Mon, 08 Dec 2014 18:57:33 +0100
8067655: Clean up G1 remembered set oop iteration
Summary: Pass on the static type G1ParPushHeapRSClosure to allow oop_iterate devirtualization
Reviewed-by: jmasa, kbarrett
1 /*
2 * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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23 */
25 #ifndef __clang_major__
26 #define ATTRIBUTE_PRINTF(x,y) // FIXME, formats are a mess.
27 #endif
29 #include "precompiled.hpp"
30 #include "gc_implementation/g1/concurrentG1Refine.hpp"
31 #include "gc_implementation/g1/concurrentMark.hpp"
32 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
33 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
34 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
35 #include "gc_implementation/g1/g1ErgoVerbose.hpp"
36 #include "gc_implementation/g1/g1GCPhaseTimes.hpp"
37 #include "gc_implementation/g1/g1Log.hpp"
38 #include "gc_implementation/g1/heapRegionRemSet.hpp"
39 #include "gc_implementation/shared/gcPolicyCounters.hpp"
40 #include "runtime/arguments.hpp"
41 #include "runtime/java.hpp"
42 #include "runtime/mutexLocker.hpp"
43 #include "utilities/debug.hpp"
45 // Different defaults for different number of GC threads
46 // They were chosen by running GCOld and SPECjbb on debris with different
47 // numbers of GC threads and choosing them based on the results
49 // all the same
50 static double rs_length_diff_defaults[] = {
51 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
52 };
54 static double cost_per_card_ms_defaults[] = {
55 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
56 };
58 // all the same
59 static double young_cards_per_entry_ratio_defaults[] = {
60 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
61 };
63 static double cost_per_entry_ms_defaults[] = {
64 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
65 };
67 static double cost_per_byte_ms_defaults[] = {
68 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
69 };
71 // these should be pretty consistent
72 static double constant_other_time_ms_defaults[] = {
73 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
74 };
77 static double young_other_cost_per_region_ms_defaults[] = {
78 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
79 };
81 static double non_young_other_cost_per_region_ms_defaults[] = {
82 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
83 };
85 G1CollectorPolicy::G1CollectorPolicy() :
86 _parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads()
87 ? ParallelGCThreads : 1),
89 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
90 _stop_world_start(0.0),
92 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
93 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
95 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
96 _prev_collection_pause_end_ms(0.0),
97 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
98 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
99 _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
100 _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
101 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
102 _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
103 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
104 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
105 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
106 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
107 _non_young_other_cost_per_region_ms_seq(
108 new TruncatedSeq(TruncatedSeqLength)),
110 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
111 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
113 _pause_time_target_ms((double) MaxGCPauseMillis),
115 _gcs_are_young(true),
117 _during_marking(false),
118 _in_marking_window(false),
119 _in_marking_window_im(false),
121 _recent_prev_end_times_for_all_gcs_sec(
122 new TruncatedSeq(NumPrevPausesForHeuristics)),
124 _recent_avg_pause_time_ratio(0.0),
126 _initiate_conc_mark_if_possible(false),
127 _during_initial_mark_pause(false),
128 _last_young_gc(false),
129 _last_gc_was_young(false),
131 _eden_used_bytes_before_gc(0),
132 _survivor_used_bytes_before_gc(0),
133 _heap_used_bytes_before_gc(0),
134 _metaspace_used_bytes_before_gc(0),
135 _eden_capacity_bytes_before_gc(0),
136 _heap_capacity_bytes_before_gc(0),
138 _eden_cset_region_length(0),
139 _survivor_cset_region_length(0),
140 _old_cset_region_length(0),
142 _collection_set(NULL),
143 _collection_set_bytes_used_before(0),
145 // Incremental CSet attributes
146 _inc_cset_build_state(Inactive),
147 _inc_cset_head(NULL),
148 _inc_cset_tail(NULL),
149 _inc_cset_bytes_used_before(0),
150 _inc_cset_max_finger(NULL),
151 _inc_cset_recorded_rs_lengths(0),
152 _inc_cset_recorded_rs_lengths_diffs(0),
153 _inc_cset_predicted_elapsed_time_ms(0.0),
154 _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
156 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
157 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
158 #endif // _MSC_VER
160 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
161 G1YoungSurvRateNumRegionsSummary)),
162 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
163 G1YoungSurvRateNumRegionsSummary)),
164 // add here any more surv rate groups
165 _recorded_survivor_regions(0),
166 _recorded_survivor_head(NULL),
167 _recorded_survivor_tail(NULL),
168 _survivors_age_table(true),
170 _gc_overhead_perc(0.0) {
172 // Set up the region size and associated fields. Given that the
173 // policy is created before the heap, we have to set this up here,
174 // so it's done as soon as possible.
176 // It would have been natural to pass initial_heap_byte_size() and
177 // max_heap_byte_size() to setup_heap_region_size() but those have
178 // not been set up at this point since they should be aligned with
179 // the region size. So, there is a circular dependency here. We base
180 // the region size on the heap size, but the heap size should be
181 // aligned with the region size. To get around this we use the
182 // unaligned values for the heap.
183 HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
184 HeapRegionRemSet::setup_remset_size();
186 G1ErgoVerbose::initialize();
187 if (PrintAdaptiveSizePolicy) {
188 // Currently, we only use a single switch for all the heuristics.
189 G1ErgoVerbose::set_enabled(true);
190 // Given that we don't currently have a verboseness level
191 // parameter, we'll hardcode this to high. This can be easily
192 // changed in the future.
193 G1ErgoVerbose::set_level(ErgoHigh);
194 } else {
195 G1ErgoVerbose::set_enabled(false);
196 }
198 // Verify PLAB sizes
199 const size_t region_size = HeapRegion::GrainWords;
200 if (YoungPLABSize > region_size || OldPLABSize > region_size) {
201 char buffer[128];
202 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT,
203 OldPLABSize > region_size ? "Old" : "Young", region_size);
204 vm_exit_during_initialization(buffer);
205 }
207 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
208 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
210 _phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
212 int index = MIN2(_parallel_gc_threads - 1, 7);
214 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
215 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
216 _young_cards_per_entry_ratio_seq->add(
217 young_cards_per_entry_ratio_defaults[index]);
218 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
219 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
220 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
221 _young_other_cost_per_region_ms_seq->add(
222 young_other_cost_per_region_ms_defaults[index]);
223 _non_young_other_cost_per_region_ms_seq->add(
224 non_young_other_cost_per_region_ms_defaults[index]);
226 // Below, we might need to calculate the pause time target based on
227 // the pause interval. When we do so we are going to give G1 maximum
228 // flexibility and allow it to do pauses when it needs to. So, we'll
229 // arrange that the pause interval to be pause time target + 1 to
230 // ensure that a) the pause time target is maximized with respect to
231 // the pause interval and b) we maintain the invariant that pause
232 // time target < pause interval. If the user does not want this
233 // maximum flexibility, they will have to set the pause interval
234 // explicitly.
236 // First make sure that, if either parameter is set, its value is
237 // reasonable.
238 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
239 if (MaxGCPauseMillis < 1) {
240 vm_exit_during_initialization("MaxGCPauseMillis should be "
241 "greater than 0");
242 }
243 }
244 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
245 if (GCPauseIntervalMillis < 1) {
246 vm_exit_during_initialization("GCPauseIntervalMillis should be "
247 "greater than 0");
248 }
249 }
251 // Then, if the pause time target parameter was not set, set it to
252 // the default value.
253 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
254 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
255 // The default pause time target in G1 is 200ms
256 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
257 } else {
258 // We do not allow the pause interval to be set without the
259 // pause time target
260 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
261 "without setting MaxGCPauseMillis");
262 }
263 }
265 // Then, if the interval parameter was not set, set it according to
266 // the pause time target (this will also deal with the case when the
267 // pause time target is the default value).
268 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
269 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
270 }
272 // Finally, make sure that the two parameters are consistent.
273 if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
274 char buffer[256];
275 jio_snprintf(buffer, 256,
276 "MaxGCPauseMillis (%u) should be less than "
277 "GCPauseIntervalMillis (%u)",
278 MaxGCPauseMillis, GCPauseIntervalMillis);
279 vm_exit_during_initialization(buffer);
280 }
282 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
283 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
284 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
286 uintx confidence_perc = G1ConfidencePercent;
287 // Put an artificial ceiling on this so that it's not set to a silly value.
288 if (confidence_perc > 100) {
289 confidence_perc = 100;
290 warning("G1ConfidencePercent is set to a value that is too large, "
291 "it's been updated to %u", confidence_perc);
292 }
293 _sigma = (double) confidence_perc / 100.0;
295 // start conservatively (around 50ms is about right)
296 _concurrent_mark_remark_times_ms->add(0.05);
297 _concurrent_mark_cleanup_times_ms->add(0.20);
298 _tenuring_threshold = MaxTenuringThreshold;
299 // _max_survivor_regions will be calculated by
300 // update_young_list_target_length() during initialization.
301 _max_survivor_regions = 0;
303 assert(GCTimeRatio > 0,
304 "we should have set it to a default value set_g1_gc_flags() "
305 "if a user set it to 0");
306 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
308 uintx reserve_perc = G1ReservePercent;
309 // Put an artificial ceiling on this so that it's not set to a silly value.
310 if (reserve_perc > 50) {
311 reserve_perc = 50;
312 warning("G1ReservePercent is set to a value that is too large, "
313 "it's been updated to %u", reserve_perc);
314 }
315 _reserve_factor = (double) reserve_perc / 100.0;
316 // This will be set when the heap is expanded
317 // for the first time during initialization.
318 _reserve_regions = 0;
320 _collectionSetChooser = new CollectionSetChooser();
321 }
323 void G1CollectorPolicy::initialize_alignments() {
324 _space_alignment = HeapRegion::GrainBytes;
325 size_t card_table_alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
326 size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
327 _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
328 }
330 void G1CollectorPolicy::initialize_flags() {
331 if (G1HeapRegionSize != HeapRegion::GrainBytes) {
332 FLAG_SET_ERGO(uintx, G1HeapRegionSize, HeapRegion::GrainBytes);
333 }
335 if (SurvivorRatio < 1) {
336 vm_exit_during_initialization("Invalid survivor ratio specified");
337 }
338 CollectorPolicy::initialize_flags();
339 _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
340 }
342 void G1CollectorPolicy::post_heap_initialize() {
343 uintx max_regions = G1CollectedHeap::heap()->max_regions();
344 size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
345 if (max_young_size != MaxNewSize) {
346 FLAG_SET_ERGO(uintx, MaxNewSize, max_young_size);
347 }
348 }
350 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
351 _min_desired_young_length(0), _max_desired_young_length(0) {
352 if (FLAG_IS_CMDLINE(NewRatio)) {
353 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
354 warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
355 } else {
356 _sizer_kind = SizerNewRatio;
357 _adaptive_size = false;
358 return;
359 }
360 }
362 if (NewSize > MaxNewSize) {
363 if (FLAG_IS_CMDLINE(MaxNewSize)) {
364 warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
365 "A new max generation size of " SIZE_FORMAT "k will be used.",
366 NewSize/K, MaxNewSize/K, NewSize/K);
367 }
368 MaxNewSize = NewSize;
369 }
371 if (FLAG_IS_CMDLINE(NewSize)) {
372 _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
373 1U);
374 if (FLAG_IS_CMDLINE(MaxNewSize)) {
375 _max_desired_young_length =
376 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
377 1U);
378 _sizer_kind = SizerMaxAndNewSize;
379 _adaptive_size = _min_desired_young_length == _max_desired_young_length;
380 } else {
381 _sizer_kind = SizerNewSizeOnly;
382 }
383 } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
384 _max_desired_young_length =
385 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
386 1U);
387 _sizer_kind = SizerMaxNewSizeOnly;
388 }
389 }
391 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
392 uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
393 return MAX2(1U, default_value);
394 }
396 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
397 uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
398 return MAX2(1U, default_value);
399 }
401 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
402 assert(number_of_heap_regions > 0, "Heap must be initialized");
404 switch (_sizer_kind) {
405 case SizerDefaults:
406 *min_young_length = calculate_default_min_length(number_of_heap_regions);
407 *max_young_length = calculate_default_max_length(number_of_heap_regions);
408 break;
409 case SizerNewSizeOnly:
410 *max_young_length = calculate_default_max_length(number_of_heap_regions);
411 *max_young_length = MAX2(*min_young_length, *max_young_length);
412 break;
413 case SizerMaxNewSizeOnly:
414 *min_young_length = calculate_default_min_length(number_of_heap_regions);
415 *min_young_length = MIN2(*min_young_length, *max_young_length);
416 break;
417 case SizerMaxAndNewSize:
418 // Do nothing. Values set on the command line, don't update them at runtime.
419 break;
420 case SizerNewRatio:
421 *min_young_length = number_of_heap_regions / (NewRatio + 1);
422 *max_young_length = *min_young_length;
423 break;
424 default:
425 ShouldNotReachHere();
426 }
428 assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
429 }
431 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
432 // We need to pass the desired values because recalculation may not update these
433 // values in some cases.
434 uint temp = _min_desired_young_length;
435 uint result = _max_desired_young_length;
436 recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
437 return result;
438 }
440 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
441 recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
442 &_max_desired_young_length);
443 }
445 void G1CollectorPolicy::init() {
446 // Set aside an initial future to_space.
447 _g1 = G1CollectedHeap::heap();
449 assert(Heap_lock->owned_by_self(), "Locking discipline.");
451 initialize_gc_policy_counters();
453 if (adaptive_young_list_length()) {
454 _young_list_fixed_length = 0;
455 } else {
456 _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
457 }
458 _free_regions_at_end_of_collection = _g1->num_free_regions();
459 update_young_list_target_length();
461 // We may immediately start allocating regions and placing them on the
462 // collection set list. Initialize the per-collection set info
463 start_incremental_cset_building();
464 }
466 // Create the jstat counters for the policy.
467 void G1CollectorPolicy::initialize_gc_policy_counters() {
468 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
469 }
471 bool G1CollectorPolicy::predict_will_fit(uint young_length,
472 double base_time_ms,
473 uint base_free_regions,
474 double target_pause_time_ms) {
475 if (young_length >= base_free_regions) {
476 // end condition 1: not enough space for the young regions
477 return false;
478 }
480 double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
481 size_t bytes_to_copy =
482 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
483 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
484 double young_other_time_ms = predict_young_other_time_ms(young_length);
485 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
486 if (pause_time_ms > target_pause_time_ms) {
487 // end condition 2: prediction is over the target pause time
488 return false;
489 }
491 size_t free_bytes =
492 (base_free_regions - young_length) * HeapRegion::GrainBytes;
493 if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
494 // end condition 3: out-of-space (conservatively!)
495 return false;
496 }
498 // success!
499 return true;
500 }
502 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
503 // re-calculate the necessary reserve
504 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
505 // We use ceiling so that if reserve_regions_d is > 0.0 (but
506 // smaller than 1.0) we'll get 1.
507 _reserve_regions = (uint) ceil(reserve_regions_d);
509 _young_gen_sizer->heap_size_changed(new_number_of_regions);
510 }
512 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
513 uint base_min_length) {
514 uint desired_min_length = 0;
515 if (adaptive_young_list_length()) {
516 if (_alloc_rate_ms_seq->num() > 3) {
517 double now_sec = os::elapsedTime();
518 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
519 double alloc_rate_ms = predict_alloc_rate_ms();
520 desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
521 } else {
522 // otherwise we don't have enough info to make the prediction
523 }
524 }
525 desired_min_length += base_min_length;
526 // make sure we don't go below any user-defined minimum bound
527 return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
528 }
530 uint G1CollectorPolicy::calculate_young_list_desired_max_length() {
531 // Here, we might want to also take into account any additional
532 // constraints (i.e., user-defined minimum bound). Currently, we
533 // effectively don't set this bound.
534 return _young_gen_sizer->max_desired_young_length();
535 }
537 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
538 if (rs_lengths == (size_t) -1) {
539 // if it's set to the default value (-1), we should predict it;
540 // otherwise, use the given value.
541 rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
542 }
544 // Calculate the absolute and desired min bounds.
546 // This is how many young regions we already have (currently: the survivors).
547 uint base_min_length = recorded_survivor_regions();
548 // This is the absolute minimum young length, which ensures that we
549 // can allocate one eden region in the worst-case.
550 uint absolute_min_length = base_min_length + 1;
551 uint desired_min_length =
552 calculate_young_list_desired_min_length(base_min_length);
553 if (desired_min_length < absolute_min_length) {
554 desired_min_length = absolute_min_length;
555 }
557 // Calculate the absolute and desired max bounds.
559 // We will try our best not to "eat" into the reserve.
560 uint absolute_max_length = 0;
561 if (_free_regions_at_end_of_collection > _reserve_regions) {
562 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
563 }
564 uint desired_max_length = calculate_young_list_desired_max_length();
565 if (desired_max_length > absolute_max_length) {
566 desired_max_length = absolute_max_length;
567 }
569 uint young_list_target_length = 0;
570 if (adaptive_young_list_length()) {
571 if (gcs_are_young()) {
572 young_list_target_length =
573 calculate_young_list_target_length(rs_lengths,
574 base_min_length,
575 desired_min_length,
576 desired_max_length);
577 _rs_lengths_prediction = rs_lengths;
578 } else {
579 // Don't calculate anything and let the code below bound it to
580 // the desired_min_length, i.e., do the next GC as soon as
581 // possible to maximize how many old regions we can add to it.
582 }
583 } else {
584 // The user asked for a fixed young gen so we'll fix the young gen
585 // whether the next GC is young or mixed.
586 young_list_target_length = _young_list_fixed_length;
587 }
589 // Make sure we don't go over the desired max length, nor under the
590 // desired min length. In case they clash, desired_min_length wins
591 // which is why that test is second.
592 if (young_list_target_length > desired_max_length) {
593 young_list_target_length = desired_max_length;
594 }
595 if (young_list_target_length < desired_min_length) {
596 young_list_target_length = desired_min_length;
597 }
599 assert(young_list_target_length > recorded_survivor_regions(),
600 "we should be able to allocate at least one eden region");
601 assert(young_list_target_length >= absolute_min_length, "post-condition");
602 _young_list_target_length = young_list_target_length;
604 update_max_gc_locker_expansion();
605 }
607 uint
608 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
609 uint base_min_length,
610 uint desired_min_length,
611 uint desired_max_length) {
612 assert(adaptive_young_list_length(), "pre-condition");
613 assert(gcs_are_young(), "only call this for young GCs");
615 // In case some edge-condition makes the desired max length too small...
616 if (desired_max_length <= desired_min_length) {
617 return desired_min_length;
618 }
620 // We'll adjust min_young_length and max_young_length not to include
621 // the already allocated young regions (i.e., so they reflect the
622 // min and max eden regions we'll allocate). The base_min_length
623 // will be reflected in the predictions by the
624 // survivor_regions_evac_time prediction.
625 assert(desired_min_length > base_min_length, "invariant");
626 uint min_young_length = desired_min_length - base_min_length;
627 assert(desired_max_length > base_min_length, "invariant");
628 uint max_young_length = desired_max_length - base_min_length;
630 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
631 double survivor_regions_evac_time = predict_survivor_regions_evac_time();
632 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
633 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
634 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
635 double base_time_ms =
636 predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
637 survivor_regions_evac_time;
638 uint available_free_regions = _free_regions_at_end_of_collection;
639 uint base_free_regions = 0;
640 if (available_free_regions > _reserve_regions) {
641 base_free_regions = available_free_regions - _reserve_regions;
642 }
644 // Here, we will make sure that the shortest young length that
645 // makes sense fits within the target pause time.
647 if (predict_will_fit(min_young_length, base_time_ms,
648 base_free_regions, target_pause_time_ms)) {
649 // The shortest young length will fit into the target pause time;
650 // we'll now check whether the absolute maximum number of young
651 // regions will fit in the target pause time. If not, we'll do
652 // a binary search between min_young_length and max_young_length.
653 if (predict_will_fit(max_young_length, base_time_ms,
654 base_free_regions, target_pause_time_ms)) {
655 // The maximum young length will fit into the target pause time.
656 // We are done so set min young length to the maximum length (as
657 // the result is assumed to be returned in min_young_length).
658 min_young_length = max_young_length;
659 } else {
660 // The maximum possible number of young regions will not fit within
661 // the target pause time so we'll search for the optimal
662 // length. The loop invariants are:
663 //
664 // min_young_length < max_young_length
665 // min_young_length is known to fit into the target pause time
666 // max_young_length is known not to fit into the target pause time
667 //
668 // Going into the loop we know the above hold as we've just
669 // checked them. Every time around the loop we check whether
670 // the middle value between min_young_length and
671 // max_young_length fits into the target pause time. If it
672 // does, it becomes the new min. If it doesn't, it becomes
673 // the new max. This way we maintain the loop invariants.
675 assert(min_young_length < max_young_length, "invariant");
676 uint diff = (max_young_length - min_young_length) / 2;
677 while (diff > 0) {
678 uint young_length = min_young_length + diff;
679 if (predict_will_fit(young_length, base_time_ms,
680 base_free_regions, target_pause_time_ms)) {
681 min_young_length = young_length;
682 } else {
683 max_young_length = young_length;
684 }
685 assert(min_young_length < max_young_length, "invariant");
686 diff = (max_young_length - min_young_length) / 2;
687 }
688 // The results is min_young_length which, according to the
689 // loop invariants, should fit within the target pause time.
691 // These are the post-conditions of the binary search above:
692 assert(min_young_length < max_young_length,
693 "otherwise we should have discovered that max_young_length "
694 "fits into the pause target and not done the binary search");
695 assert(predict_will_fit(min_young_length, base_time_ms,
696 base_free_regions, target_pause_time_ms),
697 "min_young_length, the result of the binary search, should "
698 "fit into the pause target");
699 assert(!predict_will_fit(min_young_length + 1, base_time_ms,
700 base_free_regions, target_pause_time_ms),
701 "min_young_length, the result of the binary search, should be "
702 "optimal, so no larger length should fit into the pause target");
703 }
704 } else {
705 // Even the minimum length doesn't fit into the pause time
706 // target, return it as the result nevertheless.
707 }
708 return base_min_length + min_young_length;
709 }
711 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
712 double survivor_regions_evac_time = 0.0;
713 for (HeapRegion * r = _recorded_survivor_head;
714 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
715 r = r->get_next_young_region()) {
716 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young());
717 }
718 return survivor_regions_evac_time;
719 }
721 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
722 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
724 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
725 if (rs_lengths > _rs_lengths_prediction) {
726 // add 10% to avoid having to recalculate often
727 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
728 update_young_list_target_length(rs_lengths_prediction);
729 }
730 }
734 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
735 bool is_tlab,
736 bool* gc_overhead_limit_was_exceeded) {
737 guarantee(false, "Not using this policy feature yet.");
738 return NULL;
739 }
741 // This method controls how a collector handles one or more
742 // of its generations being fully allocated.
743 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
744 bool is_tlab) {
745 guarantee(false, "Not using this policy feature yet.");
746 return NULL;
747 }
750 #ifndef PRODUCT
751 bool G1CollectorPolicy::verify_young_ages() {
752 HeapRegion* head = _g1->young_list()->first_region();
753 return
754 verify_young_ages(head, _short_lived_surv_rate_group);
755 // also call verify_young_ages on any additional surv rate groups
756 }
758 bool
759 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
760 SurvRateGroup *surv_rate_group) {
761 guarantee( surv_rate_group != NULL, "pre-condition" );
763 const char* name = surv_rate_group->name();
764 bool ret = true;
765 int prev_age = -1;
767 for (HeapRegion* curr = head;
768 curr != NULL;
769 curr = curr->get_next_young_region()) {
770 SurvRateGroup* group = curr->surv_rate_group();
771 if (group == NULL && !curr->is_survivor()) {
772 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
773 ret = false;
774 }
776 if (surv_rate_group == group) {
777 int age = curr->age_in_surv_rate_group();
779 if (age < 0) {
780 gclog_or_tty->print_cr("## %s: encountered negative age", name);
781 ret = false;
782 }
784 if (age <= prev_age) {
785 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
786 "(%d, %d)", name, age, prev_age);
787 ret = false;
788 }
789 prev_age = age;
790 }
791 }
793 return ret;
794 }
795 #endif // PRODUCT
797 void G1CollectorPolicy::record_full_collection_start() {
798 _full_collection_start_sec = os::elapsedTime();
799 record_heap_size_info_at_start(true /* full */);
800 // Release the future to-space so that it is available for compaction into.
801 _g1->set_full_collection();
802 }
804 void G1CollectorPolicy::record_full_collection_end() {
805 // Consider this like a collection pause for the purposes of allocation
806 // since last pause.
807 double end_sec = os::elapsedTime();
808 double full_gc_time_sec = end_sec - _full_collection_start_sec;
809 double full_gc_time_ms = full_gc_time_sec * 1000.0;
811 _trace_gen1_time_data.record_full_collection(full_gc_time_ms);
813 update_recent_gc_times(end_sec, full_gc_time_ms);
815 _g1->clear_full_collection();
817 // "Nuke" the heuristics that control the young/mixed GC
818 // transitions and make sure we start with young GCs after the Full GC.
819 set_gcs_are_young(true);
820 _last_young_gc = false;
821 clear_initiate_conc_mark_if_possible();
822 clear_during_initial_mark_pause();
823 _in_marking_window = false;
824 _in_marking_window_im = false;
826 _short_lived_surv_rate_group->start_adding_regions();
827 // also call this on any additional surv rate groups
829 record_survivor_regions(0, NULL, NULL);
831 _free_regions_at_end_of_collection = _g1->num_free_regions();
832 // Reset survivors SurvRateGroup.
833 _survivor_surv_rate_group->reset();
834 update_young_list_target_length();
835 _collectionSetChooser->clear();
836 }
838 void G1CollectorPolicy::record_stop_world_start() {
839 _stop_world_start = os::elapsedTime();
840 }
842 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
843 // We only need to do this here as the policy will only be applied
844 // to the GC we're about to start. so, no point is calculating this
845 // every time we calculate / recalculate the target young length.
846 update_survivors_policy();
848 assert(_g1->used() == _g1->recalculate_used(),
849 err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
850 _g1->used(), _g1->recalculate_used()));
852 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
853 _trace_gen0_time_data.record_start_collection(s_w_t_ms);
854 _stop_world_start = 0.0;
856 record_heap_size_info_at_start(false /* full */);
858 phase_times()->record_cur_collection_start_sec(start_time_sec);
859 _pending_cards = _g1->pending_card_num();
861 _collection_set_bytes_used_before = 0;
862 _bytes_copied_during_gc = 0;
864 _last_gc_was_young = false;
866 // do that for any other surv rate groups
867 _short_lived_surv_rate_group->stop_adding_regions();
868 _survivors_age_table.clear();
870 assert( verify_young_ages(), "region age verification" );
871 }
873 void G1CollectorPolicy::record_concurrent_mark_init_end(double
874 mark_init_elapsed_time_ms) {
875 _during_marking = true;
876 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
877 clear_during_initial_mark_pause();
878 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
879 }
881 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
882 _mark_remark_start_sec = os::elapsedTime();
883 _during_marking = false;
884 }
886 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
887 double end_time_sec = os::elapsedTime();
888 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
889 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
890 _cur_mark_stop_world_time_ms += elapsed_time_ms;
891 _prev_collection_pause_end_ms += elapsed_time_ms;
893 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
894 }
896 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
897 _mark_cleanup_start_sec = os::elapsedTime();
898 }
900 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
901 _last_young_gc = true;
902 _in_marking_window = false;
903 }
905 void G1CollectorPolicy::record_concurrent_pause() {
906 if (_stop_world_start > 0.0) {
907 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
908 _trace_gen0_time_data.record_yield_time(yield_ms);
909 }
910 }
912 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
913 if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
914 return false;
915 }
917 size_t marking_initiating_used_threshold =
918 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
919 size_t cur_used_bytes = _g1->non_young_capacity_bytes();
920 size_t alloc_byte_size = alloc_word_size * HeapWordSize;
922 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
923 if (gcs_are_young() && !_last_young_gc) {
924 ergo_verbose5(ErgoConcCycles,
925 "request concurrent cycle initiation",
926 ergo_format_reason("occupancy higher than threshold")
927 ergo_format_byte("occupancy")
928 ergo_format_byte("allocation request")
929 ergo_format_byte_perc("threshold")
930 ergo_format_str("source"),
931 cur_used_bytes,
932 alloc_byte_size,
933 marking_initiating_used_threshold,
934 (double) InitiatingHeapOccupancyPercent,
935 source);
936 return true;
937 } else {
938 ergo_verbose5(ErgoConcCycles,
939 "do not request concurrent cycle initiation",
940 ergo_format_reason("still doing mixed collections")
941 ergo_format_byte("occupancy")
942 ergo_format_byte("allocation request")
943 ergo_format_byte_perc("threshold")
944 ergo_format_str("source"),
945 cur_used_bytes,
946 alloc_byte_size,
947 marking_initiating_used_threshold,
948 (double) InitiatingHeapOccupancyPercent,
949 source);
950 }
951 }
953 return false;
954 }
956 // Anything below that is considered to be zero
957 #define MIN_TIMER_GRANULARITY 0.0000001
959 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info) {
960 double end_time_sec = os::elapsedTime();
961 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
962 "otherwise, the subtraction below does not make sense");
963 size_t rs_size =
964 _cur_collection_pause_used_regions_at_start - cset_region_length();
965 size_t cur_used_bytes = _g1->used();
966 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
967 bool last_pause_included_initial_mark = false;
968 bool update_stats = !_g1->evacuation_failed();
970 #ifndef PRODUCT
971 if (G1YoungSurvRateVerbose) {
972 gclog_or_tty->cr();
973 _short_lived_surv_rate_group->print();
974 // do that for any other surv rate groups too
975 }
976 #endif // PRODUCT
978 last_pause_included_initial_mark = during_initial_mark_pause();
979 if (last_pause_included_initial_mark) {
980 record_concurrent_mark_init_end(0.0);
981 } else if (need_to_start_conc_mark("end of GC")) {
982 // Note: this might have already been set, if during the last
983 // pause we decided to start a cycle but at the beginning of
984 // this pause we decided to postpone it. That's OK.
985 set_initiate_conc_mark_if_possible();
986 }
988 _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0,
989 end_time_sec, false);
991 evacuation_info.set_collectionset_used_before(_collection_set_bytes_used_before);
992 evacuation_info.set_bytes_copied(_bytes_copied_during_gc);
994 if (update_stats) {
995 _trace_gen0_time_data.record_end_collection(pause_time_ms, phase_times());
996 // this is where we update the allocation rate of the application
997 double app_time_ms =
998 (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
999 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1000 // This usually happens due to the timer not having the required
1001 // granularity. Some Linuxes are the usual culprits.
1002 // We'll just set it to something (arbitrarily) small.
1003 app_time_ms = 1.0;
1004 }
1005 // We maintain the invariant that all objects allocated by mutator
1006 // threads will be allocated out of eden regions. So, we can use
1007 // the eden region number allocated since the previous GC to
1008 // calculate the application's allocate rate. The only exception
1009 // to that is humongous objects that are allocated separately. But
1010 // given that humongous object allocations do not really affect
1011 // either the pause's duration nor when the next pause will take
1012 // place we can safely ignore them here.
1013 uint regions_allocated = eden_cset_region_length();
1014 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1015 _alloc_rate_ms_seq->add(alloc_rate_ms);
1017 double interval_ms =
1018 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1019 update_recent_gc_times(end_time_sec, pause_time_ms);
1020 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1021 if (recent_avg_pause_time_ratio() < 0.0 ||
1022 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1023 #ifndef PRODUCT
1024 // Dump info to allow post-facto debugging
1025 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1026 gclog_or_tty->print_cr("-------------------------------------------");
1027 gclog_or_tty->print_cr("Recent GC Times (ms):");
1028 _recent_gc_times_ms->dump();
1029 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1030 _recent_prev_end_times_for_all_gcs_sec->dump();
1031 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1032 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1033 // In debug mode, terminate the JVM if the user wants to debug at this point.
1034 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1035 #endif // !PRODUCT
1036 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1037 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1038 if (_recent_avg_pause_time_ratio < 0.0) {
1039 _recent_avg_pause_time_ratio = 0.0;
1040 } else {
1041 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1042 _recent_avg_pause_time_ratio = 1.0;
1043 }
1044 }
1045 }
1047 bool new_in_marking_window = _in_marking_window;
1048 bool new_in_marking_window_im = false;
1049 if (last_pause_included_initial_mark) {
1050 new_in_marking_window = true;
1051 new_in_marking_window_im = true;
1052 }
1054 if (_last_young_gc) {
1055 // This is supposed to to be the "last young GC" before we start
1056 // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1058 if (!last_pause_included_initial_mark) {
1059 if (next_gc_should_be_mixed("start mixed GCs",
1060 "do not start mixed GCs")) {
1061 set_gcs_are_young(false);
1062 }
1063 } else {
1064 ergo_verbose0(ErgoMixedGCs,
1065 "do not start mixed GCs",
1066 ergo_format_reason("concurrent cycle is about to start"));
1067 }
1068 _last_young_gc = false;
1069 }
1071 if (!_last_gc_was_young) {
1072 // This is a mixed GC. Here we decide whether to continue doing
1073 // mixed GCs or not.
1075 if (!next_gc_should_be_mixed("continue mixed GCs",
1076 "do not continue mixed GCs")) {
1077 set_gcs_are_young(true);
1078 }
1079 }
1081 _short_lived_surv_rate_group->start_adding_regions();
1082 // do that for any other surv rate groupsx
1084 if (update_stats) {
1085 double cost_per_card_ms = 0.0;
1086 if (_pending_cards > 0) {
1087 cost_per_card_ms = phase_times()->average_last_update_rs_time() / (double) _pending_cards;
1088 _cost_per_card_ms_seq->add(cost_per_card_ms);
1089 }
1091 size_t cards_scanned = _g1->cards_scanned();
1093 double cost_per_entry_ms = 0.0;
1094 if (cards_scanned > 10) {
1095 cost_per_entry_ms = phase_times()->average_last_scan_rs_time() / (double) cards_scanned;
1096 if (_last_gc_was_young) {
1097 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1098 } else {
1099 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1100 }
1101 }
1103 if (_max_rs_lengths > 0) {
1104 double cards_per_entry_ratio =
1105 (double) cards_scanned / (double) _max_rs_lengths;
1106 if (_last_gc_was_young) {
1107 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1108 } else {
1109 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1110 }
1111 }
1113 // This is defensive. For a while _max_rs_lengths could get
1114 // smaller than _recorded_rs_lengths which was causing
1115 // rs_length_diff to get very large and mess up the RSet length
1116 // predictions. The reason was unsafe concurrent updates to the
1117 // _inc_cset_recorded_rs_lengths field which the code below guards
1118 // against (see CR 7118202). This bug has now been fixed (see CR
1119 // 7119027). However, I'm still worried that
1120 // _inc_cset_recorded_rs_lengths might still end up somewhat
1121 // inaccurate. The concurrent refinement thread calculates an
1122 // RSet's length concurrently with other CR threads updating it
1123 // which might cause it to calculate the length incorrectly (if,
1124 // say, it's in mid-coarsening). So I'll leave in the defensive
1125 // conditional below just in case.
1126 size_t rs_length_diff = 0;
1127 if (_max_rs_lengths > _recorded_rs_lengths) {
1128 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1129 }
1130 _rs_length_diff_seq->add((double) rs_length_diff);
1132 size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1133 size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1134 double cost_per_byte_ms = 0.0;
1136 if (copied_bytes > 0) {
1137 cost_per_byte_ms = phase_times()->average_last_obj_copy_time() / (double) copied_bytes;
1138 if (_in_marking_window) {
1139 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1140 } else {
1141 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1142 }
1143 }
1145 double all_other_time_ms = pause_time_ms -
1146 (phase_times()->average_last_update_rs_time() + phase_times()->average_last_scan_rs_time()
1147 + phase_times()->average_last_obj_copy_time() + phase_times()->average_last_termination_time());
1149 double young_other_time_ms = 0.0;
1150 if (young_cset_region_length() > 0) {
1151 young_other_time_ms =
1152 phase_times()->young_cset_choice_time_ms() +
1153 phase_times()->young_free_cset_time_ms();
1154 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1155 (double) young_cset_region_length());
1156 }
1157 double non_young_other_time_ms = 0.0;
1158 if (old_cset_region_length() > 0) {
1159 non_young_other_time_ms =
1160 phase_times()->non_young_cset_choice_time_ms() +
1161 phase_times()->non_young_free_cset_time_ms();
1163 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1164 (double) old_cset_region_length());
1165 }
1167 double constant_other_time_ms = all_other_time_ms -
1168 (young_other_time_ms + non_young_other_time_ms);
1169 _constant_other_time_ms_seq->add(constant_other_time_ms);
1171 double survival_ratio = 0.0;
1172 if (_collection_set_bytes_used_before > 0) {
1173 survival_ratio = (double) _bytes_copied_during_gc /
1174 (double) _collection_set_bytes_used_before;
1175 }
1177 _pending_cards_seq->add((double) _pending_cards);
1178 _rs_lengths_seq->add((double) _max_rs_lengths);
1179 }
1181 _in_marking_window = new_in_marking_window;
1182 _in_marking_window_im = new_in_marking_window_im;
1183 _free_regions_at_end_of_collection = _g1->num_free_regions();
1184 update_young_list_target_length();
1186 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1187 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1188 adjust_concurrent_refinement(phase_times()->average_last_update_rs_time(),
1189 phase_times()->sum_last_update_rs_processed_buffers(), update_rs_time_goal_ms);
1191 _collectionSetChooser->verify();
1192 }
1194 #define EXT_SIZE_FORMAT "%.1f%s"
1195 #define EXT_SIZE_PARAMS(bytes) \
1196 byte_size_in_proper_unit((double)(bytes)), \
1197 proper_unit_for_byte_size((bytes))
1199 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1200 YoungList* young_list = _g1->young_list();
1201 _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1202 _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1203 _heap_capacity_bytes_before_gc = _g1->capacity();
1204 _heap_used_bytes_before_gc = _g1->used();
1205 _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1207 _eden_capacity_bytes_before_gc =
1208 (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1210 if (full) {
1211 _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1212 }
1213 }
1215 void G1CollectorPolicy::print_heap_transition() {
1216 _g1->print_size_transition(gclog_or_tty,
1217 _heap_used_bytes_before_gc,
1218 _g1->used(),
1219 _g1->capacity());
1220 }
1222 void G1CollectorPolicy::print_detailed_heap_transition(bool full) {
1223 YoungList* young_list = _g1->young_list();
1225 size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1226 size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1227 size_t heap_used_bytes_after_gc = _g1->used();
1229 size_t heap_capacity_bytes_after_gc = _g1->capacity();
1230 size_t eden_capacity_bytes_after_gc =
1231 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1233 gclog_or_tty->print(
1234 " [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
1235 "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1236 "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
1237 EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
1238 EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1239 EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1240 EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1241 EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1242 EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1243 EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1244 EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1245 EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1246 EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1247 EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1249 if (full) {
1250 MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1251 }
1253 gclog_or_tty->cr();
1254 }
1256 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1257 double update_rs_processed_buffers,
1258 double goal_ms) {
1259 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1260 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1262 if (G1UseAdaptiveConcRefinement) {
1263 const int k_gy = 3, k_gr = 6;
1264 const double inc_k = 1.1, dec_k = 0.9;
1266 int g = cg1r->green_zone();
1267 if (update_rs_time > goal_ms) {
1268 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1269 } else {
1270 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1271 g = (int)MAX2(g * inc_k, g + 1.0);
1272 }
1273 }
1274 // Change the refinement threads params
1275 cg1r->set_green_zone(g);
1276 cg1r->set_yellow_zone(g * k_gy);
1277 cg1r->set_red_zone(g * k_gr);
1278 cg1r->reinitialize_threads();
1280 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1281 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1282 cg1r->yellow_zone());
1283 // Change the barrier params
1284 dcqs.set_process_completed_threshold(processing_threshold);
1285 dcqs.set_max_completed_queue(cg1r->red_zone());
1286 }
1288 int curr_queue_size = dcqs.completed_buffers_num();
1289 if (curr_queue_size >= cg1r->yellow_zone()) {
1290 dcqs.set_completed_queue_padding(curr_queue_size);
1291 } else {
1292 dcqs.set_completed_queue_padding(0);
1293 }
1294 dcqs.notify_if_necessary();
1295 }
1297 double
1298 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1299 size_t scanned_cards) {
1300 return
1301 predict_rs_update_time_ms(pending_cards) +
1302 predict_rs_scan_time_ms(scanned_cards) +
1303 predict_constant_other_time_ms();
1304 }
1306 double
1307 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1308 size_t rs_length = predict_rs_length_diff();
1309 size_t card_num;
1310 if (gcs_are_young()) {
1311 card_num = predict_young_card_num(rs_length);
1312 } else {
1313 card_num = predict_non_young_card_num(rs_length);
1314 }
1315 return predict_base_elapsed_time_ms(pending_cards, card_num);
1316 }
1318 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1319 size_t bytes_to_copy;
1320 if (hr->is_marked())
1321 bytes_to_copy = hr->max_live_bytes();
1322 else {
1323 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1324 int age = hr->age_in_surv_rate_group();
1325 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1326 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1327 }
1328 return bytes_to_copy;
1329 }
1331 double
1332 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1333 bool for_young_gc) {
1334 size_t rs_length = hr->rem_set()->occupied();
1335 size_t card_num;
1337 // Predicting the number of cards is based on which type of GC
1338 // we're predicting for.
1339 if (for_young_gc) {
1340 card_num = predict_young_card_num(rs_length);
1341 } else {
1342 card_num = predict_non_young_card_num(rs_length);
1343 }
1344 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1346 double region_elapsed_time_ms =
1347 predict_rs_scan_time_ms(card_num) +
1348 predict_object_copy_time_ms(bytes_to_copy);
1350 // The prediction of the "other" time for this region is based
1351 // upon the region type and NOT the GC type.
1352 if (hr->is_young()) {
1353 region_elapsed_time_ms += predict_young_other_time_ms(1);
1354 } else {
1355 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1356 }
1357 return region_elapsed_time_ms;
1358 }
1360 void
1361 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1362 uint survivor_cset_region_length) {
1363 _eden_cset_region_length = eden_cset_region_length;
1364 _survivor_cset_region_length = survivor_cset_region_length;
1365 _old_cset_region_length = 0;
1366 }
1368 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1369 _recorded_rs_lengths = rs_lengths;
1370 }
1372 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1373 double elapsed_ms) {
1374 _recent_gc_times_ms->add(elapsed_ms);
1375 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1376 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1377 }
1379 size_t G1CollectorPolicy::expansion_amount() {
1380 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1381 double threshold = _gc_overhead_perc;
1382 if (recent_gc_overhead > threshold) {
1383 // We will double the existing space, or take
1384 // G1ExpandByPercentOfAvailable % of the available expansion
1385 // space, whichever is smaller, bounded below by a minimum
1386 // expansion (unless that's all that's left.)
1387 const size_t min_expand_bytes = 1*M;
1388 size_t reserved_bytes = _g1->max_capacity();
1389 size_t committed_bytes = _g1->capacity();
1390 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1391 size_t expand_bytes;
1392 size_t expand_bytes_via_pct =
1393 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1394 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1395 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1396 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1398 ergo_verbose5(ErgoHeapSizing,
1399 "attempt heap expansion",
1400 ergo_format_reason("recent GC overhead higher than "
1401 "threshold after GC")
1402 ergo_format_perc("recent GC overhead")
1403 ergo_format_perc("threshold")
1404 ergo_format_byte("uncommitted")
1405 ergo_format_byte_perc("calculated expansion amount"),
1406 recent_gc_overhead, threshold,
1407 uncommitted_bytes,
1408 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1410 return expand_bytes;
1411 } else {
1412 return 0;
1413 }
1414 }
1416 void G1CollectorPolicy::print_tracing_info() const {
1417 _trace_gen0_time_data.print();
1418 _trace_gen1_time_data.print();
1419 }
1421 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1422 #ifndef PRODUCT
1423 _short_lived_surv_rate_group->print_surv_rate_summary();
1424 // add this call for any other surv rate groups
1425 #endif // PRODUCT
1426 }
1428 bool G1CollectorPolicy::is_young_list_full() {
1429 uint young_list_length = _g1->young_list()->length();
1430 uint young_list_target_length = _young_list_target_length;
1431 return young_list_length >= young_list_target_length;
1432 }
1434 bool G1CollectorPolicy::can_expand_young_list() {
1435 uint young_list_length = _g1->young_list()->length();
1436 uint young_list_max_length = _young_list_max_length;
1437 return young_list_length < young_list_max_length;
1438 }
1440 uint G1CollectorPolicy::max_regions(int purpose) {
1441 switch (purpose) {
1442 case GCAllocForSurvived:
1443 return _max_survivor_regions;
1444 case GCAllocForTenured:
1445 return REGIONS_UNLIMITED;
1446 default:
1447 ShouldNotReachHere();
1448 return REGIONS_UNLIMITED;
1449 };
1450 }
1452 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1453 uint expansion_region_num = 0;
1454 if (GCLockerEdenExpansionPercent > 0) {
1455 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1456 double expansion_region_num_d = perc * (double) _young_list_target_length;
1457 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1458 // less than 1.0) we'll get 1.
1459 expansion_region_num = (uint) ceil(expansion_region_num_d);
1460 } else {
1461 assert(expansion_region_num == 0, "sanity");
1462 }
1463 _young_list_max_length = _young_list_target_length + expansion_region_num;
1464 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1465 }
1467 // Calculates survivor space parameters.
1468 void G1CollectorPolicy::update_survivors_policy() {
1469 double max_survivor_regions_d =
1470 (double) _young_list_target_length / (double) SurvivorRatio;
1471 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1472 // smaller than 1.0) we'll get 1.
1473 _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1475 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1476 HeapRegion::GrainWords * _max_survivor_regions);
1477 }
1479 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
1480 GCCause::Cause gc_cause) {
1481 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1482 if (!during_cycle) {
1483 ergo_verbose1(ErgoConcCycles,
1484 "request concurrent cycle initiation",
1485 ergo_format_reason("requested by GC cause")
1486 ergo_format_str("GC cause"),
1487 GCCause::to_string(gc_cause));
1488 set_initiate_conc_mark_if_possible();
1489 return true;
1490 } else {
1491 ergo_verbose1(ErgoConcCycles,
1492 "do not request concurrent cycle initiation",
1493 ergo_format_reason("concurrent cycle already in progress")
1494 ergo_format_str("GC cause"),
1495 GCCause::to_string(gc_cause));
1496 return false;
1497 }
1498 }
1500 void
1501 G1CollectorPolicy::decide_on_conc_mark_initiation() {
1502 // We are about to decide on whether this pause will be an
1503 // initial-mark pause.
1505 // First, during_initial_mark_pause() should not be already set. We
1506 // will set it here if we have to. However, it should be cleared by
1507 // the end of the pause (it's only set for the duration of an
1508 // initial-mark pause).
1509 assert(!during_initial_mark_pause(), "pre-condition");
1511 if (initiate_conc_mark_if_possible()) {
1512 // We had noticed on a previous pause that the heap occupancy has
1513 // gone over the initiating threshold and we should start a
1514 // concurrent marking cycle. So we might initiate one.
1516 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1517 if (!during_cycle) {
1518 // The concurrent marking thread is not "during a cycle", i.e.,
1519 // it has completed the last one. So we can go ahead and
1520 // initiate a new cycle.
1522 set_during_initial_mark_pause();
1523 // We do not allow mixed GCs during marking.
1524 if (!gcs_are_young()) {
1525 set_gcs_are_young(true);
1526 ergo_verbose0(ErgoMixedGCs,
1527 "end mixed GCs",
1528 ergo_format_reason("concurrent cycle is about to start"));
1529 }
1531 // And we can now clear initiate_conc_mark_if_possible() as
1532 // we've already acted on it.
1533 clear_initiate_conc_mark_if_possible();
1535 ergo_verbose0(ErgoConcCycles,
1536 "initiate concurrent cycle",
1537 ergo_format_reason("concurrent cycle initiation requested"));
1538 } else {
1539 // The concurrent marking thread is still finishing up the
1540 // previous cycle. If we start one right now the two cycles
1541 // overlap. In particular, the concurrent marking thread might
1542 // be in the process of clearing the next marking bitmap (which
1543 // we will use for the next cycle if we start one). Starting a
1544 // cycle now will be bad given that parts of the marking
1545 // information might get cleared by the marking thread. And we
1546 // cannot wait for the marking thread to finish the cycle as it
1547 // periodically yields while clearing the next marking bitmap
1548 // and, if it's in a yield point, it's waiting for us to
1549 // finish. So, at this point we will not start a cycle and we'll
1550 // let the concurrent marking thread complete the last one.
1551 ergo_verbose0(ErgoConcCycles,
1552 "do not initiate concurrent cycle",
1553 ergo_format_reason("concurrent cycle already in progress"));
1554 }
1555 }
1556 }
1558 class KnownGarbageClosure: public HeapRegionClosure {
1559 G1CollectedHeap* _g1h;
1560 CollectionSetChooser* _hrSorted;
1562 public:
1563 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
1564 _g1h(G1CollectedHeap::heap()), _hrSorted(hrSorted) { }
1566 bool doHeapRegion(HeapRegion* r) {
1567 // We only include humongous regions in collection
1568 // sets when concurrent mark shows that their contained object is
1569 // unreachable.
1571 // Do we have any marking information for this region?
1572 if (r->is_marked()) {
1573 // We will skip any region that's currently used as an old GC
1574 // alloc region (we should not consider those for collection
1575 // before we fill them up).
1576 if (_hrSorted->should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1577 _hrSorted->add_region(r);
1578 }
1579 }
1580 return false;
1581 }
1582 };
1584 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1585 G1CollectedHeap* _g1h;
1586 CSetChooserParUpdater _cset_updater;
1588 public:
1589 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1590 uint chunk_size) :
1591 _g1h(G1CollectedHeap::heap()),
1592 _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1594 bool doHeapRegion(HeapRegion* r) {
1595 // Do we have any marking information for this region?
1596 if (r->is_marked()) {
1597 // We will skip any region that's currently used as an old GC
1598 // alloc region (we should not consider those for collection
1599 // before we fill them up).
1600 if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1601 _cset_updater.add_region(r);
1602 }
1603 }
1604 return false;
1605 }
1606 };
1608 class ParKnownGarbageTask: public AbstractGangTask {
1609 CollectionSetChooser* _hrSorted;
1610 uint _chunk_size;
1611 G1CollectedHeap* _g1;
1612 public:
1613 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size) :
1614 AbstractGangTask("ParKnownGarbageTask"),
1615 _hrSorted(hrSorted), _chunk_size(chunk_size),
1616 _g1(G1CollectedHeap::heap()) { }
1618 void work(uint worker_id) {
1619 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1621 // Back to zero for the claim value.
1622 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, worker_id,
1623 _g1->workers()->active_workers(),
1624 HeapRegion::InitialClaimValue);
1625 }
1626 };
1628 void
1629 G1CollectorPolicy::record_concurrent_mark_cleanup_end(int no_of_gc_threads) {
1630 _collectionSetChooser->clear();
1632 uint region_num = _g1->num_regions();
1633 if (G1CollectedHeap::use_parallel_gc_threads()) {
1634 const uint OverpartitionFactor = 4;
1635 uint WorkUnit;
1636 // The use of MinChunkSize = 8 in the original code
1637 // causes some assertion failures when the total number of
1638 // region is less than 8. The code here tries to fix that.
1639 // Should the original code also be fixed?
1640 if (no_of_gc_threads > 0) {
1641 const uint MinWorkUnit = MAX2(region_num / no_of_gc_threads, 1U);
1642 WorkUnit = MAX2(region_num / (no_of_gc_threads * OverpartitionFactor),
1643 MinWorkUnit);
1644 } else {
1645 assert(no_of_gc_threads > 0,
1646 "The active gc workers should be greater than 0");
1647 // In a product build do something reasonable to avoid a crash.
1648 const uint MinWorkUnit = MAX2(region_num / (uint) ParallelGCThreads, 1U);
1649 WorkUnit =
1650 MAX2(region_num / (uint) (ParallelGCThreads * OverpartitionFactor),
1651 MinWorkUnit);
1652 }
1653 _collectionSetChooser->prepare_for_par_region_addition(_g1->num_regions(),
1654 WorkUnit);
1655 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
1656 (int) WorkUnit);
1657 _g1->workers()->run_task(&parKnownGarbageTask);
1659 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
1660 "sanity check");
1661 } else {
1662 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
1663 _g1->heap_region_iterate(&knownGarbagecl);
1664 }
1666 _collectionSetChooser->sort_regions();
1668 double end_sec = os::elapsedTime();
1669 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1670 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1671 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1672 _prev_collection_pause_end_ms += elapsed_time_ms;
1673 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true);
1674 }
1676 // Add the heap region at the head of the non-incremental collection set
1677 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1678 assert(_inc_cset_build_state == Active, "Precondition");
1679 assert(hr->is_old(), "the region should be old");
1681 assert(!hr->in_collection_set(), "should not already be in the CSet");
1682 hr->set_in_collection_set(true);
1683 hr->set_next_in_collection_set(_collection_set);
1684 _collection_set = hr;
1685 _collection_set_bytes_used_before += hr->used();
1686 _g1->register_region_with_in_cset_fast_test(hr);
1687 size_t rs_length = hr->rem_set()->occupied();
1688 _recorded_rs_lengths += rs_length;
1689 _old_cset_region_length += 1;
1690 }
1692 // Initialize the per-collection-set information
1693 void G1CollectorPolicy::start_incremental_cset_building() {
1694 assert(_inc_cset_build_state == Inactive, "Precondition");
1696 _inc_cset_head = NULL;
1697 _inc_cset_tail = NULL;
1698 _inc_cset_bytes_used_before = 0;
1700 _inc_cset_max_finger = 0;
1701 _inc_cset_recorded_rs_lengths = 0;
1702 _inc_cset_recorded_rs_lengths_diffs = 0;
1703 _inc_cset_predicted_elapsed_time_ms = 0.0;
1704 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1705 _inc_cset_build_state = Active;
1706 }
1708 void G1CollectorPolicy::finalize_incremental_cset_building() {
1709 assert(_inc_cset_build_state == Active, "Precondition");
1710 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1712 // The two "main" fields, _inc_cset_recorded_rs_lengths and
1713 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1714 // that adds a new region to the CSet. Further updates by the
1715 // concurrent refinement thread that samples the young RSet lengths
1716 // are accumulated in the *_diffs fields. Here we add the diffs to
1717 // the "main" fields.
1719 if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1720 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1721 } else {
1722 // This is defensive. The diff should in theory be always positive
1723 // as RSets can only grow between GCs. However, given that we
1724 // sample their size concurrently with other threads updating them
1725 // it's possible that we might get the wrong size back, which
1726 // could make the calculations somewhat inaccurate.
1727 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1728 if (_inc_cset_recorded_rs_lengths >= diffs) {
1729 _inc_cset_recorded_rs_lengths -= diffs;
1730 } else {
1731 _inc_cset_recorded_rs_lengths = 0;
1732 }
1733 }
1734 _inc_cset_predicted_elapsed_time_ms +=
1735 _inc_cset_predicted_elapsed_time_ms_diffs;
1737 _inc_cset_recorded_rs_lengths_diffs = 0;
1738 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1739 }
1741 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1742 // This routine is used when:
1743 // * adding survivor regions to the incremental cset at the end of an
1744 // evacuation pause,
1745 // * adding the current allocation region to the incremental cset
1746 // when it is retired, and
1747 // * updating existing policy information for a region in the
1748 // incremental cset via young list RSet sampling.
1749 // Therefore this routine may be called at a safepoint by the
1750 // VM thread, or in-between safepoints by mutator threads (when
1751 // retiring the current allocation region) or a concurrent
1752 // refine thread (RSet sampling).
1754 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1755 size_t used_bytes = hr->used();
1756 _inc_cset_recorded_rs_lengths += rs_length;
1757 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1758 _inc_cset_bytes_used_before += used_bytes;
1760 // Cache the values we have added to the aggregated informtion
1761 // in the heap region in case we have to remove this region from
1762 // the incremental collection set, or it is updated by the
1763 // rset sampling code
1764 hr->set_recorded_rs_length(rs_length);
1765 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1766 }
1768 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1769 size_t new_rs_length) {
1770 // Update the CSet information that is dependent on the new RS length
1771 assert(hr->is_young(), "Precondition");
1772 assert(!SafepointSynchronize::is_at_safepoint(),
1773 "should not be at a safepoint");
1775 // We could have updated _inc_cset_recorded_rs_lengths and
1776 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1777 // that atomically, as this code is executed by a concurrent
1778 // refinement thread, potentially concurrently with a mutator thread
1779 // allocating a new region and also updating the same fields. To
1780 // avoid the atomic operations we accumulate these updates on two
1781 // separate fields (*_diffs) and we'll just add them to the "main"
1782 // fields at the start of a GC.
1784 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1785 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1786 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1788 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1789 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1790 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1791 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1793 hr->set_recorded_rs_length(new_rs_length);
1794 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1795 }
1797 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1798 assert(hr->is_young(), "invariant");
1799 assert(hr->young_index_in_cset() > -1, "should have already been set");
1800 assert(_inc_cset_build_state == Active, "Precondition");
1802 // We need to clear and set the cached recorded/cached collection set
1803 // information in the heap region here (before the region gets added
1804 // to the collection set). An individual heap region's cached values
1805 // are calculated, aggregated with the policy collection set info,
1806 // and cached in the heap region here (initially) and (subsequently)
1807 // by the Young List sampling code.
1809 size_t rs_length = hr->rem_set()->occupied();
1810 add_to_incremental_cset_info(hr, rs_length);
1812 HeapWord* hr_end = hr->end();
1813 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1815 assert(!hr->in_collection_set(), "invariant");
1816 hr->set_in_collection_set(true);
1817 assert( hr->next_in_collection_set() == NULL, "invariant");
1819 _g1->register_region_with_in_cset_fast_test(hr);
1820 }
1822 // Add the region at the RHS of the incremental cset
1823 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1824 // We should only ever be appending survivors at the end of a pause
1825 assert(hr->is_survivor(), "Logic");
1827 // Do the 'common' stuff
1828 add_region_to_incremental_cset_common(hr);
1830 // Now add the region at the right hand side
1831 if (_inc_cset_tail == NULL) {
1832 assert(_inc_cset_head == NULL, "invariant");
1833 _inc_cset_head = hr;
1834 } else {
1835 _inc_cset_tail->set_next_in_collection_set(hr);
1836 }
1837 _inc_cset_tail = hr;
1838 }
1840 // Add the region to the LHS of the incremental cset
1841 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1842 // Survivors should be added to the RHS at the end of a pause
1843 assert(hr->is_eden(), "Logic");
1845 // Do the 'common' stuff
1846 add_region_to_incremental_cset_common(hr);
1848 // Add the region at the left hand side
1849 hr->set_next_in_collection_set(_inc_cset_head);
1850 if (_inc_cset_head == NULL) {
1851 assert(_inc_cset_tail == NULL, "Invariant");
1852 _inc_cset_tail = hr;
1853 }
1854 _inc_cset_head = hr;
1855 }
1857 #ifndef PRODUCT
1858 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1859 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1861 st->print_cr("\nCollection_set:");
1862 HeapRegion* csr = list_head;
1863 while (csr != NULL) {
1864 HeapRegion* next = csr->next_in_collection_set();
1865 assert(csr->in_collection_set(), "bad CS");
1866 st->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
1867 HR_FORMAT_PARAMS(csr),
1868 csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(),
1869 csr->age_in_surv_rate_group_cond());
1870 csr = next;
1871 }
1872 }
1873 #endif // !PRODUCT
1875 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) {
1876 // Returns the given amount of reclaimable bytes (that represents
1877 // the amount of reclaimable space still to be collected) as a
1878 // percentage of the current heap capacity.
1879 size_t capacity_bytes = _g1->capacity();
1880 return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1881 }
1883 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1884 const char* false_action_str) {
1885 CollectionSetChooser* cset_chooser = _collectionSetChooser;
1886 if (cset_chooser->is_empty()) {
1887 ergo_verbose0(ErgoMixedGCs,
1888 false_action_str,
1889 ergo_format_reason("candidate old regions not available"));
1890 return false;
1891 }
1893 // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1894 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1895 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1896 double threshold = (double) G1HeapWastePercent;
1897 if (reclaimable_perc <= threshold) {
1898 ergo_verbose4(ErgoMixedGCs,
1899 false_action_str,
1900 ergo_format_reason("reclaimable percentage not over threshold")
1901 ergo_format_region("candidate old regions")
1902 ergo_format_byte_perc("reclaimable")
1903 ergo_format_perc("threshold"),
1904 cset_chooser->remaining_regions(),
1905 reclaimable_bytes,
1906 reclaimable_perc, threshold);
1907 return false;
1908 }
1910 ergo_verbose4(ErgoMixedGCs,
1911 true_action_str,
1912 ergo_format_reason("candidate old regions available")
1913 ergo_format_region("candidate old regions")
1914 ergo_format_byte_perc("reclaimable")
1915 ergo_format_perc("threshold"),
1916 cset_chooser->remaining_regions(),
1917 reclaimable_bytes,
1918 reclaimable_perc, threshold);
1919 return true;
1920 }
1922 uint G1CollectorPolicy::calc_min_old_cset_length() {
1923 // The min old CSet region bound is based on the maximum desired
1924 // number of mixed GCs after a cycle. I.e., even if some old regions
1925 // look expensive, we should add them to the CSet anyway to make
1926 // sure we go through the available old regions in no more than the
1927 // maximum desired number of mixed GCs.
1928 //
1929 // The calculation is based on the number of marked regions we added
1930 // to the CSet chooser in the first place, not how many remain, so
1931 // that the result is the same during all mixed GCs that follow a cycle.
1933 const size_t region_num = (size_t) _collectionSetChooser->length();
1934 const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
1935 size_t result = region_num / gc_num;
1936 // emulate ceiling
1937 if (result * gc_num < region_num) {
1938 result += 1;
1939 }
1940 return (uint) result;
1941 }
1943 uint G1CollectorPolicy::calc_max_old_cset_length() {
1944 // The max old CSet region bound is based on the threshold expressed
1945 // as a percentage of the heap size. I.e., it should bound the
1946 // number of old regions added to the CSet irrespective of how many
1947 // of them are available.
1949 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1950 const size_t region_num = g1h->num_regions();
1951 const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
1952 size_t result = region_num * perc / 100;
1953 // emulate ceiling
1954 if (100 * result < region_num * perc) {
1955 result += 1;
1956 }
1957 return (uint) result;
1958 }
1961 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info) {
1962 double young_start_time_sec = os::elapsedTime();
1964 YoungList* young_list = _g1->young_list();
1965 finalize_incremental_cset_building();
1967 guarantee(target_pause_time_ms > 0.0,
1968 err_msg("target_pause_time_ms = %1.6lf should be positive",
1969 target_pause_time_ms));
1970 guarantee(_collection_set == NULL, "Precondition");
1972 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
1973 double predicted_pause_time_ms = base_time_ms;
1974 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
1976 ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
1977 "start choosing CSet",
1978 ergo_format_size("_pending_cards")
1979 ergo_format_ms("predicted base time")
1980 ergo_format_ms("remaining time")
1981 ergo_format_ms("target pause time"),
1982 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
1984 _last_gc_was_young = gcs_are_young() ? true : false;
1986 if (_last_gc_was_young) {
1987 _trace_gen0_time_data.increment_young_collection_count();
1988 } else {
1989 _trace_gen0_time_data.increment_mixed_collection_count();
1990 }
1992 // The young list is laid with the survivor regions from the previous
1993 // pause are appended to the RHS of the young list, i.e.
1994 // [Newly Young Regions ++ Survivors from last pause].
1996 uint survivor_region_length = young_list->survivor_length();
1997 uint eden_region_length = young_list->length() - survivor_region_length;
1998 init_cset_region_lengths(eden_region_length, survivor_region_length);
2000 HeapRegion* hr = young_list->first_survivor_region();
2001 while (hr != NULL) {
2002 assert(hr->is_survivor(), "badly formed young list");
2003 // There is a convention that all the young regions in the CSet
2004 // are tagged as "eden", so we do this for the survivors here. We
2005 // use the special set_eden_pre_gc() as it doesn't check that the
2006 // region is free (which is not the case here).
2007 hr->set_eden_pre_gc();
2008 hr = hr->get_next_young_region();
2009 }
2011 // Clear the fields that point to the survivor list - they are all young now.
2012 young_list->clear_survivors();
2014 _collection_set = _inc_cset_head;
2015 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2016 time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
2017 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
2019 ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
2020 "add young regions to CSet",
2021 ergo_format_region("eden")
2022 ergo_format_region("survivors")
2023 ergo_format_ms("predicted young region time"),
2024 eden_region_length, survivor_region_length,
2025 _inc_cset_predicted_elapsed_time_ms);
2027 // The number of recorded young regions is the incremental
2028 // collection set's current size
2029 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2031 double young_end_time_sec = os::elapsedTime();
2032 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
2034 // Set the start of the non-young choice time.
2035 double non_young_start_time_sec = young_end_time_sec;
2037 if (!gcs_are_young()) {
2038 CollectionSetChooser* cset_chooser = _collectionSetChooser;
2039 cset_chooser->verify();
2040 const uint min_old_cset_length = calc_min_old_cset_length();
2041 const uint max_old_cset_length = calc_max_old_cset_length();
2043 uint expensive_region_num = 0;
2044 bool check_time_remaining = adaptive_young_list_length();
2046 HeapRegion* hr = cset_chooser->peek();
2047 while (hr != NULL) {
2048 if (old_cset_region_length() >= max_old_cset_length) {
2049 // Added maximum number of old regions to the CSet.
2050 ergo_verbose2(ErgoCSetConstruction,
2051 "finish adding old regions to CSet",
2052 ergo_format_reason("old CSet region num reached max")
2053 ergo_format_region("old")
2054 ergo_format_region("max"),
2055 old_cset_region_length(), max_old_cset_length);
2056 break;
2057 }
2060 // Stop adding regions if the remaining reclaimable space is
2061 // not above G1HeapWastePercent.
2062 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
2063 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
2064 double threshold = (double) G1HeapWastePercent;
2065 if (reclaimable_perc <= threshold) {
2066 // We've added enough old regions that the amount of uncollected
2067 // reclaimable space is at or below the waste threshold. Stop
2068 // adding old regions to the CSet.
2069 ergo_verbose5(ErgoCSetConstruction,
2070 "finish adding old regions to CSet",
2071 ergo_format_reason("reclaimable percentage not over threshold")
2072 ergo_format_region("old")
2073 ergo_format_region("max")
2074 ergo_format_byte_perc("reclaimable")
2075 ergo_format_perc("threshold"),
2076 old_cset_region_length(),
2077 max_old_cset_length,
2078 reclaimable_bytes,
2079 reclaimable_perc, threshold);
2080 break;
2081 }
2083 double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
2084 if (check_time_remaining) {
2085 if (predicted_time_ms > time_remaining_ms) {
2086 // Too expensive for the current CSet.
2088 if (old_cset_region_length() >= min_old_cset_length) {
2089 // We have added the minimum number of old regions to the CSet,
2090 // we are done with this CSet.
2091 ergo_verbose4(ErgoCSetConstruction,
2092 "finish adding old regions to CSet",
2093 ergo_format_reason("predicted time is too high")
2094 ergo_format_ms("predicted time")
2095 ergo_format_ms("remaining time")
2096 ergo_format_region("old")
2097 ergo_format_region("min"),
2098 predicted_time_ms, time_remaining_ms,
2099 old_cset_region_length(), min_old_cset_length);
2100 break;
2101 }
2103 // We'll add it anyway given that we haven't reached the
2104 // minimum number of old regions.
2105 expensive_region_num += 1;
2106 }
2107 } else {
2108 if (old_cset_region_length() >= min_old_cset_length) {
2109 // In the non-auto-tuning case, we'll finish adding regions
2110 // to the CSet if we reach the minimum.
2111 ergo_verbose2(ErgoCSetConstruction,
2112 "finish adding old regions to CSet",
2113 ergo_format_reason("old CSet region num reached min")
2114 ergo_format_region("old")
2115 ergo_format_region("min"),
2116 old_cset_region_length(), min_old_cset_length);
2117 break;
2118 }
2119 }
2121 // We will add this region to the CSet.
2122 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2123 predicted_pause_time_ms += predicted_time_ms;
2124 cset_chooser->remove_and_move_to_next(hr);
2125 _g1->old_set_remove(hr);
2126 add_old_region_to_cset(hr);
2128 hr = cset_chooser->peek();
2129 }
2130 if (hr == NULL) {
2131 ergo_verbose0(ErgoCSetConstruction,
2132 "finish adding old regions to CSet",
2133 ergo_format_reason("candidate old regions not available"));
2134 }
2136 if (expensive_region_num > 0) {
2137 // We print the information once here at the end, predicated on
2138 // whether we added any apparently expensive regions or not, to
2139 // avoid generating output per region.
2140 ergo_verbose4(ErgoCSetConstruction,
2141 "added expensive regions to CSet",
2142 ergo_format_reason("old CSet region num not reached min")
2143 ergo_format_region("old")
2144 ergo_format_region("expensive")
2145 ergo_format_region("min")
2146 ergo_format_ms("remaining time"),
2147 old_cset_region_length(),
2148 expensive_region_num,
2149 min_old_cset_length,
2150 time_remaining_ms);
2151 }
2153 cset_chooser->verify();
2154 }
2156 stop_incremental_cset_building();
2158 ergo_verbose5(ErgoCSetConstruction,
2159 "finish choosing CSet",
2160 ergo_format_region("eden")
2161 ergo_format_region("survivors")
2162 ergo_format_region("old")
2163 ergo_format_ms("predicted pause time")
2164 ergo_format_ms("target pause time"),
2165 eden_region_length, survivor_region_length,
2166 old_cset_region_length(),
2167 predicted_pause_time_ms, target_pause_time_ms);
2169 double non_young_end_time_sec = os::elapsedTime();
2170 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2171 evacuation_info.set_collectionset_regions(cset_region_length());
2172 }
2174 void TraceGen0TimeData::record_start_collection(double time_to_stop_the_world_ms) {
2175 if(TraceGen0Time) {
2176 _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2177 }
2178 }
2180 void TraceGen0TimeData::record_yield_time(double yield_time_ms) {
2181 if(TraceGen0Time) {
2182 _all_yield_times_ms.add(yield_time_ms);
2183 }
2184 }
2186 void TraceGen0TimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2187 if(TraceGen0Time) {
2188 _total.add(pause_time_ms);
2189 _other.add(pause_time_ms - phase_times->accounted_time_ms());
2190 _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2191 _parallel.add(phase_times->cur_collection_par_time_ms());
2192 _ext_root_scan.add(phase_times->average_last_ext_root_scan_time());
2193 _satb_filtering.add(phase_times->average_last_satb_filtering_times_ms());
2194 _update_rs.add(phase_times->average_last_update_rs_time());
2195 _scan_rs.add(phase_times->average_last_scan_rs_time());
2196 _obj_copy.add(phase_times->average_last_obj_copy_time());
2197 _termination.add(phase_times->average_last_termination_time());
2199 double parallel_known_time = phase_times->average_last_ext_root_scan_time() +
2200 phase_times->average_last_satb_filtering_times_ms() +
2201 phase_times->average_last_update_rs_time() +
2202 phase_times->average_last_scan_rs_time() +
2203 phase_times->average_last_obj_copy_time() +
2204 + phase_times->average_last_termination_time();
2206 double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2207 _parallel_other.add(parallel_other_time);
2208 _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2209 }
2210 }
2212 void TraceGen0TimeData::increment_young_collection_count() {
2213 if(TraceGen0Time) {
2214 ++_young_pause_num;
2215 }
2216 }
2218 void TraceGen0TimeData::increment_mixed_collection_count() {
2219 if(TraceGen0Time) {
2220 ++_mixed_pause_num;
2221 }
2222 }
2224 void TraceGen0TimeData::print_summary(const char* str,
2225 const NumberSeq* seq) const {
2226 double sum = seq->sum();
2227 gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2228 str, sum / 1000.0, seq->avg());
2229 }
2231 void TraceGen0TimeData::print_summary_sd(const char* str,
2232 const NumberSeq* seq) const {
2233 print_summary(str, seq);
2234 gclog_or_tty->print_cr("%+45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2235 "(num", seq->num(), seq->sd(), seq->maximum());
2236 }
2238 void TraceGen0TimeData::print() const {
2239 if (!TraceGen0Time) {
2240 return;
2241 }
2243 gclog_or_tty->print_cr("ALL PAUSES");
2244 print_summary_sd(" Total", &_total);
2245 gclog_or_tty->cr();
2246 gclog_or_tty->cr();
2247 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num);
2248 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num);
2249 gclog_or_tty->cr();
2251 gclog_or_tty->print_cr("EVACUATION PAUSES");
2253 if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2254 gclog_or_tty->print_cr("none");
2255 } else {
2256 print_summary_sd(" Evacuation Pauses", &_total);
2257 print_summary(" Root Region Scan Wait", &_root_region_scan_wait);
2258 print_summary(" Parallel Time", &_parallel);
2259 print_summary(" Ext Root Scanning", &_ext_root_scan);
2260 print_summary(" SATB Filtering", &_satb_filtering);
2261 print_summary(" Update RS", &_update_rs);
2262 print_summary(" Scan RS", &_scan_rs);
2263 print_summary(" Object Copy", &_obj_copy);
2264 print_summary(" Termination", &_termination);
2265 print_summary(" Parallel Other", &_parallel_other);
2266 print_summary(" Clear CT", &_clear_ct);
2267 print_summary(" Other", &_other);
2268 }
2269 gclog_or_tty->cr();
2271 gclog_or_tty->print_cr("MISC");
2272 print_summary_sd(" Stop World", &_all_stop_world_times_ms);
2273 print_summary_sd(" Yields", &_all_yield_times_ms);
2274 }
2276 void TraceGen1TimeData::record_full_collection(double full_gc_time_ms) {
2277 if (TraceGen1Time) {
2278 _all_full_gc_times.add(full_gc_time_ms);
2279 }
2280 }
2282 void TraceGen1TimeData::print() const {
2283 if (!TraceGen1Time) {
2284 return;
2285 }
2287 if (_all_full_gc_times.num() > 0) {
2288 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2289 _all_full_gc_times.num(),
2290 _all_full_gc_times.sum() / 1000.0);
2291 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2292 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2293 _all_full_gc_times.sd(),
2294 _all_full_gc_times.maximum());
2295 }
2296 }