_to_start_conc_mark("end of GC")) {
+ // 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.
+ collector_state()->set_initiate_conc_mark_if_possible(true);
+ }
+}
+
+G1Policy::PauseKind G1Policy::young_gc_pause_kind() const {
+ assert(!collector_state()->full_collection(), "must be");
+ if (collector_state()->during_initial_mark_pause()) {
+ assert(collector_state()->last_gc_was_young(), "must be");
+ assert(!collector_state()->last_young_gc(), "must be");
+ return InitialMarkGC;
+ } else if (collector_state()->last_young_gc()) {
+ assert(!collector_state()->during_initial_mark_pause(), "must be");
+ assert(collector_state()->last_gc_was_young(), "must be");
+ return LastYoungGC;
+ } else if (!collector_state()->last_gc_was_young()) {
+ assert(!collector_state()->during_initial_mark_pause(), "must be");
+ assert(!collector_state()->last_young_gc(), "must be");
+ return MixedGC;
+ } else {
+ assert(collector_state()->last_gc_was_young(), "must be");
+ assert(!collector_state()->during_initial_mark_pause(), "must be");
+ assert(!collector_state()->last_young_gc(), "must be");
+ return YoungOnlyGC;
+ }
+}
+
+void G1Policy::record_pause(PauseKind kind, double start, double end) {
+ // Manage the MMU tracker. For some reason it ignores Full GCs.
+ if (kind != FullGC) {
+ _mmu_tracker->add_pause(start, end);
+ }
+ // Manage the mutator time tracking from initial mark to first mixed gc.
+ switch (kind) {
+ case FullGC:
+ abort_time_to_mixed_tracking();
+ break;
+ case Cleanup:
+ case Remark:
+ case YoungOnlyGC:
+ case LastYoungGC:
+ _initial_mark_to_mixed.add_pause(end - start);
+ break;
+ case InitialMarkGC:
+ _initial_mark_to_mixed.record_initial_mark_end(end);
+ break;
+ case MixedGC:
+ _initial_mark_to_mixed.record_mixed_gc_start(start);
+ break;
+ default:
+ ShouldNotReachHere();
+ }
+}
+
+void G1Policy::abort_time_to_mixed_tracking() {
+ _initial_mark_to_mixed.reset();
+}
+
+bool G1Policy::next_gc_should_be_mixed(const char* true_action_str,
+ const char* false_action_str) const {
+ if (cset_chooser()->is_empty()) {
+ log_debug(gc, ergo)("%s (candidate old regions not available)", false_action_str);
+ return false;
+ }
+
+ // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
+ size_t reclaimable_bytes = cset_chooser()->remaining_reclaimable_bytes();
+ double reclaimable_percent = reclaimable_bytes_percent(reclaimable_bytes);
+ double threshold = (double) G1HeapWastePercent;
+ if (reclaimable_percent <= threshold) {
+ log_debug(gc, ergo)("%s (reclaimable percentage not over threshold). candidate old regions: %u reclaimable: " SIZE_FORMAT " (%1.2f) threshold: " UINTX_FORMAT,
+ false_action_str, cset_chooser()->remaining_regions(), reclaimable_bytes, reclaimable_percent, G1HeapWastePercent);
+ return false;
+ }
+ log_debug(gc, ergo)("%s (candidate old regions available). candidate old regions: %u reclaimable: " SIZE_FORMAT " (%1.2f) threshold: " UINTX_FORMAT,
+ true_action_str, cset_chooser()->remaining_regions(), reclaimable_bytes, reclaimable_percent, G1HeapWastePercent);
+ return true;
+}
+
+uint G1Policy::calc_min_old_cset_length() const {
+ // The min old CSet region bound is based on the maximum desired
+ // number of mixed GCs after a cycle. I.e., even if some old regions
+ // look expensive, we should add them to the CSet anyway to make
+ // sure we go through the available old regions in no more than the
+ // maximum desired number of mixed GCs.
+ //
+ // The calculation is based on the number of marked regions we added
+ // to the CSet chooser in the first place, not how many remain, so
+ // that the result is the same during all mixed GCs that follow a cycle.
+
+ const size_t region_num = (size_t) cset_chooser()->length();
+ const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
+ size_t result = region_num / gc_num;
+ // emulate ceiling
+ if (result * gc_num < region_num) {
+ result += 1;
+ }
+ return (uint) result;
+}
+
+uint G1Policy::calc_max_old_cset_length() const {
+ // The max old CSet region bound is based on the threshold expressed
+ // as a percentage of the heap size. I.e., it should bound the
+ // number of old regions added to the CSet irrespective of how many
+ // of them are available.
+
+ const G1CollectedHeap* g1h = G1CollectedHeap::heap();
+ const size_t region_num = g1h->num_regions();
+ const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
+ size_t result = region_num * perc / 100;
+ // emulate ceiling
+ if (100 * result < region_num * perc) {
+ result += 1;
+ }
+ return (uint) result;
+}
+
+void G1Policy::finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor) {
+ double time_remaining_ms = _collection_set->finalize_young_part(target_pause_time_ms, survivor);
+ _collection_set->finalize_old_part(time_remaining_ms);
+}
+
+void G1Policy::transfer_survivors_to_cset(const G1SurvivorRegions* survivors) {
+
+ // Add survivor regions to SurvRateGroup.
+ note_start_adding_survivor_regions();
+ finished_recalculating_age_indexes(true /* is_survivors */);
+
+ HeapRegion* last = NULL;
+ for (GrowableArrayIterator<HeapRegion*> it = survivors->regions()->begin();
+ it != survivors->regions()->end();
+ ++it) {
+ HeapRegion* curr = *it;
+ set_region_survivor(curr);
+
+ // The region is a non-empty survivor so let's add it to
+ // the incremental collection set for the next evacuation
+ // pause.
+ _collection_set->add_survivor_regions(curr);
+
+ last = curr;
+ }
+ note_stop_adding_survivor_regions();
+
+ // Don't clear the survivor list handles until the start of
+ // the next evacuation pause - we need it in order to re-tag
+ // the survivor regions from this evacuation pause as 'young'
+ // at the start of the next.
+
+ finished_recalculating_age_indexes(false /* is_survivors */);
+}
--- a/src/hotspot/share/gc/g1/g1Policy.hpp Mon Mar 12 08:16:48 2018 +0100
+++ b/src/hotspot/share/gc/g1/g1Policy.hpp Mon Mar 12 09:46:12 2018 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2018, 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
@@ -47,108 +47,309 @@
class G1Analytics;
class G1SurvivorRegions;
class G1YoungGenSizer;
+class GCPolicyCounters;
+class STWGCTimer;
class G1Policy: public CHeapObj<mtGC> {
+ private:
+
+ static G1IHOPControl* create_ihop_control(const G1Predictions* predictor);
+ // Update the IHOP control with necessary statistics.
+ void update_ihop_prediction(double mutator_time_s,
+ size_t mutator_alloc_bytes,
+ size_t young_gen_size);
+ void report_ihop_statistics();
+
+ G1Predictions _predictor;
+ G1Analytics* _analytics;
+ G1MMUTracker* _mmu_tracker;
+ G1IHOPControl* _ihop_control;
+
+ GCPolicyCounters* _policy_counters;
+
+ double _full_collection_start_sec;
+
+ jlong _collection_pause_end_millis;
+
+ uint _young_list_target_length;
+ uint _young_list_fixed_length;
+
+ // The max number of regions we can extend the eden by while the GC
+ // locker is active. This should be >= _young_list_target_length;
+ uint _young_list_max_length;
+
+ // SurvRateGroups below must be initialized after the predictor because they
+ // indirectly use it through this object passed to their constructor.
+ SurvRateGroup* _short_lived_surv_rate_group;
+ SurvRateGroup* _survivor_surv_rate_group;
+
+ double _reserve_factor;
+ // This will be set when the heap is expanded
+ // for the first time during initialization.
+ uint _reserve_regions;
+
+ G1YoungGenSizer _young_gen_sizer;
+
+ uint _free_regions_at_end_of_collection;
+
+ size_t _max_rs_lengths;
+
+ size_t _rs_lengths_prediction;
+
+ size_t _pending_cards;
+
+ // The amount of allocated bytes in old gen during the last mutator and the following
+ // young GC phase.
+ size_t _bytes_allocated_in_old_since_last_gc;
+
+ G1InitialMarkToMixedTimeTracker _initial_mark_to_mixed;
public:
- virtual const G1Predictions& predictor() const = 0;
- virtual const G1Analytics* analytics() const = 0;
+ const G1Predictions& predictor() const { return _predictor; }
+ const G1Analytics* analytics() const { return const_cast<const G1Analytics*>(_analytics); }
// Add the given number of bytes to the total number of allocated bytes in the old gen.
- virtual void add_bytes_allocated_in_old_since_last_gc(size_t bytes) = 0;
+ void add_bytes_allocated_in_old_since_last_gc(size_t bytes) { _bytes_allocated_in_old_since_last_gc += bytes; }
+
+ void set_region_eden(HeapRegion* hr) {
+ hr->set_eden();
+ hr->install_surv_rate_group(_short_lived_surv_rate_group);
+ }
+
+ void set_region_survivor(HeapRegion* hr) {
+ assert(hr->is_survivor(), "pre-condition");
+ hr->install_surv_rate_group(_survivor_surv_rate_group);
+ }
- // Accessors
+ void record_max_rs_lengths(size_t rs_lengths) {
+ _max_rs_lengths = rs_lengths;
+ }
+
+ double predict_base_elapsed_time_ms(size_t pending_cards) const;
+ double predict_base_elapsed_time_ms(size_t pending_cards,
+ size_t scanned_cards) const;
+ size_t predict_bytes_to_copy(HeapRegion* hr) const;
+ double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const;
+
+ double predict_survivor_regions_evac_time() const;
+
+ bool should_update_surv_rate_group_predictors() {
+ return collector_state()->last_gc_was_young() && !collector_state()->in_marking_window();
+ }
+
+ void cset_regions_freed() {
+ bool update = should_update_surv_rate_group_predictors();
- virtual void set_region_eden(HeapRegion* hr) = 0;
- virtual void set_region_survivor(HeapRegion* hr) = 0;
+ _short_lived_surv_rate_group->all_surviving_words_recorded(predictor(), update);
+ _survivor_surv_rate_group->all_surviving_words_recorded(predictor(), update);
+ }
+
+ G1MMUTracker* mmu_tracker() {
+ return _mmu_tracker;
+ }
+
+ const G1MMUTracker* mmu_tracker() const {
+ return _mmu_tracker;
+ }
+
+ double max_pause_time_ms() const {
+ return _mmu_tracker->max_gc_time() * 1000.0;
+ }
- virtual void record_max_rs_lengths(size_t rs_lengths) = 0;
+ double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const;
+
+ double predict_yg_surv_rate(int age) const;
+
+ double accum_yg_surv_rate_pred(int age) const;
+
+protected:
+ G1CollectionSet* _collection_set;
+ double average_time_ms(G1GCPhaseTimes::GCParPhases phase) const;
+ double other_time_ms(double pause_time_ms) const;
+
+ double young_other_time_ms() const;
+ double non_young_other_time_ms() const;
+ double constant_other_time_ms(double pause_time_ms) const;
+
+ CollectionSetChooser* cset_chooser() const;
+private:
- virtual double predict_base_elapsed_time_ms(size_t pending_cards) const = 0;
- virtual double predict_base_elapsed_time_ms(size_t pending_cards,
- size_t scanned_cards) const = 0;
+ // The number of bytes copied during the GC.
+ size_t _bytes_copied_during_gc;
+
+ // Stash a pointer to the g1 heap.
+ G1CollectedHeap* _g1;
+
+ G1GCPhaseTimes* _phase_times;
+
+ // This set of variables tracks the collector efficiency, in order to
+ // determine whether we should initiate a new marking.
+ double _mark_remark_start_sec;
+ double _mark_cleanup_start_sec;
- virtual double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc) const = 0;
+ // Updates the internal young list maximum and target lengths. Returns the
+ // unbounded young list target length.
+ uint update_young_list_max_and_target_length();
+ uint update_young_list_max_and_target_length(size_t rs_lengths);
- virtual void cset_regions_freed() = 0;
+ // Update the young list target length either by setting it to the
+ // desired fixed value or by calculating it using G1's pause
+ // prediction model. If no rs_lengths parameter is passed, predict
+ // the RS lengths using the prediction model, otherwise use the
+ // given rs_lengths as the prediction.
+ // Returns the unbounded young list target length.
+ uint update_young_list_target_length(size_t rs_lengths);
+
+ // Calculate and return the minimum desired young list target
+ // length. This is the minimum desired young list length according
+ // to the user's inputs.
+ uint calculate_young_list_desired_min_length(uint base_min_length) const;
- virtual G1MMUTracker* mmu_tracker() = 0;
+ // Calculate and return the maximum desired young list target
+ // length. This is the maximum desired young list length according
+ // to the user's inputs.
+ uint calculate_young_list_desired_max_length() const;
- virtual const G1MMUTracker* mmu_tracker() const = 0;
+ // Calculate and return the maximum young list target length that
+ // can fit into the pause time goal. The parameters are: rs_lengths
+ // represent the prediction of how large the young RSet lengths will
+ // be, base_min_length is the already existing number of regions in
+ // the young list, min_length and max_length are the desired min and
+ // max young list length according to the user's inputs.
+ uint calculate_young_list_target_length(size_t rs_lengths,
+ uint base_min_length,
+ uint desired_min_length,
+ uint desired_max_length) const;
- virtual double max_pause_time_ms() const = 0;
+ // Result of the bounded_young_list_target_length() method, containing both the
+ // bounded as well as the unbounded young list target lengths in this order.
+ typedef Pair<uint, uint, StackObj> YoungTargetLengths;
+ YoungTargetLengths young_list_target_lengths(size_t rs_lengths) const;
+
+ void update_rs_lengths_prediction();
+ void update_rs_lengths_prediction(size_t prediction);
- virtual size_t pending_cards() const = 0;
+ // Check whether a given young length (young_length) fits into the
+ // given target pause time and whether the prediction for the amount
+ // of objects to be copied for the given length will fit into the
+ // given free space (expressed by base_free_regions). It is used by
+ // calculate_young_list_target_length().
+ bool predict_will_fit(uint young_length, double base_time_ms,
+ uint base_free_regions, double target_pause_time_ms) const;
+
+public:
+ size_t pending_cards() const { return _pending_cards; }
// Calculate the minimum number of old regions we'll add to the CSet
// during a mixed GC.
- virtual uint calc_min_old_cset_length() const = 0;
+ uint calc_min_old_cset_length() const;
// Calculate the maximum number of old regions we'll add to the CSet
// during a mixed GC.
- virtual uint calc_max_old_cset_length() const = 0;
+ uint calc_max_old_cset_length() const;
- // Returns the given amount of uncollected reclaimable space
- // as a percentage of the current heap capacity.
- virtual double reclaimable_bytes_percent(size_t reclaimable_bytes) const = 0;
+ // Returns the given amount of reclaimable bytes (that represents
+ // the amount of reclaimable space still to be collected) as a
+ // percentage of the current heap capacity.
+ double reclaimable_bytes_percent(size_t reclaimable_bytes) const;
+
+ jlong collection_pause_end_millis() { return _collection_pause_end_millis; }
+
+private:
+ // Sets up marking if proper conditions are met.
+ void maybe_start_marking();
- virtual ~G1Policy() {}
+ // The kind of STW pause.
+ enum PauseKind {
+ FullGC,
+ YoungOnlyGC,
+ MixedGC,
+ LastYoungGC,
+ InitialMarkGC,
+ Cleanup,
+ Remark
+ };
- virtual G1CollectorState* collector_state() const = 0;
+ // Calculate PauseKind from internal state.
+ PauseKind young_gc_pause_kind() const;
+ // Record the given STW pause with the given start and end times (in s).
+ void record_pause(PauseKind kind, double start, double end);
+ // Indicate that we aborted marking before doing any mixed GCs.
+ void abort_time_to_mixed_tracking();
+public:
- virtual G1GCPhaseTimes* phase_times() const = 0;
+ G1Policy(STWGCTimer* gc_timer);
+
+ virtual ~G1Policy();
+
+ G1CollectorState* collector_state() const;
+
+ G1GCPhaseTimes* phase_times() const { return _phase_times; }
// Check the current value of the young list RSet lengths and
// compare it against the last prediction. If the current value is
// higher, recalculate the young list target length prediction.
- virtual void revise_young_list_target_length_if_necessary(size_t rs_lengths) = 0;
+ void revise_young_list_target_length_if_necessary(size_t rs_lengths);
// This should be called after the heap is resized.
- virtual void record_new_heap_size(uint new_number_of_regions) = 0;
+ void record_new_heap_size(uint new_number_of_regions);
- virtual void init(G1CollectedHeap* g1h, G1CollectionSet* collection_set) = 0;
+ void init(G1CollectedHeap* g1h, G1CollectionSet* collection_set);
- virtual void note_gc_start() = 0;
+ void note_gc_start();
- virtual bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0) = 0;
+ bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
+
+ bool about_to_start_mixed_phase() const;
// Record the start and end of an evacuation pause.
- virtual void record_collection_pause_start(double start_time_sec) = 0;
- virtual void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc) = 0;
+ void record_collection_pause_start(double start_time_sec);
+ void record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc);
// Record the start and end of a full collection.
- virtual void record_full_collection_start() = 0;
- virtual void record_full_collection_end() = 0;
-
- virtual jlong collection_pause_end_millis() = 0;
+ void record_full_collection_start();
+ void record_full_collection_end();
// Must currently be called while the world is stopped.
- virtual void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms) = 0;
+ void record_concurrent_mark_init_end(double mark_init_elapsed_time_ms);
// Record start and end of remark.
- virtual void record_concurrent_mark_remark_start() = 0;
- virtual void record_concurrent_mark_remark_end() = 0;
+ void record_concurrent_mark_remark_start();
+ void record_concurrent_mark_remark_end();
// Record start, end, and completion of cleanup.
- virtual void record_concurrent_mark_cleanup_start() = 0;
- virtual void record_concurrent_mark_cleanup_end() = 0;
- virtual void record_concurrent_mark_cleanup_completed() = 0;
+ void record_concurrent_mark_cleanup_start();
+ void record_concurrent_mark_cleanup_end();
+ void record_concurrent_mark_cleanup_completed();
- virtual void print_phases() = 0;
+ void print_phases();
// Record how much space we copied during a GC. This is typically
// called when a GC alloc region is being retired.
- virtual void record_bytes_copied_during_gc(size_t bytes) = 0;
+ void record_bytes_copied_during_gc(size_t bytes) {
+ _bytes_copied_during_gc += bytes;
+ }
// The amount of space we copied during a GC.
- virtual size_t bytes_copied_during_gc() const = 0;
+ size_t bytes_copied_during_gc() const {
+ return _bytes_copied_during_gc;
+ }
+
+ bool next_gc_should_be_mixed(const char* true_action_str,
+ const char* false_action_str) const;
- virtual void finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor) = 0;
+ void finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor);
+private:
+ // Set the state to start a concurrent marking cycle and clear
+ // _initiate_conc_mark_if_possible because it has now been
+ // acted on.
+ void initiate_conc_mark();
+public:
// This sets the initiate_conc_mark_if_possible() flag to start a
// new cycle, as long as we are not already in one. It's best if it
// is called during a safepoint when the test whether a cycle is in
// progress or not is stable.
- virtual bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause) = 0;
+ bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
// This is called at the very beginning of an evacuation pause (it
// has to be the first thing that the pause does). If
@@ -156,36 +357,74 @@
// marking thread has completed its work during the previous cycle,
// it will set during_initial_mark_pause() to so that the pause does
// the initial-mark work and start a marking cycle.
- virtual void decide_on_conc_mark_initiation() = 0;
-
+ void decide_on_conc_mark_initiation();
- virtual void finished_recalculating_age_indexes(bool is_survivors) = 0;
+ void finished_recalculating_age_indexes(bool is_survivors) {
+ if (is_survivors) {
+ _survivor_surv_rate_group->finished_recalculating_age_indexes();
+ } else {
+ _short_lived_surv_rate_group->finished_recalculating_age_indexes();
+ }
+ }
- virtual void transfer_survivors_to_cset(const G1SurvivorRegions* survivors) = 0;
+ size_t young_list_target_length() const { return _young_list_target_length; }
+
+ bool should_allocate_mutator_region() const;
+
+ bool can_expand_young_list() const;
- virtual size_t young_list_target_length() const = 0;
+ uint young_list_max_length() const {
+ return _young_list_max_length;
+ }
- virtual bool should_allocate_mutator_region() const = 0;
+ bool adaptive_young_list_length() const;
- virtual bool can_expand_young_list() const = 0;
+ bool should_process_references() const {
+ return true;
+ }
- virtual uint young_list_max_length() const = 0;
+ void transfer_survivors_to_cset(const G1SurvivorRegions* survivors);
+
+private:
+ //
+ // Survivor regions policy.
+ //
- virtual bool adaptive_young_list_length() const = 0;
+ // Current tenuring threshold, set to 0 if the collector reaches the
+ // maximum amount of survivors regions.
+ uint _tenuring_threshold;
+
+ // The limit on the number of regions allocated for survivors.
+ uint _max_survivor_regions;
+
+ AgeTable _survivors_age_table;
- virtual bool should_process_references() const = 0;
+protected:
+ size_t desired_survivor_size() const;
+public:
+ uint tenuring_threshold() const { return _tenuring_threshold; }
- virtual uint tenuring_threshold() const = 0;
- virtual uint max_survivor_regions() = 0;
+ uint max_survivor_regions() {
+ return _max_survivor_regions;
+ }
- virtual void note_start_adding_survivor_regions() = 0;
+ void note_start_adding_survivor_regions() {
+ _survivor_surv_rate_group->start_adding_regions();
+ }
- virtual void note_stop_adding_survivor_regions() = 0;
+ void note_stop_adding_survivor_regions() {
+ _survivor_surv_rate_group->stop_adding_regions();
+ }
- virtual void record_age_table(AgeTable* age_table) = 0;
- virtual void print_age_table() = 0;
-protected:
- virtual size_t desired_survivor_size() const = 0;
+ void record_age_table(AgeTable* age_table) {
+ _survivors_age_table.merge(age_table);
+ }
+
+ void print_age_table();
+
+ void update_max_gc_locker_expansion();
+
+ void update_survivors_policy();
};
#endif // SHARE_VM_GC_G1_G1POLICY_HPP