1 /*
2 * Copyright (c) 2001, 2015, 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.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/concurrentG1Refine.hpp"
27 #include "gc/g1/concurrentMark.hpp"
28 #include "gc/g1/concurrentMarkThread.inline.hpp"
29 #include "gc/g1/g1CollectedHeap.inline.hpp"
30 #include "gc/g1/g1CollectorPolicy.hpp"
31 #include "gc/g1/g1ErgoVerbose.hpp"
32 #include "gc/g1/g1GCPhaseTimes.hpp"
33 #include "gc/g1/g1Log.hpp"
34 #include "gc/g1/heapRegion.inline.hpp"
35 #include "gc/g1/heapRegionRemSet.hpp"
36 #include "gc/shared/gcPolicyCounters.hpp"
37 #include "runtime/arguments.hpp"
38 #include "runtime/java.hpp"
39 #include "runtime/mutexLocker.hpp"
40 #include "utilities/debug.hpp"
41
42 // Different defaults for different number of GC threads
43 // They were chosen by running GCOld and SPECjbb on debris with different
44 // numbers of GC threads and choosing them based on the results
45
46 // all the same
47 static double rs_length_diff_defaults[] = {
48 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
49 };
50
51 static double cost_per_card_ms_defaults[] = {
52 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
53 };
54
55 // all the same
56 static double young_cards_per_entry_ratio_defaults[] = {
57 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
58 };
59
60 static double cost_per_entry_ms_defaults[] = {
61 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
62 };
63
64 static double cost_per_byte_ms_defaults[] = {
65 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
66 };
67
68 // these should be pretty consistent
69 static double constant_other_time_ms_defaults[] = {
70 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
71 };
72
73
74 static double young_other_cost_per_region_ms_defaults[] = {
75 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
76 };
77
78 static double non_young_other_cost_per_region_ms_defaults[] = {
79 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
80 };
81
82 G1CollectorPolicy::G1CollectorPolicy() :
83 _parallel_gc_threads(ParallelGCThreads),
84
85 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
86 _stop_world_start(0.0),
87
88 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
89 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
90
91 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
92 _prev_collection_pause_end_ms(0.0),
93 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
94 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
95 _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
96 _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
97 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
98 _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
99 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
100 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
101 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
102 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
103 _non_young_other_cost_per_region_ms_seq(
104 new TruncatedSeq(TruncatedSeqLength)),
105
106 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
107 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
108
109 _pause_time_target_ms((double) MaxGCPauseMillis),
110
111 _recent_prev_end_times_for_all_gcs_sec(
112 new TruncatedSeq(NumPrevPausesForHeuristics)),
113
114 _recent_avg_pause_time_ratio(0.0),
115
116 _eden_used_bytes_before_gc(0),
117 _survivor_used_bytes_before_gc(0),
118 _heap_used_bytes_before_gc(0),
119 _metaspace_used_bytes_before_gc(0),
120 _eden_capacity_bytes_before_gc(0),
121 _heap_capacity_bytes_before_gc(0),
122
123 _eden_cset_region_length(0),
124 _survivor_cset_region_length(0),
125 _old_cset_region_length(0),
126
127 _sigma(G1ConfidencePercent / 100.0),
128
129 _collection_set(NULL),
130 _collection_set_bytes_used_before(0),
131
132 // Incremental CSet attributes
133 _inc_cset_build_state(Inactive),
134 _inc_cset_head(NULL),
135 _inc_cset_tail(NULL),
136 _inc_cset_bytes_used_before(0),
137 _inc_cset_max_finger(NULL),
138 _inc_cset_recorded_rs_lengths(0),
139 _inc_cset_recorded_rs_lengths_diffs(0),
140 _inc_cset_predicted_elapsed_time_ms(0.0),
141 _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
142
143 // add here any more surv rate groups
144 _recorded_survivor_regions(0),
145 _recorded_survivor_head(NULL),
146 _recorded_survivor_tail(NULL),
147 _survivors_age_table(true),
148
149 _gc_overhead_perc(0.0) {
150
151 // SurvRateGroups below must be initialized after '_sigma' because they
152 // indirectly access '_sigma' through this object passed to their constructor.
153 _short_lived_surv_rate_group =
154 new SurvRateGroup(this, "Short Lived", G1YoungSurvRateNumRegionsSummary);
155 _survivor_surv_rate_group =
156 new SurvRateGroup(this, "Survivor", G1YoungSurvRateNumRegionsSummary);
157
158 // Set up the region size and associated fields. Given that the
159 // policy is created before the heap, we have to set this up here,
160 // so it's done as soon as possible.
161
162 // It would have been natural to pass initial_heap_byte_size() and
163 // max_heap_byte_size() to setup_heap_region_size() but those have
164 // not been set up at this point since they should be aligned with
165 // the region size. So, there is a circular dependency here. We base
166 // the region size on the heap size, but the heap size should be
167 // aligned with the region size. To get around this we use the
168 // unaligned values for the heap.
169 HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
170 HeapRegionRemSet::setup_remset_size();
171
172 G1ErgoVerbose::initialize();
173 if (PrintAdaptiveSizePolicy) {
174 // Currently, we only use a single switch for all the heuristics.
175 G1ErgoVerbose::set_enabled(true);
176 // Given that we don't currently have a verboseness level
177 // parameter, we'll hardcode this to high. This can be easily
178 // changed in the future.
179 G1ErgoVerbose::set_level(ErgoHigh);
180 } else {
181 G1ErgoVerbose::set_enabled(false);
182 }
183
184 // Verify PLAB sizes
185 const size_t region_size = HeapRegion::GrainWords;
186 if (YoungPLABSize > region_size || OldPLABSize > region_size) {
187 char buffer[128];
188 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most " SIZE_FORMAT,
189 OldPLABSize > region_size ? "Old" : "Young", region_size);
190 vm_exit_during_initialization(buffer);
191 }
192
193 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
194 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
195
196 _phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
197
198 int index = MIN2(_parallel_gc_threads - 1, 7);
199
200 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
201 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
202 _young_cards_per_entry_ratio_seq->add(
203 young_cards_per_entry_ratio_defaults[index]);
204 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
205 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
206 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
207 _young_other_cost_per_region_ms_seq->add(
208 young_other_cost_per_region_ms_defaults[index]);
209 _non_young_other_cost_per_region_ms_seq->add(
210 non_young_other_cost_per_region_ms_defaults[index]);
211
212 // Below, we might need to calculate the pause time target based on
213 // the pause interval. When we do so we are going to give G1 maximum
214 // flexibility and allow it to do pauses when it needs to. So, we'll
215 // arrange that the pause interval to be pause time target + 1 to
216 // ensure that a) the pause time target is maximized with respect to
217 // the pause interval and b) we maintain the invariant that pause
218 // time target < pause interval. If the user does not want this
219 // maximum flexibility, they will have to set the pause interval
220 // explicitly.
221
222 // First make sure that, if either parameter is set, its value is
223 // reasonable.
224 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
225 if (MaxGCPauseMillis < 1) {
226 vm_exit_during_initialization("MaxGCPauseMillis should be "
227 "greater than 0");
228 }
229 }
230 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
231 if (GCPauseIntervalMillis < 1) {
232 vm_exit_during_initialization("GCPauseIntervalMillis should be "
233 "greater than 0");
234 }
235 }
236
237 // Then, if the pause time target parameter was not set, set it to
238 // the default value.
239 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
240 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
241 // The default pause time target in G1 is 200ms
242 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
243 } else {
244 // We do not allow the pause interval to be set without the
245 // pause time target
246 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
247 "without setting MaxGCPauseMillis");
248 }
249 }
250
251 // Then, if the interval parameter was not set, set it according to
252 // the pause time target (this will also deal with the case when the
253 // pause time target is the default value).
254 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
255 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
256 }
257
258 // Finally, make sure that the two parameters are consistent.
259 if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
260 char buffer[256];
261 jio_snprintf(buffer, 256,
262 "MaxGCPauseMillis (%u) should be less than "
263 "GCPauseIntervalMillis (%u)",
264 MaxGCPauseMillis, GCPauseIntervalMillis);
265 vm_exit_during_initialization(buffer);
266 }
267
268 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
269 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
270 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
271
272 // start conservatively (around 50ms is about right)
273 _concurrent_mark_remark_times_ms->add(0.05);
274 _concurrent_mark_cleanup_times_ms->add(0.20);
275 _tenuring_threshold = MaxTenuringThreshold;
276 // _max_survivor_regions will be calculated by
277 // update_young_list_target_length() during initialization.
278 _max_survivor_regions = 0;
279
280 assert(GCTimeRatio > 0,
281 "we should have set it to a default value set_g1_gc_flags() "
282 "if a user set it to 0");
283 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
284
285 uintx reserve_perc = G1ReservePercent;
286 // Put an artificial ceiling on this so that it's not set to a silly value.
287 if (reserve_perc > 50) {
288 reserve_perc = 50;
289 warning("G1ReservePercent is set to a value that is too large, "
290 "it's been updated to " UINTX_FORMAT, reserve_perc);
291 }
292 _reserve_factor = (double) reserve_perc / 100.0;
293 // This will be set when the heap is expanded
294 // for the first time during initialization.
295 _reserve_regions = 0;
296
297 _collectionSetChooser = new CollectionSetChooser();
298 }
299
300 void G1CollectorPolicy::initialize_alignments() {
301 _space_alignment = HeapRegion::GrainBytes;
302 size_t card_table_alignment = GenRemSet::max_alignment_constraint();
303 size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
304 _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
305 }
306
307 void G1CollectorPolicy::initialize_flags() {
308 if (G1HeapRegionSize != HeapRegion::GrainBytes) {
309 FLAG_SET_ERGO(size_t, G1HeapRegionSize, HeapRegion::GrainBytes);
310 }
311
312 if (SurvivorRatio < 1) {
313 vm_exit_during_initialization("Invalid survivor ratio specified");
314 }
315 CollectorPolicy::initialize_flags();
316 _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
317 }
318
319 void G1CollectorPolicy::post_heap_initialize() {
320 uintx max_regions = G1CollectedHeap::heap()->max_regions();
321 size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
322 if (max_young_size != MaxNewSize) {
323 FLAG_SET_ERGO(size_t, MaxNewSize, max_young_size);
324 }
325 }
326
327 G1CollectorState* G1CollectorPolicy::collector_state() { return _g1->collector_state(); }
328
329 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
330 _min_desired_young_length(0), _max_desired_young_length(0) {
331 if (FLAG_IS_CMDLINE(NewRatio)) {
332 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
333 warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
334 } else {
335 _sizer_kind = SizerNewRatio;
336 _adaptive_size = false;
337 return;
338 }
339 }
340
341 if (NewSize > MaxNewSize) {
342 if (FLAG_IS_CMDLINE(MaxNewSize)) {
343 warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
344 "A new max generation size of " SIZE_FORMAT "k will be used.",
345 NewSize/K, MaxNewSize/K, NewSize/K);
346 }
347 MaxNewSize = NewSize;
348 }
349
350 if (FLAG_IS_CMDLINE(NewSize)) {
351 _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
352 1U);
353 if (FLAG_IS_CMDLINE(MaxNewSize)) {
354 _max_desired_young_length =
355 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
356 1U);
357 _sizer_kind = SizerMaxAndNewSize;
358 _adaptive_size = _min_desired_young_length == _max_desired_young_length;
359 } else {
360 _sizer_kind = SizerNewSizeOnly;
361 }
362 } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
363 _max_desired_young_length =
364 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
365 1U);
366 _sizer_kind = SizerMaxNewSizeOnly;
367 }
368 }
369
370 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
371 uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
372 return MAX2(1U, default_value);
373 }
374
375 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
376 uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
377 return MAX2(1U, default_value);
378 }
379
380 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
381 assert(number_of_heap_regions > 0, "Heap must be initialized");
382
383 switch (_sizer_kind) {
384 case SizerDefaults:
385 *min_young_length = calculate_default_min_length(number_of_heap_regions);
386 *max_young_length = calculate_default_max_length(number_of_heap_regions);
387 break;
388 case SizerNewSizeOnly:
389 *max_young_length = calculate_default_max_length(number_of_heap_regions);
390 *max_young_length = MAX2(*min_young_length, *max_young_length);
391 break;
392 case SizerMaxNewSizeOnly:
393 *min_young_length = calculate_default_min_length(number_of_heap_regions);
394 *min_young_length = MIN2(*min_young_length, *max_young_length);
395 break;
396 case SizerMaxAndNewSize:
397 // Do nothing. Values set on the command line, don't update them at runtime.
398 break;
399 case SizerNewRatio:
400 *min_young_length = number_of_heap_regions / (NewRatio + 1);
401 *max_young_length = *min_young_length;
402 break;
403 default:
404 ShouldNotReachHere();
405 }
406
407 assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
408 }
409
410 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
411 // We need to pass the desired values because recalculation may not update these
412 // values in some cases.
413 uint temp = _min_desired_young_length;
414 uint result = _max_desired_young_length;
415 recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
416 return result;
417 }
418
419 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
420 recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
421 &_max_desired_young_length);
422 }
423
424 void G1CollectorPolicy::init() {
425 // Set aside an initial future to_space.
426 _g1 = G1CollectedHeap::heap();
427
428 assert(Heap_lock->owned_by_self(), "Locking discipline.");
429
430 initialize_gc_policy_counters();
431
432 if (adaptive_young_list_length()) {
433 _young_list_fixed_length = 0;
434 } else {
435 _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
436 }
437 _free_regions_at_end_of_collection = _g1->num_free_regions();
438 update_young_list_target_length();
439
440 // We may immediately start allocating regions and placing them on the
441 // collection set list. Initialize the per-collection set info
442 start_incremental_cset_building();
443 }
444
445 // Create the jstat counters for the policy.
446 void G1CollectorPolicy::initialize_gc_policy_counters() {
447 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
448 }
449
450 bool G1CollectorPolicy::predict_will_fit(uint young_length,
451 double base_time_ms,
452 uint base_free_regions,
453 double target_pause_time_ms) {
454 if (young_length >= base_free_regions) {
455 // end condition 1: not enough space for the young regions
456 return false;
457 }
458
459 double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
460 size_t bytes_to_copy =
461 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
462 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
463 double young_other_time_ms = predict_young_other_time_ms(young_length);
464 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
465 if (pause_time_ms > target_pause_time_ms) {
466 // end condition 2: prediction is over the target pause time
467 return false;
468 }
469
470 size_t free_bytes =
471 (base_free_regions - young_length) * HeapRegion::GrainBytes;
472 if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
473 // end condition 3: out-of-space (conservatively!)
474 return false;
475 }
476
477 // success!
478 return true;
479 }
480
481 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
482 // re-calculate the necessary reserve
483 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
484 // We use ceiling so that if reserve_regions_d is > 0.0 (but
485 // smaller than 1.0) we'll get 1.
486 _reserve_regions = (uint) ceil(reserve_regions_d);
487
488 _young_gen_sizer->heap_size_changed(new_number_of_regions);
489 }
490
491 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
492 uint base_min_length) {
493 uint desired_min_length = 0;
494 if (adaptive_young_list_length()) {
495 if (_alloc_rate_ms_seq->num() > 3) {
496 double now_sec = os::elapsedTime();
497 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
498 double alloc_rate_ms = predict_alloc_rate_ms();
499 desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
500 } else {
501 // otherwise we don't have enough info to make the prediction
502 }
503 }
504 desired_min_length += base_min_length;
505 // make sure we don't go below any user-defined minimum bound
506 return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
507 }
508
509 uint G1CollectorPolicy::calculate_young_list_desired_max_length() {
510 // Here, we might want to also take into account any additional
511 // constraints (i.e., user-defined minimum bound). Currently, we
512 // effectively don't set this bound.
513 return _young_gen_sizer->max_desired_young_length();
514 }
515
516 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
517 if (rs_lengths == (size_t) -1) {
518 // if it's set to the default value (-1), we should predict it;
519 // otherwise, use the given value.
520 rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
521 }
522
523 // Calculate the absolute and desired min bounds.
524
525 // This is how many young regions we already have (currently: the survivors).
526 uint base_min_length = recorded_survivor_regions();
527 uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
528 // This is the absolute minimum young length. Ensure that we
529 // will at least have one eden region available for allocation.
530 uint absolute_min_length = base_min_length + MAX2(_g1->young_list()->eden_length(), (uint)1);
531 // If we shrank the young list target it should not shrink below the current size.
532 desired_min_length = MAX2(desired_min_length, absolute_min_length);
533 // Calculate the absolute and desired max bounds.
534
535 // We will try our best not to "eat" into the reserve.
536 uint absolute_max_length = 0;
537 if (_free_regions_at_end_of_collection > _reserve_regions) {
538 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
539 }
540 uint desired_max_length = calculate_young_list_desired_max_length();
541 if (desired_max_length > absolute_max_length) {
542 desired_max_length = absolute_max_length;
543 }
544
545 uint young_list_target_length = 0;
546 if (adaptive_young_list_length()) {
547 if (collector_state()->gcs_are_young()) {
548 young_list_target_length =
549 calculate_young_list_target_length(rs_lengths,
550 base_min_length,
551 desired_min_length,
552 desired_max_length);
553 _rs_lengths_prediction = rs_lengths;
554 } else {
555 // Don't calculate anything and let the code below bound it to
556 // the desired_min_length, i.e., do the next GC as soon as
557 // possible to maximize how many old regions we can add to it.
558 }
559 } else {
560 // The user asked for a fixed young gen so we'll fix the young gen
561 // whether the next GC is young or mixed.
562 young_list_target_length = _young_list_fixed_length;
563 }
564
565 // Make sure we don't go over the desired max length, nor under the
566 // desired min length. In case they clash, desired_min_length wins
567 // which is why that test is second.
568 if (young_list_target_length > desired_max_length) {
569 young_list_target_length = desired_max_length;
570 }
571 if (young_list_target_length < desired_min_length) {
572 young_list_target_length = desired_min_length;
573 }
574
575 assert(young_list_target_length > recorded_survivor_regions(),
576 "we should be able to allocate at least one eden region");
577 assert(young_list_target_length >= absolute_min_length, "post-condition");
578 _young_list_target_length = young_list_target_length;
579
580 update_max_gc_locker_expansion();
581 }
582
583 uint
584 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
585 uint base_min_length,
586 uint desired_min_length,
587 uint desired_max_length) {
588 assert(adaptive_young_list_length(), "pre-condition");
589 assert(collector_state()->gcs_are_young(), "only call this for young GCs");
590
591 // In case some edge-condition makes the desired max length too small...
592 if (desired_max_length <= desired_min_length) {
593 return desired_min_length;
594 }
595
596 // We'll adjust min_young_length and max_young_length not to include
597 // the already allocated young regions (i.e., so they reflect the
598 // min and max eden regions we'll allocate). The base_min_length
599 // will be reflected in the predictions by the
600 // survivor_regions_evac_time prediction.
601 assert(desired_min_length > base_min_length, "invariant");
602 uint min_young_length = desired_min_length - base_min_length;
603 assert(desired_max_length > base_min_length, "invariant");
604 uint max_young_length = desired_max_length - base_min_length;
605
606 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
607 double survivor_regions_evac_time = predict_survivor_regions_evac_time();
608 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
609 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
610 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
611 double base_time_ms =
612 predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
613 survivor_regions_evac_time;
614 uint available_free_regions = _free_regions_at_end_of_collection;
615 uint base_free_regions = 0;
616 if (available_free_regions > _reserve_regions) {
617 base_free_regions = available_free_regions - _reserve_regions;
618 }
619
620 // Here, we will make sure that the shortest young length that
621 // makes sense fits within the target pause time.
622
623 if (predict_will_fit(min_young_length, base_time_ms,
624 base_free_regions, target_pause_time_ms)) {
625 // The shortest young length will fit into the target pause time;
626 // we'll now check whether the absolute maximum number of young
627 // regions will fit in the target pause time. If not, we'll do
628 // a binary search between min_young_length and max_young_length.
629 if (predict_will_fit(max_young_length, base_time_ms,
630 base_free_regions, target_pause_time_ms)) {
631 // The maximum young length will fit into the target pause time.
632 // We are done so set min young length to the maximum length (as
633 // the result is assumed to be returned in min_young_length).
634 min_young_length = max_young_length;
635 } else {
636 // The maximum possible number of young regions will not fit within
637 // the target pause time so we'll search for the optimal
638 // length. The loop invariants are:
639 //
640 // min_young_length < max_young_length
641 // min_young_length is known to fit into the target pause time
642 // max_young_length is known not to fit into the target pause time
643 //
644 // Going into the loop we know the above hold as we've just
645 // checked them. Every time around the loop we check whether
646 // the middle value between min_young_length and
647 // max_young_length fits into the target pause time. If it
648 // does, it becomes the new min. If it doesn't, it becomes
649 // the new max. This way we maintain the loop invariants.
650
651 assert(min_young_length < max_young_length, "invariant");
652 uint diff = (max_young_length - min_young_length) / 2;
653 while (diff > 0) {
654 uint young_length = min_young_length + diff;
655 if (predict_will_fit(young_length, base_time_ms,
656 base_free_regions, target_pause_time_ms)) {
657 min_young_length = young_length;
658 } else {
659 max_young_length = young_length;
660 }
661 assert(min_young_length < max_young_length, "invariant");
662 diff = (max_young_length - min_young_length) / 2;
663 }
664 // The results is min_young_length which, according to the
665 // loop invariants, should fit within the target pause time.
666
667 // These are the post-conditions of the binary search above:
668 assert(min_young_length < max_young_length,
669 "otherwise we should have discovered that max_young_length "
670 "fits into the pause target and not done the binary search");
671 assert(predict_will_fit(min_young_length, base_time_ms,
672 base_free_regions, target_pause_time_ms),
673 "min_young_length, the result of the binary search, should "
674 "fit into the pause target");
675 assert(!predict_will_fit(min_young_length + 1, base_time_ms,
676 base_free_regions, target_pause_time_ms),
677 "min_young_length, the result of the binary search, should be "
678 "optimal, so no larger length should fit into the pause target");
679 }
680 } else {
681 // Even the minimum length doesn't fit into the pause time
682 // target, return it as the result nevertheless.
683 }
684 return base_min_length + min_young_length;
685 }
686
687 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
688 double survivor_regions_evac_time = 0.0;
689 for (HeapRegion * r = _recorded_survivor_head;
690 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
691 r = r->get_next_young_region()) {
692 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, collector_state()->gcs_are_young());
693 }
694 return survivor_regions_evac_time;
695 }
696
697 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
698 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
699
700 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
701 if (rs_lengths > _rs_lengths_prediction) {
702 // add 10% to avoid having to recalculate often
703 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
704 update_young_list_target_length(rs_lengths_prediction);
705 }
706 }
707
708
709
710 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
711 bool is_tlab,
712 bool* gc_overhead_limit_was_exceeded) {
713 guarantee(false, "Not using this policy feature yet.");
714 return NULL;
715 }
716
717 // This method controls how a collector handles one or more
718 // of its generations being fully allocated.
719 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
720 bool is_tlab) {
721 guarantee(false, "Not using this policy feature yet.");
722 return NULL;
723 }
724
725
726 #ifndef PRODUCT
727 bool G1CollectorPolicy::verify_young_ages() {
728 HeapRegion* head = _g1->young_list()->first_region();
729 return
730 verify_young_ages(head, _short_lived_surv_rate_group);
731 // also call verify_young_ages on any additional surv rate groups
732 }
733
734 bool
735 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
736 SurvRateGroup *surv_rate_group) {
737 guarantee( surv_rate_group != NULL, "pre-condition" );
738
739 const char* name = surv_rate_group->name();
740 bool ret = true;
741 int prev_age = -1;
742
743 for (HeapRegion* curr = head;
744 curr != NULL;
745 curr = curr->get_next_young_region()) {
746 SurvRateGroup* group = curr->surv_rate_group();
747 if (group == NULL && !curr->is_survivor()) {
748 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
749 ret = false;
750 }
751
752 if (surv_rate_group == group) {
753 int age = curr->age_in_surv_rate_group();
754
755 if (age < 0) {
756 gclog_or_tty->print_cr("## %s: encountered negative age", name);
757 ret = false;
758 }
759
760 if (age <= prev_age) {
761 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
762 "(%d, %d)", name, age, prev_age);
763 ret = false;
764 }
765 prev_age = age;
766 }
767 }
768
769 return ret;
770 }
771 #endif // PRODUCT
772
773 void G1CollectorPolicy::record_full_collection_start() {
774 _full_collection_start_sec = os::elapsedTime();
775 record_heap_size_info_at_start(true /* full */);
776 // Release the future to-space so that it is available for compaction into.
777 collector_state()->set_full_collection(true);
778 }
779
780 void G1CollectorPolicy::record_full_collection_end() {
781 // Consider this like a collection pause for the purposes of allocation
782 // since last pause.
783 double end_sec = os::elapsedTime();
784 double full_gc_time_sec = end_sec - _full_collection_start_sec;
785 double full_gc_time_ms = full_gc_time_sec * 1000.0;
786
787 _trace_old_gen_time_data.record_full_collection(full_gc_time_ms);
788
789 update_recent_gc_times(end_sec, full_gc_time_ms);
790
791 collector_state()->set_full_collection(false);
792
793 // "Nuke" the heuristics that control the young/mixed GC
794 // transitions and make sure we start with young GCs after the Full GC.
795 collector_state()->set_gcs_are_young(true);
796 collector_state()->set_last_young_gc(false);
797 collector_state()->set_initiate_conc_mark_if_possible(false);
798 collector_state()->set_during_initial_mark_pause(false);
799 collector_state()->set_in_marking_window(false);
800 collector_state()->set_in_marking_window_im(false);
801
802 _short_lived_surv_rate_group->start_adding_regions();
803 // also call this on any additional surv rate groups
804
805 record_survivor_regions(0, NULL, NULL);
806
807 _free_regions_at_end_of_collection = _g1->num_free_regions();
808 // Reset survivors SurvRateGroup.
809 _survivor_surv_rate_group->reset();
810 update_young_list_target_length();
811 _collectionSetChooser->clear();
812 }
813
814 void G1CollectorPolicy::record_stop_world_start() {
815 _stop_world_start = os::elapsedTime();
816 }
817
818 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
819 // We only need to do this here as the policy will only be applied
820 // to the GC we're about to start. so, no point is calculating this
821 // every time we calculate / recalculate the target young length.
822 update_survivors_policy();
823
824 assert(_g1->used() == _g1->recalculate_used(),
825 err_msg("sanity, used: " SIZE_FORMAT " recalculate_used: " SIZE_FORMAT,
826 _g1->used(), _g1->recalculate_used()));
827
828 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
829 _trace_young_gen_time_data.record_start_collection(s_w_t_ms);
830 _stop_world_start = 0.0;
831
832 record_heap_size_info_at_start(false /* full */);
833
834 phase_times()->record_cur_collection_start_sec(start_time_sec);
835 _pending_cards = _g1->pending_card_num();
836
837 _collection_set_bytes_used_before = 0;
838 _bytes_copied_during_gc = 0;
839
840 collector_state()->set_last_gc_was_young(false);
841
842 // do that for any other surv rate groups
843 _short_lived_surv_rate_group->stop_adding_regions();
844 _survivors_age_table.clear();
845
846 assert( verify_young_ages(), "region age verification" );
847 }
848
849 void G1CollectorPolicy::record_concurrent_mark_init_end(double
850 mark_init_elapsed_time_ms) {
851 collector_state()->set_during_marking(true);
852 assert(!collector_state()->initiate_conc_mark_if_possible(), "we should have cleared it by now");
853 collector_state()->set_during_initial_mark_pause(false);
854 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
855 }
856
857 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
858 _mark_remark_start_sec = os::elapsedTime();
859 collector_state()->set_during_marking(false);
860 }
861
862 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
863 double end_time_sec = os::elapsedTime();
864 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
865 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
866 _cur_mark_stop_world_time_ms += elapsed_time_ms;
867 _prev_collection_pause_end_ms += elapsed_time_ms;
868
869 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, _g1->gc_tracer_cm()->gc_id());
870 }
871
872 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
873 _mark_cleanup_start_sec = os::elapsedTime();
874 }
875
876 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
877 collector_state()->set_last_young_gc(true);
878 collector_state()->set_in_marking_window(false);
879 }
880
881 void G1CollectorPolicy::record_concurrent_pause() {
882 if (_stop_world_start > 0.0) {
883 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
884 _trace_young_gen_time_data.record_yield_time(yield_ms);
885 }
886 }
887
888 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
889 if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
890 return false;
891 }
892
893 size_t marking_initiating_used_threshold =
894 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
895 size_t cur_used_bytes = _g1->non_young_capacity_bytes();
896 size_t alloc_byte_size = alloc_word_size * HeapWordSize;
897
898 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
899 if (collector_state()->gcs_are_young() && !collector_state()->last_young_gc()) {
900 ergo_verbose5(ErgoConcCycles,
901 "request concurrent cycle initiation",
902 ergo_format_reason("occupancy higher than threshold")
903 ergo_format_byte("occupancy")
904 ergo_format_byte("allocation request")
905 ergo_format_byte_perc("threshold")
906 ergo_format_str("source"),
907 cur_used_bytes,
908 alloc_byte_size,
909 marking_initiating_used_threshold,
910 (double) InitiatingHeapOccupancyPercent,
911 source);
912 return true;
913 } else {
914 ergo_verbose5(ErgoConcCycles,
915 "do not request concurrent cycle initiation",
916 ergo_format_reason("still doing mixed collections")
917 ergo_format_byte("occupancy")
918 ergo_format_byte("allocation request")
919 ergo_format_byte_perc("threshold")
920 ergo_format_str("source"),
921 cur_used_bytes,
922 alloc_byte_size,
923 marking_initiating_used_threshold,
924 (double) InitiatingHeapOccupancyPercent,
925 source);
926 }
927 }
928
929 return false;
930 }
931
932 // Anything below that is considered to be zero
933 #define MIN_TIMER_GRANULARITY 0.0000001
934
935 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms) {
936 double end_time_sec = os::elapsedTime();
937 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
938 "otherwise, the subtraction below does not make sense");
939 size_t rs_size =
940 _cur_collection_pause_used_regions_at_start - cset_region_length();
941 size_t cur_used_bytes = _g1->used();
942 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
943 bool last_pause_included_initial_mark = false;
944 bool update_stats = !_g1->evacuation_failed();
945
946 #ifndef PRODUCT
947 if (G1YoungSurvRateVerbose) {
948 gclog_or_tty->cr();
949 _short_lived_surv_rate_group->print();
950 // do that for any other surv rate groups too
951 }
952 #endif // PRODUCT
953
954 last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
955 if (last_pause_included_initial_mark) {
956 record_concurrent_mark_init_end(0.0);
957 } else if (need_to_start_conc_mark("end of GC")) {
958 // Note: this might have already been set, if during the last
959 // pause we decided to start a cycle but at the beginning of
960 // this pause we decided to postpone it. That's OK.
961 collector_state()->set_initiate_conc_mark_if_possible(true);
962 }
963
964 _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0,
965 end_time_sec, _g1->gc_tracer_stw()->gc_id());
966
967 if (update_stats) {
968 _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times());
969 // this is where we update the allocation rate of the application
970 double app_time_ms =
971 (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
972 if (app_time_ms < MIN_TIMER_GRANULARITY) {
973 // This usually happens due to the timer not having the required
974 // granularity. Some Linuxes are the usual culprits.
975 // We'll just set it to something (arbitrarily) small.
976 app_time_ms = 1.0;
977 }
978 // We maintain the invariant that all objects allocated by mutator
979 // threads will be allocated out of eden regions. So, we can use
980 // the eden region number allocated since the previous GC to
981 // calculate the application's allocate rate. The only exception
982 // to that is humongous objects that are allocated separately. But
983 // given that humongous object allocations do not really affect
984 // either the pause's duration nor when the next pause will take
985 // place we can safely ignore them here.
986 uint regions_allocated = eden_cset_region_length();
987 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
988 _alloc_rate_ms_seq->add(alloc_rate_ms);
989
990 double interval_ms =
991 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
992 update_recent_gc_times(end_time_sec, pause_time_ms);
993 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
994 if (recent_avg_pause_time_ratio() < 0.0 ||
995 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
996 #ifndef PRODUCT
997 // Dump info to allow post-facto debugging
998 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
999 gclog_or_tty->print_cr("-------------------------------------------");
1000 gclog_or_tty->print_cr("Recent GC Times (ms):");
1001 _recent_gc_times_ms->dump();
1002 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1003 _recent_prev_end_times_for_all_gcs_sec->dump();
1004 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1005 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1006 // In debug mode, terminate the JVM if the user wants to debug at this point.
1007 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1008 #endif // !PRODUCT
1009 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1010 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1011 if (_recent_avg_pause_time_ratio < 0.0) {
1012 _recent_avg_pause_time_ratio = 0.0;
1013 } else {
1014 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1015 _recent_avg_pause_time_ratio = 1.0;
1016 }
1017 }
1018 }
1019
1020 bool new_in_marking_window = collector_state()->in_marking_window();
1021 bool new_in_marking_window_im = false;
1022 if (last_pause_included_initial_mark) {
1023 new_in_marking_window = true;
1024 new_in_marking_window_im = true;
1025 }
1026
1027 if (collector_state()->last_young_gc()) {
1028 // This is supposed to to be the "last young GC" before we start
1029 // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1030
1031 if (!last_pause_included_initial_mark) {
1032 if (next_gc_should_be_mixed("start mixed GCs",
1033 "do not start mixed GCs")) {
1034 collector_state()->set_gcs_are_young(false);
1035 }
1036 } else {
1037 ergo_verbose0(ErgoMixedGCs,
1038 "do not start mixed GCs",
1039 ergo_format_reason("concurrent cycle is about to start"));
1040 }
1041 collector_state()->set_last_young_gc(false);
1042 }
1043
1044 if (!collector_state()->last_gc_was_young()) {
1045 // This is a mixed GC. Here we decide whether to continue doing
1046 // mixed GCs or not.
1047
1048 if (!next_gc_should_be_mixed("continue mixed GCs",
1049 "do not continue mixed GCs")) {
1050 collector_state()->set_gcs_are_young(true);
1051 }
1052 }
1053
1054 _short_lived_surv_rate_group->start_adding_regions();
1055 // Do that for any other surv rate groups
1056
1057 if (update_stats) {
1058 double cost_per_card_ms = 0.0;
1059 if (_pending_cards > 0) {
1060 cost_per_card_ms = phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS) / (double) _pending_cards;
1061 _cost_per_card_ms_seq->add(cost_per_card_ms);
1062 }
1063
1064 size_t cards_scanned = _g1->cards_scanned();
1065
1066 double cost_per_entry_ms = 0.0;
1067 if (cards_scanned > 10) {
1068 cost_per_entry_ms = phase_times()->average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
1069 if (collector_state()->last_gc_was_young()) {
1070 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1071 } else {
1072 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1073 }
1074 }
1075
1076 if (_max_rs_lengths > 0) {
1077 double cards_per_entry_ratio =
1078 (double) cards_scanned / (double) _max_rs_lengths;
1079 if (collector_state()->last_gc_was_young()) {
1080 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1081 } else {
1082 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1083 }
1084 }
1085
1086 // This is defensive. For a while _max_rs_lengths could get
1087 // smaller than _recorded_rs_lengths which was causing
1088 // rs_length_diff to get very large and mess up the RSet length
1089 // predictions. The reason was unsafe concurrent updates to the
1090 // _inc_cset_recorded_rs_lengths field which the code below guards
1091 // against (see CR 7118202). This bug has now been fixed (see CR
1092 // 7119027). However, I'm still worried that
1093 // _inc_cset_recorded_rs_lengths might still end up somewhat
1094 // inaccurate. The concurrent refinement thread calculates an
1095 // RSet's length concurrently with other CR threads updating it
1096 // which might cause it to calculate the length incorrectly (if,
1097 // say, it's in mid-coarsening). So I'll leave in the defensive
1098 // conditional below just in case.
1099 size_t rs_length_diff = 0;
1100 if (_max_rs_lengths > _recorded_rs_lengths) {
1101 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1102 }
1103 _rs_length_diff_seq->add((double) rs_length_diff);
1104
1105 size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1106 size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1107 double cost_per_byte_ms = 0.0;
1108
1109 if (copied_bytes > 0) {
1110 cost_per_byte_ms = phase_times()->average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
1111 if (collector_state()->in_marking_window()) {
1112 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1113 } else {
1114 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1115 }
1116 }
1117
1118 double all_other_time_ms = pause_time_ms -
1119 (phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS) + phase_times()->average_time_ms(G1GCPhaseTimes::ScanRS) +
1120 phase_times()->average_time_ms(G1GCPhaseTimes::ObjCopy) + phase_times()->average_time_ms(G1GCPhaseTimes::Termination));
1121
1122 double young_other_time_ms = 0.0;
1123 if (young_cset_region_length() > 0) {
1124 young_other_time_ms =
1125 phase_times()->young_cset_choice_time_ms() +
1126 phase_times()->young_free_cset_time_ms();
1127 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1128 (double) young_cset_region_length());
1129 }
1130 double non_young_other_time_ms = 0.0;
1131 if (old_cset_region_length() > 0) {
1132 non_young_other_time_ms =
1133 phase_times()->non_young_cset_choice_time_ms() +
1134 phase_times()->non_young_free_cset_time_ms();
1135
1136 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1137 (double) old_cset_region_length());
1138 }
1139
1140 double constant_other_time_ms = all_other_time_ms -
1141 (young_other_time_ms + non_young_other_time_ms);
1142 _constant_other_time_ms_seq->add(constant_other_time_ms);
1143
1144 double survival_ratio = 0.0;
1145 if (_collection_set_bytes_used_before > 0) {
1146 survival_ratio = (double) _bytes_copied_during_gc /
1147 (double) _collection_set_bytes_used_before;
1148 }
1149
1150 _pending_cards_seq->add((double) _pending_cards);
1151 _rs_lengths_seq->add((double) _max_rs_lengths);
1152 }
1153
1154 collector_state()->set_in_marking_window(new_in_marking_window);
1155 collector_state()->set_in_marking_window_im(new_in_marking_window_im);
1156 _free_regions_at_end_of_collection = _g1->num_free_regions();
1157 update_young_list_target_length();
1158
1159 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1160 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1161 adjust_concurrent_refinement(phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS),
1162 phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS), update_rs_time_goal_ms);
1163
1164 _collectionSetChooser->verify();
1165 }
1166
1167 #define EXT_SIZE_FORMAT "%.1f%s"
1168 #define EXT_SIZE_PARAMS(bytes) \
1169 byte_size_in_proper_unit((double)(bytes)), \
1170 proper_unit_for_byte_size((bytes))
1171
1172 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1173 YoungList* young_list = _g1->young_list();
1174 _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1175 _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1176 _heap_capacity_bytes_before_gc = _g1->capacity();
1177 _heap_used_bytes_before_gc = _g1->used();
1178 _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1179
1180 _eden_capacity_bytes_before_gc =
1181 (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1182
1183 if (full) {
1184 _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1185 }
1186 }
1187
1188 void G1CollectorPolicy::print_heap_transition(size_t bytes_before) {
1189 size_t bytes_after = _g1->used();
1190 size_t capacity = _g1->capacity();
1191
1192 gclog_or_tty->print(" " SIZE_FORMAT "%s->" SIZE_FORMAT "%s(" SIZE_FORMAT "%s)",
1193 byte_size_in_proper_unit(bytes_before),
1194 proper_unit_for_byte_size(bytes_before),
1195 byte_size_in_proper_unit(bytes_after),
1196 proper_unit_for_byte_size(bytes_after),
1197 byte_size_in_proper_unit(capacity),
1198 proper_unit_for_byte_size(capacity));
1199 }
1200
1201 void G1CollectorPolicy::print_heap_transition() {
1202 print_heap_transition(_heap_used_bytes_before_gc);
1203 }
1204
1205 void G1CollectorPolicy::print_detailed_heap_transition(bool full) {
1206 YoungList* young_list = _g1->young_list();
1207
1208 size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1209 size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1210 size_t heap_used_bytes_after_gc = _g1->used();
1211
1212 size_t heap_capacity_bytes_after_gc = _g1->capacity();
1213 size_t eden_capacity_bytes_after_gc =
1214 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1215
1216 gclog_or_tty->print(
1217 " [Eden: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->" EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ") "
1218 "Survivors: " EXT_SIZE_FORMAT "->" EXT_SIZE_FORMAT " "
1219 "Heap: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->"
1220 EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")]",
1221 EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1222 EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1223 EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1224 EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1225 EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1226 EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1227 EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1228 EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1229 EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1230 EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1231
1232 if (full) {
1233 MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1234 }
1235
1236 gclog_or_tty->cr();
1237 }
1238
1239 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1240 double update_rs_processed_buffers,
1241 double goal_ms) {
1242 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1243 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1244
1245 if (G1UseAdaptiveConcRefinement) {
1246 const int k_gy = 3, k_gr = 6;
1247 const double inc_k = 1.1, dec_k = 0.9;
1248
1249 int g = cg1r->green_zone();
1250 if (update_rs_time > goal_ms) {
1251 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1252 } else {
1253 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1254 g = (int)MAX2(g * inc_k, g + 1.0);
1255 }
1256 }
1257 // Change the refinement threads params
1258 cg1r->set_green_zone(g);
1259 cg1r->set_yellow_zone(g * k_gy);
1260 cg1r->set_red_zone(g * k_gr);
1261 cg1r->reinitialize_threads();
1262
1263 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1264 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1265 cg1r->yellow_zone());
1266 // Change the barrier params
1267 dcqs.set_process_completed_threshold(processing_threshold);
1268 dcqs.set_max_completed_queue(cg1r->red_zone());
1269 }
1270
1271 int curr_queue_size = dcqs.completed_buffers_num();
1272 if (curr_queue_size >= cg1r->yellow_zone()) {
1273 dcqs.set_completed_queue_padding(curr_queue_size);
1274 } else {
1275 dcqs.set_completed_queue_padding(0);
1276 }
1277 dcqs.notify_if_necessary();
1278 }
1279
1280 double
1281 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1282 size_t scanned_cards) {
1283 return
1284 predict_rs_update_time_ms(pending_cards) +
1285 predict_rs_scan_time_ms(scanned_cards) +
1286 predict_constant_other_time_ms();
1287 }
1288
1289 double
1290 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1291 size_t rs_length = predict_rs_length_diff();
1292 size_t card_num;
1293 if (collector_state()->gcs_are_young()) {
1294 card_num = predict_young_card_num(rs_length);
1295 } else {
1296 card_num = predict_non_young_card_num(rs_length);
1297 }
1298 return predict_base_elapsed_time_ms(pending_cards, card_num);
1299 }
1300
1301 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1302 size_t bytes_to_copy;
1303 if (hr->is_marked())
1304 bytes_to_copy = hr->max_live_bytes();
1305 else {
1306 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1307 int age = hr->age_in_surv_rate_group();
1308 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1309 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1310 }
1311 return bytes_to_copy;
1312 }
1313
1314 double
1315 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1316 bool for_young_gc) {
1317 size_t rs_length = hr->rem_set()->occupied();
1318 size_t card_num;
1319
1320 // Predicting the number of cards is based on which type of GC
1321 // we're predicting for.
1322 if (for_young_gc) {
1323 card_num = predict_young_card_num(rs_length);
1324 } else {
1325 card_num = predict_non_young_card_num(rs_length);
1326 }
1327 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1328
1329 double region_elapsed_time_ms =
1330 predict_rs_scan_time_ms(card_num) +
1331 predict_object_copy_time_ms(bytes_to_copy);
1332
1333 // The prediction of the "other" time for this region is based
1334 // upon the region type and NOT the GC type.
1335 if (hr->is_young()) {
1336 region_elapsed_time_ms += predict_young_other_time_ms(1);
1337 } else {
1338 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1339 }
1340 return region_elapsed_time_ms;
1341 }
1342
1343 void
1344 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1345 uint survivor_cset_region_length) {
1346 _eden_cset_region_length = eden_cset_region_length;
1347 _survivor_cset_region_length = survivor_cset_region_length;
1348 _old_cset_region_length = 0;
1349 }
1350
1351 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1352 _recorded_rs_lengths = rs_lengths;
1353 }
1354
1355 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1356 double elapsed_ms) {
1357 _recent_gc_times_ms->add(elapsed_ms);
1358 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1359 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1360 }
1361
1362 size_t G1CollectorPolicy::expansion_amount() {
1363 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1364 double threshold = _gc_overhead_perc;
1365 if (recent_gc_overhead > threshold) {
1366 // We will double the existing space, or take
1367 // G1ExpandByPercentOfAvailable % of the available expansion
1368 // space, whichever is smaller, bounded below by a minimum
1369 // expansion (unless that's all that's left.)
1370 const size_t min_expand_bytes = 1*M;
1371 size_t reserved_bytes = _g1->max_capacity();
1372 size_t committed_bytes = _g1->capacity();
1373 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1374 size_t expand_bytes;
1375 size_t expand_bytes_via_pct =
1376 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1377 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1378 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1379 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1380
1381 ergo_verbose5(ErgoHeapSizing,
1382 "attempt heap expansion",
1383 ergo_format_reason("recent GC overhead higher than "
1384 "threshold after GC")
1385 ergo_format_perc("recent GC overhead")
1386 ergo_format_perc("threshold")
1387 ergo_format_byte("uncommitted")
1388 ergo_format_byte_perc("calculated expansion amount"),
1389 recent_gc_overhead, threshold,
1390 uncommitted_bytes,
1391 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1392
1393 return expand_bytes;
1394 } else {
1395 return 0;
1396 }
1397 }
1398
1399 void G1CollectorPolicy::print_tracing_info() const {
1400 _trace_young_gen_time_data.print();
1401 _trace_old_gen_time_data.print();
1402 }
1403
1404 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1405 #ifndef PRODUCT
1406 _short_lived_surv_rate_group->print_surv_rate_summary();
1407 // add this call for any other surv rate groups
1408 #endif // PRODUCT
1409 }
1410
1411 bool G1CollectorPolicy::is_young_list_full() {
1412 uint young_list_length = _g1->young_list()->length();
1413 uint young_list_target_length = _young_list_target_length;
1414 return young_list_length >= young_list_target_length;
1415 }
1416
1417 bool G1CollectorPolicy::can_expand_young_list() {
1418 uint young_list_length = _g1->young_list()->length();
1419 uint young_list_max_length = _young_list_max_length;
1420 return young_list_length < young_list_max_length;
1421 }
1422
1423 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1424 uint expansion_region_num = 0;
1425 if (GCLockerEdenExpansionPercent > 0) {
1426 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1427 double expansion_region_num_d = perc * (double) _young_list_target_length;
1428 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1429 // less than 1.0) we'll get 1.
1430 expansion_region_num = (uint) ceil(expansion_region_num_d);
1431 } else {
1432 assert(expansion_region_num == 0, "sanity");
1433 }
1434 _young_list_max_length = _young_list_target_length + expansion_region_num;
1435 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1436 }
1437
1438 // Calculates survivor space parameters.
1439 void G1CollectorPolicy::update_survivors_policy() {
1440 double max_survivor_regions_d =
1441 (double) _young_list_target_length / (double) SurvivorRatio;
1442 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1443 // smaller than 1.0) we'll get 1.
1444 _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1445
1446 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1447 HeapRegion::GrainWords * _max_survivor_regions, counters());
1448 }
1449
1450 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
1451 GCCause::Cause gc_cause) {
1452 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1453 if (!during_cycle) {
1454 ergo_verbose1(ErgoConcCycles,
1455 "request concurrent cycle initiation",
1456 ergo_format_reason("requested by GC cause")
1457 ergo_format_str("GC cause"),
1458 GCCause::to_string(gc_cause));
1459 collector_state()->set_initiate_conc_mark_if_possible(true);
1460 return true;
1461 } else {
1462 ergo_verbose1(ErgoConcCycles,
1463 "do not request concurrent cycle initiation",
1464 ergo_format_reason("concurrent cycle already in progress")
1465 ergo_format_str("GC cause"),
1466 GCCause::to_string(gc_cause));
1467 return false;
1468 }
1469 }
1470
1471 void
1472 G1CollectorPolicy::decide_on_conc_mark_initiation() {
1473 // We are about to decide on whether this pause will be an
1474 // initial-mark pause.
1475
1476 // First, collector_state()->during_initial_mark_pause() should not be already set. We
1477 // will set it here if we have to. However, it should be cleared by
1478 // the end of the pause (it's only set for the duration of an
1479 // initial-mark pause).
1480 assert(!collector_state()->during_initial_mark_pause(), "pre-condition");
1481
1482 if (collector_state()->initiate_conc_mark_if_possible()) {
1483 // We had noticed on a previous pause that the heap occupancy has
1484 // gone over the initiating threshold and we should start a
1485 // concurrent marking cycle. So we might initiate one.
1486
1487 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1488 if (!during_cycle) {
1489 // The concurrent marking thread is not "during a cycle", i.e.,
1490 // it has completed the last one. So we can go ahead and
1491 // initiate a new cycle.
1492
1493 collector_state()->set_during_initial_mark_pause(true);
1494 // We do not allow mixed GCs during marking.
1495 if (!collector_state()->gcs_are_young()) {
1496 collector_state()->set_gcs_are_young(true);
1497 ergo_verbose0(ErgoMixedGCs,
1498 "end mixed GCs",
1499 ergo_format_reason("concurrent cycle is about to start"));
1500 }
1501
1502 // And we can now clear initiate_conc_mark_if_possible() as
1503 // we've already acted on it.
1504 collector_state()->set_initiate_conc_mark_if_possible(false);
1505
1506 ergo_verbose0(ErgoConcCycles,
1507 "initiate concurrent cycle",
1508 ergo_format_reason("concurrent cycle initiation requested"));
1509 } else {
1510 // The concurrent marking thread is still finishing up the
1511 // previous cycle. If we start one right now the two cycles
1512 // overlap. In particular, the concurrent marking thread might
1513 // be in the process of clearing the next marking bitmap (which
1514 // we will use for the next cycle if we start one). Starting a
1515 // cycle now will be bad given that parts of the marking
1516 // information might get cleared by the marking thread. And we
1517 // cannot wait for the marking thread to finish the cycle as it
1518 // periodically yields while clearing the next marking bitmap
1519 // and, if it's in a yield point, it's waiting for us to
1520 // finish. So, at this point we will not start a cycle and we'll
1521 // let the concurrent marking thread complete the last one.
1522 ergo_verbose0(ErgoConcCycles,
1523 "do not initiate concurrent cycle",
1524 ergo_format_reason("concurrent cycle already in progress"));
1525 }
1526 }
1527 }
1528
1529 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1530 G1CollectedHeap* _g1h;
1531 CSetChooserParUpdater _cset_updater;
1532
1533 public:
1534 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1535 uint chunk_size) :
1536 _g1h(G1CollectedHeap::heap()),
1537 _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1538
1539 bool doHeapRegion(HeapRegion* r) {
1540 // Do we have any marking information for this region?
1541 if (r->is_marked()) {
1542 // We will skip any region that's currently used as an old GC
1543 // alloc region (we should not consider those for collection
1544 // before we fill them up).
1545 if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1546 _cset_updater.add_region(r);
1547 }
1548 }
1549 return false;
1550 }
1551 };
1552
1553 class ParKnownGarbageTask: public AbstractGangTask {
1554 CollectionSetChooser* _hrSorted;
1555 uint _chunk_size;
1556 G1CollectedHeap* _g1;
1557 HeapRegionClaimer _hrclaimer;
1558
1559 public:
1560 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
1561 AbstractGangTask("ParKnownGarbageTask"),
1562 _hrSorted(hrSorted), _chunk_size(chunk_size),
1563 _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
1564
1565 void work(uint worker_id) {
1566 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1567 _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
1568 }
1569 };
1570
1571 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) {
1572 assert(n_workers > 0, "Active gc workers should be greater than 0");
1573 const uint overpartition_factor = 4;
1574 const uint min_chunk_size = MAX2(n_regions / n_workers, 1U);
1575 return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size);
1576 }
1577
1578 void
1579 G1CollectorPolicy::record_concurrent_mark_cleanup_end() {
1580 _collectionSetChooser->clear();
1581
1582 WorkGang* workers = _g1->workers();
1583 uint n_workers = workers->active_workers();
1584
1585 uint n_regions = _g1->num_regions();
1586 uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions);
1587 _collectionSetChooser->prepare_for_par_region_addition(n_workers, n_regions, chunk_size);
1588 ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers);
1589 workers->run_task(&par_known_garbage_task);
1590
1591 _collectionSetChooser->sort_regions();
1592
1593 double end_sec = os::elapsedTime();
1594 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1595 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1596 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1597 _prev_collection_pause_end_ms += elapsed_time_ms;
1598 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, _g1->gc_tracer_cm()->gc_id());
1599 }
1600
1601 // Add the heap region at the head of the non-incremental collection set
1602 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1603 assert(_inc_cset_build_state == Active, "Precondition");
1604 assert(hr->is_old(), "the region should be old");
1605
1606 assert(!hr->in_collection_set(), "should not already be in the CSet");
1607 _g1->register_old_region_with_cset(hr);
1608 hr->set_next_in_collection_set(_collection_set);
1609 _collection_set = hr;
1610 _collection_set_bytes_used_before += hr->used();
1611 size_t rs_length = hr->rem_set()->occupied();
1612 _recorded_rs_lengths += rs_length;
1613 _old_cset_region_length += 1;
1614 }
1615
1616 // Initialize the per-collection-set information
1617 void G1CollectorPolicy::start_incremental_cset_building() {
1618 assert(_inc_cset_build_state == Inactive, "Precondition");
1619
1620 _inc_cset_head = NULL;
1621 _inc_cset_tail = NULL;
1622 _inc_cset_bytes_used_before = 0;
1623
1624 _inc_cset_max_finger = 0;
1625 _inc_cset_recorded_rs_lengths = 0;
1626 _inc_cset_recorded_rs_lengths_diffs = 0;
1627 _inc_cset_predicted_elapsed_time_ms = 0.0;
1628 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1629 _inc_cset_build_state = Active;
1630 }
1631
1632 void G1CollectorPolicy::finalize_incremental_cset_building() {
1633 assert(_inc_cset_build_state == Active, "Precondition");
1634 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1635
1636 // The two "main" fields, _inc_cset_recorded_rs_lengths and
1637 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1638 // that adds a new region to the CSet. Further updates by the
1639 // concurrent refinement thread that samples the young RSet lengths
1640 // are accumulated in the *_diffs fields. Here we add the diffs to
1641 // the "main" fields.
1642
1643 if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1644 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1645 } else {
1646 // This is defensive. The diff should in theory be always positive
1647 // as RSets can only grow between GCs. However, given that we
1648 // sample their size concurrently with other threads updating them
1649 // it's possible that we might get the wrong size back, which
1650 // could make the calculations somewhat inaccurate.
1651 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1652 if (_inc_cset_recorded_rs_lengths >= diffs) {
1653 _inc_cset_recorded_rs_lengths -= diffs;
1654 } else {
1655 _inc_cset_recorded_rs_lengths = 0;
1656 }
1657 }
1658 _inc_cset_predicted_elapsed_time_ms +=
1659 _inc_cset_predicted_elapsed_time_ms_diffs;
1660
1661 _inc_cset_recorded_rs_lengths_diffs = 0;
1662 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1663 }
1664
1665 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1666 // This routine is used when:
1667 // * adding survivor regions to the incremental cset at the end of an
1668 // evacuation pause,
1669 // * adding the current allocation region to the incremental cset
1670 // when it is retired, and
1671 // * updating existing policy information for a region in the
1672 // incremental cset via young list RSet sampling.
1673 // Therefore this routine may be called at a safepoint by the
1674 // VM thread, or in-between safepoints by mutator threads (when
1675 // retiring the current allocation region) or a concurrent
1676 // refine thread (RSet sampling).
1677
1678 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1679 size_t used_bytes = hr->used();
1680 _inc_cset_recorded_rs_lengths += rs_length;
1681 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1682 _inc_cset_bytes_used_before += used_bytes;
1683
1684 // Cache the values we have added to the aggregated information
1685 // in the heap region in case we have to remove this region from
1686 // the incremental collection set, or it is updated by the
1687 // rset sampling code
1688 hr->set_recorded_rs_length(rs_length);
1689 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1690 }
1691
1692 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1693 size_t new_rs_length) {
1694 // Update the CSet information that is dependent on the new RS length
1695 assert(hr->is_young(), "Precondition");
1696 assert(!SafepointSynchronize::is_at_safepoint(),
1697 "should not be at a safepoint");
1698
1699 // We could have updated _inc_cset_recorded_rs_lengths and
1700 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1701 // that atomically, as this code is executed by a concurrent
1702 // refinement thread, potentially concurrently with a mutator thread
1703 // allocating a new region and also updating the same fields. To
1704 // avoid the atomic operations we accumulate these updates on two
1705 // separate fields (*_diffs) and we'll just add them to the "main"
1706 // fields at the start of a GC.
1707
1708 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1709 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1710 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1711
1712 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1713 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1714 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1715 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1716
1717 hr->set_recorded_rs_length(new_rs_length);
1718 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1719 }
1720
1721 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1722 assert(hr->is_young(), "invariant");
1723 assert(hr->young_index_in_cset() > -1, "should have already been set");
1724 assert(_inc_cset_build_state == Active, "Precondition");
1725
1726 // We need to clear and set the cached recorded/cached collection set
1727 // information in the heap region here (before the region gets added
1728 // to the collection set). An individual heap region's cached values
1729 // are calculated, aggregated with the policy collection set info,
1730 // and cached in the heap region here (initially) and (subsequently)
1731 // by the Young List sampling code.
1732
1733 size_t rs_length = hr->rem_set()->occupied();
1734 add_to_incremental_cset_info(hr, rs_length);
1735
1736 HeapWord* hr_end = hr->end();
1737 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1738
1739 assert(!hr->in_collection_set(), "invariant");
1740 _g1->register_young_region_with_cset(hr);
1741 assert(hr->next_in_collection_set() == NULL, "invariant");
1742 }
1743
1744 // Add the region at the RHS of the incremental cset
1745 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1746 // We should only ever be appending survivors at the end of a pause
1747 assert(hr->is_survivor(), "Logic");
1748
1749 // Do the 'common' stuff
1750 add_region_to_incremental_cset_common(hr);
1751
1752 // Now add the region at the right hand side
1753 if (_inc_cset_tail == NULL) {
1754 assert(_inc_cset_head == NULL, "invariant");
1755 _inc_cset_head = hr;
1756 } else {
1757 _inc_cset_tail->set_next_in_collection_set(hr);
1758 }
1759 _inc_cset_tail = hr;
1760 }
1761
1762 // Add the region to the LHS of the incremental cset
1763 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1764 // Survivors should be added to the RHS at the end of a pause
1765 assert(hr->is_eden(), "Logic");
1766
1767 // Do the 'common' stuff
1768 add_region_to_incremental_cset_common(hr);
1769
1770 // Add the region at the left hand side
1771 hr->set_next_in_collection_set(_inc_cset_head);
1772 if (_inc_cset_head == NULL) {
1773 assert(_inc_cset_tail == NULL, "Invariant");
1774 _inc_cset_tail = hr;
1775 }
1776 _inc_cset_head = hr;
1777 }
1778
1779 #ifndef PRODUCT
1780 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1781 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1782
1783 st->print_cr("\nCollection_set:");
1784 HeapRegion* csr = list_head;
1785 while (csr != NULL) {
1786 HeapRegion* next = csr->next_in_collection_set();
1787 assert(csr->in_collection_set(), "bad CS");
1788 st->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d",
1789 HR_FORMAT_PARAMS(csr),
1790 p2i(csr->prev_top_at_mark_start()), p2i(csr->next_top_at_mark_start()),
1791 csr->age_in_surv_rate_group_cond());
1792 csr = next;
1793 }
1794 }
1795 #endif // !PRODUCT
1796
1797 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) {
1798 // Returns the given amount of reclaimable bytes (that represents
1799 // the amount of reclaimable space still to be collected) as a
1800 // percentage of the current heap capacity.
1801 size_t capacity_bytes = _g1->capacity();
1802 return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1803 }
1804
1805 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1806 const char* false_action_str) {
1807 CollectionSetChooser* cset_chooser = _collectionSetChooser;
1808 if (cset_chooser->is_empty()) {
1809 ergo_verbose0(ErgoMixedGCs,
1810 false_action_str,
1811 ergo_format_reason("candidate old regions not available"));
1812 return false;
1813 }
1814
1815 // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1816 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1817 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1818 double threshold = (double) G1HeapWastePercent;
1819 if (reclaimable_perc <= threshold) {
1820 ergo_verbose4(ErgoMixedGCs,
1821 false_action_str,
1822 ergo_format_reason("reclaimable percentage not over threshold")
1823 ergo_format_region("candidate old regions")
1824 ergo_format_byte_perc("reclaimable")
1825 ergo_format_perc("threshold"),
1826 cset_chooser->remaining_regions(),
1827 reclaimable_bytes,
1828 reclaimable_perc, threshold);
1829 return false;
1830 }
1831
1832 ergo_verbose4(ErgoMixedGCs,
1833 true_action_str,
1834 ergo_format_reason("candidate old regions available")
1835 ergo_format_region("candidate old regions")
1836 ergo_format_byte_perc("reclaimable")
1837 ergo_format_perc("threshold"),
1838 cset_chooser->remaining_regions(),
1839 reclaimable_bytes,
1840 reclaimable_perc, threshold);
1841 return true;
1842 }
1843
1844 uint G1CollectorPolicy::calc_min_old_cset_length() {
1845 // The min old CSet region bound is based on the maximum desired
1846 // number of mixed GCs after a cycle. I.e., even if some old regions
1847 // look expensive, we should add them to the CSet anyway to make
1848 // sure we go through the available old regions in no more than the
1849 // maximum desired number of mixed GCs.
1850 //
1851 // The calculation is based on the number of marked regions we added
1852 // to the CSet chooser in the first place, not how many remain, so
1853 // that the result is the same during all mixed GCs that follow a cycle.
1854
1855 const size_t region_num = (size_t) _collectionSetChooser->length();
1856 const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
1857 size_t result = region_num / gc_num;
1858 // emulate ceiling
1859 if (result * gc_num < region_num) {
1860 result += 1;
1861 }
1862 return (uint) result;
1863 }
1864
1865 uint G1CollectorPolicy::calc_max_old_cset_length() {
1866 // The max old CSet region bound is based on the threshold expressed
1867 // as a percentage of the heap size. I.e., it should bound the
1868 // number of old regions added to the CSet irrespective of how many
1869 // of them are available.
1870
1871 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1872 const size_t region_num = g1h->num_regions();
1873 const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
1874 size_t result = region_num * perc / 100;
1875 // emulate ceiling
1876 if (100 * result < region_num * perc) {
1877 result += 1;
1878 }
1879 return (uint) result;
1880 }
1881
1882
1883 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
1884 double young_start_time_sec = os::elapsedTime();
1885
1886 YoungList* young_list = _g1->young_list();
1887 finalize_incremental_cset_building();
1888
1889 guarantee(target_pause_time_ms > 0.0,
1890 err_msg("target_pause_time_ms = %1.6lf should be positive",
1891 target_pause_time_ms));
1892 guarantee(_collection_set == NULL, "Precondition");
1893
1894 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
1895 double predicted_pause_time_ms = base_time_ms;
1896 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
1897
1898 ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
1899 "start choosing CSet",
1900 ergo_format_size("_pending_cards")
1901 ergo_format_ms("predicted base time")
1902 ergo_format_ms("remaining time")
1903 ergo_format_ms("target pause time"),
1904 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
1905
1906 collector_state()->set_last_gc_was_young(collector_state()->gcs_are_young());
1907
1908 if (collector_state()->last_gc_was_young()) {
1909 _trace_young_gen_time_data.increment_young_collection_count();
1910 } else {
1911 _trace_young_gen_time_data.increment_mixed_collection_count();
1912 }
1913
1914 // The young list is laid with the survivor regions from the previous
1915 // pause are appended to the RHS of the young list, i.e.
1916 // [Newly Young Regions ++ Survivors from last pause].
1917
1918 uint survivor_region_length = young_list->survivor_length();
1919 uint eden_region_length = young_list->eden_length();
1920 init_cset_region_lengths(eden_region_length, survivor_region_length);
1921
1922 HeapRegion* hr = young_list->first_survivor_region();
1923 while (hr != NULL) {
1924 assert(hr->is_survivor(), "badly formed young list");
1925 // There is a convention that all the young regions in the CSet
1926 // are tagged as "eden", so we do this for the survivors here. We
1927 // use the special set_eden_pre_gc() as it doesn't check that the
1928 // region is free (which is not the case here).
1929 hr->set_eden_pre_gc();
1930 hr = hr->get_next_young_region();
1931 }
1932
1933 // Clear the fields that point to the survivor list - they are all young now.
1934 young_list->clear_survivors();
1935
1936 _collection_set = _inc_cset_head;
1937 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
1938 time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
1939 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
1940
1941 ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
1942 "add young regions to CSet",
1943 ergo_format_region("eden")
1944 ergo_format_region("survivors")
1945 ergo_format_ms("predicted young region time"),
1946 eden_region_length, survivor_region_length,
1947 _inc_cset_predicted_elapsed_time_ms);
1948
1949 // The number of recorded young regions is the incremental
1950 // collection set's current size
1951 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
1952
1953 double young_end_time_sec = os::elapsedTime();
1954 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
1955
1956 // Set the start of the non-young choice time.
1957 double non_young_start_time_sec = young_end_time_sec;
1958
1959 if (!collector_state()->gcs_are_young()) {
1960 CollectionSetChooser* cset_chooser = _collectionSetChooser;
1961 cset_chooser->verify();
1962 const uint min_old_cset_length = calc_min_old_cset_length();
1963 const uint max_old_cset_length = calc_max_old_cset_length();
1964
1965 uint expensive_region_num = 0;
1966 bool check_time_remaining = adaptive_young_list_length();
1967
1968 HeapRegion* hr = cset_chooser->peek();
1969 while (hr != NULL) {
1970 if (old_cset_region_length() >= max_old_cset_length) {
1971 // Added maximum number of old regions to the CSet.
1972 ergo_verbose2(ErgoCSetConstruction,
1973 "finish adding old regions to CSet",
1974 ergo_format_reason("old CSet region num reached max")
1975 ergo_format_region("old")
1976 ergo_format_region("max"),
1977 old_cset_region_length(), max_old_cset_length);
1978 break;
1979 }
1980
1981
1982 // Stop adding regions if the remaining reclaimable space is
1983 // not above G1HeapWastePercent.
1984 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1985 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1986 double threshold = (double) G1HeapWastePercent;
1987 if (reclaimable_perc <= threshold) {
1988 // We've added enough old regions that the amount of uncollected
1989 // reclaimable space is at or below the waste threshold. Stop
1990 // adding old regions to the CSet.
1991 ergo_verbose5(ErgoCSetConstruction,
1992 "finish adding old regions to CSet",
1993 ergo_format_reason("reclaimable percentage not over threshold")
1994 ergo_format_region("old")
1995 ergo_format_region("max")
1996 ergo_format_byte_perc("reclaimable")
1997 ergo_format_perc("threshold"),
1998 old_cset_region_length(),
1999 max_old_cset_length,
2000 reclaimable_bytes,
2001 reclaimable_perc, threshold);
2002 break;
2003 }
2004
2005 double predicted_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
2006 if (check_time_remaining) {
2007 if (predicted_time_ms > time_remaining_ms) {
2008 // Too expensive for the current CSet.
2009
2010 if (old_cset_region_length() >= min_old_cset_length) {
2011 // We have added the minimum number of old regions to the CSet,
2012 // we are done with this CSet.
2013 ergo_verbose4(ErgoCSetConstruction,
2014 "finish adding old regions to CSet",
2015 ergo_format_reason("predicted time is too high")
2016 ergo_format_ms("predicted time")
2017 ergo_format_ms("remaining time")
2018 ergo_format_region("old")
2019 ergo_format_region("min"),
2020 predicted_time_ms, time_remaining_ms,
2021 old_cset_region_length(), min_old_cset_length);
2022 break;
2023 }
2024
2025 // We'll add it anyway given that we haven't reached the
2026 // minimum number of old regions.
2027 expensive_region_num += 1;
2028 }
2029 } else {
2030 if (old_cset_region_length() >= min_old_cset_length) {
2031 // In the non-auto-tuning case, we'll finish adding regions
2032 // to the CSet if we reach the minimum.
2033 ergo_verbose2(ErgoCSetConstruction,
2034 "finish adding old regions to CSet",
2035 ergo_format_reason("old CSet region num reached min")
2036 ergo_format_region("old")
2037 ergo_format_region("min"),
2038 old_cset_region_length(), min_old_cset_length);
2039 break;
2040 }
2041 }
2042
2043 // We will add this region to the CSet.
2044 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2045 predicted_pause_time_ms += predicted_time_ms;
2046 cset_chooser->remove_and_move_to_next(hr);
2047 _g1->old_set_remove(hr);
2048 add_old_region_to_cset(hr);
2049
2050 hr = cset_chooser->peek();
2051 }
2052 if (hr == NULL) {
2053 ergo_verbose0(ErgoCSetConstruction,
2054 "finish adding old regions to CSet",
2055 ergo_format_reason("candidate old regions not available"));
2056 }
2057
2058 if (expensive_region_num > 0) {
2059 // We print the information once here at the end, predicated on
2060 // whether we added any apparently expensive regions or not, to
2061 // avoid generating output per region.
2062 ergo_verbose4(ErgoCSetConstruction,
2063 "added expensive regions to CSet",
2064 ergo_format_reason("old CSet region num not reached min")
2065 ergo_format_region("old")
2066 ergo_format_region("expensive")
2067 ergo_format_region("min")
2068 ergo_format_ms("remaining time"),
2069 old_cset_region_length(),
2070 expensive_region_num,
2071 min_old_cset_length,
2072 time_remaining_ms);
2073 }
2074
2075 cset_chooser->verify();
2076 }
2077
2078 stop_incremental_cset_building();
2079
2080 ergo_verbose5(ErgoCSetConstruction,
2081 "finish choosing CSet",
2082 ergo_format_region("eden")
2083 ergo_format_region("survivors")
2084 ergo_format_region("old")
2085 ergo_format_ms("predicted pause time")
2086 ergo_format_ms("target pause time"),
2087 eden_region_length, survivor_region_length,
2088 old_cset_region_length(),
2089 predicted_pause_time_ms, target_pause_time_ms);
2090
2091 double non_young_end_time_sec = os::elapsedTime();
2092 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2093 }
2094
2095 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) {
2096 if(TraceYoungGenTime) {
2097 _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2098 }
2099 }
2100
2101 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) {
2102 if(TraceYoungGenTime) {
2103 _all_yield_times_ms.add(yield_time_ms);
2104 }
2105 }
2106
2107 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2108 if(TraceYoungGenTime) {
2109 _total.add(pause_time_ms);
2110 _other.add(pause_time_ms - phase_times->accounted_time_ms());
2111 _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2112 _parallel.add(phase_times->cur_collection_par_time_ms());
2113 _ext_root_scan.add(phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan));
2114 _satb_filtering.add(phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering));
2115 _update_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS));
2116 _scan_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::ScanRS));
2117 _obj_copy.add(phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy));
2118 _termination.add(phase_times->average_time_ms(G1GCPhaseTimes::Termination));
2119
2120 double parallel_known_time = phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan) +
2121 phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering) +
2122 phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS) +
2123 phase_times->average_time_ms(G1GCPhaseTimes::ScanRS) +
2124 phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy) +
2125 phase_times->average_time_ms(G1GCPhaseTimes::Termination);
2126
2127 double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2128 _parallel_other.add(parallel_other_time);
2129 _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2130 }
2131 }
2132
2133 void TraceYoungGenTimeData::increment_young_collection_count() {
2134 if(TraceYoungGenTime) {
2135 ++_young_pause_num;
2136 }
2137 }
2138
2139 void TraceYoungGenTimeData::increment_mixed_collection_count() {
2140 if(TraceYoungGenTime) {
2141 ++_mixed_pause_num;
2142 }
2143 }
2144
2145 void TraceYoungGenTimeData::print_summary(const char* str,
2146 const NumberSeq* seq) const {
2147 double sum = seq->sum();
2148 gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2149 str, sum / 1000.0, seq->avg());
2150 }
2151
2152 void TraceYoungGenTimeData::print_summary_sd(const char* str,
2153 const NumberSeq* seq) const {
2154 print_summary(str, seq);
2155 gclog_or_tty->print_cr("%45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2156 "(num", seq->num(), seq->sd(), seq->maximum());
2157 }
2158
2159 void TraceYoungGenTimeData::print() const {
2160 if (!TraceYoungGenTime) {
2161 return;
2162 }
2163
2164 gclog_or_tty->print_cr("ALL PAUSES");
2165 print_summary_sd(" Total", &_total);
2166 gclog_or_tty->cr();
2167 gclog_or_tty->cr();
2168 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num);
2169 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num);
2170 gclog_or_tty->cr();
2171
2172 gclog_or_tty->print_cr("EVACUATION PAUSES");
2173
2174 if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2175 gclog_or_tty->print_cr("none");
2176 } else {
2177 print_summary_sd(" Evacuation Pauses", &_total);
2178 print_summary(" Root Region Scan Wait", &_root_region_scan_wait);
2179 print_summary(" Parallel Time", &_parallel);
2180 print_summary(" Ext Root Scanning", &_ext_root_scan);
2181 print_summary(" SATB Filtering", &_satb_filtering);
2182 print_summary(" Update RS", &_update_rs);
2183 print_summary(" Scan RS", &_scan_rs);
2184 print_summary(" Object Copy", &_obj_copy);
2185 print_summary(" Termination", &_termination);
2186 print_summary(" Parallel Other", &_parallel_other);
2187 print_summary(" Clear CT", &_clear_ct);
2188 print_summary(" Other", &_other);
2189 }
2190 gclog_or_tty->cr();
2191
2192 gclog_or_tty->print_cr("MISC");
2193 print_summary_sd(" Stop World", &_all_stop_world_times_ms);
2194 print_summary_sd(" Yields", &_all_yield_times_ms);
2195 }
2196
2197 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) {
2198 if (TraceOldGenTime) {
2199 _all_full_gc_times.add(full_gc_time_ms);
2200 }
2201 }
2202
2203 void TraceOldGenTimeData::print() const {
2204 if (!TraceOldGenTime) {
2205 return;
2206 }
2207
2208 if (_all_full_gc_times.num() > 0) {
2209 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2210 _all_full_gc_times.num(),
2211 _all_full_gc_times.sum() / 1000.0);
2212 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2213 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2214 _all_full_gc_times.sd(),
2215 _all_full_gc_times.maximum());
2216 }
2217 }