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