1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,2280 @@
1.4 +/*
1.5 + * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef __clang_major__
1.29 +#define ATTRIBUTE_PRINTF(x,y) // FIXME, formats are a mess.
1.30 +#endif
1.31 +
1.32 +#include "precompiled.hpp"
1.33 +#include "gc_implementation/g1/concurrentG1Refine.hpp"
1.34 +#include "gc_implementation/g1/concurrentMark.hpp"
1.35 +#include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
1.36 +#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
1.37 +#include "gc_implementation/g1/g1CollectorPolicy.hpp"
1.38 +#include "gc_implementation/g1/g1ErgoVerbose.hpp"
1.39 +#include "gc_implementation/g1/g1GCPhaseTimes.hpp"
1.40 +#include "gc_implementation/g1/g1Log.hpp"
1.41 +#include "gc_implementation/g1/heapRegionRemSet.hpp"
1.42 +#include "gc_implementation/shared/gcPolicyCounters.hpp"
1.43 +#include "runtime/arguments.hpp"
1.44 +#include "runtime/java.hpp"
1.45 +#include "runtime/mutexLocker.hpp"
1.46 +#include "utilities/debug.hpp"
1.47 +
1.48 +// Different defaults for different number of GC threads
1.49 +// They were chosen by running GCOld and SPECjbb on debris with different
1.50 +// numbers of GC threads and choosing them based on the results
1.51 +
1.52 +// all the same
1.53 +static double rs_length_diff_defaults[] = {
1.54 + 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
1.55 +};
1.56 +
1.57 +static double cost_per_card_ms_defaults[] = {
1.58 + 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
1.59 +};
1.60 +
1.61 +// all the same
1.62 +static double young_cards_per_entry_ratio_defaults[] = {
1.63 + 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
1.64 +};
1.65 +
1.66 +static double cost_per_entry_ms_defaults[] = {
1.67 + 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
1.68 +};
1.69 +
1.70 +static double cost_per_byte_ms_defaults[] = {
1.71 + 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
1.72 +};
1.73 +
1.74 +// these should be pretty consistent
1.75 +static double constant_other_time_ms_defaults[] = {
1.76 + 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
1.77 +};
1.78 +
1.79 +
1.80 +static double young_other_cost_per_region_ms_defaults[] = {
1.81 + 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
1.82 +};
1.83 +
1.84 +static double non_young_other_cost_per_region_ms_defaults[] = {
1.85 + 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
1.86 +};
1.87 +
1.88 +G1CollectorPolicy::G1CollectorPolicy() :
1.89 + _parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads()
1.90 + ? ParallelGCThreads : 1),
1.91 +
1.92 + _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
1.93 + _stop_world_start(0.0),
1.94 +
1.95 + _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
1.96 + _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
1.97 +
1.98 + _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
1.99 + _prev_collection_pause_end_ms(0.0),
1.100 + _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
1.101 + _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
1.102 + _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
1.103 + _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
1.104 + _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
1.105 + _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
1.106 + _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
1.107 + _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
1.108 + _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
1.109 + _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
1.110 + _non_young_other_cost_per_region_ms_seq(
1.111 + new TruncatedSeq(TruncatedSeqLength)),
1.112 +
1.113 + _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
1.114 + _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
1.115 +
1.116 + _pause_time_target_ms((double) MaxGCPauseMillis),
1.117 +
1.118 + _gcs_are_young(true),
1.119 +
1.120 + _during_marking(false),
1.121 + _in_marking_window(false),
1.122 + _in_marking_window_im(false),
1.123 +
1.124 + _recent_prev_end_times_for_all_gcs_sec(
1.125 + new TruncatedSeq(NumPrevPausesForHeuristics)),
1.126 +
1.127 + _recent_avg_pause_time_ratio(0.0),
1.128 +
1.129 + _initiate_conc_mark_if_possible(false),
1.130 + _during_initial_mark_pause(false),
1.131 + _last_young_gc(false),
1.132 + _last_gc_was_young(false),
1.133 +
1.134 + _eden_used_bytes_before_gc(0),
1.135 + _survivor_used_bytes_before_gc(0),
1.136 + _heap_used_bytes_before_gc(0),
1.137 + _metaspace_used_bytes_before_gc(0),
1.138 + _eden_capacity_bytes_before_gc(0),
1.139 + _heap_capacity_bytes_before_gc(0),
1.140 +
1.141 + _eden_cset_region_length(0),
1.142 + _survivor_cset_region_length(0),
1.143 + _old_cset_region_length(0),
1.144 +
1.145 + _collection_set(NULL),
1.146 + _collection_set_bytes_used_before(0),
1.147 +
1.148 + // Incremental CSet attributes
1.149 + _inc_cset_build_state(Inactive),
1.150 + _inc_cset_head(NULL),
1.151 + _inc_cset_tail(NULL),
1.152 + _inc_cset_bytes_used_before(0),
1.153 + _inc_cset_max_finger(NULL),
1.154 + _inc_cset_recorded_rs_lengths(0),
1.155 + _inc_cset_recorded_rs_lengths_diffs(0),
1.156 + _inc_cset_predicted_elapsed_time_ms(0.0),
1.157 + _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
1.158 +
1.159 +#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
1.160 +#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
1.161 +#endif // _MSC_VER
1.162 +
1.163 + _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
1.164 + G1YoungSurvRateNumRegionsSummary)),
1.165 + _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
1.166 + G1YoungSurvRateNumRegionsSummary)),
1.167 + // add here any more surv rate groups
1.168 + _recorded_survivor_regions(0),
1.169 + _recorded_survivor_head(NULL),
1.170 + _recorded_survivor_tail(NULL),
1.171 + _survivors_age_table(true),
1.172 +
1.173 + _gc_overhead_perc(0.0) {
1.174 +
1.175 + // Set up the region size and associated fields. Given that the
1.176 + // policy is created before the heap, we have to set this up here,
1.177 + // so it's done as soon as possible.
1.178 +
1.179 + // It would have been natural to pass initial_heap_byte_size() and
1.180 + // max_heap_byte_size() to setup_heap_region_size() but those have
1.181 + // not been set up at this point since they should be aligned with
1.182 + // the region size. So, there is a circular dependency here. We base
1.183 + // the region size on the heap size, but the heap size should be
1.184 + // aligned with the region size. To get around this we use the
1.185 + // unaligned values for the heap.
1.186 + HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
1.187 + HeapRegionRemSet::setup_remset_size();
1.188 +
1.189 + G1ErgoVerbose::initialize();
1.190 + if (PrintAdaptiveSizePolicy) {
1.191 + // Currently, we only use a single switch for all the heuristics.
1.192 + G1ErgoVerbose::set_enabled(true);
1.193 + // Given that we don't currently have a verboseness level
1.194 + // parameter, we'll hardcode this to high. This can be easily
1.195 + // changed in the future.
1.196 + G1ErgoVerbose::set_level(ErgoHigh);
1.197 + } else {
1.198 + G1ErgoVerbose::set_enabled(false);
1.199 + }
1.200 +
1.201 + // Verify PLAB sizes
1.202 + const size_t region_size = HeapRegion::GrainWords;
1.203 + if (YoungPLABSize > region_size || OldPLABSize > region_size) {
1.204 + char buffer[128];
1.205 + jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT,
1.206 + OldPLABSize > region_size ? "Old" : "Young", region_size);
1.207 + vm_exit_during_initialization(buffer);
1.208 + }
1.209 +
1.210 + _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
1.211 + _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
1.212 +
1.213 + _phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
1.214 +
1.215 + int index = MIN2(_parallel_gc_threads - 1, 7);
1.216 +
1.217 + _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
1.218 + _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
1.219 + _young_cards_per_entry_ratio_seq->add(
1.220 + young_cards_per_entry_ratio_defaults[index]);
1.221 + _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
1.222 + _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
1.223 + _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
1.224 + _young_other_cost_per_region_ms_seq->add(
1.225 + young_other_cost_per_region_ms_defaults[index]);
1.226 + _non_young_other_cost_per_region_ms_seq->add(
1.227 + non_young_other_cost_per_region_ms_defaults[index]);
1.228 +
1.229 + // Below, we might need to calculate the pause time target based on
1.230 + // the pause interval. When we do so we are going to give G1 maximum
1.231 + // flexibility and allow it to do pauses when it needs to. So, we'll
1.232 + // arrange that the pause interval to be pause time target + 1 to
1.233 + // ensure that a) the pause time target is maximized with respect to
1.234 + // the pause interval and b) we maintain the invariant that pause
1.235 + // time target < pause interval. If the user does not want this
1.236 + // maximum flexibility, they will have to set the pause interval
1.237 + // explicitly.
1.238 +
1.239 + // First make sure that, if either parameter is set, its value is
1.240 + // reasonable.
1.241 + if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
1.242 + if (MaxGCPauseMillis < 1) {
1.243 + vm_exit_during_initialization("MaxGCPauseMillis should be "
1.244 + "greater than 0");
1.245 + }
1.246 + }
1.247 + if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
1.248 + if (GCPauseIntervalMillis < 1) {
1.249 + vm_exit_during_initialization("GCPauseIntervalMillis should be "
1.250 + "greater than 0");
1.251 + }
1.252 + }
1.253 +
1.254 + // Then, if the pause time target parameter was not set, set it to
1.255 + // the default value.
1.256 + if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
1.257 + if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
1.258 + // The default pause time target in G1 is 200ms
1.259 + FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
1.260 + } else {
1.261 + // We do not allow the pause interval to be set without the
1.262 + // pause time target
1.263 + vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
1.264 + "without setting MaxGCPauseMillis");
1.265 + }
1.266 + }
1.267 +
1.268 + // Then, if the interval parameter was not set, set it according to
1.269 + // the pause time target (this will also deal with the case when the
1.270 + // pause time target is the default value).
1.271 + if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
1.272 + FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
1.273 + }
1.274 +
1.275 + // Finally, make sure that the two parameters are consistent.
1.276 + if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
1.277 + char buffer[256];
1.278 + jio_snprintf(buffer, 256,
1.279 + "MaxGCPauseMillis (%u) should be less than "
1.280 + "GCPauseIntervalMillis (%u)",
1.281 + MaxGCPauseMillis, GCPauseIntervalMillis);
1.282 + vm_exit_during_initialization(buffer);
1.283 + }
1.284 +
1.285 + double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
1.286 + double time_slice = (double) GCPauseIntervalMillis / 1000.0;
1.287 + _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
1.288 +
1.289 + uintx confidence_perc = G1ConfidencePercent;
1.290 + // Put an artificial ceiling on this so that it's not set to a silly value.
1.291 + if (confidence_perc > 100) {
1.292 + confidence_perc = 100;
1.293 + warning("G1ConfidencePercent is set to a value that is too large, "
1.294 + "it's been updated to %u", confidence_perc);
1.295 + }
1.296 + _sigma = (double) confidence_perc / 100.0;
1.297 +
1.298 + // start conservatively (around 50ms is about right)
1.299 + _concurrent_mark_remark_times_ms->add(0.05);
1.300 + _concurrent_mark_cleanup_times_ms->add(0.20);
1.301 + _tenuring_threshold = MaxTenuringThreshold;
1.302 + // _max_survivor_regions will be calculated by
1.303 + // update_young_list_target_length() during initialization.
1.304 + _max_survivor_regions = 0;
1.305 +
1.306 + assert(GCTimeRatio > 0,
1.307 + "we should have set it to a default value set_g1_gc_flags() "
1.308 + "if a user set it to 0");
1.309 + _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
1.310 +
1.311 + uintx reserve_perc = G1ReservePercent;
1.312 + // Put an artificial ceiling on this so that it's not set to a silly value.
1.313 + if (reserve_perc > 50) {
1.314 + reserve_perc = 50;
1.315 + warning("G1ReservePercent is set to a value that is too large, "
1.316 + "it's been updated to %u", reserve_perc);
1.317 + }
1.318 + _reserve_factor = (double) reserve_perc / 100.0;
1.319 + // This will be set when the heap is expanded
1.320 + // for the first time during initialization.
1.321 + _reserve_regions = 0;
1.322 +
1.323 + _collectionSetChooser = new CollectionSetChooser();
1.324 +}
1.325 +
1.326 +void G1CollectorPolicy::initialize_alignments() {
1.327 + _space_alignment = HeapRegion::GrainBytes;
1.328 + size_t card_table_alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
1.329 + size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
1.330 + _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
1.331 +}
1.332 +
1.333 +void G1CollectorPolicy::initialize_flags() {
1.334 + if (G1HeapRegionSize != HeapRegion::GrainBytes) {
1.335 + FLAG_SET_ERGO(uintx, G1HeapRegionSize, HeapRegion::GrainBytes);
1.336 + }
1.337 +
1.338 + if (SurvivorRatio < 1) {
1.339 + vm_exit_during_initialization("Invalid survivor ratio specified");
1.340 + }
1.341 + CollectorPolicy::initialize_flags();
1.342 + _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
1.343 +}
1.344 +
1.345 +void G1CollectorPolicy::post_heap_initialize() {
1.346 + uintx max_regions = G1CollectedHeap::heap()->max_regions();
1.347 + size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
1.348 + if (max_young_size != MaxNewSize) {
1.349 + FLAG_SET_ERGO(uintx, MaxNewSize, max_young_size);
1.350 + }
1.351 +}
1.352 +
1.353 +G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
1.354 + _min_desired_young_length(0), _max_desired_young_length(0) {
1.355 + if (FLAG_IS_CMDLINE(NewRatio)) {
1.356 + if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
1.357 + warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
1.358 + } else {
1.359 + _sizer_kind = SizerNewRatio;
1.360 + _adaptive_size = false;
1.361 + return;
1.362 + }
1.363 + }
1.364 +
1.365 + if (NewSize > MaxNewSize) {
1.366 + if (FLAG_IS_CMDLINE(MaxNewSize)) {
1.367 + warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
1.368 + "A new max generation size of " SIZE_FORMAT "k will be used.",
1.369 + NewSize/K, MaxNewSize/K, NewSize/K);
1.370 + }
1.371 + MaxNewSize = NewSize;
1.372 + }
1.373 +
1.374 + if (FLAG_IS_CMDLINE(NewSize)) {
1.375 + _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
1.376 + 1U);
1.377 + if (FLAG_IS_CMDLINE(MaxNewSize)) {
1.378 + _max_desired_young_length =
1.379 + MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
1.380 + 1U);
1.381 + _sizer_kind = SizerMaxAndNewSize;
1.382 + _adaptive_size = _min_desired_young_length == _max_desired_young_length;
1.383 + } else {
1.384 + _sizer_kind = SizerNewSizeOnly;
1.385 + }
1.386 + } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
1.387 + _max_desired_young_length =
1.388 + MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
1.389 + 1U);
1.390 + _sizer_kind = SizerMaxNewSizeOnly;
1.391 + }
1.392 +}
1.393 +
1.394 +uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
1.395 + uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
1.396 + return MAX2(1U, default_value);
1.397 +}
1.398 +
1.399 +uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
1.400 + uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
1.401 + return MAX2(1U, default_value);
1.402 +}
1.403 +
1.404 +void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
1.405 + assert(number_of_heap_regions > 0, "Heap must be initialized");
1.406 +
1.407 + switch (_sizer_kind) {
1.408 + case SizerDefaults:
1.409 + *min_young_length = calculate_default_min_length(number_of_heap_regions);
1.410 + *max_young_length = calculate_default_max_length(number_of_heap_regions);
1.411 + break;
1.412 + case SizerNewSizeOnly:
1.413 + *max_young_length = calculate_default_max_length(number_of_heap_regions);
1.414 + *max_young_length = MAX2(*min_young_length, *max_young_length);
1.415 + break;
1.416 + case SizerMaxNewSizeOnly:
1.417 + *min_young_length = calculate_default_min_length(number_of_heap_regions);
1.418 + *min_young_length = MIN2(*min_young_length, *max_young_length);
1.419 + break;
1.420 + case SizerMaxAndNewSize:
1.421 + // Do nothing. Values set on the command line, don't update them at runtime.
1.422 + break;
1.423 + case SizerNewRatio:
1.424 + *min_young_length = number_of_heap_regions / (NewRatio + 1);
1.425 + *max_young_length = *min_young_length;
1.426 + break;
1.427 + default:
1.428 + ShouldNotReachHere();
1.429 + }
1.430 +
1.431 + assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
1.432 +}
1.433 +
1.434 +uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
1.435 + // We need to pass the desired values because recalculation may not update these
1.436 + // values in some cases.
1.437 + uint temp = _min_desired_young_length;
1.438 + uint result = _max_desired_young_length;
1.439 + recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
1.440 + return result;
1.441 +}
1.442 +
1.443 +void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
1.444 + recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
1.445 + &_max_desired_young_length);
1.446 +}
1.447 +
1.448 +void G1CollectorPolicy::init() {
1.449 + // Set aside an initial future to_space.
1.450 + _g1 = G1CollectedHeap::heap();
1.451 +
1.452 + assert(Heap_lock->owned_by_self(), "Locking discipline.");
1.453 +
1.454 + initialize_gc_policy_counters();
1.455 +
1.456 + if (adaptive_young_list_length()) {
1.457 + _young_list_fixed_length = 0;
1.458 + } else {
1.459 + _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
1.460 + }
1.461 + _free_regions_at_end_of_collection = _g1->free_regions();
1.462 + update_young_list_target_length();
1.463 +
1.464 + // We may immediately start allocating regions and placing them on the
1.465 + // collection set list. Initialize the per-collection set info
1.466 + start_incremental_cset_building();
1.467 +}
1.468 +
1.469 +// Create the jstat counters for the policy.
1.470 +void G1CollectorPolicy::initialize_gc_policy_counters() {
1.471 + _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
1.472 +}
1.473 +
1.474 +bool G1CollectorPolicy::predict_will_fit(uint young_length,
1.475 + double base_time_ms,
1.476 + uint base_free_regions,
1.477 + double target_pause_time_ms) {
1.478 + if (young_length >= base_free_regions) {
1.479 + // end condition 1: not enough space for the young regions
1.480 + return false;
1.481 + }
1.482 +
1.483 + double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
1.484 + size_t bytes_to_copy =
1.485 + (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
1.486 + double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
1.487 + double young_other_time_ms = predict_young_other_time_ms(young_length);
1.488 + double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
1.489 + if (pause_time_ms > target_pause_time_ms) {
1.490 + // end condition 2: prediction is over the target pause time
1.491 + return false;
1.492 + }
1.493 +
1.494 + size_t free_bytes =
1.495 + (base_free_regions - young_length) * HeapRegion::GrainBytes;
1.496 + if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
1.497 + // end condition 3: out-of-space (conservatively!)
1.498 + return false;
1.499 + }
1.500 +
1.501 + // success!
1.502 + return true;
1.503 +}
1.504 +
1.505 +void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
1.506 + // re-calculate the necessary reserve
1.507 + double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
1.508 + // We use ceiling so that if reserve_regions_d is > 0.0 (but
1.509 + // smaller than 1.0) we'll get 1.
1.510 + _reserve_regions = (uint) ceil(reserve_regions_d);
1.511 +
1.512 + _young_gen_sizer->heap_size_changed(new_number_of_regions);
1.513 +}
1.514 +
1.515 +uint G1CollectorPolicy::calculate_young_list_desired_min_length(
1.516 + uint base_min_length) {
1.517 + uint desired_min_length = 0;
1.518 + if (adaptive_young_list_length()) {
1.519 + if (_alloc_rate_ms_seq->num() > 3) {
1.520 + double now_sec = os::elapsedTime();
1.521 + double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
1.522 + double alloc_rate_ms = predict_alloc_rate_ms();
1.523 + desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
1.524 + } else {
1.525 + // otherwise we don't have enough info to make the prediction
1.526 + }
1.527 + }
1.528 + desired_min_length += base_min_length;
1.529 + // make sure we don't go below any user-defined minimum bound
1.530 + return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
1.531 +}
1.532 +
1.533 +uint G1CollectorPolicy::calculate_young_list_desired_max_length() {
1.534 + // Here, we might want to also take into account any additional
1.535 + // constraints (i.e., user-defined minimum bound). Currently, we
1.536 + // effectively don't set this bound.
1.537 + return _young_gen_sizer->max_desired_young_length();
1.538 +}
1.539 +
1.540 +void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
1.541 + if (rs_lengths == (size_t) -1) {
1.542 + // if it's set to the default value (-1), we should predict it;
1.543 + // otherwise, use the given value.
1.544 + rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
1.545 + }
1.546 +
1.547 + // Calculate the absolute and desired min bounds.
1.548 +
1.549 + // This is how many young regions we already have (currently: the survivors).
1.550 + uint base_min_length = recorded_survivor_regions();
1.551 + // This is the absolute minimum young length, which ensures that we
1.552 + // can allocate one eden region in the worst-case.
1.553 + uint absolute_min_length = base_min_length + 1;
1.554 + uint desired_min_length =
1.555 + calculate_young_list_desired_min_length(base_min_length);
1.556 + if (desired_min_length < absolute_min_length) {
1.557 + desired_min_length = absolute_min_length;
1.558 + }
1.559 +
1.560 + // Calculate the absolute and desired max bounds.
1.561 +
1.562 + // We will try our best not to "eat" into the reserve.
1.563 + uint absolute_max_length = 0;
1.564 + if (_free_regions_at_end_of_collection > _reserve_regions) {
1.565 + absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
1.566 + }
1.567 + uint desired_max_length = calculate_young_list_desired_max_length();
1.568 + if (desired_max_length > absolute_max_length) {
1.569 + desired_max_length = absolute_max_length;
1.570 + }
1.571 +
1.572 + uint young_list_target_length = 0;
1.573 + if (adaptive_young_list_length()) {
1.574 + if (gcs_are_young()) {
1.575 + young_list_target_length =
1.576 + calculate_young_list_target_length(rs_lengths,
1.577 + base_min_length,
1.578 + desired_min_length,
1.579 + desired_max_length);
1.580 + _rs_lengths_prediction = rs_lengths;
1.581 + } else {
1.582 + // Don't calculate anything and let the code below bound it to
1.583 + // the desired_min_length, i.e., do the next GC as soon as
1.584 + // possible to maximize how many old regions we can add to it.
1.585 + }
1.586 + } else {
1.587 + // The user asked for a fixed young gen so we'll fix the young gen
1.588 + // whether the next GC is young or mixed.
1.589 + young_list_target_length = _young_list_fixed_length;
1.590 + }
1.591 +
1.592 + // Make sure we don't go over the desired max length, nor under the
1.593 + // desired min length. In case they clash, desired_min_length wins
1.594 + // which is why that test is second.
1.595 + if (young_list_target_length > desired_max_length) {
1.596 + young_list_target_length = desired_max_length;
1.597 + }
1.598 + if (young_list_target_length < desired_min_length) {
1.599 + young_list_target_length = desired_min_length;
1.600 + }
1.601 +
1.602 + assert(young_list_target_length > recorded_survivor_regions(),
1.603 + "we should be able to allocate at least one eden region");
1.604 + assert(young_list_target_length >= absolute_min_length, "post-condition");
1.605 + _young_list_target_length = young_list_target_length;
1.606 +
1.607 + update_max_gc_locker_expansion();
1.608 +}
1.609 +
1.610 +uint
1.611 +G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
1.612 + uint base_min_length,
1.613 + uint desired_min_length,
1.614 + uint desired_max_length) {
1.615 + assert(adaptive_young_list_length(), "pre-condition");
1.616 + assert(gcs_are_young(), "only call this for young GCs");
1.617 +
1.618 + // In case some edge-condition makes the desired max length too small...
1.619 + if (desired_max_length <= desired_min_length) {
1.620 + return desired_min_length;
1.621 + }
1.622 +
1.623 + // We'll adjust min_young_length and max_young_length not to include
1.624 + // the already allocated young regions (i.e., so they reflect the
1.625 + // min and max eden regions we'll allocate). The base_min_length
1.626 + // will be reflected in the predictions by the
1.627 + // survivor_regions_evac_time prediction.
1.628 + assert(desired_min_length > base_min_length, "invariant");
1.629 + uint min_young_length = desired_min_length - base_min_length;
1.630 + assert(desired_max_length > base_min_length, "invariant");
1.631 + uint max_young_length = desired_max_length - base_min_length;
1.632 +
1.633 + double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
1.634 + double survivor_regions_evac_time = predict_survivor_regions_evac_time();
1.635 + size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
1.636 + size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
1.637 + size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
1.638 + double base_time_ms =
1.639 + predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
1.640 + survivor_regions_evac_time;
1.641 + uint available_free_regions = _free_regions_at_end_of_collection;
1.642 + uint base_free_regions = 0;
1.643 + if (available_free_regions > _reserve_regions) {
1.644 + base_free_regions = available_free_regions - _reserve_regions;
1.645 + }
1.646 +
1.647 + // Here, we will make sure that the shortest young length that
1.648 + // makes sense fits within the target pause time.
1.649 +
1.650 + if (predict_will_fit(min_young_length, base_time_ms,
1.651 + base_free_regions, target_pause_time_ms)) {
1.652 + // The shortest young length will fit into the target pause time;
1.653 + // we'll now check whether the absolute maximum number of young
1.654 + // regions will fit in the target pause time. If not, we'll do
1.655 + // a binary search between min_young_length and max_young_length.
1.656 + if (predict_will_fit(max_young_length, base_time_ms,
1.657 + base_free_regions, target_pause_time_ms)) {
1.658 + // The maximum young length will fit into the target pause time.
1.659 + // We are done so set min young length to the maximum length (as
1.660 + // the result is assumed to be returned in min_young_length).
1.661 + min_young_length = max_young_length;
1.662 + } else {
1.663 + // The maximum possible number of young regions will not fit within
1.664 + // the target pause time so we'll search for the optimal
1.665 + // length. The loop invariants are:
1.666 + //
1.667 + // min_young_length < max_young_length
1.668 + // min_young_length is known to fit into the target pause time
1.669 + // max_young_length is known not to fit into the target pause time
1.670 + //
1.671 + // Going into the loop we know the above hold as we've just
1.672 + // checked them. Every time around the loop we check whether
1.673 + // the middle value between min_young_length and
1.674 + // max_young_length fits into the target pause time. If it
1.675 + // does, it becomes the new min. If it doesn't, it becomes
1.676 + // the new max. This way we maintain the loop invariants.
1.677 +
1.678 + assert(min_young_length < max_young_length, "invariant");
1.679 + uint diff = (max_young_length - min_young_length) / 2;
1.680 + while (diff > 0) {
1.681 + uint young_length = min_young_length + diff;
1.682 + if (predict_will_fit(young_length, base_time_ms,
1.683 + base_free_regions, target_pause_time_ms)) {
1.684 + min_young_length = young_length;
1.685 + } else {
1.686 + max_young_length = young_length;
1.687 + }
1.688 + assert(min_young_length < max_young_length, "invariant");
1.689 + diff = (max_young_length - min_young_length) / 2;
1.690 + }
1.691 + // The results is min_young_length which, according to the
1.692 + // loop invariants, should fit within the target pause time.
1.693 +
1.694 + // These are the post-conditions of the binary search above:
1.695 + assert(min_young_length < max_young_length,
1.696 + "otherwise we should have discovered that max_young_length "
1.697 + "fits into the pause target and not done the binary search");
1.698 + assert(predict_will_fit(min_young_length, base_time_ms,
1.699 + base_free_regions, target_pause_time_ms),
1.700 + "min_young_length, the result of the binary search, should "
1.701 + "fit into the pause target");
1.702 + assert(!predict_will_fit(min_young_length + 1, base_time_ms,
1.703 + base_free_regions, target_pause_time_ms),
1.704 + "min_young_length, the result of the binary search, should be "
1.705 + "optimal, so no larger length should fit into the pause target");
1.706 + }
1.707 + } else {
1.708 + // Even the minimum length doesn't fit into the pause time
1.709 + // target, return it as the result nevertheless.
1.710 + }
1.711 + return base_min_length + min_young_length;
1.712 +}
1.713 +
1.714 +double G1CollectorPolicy::predict_survivor_regions_evac_time() {
1.715 + double survivor_regions_evac_time = 0.0;
1.716 + for (HeapRegion * r = _recorded_survivor_head;
1.717 + r != NULL && r != _recorded_survivor_tail->get_next_young_region();
1.718 + r = r->get_next_young_region()) {
1.719 + survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young());
1.720 + }
1.721 + return survivor_regions_evac_time;
1.722 +}
1.723 +
1.724 +void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
1.725 + guarantee( adaptive_young_list_length(), "should not call this otherwise" );
1.726 +
1.727 + size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
1.728 + if (rs_lengths > _rs_lengths_prediction) {
1.729 + // add 10% to avoid having to recalculate often
1.730 + size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
1.731 + update_young_list_target_length(rs_lengths_prediction);
1.732 + }
1.733 +}
1.734 +
1.735 +
1.736 +
1.737 +HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
1.738 + bool is_tlab,
1.739 + bool* gc_overhead_limit_was_exceeded) {
1.740 + guarantee(false, "Not using this policy feature yet.");
1.741 + return NULL;
1.742 +}
1.743 +
1.744 +// This method controls how a collector handles one or more
1.745 +// of its generations being fully allocated.
1.746 +HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
1.747 + bool is_tlab) {
1.748 + guarantee(false, "Not using this policy feature yet.");
1.749 + return NULL;
1.750 +}
1.751 +
1.752 +
1.753 +#ifndef PRODUCT
1.754 +bool G1CollectorPolicy::verify_young_ages() {
1.755 + HeapRegion* head = _g1->young_list()->first_region();
1.756 + return
1.757 + verify_young_ages(head, _short_lived_surv_rate_group);
1.758 + // also call verify_young_ages on any additional surv rate groups
1.759 +}
1.760 +
1.761 +bool
1.762 +G1CollectorPolicy::verify_young_ages(HeapRegion* head,
1.763 + SurvRateGroup *surv_rate_group) {
1.764 + guarantee( surv_rate_group != NULL, "pre-condition" );
1.765 +
1.766 + const char* name = surv_rate_group->name();
1.767 + bool ret = true;
1.768 + int prev_age = -1;
1.769 +
1.770 + for (HeapRegion* curr = head;
1.771 + curr != NULL;
1.772 + curr = curr->get_next_young_region()) {
1.773 + SurvRateGroup* group = curr->surv_rate_group();
1.774 + if (group == NULL && !curr->is_survivor()) {
1.775 + gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
1.776 + ret = false;
1.777 + }
1.778 +
1.779 + if (surv_rate_group == group) {
1.780 + int age = curr->age_in_surv_rate_group();
1.781 +
1.782 + if (age < 0) {
1.783 + gclog_or_tty->print_cr("## %s: encountered negative age", name);
1.784 + ret = false;
1.785 + }
1.786 +
1.787 + if (age <= prev_age) {
1.788 + gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
1.789 + "(%d, %d)", name, age, prev_age);
1.790 + ret = false;
1.791 + }
1.792 + prev_age = age;
1.793 + }
1.794 + }
1.795 +
1.796 + return ret;
1.797 +}
1.798 +#endif // PRODUCT
1.799 +
1.800 +void G1CollectorPolicy::record_full_collection_start() {
1.801 + _full_collection_start_sec = os::elapsedTime();
1.802 + record_heap_size_info_at_start(true /* full */);
1.803 + // Release the future to-space so that it is available for compaction into.
1.804 + _g1->set_full_collection();
1.805 +}
1.806 +
1.807 +void G1CollectorPolicy::record_full_collection_end() {
1.808 + // Consider this like a collection pause for the purposes of allocation
1.809 + // since last pause.
1.810 + double end_sec = os::elapsedTime();
1.811 + double full_gc_time_sec = end_sec - _full_collection_start_sec;
1.812 + double full_gc_time_ms = full_gc_time_sec * 1000.0;
1.813 +
1.814 + _trace_gen1_time_data.record_full_collection(full_gc_time_ms);
1.815 +
1.816 + update_recent_gc_times(end_sec, full_gc_time_ms);
1.817 +
1.818 + _g1->clear_full_collection();
1.819 +
1.820 + // "Nuke" the heuristics that control the young/mixed GC
1.821 + // transitions and make sure we start with young GCs after the Full GC.
1.822 + set_gcs_are_young(true);
1.823 + _last_young_gc = false;
1.824 + clear_initiate_conc_mark_if_possible();
1.825 + clear_during_initial_mark_pause();
1.826 + _in_marking_window = false;
1.827 + _in_marking_window_im = false;
1.828 +
1.829 + _short_lived_surv_rate_group->start_adding_regions();
1.830 + // also call this on any additional surv rate groups
1.831 +
1.832 + record_survivor_regions(0, NULL, NULL);
1.833 +
1.834 + _free_regions_at_end_of_collection = _g1->free_regions();
1.835 + // Reset survivors SurvRateGroup.
1.836 + _survivor_surv_rate_group->reset();
1.837 + update_young_list_target_length();
1.838 + _collectionSetChooser->clear();
1.839 +}
1.840 +
1.841 +void G1CollectorPolicy::record_stop_world_start() {
1.842 + _stop_world_start = os::elapsedTime();
1.843 +}
1.844 +
1.845 +void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
1.846 + // We only need to do this here as the policy will only be applied
1.847 + // to the GC we're about to start. so, no point is calculating this
1.848 + // every time we calculate / recalculate the target young length.
1.849 + update_survivors_policy();
1.850 +
1.851 + assert(_g1->used() == _g1->recalculate_used(),
1.852 + err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
1.853 + _g1->used(), _g1->recalculate_used()));
1.854 +
1.855 + double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
1.856 + _trace_gen0_time_data.record_start_collection(s_w_t_ms);
1.857 + _stop_world_start = 0.0;
1.858 +
1.859 + record_heap_size_info_at_start(false /* full */);
1.860 +
1.861 + phase_times()->record_cur_collection_start_sec(start_time_sec);
1.862 + _pending_cards = _g1->pending_card_num();
1.863 +
1.864 + _collection_set_bytes_used_before = 0;
1.865 + _bytes_copied_during_gc = 0;
1.866 +
1.867 + _last_gc_was_young = false;
1.868 +
1.869 + // do that for any other surv rate groups
1.870 + _short_lived_surv_rate_group->stop_adding_regions();
1.871 + _survivors_age_table.clear();
1.872 +
1.873 + assert( verify_young_ages(), "region age verification" );
1.874 +}
1.875 +
1.876 +void G1CollectorPolicy::record_concurrent_mark_init_end(double
1.877 + mark_init_elapsed_time_ms) {
1.878 + _during_marking = true;
1.879 + assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
1.880 + clear_during_initial_mark_pause();
1.881 + _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
1.882 +}
1.883 +
1.884 +void G1CollectorPolicy::record_concurrent_mark_remark_start() {
1.885 + _mark_remark_start_sec = os::elapsedTime();
1.886 + _during_marking = false;
1.887 +}
1.888 +
1.889 +void G1CollectorPolicy::record_concurrent_mark_remark_end() {
1.890 + double end_time_sec = os::elapsedTime();
1.891 + double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
1.892 + _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
1.893 + _cur_mark_stop_world_time_ms += elapsed_time_ms;
1.894 + _prev_collection_pause_end_ms += elapsed_time_ms;
1.895 +
1.896 + _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
1.897 +}
1.898 +
1.899 +void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
1.900 + _mark_cleanup_start_sec = os::elapsedTime();
1.901 +}
1.902 +
1.903 +void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
1.904 + _last_young_gc = true;
1.905 + _in_marking_window = false;
1.906 +}
1.907 +
1.908 +void G1CollectorPolicy::record_concurrent_pause() {
1.909 + if (_stop_world_start > 0.0) {
1.910 + double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
1.911 + _trace_gen0_time_data.record_yield_time(yield_ms);
1.912 + }
1.913 +}
1.914 +
1.915 +bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
1.916 + if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
1.917 + return false;
1.918 + }
1.919 +
1.920 + size_t marking_initiating_used_threshold =
1.921 + (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
1.922 + size_t cur_used_bytes = _g1->non_young_capacity_bytes();
1.923 + size_t alloc_byte_size = alloc_word_size * HeapWordSize;
1.924 +
1.925 + if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
1.926 + if (gcs_are_young() && !_last_young_gc) {
1.927 + ergo_verbose5(ErgoConcCycles,
1.928 + "request concurrent cycle initiation",
1.929 + ergo_format_reason("occupancy higher than threshold")
1.930 + ergo_format_byte("occupancy")
1.931 + ergo_format_byte("allocation request")
1.932 + ergo_format_byte_perc("threshold")
1.933 + ergo_format_str("source"),
1.934 + cur_used_bytes,
1.935 + alloc_byte_size,
1.936 + marking_initiating_used_threshold,
1.937 + (double) InitiatingHeapOccupancyPercent,
1.938 + source);
1.939 + return true;
1.940 + } else {
1.941 + ergo_verbose5(ErgoConcCycles,
1.942 + "do not request concurrent cycle initiation",
1.943 + ergo_format_reason("still doing mixed collections")
1.944 + ergo_format_byte("occupancy")
1.945 + ergo_format_byte("allocation request")
1.946 + ergo_format_byte_perc("threshold")
1.947 + ergo_format_str("source"),
1.948 + cur_used_bytes,
1.949 + alloc_byte_size,
1.950 + marking_initiating_used_threshold,
1.951 + (double) InitiatingHeapOccupancyPercent,
1.952 + source);
1.953 + }
1.954 + }
1.955 +
1.956 + return false;
1.957 +}
1.958 +
1.959 +// Anything below that is considered to be zero
1.960 +#define MIN_TIMER_GRANULARITY 0.0000001
1.961 +
1.962 +void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info) {
1.963 + double end_time_sec = os::elapsedTime();
1.964 + assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
1.965 + "otherwise, the subtraction below does not make sense");
1.966 + size_t rs_size =
1.967 + _cur_collection_pause_used_regions_at_start - cset_region_length();
1.968 + size_t cur_used_bytes = _g1->used();
1.969 + assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1.970 + bool last_pause_included_initial_mark = false;
1.971 + bool update_stats = !_g1->evacuation_failed();
1.972 +
1.973 +#ifndef PRODUCT
1.974 + if (G1YoungSurvRateVerbose) {
1.975 + gclog_or_tty->cr();
1.976 + _short_lived_surv_rate_group->print();
1.977 + // do that for any other surv rate groups too
1.978 + }
1.979 +#endif // PRODUCT
1.980 +
1.981 + last_pause_included_initial_mark = during_initial_mark_pause();
1.982 + if (last_pause_included_initial_mark) {
1.983 + record_concurrent_mark_init_end(0.0);
1.984 + } else if (need_to_start_conc_mark("end of GC")) {
1.985 + // Note: this might have already been set, if during the last
1.986 + // pause we decided to start a cycle but at the beginning of
1.987 + // this pause we decided to postpone it. That's OK.
1.988 + set_initiate_conc_mark_if_possible();
1.989 + }
1.990 +
1.991 + _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0,
1.992 + end_time_sec, false);
1.993 +
1.994 + evacuation_info.set_collectionset_used_before(_collection_set_bytes_used_before);
1.995 + evacuation_info.set_bytes_copied(_bytes_copied_during_gc);
1.996 +
1.997 + if (update_stats) {
1.998 + _trace_gen0_time_data.record_end_collection(pause_time_ms, phase_times());
1.999 + // this is where we update the allocation rate of the application
1.1000 + double app_time_ms =
1.1001 + (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
1.1002 + if (app_time_ms < MIN_TIMER_GRANULARITY) {
1.1003 + // This usually happens due to the timer not having the required
1.1004 + // granularity. Some Linuxes are the usual culprits.
1.1005 + // We'll just set it to something (arbitrarily) small.
1.1006 + app_time_ms = 1.0;
1.1007 + }
1.1008 + // We maintain the invariant that all objects allocated by mutator
1.1009 + // threads will be allocated out of eden regions. So, we can use
1.1010 + // the eden region number allocated since the previous GC to
1.1011 + // calculate the application's allocate rate. The only exception
1.1012 + // to that is humongous objects that are allocated separately. But
1.1013 + // given that humongous object allocations do not really affect
1.1014 + // either the pause's duration nor when the next pause will take
1.1015 + // place we can safely ignore them here.
1.1016 + uint regions_allocated = eden_cset_region_length();
1.1017 + double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1.1018 + _alloc_rate_ms_seq->add(alloc_rate_ms);
1.1019 +
1.1020 + double interval_ms =
1.1021 + (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1.1022 + update_recent_gc_times(end_time_sec, pause_time_ms);
1.1023 + _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1.1024 + if (recent_avg_pause_time_ratio() < 0.0 ||
1.1025 + (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1.1026 +#ifndef PRODUCT
1.1027 + // Dump info to allow post-facto debugging
1.1028 + gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1.1029 + gclog_or_tty->print_cr("-------------------------------------------");
1.1030 + gclog_or_tty->print_cr("Recent GC Times (ms):");
1.1031 + _recent_gc_times_ms->dump();
1.1032 + gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1.1033 + _recent_prev_end_times_for_all_gcs_sec->dump();
1.1034 + gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1.1035 + _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1.1036 + // In debug mode, terminate the JVM if the user wants to debug at this point.
1.1037 + assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1.1038 +#endif // !PRODUCT
1.1039 + // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1.1040 + // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1.1041 + if (_recent_avg_pause_time_ratio < 0.0) {
1.1042 + _recent_avg_pause_time_ratio = 0.0;
1.1043 + } else {
1.1044 + assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1.1045 + _recent_avg_pause_time_ratio = 1.0;
1.1046 + }
1.1047 + }
1.1048 + }
1.1049 +
1.1050 + bool new_in_marking_window = _in_marking_window;
1.1051 + bool new_in_marking_window_im = false;
1.1052 + if (during_initial_mark_pause()) {
1.1053 + new_in_marking_window = true;
1.1054 + new_in_marking_window_im = true;
1.1055 + }
1.1056 +
1.1057 + if (_last_young_gc) {
1.1058 + // This is supposed to to be the "last young GC" before we start
1.1059 + // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1.1060 +
1.1061 + if (!last_pause_included_initial_mark) {
1.1062 + if (next_gc_should_be_mixed("start mixed GCs",
1.1063 + "do not start mixed GCs")) {
1.1064 + set_gcs_are_young(false);
1.1065 + }
1.1066 + } else {
1.1067 + ergo_verbose0(ErgoMixedGCs,
1.1068 + "do not start mixed GCs",
1.1069 + ergo_format_reason("concurrent cycle is about to start"));
1.1070 + }
1.1071 + _last_young_gc = false;
1.1072 + }
1.1073 +
1.1074 + if (!_last_gc_was_young) {
1.1075 + // This is a mixed GC. Here we decide whether to continue doing
1.1076 + // mixed GCs or not.
1.1077 +
1.1078 + if (!next_gc_should_be_mixed("continue mixed GCs",
1.1079 + "do not continue mixed GCs")) {
1.1080 + set_gcs_are_young(true);
1.1081 + }
1.1082 + }
1.1083 +
1.1084 + _short_lived_surv_rate_group->start_adding_regions();
1.1085 + // do that for any other surv rate groupsx
1.1086 +
1.1087 + if (update_stats) {
1.1088 + double cost_per_card_ms = 0.0;
1.1089 + if (_pending_cards > 0) {
1.1090 + cost_per_card_ms = phase_times()->average_last_update_rs_time() / (double) _pending_cards;
1.1091 + _cost_per_card_ms_seq->add(cost_per_card_ms);
1.1092 + }
1.1093 +
1.1094 + size_t cards_scanned = _g1->cards_scanned();
1.1095 +
1.1096 + double cost_per_entry_ms = 0.0;
1.1097 + if (cards_scanned > 10) {
1.1098 + cost_per_entry_ms = phase_times()->average_last_scan_rs_time() / (double) cards_scanned;
1.1099 + if (_last_gc_was_young) {
1.1100 + _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1.1101 + } else {
1.1102 + _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1.1103 + }
1.1104 + }
1.1105 +
1.1106 + if (_max_rs_lengths > 0) {
1.1107 + double cards_per_entry_ratio =
1.1108 + (double) cards_scanned / (double) _max_rs_lengths;
1.1109 + if (_last_gc_was_young) {
1.1110 + _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1.1111 + } else {
1.1112 + _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1.1113 + }
1.1114 + }
1.1115 +
1.1116 + // This is defensive. For a while _max_rs_lengths could get
1.1117 + // smaller than _recorded_rs_lengths which was causing
1.1118 + // rs_length_diff to get very large and mess up the RSet length
1.1119 + // predictions. The reason was unsafe concurrent updates to the
1.1120 + // _inc_cset_recorded_rs_lengths field which the code below guards
1.1121 + // against (see CR 7118202). This bug has now been fixed (see CR
1.1122 + // 7119027). However, I'm still worried that
1.1123 + // _inc_cset_recorded_rs_lengths might still end up somewhat
1.1124 + // inaccurate. The concurrent refinement thread calculates an
1.1125 + // RSet's length concurrently with other CR threads updating it
1.1126 + // which might cause it to calculate the length incorrectly (if,
1.1127 + // say, it's in mid-coarsening). So I'll leave in the defensive
1.1128 + // conditional below just in case.
1.1129 + size_t rs_length_diff = 0;
1.1130 + if (_max_rs_lengths > _recorded_rs_lengths) {
1.1131 + rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1.1132 + }
1.1133 + _rs_length_diff_seq->add((double) rs_length_diff);
1.1134 +
1.1135 + size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1.1136 + size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1.1137 + double cost_per_byte_ms = 0.0;
1.1138 +
1.1139 + if (copied_bytes > 0) {
1.1140 + cost_per_byte_ms = phase_times()->average_last_obj_copy_time() / (double) copied_bytes;
1.1141 + if (_in_marking_window) {
1.1142 + _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1.1143 + } else {
1.1144 + _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1.1145 + }
1.1146 + }
1.1147 +
1.1148 + double all_other_time_ms = pause_time_ms -
1.1149 + (phase_times()->average_last_update_rs_time() + phase_times()->average_last_scan_rs_time()
1.1150 + + phase_times()->average_last_obj_copy_time() + phase_times()->average_last_termination_time());
1.1151 +
1.1152 + double young_other_time_ms = 0.0;
1.1153 + if (young_cset_region_length() > 0) {
1.1154 + young_other_time_ms =
1.1155 + phase_times()->young_cset_choice_time_ms() +
1.1156 + phase_times()->young_free_cset_time_ms();
1.1157 + _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1.1158 + (double) young_cset_region_length());
1.1159 + }
1.1160 + double non_young_other_time_ms = 0.0;
1.1161 + if (old_cset_region_length() > 0) {
1.1162 + non_young_other_time_ms =
1.1163 + phase_times()->non_young_cset_choice_time_ms() +
1.1164 + phase_times()->non_young_free_cset_time_ms();
1.1165 +
1.1166 + _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1.1167 + (double) old_cset_region_length());
1.1168 + }
1.1169 +
1.1170 + double constant_other_time_ms = all_other_time_ms -
1.1171 + (young_other_time_ms + non_young_other_time_ms);
1.1172 + _constant_other_time_ms_seq->add(constant_other_time_ms);
1.1173 +
1.1174 + double survival_ratio = 0.0;
1.1175 + if (_collection_set_bytes_used_before > 0) {
1.1176 + survival_ratio = (double) _bytes_copied_during_gc /
1.1177 + (double) _collection_set_bytes_used_before;
1.1178 + }
1.1179 +
1.1180 + _pending_cards_seq->add((double) _pending_cards);
1.1181 + _rs_lengths_seq->add((double) _max_rs_lengths);
1.1182 + }
1.1183 +
1.1184 + _in_marking_window = new_in_marking_window;
1.1185 + _in_marking_window_im = new_in_marking_window_im;
1.1186 + _free_regions_at_end_of_collection = _g1->free_regions();
1.1187 + update_young_list_target_length();
1.1188 +
1.1189 + // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1.1190 + double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1.1191 + adjust_concurrent_refinement(phase_times()->average_last_update_rs_time(),
1.1192 + phase_times()->sum_last_update_rs_processed_buffers(), update_rs_time_goal_ms);
1.1193 +
1.1194 + _collectionSetChooser->verify();
1.1195 +}
1.1196 +
1.1197 +#define EXT_SIZE_FORMAT "%.1f%s"
1.1198 +#define EXT_SIZE_PARAMS(bytes) \
1.1199 + byte_size_in_proper_unit((double)(bytes)), \
1.1200 + proper_unit_for_byte_size((bytes))
1.1201 +
1.1202 +void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1.1203 + YoungList* young_list = _g1->young_list();
1.1204 + _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1.1205 + _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1.1206 + _heap_capacity_bytes_before_gc = _g1->capacity();
1.1207 + _heap_used_bytes_before_gc = _g1->used();
1.1208 + _cur_collection_pause_used_regions_at_start = _g1->used_regions();
1.1209 +
1.1210 + _eden_capacity_bytes_before_gc =
1.1211 + (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1.1212 +
1.1213 + if (full) {
1.1214 + _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1.1215 + }
1.1216 +}
1.1217 +
1.1218 +void G1CollectorPolicy::print_heap_transition() {
1.1219 + _g1->print_size_transition(gclog_or_tty,
1.1220 + _heap_used_bytes_before_gc,
1.1221 + _g1->used(),
1.1222 + _g1->capacity());
1.1223 +}
1.1224 +
1.1225 +void G1CollectorPolicy::print_detailed_heap_transition(bool full) {
1.1226 + YoungList* young_list = _g1->young_list();
1.1227 +
1.1228 + size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1.1229 + size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1.1230 + size_t heap_used_bytes_after_gc = _g1->used();
1.1231 +
1.1232 + size_t heap_capacity_bytes_after_gc = _g1->capacity();
1.1233 + size_t eden_capacity_bytes_after_gc =
1.1234 + (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1.1235 +
1.1236 + gclog_or_tty->print(
1.1237 + " [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
1.1238 + "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1.1239 + "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
1.1240 + EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
1.1241 + EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1.1242 + EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1.1243 + EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1.1244 + EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1.1245 + EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1.1246 + EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1.1247 + EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1.1248 + EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1.1249 + EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1.1250 + EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1.1251 +
1.1252 + if (full) {
1.1253 + MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1.1254 + }
1.1255 +
1.1256 + gclog_or_tty->cr();
1.1257 +}
1.1258 +
1.1259 +void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1.1260 + double update_rs_processed_buffers,
1.1261 + double goal_ms) {
1.1262 + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1.1263 + ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1.1264 +
1.1265 + if (G1UseAdaptiveConcRefinement) {
1.1266 + const int k_gy = 3, k_gr = 6;
1.1267 + const double inc_k = 1.1, dec_k = 0.9;
1.1268 +
1.1269 + int g = cg1r->green_zone();
1.1270 + if (update_rs_time > goal_ms) {
1.1271 + g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1.1272 + } else {
1.1273 + if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1.1274 + g = (int)MAX2(g * inc_k, g + 1.0);
1.1275 + }
1.1276 + }
1.1277 + // Change the refinement threads params
1.1278 + cg1r->set_green_zone(g);
1.1279 + cg1r->set_yellow_zone(g * k_gy);
1.1280 + cg1r->set_red_zone(g * k_gr);
1.1281 + cg1r->reinitialize_threads();
1.1282 +
1.1283 + int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1.1284 + int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1.1285 + cg1r->yellow_zone());
1.1286 + // Change the barrier params
1.1287 + dcqs.set_process_completed_threshold(processing_threshold);
1.1288 + dcqs.set_max_completed_queue(cg1r->red_zone());
1.1289 + }
1.1290 +
1.1291 + int curr_queue_size = dcqs.completed_buffers_num();
1.1292 + if (curr_queue_size >= cg1r->yellow_zone()) {
1.1293 + dcqs.set_completed_queue_padding(curr_queue_size);
1.1294 + } else {
1.1295 + dcqs.set_completed_queue_padding(0);
1.1296 + }
1.1297 + dcqs.notify_if_necessary();
1.1298 +}
1.1299 +
1.1300 +double
1.1301 +G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1.1302 + size_t scanned_cards) {
1.1303 + return
1.1304 + predict_rs_update_time_ms(pending_cards) +
1.1305 + predict_rs_scan_time_ms(scanned_cards) +
1.1306 + predict_constant_other_time_ms();
1.1307 +}
1.1308 +
1.1309 +double
1.1310 +G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1.1311 + size_t rs_length = predict_rs_length_diff();
1.1312 + size_t card_num;
1.1313 + if (gcs_are_young()) {
1.1314 + card_num = predict_young_card_num(rs_length);
1.1315 + } else {
1.1316 + card_num = predict_non_young_card_num(rs_length);
1.1317 + }
1.1318 + return predict_base_elapsed_time_ms(pending_cards, card_num);
1.1319 +}
1.1320 +
1.1321 +size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1.1322 + size_t bytes_to_copy;
1.1323 + if (hr->is_marked())
1.1324 + bytes_to_copy = hr->max_live_bytes();
1.1325 + else {
1.1326 + assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1.1327 + int age = hr->age_in_surv_rate_group();
1.1328 + double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1.1329 + bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1.1330 + }
1.1331 + return bytes_to_copy;
1.1332 +}
1.1333 +
1.1334 +double
1.1335 +G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1.1336 + bool for_young_gc) {
1.1337 + size_t rs_length = hr->rem_set()->occupied();
1.1338 + size_t card_num;
1.1339 +
1.1340 + // Predicting the number of cards is based on which type of GC
1.1341 + // we're predicting for.
1.1342 + if (for_young_gc) {
1.1343 + card_num = predict_young_card_num(rs_length);
1.1344 + } else {
1.1345 + card_num = predict_non_young_card_num(rs_length);
1.1346 + }
1.1347 + size_t bytes_to_copy = predict_bytes_to_copy(hr);
1.1348 +
1.1349 + double region_elapsed_time_ms =
1.1350 + predict_rs_scan_time_ms(card_num) +
1.1351 + predict_object_copy_time_ms(bytes_to_copy);
1.1352 +
1.1353 + // The prediction of the "other" time for this region is based
1.1354 + // upon the region type and NOT the GC type.
1.1355 + if (hr->is_young()) {
1.1356 + region_elapsed_time_ms += predict_young_other_time_ms(1);
1.1357 + } else {
1.1358 + region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1.1359 + }
1.1360 + return region_elapsed_time_ms;
1.1361 +}
1.1362 +
1.1363 +void
1.1364 +G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1.1365 + uint survivor_cset_region_length) {
1.1366 + _eden_cset_region_length = eden_cset_region_length;
1.1367 + _survivor_cset_region_length = survivor_cset_region_length;
1.1368 + _old_cset_region_length = 0;
1.1369 +}
1.1370 +
1.1371 +void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1.1372 + _recorded_rs_lengths = rs_lengths;
1.1373 +}
1.1374 +
1.1375 +void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1.1376 + double elapsed_ms) {
1.1377 + _recent_gc_times_ms->add(elapsed_ms);
1.1378 + _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1.1379 + _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1.1380 +}
1.1381 +
1.1382 +size_t G1CollectorPolicy::expansion_amount() {
1.1383 + double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1.1384 + double threshold = _gc_overhead_perc;
1.1385 + if (recent_gc_overhead > threshold) {
1.1386 + // We will double the existing space, or take
1.1387 + // G1ExpandByPercentOfAvailable % of the available expansion
1.1388 + // space, whichever is smaller, bounded below by a minimum
1.1389 + // expansion (unless that's all that's left.)
1.1390 + const size_t min_expand_bytes = 1*M;
1.1391 + size_t reserved_bytes = _g1->max_capacity();
1.1392 + size_t committed_bytes = _g1->capacity();
1.1393 + size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1.1394 + size_t expand_bytes;
1.1395 + size_t expand_bytes_via_pct =
1.1396 + uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1.1397 + expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1.1398 + expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1.1399 + expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1.1400 +
1.1401 + ergo_verbose5(ErgoHeapSizing,
1.1402 + "attempt heap expansion",
1.1403 + ergo_format_reason("recent GC overhead higher than "
1.1404 + "threshold after GC")
1.1405 + ergo_format_perc("recent GC overhead")
1.1406 + ergo_format_perc("threshold")
1.1407 + ergo_format_byte("uncommitted")
1.1408 + ergo_format_byte_perc("calculated expansion amount"),
1.1409 + recent_gc_overhead, threshold,
1.1410 + uncommitted_bytes,
1.1411 + expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1.1412 +
1.1413 + return expand_bytes;
1.1414 + } else {
1.1415 + return 0;
1.1416 + }
1.1417 +}
1.1418 +
1.1419 +void G1CollectorPolicy::print_tracing_info() const {
1.1420 + _trace_gen0_time_data.print();
1.1421 + _trace_gen1_time_data.print();
1.1422 +}
1.1423 +
1.1424 +void G1CollectorPolicy::print_yg_surv_rate_info() const {
1.1425 +#ifndef PRODUCT
1.1426 + _short_lived_surv_rate_group->print_surv_rate_summary();
1.1427 + // add this call for any other surv rate groups
1.1428 +#endif // PRODUCT
1.1429 +}
1.1430 +
1.1431 +uint G1CollectorPolicy::max_regions(int purpose) {
1.1432 + switch (purpose) {
1.1433 + case GCAllocForSurvived:
1.1434 + return _max_survivor_regions;
1.1435 + case GCAllocForTenured:
1.1436 + return REGIONS_UNLIMITED;
1.1437 + default:
1.1438 + ShouldNotReachHere();
1.1439 + return REGIONS_UNLIMITED;
1.1440 + };
1.1441 +}
1.1442 +
1.1443 +void G1CollectorPolicy::update_max_gc_locker_expansion() {
1.1444 + uint expansion_region_num = 0;
1.1445 + if (GCLockerEdenExpansionPercent > 0) {
1.1446 + double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1.1447 + double expansion_region_num_d = perc * (double) _young_list_target_length;
1.1448 + // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1.1449 + // less than 1.0) we'll get 1.
1.1450 + expansion_region_num = (uint) ceil(expansion_region_num_d);
1.1451 + } else {
1.1452 + assert(expansion_region_num == 0, "sanity");
1.1453 + }
1.1454 + _young_list_max_length = _young_list_target_length + expansion_region_num;
1.1455 + assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1.1456 +}
1.1457 +
1.1458 +// Calculates survivor space parameters.
1.1459 +void G1CollectorPolicy::update_survivors_policy() {
1.1460 + double max_survivor_regions_d =
1.1461 + (double) _young_list_target_length / (double) SurvivorRatio;
1.1462 + // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1.1463 + // smaller than 1.0) we'll get 1.
1.1464 + _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1.1465 +
1.1466 + _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1.1467 + HeapRegion::GrainWords * _max_survivor_regions);
1.1468 +}
1.1469 +
1.1470 +bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
1.1471 + GCCause::Cause gc_cause) {
1.1472 + bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1.1473 + if (!during_cycle) {
1.1474 + ergo_verbose1(ErgoConcCycles,
1.1475 + "request concurrent cycle initiation",
1.1476 + ergo_format_reason("requested by GC cause")
1.1477 + ergo_format_str("GC cause"),
1.1478 + GCCause::to_string(gc_cause));
1.1479 + set_initiate_conc_mark_if_possible();
1.1480 + return true;
1.1481 + } else {
1.1482 + ergo_verbose1(ErgoConcCycles,
1.1483 + "do not request concurrent cycle initiation",
1.1484 + ergo_format_reason("concurrent cycle already in progress")
1.1485 + ergo_format_str("GC cause"),
1.1486 + GCCause::to_string(gc_cause));
1.1487 + return false;
1.1488 + }
1.1489 +}
1.1490 +
1.1491 +void
1.1492 +G1CollectorPolicy::decide_on_conc_mark_initiation() {
1.1493 + // We are about to decide on whether this pause will be an
1.1494 + // initial-mark pause.
1.1495 +
1.1496 + // First, during_initial_mark_pause() should not be already set. We
1.1497 + // will set it here if we have to. However, it should be cleared by
1.1498 + // the end of the pause (it's only set for the duration of an
1.1499 + // initial-mark pause).
1.1500 + assert(!during_initial_mark_pause(), "pre-condition");
1.1501 +
1.1502 + if (initiate_conc_mark_if_possible()) {
1.1503 + // We had noticed on a previous pause that the heap occupancy has
1.1504 + // gone over the initiating threshold and we should start a
1.1505 + // concurrent marking cycle. So we might initiate one.
1.1506 +
1.1507 + bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1.1508 + if (!during_cycle) {
1.1509 + // The concurrent marking thread is not "during a cycle", i.e.,
1.1510 + // it has completed the last one. So we can go ahead and
1.1511 + // initiate a new cycle.
1.1512 +
1.1513 + set_during_initial_mark_pause();
1.1514 + // We do not allow mixed GCs during marking.
1.1515 + if (!gcs_are_young()) {
1.1516 + set_gcs_are_young(true);
1.1517 + ergo_verbose0(ErgoMixedGCs,
1.1518 + "end mixed GCs",
1.1519 + ergo_format_reason("concurrent cycle is about to start"));
1.1520 + }
1.1521 +
1.1522 + // And we can now clear initiate_conc_mark_if_possible() as
1.1523 + // we've already acted on it.
1.1524 + clear_initiate_conc_mark_if_possible();
1.1525 +
1.1526 + ergo_verbose0(ErgoConcCycles,
1.1527 + "initiate concurrent cycle",
1.1528 + ergo_format_reason("concurrent cycle initiation requested"));
1.1529 + } else {
1.1530 + // The concurrent marking thread is still finishing up the
1.1531 + // previous cycle. If we start one right now the two cycles
1.1532 + // overlap. In particular, the concurrent marking thread might
1.1533 + // be in the process of clearing the next marking bitmap (which
1.1534 + // we will use for the next cycle if we start one). Starting a
1.1535 + // cycle now will be bad given that parts of the marking
1.1536 + // information might get cleared by the marking thread. And we
1.1537 + // cannot wait for the marking thread to finish the cycle as it
1.1538 + // periodically yields while clearing the next marking bitmap
1.1539 + // and, if it's in a yield point, it's waiting for us to
1.1540 + // finish. So, at this point we will not start a cycle and we'll
1.1541 + // let the concurrent marking thread complete the last one.
1.1542 + ergo_verbose0(ErgoConcCycles,
1.1543 + "do not initiate concurrent cycle",
1.1544 + ergo_format_reason("concurrent cycle already in progress"));
1.1545 + }
1.1546 + }
1.1547 +}
1.1548 +
1.1549 +class KnownGarbageClosure: public HeapRegionClosure {
1.1550 + G1CollectedHeap* _g1h;
1.1551 + CollectionSetChooser* _hrSorted;
1.1552 +
1.1553 +public:
1.1554 + KnownGarbageClosure(CollectionSetChooser* hrSorted) :
1.1555 + _g1h(G1CollectedHeap::heap()), _hrSorted(hrSorted) { }
1.1556 +
1.1557 + bool doHeapRegion(HeapRegion* r) {
1.1558 + // We only include humongous regions in collection
1.1559 + // sets when concurrent mark shows that their contained object is
1.1560 + // unreachable.
1.1561 +
1.1562 + // Do we have any marking information for this region?
1.1563 + if (r->is_marked()) {
1.1564 + // We will skip any region that's currently used as an old GC
1.1565 + // alloc region (we should not consider those for collection
1.1566 + // before we fill them up).
1.1567 + if (_hrSorted->should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1.1568 + _hrSorted->add_region(r);
1.1569 + }
1.1570 + }
1.1571 + return false;
1.1572 + }
1.1573 +};
1.1574 +
1.1575 +class ParKnownGarbageHRClosure: public HeapRegionClosure {
1.1576 + G1CollectedHeap* _g1h;
1.1577 + CSetChooserParUpdater _cset_updater;
1.1578 +
1.1579 +public:
1.1580 + ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1.1581 + uint chunk_size) :
1.1582 + _g1h(G1CollectedHeap::heap()),
1.1583 + _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1.1584 +
1.1585 + bool doHeapRegion(HeapRegion* r) {
1.1586 + // Do we have any marking information for this region?
1.1587 + if (r->is_marked()) {
1.1588 + // We will skip any region that's currently used as an old GC
1.1589 + // alloc region (we should not consider those for collection
1.1590 + // before we fill them up).
1.1591 + if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1.1592 + _cset_updater.add_region(r);
1.1593 + }
1.1594 + }
1.1595 + return false;
1.1596 + }
1.1597 +};
1.1598 +
1.1599 +class ParKnownGarbageTask: public AbstractGangTask {
1.1600 + CollectionSetChooser* _hrSorted;
1.1601 + uint _chunk_size;
1.1602 + G1CollectedHeap* _g1;
1.1603 +public:
1.1604 + ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size) :
1.1605 + AbstractGangTask("ParKnownGarbageTask"),
1.1606 + _hrSorted(hrSorted), _chunk_size(chunk_size),
1.1607 + _g1(G1CollectedHeap::heap()) { }
1.1608 +
1.1609 + void work(uint worker_id) {
1.1610 + ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1.1611 +
1.1612 + // Back to zero for the claim value.
1.1613 + _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, worker_id,
1.1614 + _g1->workers()->active_workers(),
1.1615 + HeapRegion::InitialClaimValue);
1.1616 + }
1.1617 +};
1.1618 +
1.1619 +void
1.1620 +G1CollectorPolicy::record_concurrent_mark_cleanup_end(int no_of_gc_threads) {
1.1621 + _collectionSetChooser->clear();
1.1622 +
1.1623 + uint region_num = _g1->n_regions();
1.1624 + if (G1CollectedHeap::use_parallel_gc_threads()) {
1.1625 + const uint OverpartitionFactor = 4;
1.1626 + uint WorkUnit;
1.1627 + // The use of MinChunkSize = 8 in the original code
1.1628 + // causes some assertion failures when the total number of
1.1629 + // region is less than 8. The code here tries to fix that.
1.1630 + // Should the original code also be fixed?
1.1631 + if (no_of_gc_threads > 0) {
1.1632 + const uint MinWorkUnit = MAX2(region_num / no_of_gc_threads, 1U);
1.1633 + WorkUnit = MAX2(region_num / (no_of_gc_threads * OverpartitionFactor),
1.1634 + MinWorkUnit);
1.1635 + } else {
1.1636 + assert(no_of_gc_threads > 0,
1.1637 + "The active gc workers should be greater than 0");
1.1638 + // In a product build do something reasonable to avoid a crash.
1.1639 + const uint MinWorkUnit = MAX2(region_num / (uint) ParallelGCThreads, 1U);
1.1640 + WorkUnit =
1.1641 + MAX2(region_num / (uint) (ParallelGCThreads * OverpartitionFactor),
1.1642 + MinWorkUnit);
1.1643 + }
1.1644 + _collectionSetChooser->prepare_for_par_region_addition(_g1->n_regions(),
1.1645 + WorkUnit);
1.1646 + ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
1.1647 + (int) WorkUnit);
1.1648 + _g1->workers()->run_task(&parKnownGarbageTask);
1.1649 +
1.1650 + assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
1.1651 + "sanity check");
1.1652 + } else {
1.1653 + KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
1.1654 + _g1->heap_region_iterate(&knownGarbagecl);
1.1655 + }
1.1656 +
1.1657 + _collectionSetChooser->sort_regions();
1.1658 +
1.1659 + double end_sec = os::elapsedTime();
1.1660 + double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1.1661 + _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1.1662 + _cur_mark_stop_world_time_ms += elapsed_time_ms;
1.1663 + _prev_collection_pause_end_ms += elapsed_time_ms;
1.1664 + _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true);
1.1665 +}
1.1666 +
1.1667 +// Add the heap region at the head of the non-incremental collection set
1.1668 +void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1.1669 + assert(_inc_cset_build_state == Active, "Precondition");
1.1670 + assert(!hr->is_young(), "non-incremental add of young region");
1.1671 +
1.1672 + assert(!hr->in_collection_set(), "should not already be in the CSet");
1.1673 + hr->set_in_collection_set(true);
1.1674 + hr->set_next_in_collection_set(_collection_set);
1.1675 + _collection_set = hr;
1.1676 + _collection_set_bytes_used_before += hr->used();
1.1677 + _g1->register_region_with_in_cset_fast_test(hr);
1.1678 + size_t rs_length = hr->rem_set()->occupied();
1.1679 + _recorded_rs_lengths += rs_length;
1.1680 + _old_cset_region_length += 1;
1.1681 +}
1.1682 +
1.1683 +// Initialize the per-collection-set information
1.1684 +void G1CollectorPolicy::start_incremental_cset_building() {
1.1685 + assert(_inc_cset_build_state == Inactive, "Precondition");
1.1686 +
1.1687 + _inc_cset_head = NULL;
1.1688 + _inc_cset_tail = NULL;
1.1689 + _inc_cset_bytes_used_before = 0;
1.1690 +
1.1691 + _inc_cset_max_finger = 0;
1.1692 + _inc_cset_recorded_rs_lengths = 0;
1.1693 + _inc_cset_recorded_rs_lengths_diffs = 0;
1.1694 + _inc_cset_predicted_elapsed_time_ms = 0.0;
1.1695 + _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1.1696 + _inc_cset_build_state = Active;
1.1697 +}
1.1698 +
1.1699 +void G1CollectorPolicy::finalize_incremental_cset_building() {
1.1700 + assert(_inc_cset_build_state == Active, "Precondition");
1.1701 + assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1.1702 +
1.1703 + // The two "main" fields, _inc_cset_recorded_rs_lengths and
1.1704 + // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1.1705 + // that adds a new region to the CSet. Further updates by the
1.1706 + // concurrent refinement thread that samples the young RSet lengths
1.1707 + // are accumulated in the *_diffs fields. Here we add the diffs to
1.1708 + // the "main" fields.
1.1709 +
1.1710 + if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1.1711 + _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1.1712 + } else {
1.1713 + // This is defensive. The diff should in theory be always positive
1.1714 + // as RSets can only grow between GCs. However, given that we
1.1715 + // sample their size concurrently with other threads updating them
1.1716 + // it's possible that we might get the wrong size back, which
1.1717 + // could make the calculations somewhat inaccurate.
1.1718 + size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1.1719 + if (_inc_cset_recorded_rs_lengths >= diffs) {
1.1720 + _inc_cset_recorded_rs_lengths -= diffs;
1.1721 + } else {
1.1722 + _inc_cset_recorded_rs_lengths = 0;
1.1723 + }
1.1724 + }
1.1725 + _inc_cset_predicted_elapsed_time_ms +=
1.1726 + _inc_cset_predicted_elapsed_time_ms_diffs;
1.1727 +
1.1728 + _inc_cset_recorded_rs_lengths_diffs = 0;
1.1729 + _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1.1730 +}
1.1731 +
1.1732 +void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1.1733 + // This routine is used when:
1.1734 + // * adding survivor regions to the incremental cset at the end of an
1.1735 + // evacuation pause,
1.1736 + // * adding the current allocation region to the incremental cset
1.1737 + // when it is retired, and
1.1738 + // * updating existing policy information for a region in the
1.1739 + // incremental cset via young list RSet sampling.
1.1740 + // Therefore this routine may be called at a safepoint by the
1.1741 + // VM thread, or in-between safepoints by mutator threads (when
1.1742 + // retiring the current allocation region) or a concurrent
1.1743 + // refine thread (RSet sampling).
1.1744 +
1.1745 + double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1.1746 + size_t used_bytes = hr->used();
1.1747 + _inc_cset_recorded_rs_lengths += rs_length;
1.1748 + _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1.1749 + _inc_cset_bytes_used_before += used_bytes;
1.1750 +
1.1751 + // Cache the values we have added to the aggregated informtion
1.1752 + // in the heap region in case we have to remove this region from
1.1753 + // the incremental collection set, or it is updated by the
1.1754 + // rset sampling code
1.1755 + hr->set_recorded_rs_length(rs_length);
1.1756 + hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1.1757 +}
1.1758 +
1.1759 +void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1.1760 + size_t new_rs_length) {
1.1761 + // Update the CSet information that is dependent on the new RS length
1.1762 + assert(hr->is_young(), "Precondition");
1.1763 + assert(!SafepointSynchronize::is_at_safepoint(),
1.1764 + "should not be at a safepoint");
1.1765 +
1.1766 + // We could have updated _inc_cset_recorded_rs_lengths and
1.1767 + // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1.1768 + // that atomically, as this code is executed by a concurrent
1.1769 + // refinement thread, potentially concurrently with a mutator thread
1.1770 + // allocating a new region and also updating the same fields. To
1.1771 + // avoid the atomic operations we accumulate these updates on two
1.1772 + // separate fields (*_diffs) and we'll just add them to the "main"
1.1773 + // fields at the start of a GC.
1.1774 +
1.1775 + ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1.1776 + ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1.1777 + _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1.1778 +
1.1779 + double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1.1780 + double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1.1781 + double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1.1782 + _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1.1783 +
1.1784 + hr->set_recorded_rs_length(new_rs_length);
1.1785 + hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1.1786 +}
1.1787 +
1.1788 +void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1.1789 + assert(hr->is_young(), "invariant");
1.1790 + assert(hr->young_index_in_cset() > -1, "should have already been set");
1.1791 + assert(_inc_cset_build_state == Active, "Precondition");
1.1792 +
1.1793 + // We need to clear and set the cached recorded/cached collection set
1.1794 + // information in the heap region here (before the region gets added
1.1795 + // to the collection set). An individual heap region's cached values
1.1796 + // are calculated, aggregated with the policy collection set info,
1.1797 + // and cached in the heap region here (initially) and (subsequently)
1.1798 + // by the Young List sampling code.
1.1799 +
1.1800 + size_t rs_length = hr->rem_set()->occupied();
1.1801 + add_to_incremental_cset_info(hr, rs_length);
1.1802 +
1.1803 + HeapWord* hr_end = hr->end();
1.1804 + _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1.1805 +
1.1806 + assert(!hr->in_collection_set(), "invariant");
1.1807 + hr->set_in_collection_set(true);
1.1808 + assert( hr->next_in_collection_set() == NULL, "invariant");
1.1809 +
1.1810 + _g1->register_region_with_in_cset_fast_test(hr);
1.1811 +}
1.1812 +
1.1813 +// Add the region at the RHS of the incremental cset
1.1814 +void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1.1815 + // We should only ever be appending survivors at the end of a pause
1.1816 + assert( hr->is_survivor(), "Logic");
1.1817 +
1.1818 + // Do the 'common' stuff
1.1819 + add_region_to_incremental_cset_common(hr);
1.1820 +
1.1821 + // Now add the region at the right hand side
1.1822 + if (_inc_cset_tail == NULL) {
1.1823 + assert(_inc_cset_head == NULL, "invariant");
1.1824 + _inc_cset_head = hr;
1.1825 + } else {
1.1826 + _inc_cset_tail->set_next_in_collection_set(hr);
1.1827 + }
1.1828 + _inc_cset_tail = hr;
1.1829 +}
1.1830 +
1.1831 +// Add the region to the LHS of the incremental cset
1.1832 +void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1.1833 + // Survivors should be added to the RHS at the end of a pause
1.1834 + assert(!hr->is_survivor(), "Logic");
1.1835 +
1.1836 + // Do the 'common' stuff
1.1837 + add_region_to_incremental_cset_common(hr);
1.1838 +
1.1839 + // Add the region at the left hand side
1.1840 + hr->set_next_in_collection_set(_inc_cset_head);
1.1841 + if (_inc_cset_head == NULL) {
1.1842 + assert(_inc_cset_tail == NULL, "Invariant");
1.1843 + _inc_cset_tail = hr;
1.1844 + }
1.1845 + _inc_cset_head = hr;
1.1846 +}
1.1847 +
1.1848 +#ifndef PRODUCT
1.1849 +void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1.1850 + assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1.1851 +
1.1852 + st->print_cr("\nCollection_set:");
1.1853 + HeapRegion* csr = list_head;
1.1854 + while (csr != NULL) {
1.1855 + HeapRegion* next = csr->next_in_collection_set();
1.1856 + assert(csr->in_collection_set(), "bad CS");
1.1857 + st->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
1.1858 + HR_FORMAT_PARAMS(csr),
1.1859 + csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(),
1.1860 + csr->age_in_surv_rate_group_cond());
1.1861 + csr = next;
1.1862 + }
1.1863 +}
1.1864 +#endif // !PRODUCT
1.1865 +
1.1866 +double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) {
1.1867 + // Returns the given amount of reclaimable bytes (that represents
1.1868 + // the amount of reclaimable space still to be collected) as a
1.1869 + // percentage of the current heap capacity.
1.1870 + size_t capacity_bytes = _g1->capacity();
1.1871 + return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1.1872 +}
1.1873 +
1.1874 +bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1.1875 + const char* false_action_str) {
1.1876 + CollectionSetChooser* cset_chooser = _collectionSetChooser;
1.1877 + if (cset_chooser->is_empty()) {
1.1878 + ergo_verbose0(ErgoMixedGCs,
1.1879 + false_action_str,
1.1880 + ergo_format_reason("candidate old regions not available"));
1.1881 + return false;
1.1882 + }
1.1883 +
1.1884 + // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1.1885 + size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1.1886 + double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1.1887 + double threshold = (double) G1HeapWastePercent;
1.1888 + if (reclaimable_perc <= threshold) {
1.1889 + ergo_verbose4(ErgoMixedGCs,
1.1890 + false_action_str,
1.1891 + ergo_format_reason("reclaimable percentage not over threshold")
1.1892 + ergo_format_region("candidate old regions")
1.1893 + ergo_format_byte_perc("reclaimable")
1.1894 + ergo_format_perc("threshold"),
1.1895 + cset_chooser->remaining_regions(),
1.1896 + reclaimable_bytes,
1.1897 + reclaimable_perc, threshold);
1.1898 + return false;
1.1899 + }
1.1900 +
1.1901 + ergo_verbose4(ErgoMixedGCs,
1.1902 + true_action_str,
1.1903 + ergo_format_reason("candidate old regions available")
1.1904 + ergo_format_region("candidate old regions")
1.1905 + ergo_format_byte_perc("reclaimable")
1.1906 + ergo_format_perc("threshold"),
1.1907 + cset_chooser->remaining_regions(),
1.1908 + reclaimable_bytes,
1.1909 + reclaimable_perc, threshold);
1.1910 + return true;
1.1911 +}
1.1912 +
1.1913 +uint G1CollectorPolicy::calc_min_old_cset_length() {
1.1914 + // The min old CSet region bound is based on the maximum desired
1.1915 + // number of mixed GCs after a cycle. I.e., even if some old regions
1.1916 + // look expensive, we should add them to the CSet anyway to make
1.1917 + // sure we go through the available old regions in no more than the
1.1918 + // maximum desired number of mixed GCs.
1.1919 + //
1.1920 + // The calculation is based on the number of marked regions we added
1.1921 + // to the CSet chooser in the first place, not how many remain, so
1.1922 + // that the result is the same during all mixed GCs that follow a cycle.
1.1923 +
1.1924 + const size_t region_num = (size_t) _collectionSetChooser->length();
1.1925 + const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
1.1926 + size_t result = region_num / gc_num;
1.1927 + // emulate ceiling
1.1928 + if (result * gc_num < region_num) {
1.1929 + result += 1;
1.1930 + }
1.1931 + return (uint) result;
1.1932 +}
1.1933 +
1.1934 +uint G1CollectorPolicy::calc_max_old_cset_length() {
1.1935 + // The max old CSet region bound is based on the threshold expressed
1.1936 + // as a percentage of the heap size. I.e., it should bound the
1.1937 + // number of old regions added to the CSet irrespective of how many
1.1938 + // of them are available.
1.1939 +
1.1940 + G1CollectedHeap* g1h = G1CollectedHeap::heap();
1.1941 + const size_t region_num = g1h->n_regions();
1.1942 + const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
1.1943 + size_t result = region_num * perc / 100;
1.1944 + // emulate ceiling
1.1945 + if (100 * result < region_num * perc) {
1.1946 + result += 1;
1.1947 + }
1.1948 + return (uint) result;
1.1949 +}
1.1950 +
1.1951 +
1.1952 +void G1CollectorPolicy::finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info) {
1.1953 + double young_start_time_sec = os::elapsedTime();
1.1954 +
1.1955 + YoungList* young_list = _g1->young_list();
1.1956 + finalize_incremental_cset_building();
1.1957 +
1.1958 + guarantee(target_pause_time_ms > 0.0,
1.1959 + err_msg("target_pause_time_ms = %1.6lf should be positive",
1.1960 + target_pause_time_ms));
1.1961 + guarantee(_collection_set == NULL, "Precondition");
1.1962 +
1.1963 + double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
1.1964 + double predicted_pause_time_ms = base_time_ms;
1.1965 + double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
1.1966 +
1.1967 + ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
1.1968 + "start choosing CSet",
1.1969 + ergo_format_size("_pending_cards")
1.1970 + ergo_format_ms("predicted base time")
1.1971 + ergo_format_ms("remaining time")
1.1972 + ergo_format_ms("target pause time"),
1.1973 + _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
1.1974 +
1.1975 + _last_gc_was_young = gcs_are_young() ? true : false;
1.1976 +
1.1977 + if (_last_gc_was_young) {
1.1978 + _trace_gen0_time_data.increment_young_collection_count();
1.1979 + } else {
1.1980 + _trace_gen0_time_data.increment_mixed_collection_count();
1.1981 + }
1.1982 +
1.1983 + // The young list is laid with the survivor regions from the previous
1.1984 + // pause are appended to the RHS of the young list, i.e.
1.1985 + // [Newly Young Regions ++ Survivors from last pause].
1.1986 +
1.1987 + uint survivor_region_length = young_list->survivor_length();
1.1988 + uint eden_region_length = young_list->length() - survivor_region_length;
1.1989 + init_cset_region_lengths(eden_region_length, survivor_region_length);
1.1990 +
1.1991 + HeapRegion* hr = young_list->first_survivor_region();
1.1992 + while (hr != NULL) {
1.1993 + assert(hr->is_survivor(), "badly formed young list");
1.1994 + hr->set_young();
1.1995 + hr = hr->get_next_young_region();
1.1996 + }
1.1997 +
1.1998 + // Clear the fields that point to the survivor list - they are all young now.
1.1999 + young_list->clear_survivors();
1.2000 +
1.2001 + _collection_set = _inc_cset_head;
1.2002 + _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
1.2003 + time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
1.2004 + predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
1.2005 +
1.2006 + ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
1.2007 + "add young regions to CSet",
1.2008 + ergo_format_region("eden")
1.2009 + ergo_format_region("survivors")
1.2010 + ergo_format_ms("predicted young region time"),
1.2011 + eden_region_length, survivor_region_length,
1.2012 + _inc_cset_predicted_elapsed_time_ms);
1.2013 +
1.2014 + // The number of recorded young regions is the incremental
1.2015 + // collection set's current size
1.2016 + set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
1.2017 +
1.2018 + double young_end_time_sec = os::elapsedTime();
1.2019 + phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
1.2020 +
1.2021 + // Set the start of the non-young choice time.
1.2022 + double non_young_start_time_sec = young_end_time_sec;
1.2023 +
1.2024 + if (!gcs_are_young()) {
1.2025 + CollectionSetChooser* cset_chooser = _collectionSetChooser;
1.2026 + cset_chooser->verify();
1.2027 + const uint min_old_cset_length = calc_min_old_cset_length();
1.2028 + const uint max_old_cset_length = calc_max_old_cset_length();
1.2029 +
1.2030 + uint expensive_region_num = 0;
1.2031 + bool check_time_remaining = adaptive_young_list_length();
1.2032 +
1.2033 + HeapRegion* hr = cset_chooser->peek();
1.2034 + while (hr != NULL) {
1.2035 + if (old_cset_region_length() >= max_old_cset_length) {
1.2036 + // Added maximum number of old regions to the CSet.
1.2037 + ergo_verbose2(ErgoCSetConstruction,
1.2038 + "finish adding old regions to CSet",
1.2039 + ergo_format_reason("old CSet region num reached max")
1.2040 + ergo_format_region("old")
1.2041 + ergo_format_region("max"),
1.2042 + old_cset_region_length(), max_old_cset_length);
1.2043 + break;
1.2044 + }
1.2045 +
1.2046 +
1.2047 + // Stop adding regions if the remaining reclaimable space is
1.2048 + // not above G1HeapWastePercent.
1.2049 + size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1.2050 + double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1.2051 + double threshold = (double) G1HeapWastePercent;
1.2052 + if (reclaimable_perc <= threshold) {
1.2053 + // We've added enough old regions that the amount of uncollected
1.2054 + // reclaimable space is at or below the waste threshold. Stop
1.2055 + // adding old regions to the CSet.
1.2056 + ergo_verbose5(ErgoCSetConstruction,
1.2057 + "finish adding old regions to CSet",
1.2058 + ergo_format_reason("reclaimable percentage not over threshold")
1.2059 + ergo_format_region("old")
1.2060 + ergo_format_region("max")
1.2061 + ergo_format_byte_perc("reclaimable")
1.2062 + ergo_format_perc("threshold"),
1.2063 + old_cset_region_length(),
1.2064 + max_old_cset_length,
1.2065 + reclaimable_bytes,
1.2066 + reclaimable_perc, threshold);
1.2067 + break;
1.2068 + }
1.2069 +
1.2070 + double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1.2071 + if (check_time_remaining) {
1.2072 + if (predicted_time_ms > time_remaining_ms) {
1.2073 + // Too expensive for the current CSet.
1.2074 +
1.2075 + if (old_cset_region_length() >= min_old_cset_length) {
1.2076 + // We have added the minimum number of old regions to the CSet,
1.2077 + // we are done with this CSet.
1.2078 + ergo_verbose4(ErgoCSetConstruction,
1.2079 + "finish adding old regions to CSet",
1.2080 + ergo_format_reason("predicted time is too high")
1.2081 + ergo_format_ms("predicted time")
1.2082 + ergo_format_ms("remaining time")
1.2083 + ergo_format_region("old")
1.2084 + ergo_format_region("min"),
1.2085 + predicted_time_ms, time_remaining_ms,
1.2086 + old_cset_region_length(), min_old_cset_length);
1.2087 + break;
1.2088 + }
1.2089 +
1.2090 + // We'll add it anyway given that we haven't reached the
1.2091 + // minimum number of old regions.
1.2092 + expensive_region_num += 1;
1.2093 + }
1.2094 + } else {
1.2095 + if (old_cset_region_length() >= min_old_cset_length) {
1.2096 + // In the non-auto-tuning case, we'll finish adding regions
1.2097 + // to the CSet if we reach the minimum.
1.2098 + ergo_verbose2(ErgoCSetConstruction,
1.2099 + "finish adding old regions to CSet",
1.2100 + ergo_format_reason("old CSet region num reached min")
1.2101 + ergo_format_region("old")
1.2102 + ergo_format_region("min"),
1.2103 + old_cset_region_length(), min_old_cset_length);
1.2104 + break;
1.2105 + }
1.2106 + }
1.2107 +
1.2108 + // We will add this region to the CSet.
1.2109 + time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
1.2110 + predicted_pause_time_ms += predicted_time_ms;
1.2111 + cset_chooser->remove_and_move_to_next(hr);
1.2112 + _g1->old_set_remove(hr);
1.2113 + add_old_region_to_cset(hr);
1.2114 +
1.2115 + hr = cset_chooser->peek();
1.2116 + }
1.2117 + if (hr == NULL) {
1.2118 + ergo_verbose0(ErgoCSetConstruction,
1.2119 + "finish adding old regions to CSet",
1.2120 + ergo_format_reason("candidate old regions not available"));
1.2121 + }
1.2122 +
1.2123 + if (expensive_region_num > 0) {
1.2124 + // We print the information once here at the end, predicated on
1.2125 + // whether we added any apparently expensive regions or not, to
1.2126 + // avoid generating output per region.
1.2127 + ergo_verbose4(ErgoCSetConstruction,
1.2128 + "added expensive regions to CSet",
1.2129 + ergo_format_reason("old CSet region num not reached min")
1.2130 + ergo_format_region("old")
1.2131 + ergo_format_region("expensive")
1.2132 + ergo_format_region("min")
1.2133 + ergo_format_ms("remaining time"),
1.2134 + old_cset_region_length(),
1.2135 + expensive_region_num,
1.2136 + min_old_cset_length,
1.2137 + time_remaining_ms);
1.2138 + }
1.2139 +
1.2140 + cset_chooser->verify();
1.2141 + }
1.2142 +
1.2143 + stop_incremental_cset_building();
1.2144 +
1.2145 + ergo_verbose5(ErgoCSetConstruction,
1.2146 + "finish choosing CSet",
1.2147 + ergo_format_region("eden")
1.2148 + ergo_format_region("survivors")
1.2149 + ergo_format_region("old")
1.2150 + ergo_format_ms("predicted pause time")
1.2151 + ergo_format_ms("target pause time"),
1.2152 + eden_region_length, survivor_region_length,
1.2153 + old_cset_region_length(),
1.2154 + predicted_pause_time_ms, target_pause_time_ms);
1.2155 +
1.2156 + double non_young_end_time_sec = os::elapsedTime();
1.2157 + phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
1.2158 + evacuation_info.set_collectionset_regions(cset_region_length());
1.2159 +}
1.2160 +
1.2161 +void TraceGen0TimeData::record_start_collection(double time_to_stop_the_world_ms) {
1.2162 + if(TraceGen0Time) {
1.2163 + _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
1.2164 + }
1.2165 +}
1.2166 +
1.2167 +void TraceGen0TimeData::record_yield_time(double yield_time_ms) {
1.2168 + if(TraceGen0Time) {
1.2169 + _all_yield_times_ms.add(yield_time_ms);
1.2170 + }
1.2171 +}
1.2172 +
1.2173 +void TraceGen0TimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
1.2174 + if(TraceGen0Time) {
1.2175 + _total.add(pause_time_ms);
1.2176 + _other.add(pause_time_ms - phase_times->accounted_time_ms());
1.2177 + _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
1.2178 + _parallel.add(phase_times->cur_collection_par_time_ms());
1.2179 + _ext_root_scan.add(phase_times->average_last_ext_root_scan_time());
1.2180 + _satb_filtering.add(phase_times->average_last_satb_filtering_times_ms());
1.2181 + _update_rs.add(phase_times->average_last_update_rs_time());
1.2182 + _scan_rs.add(phase_times->average_last_scan_rs_time());
1.2183 + _obj_copy.add(phase_times->average_last_obj_copy_time());
1.2184 + _termination.add(phase_times->average_last_termination_time());
1.2185 +
1.2186 + double parallel_known_time = phase_times->average_last_ext_root_scan_time() +
1.2187 + phase_times->average_last_satb_filtering_times_ms() +
1.2188 + phase_times->average_last_update_rs_time() +
1.2189 + phase_times->average_last_scan_rs_time() +
1.2190 + phase_times->average_last_obj_copy_time() +
1.2191 + + phase_times->average_last_termination_time();
1.2192 +
1.2193 + double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
1.2194 + _parallel_other.add(parallel_other_time);
1.2195 + _clear_ct.add(phase_times->cur_clear_ct_time_ms());
1.2196 + }
1.2197 +}
1.2198 +
1.2199 +void TraceGen0TimeData::increment_young_collection_count() {
1.2200 + if(TraceGen0Time) {
1.2201 + ++_young_pause_num;
1.2202 + }
1.2203 +}
1.2204 +
1.2205 +void TraceGen0TimeData::increment_mixed_collection_count() {
1.2206 + if(TraceGen0Time) {
1.2207 + ++_mixed_pause_num;
1.2208 + }
1.2209 +}
1.2210 +
1.2211 +void TraceGen0TimeData::print_summary(const char* str,
1.2212 + const NumberSeq* seq) const {
1.2213 + double sum = seq->sum();
1.2214 + gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
1.2215 + str, sum / 1000.0, seq->avg());
1.2216 +}
1.2217 +
1.2218 +void TraceGen0TimeData::print_summary_sd(const char* str,
1.2219 + const NumberSeq* seq) const {
1.2220 + print_summary(str, seq);
1.2221 + gclog_or_tty->print_cr("%+45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
1.2222 + "(num", seq->num(), seq->sd(), seq->maximum());
1.2223 +}
1.2224 +
1.2225 +void TraceGen0TimeData::print() const {
1.2226 + if (!TraceGen0Time) {
1.2227 + return;
1.2228 + }
1.2229 +
1.2230 + gclog_or_tty->print_cr("ALL PAUSES");
1.2231 + print_summary_sd(" Total", &_total);
1.2232 + gclog_or_tty->cr();
1.2233 + gclog_or_tty->cr();
1.2234 + gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num);
1.2235 + gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num);
1.2236 + gclog_or_tty->cr();
1.2237 +
1.2238 + gclog_or_tty->print_cr("EVACUATION PAUSES");
1.2239 +
1.2240 + if (_young_pause_num == 0 && _mixed_pause_num == 0) {
1.2241 + gclog_or_tty->print_cr("none");
1.2242 + } else {
1.2243 + print_summary_sd(" Evacuation Pauses", &_total);
1.2244 + print_summary(" Root Region Scan Wait", &_root_region_scan_wait);
1.2245 + print_summary(" Parallel Time", &_parallel);
1.2246 + print_summary(" Ext Root Scanning", &_ext_root_scan);
1.2247 + print_summary(" SATB Filtering", &_satb_filtering);
1.2248 + print_summary(" Update RS", &_update_rs);
1.2249 + print_summary(" Scan RS", &_scan_rs);
1.2250 + print_summary(" Object Copy", &_obj_copy);
1.2251 + print_summary(" Termination", &_termination);
1.2252 + print_summary(" Parallel Other", &_parallel_other);
1.2253 + print_summary(" Clear CT", &_clear_ct);
1.2254 + print_summary(" Other", &_other);
1.2255 + }
1.2256 + gclog_or_tty->cr();
1.2257 +
1.2258 + gclog_or_tty->print_cr("MISC");
1.2259 + print_summary_sd(" Stop World", &_all_stop_world_times_ms);
1.2260 + print_summary_sd(" Yields", &_all_yield_times_ms);
1.2261 +}
1.2262 +
1.2263 +void TraceGen1TimeData::record_full_collection(double full_gc_time_ms) {
1.2264 + if (TraceGen1Time) {
1.2265 + _all_full_gc_times.add(full_gc_time_ms);
1.2266 + }
1.2267 +}
1.2268 +
1.2269 +void TraceGen1TimeData::print() const {
1.2270 + if (!TraceGen1Time) {
1.2271 + return;
1.2272 + }
1.2273 +
1.2274 + if (_all_full_gc_times.num() > 0) {
1.2275 + gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
1.2276 + _all_full_gc_times.num(),
1.2277 + _all_full_gc_times.sum() / 1000.0);
1.2278 + gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
1.2279 + gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
1.2280 + _all_full_gc_times.sd(),
1.2281 + _all_full_gc_times.maximum());
1.2282 + }
1.2283 +}
