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_implementation/g1/concurrentG1Refine.hpp"
27 #include "gc_implementation/g1/concurrentMark.hpp"
28 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
30 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
31 #include "gc_implementation/g1/g1ErgoVerbose.hpp"
32 #include "gc_implementation/g1/g1GCPhaseTimes.hpp"
33 #include "gc_implementation/g1/g1Log.hpp"
34 #include "gc_implementation/g1/heapRegionRemSet.hpp"
35 #include "gc_implementation/shared/gcPolicyCounters.hpp"
36 #include "runtime/arguments.hpp"
37 #include "runtime/java.hpp"
38 #include "runtime/mutexLocker.hpp"
39 #include "utilities/debug.hpp"
40
41 // Different defaults for different number of GC threads
42 // They were chosen by running GCOld and SPECjbb on debris with different
43 // numbers of GC threads and choosing them based on the results
44
45 // all the same
46 static double rs_length_diff_defaults[] = {
47 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
48 };
49
50 static double cost_per_card_ms_defaults[] = {
51 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
52 };
53
54 // all the same
55 static double young_cards_per_entry_ratio_defaults[] = {
56 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
57 };
58
59 static double cost_per_entry_ms_defaults[] = {
60 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
61 };
62
63 static double cost_per_byte_ms_defaults[] = {
64 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
65 };
66
67 // these should be pretty consistent
68 static double constant_other_time_ms_defaults[] = {
69 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
70 };
71
72
73 static double young_other_cost_per_region_ms_defaults[] = {
74 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
75 };
76
77 static double non_young_other_cost_per_region_ms_defaults[] = {
78 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
79 };
80
81 G1CollectorPolicy::G1CollectorPolicy() :
82 _parallel_gc_threads(ParallelGCThreads),
83
84 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
85 _stop_world_start(0.0),
86
87 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
88 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
89
90 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
91 _prev_collection_pause_end_ms(0.0),
92 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
93 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
94 _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
95 _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
96 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
97 _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
98 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
99 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
100 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
101 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
102 _non_young_other_cost_per_region_ms_seq(
103 new TruncatedSeq(TruncatedSeqLength)),
104
105 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
106 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
107
108 _pause_time_target_ms((double) MaxGCPauseMillis),
109
110 _gcs_are_young(true),
111
112 _during_marking(false),
113 _in_marking_window(false),
114 _in_marking_window_im(false),
115
116 _recent_prev_end_times_for_all_gcs_sec(
117 new TruncatedSeq(NumPrevPausesForHeuristics)),
118
119 _recent_avg_pause_time_ratio(0.0),
120
121 _initiate_conc_mark_if_possible(false),
122 _during_initial_mark_pause(false),
123 _last_young_gc(false),
124 _last_gc_was_young(false),
125
126 _eden_used_bytes_before_gc(0),
127 _survivor_used_bytes_before_gc(0),
128 _heap_used_bytes_before_gc(0),
129 _metaspace_used_bytes_before_gc(0),
130 _eden_capacity_bytes_before_gc(0),
131 _heap_capacity_bytes_before_gc(0),
132
133 _eden_cset_region_length(0),
134 _survivor_cset_region_length(0),
135 _old_cset_region_length(0),
136
137 _sigma(G1ConfidencePercent / 100.0),
138
139 _collection_set(NULL),
140 _collection_set_bytes_used_before(0),
141
142 // Incremental CSet attributes
143 _inc_cset_build_state(Inactive),
144 _inc_cset_head(NULL),
145 _inc_cset_tail(NULL),
146 _inc_cset_bytes_used_before(0),
147 _inc_cset_max_finger(NULL),
148 _inc_cset_recorded_rs_lengths(0),
149 _inc_cset_recorded_rs_lengths_diffs(0),
150 _inc_cset_predicted_elapsed_time_ms(0.0),
151 _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
152
153 // add here any more surv rate groups
154 _recorded_survivor_regions(0),
155 _recorded_survivor_head(NULL),
156 _recorded_survivor_tail(NULL),
157 _survivors_age_table(true),
158
159 _gc_overhead_perc(0.0) {
160
161 // SurvRateGroups below must be initialized after '_sigma' because they
162 // indirectly access '_sigma' through this object passed to their constructor.
163 _short_lived_surv_rate_group =
164 new SurvRateGroup(this, "Short Lived", G1YoungSurvRateNumRegionsSummary);
165 _survivor_surv_rate_group =
166 new SurvRateGroup(this, "Survivor", G1YoungSurvRateNumRegionsSummary);
167
168 // Set up the region size and associated fields. Given that the
169 // policy is created before the heap, we have to set this up here,
170 // so it's done as soon as possible.
171
172 // It would have been natural to pass initial_heap_byte_size() and
173 // max_heap_byte_size() to setup_heap_region_size() but those have
174 // not been set up at this point since they should be aligned with
175 // the region size. So, there is a circular dependency here. We base
176 // the region size on the heap size, but the heap size should be
177 // aligned with the region size. To get around this we use the
178 // unaligned values for the heap.
179 HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
180 HeapRegionRemSet::setup_remset_size();
181
182 G1ErgoVerbose::initialize();
183 if (PrintAdaptiveSizePolicy) {
184 // Currently, we only use a single switch for all the heuristics.
185 G1ErgoVerbose::set_enabled(true);
186 // Given that we don't currently have a verboseness level
187 // parameter, we'll hardcode this to high. This can be easily
188 // changed in the future.
189 G1ErgoVerbose::set_level(ErgoHigh);
190 } else {
191 G1ErgoVerbose::set_enabled(false);
192 }
193
194 // Verify PLAB sizes
195 const size_t region_size = HeapRegion::GrainWords;
196 if (YoungPLABSize > region_size || OldPLABSize > region_size) {
197 char buffer[128];
198 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT,
199 OldPLABSize > region_size ? "Old" : "Young", region_size);
200 vm_exit_during_initialization(buffer);
201 }
202
203 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
204 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
205
206 _phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
207
208 int index = MIN2(_parallel_gc_threads - 1, 7);
209
210 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
211 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
212 _young_cards_per_entry_ratio_seq->add(
213 young_cards_per_entry_ratio_defaults[index]);
214 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
215 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
216 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
217 _young_other_cost_per_region_ms_seq->add(
218 young_other_cost_per_region_ms_defaults[index]);
219 _non_young_other_cost_per_region_ms_seq->add(
220 non_young_other_cost_per_region_ms_defaults[index]);
221
222 // Below, we might need to calculate the pause time target based on
223 // the pause interval. When we do so we are going to give G1 maximum
224 // flexibility and allow it to do pauses when it needs to. So, we'll
225 // arrange that the pause interval to be pause time target + 1 to
226 // ensure that a) the pause time target is maximized with respect to
227 // the pause interval and b) we maintain the invariant that pause
228 // time target < pause interval. If the user does not want this
229 // maximum flexibility, they will have to set the pause interval
230 // explicitly.
231
232 // First make sure that, if either parameter is set, its value is
233 // reasonable.
234 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
235 if (MaxGCPauseMillis < 1) {
236 vm_exit_during_initialization("MaxGCPauseMillis should be "
237 "greater than 0");
238 }
239 }
240 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
241 if (GCPauseIntervalMillis < 1) {
242 vm_exit_during_initialization("GCPauseIntervalMillis should be "
243 "greater than 0");
244 }
245 }
246
247 // Then, if the pause time target parameter was not set, set it to
248 // the default value.
249 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
250 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
251 // The default pause time target in G1 is 200ms
252 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
253 } else {
254 // We do not allow the pause interval to be set without the
255 // pause time target
256 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
257 "without setting MaxGCPauseMillis");
258 }
259 }
260
261 // Then, if the interval parameter was not set, set it according to
262 // the pause time target (this will also deal with the case when the
263 // pause time target is the default value).
264 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
265 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
266 }
267
268 // Finally, make sure that the two parameters are consistent.
269 if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
270 char buffer[256];
271 jio_snprintf(buffer, 256,
272 "MaxGCPauseMillis (%u) should be less than "
273 "GCPauseIntervalMillis (%u)",
274 MaxGCPauseMillis, GCPauseIntervalMillis);
275 vm_exit_during_initialization(buffer);
276 }
277
278 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
279 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
280 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
281
282 // start conservatively (around 50ms is about right)
283 _concurrent_mark_remark_times_ms->add(0.05);
284 _concurrent_mark_cleanup_times_ms->add(0.20);
285 _tenuring_threshold = MaxTenuringThreshold;
286 // _max_survivor_regions will be calculated by
287 // update_young_list_target_length() during initialization.
288 _max_survivor_regions = 0;
289
290 assert(GCTimeRatio > 0,
291 "we should have set it to a default value set_g1_gc_flags() "
292 "if a user set it to 0");
293 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
294
295 uintx reserve_perc = G1ReservePercent;
296 // Put an artificial ceiling on this so that it's not set to a silly value.
297 if (reserve_perc > 50) {
298 reserve_perc = 50;
299 warning("G1ReservePercent is set to a value that is too large, "
300 "it's been updated to " UINTX_FORMAT, reserve_perc);
301 }
302 _reserve_factor = (double) reserve_perc / 100.0;
303 // This will be set when the heap is expanded
304 // for the first time during initialization.
305 _reserve_regions = 0;
306
307 _collectionSetChooser = new CollectionSetChooser();
308 }
309
310 void G1CollectorPolicy::initialize_alignments() {
311 _space_alignment = HeapRegion::GrainBytes;
312 size_t card_table_alignment = GenRemSet::max_alignment_constraint();
313 size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
314 _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
315 }
316
317 void G1CollectorPolicy::initialize_flags() {
318 if (G1HeapRegionSize != HeapRegion::GrainBytes) {
319 FLAG_SET_ERGO(size_t, G1HeapRegionSize, HeapRegion::GrainBytes);
320 }
321
322 if (SurvivorRatio < 1) {
323 vm_exit_during_initialization("Invalid survivor ratio specified");
324 }
325 CollectorPolicy::initialize_flags();
326 _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
327 }
328
329 void G1CollectorPolicy::post_heap_initialize() {
330 uintx max_regions = G1CollectedHeap::heap()->max_regions();
331 size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
332 if (max_young_size != MaxNewSize) {
333 FLAG_SET_ERGO(size_t, MaxNewSize, max_young_size);
334 }
335 }
336
337 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
338 _min_desired_young_length(0), _max_desired_young_length(0) {
339 if (FLAG_IS_CMDLINE(NewRatio)) {
340 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
341 warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
342 } else {
343 _sizer_kind = SizerNewRatio;
344 _adaptive_size = false;
345 return;
346 }
347 }
348
349 if (NewSize > MaxNewSize) {
350 if (FLAG_IS_CMDLINE(MaxNewSize)) {
351 warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
352 "A new max generation size of " SIZE_FORMAT "k will be used.",
353 NewSize/K, MaxNewSize/K, NewSize/K);
354 }
355 MaxNewSize = NewSize;
356 }
357
358 if (FLAG_IS_CMDLINE(NewSize)) {
359 _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
360 1U);
361 if (FLAG_IS_CMDLINE(MaxNewSize)) {
362 _max_desired_young_length =
363 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
364 1U);
365 _sizer_kind = SizerMaxAndNewSize;
366 _adaptive_size = _min_desired_young_length == _max_desired_young_length;
367 } else {
368 _sizer_kind = SizerNewSizeOnly;
369 }
370 } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
371 _max_desired_young_length =
372 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
373 1U);
374 _sizer_kind = SizerMaxNewSizeOnly;
375 }
376 }
377
378 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
379 uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
380 return MAX2(1U, default_value);
381 }
382
383 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
384 uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
385 return MAX2(1U, default_value);
386 }
387
388 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
389 assert(number_of_heap_regions > 0, "Heap must be initialized");
390
391 switch (_sizer_kind) {
392 case SizerDefaults:
393 *min_young_length = calculate_default_min_length(number_of_heap_regions);
394 *max_young_length = calculate_default_max_length(number_of_heap_regions);
395 break;
396 case SizerNewSizeOnly:
397 *max_young_length = calculate_default_max_length(number_of_heap_regions);
398 *max_young_length = MAX2(*min_young_length, *max_young_length);
399 break;
400 case SizerMaxNewSizeOnly:
401 *min_young_length = calculate_default_min_length(number_of_heap_regions);
402 *min_young_length = MIN2(*min_young_length, *max_young_length);
403 break;
404 case SizerMaxAndNewSize:
405 // Do nothing. Values set on the command line, don't update them at runtime.
406 break;
407 case SizerNewRatio:
408 *min_young_length = number_of_heap_regions / (NewRatio + 1);
409 *max_young_length = *min_young_length;
410 break;
411 default:
412 ShouldNotReachHere();
413 }
414
415 assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
416 }
417
418 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
419 // We need to pass the desired values because recalculation may not update these
420 // values in some cases.
421 uint temp = _min_desired_young_length;
422 uint result = _max_desired_young_length;
423 recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
424 return result;
425 }
426
427 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
428 recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
429 &_max_desired_young_length);
430 }
431
432 void G1CollectorPolicy::init() {
433 // Set aside an initial future to_space.
434 _g1 = G1CollectedHeap::heap();
435
436 assert(Heap_lock->owned_by_self(), "Locking discipline.");
437
438 initialize_gc_policy_counters();
439
440 if (adaptive_young_list_length()) {
441 _young_list_fixed_length = 0;
442 } else {
443 _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
444 }
445 _free_regions_at_end_of_collection = _g1->num_free_regions();
446 update_young_list_target_length();
447
448 // We may immediately start allocating regions and placing them on the
449 // collection set list. Initialize the per-collection set info
450 start_incremental_cset_building();
451 }
452
453 // Create the jstat counters for the policy.
454 void G1CollectorPolicy::initialize_gc_policy_counters() {
455 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
456 }
457
458 bool G1CollectorPolicy::predict_will_fit(uint young_length,
459 double base_time_ms,
460 uint base_free_regions,
461 double target_pause_time_ms) {
462 if (young_length >= base_free_regions) {
463 // end condition 1: not enough space for the young regions
464 return false;
465 }
466
467 double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
468 size_t bytes_to_copy =
469 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
470 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
471 double young_other_time_ms = predict_young_other_time_ms(young_length);
472 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
473 if (pause_time_ms > target_pause_time_ms) {
474 // end condition 2: prediction is over the target pause time
475 return false;
476 }
477
478 size_t free_bytes =
479 (base_free_regions - young_length) * HeapRegion::GrainBytes;
480 if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
481 // end condition 3: out-of-space (conservatively!)
482 return false;
483 }
484
485 // success!
486 return true;
487 }
488
489 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
490 // re-calculate the necessary reserve
491 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
492 // We use ceiling so that if reserve_regions_d is > 0.0 (but
493 // smaller than 1.0) we'll get 1.
494 _reserve_regions = (uint) ceil(reserve_regions_d);
495
496 _young_gen_sizer->heap_size_changed(new_number_of_regions);
497 }
498
499 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
500 uint base_min_length) {
501 uint desired_min_length = 0;
502 if (adaptive_young_list_length()) {
503 if (_alloc_rate_ms_seq->num() > 3) {
504 double now_sec = os::elapsedTime();
505 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
506 double alloc_rate_ms = predict_alloc_rate_ms();
507 desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
508 } else {
509 // otherwise we don't have enough info to make the prediction
510 }
511 }
512 desired_min_length += base_min_length;
513 // make sure we don't go below any user-defined minimum bound
514 return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
515 }
516
517 uint G1CollectorPolicy::calculate_young_list_desired_max_length() {
518 // Here, we might want to also take into account any additional
519 // constraints (i.e., user-defined minimum bound). Currently, we
520 // effectively don't set this bound.
521 return _young_gen_sizer->max_desired_young_length();
522 }
523
524 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
525 if (rs_lengths == (size_t) -1) {
526 // if it's set to the default value (-1), we should predict it;
527 // otherwise, use the given value.
528 rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
529 }
530
531 // Calculate the absolute and desired min bounds.
532
533 // This is how many young regions we already have (currently: the survivors).
534 uint base_min_length = recorded_survivor_regions();
535 uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
536 // This is the absolute minimum young length. Ensure that we
537 // will at least have one eden region available for allocation.
538 uint absolute_min_length = base_min_length + MAX2(_g1->young_list()->eden_length(), (uint)1);
539 // If we shrank the young list target it should not shrink below the current size.
540 desired_min_length = MAX2(desired_min_length, absolute_min_length);
541 // Calculate the absolute and desired max bounds.
542
543 // We will try our best not to "eat" into the reserve.
544 uint absolute_max_length = 0;
545 if (_free_regions_at_end_of_collection > _reserve_regions) {
546 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
547 }
548 uint desired_max_length = calculate_young_list_desired_max_length();
549 if (desired_max_length > absolute_max_length) {
550 desired_max_length = absolute_max_length;
551 }
552
553 uint young_list_target_length = 0;
554 if (adaptive_young_list_length()) {
555 if (gcs_are_young()) {
556 young_list_target_length =
557 calculate_young_list_target_length(rs_lengths,
558 base_min_length,
559 desired_min_length,
560 desired_max_length);
561 _rs_lengths_prediction = rs_lengths;
562 } else {
563 // Don't calculate anything and let the code below bound it to
564 // the desired_min_length, i.e., do the next GC as soon as
565 // possible to maximize how many old regions we can add to it.
566 }
567 } else {
568 // The user asked for a fixed young gen so we'll fix the young gen
569 // whether the next GC is young or mixed.
570 young_list_target_length = _young_list_fixed_length;
571 }
572
573 // Make sure we don't go over the desired max length, nor under the
574 // desired min length. In case they clash, desired_min_length wins
575 // which is why that test is second.
576 if (young_list_target_length > desired_max_length) {
577 young_list_target_length = desired_max_length;
578 }
579 if (young_list_target_length < desired_min_length) {
580 young_list_target_length = desired_min_length;
581 }
582
583 assert(young_list_target_length > recorded_survivor_regions(),
584 "we should be able to allocate at least one eden region");
585 assert(young_list_target_length >= absolute_min_length, "post-condition");
586 _young_list_target_length = young_list_target_length;
587
588 update_max_gc_locker_expansion();
589 }
590
591 uint
592 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
593 uint base_min_length,
594 uint desired_min_length,
595 uint desired_max_length) {
596 assert(adaptive_young_list_length(), "pre-condition");
597 assert(gcs_are_young(), "only call this for young GCs");
598
599 // In case some edge-condition makes the desired max length too small...
600 if (desired_max_length <= desired_min_length) {
601 return desired_min_length;
602 }
603
604 // We'll adjust min_young_length and max_young_length not to include
605 // the already allocated young regions (i.e., so they reflect the
606 // min and max eden regions we'll allocate). The base_min_length
607 // will be reflected in the predictions by the
608 // survivor_regions_evac_time prediction.
609 assert(desired_min_length > base_min_length, "invariant");
610 uint min_young_length = desired_min_length - base_min_length;
611 assert(desired_max_length > base_min_length, "invariant");
612 uint max_young_length = desired_max_length - base_min_length;
613
614 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
615 double survivor_regions_evac_time = predict_survivor_regions_evac_time();
616 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
617 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
618 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
619 double base_time_ms =
620 predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
621 survivor_regions_evac_time;
622 uint available_free_regions = _free_regions_at_end_of_collection;
623 uint base_free_regions = 0;
624 if (available_free_regions > _reserve_regions) {
625 base_free_regions = available_free_regions - _reserve_regions;
626 }
627
628 // Here, we will make sure that the shortest young length that
629 // makes sense fits within the target pause time.
630
631 if (predict_will_fit(min_young_length, base_time_ms,
632 base_free_regions, target_pause_time_ms)) {
633 // The shortest young length will fit into the target pause time;
634 // we'll now check whether the absolute maximum number of young
635 // regions will fit in the target pause time. If not, we'll do
636 // a binary search between min_young_length and max_young_length.
637 if (predict_will_fit(max_young_length, base_time_ms,
638 base_free_regions, target_pause_time_ms)) {
639 // The maximum young length will fit into the target pause time.
640 // We are done so set min young length to the maximum length (as
641 // the result is assumed to be returned in min_young_length).
642 min_young_length = max_young_length;
643 } else {
644 // The maximum possible number of young regions will not fit within
645 // the target pause time so we'll search for the optimal
646 // length. The loop invariants are:
647 //
648 // min_young_length < max_young_length
649 // min_young_length is known to fit into the target pause time
650 // max_young_length is known not to fit into the target pause time
651 //
652 // Going into the loop we know the above hold as we've just
653 // checked them. Every time around the loop we check whether
654 // the middle value between min_young_length and
655 // max_young_length fits into the target pause time. If it
656 // does, it becomes the new min. If it doesn't, it becomes
657 // the new max. This way we maintain the loop invariants.
658
659 assert(min_young_length < max_young_length, "invariant");
660 uint diff = (max_young_length - min_young_length) / 2;
661 while (diff > 0) {
662 uint young_length = min_young_length + diff;
663 if (predict_will_fit(young_length, base_time_ms,
664 base_free_regions, target_pause_time_ms)) {
665 min_young_length = young_length;
666 } else {
667 max_young_length = young_length;
668 }
669 assert(min_young_length < max_young_length, "invariant");
670 diff = (max_young_length - min_young_length) / 2;
671 }
672 // The results is min_young_length which, according to the
673 // loop invariants, should fit within the target pause time.
674
675 // These are the post-conditions of the binary search above:
676 assert(min_young_length < max_young_length,
677 "otherwise we should have discovered that max_young_length "
678 "fits into the pause target and not done the binary search");
679 assert(predict_will_fit(min_young_length, base_time_ms,
680 base_free_regions, target_pause_time_ms),
681 "min_young_length, the result of the binary search, should "
682 "fit into the pause target");
683 assert(!predict_will_fit(min_young_length + 1, base_time_ms,
684 base_free_regions, target_pause_time_ms),
685 "min_young_length, the result of the binary search, should be "
686 "optimal, so no larger length should fit into the pause target");
687 }
688 } else {
689 // Even the minimum length doesn't fit into the pause time
690 // target, return it as the result nevertheless.
691 }
692 return base_min_length + min_young_length;
693 }
694
695 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
696 double survivor_regions_evac_time = 0.0;
697 for (HeapRegion * r = _recorded_survivor_head;
698 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
699 r = r->get_next_young_region()) {
700 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young());
701 }
702 return survivor_regions_evac_time;
703 }
704
705 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
706 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
707
708 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
709 if (rs_lengths > _rs_lengths_prediction) {
710 // add 10% to avoid having to recalculate often
711 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
712 update_young_list_target_length(rs_lengths_prediction);
713 }
714 }
715
716
717
718 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
719 bool is_tlab,
720 bool* gc_overhead_limit_was_exceeded) {
721 guarantee(false, "Not using this policy feature yet.");
722 return NULL;
723 }
724
725 // This method controls how a collector handles one or more
726 // of its generations being fully allocated.
727 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
728 bool is_tlab) {
729 guarantee(false, "Not using this policy feature yet.");
730 return NULL;
731 }
732
733
734 #ifndef PRODUCT
735 bool G1CollectorPolicy::verify_young_ages() {
736 HeapRegion* head = _g1->young_list()->first_region();
737 return
738 verify_young_ages(head, _short_lived_surv_rate_group);
739 // also call verify_young_ages on any additional surv rate groups
740 }
741
742 bool
743 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
744 SurvRateGroup *surv_rate_group) {
745 guarantee( surv_rate_group != NULL, "pre-condition" );
746
747 const char* name = surv_rate_group->name();
748 bool ret = true;
749 int prev_age = -1;
750
751 for (HeapRegion* curr = head;
752 curr != NULL;
753 curr = curr->get_next_young_region()) {
754 SurvRateGroup* group = curr->surv_rate_group();
755 if (group == NULL && !curr->is_survivor()) {
756 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
757 ret = false;
758 }
759
760 if (surv_rate_group == group) {
761 int age = curr->age_in_surv_rate_group();
762
763 if (age < 0) {
764 gclog_or_tty->print_cr("## %s: encountered negative age", name);
765 ret = false;
766 }
767
768 if (age <= prev_age) {
769 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
770 "(%d, %d)", name, age, prev_age);
771 ret = false;
772 }
773 prev_age = age;
774 }
775 }
776
777 return ret;
778 }
779 #endif // PRODUCT
780
781 void G1CollectorPolicy::record_full_collection_start() {
782 _full_collection_start_sec = os::elapsedTime();
783 record_heap_size_info_at_start(true /* full */);
784 // Release the future to-space so that it is available for compaction into.
785 _g1->set_full_collection();
786 }
787
788 void G1CollectorPolicy::record_full_collection_end() {
789 // Consider this like a collection pause for the purposes of allocation
790 // since last pause.
791 double end_sec = os::elapsedTime();
792 double full_gc_time_sec = end_sec - _full_collection_start_sec;
793 double full_gc_time_ms = full_gc_time_sec * 1000.0;
794
795 _trace_old_gen_time_data.record_full_collection(full_gc_time_ms);
796
797 update_recent_gc_times(end_sec, full_gc_time_ms);
798
799 _g1->clear_full_collection();
800
801 // "Nuke" the heuristics that control the young/mixed GC
802 // transitions and make sure we start with young GCs after the Full GC.
803 set_gcs_are_young(true);
804 _last_young_gc = false;
805 clear_initiate_conc_mark_if_possible();
806 clear_during_initial_mark_pause();
807 _in_marking_window = false;
808 _in_marking_window_im = false;
809
810 _short_lived_surv_rate_group->start_adding_regions();
811 // also call this on any additional surv rate groups
812
813 record_survivor_regions(0, NULL, NULL);
814
815 _free_regions_at_end_of_collection = _g1->num_free_regions();
816 // Reset survivors SurvRateGroup.
817 _survivor_surv_rate_group->reset();
818 update_young_list_target_length();
819 _collectionSetChooser->clear();
820 }
821
822 void G1CollectorPolicy::record_stop_world_start() {
823 _stop_world_start = os::elapsedTime();
824 }
825
826 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
827 // We only need to do this here as the policy will only be applied
828 // to the GC we're about to start. so, no point is calculating this
829 // every time we calculate / recalculate the target young length.
830 update_survivors_policy();
831
832 assert(_g1->used() == _g1->recalculate_used(),
833 err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
834 _g1->used(), _g1->recalculate_used()));
835
836 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
837 _trace_young_gen_time_data.record_start_collection(s_w_t_ms);
838 _stop_world_start = 0.0;
839
840 record_heap_size_info_at_start(false /* full */);
841
842 phase_times()->record_cur_collection_start_sec(start_time_sec);
843 _pending_cards = _g1->pending_card_num();
844
845 _collection_set_bytes_used_before = 0;
846 _bytes_copied_during_gc = 0;
847
848 _last_gc_was_young = false;
849
850 // do that for any other surv rate groups
851 _short_lived_surv_rate_group->stop_adding_regions();
852 _survivors_age_table.clear();
853
854 assert( verify_young_ages(), "region age verification" );
855 }
856
857 void G1CollectorPolicy::record_concurrent_mark_init_end(double
858 mark_init_elapsed_time_ms) {
859 _during_marking = true;
860 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
861 clear_during_initial_mark_pause();
862 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
863 }
864
865 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
866 _mark_remark_start_sec = os::elapsedTime();
867 _during_marking = false;
868 }
869
870 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
871 double end_time_sec = os::elapsedTime();
872 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
873 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
874 _cur_mark_stop_world_time_ms += elapsed_time_ms;
875 _prev_collection_pause_end_ms += elapsed_time_ms;
876
877 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
878 }
879
880 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
881 _mark_cleanup_start_sec = os::elapsedTime();
882 }
883
884 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
885 _last_young_gc = true;
886 _in_marking_window = false;
887 }
888
889 void G1CollectorPolicy::record_concurrent_pause() {
890 if (_stop_world_start > 0.0) {
891 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
892 _trace_young_gen_time_data.record_yield_time(yield_ms);
893 }
894 }
895
896 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
897 if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
898 return false;
899 }
900
901 size_t marking_initiating_used_threshold =
902 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
903 size_t cur_used_bytes = _g1->non_young_capacity_bytes();
904 size_t alloc_byte_size = alloc_word_size * HeapWordSize;
905
906 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
907 if (gcs_are_young() && !_last_young_gc) {
908 ergo_verbose5(ErgoConcCycles,
909 "request concurrent cycle initiation",
910 ergo_format_reason("occupancy higher than threshold")
911 ergo_format_byte("occupancy")
912 ergo_format_byte("allocation request")
913 ergo_format_byte_perc("threshold")
914 ergo_format_str("source"),
915 cur_used_bytes,
916 alloc_byte_size,
917 marking_initiating_used_threshold,
918 (double) InitiatingHeapOccupancyPercent,
919 source);
920 return true;
921 } else {
922 ergo_verbose5(ErgoConcCycles,
923 "do not request concurrent cycle initiation",
924 ergo_format_reason("still doing mixed collections")
925 ergo_format_byte("occupancy")
926 ergo_format_byte("allocation request")
927 ergo_format_byte_perc("threshold")
928 ergo_format_str("source"),
929 cur_used_bytes,
930 alloc_byte_size,
931 marking_initiating_used_threshold,
932 (double) InitiatingHeapOccupancyPercent,
933 source);
934 }
935 }
936
937 return false;
938 }
939
940 // Anything below that is considered to be zero
941 #define MIN_TIMER_GRANULARITY 0.0000001
942
943 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info) {
944 double end_time_sec = os::elapsedTime();
945 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
946 "otherwise, the subtraction below does not make sense");
947 size_t rs_size =
948 _cur_collection_pause_used_regions_at_start - cset_region_length();
949 size_t cur_used_bytes = _g1->used();
950 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
951 bool last_pause_included_initial_mark = false;
952 bool update_stats = !_g1->evacuation_failed();
953
954 #ifndef PRODUCT
955 if (G1YoungSurvRateVerbose) {
956 gclog_or_tty->cr();
957 _short_lived_surv_rate_group->print();
958 // do that for any other surv rate groups too
959 }
960 #endif // PRODUCT
961
962 last_pause_included_initial_mark = during_initial_mark_pause();
963 if (last_pause_included_initial_mark) {
964 record_concurrent_mark_init_end(0.0);
965 } else if (need_to_start_conc_mark("end of GC")) {
966 // Note: this might have already been set, if during the last
967 // pause we decided to start a cycle but at the beginning of
968 // this pause we decided to postpone it. That's OK.
969 set_initiate_conc_mark_if_possible();
970 }
971
972 _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0,
973 end_time_sec, false);
974
975 evacuation_info.set_collectionset_used_before(_collection_set_bytes_used_before);
976 evacuation_info.set_bytes_copied(_bytes_copied_during_gc);
977
978 if (update_stats) {
979 _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times());
980 // this is where we update the allocation rate of the application
981 double app_time_ms =
982 (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
983 if (app_time_ms < MIN_TIMER_GRANULARITY) {
984 // This usually happens due to the timer not having the required
985 // granularity. Some Linuxes are the usual culprits.
986 // We'll just set it to something (arbitrarily) small.
987 app_time_ms = 1.0;
988 }
989 // We maintain the invariant that all objects allocated by mutator
990 // threads will be allocated out of eden regions. So, we can use
991 // the eden region number allocated since the previous GC to
992 // calculate the application's allocate rate. The only exception
993 // to that is humongous objects that are allocated separately. But
994 // given that humongous object allocations do not really affect
995 // either the pause's duration nor when the next pause will take
996 // place we can safely ignore them here.
997 uint regions_allocated = eden_cset_region_length();
998 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
999 _alloc_rate_ms_seq->add(alloc_rate_ms);
1000
1001 double interval_ms =
1002 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1003 update_recent_gc_times(end_time_sec, pause_time_ms);
1004 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1005 if (recent_avg_pause_time_ratio() < 0.0 ||
1006 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1007 #ifndef PRODUCT
1008 // Dump info to allow post-facto debugging
1009 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1010 gclog_or_tty->print_cr("-------------------------------------------");
1011 gclog_or_tty->print_cr("Recent GC Times (ms):");
1012 _recent_gc_times_ms->dump();
1013 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1014 _recent_prev_end_times_for_all_gcs_sec->dump();
1015 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1016 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1017 // In debug mode, terminate the JVM if the user wants to debug at this point.
1018 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1019 #endif // !PRODUCT
1020 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1021 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1022 if (_recent_avg_pause_time_ratio < 0.0) {
1023 _recent_avg_pause_time_ratio = 0.0;
1024 } else {
1025 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1026 _recent_avg_pause_time_ratio = 1.0;
1027 }
1028 }
1029 }
1030
1031 bool new_in_marking_window = _in_marking_window;
1032 bool new_in_marking_window_im = false;
1033 if (last_pause_included_initial_mark) {
1034 new_in_marking_window = true;
1035 new_in_marking_window_im = true;
1036 }
1037
1038 if (_last_young_gc) {
1039 // This is supposed to to be the "last young GC" before we start
1040 // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1041
1042 if (!last_pause_included_initial_mark) {
1043 if (next_gc_should_be_mixed("start mixed GCs",
1044 "do not start mixed GCs")) {
1045 set_gcs_are_young(false);
1046 }
1047 } else {
1048 ergo_verbose0(ErgoMixedGCs,
1049 "do not start mixed GCs",
1050 ergo_format_reason("concurrent cycle is about to start"));
1051 }
1052 _last_young_gc = false;
1053 }
1054
1055 if (!_last_gc_was_young) {
1056 // This is a mixed GC. Here we decide whether to continue doing
1057 // mixed GCs or not.
1058
1059 if (!next_gc_should_be_mixed("continue mixed GCs",
1060 "do not continue mixed GCs")) {
1061 set_gcs_are_young(true);
1062 }
1063 }
1064
1065 _short_lived_surv_rate_group->start_adding_regions();
1066 // Do that for any other surv rate groups
1067
1068 if (update_stats) {
1069 double cost_per_card_ms = 0.0;
1070 if (_pending_cards > 0) {
1071 cost_per_card_ms = phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS) / (double) _pending_cards;
1072 _cost_per_card_ms_seq->add(cost_per_card_ms);
1073 }
1074
1075 size_t cards_scanned = _g1->cards_scanned();
1076
1077 double cost_per_entry_ms = 0.0;
1078 if (cards_scanned > 10) {
1079 cost_per_entry_ms = phase_times()->average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
1080 if (_last_gc_was_young) {
1081 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1082 } else {
1083 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1084 }
1085 }
1086
1087 if (_max_rs_lengths > 0) {
1088 double cards_per_entry_ratio =
1089 (double) cards_scanned / (double) _max_rs_lengths;
1090 if (_last_gc_was_young) {
1091 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1092 } else {
1093 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1094 }
1095 }
1096
1097 // This is defensive. For a while _max_rs_lengths could get
1098 // smaller than _recorded_rs_lengths which was causing
1099 // rs_length_diff to get very large and mess up the RSet length
1100 // predictions. The reason was unsafe concurrent updates to the
1101 // _inc_cset_recorded_rs_lengths field which the code below guards
1102 // against (see CR 7118202). This bug has now been fixed (see CR
1103 // 7119027). However, I'm still worried that
1104 // _inc_cset_recorded_rs_lengths might still end up somewhat
1105 // inaccurate. The concurrent refinement thread calculates an
1106 // RSet's length concurrently with other CR threads updating it
1107 // which might cause it to calculate the length incorrectly (if,
1108 // say, it's in mid-coarsening). So I'll leave in the defensive
1109 // conditional below just in case.
1110 size_t rs_length_diff = 0;
1111 if (_max_rs_lengths > _recorded_rs_lengths) {
1112 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1113 }
1114 _rs_length_diff_seq->add((double) rs_length_diff);
1115
1116 size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1117 size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1118 double cost_per_byte_ms = 0.0;
1119
1120 if (copied_bytes > 0) {
1121 cost_per_byte_ms = phase_times()->average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
1122 if (_in_marking_window) {
1123 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1124 } else {
1125 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1126 }
1127 }
1128
1129 double all_other_time_ms = pause_time_ms -
1130 (phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS) + phase_times()->average_time_ms(G1GCPhaseTimes::ScanRS) +
1131 phase_times()->average_time_ms(G1GCPhaseTimes::ObjCopy) + phase_times()->average_time_ms(G1GCPhaseTimes::Termination));
1132
1133 double young_other_time_ms = 0.0;
1134 if (young_cset_region_length() > 0) {
1135 young_other_time_ms =
1136 phase_times()->young_cset_choice_time_ms() +
1137 phase_times()->young_free_cset_time_ms();
1138 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1139 (double) young_cset_region_length());
1140 }
1141 double non_young_other_time_ms = 0.0;
1142 if (old_cset_region_length() > 0) {
1143 non_young_other_time_ms =
1144 phase_times()->non_young_cset_choice_time_ms() +
1145 phase_times()->non_young_free_cset_time_ms();
1146
1147 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1148 (double) old_cset_region_length());
1149 }
1150
1151 double constant_other_time_ms = all_other_time_ms -
1152 (young_other_time_ms + non_young_other_time_ms);
1153 _constant_other_time_ms_seq->add(constant_other_time_ms);
1154
1155 double survival_ratio = 0.0;
1156 if (_collection_set_bytes_used_before > 0) {
1157 survival_ratio = (double) _bytes_copied_during_gc /
1158 (double) _collection_set_bytes_used_before;
1159 }
1160
1161 _pending_cards_seq->add((double) _pending_cards);
1162 _rs_lengths_seq->add((double) _max_rs_lengths);
1163 }
1164
1165 _in_marking_window = new_in_marking_window;
1166 _in_marking_window_im = new_in_marking_window_im;
1167 _free_regions_at_end_of_collection = _g1->num_free_regions();
1168 update_young_list_target_length();
1169
1170 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1171 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1172 adjust_concurrent_refinement(phase_times()->average_time_ms(G1GCPhaseTimes::UpdateRS),
1173 phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS), update_rs_time_goal_ms);
1174
1175 _collectionSetChooser->verify();
1176 }
1177
1178 #define EXT_SIZE_FORMAT "%.1f%s"
1179 #define EXT_SIZE_PARAMS(bytes) \
1180 byte_size_in_proper_unit((double)(bytes)), \
1181 proper_unit_for_byte_size((bytes))
1182
1183 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1184 YoungList* young_list = _g1->young_list();
1185 _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1186 _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1187 _heap_capacity_bytes_before_gc = _g1->capacity();
1188 _heap_used_bytes_before_gc = _g1->used();
1189 _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1190
1191 _eden_capacity_bytes_before_gc =
1192 (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1193
1194 if (full) {
1195 _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1196 }
1197 }
1198
1199 void G1CollectorPolicy::print_heap_transition(size_t bytes_before) {
1200 size_t bytes_after = _g1->used();
1201 size_t capacity = _g1->capacity();
1202
1203 gclog_or_tty->print(" " SIZE_FORMAT "%s->" SIZE_FORMAT "%s(" SIZE_FORMAT "%s)",
1204 byte_size_in_proper_unit(bytes_before),
1205 proper_unit_for_byte_size(bytes_before),
1206 byte_size_in_proper_unit(bytes_after),
1207 proper_unit_for_byte_size(bytes_after),
1208 byte_size_in_proper_unit(capacity),
1209 proper_unit_for_byte_size(capacity));
1210 }
1211
1212 void G1CollectorPolicy::print_heap_transition() {
1213 print_heap_transition(_heap_used_bytes_before_gc);
1214 }
1215
1216 void G1CollectorPolicy::print_detailed_heap_transition(bool full) {
1217 YoungList* young_list = _g1->young_list();
1218
1219 size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1220 size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1221 size_t heap_used_bytes_after_gc = _g1->used();
1222
1223 size_t heap_capacity_bytes_after_gc = _g1->capacity();
1224 size_t eden_capacity_bytes_after_gc =
1225 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1226
1227 gclog_or_tty->print(
1228 " [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
1229 "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1230 "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
1231 EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
1232 EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1233 EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1234 EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1235 EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1236 EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1237 EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1238 EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1239 EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1240 EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1241 EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1242
1243 if (full) {
1244 MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1245 }
1246
1247 gclog_or_tty->cr();
1248 }
1249
1250 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1251 double update_rs_processed_buffers,
1252 double goal_ms) {
1253 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1254 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1255
1256 if (G1UseAdaptiveConcRefinement) {
1257 const int k_gy = 3, k_gr = 6;
1258 const double inc_k = 1.1, dec_k = 0.9;
1259
1260 int g = cg1r->green_zone();
1261 if (update_rs_time > goal_ms) {
1262 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1263 } else {
1264 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1265 g = (int)MAX2(g * inc_k, g + 1.0);
1266 }
1267 }
1268 // Change the refinement threads params
1269 cg1r->set_green_zone(g);
1270 cg1r->set_yellow_zone(g * k_gy);
1271 cg1r->set_red_zone(g * k_gr);
1272 cg1r->reinitialize_threads();
1273
1274 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1275 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1276 cg1r->yellow_zone());
1277 // Change the barrier params
1278 dcqs.set_process_completed_threshold(processing_threshold);
1279 dcqs.set_max_completed_queue(cg1r->red_zone());
1280 }
1281
1282 int curr_queue_size = dcqs.completed_buffers_num();
1283 if (curr_queue_size >= cg1r->yellow_zone()) {
1284 dcqs.set_completed_queue_padding(curr_queue_size);
1285 } else {
1286 dcqs.set_completed_queue_padding(0);
1287 }
1288 dcqs.notify_if_necessary();
1289 }
1290
1291 double
1292 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1293 size_t scanned_cards) {
1294 return
1295 predict_rs_update_time_ms(pending_cards) +
1296 predict_rs_scan_time_ms(scanned_cards) +
1297 predict_constant_other_time_ms();
1298 }
1299
1300 double
1301 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1302 size_t rs_length = predict_rs_length_diff();
1303 size_t card_num;
1304 if (gcs_are_young()) {
1305 card_num = predict_young_card_num(rs_length);
1306 } else {
1307 card_num = predict_non_young_card_num(rs_length);
1308 }
1309 return predict_base_elapsed_time_ms(pending_cards, card_num);
1310 }
1311
1312 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1313 size_t bytes_to_copy;
1314 if (hr->is_marked())
1315 bytes_to_copy = hr->max_live_bytes();
1316 else {
1317 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1318 int age = hr->age_in_surv_rate_group();
1319 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1320 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1321 }
1322 return bytes_to_copy;
1323 }
1324
1325 double
1326 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1327 bool for_young_gc) {
1328 size_t rs_length = hr->rem_set()->occupied();
1329 size_t card_num;
1330
1331 // Predicting the number of cards is based on which type of GC
1332 // we're predicting for.
1333 if (for_young_gc) {
1334 card_num = predict_young_card_num(rs_length);
1335 } else {
1336 card_num = predict_non_young_card_num(rs_length);
1337 }
1338 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1339
1340 double region_elapsed_time_ms =
1341 predict_rs_scan_time_ms(card_num) +
1342 predict_object_copy_time_ms(bytes_to_copy);
1343
1344 // The prediction of the "other" time for this region is based
1345 // upon the region type and NOT the GC type.
1346 if (hr->is_young()) {
1347 region_elapsed_time_ms += predict_young_other_time_ms(1);
1348 } else {
1349 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1350 }
1351 return region_elapsed_time_ms;
1352 }
1353
1354 void
1355 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1356 uint survivor_cset_region_length) {
1357 _eden_cset_region_length = eden_cset_region_length;
1358 _survivor_cset_region_length = survivor_cset_region_length;
1359 _old_cset_region_length = 0;
1360 }
1361
1362 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1363 _recorded_rs_lengths = rs_lengths;
1364 }
1365
1366 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1367 double elapsed_ms) {
1368 _recent_gc_times_ms->add(elapsed_ms);
1369 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1370 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1371 }
1372
1373 size_t G1CollectorPolicy::expansion_amount() {
1374 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1375 double threshold = _gc_overhead_perc;
1376 if (recent_gc_overhead > threshold) {
1377 // We will double the existing space, or take
1378 // G1ExpandByPercentOfAvailable % of the available expansion
1379 // space, whichever is smaller, bounded below by a minimum
1380 // expansion (unless that's all that's left.)
1381 const size_t min_expand_bytes = 1*M;
1382 size_t reserved_bytes = _g1->max_capacity();
1383 size_t committed_bytes = _g1->capacity();
1384 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1385 size_t expand_bytes;
1386 size_t expand_bytes_via_pct =
1387 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1388 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1389 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1390 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1391
1392 ergo_verbose5(ErgoHeapSizing,
1393 "attempt heap expansion",
1394 ergo_format_reason("recent GC overhead higher than "
1395 "threshold after GC")
1396 ergo_format_perc("recent GC overhead")
1397 ergo_format_perc("threshold")
1398 ergo_format_byte("uncommitted")
1399 ergo_format_byte_perc("calculated expansion amount"),
1400 recent_gc_overhead, threshold,
1401 uncommitted_bytes,
1402 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1403
1404 return expand_bytes;
1405 } else {
1406 return 0;
1407 }
1408 }
1409
1410 void G1CollectorPolicy::print_tracing_info() const {
1411 _trace_young_gen_time_data.print();
1412 _trace_old_gen_time_data.print();
1413 }
1414
1415 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1416 #ifndef PRODUCT
1417 _short_lived_surv_rate_group->print_surv_rate_summary();
1418 // add this call for any other surv rate groups
1419 #endif // PRODUCT
1420 }
1421
1422 bool G1CollectorPolicy::is_young_list_full() {
1423 uint young_list_length = _g1->young_list()->length();
1424 uint young_list_target_length = _young_list_target_length;
1425 return young_list_length >= young_list_target_length;
1426 }
1427
1428 bool G1CollectorPolicy::can_expand_young_list() {
1429 uint young_list_length = _g1->young_list()->length();
1430 uint young_list_max_length = _young_list_max_length;
1431 return young_list_length < young_list_max_length;
1432 }
1433
1434 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1435 uint expansion_region_num = 0;
1436 if (GCLockerEdenExpansionPercent > 0) {
1437 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1438 double expansion_region_num_d = perc * (double) _young_list_target_length;
1439 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1440 // less than 1.0) we'll get 1.
1441 expansion_region_num = (uint) ceil(expansion_region_num_d);
1442 } else {
1443 assert(expansion_region_num == 0, "sanity");
1444 }
1445 _young_list_max_length = _young_list_target_length + expansion_region_num;
1446 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1447 }
1448
1449 // Calculates survivor space parameters.
1450 void G1CollectorPolicy::update_survivors_policy() {
1451 double max_survivor_regions_d =
1452 (double) _young_list_target_length / (double) SurvivorRatio;
1453 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1454 // smaller than 1.0) we'll get 1.
1455 _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1456
1457 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1458 HeapRegion::GrainWords * _max_survivor_regions, counters());
1459 }
1460
1461 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
1462 GCCause::Cause gc_cause) {
1463 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1464 if (!during_cycle) {
1465 ergo_verbose1(ErgoConcCycles,
1466 "request concurrent cycle initiation",
1467 ergo_format_reason("requested by GC cause")
1468 ergo_format_str("GC cause"),
1469 GCCause::to_string(gc_cause));
1470 set_initiate_conc_mark_if_possible();
1471 return true;
1472 } else {
1473 ergo_verbose1(ErgoConcCycles,
1474 "do not request concurrent cycle initiation",
1475 ergo_format_reason("concurrent cycle already in progress")
1476 ergo_format_str("GC cause"),
1477 GCCause::to_string(gc_cause));
1478 return false;
1479 }
1480 }
1481
1482 void
1483 G1CollectorPolicy::decide_on_conc_mark_initiation() {
1484 // We are about to decide on whether this pause will be an
1485 // initial-mark pause.
1486
1487 // First, during_initial_mark_pause() should not be already set. We
1488 // will set it here if we have to. However, it should be cleared by
1489 // the end of the pause (it's only set for the duration of an
1490 // initial-mark pause).
1491 assert(!during_initial_mark_pause(), "pre-condition");
1492
1493 if (initiate_conc_mark_if_possible()) {
1494 // We had noticed on a previous pause that the heap occupancy has
1495 // gone over the initiating threshold and we should start a
1496 // concurrent marking cycle. So we might initiate one.
1497
1498 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1499 if (!during_cycle) {
1500 // The concurrent marking thread is not "during a cycle", i.e.,
1501 // it has completed the last one. So we can go ahead and
1502 // initiate a new cycle.
1503
1504 set_during_initial_mark_pause();
1505 // We do not allow mixed GCs during marking.
1506 if (!gcs_are_young()) {
1507 set_gcs_are_young(true);
1508 ergo_verbose0(ErgoMixedGCs,
1509 "end mixed GCs",
1510 ergo_format_reason("concurrent cycle is about to start"));
1511 }
1512
1513 // And we can now clear initiate_conc_mark_if_possible() as
1514 // we've already acted on it.
1515 clear_initiate_conc_mark_if_possible();
1516
1517 ergo_verbose0(ErgoConcCycles,
1518 "initiate concurrent cycle",
1519 ergo_format_reason("concurrent cycle initiation requested"));
1520 } else {
1521 // The concurrent marking thread is still finishing up the
1522 // previous cycle. If we start one right now the two cycles
1523 // overlap. In particular, the concurrent marking thread might
1524 // be in the process of clearing the next marking bitmap (which
1525 // we will use for the next cycle if we start one). Starting a
1526 // cycle now will be bad given that parts of the marking
1527 // information might get cleared by the marking thread. And we
1528 // cannot wait for the marking thread to finish the cycle as it
1529 // periodically yields while clearing the next marking bitmap
1530 // and, if it's in a yield point, it's waiting for us to
1531 // finish. So, at this point we will not start a cycle and we'll
1532 // let the concurrent marking thread complete the last one.
1533 ergo_verbose0(ErgoConcCycles,
1534 "do not initiate concurrent cycle",
1535 ergo_format_reason("concurrent cycle already in progress"));
1536 }
1537 }
1538 }
1539
1540 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1541 G1CollectedHeap* _g1h;
1542 CSetChooserParUpdater _cset_updater;
1543
1544 public:
1545 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1546 uint chunk_size) :
1547 _g1h(G1CollectedHeap::heap()),
1548 _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1549
1550 bool doHeapRegion(HeapRegion* r) {
1551 // Do we have any marking information for this region?
1552 if (r->is_marked()) {
1553 // We will skip any region that's currently used as an old GC
1554 // alloc region (we should not consider those for collection
1555 // before we fill them up).
1556 if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1557 _cset_updater.add_region(r);
1558 }
1559 }
1560 return false;
1561 }
1562 };
1563
1564 class ParKnownGarbageTask: public AbstractGangTask {
1565 CollectionSetChooser* _hrSorted;
1566 uint _chunk_size;
1567 G1CollectedHeap* _g1;
1568 HeapRegionClaimer _hrclaimer;
1569
1570 public:
1571 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
1572 AbstractGangTask("ParKnownGarbageTask"),
1573 _hrSorted(hrSorted), _chunk_size(chunk_size),
1574 _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
1575
1576 void work(uint worker_id) {
1577 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1578 _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
1579 }
1580 };
1581
1582 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) {
1583 assert(n_workers > 0, "Active gc workers should be greater than 0");
1584 const uint overpartition_factor = 4;
1585 const uint min_chunk_size = MAX2(n_regions / n_workers, 1U);
1586 return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size);
1587 }
1588
1589 void
1590 G1CollectorPolicy::record_concurrent_mark_cleanup_end(uint n_workers) {
1591 _collectionSetChooser->clear();
1592
1593 uint n_regions = _g1->num_regions();
1594 uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions);
1595 _collectionSetChooser->prepare_for_par_region_addition(n_regions, chunk_size);
1596 ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers);
1597 _g1->workers()->run_task(&par_known_garbage_task);
1598
1599 _collectionSetChooser->sort_regions();
1600
1601 double end_sec = os::elapsedTime();
1602 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1603 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1604 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1605 _prev_collection_pause_end_ms += elapsed_time_ms;
1606 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true);
1607 }
1608
1609 // Add the heap region at the head of the non-incremental collection set
1610 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1611 assert(_inc_cset_build_state == Active, "Precondition");
1612 assert(hr->is_old(), "the region should be old");
1613
1614 assert(!hr->in_collection_set(), "should not already be in the CSet");
1615 _g1->register_old_region_with_cset(hr);
1616 hr->set_next_in_collection_set(_collection_set);
1617 _collection_set = hr;
1618 _collection_set_bytes_used_before += hr->used();
1619 size_t rs_length = hr->rem_set()->occupied();
1620 _recorded_rs_lengths += rs_length;
1621 _old_cset_region_length += 1;
1622 }
1623
1624 // Initialize the per-collection-set information
1625 void G1CollectorPolicy::start_incremental_cset_building() {
1626 assert(_inc_cset_build_state == Inactive, "Precondition");
1627
1628 _inc_cset_head = NULL;
1629 _inc_cset_tail = NULL;
1630 _inc_cset_bytes_used_before = 0;
1631
1632 _inc_cset_max_finger = 0;
1633 _inc_cset_recorded_rs_lengths = 0;
1634 _inc_cset_recorded_rs_lengths_diffs = 0;
1635 _inc_cset_predicted_elapsed_time_ms = 0.0;
1636 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1637 _inc_cset_build_state = Active;
1638 }
1639
1640 void G1CollectorPolicy::finalize_incremental_cset_building() {
1641 assert(_inc_cset_build_state == Active, "Precondition");
1642 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1643
1644 // The two "main" fields, _inc_cset_recorded_rs_lengths and
1645 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1646 // that adds a new region to the CSet. Further updates by the
1647 // concurrent refinement thread that samples the young RSet lengths
1648 // are accumulated in the *_diffs fields. Here we add the diffs to
1649 // the "main" fields.
1650
1651 if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1652 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1653 } else {
1654 // This is defensive. The diff should in theory be always positive
1655 // as RSets can only grow between GCs. However, given that we
1656 // sample their size concurrently with other threads updating them
1657 // it's possible that we might get the wrong size back, which
1658 // could make the calculations somewhat inaccurate.
1659 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1660 if (_inc_cset_recorded_rs_lengths >= diffs) {
1661 _inc_cset_recorded_rs_lengths -= diffs;
1662 } else {
1663 _inc_cset_recorded_rs_lengths = 0;
1664 }
1665 }
1666 _inc_cset_predicted_elapsed_time_ms +=
1667 _inc_cset_predicted_elapsed_time_ms_diffs;
1668
1669 _inc_cset_recorded_rs_lengths_diffs = 0;
1670 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1671 }
1672
1673 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1674 // This routine is used when:
1675 // * adding survivor regions to the incremental cset at the end of an
1676 // evacuation pause,
1677 // * adding the current allocation region to the incremental cset
1678 // when it is retired, and
1679 // * updating existing policy information for a region in the
1680 // incremental cset via young list RSet sampling.
1681 // Therefore this routine may be called at a safepoint by the
1682 // VM thread, or in-between safepoints by mutator threads (when
1683 // retiring the current allocation region) or a concurrent
1684 // refine thread (RSet sampling).
1685
1686 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1687 size_t used_bytes = hr->used();
1688 _inc_cset_recorded_rs_lengths += rs_length;
1689 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1690 _inc_cset_bytes_used_before += used_bytes;
1691
1692 // Cache the values we have added to the aggregated information
1693 // in the heap region in case we have to remove this region from
1694 // the incremental collection set, or it is updated by the
1695 // rset sampling code
1696 hr->set_recorded_rs_length(rs_length);
1697 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1698 }
1699
1700 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1701 size_t new_rs_length) {
1702 // Update the CSet information that is dependent on the new RS length
1703 assert(hr->is_young(), "Precondition");
1704 assert(!SafepointSynchronize::is_at_safepoint(),
1705 "should not be at a safepoint");
1706
1707 // We could have updated _inc_cset_recorded_rs_lengths and
1708 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1709 // that atomically, as this code is executed by a concurrent
1710 // refinement thread, potentially concurrently with a mutator thread
1711 // allocating a new region and also updating the same fields. To
1712 // avoid the atomic operations we accumulate these updates on two
1713 // separate fields (*_diffs) and we'll just add them to the "main"
1714 // fields at the start of a GC.
1715
1716 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1717 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1718 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1719
1720 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1721 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1722 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1723 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1724
1725 hr->set_recorded_rs_length(new_rs_length);
1726 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1727 }
1728
1729 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1730 assert(hr->is_young(), "invariant");
1731 assert(hr->young_index_in_cset() > -1, "should have already been set");
1732 assert(_inc_cset_build_state == Active, "Precondition");
1733
1734 // We need to clear and set the cached recorded/cached collection set
1735 // information in the heap region here (before the region gets added
1736 // to the collection set). An individual heap region's cached values
1737 // are calculated, aggregated with the policy collection set info,
1738 // and cached in the heap region here (initially) and (subsequently)
1739 // by the Young List sampling code.
1740
1741 size_t rs_length = hr->rem_set()->occupied();
1742 add_to_incremental_cset_info(hr, rs_length);
1743
1744 HeapWord* hr_end = hr->end();
1745 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1746
1747 assert(!hr->in_collection_set(), "invariant");
1748 _g1->register_young_region_with_cset(hr);
1749 assert(hr->next_in_collection_set() == NULL, "invariant");
1750 }
1751
1752 // Add the region at the RHS of the incremental cset
1753 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1754 // We should only ever be appending survivors at the end of a pause
1755 assert(hr->is_survivor(), "Logic");
1756
1757 // Do the 'common' stuff
1758 add_region_to_incremental_cset_common(hr);
1759
1760 // Now add the region at the right hand side
1761 if (_inc_cset_tail == NULL) {
1762 assert(_inc_cset_head == NULL, "invariant");
1763 _inc_cset_head = hr;
1764 } else {
1765 _inc_cset_tail->set_next_in_collection_set(hr);
1766 }
1767 _inc_cset_tail = hr;
1768 }
1769
1770 // Add the region to the LHS of the incremental cset
1771 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1772 // Survivors should be added to the RHS at the end of a pause
1773 assert(hr->is_eden(), "Logic");
1774
1775 // Do the 'common' stuff
1776 add_region_to_incremental_cset_common(hr);
1777
1778 // Add the region at the left hand side
1779 hr->set_next_in_collection_set(_inc_cset_head);
1780 if (_inc_cset_head == NULL) {
1781 assert(_inc_cset_tail == NULL, "Invariant");
1782 _inc_cset_tail = hr;
1783 }
1784 _inc_cset_head = hr;
1785 }
1786
1787 #ifndef PRODUCT
1788 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1789 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1790
1791 st->print_cr("\nCollection_set:");
1792 HeapRegion* csr = list_head;
1793 while (csr != NULL) {
1794 HeapRegion* next = csr->next_in_collection_set();
1795 assert(csr->in_collection_set(), "bad CS");
1796 st->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
1797 HR_FORMAT_PARAMS(csr),
1798 p2i(csr->prev_top_at_mark_start()), p2i(csr->next_top_at_mark_start()),
1799 csr->age_in_surv_rate_group_cond());
1800 csr = next;
1801 }
1802 }
1803 #endif // !PRODUCT
1804
1805 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) {
1806 // Returns the given amount of reclaimable bytes (that represents
1807 // the amount of reclaimable space still to be collected) as a
1808 // percentage of the current heap capacity.
1809 size_t capacity_bytes = _g1->capacity();
1810 return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1811 }
1812
1813 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1814 const char* false_action_str) {
1815 CollectionSetChooser* cset_chooser = _collectionSetChooser;
1816 if (cset_chooser->is_empty()) {
1817 ergo_verbose0(ErgoMixedGCs,
1818 false_action_str,
1819 ergo_format_reason("candidate old regions not available"));
1820 return false;
1821 }
1822
1823 // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1824 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1825 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1826 double threshold = (double) G1HeapWastePercent;
1827 if (reclaimable_perc <= threshold) {
1828 ergo_verbose4(ErgoMixedGCs,
1829 false_action_str,
1830 ergo_format_reason("reclaimable percentage not over threshold")
1831 ergo_format_region("candidate old regions")
1832 ergo_format_byte_perc("reclaimable")
1833 ergo_format_perc("threshold"),
1834 cset_chooser->remaining_regions(),
1835 reclaimable_bytes,
1836 reclaimable_perc, threshold);
1837 return false;
1838 }
1839
1840 ergo_verbose4(ErgoMixedGCs,
1841 true_action_str,
1842 ergo_format_reason("candidate old regions available")
1843 ergo_format_region("candidate old regions")
1844 ergo_format_byte_perc("reclaimable")
1845 ergo_format_perc("threshold"),
1846 cset_chooser->remaining_regions(),
1847 reclaimable_bytes,
1848 reclaimable_perc, threshold);
1849 return true;
1850 }
1851
1852 uint G1CollectorPolicy::calc_min_old_cset_length() {
1853 // The min old CSet region bound is based on the maximum desired
1854 // number of mixed GCs after a cycle. I.e., even if some old regions
1855 // look expensive, we should add them to the CSet anyway to make
1856 // sure we go through the available old regions in no more than the
1857 // maximum desired number of mixed GCs.
1858 //
1859 // The calculation is based on the number of marked regions we added
1860 // to the CSet chooser in the first place, not how many remain, so
1861 // that the result is the same during all mixed GCs that follow a cycle.
1862
1863 const size_t region_num = (size_t) _collectionSetChooser->length();
1864 const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
1865 size_t result = region_num / gc_num;
1866 // emulate ceiling
1867 if (result * gc_num < region_num) {
1868 result += 1;
1869 }
1870 return (uint) result;
1871 }
1872
1873 uint G1CollectorPolicy::calc_max_old_cset_length() {
1874 // The max old CSet region bound is based on the threshold expressed
1875 // as a percentage of the heap size. I.e., it should bound the
1876 // number of old regions added to the CSet irrespective of how many
1877 // of them are available.
1878
1879 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1880 const size_t region_num = g1h->num_regions();
1881 const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
1882 size_t result = region_num * perc / 100;
1883 // emulate ceiling
1884 if (100 * result < region_num * perc) {
1885 result += 1;
1886 }
1887 return (uint) result;
1888 }
1889
1890
1891 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info) {
1892 double young_start_time_sec = os::elapsedTime();
1893
1894 YoungList* young_list = _g1->young_list();
1895 finalize_incremental_cset_building();
1896
1897 guarantee(target_pause_time_ms > 0.0,
1898 err_msg("target_pause_time_ms = %1.6lf should be positive",
1899 target_pause_time_ms));
1900 guarantee(_collection_set == NULL, "Precondition");
1901
1902 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
1903 double predicted_pause_time_ms = base_time_ms;
1904 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
1905
1906 ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
1907 "start choosing CSet",
1908 ergo_format_size("_pending_cards")
1909 ergo_format_ms("predicted base time")
1910 ergo_format_ms("remaining time")
1911 ergo_format_ms("target pause time"),
1912 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
1913
1914 _last_gc_was_young = gcs_are_young() ? true : false;
1915
1916 if (_last_gc_was_young) {
1917 _trace_young_gen_time_data.increment_young_collection_count();
1918 } else {
1919 _trace_young_gen_time_data.increment_mixed_collection_count();
1920 }
1921
1922 // The young list is laid with the survivor regions from the previous
1923 // pause are appended to the RHS of the young list, i.e.
1924 // [Newly Young Regions ++ Survivors from last pause].
1925
1926 uint survivor_region_length = young_list->survivor_length();
1927 uint eden_region_length = young_list->eden_length();
1928 init_cset_region_lengths(eden_region_length, survivor_region_length);
1929
1930 HeapRegion* hr = young_list->first_survivor_region();
1931 while (hr != NULL) {
1932 assert(hr->is_survivor(), "badly formed young list");
1933 // There is a convention that all the young regions in the CSet
1934 // are tagged as "eden", so we do this for the survivors here. We
1935 // use the special set_eden_pre_gc() as it doesn't check that the
1936 // region is free (which is not the case here).
1937 hr->set_eden_pre_gc();
1938 hr = hr->get_next_young_region();
1939 }
1940
1941 // Clear the fields that point to the survivor list - they are all young now.
1942 young_list->clear_survivors();
1943
1944 _collection_set = _inc_cset_head;
1945 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
1946 time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
1947 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
1948
1949 ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
1950 "add young regions to CSet",
1951 ergo_format_region("eden")
1952 ergo_format_region("survivors")
1953 ergo_format_ms("predicted young region time"),
1954 eden_region_length, survivor_region_length,
1955 _inc_cset_predicted_elapsed_time_ms);
1956
1957 // The number of recorded young regions is the incremental
1958 // collection set's current size
1959 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
1960
1961 double young_end_time_sec = os::elapsedTime();
1962 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
1963
1964 // Set the start of the non-young choice time.
1965 double non_young_start_time_sec = young_end_time_sec;
1966
1967 if (!gcs_are_young()) {
1968 CollectionSetChooser* cset_chooser = _collectionSetChooser;
1969 cset_chooser->verify();
1970 const uint min_old_cset_length = calc_min_old_cset_length();
1971 const uint max_old_cset_length = calc_max_old_cset_length();
1972
1973 uint expensive_region_num = 0;
1974 bool check_time_remaining = adaptive_young_list_length();
1975
1976 HeapRegion* hr = cset_chooser->peek();
1977 while (hr != NULL) {
1978 if (old_cset_region_length() >= max_old_cset_length) {
1979 // Added maximum number of old regions to the CSet.
1980 ergo_verbose2(ErgoCSetConstruction,
1981 "finish adding old regions to CSet",
1982 ergo_format_reason("old CSet region num reached max")
1983 ergo_format_region("old")
1984 ergo_format_region("max"),
1985 old_cset_region_length(), max_old_cset_length);
1986 break;
1987 }
1988
1989
1990 // Stop adding regions if the remaining reclaimable space is
1991 // not above G1HeapWastePercent.
1992 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1993 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1994 double threshold = (double) G1HeapWastePercent;
1995 if (reclaimable_perc <= threshold) {
1996 // We've added enough old regions that the amount of uncollected
1997 // reclaimable space is at or below the waste threshold. Stop
1998 // adding old regions to the CSet.
1999 ergo_verbose5(ErgoCSetConstruction,
2000 "finish adding old regions to CSet",
2001 ergo_format_reason("reclaimable percentage not over threshold")
2002 ergo_format_region("old")
2003 ergo_format_region("max")
2004 ergo_format_byte_perc("reclaimable")
2005 ergo_format_perc("threshold"),
2006 old_cset_region_length(),
2007 max_old_cset_length,
2008 reclaimable_bytes,
2009 reclaimable_perc, threshold);
2010 break;
2011 }
2012
2013 double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
2014 if (check_time_remaining) {
2015 if (predicted_time_ms > time_remaining_ms) {
2016 // Too expensive for the current CSet.
2017
2018 if (old_cset_region_length() >= min_old_cset_length) {
2019 // We have added the minimum number of old regions to the CSet,
2020 // we are done with this CSet.
2021 ergo_verbose4(ErgoCSetConstruction,
2022 "finish adding old regions to CSet",
2023 ergo_format_reason("predicted time is too high")
2024 ergo_format_ms("predicted time")
2025 ergo_format_ms("remaining time")
2026 ergo_format_region("old")
2027 ergo_format_region("min"),
2028 predicted_time_ms, time_remaining_ms,
2029 old_cset_region_length(), min_old_cset_length);
2030 break;
2031 }
2032
2033 // We'll add it anyway given that we haven't reached the
2034 // minimum number of old regions.
2035 expensive_region_num += 1;
2036 }
2037 } else {
2038 if (old_cset_region_length() >= min_old_cset_length) {
2039 // In the non-auto-tuning case, we'll finish adding regions
2040 // to the CSet if we reach the minimum.
2041 ergo_verbose2(ErgoCSetConstruction,
2042 "finish adding old regions to CSet",
2043 ergo_format_reason("old CSet region num reached min")
2044 ergo_format_region("old")
2045 ergo_format_region("min"),
2046 old_cset_region_length(), min_old_cset_length);
2047 break;
2048 }
2049 }
2050
2051 // We will add this region to the CSet.
2052 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2053 predicted_pause_time_ms += predicted_time_ms;
2054 cset_chooser->remove_and_move_to_next(hr);
2055 _g1->old_set_remove(hr);
2056 add_old_region_to_cset(hr);
2057
2058 hr = cset_chooser->peek();
2059 }
2060 if (hr == NULL) {
2061 ergo_verbose0(ErgoCSetConstruction,
2062 "finish adding old regions to CSet",
2063 ergo_format_reason("candidate old regions not available"));
2064 }
2065
2066 if (expensive_region_num > 0) {
2067 // We print the information once here at the end, predicated on
2068 // whether we added any apparently expensive regions or not, to
2069 // avoid generating output per region.
2070 ergo_verbose4(ErgoCSetConstruction,
2071 "added expensive regions to CSet",
2072 ergo_format_reason("old CSet region num not reached min")
2073 ergo_format_region("old")
2074 ergo_format_region("expensive")
2075 ergo_format_region("min")
2076 ergo_format_ms("remaining time"),
2077 old_cset_region_length(),
2078 expensive_region_num,
2079 min_old_cset_length,
2080 time_remaining_ms);
2081 }
2082
2083 cset_chooser->verify();
2084 }
2085
2086 stop_incremental_cset_building();
2087
2088 ergo_verbose5(ErgoCSetConstruction,
2089 "finish choosing CSet",
2090 ergo_format_region("eden")
2091 ergo_format_region("survivors")
2092 ergo_format_region("old")
2093 ergo_format_ms("predicted pause time")
2094 ergo_format_ms("target pause time"),
2095 eden_region_length, survivor_region_length,
2096 old_cset_region_length(),
2097 predicted_pause_time_ms, target_pause_time_ms);
2098
2099 double non_young_end_time_sec = os::elapsedTime();
2100 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2101 evacuation_info.set_collectionset_regions(cset_region_length());
2102 }
2103
2104 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) {
2105 if(TraceYoungGenTime) {
2106 _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2107 }
2108 }
2109
2110 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) {
2111 if(TraceYoungGenTime) {
2112 _all_yield_times_ms.add(yield_time_ms);
2113 }
2114 }
2115
2116 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2117 if(TraceYoungGenTime) {
2118 _total.add(pause_time_ms);
2119 _other.add(pause_time_ms - phase_times->accounted_time_ms());
2120 _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2121 _parallel.add(phase_times->cur_collection_par_time_ms());
2122 _ext_root_scan.add(phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan));
2123 _satb_filtering.add(phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering));
2124 _update_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS));
2125 _scan_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::ScanRS));
2126 _obj_copy.add(phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy));
2127 _termination.add(phase_times->average_time_ms(G1GCPhaseTimes::Termination));
2128
2129 double parallel_known_time = phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan) +
2130 phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering) +
2131 phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS) +
2132 phase_times->average_time_ms(G1GCPhaseTimes::ScanRS) +
2133 phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy) +
2134 phase_times->average_time_ms(G1GCPhaseTimes::Termination);
2135
2136 double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2137 _parallel_other.add(parallel_other_time);
2138 _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2139 }
2140 }
2141
2142 void TraceYoungGenTimeData::increment_young_collection_count() {
2143 if(TraceYoungGenTime) {
2144 ++_young_pause_num;
2145 }
2146 }
2147
2148 void TraceYoungGenTimeData::increment_mixed_collection_count() {
2149 if(TraceYoungGenTime) {
2150 ++_mixed_pause_num;
2151 }
2152 }
2153
2154 void TraceYoungGenTimeData::print_summary(const char* str,
2155 const NumberSeq* seq) const {
2156 double sum = seq->sum();
2157 gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2158 str, sum / 1000.0, seq->avg());
2159 }
2160
2161 void TraceYoungGenTimeData::print_summary_sd(const char* str,
2162 const NumberSeq* seq) const {
2163 print_summary(str, seq);
2164 gclog_or_tty->print_cr("%45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2165 "(num", seq->num(), seq->sd(), seq->maximum());
2166 }
2167
2168 void TraceYoungGenTimeData::print() const {
2169 if (!TraceYoungGenTime) {
2170 return;
2171 }
2172
2173 gclog_or_tty->print_cr("ALL PAUSES");
2174 print_summary_sd(" Total", &_total);
2175 gclog_or_tty->cr();
2176 gclog_or_tty->cr();
2177 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num);
2178 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num);
2179 gclog_or_tty->cr();
2180
2181 gclog_or_tty->print_cr("EVACUATION PAUSES");
2182
2183 if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2184 gclog_or_tty->print_cr("none");
2185 } else {
2186 print_summary_sd(" Evacuation Pauses", &_total);
2187 print_summary(" Root Region Scan Wait", &_root_region_scan_wait);
2188 print_summary(" Parallel Time", &_parallel);
2189 print_summary(" Ext Root Scanning", &_ext_root_scan);
2190 print_summary(" SATB Filtering", &_satb_filtering);
2191 print_summary(" Update RS", &_update_rs);
2192 print_summary(" Scan RS", &_scan_rs);
2193 print_summary(" Object Copy", &_obj_copy);
2194 print_summary(" Termination", &_termination);
2195 print_summary(" Parallel Other", &_parallel_other);
2196 print_summary(" Clear CT", &_clear_ct);
2197 print_summary(" Other", &_other);
2198 }
2199 gclog_or_tty->cr();
2200
2201 gclog_or_tty->print_cr("MISC");
2202 print_summary_sd(" Stop World", &_all_stop_world_times_ms);
2203 print_summary_sd(" Yields", &_all_yield_times_ms);
2204 }
2205
2206 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) {
2207 if (TraceOldGenTime) {
2208 _all_full_gc_times.add(full_gc_time_ms);
2209 }
2210 }
2211
2212 void TraceOldGenTimeData::print() const {
2213 if (!TraceOldGenTime) {
2214 return;
2215 }
2216
2217 if (_all_full_gc_times.num() > 0) {
2218 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2219 _all_full_gc_times.num(),
2220 _all_full_gc_times.sum() / 1000.0);
2221 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2222 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2223 _all_full_gc_times.sd(),
2224 _all_full_gc_times.maximum());
2225 }
2226 }