1 /*
2 * Copyright (c) 2001, 2013, 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(G1CollectedHeap::use_parallel_gc_threads()
83 ? ParallelGCThreads : 1),
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 _gcs_are_young(true),
112
113 _during_marking(false),
114 _in_marking_window(false),
115 _in_marking_window_im(false),
116
117 _recent_prev_end_times_for_all_gcs_sec(
118 new TruncatedSeq(NumPrevPausesForHeuristics)),
119
120 _recent_avg_pause_time_ratio(0.0),
121
122 _initiate_conc_mark_if_possible(false),
123 _during_initial_mark_pause(false),
124 _last_young_gc(false),
125 _last_gc_was_young(false),
126
127 _eden_used_bytes_before_gc(0),
128 _survivor_used_bytes_before_gc(0),
129 _heap_used_bytes_before_gc(0),
130 _metaspace_used_bytes_before_gc(0),
131 _eden_capacity_bytes_before_gc(0),
132 _heap_capacity_bytes_before_gc(0),
133
134 _eden_cset_region_length(0),
135 _survivor_cset_region_length(0),
136 _old_cset_region_length(0),
137
138 _collection_set(NULL),
139 _collection_set_bytes_used_before(0),
140
141 // Incremental CSet attributes
142 _inc_cset_build_state(Inactive),
143 _inc_cset_head(NULL),
144 _inc_cset_tail(NULL),
145 _inc_cset_bytes_used_before(0),
146 _inc_cset_max_finger(NULL),
147 _inc_cset_recorded_rs_lengths(0),
148 _inc_cset_recorded_rs_lengths_diffs(0),
149 _inc_cset_predicted_elapsed_time_ms(0.0),
150 _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
151
152 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
153 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
154 #endif // _MSC_VER
155
156 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
157 G1YoungSurvRateNumRegionsSummary)),
158 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
159 G1YoungSurvRateNumRegionsSummary)),
160 // add here any more surv rate groups
161 _recorded_survivor_regions(0),
162 _recorded_survivor_head(NULL),
163 _recorded_survivor_tail(NULL),
164 _survivors_age_table(true),
165
166 _gc_overhead_perc(0.0) {
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 uintx confidence_perc = G1ConfidencePercent;
283 // Put an artificial ceiling on this so that it's not set to a silly value.
284 if (confidence_perc > 100) {
285 confidence_perc = 100;
286 warning("G1ConfidencePercent is set to a value that is too large, "
287 "it's been updated to %u", confidence_perc);
288 }
289 _sigma = (double) confidence_perc / 100.0;
290
291 // start conservatively (around 50ms is about right)
292 _concurrent_mark_remark_times_ms->add(0.05);
293 _concurrent_mark_cleanup_times_ms->add(0.20);
294 _tenuring_threshold = MaxTenuringThreshold;
295 // _max_survivor_regions will be calculated by
296 // update_young_list_target_length() during initialization.
297 _max_survivor_regions = 0;
298
299 assert(GCTimeRatio > 0,
300 "we should have set it to a default value set_g1_gc_flags() "
301 "if a user set it to 0");
302 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
303
304 uintx reserve_perc = G1ReservePercent;
305 // Put an artificial ceiling on this so that it's not set to a silly value.
306 if (reserve_perc > 50) {
307 reserve_perc = 50;
308 warning("G1ReservePercent is set to a value that is too large, "
309 "it's been updated to %u", reserve_perc);
310 }
311 _reserve_factor = (double) reserve_perc / 100.0;
312 // This will be set when the heap is expanded
313 // for the first time during initialization.
314 _reserve_regions = 0;
315
316 _collectionSetChooser = new CollectionSetChooser();
317 }
318
319 void G1CollectorPolicy::initialize_alignments() {
320 _space_alignment = HeapRegion::GrainBytes;
321 size_t card_table_alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
322 size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
323 _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
324 }
325
326 void G1CollectorPolicy::initialize_flags() {
327 if (G1HeapRegionSize != HeapRegion::GrainBytes) {
328 FLAG_SET_ERGO(uintx, G1HeapRegionSize, HeapRegion::GrainBytes);
329 }
330
331 if (SurvivorRatio < 1) {
332 vm_exit_during_initialization("Invalid survivor ratio specified");
333 }
334 CollectorPolicy::initialize_flags();
335 _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
336 }
337
338 void G1CollectorPolicy::post_heap_initialize() {
339 uintx max_regions = G1CollectedHeap::heap()->max_regions();
340 size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
341 if (max_young_size != MaxNewSize) {
342 FLAG_SET_ERGO(uintx, MaxNewSize, max_young_size);
343 }
344 }
345
346 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
347 _min_desired_young_length(0), _max_desired_young_length(0) {
348 if (FLAG_IS_CMDLINE(NewRatio)) {
349 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
350 warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
351 } else {
352 _sizer_kind = SizerNewRatio;
353 _adaptive_size = false;
354 return;
355 }
356 }
357
358 if (FLAG_IS_CMDLINE(NewSize) && FLAG_IS_CMDLINE(MaxNewSize) && NewSize > MaxNewSize) {
359 vm_exit_during_initialization("Initial young gen size set larger than the maximum young gen size");
360 }
361
362 if (FLAG_IS_CMDLINE(NewSize)) {
363 _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
364 1U);
365 if (FLAG_IS_CMDLINE(MaxNewSize)) {
366 _max_desired_young_length =
367 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
368 1U);
369 _sizer_kind = SizerMaxAndNewSize;
370 _adaptive_size = _min_desired_young_length == _max_desired_young_length;
371 } else {
372 _sizer_kind = SizerNewSizeOnly;
373 }
374 } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
375 _max_desired_young_length =
376 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
377 1U);
378 _sizer_kind = SizerMaxNewSizeOnly;
379 }
380 }
381
382 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
383 uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
384 return MAX2(1U, default_value);
385 }
386
387 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
388 uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
389 return MAX2(1U, default_value);
390 }
391
392 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
393 assert(number_of_heap_regions > 0, "Heap must be initialized");
394
395 switch (_sizer_kind) {
396 case SizerDefaults:
397 *min_young_length = calculate_default_min_length(number_of_heap_regions);
398 *max_young_length = calculate_default_max_length(number_of_heap_regions);
399 break;
400 case SizerNewSizeOnly:
401 *max_young_length = calculate_default_max_length(number_of_heap_regions);
402 *max_young_length = MAX2(*min_young_length, *max_young_length);
403 break;
404 case SizerMaxNewSizeOnly:
405 *min_young_length = calculate_default_min_length(number_of_heap_regions);
406 *min_young_length = MIN2(*min_young_length, *max_young_length);
407 break;
408 case SizerMaxAndNewSize:
409 // Do nothing. Values set on the command line, don't update them at runtime.
410 break;
411 case SizerNewRatio:
412 *min_young_length = number_of_heap_regions / (NewRatio + 1);
413 *max_young_length = *min_young_length;
414 break;
415 default:
416 ShouldNotReachHere();
417 }
418
419 assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
420 }
421
422 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
423 // We need to pass the desired values because recalculation may not update these
424 // values in some cases.
425 uint temp = _min_desired_young_length;
426 uint result = _max_desired_young_length;
427 recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
428 return result;
429 }
430
431 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
432 recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
433 &_max_desired_young_length);
434 }
435
436 void G1CollectorPolicy::init() {
437 // Set aside an initial future to_space.
438 _g1 = G1CollectedHeap::heap();
439
440 assert(Heap_lock->owned_by_self(), "Locking discipline.");
441
442 initialize_gc_policy_counters();
443
444 if (adaptive_young_list_length()) {
445 _young_list_fixed_length = 0;
446 } else {
447 _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
448 }
449 _free_regions_at_end_of_collection = _g1->free_regions();
450 update_young_list_target_length();
451
452 // We may immediately start allocating regions and placing them on the
453 // collection set list. Initialize the per-collection set info
454 start_incremental_cset_building();
455 }
456
457 // Create the jstat counters for the policy.
458 void G1CollectorPolicy::initialize_gc_policy_counters() {
459 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
460 }
461
462 bool G1CollectorPolicy::predict_will_fit(uint young_length,
463 double base_time_ms,
464 uint base_free_regions,
465 double target_pause_time_ms) {
466 if (young_length >= base_free_regions) {
467 // end condition 1: not enough space for the young regions
468 return false;
469 }
470
471 double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
472 size_t bytes_to_copy =
473 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
474 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
475 double young_other_time_ms = predict_young_other_time_ms(young_length);
476 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
477 if (pause_time_ms > target_pause_time_ms) {
478 // end condition 2: prediction is over the target pause time
479 return false;
480 }
481
482 size_t free_bytes =
483 (base_free_regions - young_length) * HeapRegion::GrainBytes;
484 if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
485 // end condition 3: out-of-space (conservatively!)
486 return false;
487 }
488
489 // success!
490 return true;
491 }
492
493 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
494 // re-calculate the necessary reserve
495 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
496 // We use ceiling so that if reserve_regions_d is > 0.0 (but
497 // smaller than 1.0) we'll get 1.
498 _reserve_regions = (uint) ceil(reserve_regions_d);
499
500 _young_gen_sizer->heap_size_changed(new_number_of_regions);
501 }
502
503 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
504 uint base_min_length) {
505 uint desired_min_length = 0;
506 if (adaptive_young_list_length()) {
507 if (_alloc_rate_ms_seq->num() > 3) {
508 double now_sec = os::elapsedTime();
509 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
510 double alloc_rate_ms = predict_alloc_rate_ms();
511 desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
512 } else {
513 // otherwise we don't have enough info to make the prediction
514 }
515 }
516 desired_min_length += base_min_length;
517 // make sure we don't go below any user-defined minimum bound
518 return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
519 }
520
521 uint G1CollectorPolicy::calculate_young_list_desired_max_length() {
522 // Here, we might want to also take into account any additional
523 // constraints (i.e., user-defined minimum bound). Currently, we
524 // effectively don't set this bound.
525 return _young_gen_sizer->max_desired_young_length();
526 }
527
528 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
529 if (rs_lengths == (size_t) -1) {
530 // if it's set to the default value (-1), we should predict it;
531 // otherwise, use the given value.
532 rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
533 }
534
535 // Calculate the absolute and desired min bounds.
536
537 // This is how many young regions we already have (currently: the survivors).
538 uint base_min_length = recorded_survivor_regions();
539 // This is the absolute minimum young length, which ensures that we
540 // can allocate one eden region in the worst-case.
541 uint absolute_min_length = base_min_length + 1;
542 uint desired_min_length =
543 calculate_young_list_desired_min_length(base_min_length);
544 if (desired_min_length < absolute_min_length) {
545 desired_min_length = absolute_min_length;
546 }
547
548 // Calculate the absolute and desired max bounds.
549
550 // We will try our best not to "eat" into the reserve.
551 uint absolute_max_length = 0;
552 if (_free_regions_at_end_of_collection > _reserve_regions) {
553 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
554 }
555 uint desired_max_length = calculate_young_list_desired_max_length();
556 if (desired_max_length > absolute_max_length) {
557 desired_max_length = absolute_max_length;
558 }
559
560 uint young_list_target_length = 0;
561 if (adaptive_young_list_length()) {
562 if (gcs_are_young()) {
563 young_list_target_length =
564 calculate_young_list_target_length(rs_lengths,
565 base_min_length,
566 desired_min_length,
567 desired_max_length);
568 _rs_lengths_prediction = rs_lengths;
569 } else {
570 // Don't calculate anything and let the code below bound it to
571 // the desired_min_length, i.e., do the next GC as soon as
572 // possible to maximize how many old regions we can add to it.
573 }
574 } else {
575 // The user asked for a fixed young gen so we'll fix the young gen
576 // whether the next GC is young or mixed.
577 young_list_target_length = _young_list_fixed_length;
578 }
579
580 // Make sure we don't go over the desired max length, nor under the
581 // desired min length. In case they clash, desired_min_length wins
582 // which is why that test is second.
583 if (young_list_target_length > desired_max_length) {
584 young_list_target_length = desired_max_length;
585 }
586 if (young_list_target_length < desired_min_length) {
587 young_list_target_length = desired_min_length;
588 }
589
590 assert(young_list_target_length > recorded_survivor_regions(),
591 "we should be able to allocate at least one eden region");
592 assert(young_list_target_length >= absolute_min_length, "post-condition");
593 _young_list_target_length = young_list_target_length;
594
595 update_max_gc_locker_expansion();
596 }
597
598 uint
599 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
600 uint base_min_length,
601 uint desired_min_length,
602 uint desired_max_length) {
603 assert(adaptive_young_list_length(), "pre-condition");
604 assert(gcs_are_young(), "only call this for young GCs");
605
606 // In case some edge-condition makes the desired max length too small...
607 if (desired_max_length <= desired_min_length) {
608 return desired_min_length;
609 }
610
611 // We'll adjust min_young_length and max_young_length not to include
612 // the already allocated young regions (i.e., so they reflect the
613 // min and max eden regions we'll allocate). The base_min_length
614 // will be reflected in the predictions by the
615 // survivor_regions_evac_time prediction.
616 assert(desired_min_length > base_min_length, "invariant");
617 uint min_young_length = desired_min_length - base_min_length;
618 assert(desired_max_length > base_min_length, "invariant");
619 uint max_young_length = desired_max_length - base_min_length;
620
621 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
622 double survivor_regions_evac_time = predict_survivor_regions_evac_time();
623 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
624 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
625 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
626 double base_time_ms =
627 predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
628 survivor_regions_evac_time;
629 uint available_free_regions = _free_regions_at_end_of_collection;
630 uint base_free_regions = 0;
631 if (available_free_regions > _reserve_regions) {
632 base_free_regions = available_free_regions - _reserve_regions;
633 }
634
635 // Here, we will make sure that the shortest young length that
636 // makes sense fits within the target pause time.
637
638 if (predict_will_fit(min_young_length, base_time_ms,
639 base_free_regions, target_pause_time_ms)) {
640 // The shortest young length will fit into the target pause time;
641 // we'll now check whether the absolute maximum number of young
642 // regions will fit in the target pause time. If not, we'll do
643 // a binary search between min_young_length and max_young_length.
644 if (predict_will_fit(max_young_length, base_time_ms,
645 base_free_regions, target_pause_time_ms)) {
646 // The maximum young length will fit into the target pause time.
647 // We are done so set min young length to the maximum length (as
648 // the result is assumed to be returned in min_young_length).
649 min_young_length = max_young_length;
650 } else {
651 // The maximum possible number of young regions will not fit within
652 // the target pause time so we'll search for the optimal
653 // length. The loop invariants are:
654 //
655 // min_young_length < max_young_length
656 // min_young_length is known to fit into the target pause time
657 // max_young_length is known not to fit into the target pause time
658 //
659 // Going into the loop we know the above hold as we've just
660 // checked them. Every time around the loop we check whether
661 // the middle value between min_young_length and
662 // max_young_length fits into the target pause time. If it
663 // does, it becomes the new min. If it doesn't, it becomes
664 // the new max. This way we maintain the loop invariants.
665
666 assert(min_young_length < max_young_length, "invariant");
667 uint diff = (max_young_length - min_young_length) / 2;
668 while (diff > 0) {
669 uint young_length = min_young_length + diff;
670 if (predict_will_fit(young_length, base_time_ms,
671 base_free_regions, target_pause_time_ms)) {
672 min_young_length = young_length;
673 } else {
674 max_young_length = young_length;
675 }
676 assert(min_young_length < max_young_length, "invariant");
677 diff = (max_young_length - min_young_length) / 2;
678 }
679 // The results is min_young_length which, according to the
680 // loop invariants, should fit within the target pause time.
681
682 // These are the post-conditions of the binary search above:
683 assert(min_young_length < max_young_length,
684 "otherwise we should have discovered that max_young_length "
685 "fits into the pause target and not done the binary search");
686 assert(predict_will_fit(min_young_length, base_time_ms,
687 base_free_regions, target_pause_time_ms),
688 "min_young_length, the result of the binary search, should "
689 "fit into the pause target");
690 assert(!predict_will_fit(min_young_length + 1, base_time_ms,
691 base_free_regions, target_pause_time_ms),
692 "min_young_length, the result of the binary search, should be "
693 "optimal, so no larger length should fit into the pause target");
694 }
695 } else {
696 // Even the minimum length doesn't fit into the pause time
697 // target, return it as the result nevertheless.
698 }
699 return base_min_length + min_young_length;
700 }
701
702 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
703 double survivor_regions_evac_time = 0.0;
704 for (HeapRegion * r = _recorded_survivor_head;
705 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
706 r = r->get_next_young_region()) {
707 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young());
708 }
709 return survivor_regions_evac_time;
710 }
711
712 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
713 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
714
715 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
716 if (rs_lengths > _rs_lengths_prediction) {
717 // add 10% to avoid having to recalculate often
718 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
719 update_young_list_target_length(rs_lengths_prediction);
720 }
721 }
722
723
724
725 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
726 bool is_tlab,
727 bool* gc_overhead_limit_was_exceeded) {
728 guarantee(false, "Not using this policy feature yet.");
729 return NULL;
730 }
731
732 // This method controls how a collector handles one or more
733 // of its generations being fully allocated.
734 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
735 bool is_tlab) {
736 guarantee(false, "Not using this policy feature yet.");
737 return NULL;
738 }
739
740
741 #ifndef PRODUCT
742 bool G1CollectorPolicy::verify_young_ages() {
743 HeapRegion* head = _g1->young_list()->first_region();
744 return
745 verify_young_ages(head, _short_lived_surv_rate_group);
746 // also call verify_young_ages on any additional surv rate groups
747 }
748
749 bool
750 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
751 SurvRateGroup *surv_rate_group) {
752 guarantee( surv_rate_group != NULL, "pre-condition" );
753
754 const char* name = surv_rate_group->name();
755 bool ret = true;
756 int prev_age = -1;
757
758 for (HeapRegion* curr = head;
759 curr != NULL;
760 curr = curr->get_next_young_region()) {
761 SurvRateGroup* group = curr->surv_rate_group();
762 if (group == NULL && !curr->is_survivor()) {
763 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
764 ret = false;
765 }
766
767 if (surv_rate_group == group) {
768 int age = curr->age_in_surv_rate_group();
769
770 if (age < 0) {
771 gclog_or_tty->print_cr("## %s: encountered negative age", name);
772 ret = false;
773 }
774
775 if (age <= prev_age) {
776 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
777 "(%d, %d)", name, age, prev_age);
778 ret = false;
779 }
780 prev_age = age;
781 }
782 }
783
784 return ret;
785 }
786 #endif // PRODUCT
787
788 void G1CollectorPolicy::record_full_collection_start() {
789 _full_collection_start_sec = os::elapsedTime();
790 record_heap_size_info_at_start(true /* full */);
791 // Release the future to-space so that it is available for compaction into.
792 _g1->set_full_collection();
793 }
794
795 void G1CollectorPolicy::record_full_collection_end() {
796 // Consider this like a collection pause for the purposes of allocation
797 // since last pause.
798 double end_sec = os::elapsedTime();
799 double full_gc_time_sec = end_sec - _full_collection_start_sec;
800 double full_gc_time_ms = full_gc_time_sec * 1000.0;
801
802 _trace_gen1_time_data.record_full_collection(full_gc_time_ms);
803
804 update_recent_gc_times(end_sec, full_gc_time_ms);
805
806 _g1->clear_full_collection();
807
808 // "Nuke" the heuristics that control the young/mixed GC
809 // transitions and make sure we start with young GCs after the Full GC.
810 set_gcs_are_young(true);
811 _last_young_gc = false;
812 clear_initiate_conc_mark_if_possible();
813 clear_during_initial_mark_pause();
814 _in_marking_window = false;
815 _in_marking_window_im = false;
816
817 _short_lived_surv_rate_group->start_adding_regions();
818 // also call this on any additional surv rate groups
819
820 record_survivor_regions(0, NULL, NULL);
821
822 _free_regions_at_end_of_collection = _g1->free_regions();
823 // Reset survivors SurvRateGroup.
824 _survivor_surv_rate_group->reset();
825 update_young_list_target_length();
826 _collectionSetChooser->clear();
827 }
828
829 void G1CollectorPolicy::record_stop_world_start() {
830 _stop_world_start = os::elapsedTime();
831 }
832
833 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
834 // We only need to do this here as the policy will only be applied
835 // to the GC we're about to start. so, no point is calculating this
836 // every time we calculate / recalculate the target young length.
837 update_survivors_policy();
838
839 assert(_g1->used() == _g1->recalculate_used(),
840 err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
841 _g1->used(), _g1->recalculate_used()));
842
843 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
844 _trace_gen0_time_data.record_start_collection(s_w_t_ms);
845 _stop_world_start = 0.0;
846
847 record_heap_size_info_at_start(false /* full */);
848
849 phase_times()->record_cur_collection_start_sec(start_time_sec);
850 _pending_cards = _g1->pending_card_num();
851
852 _collection_set_bytes_used_before = 0;
853 _bytes_copied_during_gc = 0;
854
855 _last_gc_was_young = false;
856
857 // do that for any other surv rate groups
858 _short_lived_surv_rate_group->stop_adding_regions();
859 _survivors_age_table.clear();
860
861 assert( verify_young_ages(), "region age verification" );
862 }
863
864 void G1CollectorPolicy::record_concurrent_mark_init_end(double
865 mark_init_elapsed_time_ms) {
866 _during_marking = true;
867 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
868 clear_during_initial_mark_pause();
869 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
870 }
871
872 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
873 _mark_remark_start_sec = os::elapsedTime();
874 _during_marking = false;
875 }
876
877 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
878 double end_time_sec = os::elapsedTime();
879 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
880 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
881 _cur_mark_stop_world_time_ms += elapsed_time_ms;
882 _prev_collection_pause_end_ms += elapsed_time_ms;
883
884 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
885 }
886
887 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
888 _mark_cleanup_start_sec = os::elapsedTime();
889 }
890
891 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
892 _last_young_gc = true;
893 _in_marking_window = false;
894 }
895
896 void G1CollectorPolicy::record_concurrent_pause() {
897 if (_stop_world_start > 0.0) {
898 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
899 _trace_gen0_time_data.record_yield_time(yield_ms);
900 }
901 }
902
903 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
904 if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
905 return false;
906 }
907
908 size_t marking_initiating_used_threshold =
909 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
910 size_t cur_used_bytes = _g1->non_young_capacity_bytes();
911 size_t alloc_byte_size = alloc_word_size * HeapWordSize;
912
913 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
914 if (gcs_are_young() && !_last_young_gc) {
915 ergo_verbose5(ErgoConcCycles,
916 "request concurrent cycle initiation",
917 ergo_format_reason("occupancy higher than threshold")
918 ergo_format_byte("occupancy")
919 ergo_format_byte("allocation request")
920 ergo_format_byte_perc("threshold")
921 ergo_format_str("source"),
922 cur_used_bytes,
923 alloc_byte_size,
924 marking_initiating_used_threshold,
925 (double) InitiatingHeapOccupancyPercent,
926 source);
927 return true;
928 } else {
929 ergo_verbose5(ErgoConcCycles,
930 "do not request concurrent cycle initiation",
931 ergo_format_reason("still doing mixed collections")
932 ergo_format_byte("occupancy")
933 ergo_format_byte("allocation request")
934 ergo_format_byte_perc("threshold")
935 ergo_format_str("source"),
936 cur_used_bytes,
937 alloc_byte_size,
938 marking_initiating_used_threshold,
939 (double) InitiatingHeapOccupancyPercent,
940 source);
941 }
942 }
943
944 return false;
945 }
946
947 // Anything below that is considered to be zero
948 #define MIN_TIMER_GRANULARITY 0.0000001
949
950 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info) {
951 double end_time_sec = os::elapsedTime();
952 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
953 "otherwise, the subtraction below does not make sense");
954 size_t rs_size =
955 _cur_collection_pause_used_regions_at_start - cset_region_length();
956 size_t cur_used_bytes = _g1->used();
957 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
958 bool last_pause_included_initial_mark = false;
959 bool update_stats = !_g1->evacuation_failed();
960
961 #ifndef PRODUCT
962 if (G1YoungSurvRateVerbose) {
963 gclog_or_tty->print_cr("");
964 _short_lived_surv_rate_group->print();
965 // do that for any other surv rate groups too
966 }
967 #endif // PRODUCT
968
969 last_pause_included_initial_mark = during_initial_mark_pause();
970 if (last_pause_included_initial_mark) {
971 record_concurrent_mark_init_end(0.0);
972 } else if (need_to_start_conc_mark("end of GC")) {
973 // Note: this might have already been set, if during the last
974 // pause we decided to start a cycle but at the beginning of
975 // this pause we decided to postpone it. That's OK.
976 set_initiate_conc_mark_if_possible();
977 }
978
979 _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0,
980 end_time_sec, false);
981
982 evacuation_info.set_collectionset_used_before(_collection_set_bytes_used_before);
983 evacuation_info.set_bytes_copied(_bytes_copied_during_gc);
984
985 if (update_stats) {
986 _trace_gen0_time_data.record_end_collection(pause_time_ms, phase_times());
987 // this is where we update the allocation rate of the application
988 double app_time_ms =
989 (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
990 if (app_time_ms < MIN_TIMER_GRANULARITY) {
991 // This usually happens due to the timer not having the required
992 // granularity. Some Linuxes are the usual culprits.
993 // We'll just set it to something (arbitrarily) small.
994 app_time_ms = 1.0;
995 }
996 // We maintain the invariant that all objects allocated by mutator
997 // threads will be allocated out of eden regions. So, we can use
998 // the eden region number allocated since the previous GC to
999 // calculate the application's allocate rate. The only exception
1000 // to that is humongous objects that are allocated separately. But
1001 // given that humongous object allocations do not really affect
1002 // either the pause's duration nor when the next pause will take
1003 // place we can safely ignore them here.
1004 uint regions_allocated = eden_cset_region_length();
1005 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1006 _alloc_rate_ms_seq->add(alloc_rate_ms);
1007
1008 double interval_ms =
1009 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1010 update_recent_gc_times(end_time_sec, pause_time_ms);
1011 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1012 if (recent_avg_pause_time_ratio() < 0.0 ||
1013 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1014 #ifndef PRODUCT
1015 // Dump info to allow post-facto debugging
1016 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1017 gclog_or_tty->print_cr("-------------------------------------------");
1018 gclog_or_tty->print_cr("Recent GC Times (ms):");
1019 _recent_gc_times_ms->dump();
1020 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1021 _recent_prev_end_times_for_all_gcs_sec->dump();
1022 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1023 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1024 // In debug mode, terminate the JVM if the user wants to debug at this point.
1025 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1026 #endif // !PRODUCT
1027 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1028 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1029 if (_recent_avg_pause_time_ratio < 0.0) {
1030 _recent_avg_pause_time_ratio = 0.0;
1031 } else {
1032 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1033 _recent_avg_pause_time_ratio = 1.0;
1034 }
1035 }
1036 }
1037
1038 bool new_in_marking_window = _in_marking_window;
1039 bool new_in_marking_window_im = false;
1040 if (during_initial_mark_pause()) {
1041 new_in_marking_window = true;
1042 new_in_marking_window_im = true;
1043 }
1044
1045 if (_last_young_gc) {
1046 // This is supposed to to be the "last young GC" before we start
1047 // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1048
1049 if (!last_pause_included_initial_mark) {
1050 if (next_gc_should_be_mixed("start mixed GCs",
1051 "do not start mixed GCs")) {
1052 set_gcs_are_young(false);
1053 }
1054 } else {
1055 ergo_verbose0(ErgoMixedGCs,
1056 "do not start mixed GCs",
1057 ergo_format_reason("concurrent cycle is about to start"));
1058 }
1059 _last_young_gc = false;
1060 }
1061
1062 if (!_last_gc_was_young) {
1063 // This is a mixed GC. Here we decide whether to continue doing
1064 // mixed GCs or not.
1065
1066 if (!next_gc_should_be_mixed("continue mixed GCs",
1067 "do not continue mixed GCs")) {
1068 set_gcs_are_young(true);
1069 }
1070 }
1071
1072 _short_lived_surv_rate_group->start_adding_regions();
1073 // do that for any other surv rate groupsx
1074
1075 if (update_stats) {
1076 double cost_per_card_ms = 0.0;
1077 if (_pending_cards > 0) {
1078 cost_per_card_ms = phase_times()->average_last_update_rs_time() / (double) _pending_cards;
1079 _cost_per_card_ms_seq->add(cost_per_card_ms);
1080 }
1081
1082 size_t cards_scanned = _g1->cards_scanned();
1083
1084 double cost_per_entry_ms = 0.0;
1085 if (cards_scanned > 10) {
1086 cost_per_entry_ms = phase_times()->average_last_scan_rs_time() / (double) cards_scanned;
1087 if (_last_gc_was_young) {
1088 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1089 } else {
1090 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1091 }
1092 }
1093
1094 if (_max_rs_lengths > 0) {
1095 double cards_per_entry_ratio =
1096 (double) cards_scanned / (double) _max_rs_lengths;
1097 if (_last_gc_was_young) {
1098 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1099 } else {
1100 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1101 }
1102 }
1103
1104 // This is defensive. For a while _max_rs_lengths could get
1105 // smaller than _recorded_rs_lengths which was causing
1106 // rs_length_diff to get very large and mess up the RSet length
1107 // predictions. The reason was unsafe concurrent updates to the
1108 // _inc_cset_recorded_rs_lengths field which the code below guards
1109 // against (see CR 7118202). This bug has now been fixed (see CR
1110 // 7119027). However, I'm still worried that
1111 // _inc_cset_recorded_rs_lengths might still end up somewhat
1112 // inaccurate. The concurrent refinement thread calculates an
1113 // RSet's length concurrently with other CR threads updating it
1114 // which might cause it to calculate the length incorrectly (if,
1115 // say, it's in mid-coarsening). So I'll leave in the defensive
1116 // conditional below just in case.
1117 size_t rs_length_diff = 0;
1118 if (_max_rs_lengths > _recorded_rs_lengths) {
1119 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1120 }
1121 _rs_length_diff_seq->add((double) rs_length_diff);
1122
1123 size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1124 size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1125 double cost_per_byte_ms = 0.0;
1126
1127 if (copied_bytes > 0) {
1128 cost_per_byte_ms = phase_times()->average_last_obj_copy_time() / (double) copied_bytes;
1129 if (_in_marking_window) {
1130 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1131 } else {
1132 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1133 }
1134 }
1135
1136 double all_other_time_ms = pause_time_ms -
1137 (phase_times()->average_last_update_rs_time() + phase_times()->average_last_scan_rs_time()
1138 + phase_times()->average_last_obj_copy_time() + phase_times()->average_last_termination_time());
1139
1140 double young_other_time_ms = 0.0;
1141 if (young_cset_region_length() > 0) {
1142 young_other_time_ms =
1143 phase_times()->young_cset_choice_time_ms() +
1144 phase_times()->young_free_cset_time_ms();
1145 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1146 (double) young_cset_region_length());
1147 }
1148 double non_young_other_time_ms = 0.0;
1149 if (old_cset_region_length() > 0) {
1150 non_young_other_time_ms =
1151 phase_times()->non_young_cset_choice_time_ms() +
1152 phase_times()->non_young_free_cset_time_ms();
1153
1154 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1155 (double) old_cset_region_length());
1156 }
1157
1158 double constant_other_time_ms = all_other_time_ms -
1159 (young_other_time_ms + non_young_other_time_ms);
1160 _constant_other_time_ms_seq->add(constant_other_time_ms);
1161
1162 double survival_ratio = 0.0;
1163 if (_collection_set_bytes_used_before > 0) {
1164 survival_ratio = (double) _bytes_copied_during_gc /
1165 (double) _collection_set_bytes_used_before;
1166 }
1167
1168 _pending_cards_seq->add((double) _pending_cards);
1169 _rs_lengths_seq->add((double) _max_rs_lengths);
1170 }
1171
1172 _in_marking_window = new_in_marking_window;
1173 _in_marking_window_im = new_in_marking_window_im;
1174 _free_regions_at_end_of_collection = _g1->free_regions();
1175 update_young_list_target_length();
1176
1177 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1178 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1179 adjust_concurrent_refinement(phase_times()->average_last_update_rs_time(),
1180 phase_times()->sum_last_update_rs_processed_buffers(), update_rs_time_goal_ms);
1181
1182 _collectionSetChooser->verify();
1183 }
1184
1185 #define EXT_SIZE_FORMAT "%.1f%s"
1186 #define EXT_SIZE_PARAMS(bytes) \
1187 byte_size_in_proper_unit((double)(bytes)), \
1188 proper_unit_for_byte_size((bytes))
1189
1190 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1191 YoungList* young_list = _g1->young_list();
1192 _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1193 _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1194 _heap_capacity_bytes_before_gc = _g1->capacity();
1195 _heap_used_bytes_before_gc = _g1->used();
1196 _cur_collection_pause_used_regions_at_start = _g1->used_regions();
1197
1198 _eden_capacity_bytes_before_gc =
1199 (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1200
1201 if (full) {
1202 _metaspace_used_bytes_before_gc = MetaspaceAux::allocated_used_bytes();
1203 }
1204 }
1205
1206 void G1CollectorPolicy::print_heap_transition() {
1207 _g1->print_size_transition(gclog_or_tty,
1208 _heap_used_bytes_before_gc,
1209 _g1->used(),
1210 _g1->capacity());
1211 }
1212
1213 void G1CollectorPolicy::print_detailed_heap_transition(bool full) {
1214 YoungList* young_list = _g1->young_list();
1215
1216 size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1217 size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1218 size_t heap_used_bytes_after_gc = _g1->used();
1219
1220 size_t heap_capacity_bytes_after_gc = _g1->capacity();
1221 size_t eden_capacity_bytes_after_gc =
1222 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1223
1224 gclog_or_tty->print(
1225 " [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
1226 "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1227 "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
1228 EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
1229 EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1230 EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1231 EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1232 EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1233 EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1234 EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1235 EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1236 EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1237 EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1238 EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1239
1240 if (full) {
1241 MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1242 }
1243
1244 gclog_or_tty->cr();
1245 }
1246
1247 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1248 double update_rs_processed_buffers,
1249 double goal_ms) {
1250 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1251 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1252
1253 if (G1UseAdaptiveConcRefinement) {
1254 const int k_gy = 3, k_gr = 6;
1255 const double inc_k = 1.1, dec_k = 0.9;
1256
1257 int g = cg1r->green_zone();
1258 if (update_rs_time > goal_ms) {
1259 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1260 } else {
1261 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1262 g = (int)MAX2(g * inc_k, g + 1.0);
1263 }
1264 }
1265 // Change the refinement threads params
1266 cg1r->set_green_zone(g);
1267 cg1r->set_yellow_zone(g * k_gy);
1268 cg1r->set_red_zone(g * k_gr);
1269 cg1r->reinitialize_threads();
1270
1271 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1272 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1273 cg1r->yellow_zone());
1274 // Change the barrier params
1275 dcqs.set_process_completed_threshold(processing_threshold);
1276 dcqs.set_max_completed_queue(cg1r->red_zone());
1277 }
1278
1279 int curr_queue_size = dcqs.completed_buffers_num();
1280 if (curr_queue_size >= cg1r->yellow_zone()) {
1281 dcqs.set_completed_queue_padding(curr_queue_size);
1282 } else {
1283 dcqs.set_completed_queue_padding(0);
1284 }
1285 dcqs.notify_if_necessary();
1286 }
1287
1288 double
1289 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1290 size_t scanned_cards) {
1291 return
1292 predict_rs_update_time_ms(pending_cards) +
1293 predict_rs_scan_time_ms(scanned_cards) +
1294 predict_constant_other_time_ms();
1295 }
1296
1297 double
1298 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1299 size_t rs_length = predict_rs_length_diff();
1300 size_t card_num;
1301 if (gcs_are_young()) {
1302 card_num = predict_young_card_num(rs_length);
1303 } else {
1304 card_num = predict_non_young_card_num(rs_length);
1305 }
1306 return predict_base_elapsed_time_ms(pending_cards, card_num);
1307 }
1308
1309 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1310 size_t bytes_to_copy;
1311 if (hr->is_marked())
1312 bytes_to_copy = hr->max_live_bytes();
1313 else {
1314 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1315 int age = hr->age_in_surv_rate_group();
1316 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1317 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1318 }
1319 return bytes_to_copy;
1320 }
1321
1322 double
1323 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1324 bool for_young_gc) {
1325 size_t rs_length = hr->rem_set()->occupied();
1326 size_t card_num;
1327
1328 // Predicting the number of cards is based on which type of GC
1329 // we're predicting for.
1330 if (for_young_gc) {
1331 card_num = predict_young_card_num(rs_length);
1332 } else {
1333 card_num = predict_non_young_card_num(rs_length);
1334 }
1335 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1336
1337 double region_elapsed_time_ms =
1338 predict_rs_scan_time_ms(card_num) +
1339 predict_object_copy_time_ms(bytes_to_copy);
1340
1341 // The prediction of the "other" time for this region is based
1342 // upon the region type and NOT the GC type.
1343 if (hr->is_young()) {
1344 region_elapsed_time_ms += predict_young_other_time_ms(1);
1345 } else {
1346 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1347 }
1348 return region_elapsed_time_ms;
1349 }
1350
1351 void
1352 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1353 uint survivor_cset_region_length) {
1354 _eden_cset_region_length = eden_cset_region_length;
1355 _survivor_cset_region_length = survivor_cset_region_length;
1356 _old_cset_region_length = 0;
1357 }
1358
1359 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1360 _recorded_rs_lengths = rs_lengths;
1361 }
1362
1363 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1364 double elapsed_ms) {
1365 _recent_gc_times_ms->add(elapsed_ms);
1366 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1367 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1368 }
1369
1370 size_t G1CollectorPolicy::expansion_amount() {
1371 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1372 double threshold = _gc_overhead_perc;
1373 if (recent_gc_overhead > threshold) {
1374 // We will double the existing space, or take
1375 // G1ExpandByPercentOfAvailable % of the available expansion
1376 // space, whichever is smaller, bounded below by a minimum
1377 // expansion (unless that's all that's left.)
1378 const size_t min_expand_bytes = 1*M;
1379 size_t reserved_bytes = _g1->max_capacity();
1380 size_t committed_bytes = _g1->capacity();
1381 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1382 size_t expand_bytes;
1383 size_t expand_bytes_via_pct =
1384 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1385 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1386 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1387 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1388
1389 ergo_verbose5(ErgoHeapSizing,
1390 "attempt heap expansion",
1391 ergo_format_reason("recent GC overhead higher than "
1392 "threshold after GC")
1393 ergo_format_perc("recent GC overhead")
1394 ergo_format_perc("threshold")
1395 ergo_format_byte("uncommitted")
1396 ergo_format_byte_perc("calculated expansion amount"),
1397 recent_gc_overhead, threshold,
1398 uncommitted_bytes,
1399 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1400
1401 return expand_bytes;
1402 } else {
1403 return 0;
1404 }
1405 }
1406
1407 void G1CollectorPolicy::print_tracing_info() const {
1408 _trace_gen0_time_data.print();
1409 _trace_gen1_time_data.print();
1410 }
1411
1412 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1413 #ifndef PRODUCT
1414 _short_lived_surv_rate_group->print_surv_rate_summary();
1415 // add this call for any other surv rate groups
1416 #endif // PRODUCT
1417 }
1418
1419 uint G1CollectorPolicy::max_regions(int purpose) {
1420 switch (purpose) {
1421 case GCAllocForSurvived:
1422 return _max_survivor_regions;
1423 case GCAllocForTenured:
1424 return REGIONS_UNLIMITED;
1425 default:
1426 ShouldNotReachHere();
1427 return REGIONS_UNLIMITED;
1428 };
1429 }
1430
1431 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1432 uint expansion_region_num = 0;
1433 if (GCLockerEdenExpansionPercent > 0) {
1434 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1435 double expansion_region_num_d = perc * (double) _young_list_target_length;
1436 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1437 // less than 1.0) we'll get 1.
1438 expansion_region_num = (uint) ceil(expansion_region_num_d);
1439 } else {
1440 assert(expansion_region_num == 0, "sanity");
1441 }
1442 _young_list_max_length = _young_list_target_length + expansion_region_num;
1443 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1444 }
1445
1446 // Calculates survivor space parameters.
1447 void G1CollectorPolicy::update_survivors_policy() {
1448 double max_survivor_regions_d =
1449 (double) _young_list_target_length / (double) SurvivorRatio;
1450 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1451 // smaller than 1.0) we'll get 1.
1452 _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1453
1454 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1455 HeapRegion::GrainWords * _max_survivor_regions);
1456 }
1457
1458 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
1459 GCCause::Cause gc_cause) {
1460 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1461 if (!during_cycle) {
1462 ergo_verbose1(ErgoConcCycles,
1463 "request concurrent cycle initiation",
1464 ergo_format_reason("requested by GC cause")
1465 ergo_format_str("GC cause"),
1466 GCCause::to_string(gc_cause));
1467 set_initiate_conc_mark_if_possible();
1468 return true;
1469 } else {
1470 ergo_verbose1(ErgoConcCycles,
1471 "do not request concurrent cycle initiation",
1472 ergo_format_reason("concurrent cycle already in progress")
1473 ergo_format_str("GC cause"),
1474 GCCause::to_string(gc_cause));
1475 return false;
1476 }
1477 }
1478
1479 void
1480 G1CollectorPolicy::decide_on_conc_mark_initiation() {
1481 // We are about to decide on whether this pause will be an
1482 // initial-mark pause.
1483
1484 // First, during_initial_mark_pause() should not be already set. We
1485 // will set it here if we have to. However, it should be cleared by
1486 // the end of the pause (it's only set for the duration of an
1487 // initial-mark pause).
1488 assert(!during_initial_mark_pause(), "pre-condition");
1489
1490 if (initiate_conc_mark_if_possible()) {
1491 // We had noticed on a previous pause that the heap occupancy has
1492 // gone over the initiating threshold and we should start a
1493 // concurrent marking cycle. So we might initiate one.
1494
1495 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1496 if (!during_cycle) {
1497 // The concurrent marking thread is not "during a cycle", i.e.,
1498 // it has completed the last one. So we can go ahead and
1499 // initiate a new cycle.
1500
1501 set_during_initial_mark_pause();
1502 // We do not allow mixed GCs during marking.
1503 if (!gcs_are_young()) {
1504 set_gcs_are_young(true);
1505 ergo_verbose0(ErgoMixedGCs,
1506 "end mixed GCs",
1507 ergo_format_reason("concurrent cycle is about to start"));
1508 }
1509
1510 // And we can now clear initiate_conc_mark_if_possible() as
1511 // we've already acted on it.
1512 clear_initiate_conc_mark_if_possible();
1513
1514 ergo_verbose0(ErgoConcCycles,
1515 "initiate concurrent cycle",
1516 ergo_format_reason("concurrent cycle initiation requested"));
1517 } else {
1518 // The concurrent marking thread is still finishing up the
1519 // previous cycle. If we start one right now the two cycles
1520 // overlap. In particular, the concurrent marking thread might
1521 // be in the process of clearing the next marking bitmap (which
1522 // we will use for the next cycle if we start one). Starting a
1523 // cycle now will be bad given that parts of the marking
1524 // information might get cleared by the marking thread. And we
1525 // cannot wait for the marking thread to finish the cycle as it
1526 // periodically yields while clearing the next marking bitmap
1527 // and, if it's in a yield point, it's waiting for us to
1528 // finish. So, at this point we will not start a cycle and we'll
1529 // let the concurrent marking thread complete the last one.
1530 ergo_verbose0(ErgoConcCycles,
1531 "do not initiate concurrent cycle",
1532 ergo_format_reason("concurrent cycle already in progress"));
1533 }
1534 }
1535 }
1536
1537 class KnownGarbageClosure: public HeapRegionClosure {
1538 G1CollectedHeap* _g1h;
1539 CollectionSetChooser* _hrSorted;
1540
1541 public:
1542 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
1543 _g1h(G1CollectedHeap::heap()), _hrSorted(hrSorted) { }
1544
1545 bool doHeapRegion(HeapRegion* r) {
1546 // We only include humongous regions in collection
1547 // sets when concurrent mark shows that their contained object is
1548 // unreachable.
1549
1550 // Do we have any marking information for this region?
1551 if (r->is_marked()) {
1552 // We will skip any region that's currently used as an old GC
1553 // alloc region (we should not consider those for collection
1554 // before we fill them up).
1555 if (_hrSorted->should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1556 _hrSorted->add_region(r);
1557 }
1558 }
1559 return false;
1560 }
1561 };
1562
1563 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1564 G1CollectedHeap* _g1h;
1565 CSetChooserParUpdater _cset_updater;
1566
1567 public:
1568 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1569 uint chunk_size) :
1570 _g1h(G1CollectedHeap::heap()),
1571 _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1572
1573 bool doHeapRegion(HeapRegion* r) {
1574 // Do we have any marking information for this region?
1575 if (r->is_marked()) {
1576 // We will skip any region that's currently used as an old GC
1577 // alloc region (we should not consider those for collection
1578 // before we fill them up).
1579 if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1580 _cset_updater.add_region(r);
1581 }
1582 }
1583 return false;
1584 }
1585 };
1586
1587 class ParKnownGarbageTask: public AbstractGangTask {
1588 CollectionSetChooser* _hrSorted;
1589 uint _chunk_size;
1590 G1CollectedHeap* _g1;
1591 public:
1592 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size) :
1593 AbstractGangTask("ParKnownGarbageTask"),
1594 _hrSorted(hrSorted), _chunk_size(chunk_size),
1595 _g1(G1CollectedHeap::heap()) { }
1596
1597 void work(uint worker_id) {
1598 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1599
1600 // Back to zero for the claim value.
1601 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, worker_id,
1602 _g1->workers()->active_workers(),
1603 HeapRegion::InitialClaimValue);
1604 }
1605 };
1606
1607 void
1608 G1CollectorPolicy::record_concurrent_mark_cleanup_end(int no_of_gc_threads) {
1609 _collectionSetChooser->clear();
1610
1611 uint region_num = _g1->n_regions();
1612 if (G1CollectedHeap::use_parallel_gc_threads()) {
1613 const uint OverpartitionFactor = 4;
1614 uint WorkUnit;
1615 // The use of MinChunkSize = 8 in the original code
1616 // causes some assertion failures when the total number of
1617 // region is less than 8. The code here tries to fix that.
1618 // Should the original code also be fixed?
1619 if (no_of_gc_threads > 0) {
1620 const uint MinWorkUnit = MAX2(region_num / no_of_gc_threads, 1U);
1621 WorkUnit = MAX2(region_num / (no_of_gc_threads * OverpartitionFactor),
1622 MinWorkUnit);
1623 } else {
1624 assert(no_of_gc_threads > 0,
1625 "The active gc workers should be greater than 0");
1626 // In a product build do something reasonable to avoid a crash.
1627 const uint MinWorkUnit = MAX2(region_num / (uint) ParallelGCThreads, 1U);
1628 WorkUnit =
1629 MAX2(region_num / (uint) (ParallelGCThreads * OverpartitionFactor),
1630 MinWorkUnit);
1631 }
1632 _collectionSetChooser->prepare_for_par_region_addition(_g1->n_regions(),
1633 WorkUnit);
1634 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
1635 (int) WorkUnit);
1636 _g1->workers()->run_task(&parKnownGarbageTask);
1637
1638 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
1639 "sanity check");
1640 } else {
1641 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
1642 _g1->heap_region_iterate(&knownGarbagecl);
1643 }
1644
1645 _collectionSetChooser->sort_regions();
1646
1647 double end_sec = os::elapsedTime();
1648 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1649 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1650 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1651 _prev_collection_pause_end_ms += elapsed_time_ms;
1652 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true);
1653 }
1654
1655 // Add the heap region at the head of the non-incremental collection set
1656 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1657 assert(_inc_cset_build_state == Active, "Precondition");
1658 assert(!hr->is_young(), "non-incremental add of young region");
1659
1660 assert(!hr->in_collection_set(), "should not already be in the CSet");
1661 hr->set_in_collection_set(true);
1662 hr->set_next_in_collection_set(_collection_set);
1663 _collection_set = hr;
1664 _collection_set_bytes_used_before += hr->used();
1665 _g1->register_region_with_in_cset_fast_test(hr);
1666 size_t rs_length = hr->rem_set()->occupied();
1667 _recorded_rs_lengths += rs_length;
1668 _old_cset_region_length += 1;
1669 }
1670
1671 // Initialize the per-collection-set information
1672 void G1CollectorPolicy::start_incremental_cset_building() {
1673 assert(_inc_cset_build_state == Inactive, "Precondition");
1674
1675 _inc_cset_head = NULL;
1676 _inc_cset_tail = NULL;
1677 _inc_cset_bytes_used_before = 0;
1678
1679 _inc_cset_max_finger = 0;
1680 _inc_cset_recorded_rs_lengths = 0;
1681 _inc_cset_recorded_rs_lengths_diffs = 0;
1682 _inc_cset_predicted_elapsed_time_ms = 0.0;
1683 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1684 _inc_cset_build_state = Active;
1685 }
1686
1687 void G1CollectorPolicy::finalize_incremental_cset_building() {
1688 assert(_inc_cset_build_state == Active, "Precondition");
1689 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1690
1691 // The two "main" fields, _inc_cset_recorded_rs_lengths and
1692 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1693 // that adds a new region to the CSet. Further updates by the
1694 // concurrent refinement thread that samples the young RSet lengths
1695 // are accumulated in the *_diffs fields. Here we add the diffs to
1696 // the "main" fields.
1697
1698 if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1699 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1700 } else {
1701 // This is defensive. The diff should in theory be always positive
1702 // as RSets can only grow between GCs. However, given that we
1703 // sample their size concurrently with other threads updating them
1704 // it's possible that we might get the wrong size back, which
1705 // could make the calculations somewhat inaccurate.
1706 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1707 if (_inc_cset_recorded_rs_lengths >= diffs) {
1708 _inc_cset_recorded_rs_lengths -= diffs;
1709 } else {
1710 _inc_cset_recorded_rs_lengths = 0;
1711 }
1712 }
1713 _inc_cset_predicted_elapsed_time_ms +=
1714 _inc_cset_predicted_elapsed_time_ms_diffs;
1715
1716 _inc_cset_recorded_rs_lengths_diffs = 0;
1717 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1718 }
1719
1720 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1721 // This routine is used when:
1722 // * adding survivor regions to the incremental cset at the end of an
1723 // evacuation pause,
1724 // * adding the current allocation region to the incremental cset
1725 // when it is retired, and
1726 // * updating existing policy information for a region in the
1727 // incremental cset via young list RSet sampling.
1728 // Therefore this routine may be called at a safepoint by the
1729 // VM thread, or in-between safepoints by mutator threads (when
1730 // retiring the current allocation region) or a concurrent
1731 // refine thread (RSet sampling).
1732
1733 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1734 size_t used_bytes = hr->used();
1735 _inc_cset_recorded_rs_lengths += rs_length;
1736 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1737 _inc_cset_bytes_used_before += used_bytes;
1738
1739 // Cache the values we have added to the aggregated informtion
1740 // in the heap region in case we have to remove this region from
1741 // the incremental collection set, or it is updated by the
1742 // rset sampling code
1743 hr->set_recorded_rs_length(rs_length);
1744 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1745 }
1746
1747 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1748 size_t new_rs_length) {
1749 // Update the CSet information that is dependent on the new RS length
1750 assert(hr->is_young(), "Precondition");
1751 assert(!SafepointSynchronize::is_at_safepoint(),
1752 "should not be at a safepoint");
1753
1754 // We could have updated _inc_cset_recorded_rs_lengths and
1755 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1756 // that atomically, as this code is executed by a concurrent
1757 // refinement thread, potentially concurrently with a mutator thread
1758 // allocating a new region and also updating the same fields. To
1759 // avoid the atomic operations we accumulate these updates on two
1760 // separate fields (*_diffs) and we'll just add them to the "main"
1761 // fields at the start of a GC.
1762
1763 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1764 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1765 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1766
1767 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1768 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
1769 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1770 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1771
1772 hr->set_recorded_rs_length(new_rs_length);
1773 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1774 }
1775
1776 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1777 assert(hr->is_young(), "invariant");
1778 assert(hr->young_index_in_cset() > -1, "should have already been set");
1779 assert(_inc_cset_build_state == Active, "Precondition");
1780
1781 // We need to clear and set the cached recorded/cached collection set
1782 // information in the heap region here (before the region gets added
1783 // to the collection set). An individual heap region's cached values
1784 // are calculated, aggregated with the policy collection set info,
1785 // and cached in the heap region here (initially) and (subsequently)
1786 // by the Young List sampling code.
1787
1788 size_t rs_length = hr->rem_set()->occupied();
1789 add_to_incremental_cset_info(hr, rs_length);
1790
1791 HeapWord* hr_end = hr->end();
1792 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1793
1794 assert(!hr->in_collection_set(), "invariant");
1795 hr->set_in_collection_set(true);
1796 assert( hr->next_in_collection_set() == NULL, "invariant");
1797
1798 _g1->register_region_with_in_cset_fast_test(hr);
1799 }
1800
1801 // Add the region at the RHS of the incremental cset
1802 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1803 // We should only ever be appending survivors at the end of a pause
1804 assert( hr->is_survivor(), "Logic");
1805
1806 // Do the 'common' stuff
1807 add_region_to_incremental_cset_common(hr);
1808
1809 // Now add the region at the right hand side
1810 if (_inc_cset_tail == NULL) {
1811 assert(_inc_cset_head == NULL, "invariant");
1812 _inc_cset_head = hr;
1813 } else {
1814 _inc_cset_tail->set_next_in_collection_set(hr);
1815 }
1816 _inc_cset_tail = hr;
1817 }
1818
1819 // Add the region to the LHS of the incremental cset
1820 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1821 // Survivors should be added to the RHS at the end of a pause
1822 assert(!hr->is_survivor(), "Logic");
1823
1824 // Do the 'common' stuff
1825 add_region_to_incremental_cset_common(hr);
1826
1827 // Add the region at the left hand side
1828 hr->set_next_in_collection_set(_inc_cset_head);
1829 if (_inc_cset_head == NULL) {
1830 assert(_inc_cset_tail == NULL, "Invariant");
1831 _inc_cset_tail = hr;
1832 }
1833 _inc_cset_head = hr;
1834 }
1835
1836 #ifndef PRODUCT
1837 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1838 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1839
1840 st->print_cr("\nCollection_set:");
1841 HeapRegion* csr = list_head;
1842 while (csr != NULL) {
1843 HeapRegion* next = csr->next_in_collection_set();
1844 assert(csr->in_collection_set(), "bad CS");
1845 st->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
1846 HR_FORMAT_PARAMS(csr),
1847 csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(),
1848 csr->age_in_surv_rate_group_cond());
1849 csr = next;
1850 }
1851 }
1852 #endif // !PRODUCT
1853
1854 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) {
1855 // Returns the given amount of reclaimable bytes (that represents
1856 // the amount of reclaimable space still to be collected) as a
1857 // percentage of the current heap capacity.
1858 size_t capacity_bytes = _g1->capacity();
1859 return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1860 }
1861
1862 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1863 const char* false_action_str) {
1864 CollectionSetChooser* cset_chooser = _collectionSetChooser;
1865 if (cset_chooser->is_empty()) {
1866 ergo_verbose0(ErgoMixedGCs,
1867 false_action_str,
1868 ergo_format_reason("candidate old regions not available"));
1869 return false;
1870 }
1871
1872 // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1873 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1874 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1875 double threshold = (double) G1HeapWastePercent;
1876 if (reclaimable_perc <= threshold) {
1877 ergo_verbose4(ErgoMixedGCs,
1878 false_action_str,
1879 ergo_format_reason("reclaimable percentage not over threshold")
1880 ergo_format_region("candidate old regions")
1881 ergo_format_byte_perc("reclaimable")
1882 ergo_format_perc("threshold"),
1883 cset_chooser->remaining_regions(),
1884 reclaimable_bytes,
1885 reclaimable_perc, threshold);
1886 return false;
1887 }
1888
1889 ergo_verbose4(ErgoMixedGCs,
1890 true_action_str,
1891 ergo_format_reason("candidate old regions available")
1892 ergo_format_region("candidate old regions")
1893 ergo_format_byte_perc("reclaimable")
1894 ergo_format_perc("threshold"),
1895 cset_chooser->remaining_regions(),
1896 reclaimable_bytes,
1897 reclaimable_perc, threshold);
1898 return true;
1899 }
1900
1901 uint G1CollectorPolicy::calc_min_old_cset_length() {
1902 // The min old CSet region bound is based on the maximum desired
1903 // number of mixed GCs after a cycle. I.e., even if some old regions
1904 // look expensive, we should add them to the CSet anyway to make
1905 // sure we go through the available old regions in no more than the
1906 // maximum desired number of mixed GCs.
1907 //
1908 // The calculation is based on the number of marked regions we added
1909 // to the CSet chooser in the first place, not how many remain, so
1910 // that the result is the same during all mixed GCs that follow a cycle.
1911
1912 const size_t region_num = (size_t) _collectionSetChooser->length();
1913 const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
1914 size_t result = region_num / gc_num;
1915 // emulate ceiling
1916 if (result * gc_num < region_num) {
1917 result += 1;
1918 }
1919 return (uint) result;
1920 }
1921
1922 uint G1CollectorPolicy::calc_max_old_cset_length() {
1923 // The max old CSet region bound is based on the threshold expressed
1924 // as a percentage of the heap size. I.e., it should bound the
1925 // number of old regions added to the CSet irrespective of how many
1926 // of them are available.
1927
1928 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1929 const size_t region_num = g1h->n_regions();
1930 const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
1931 size_t result = region_num * perc / 100;
1932 // emulate ceiling
1933 if (100 * result < region_num * perc) {
1934 result += 1;
1935 }
1936 return (uint) result;
1937 }
1938
1939
1940 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info) {
1941 double young_start_time_sec = os::elapsedTime();
1942
1943 YoungList* young_list = _g1->young_list();
1944 finalize_incremental_cset_building();
1945
1946 guarantee(target_pause_time_ms > 0.0,
1947 err_msg("target_pause_time_ms = %1.6lf should be positive",
1948 target_pause_time_ms));
1949 guarantee(_collection_set == NULL, "Precondition");
1950
1951 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
1952 double predicted_pause_time_ms = base_time_ms;
1953 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
1954
1955 ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
1956 "start choosing CSet",
1957 ergo_format_size("_pending_cards")
1958 ergo_format_ms("predicted base time")
1959 ergo_format_ms("remaining time")
1960 ergo_format_ms("target pause time"),
1961 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
1962
1963 _last_gc_was_young = gcs_are_young() ? true : false;
1964
1965 if (_last_gc_was_young) {
1966 _trace_gen0_time_data.increment_young_collection_count();
1967 } else {
1968 _trace_gen0_time_data.increment_mixed_collection_count();
1969 }
1970
1971 // The young list is laid with the survivor regions from the previous
1972 // pause are appended to the RHS of the young list, i.e.
1973 // [Newly Young Regions ++ Survivors from last pause].
1974
1975 uint survivor_region_length = young_list->survivor_length();
1976 uint eden_region_length = young_list->length() - survivor_region_length;
1977 init_cset_region_lengths(eden_region_length, survivor_region_length);
1978
1979 HeapRegion* hr = young_list->first_survivor_region();
1980 while (hr != NULL) {
1981 assert(hr->is_survivor(), "badly formed young list");
1982 hr->set_young();
1983 hr = hr->get_next_young_region();
1984 }
1985
1986 // Clear the fields that point to the survivor list - they are all young now.
1987 young_list->clear_survivors();
1988
1989 _collection_set = _inc_cset_head;
1990 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
1991 time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
1992 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
1993
1994 ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
1995 "add young regions to CSet",
1996 ergo_format_region("eden")
1997 ergo_format_region("survivors")
1998 ergo_format_ms("predicted young region time"),
1999 eden_region_length, survivor_region_length,
2000 _inc_cset_predicted_elapsed_time_ms);
2001
2002 // The number of recorded young regions is the incremental
2003 // collection set's current size
2004 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2005
2006 double young_end_time_sec = os::elapsedTime();
2007 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
2008
2009 // Set the start of the non-young choice time.
2010 double non_young_start_time_sec = young_end_time_sec;
2011
2012 if (!gcs_are_young()) {
2013 CollectionSetChooser* cset_chooser = _collectionSetChooser;
2014 cset_chooser->verify();
2015 const uint min_old_cset_length = calc_min_old_cset_length();
2016 const uint max_old_cset_length = calc_max_old_cset_length();
2017
2018 uint expensive_region_num = 0;
2019 bool check_time_remaining = adaptive_young_list_length();
2020
2021 HeapRegion* hr = cset_chooser->peek();
2022 while (hr != NULL) {
2023 if (old_cset_region_length() >= max_old_cset_length) {
2024 // Added maximum number of old regions to the CSet.
2025 ergo_verbose2(ErgoCSetConstruction,
2026 "finish adding old regions to CSet",
2027 ergo_format_reason("old CSet region num reached max")
2028 ergo_format_region("old")
2029 ergo_format_region("max"),
2030 old_cset_region_length(), max_old_cset_length);
2031 break;
2032 }
2033
2034
2035 // Stop adding regions if the remaining reclaimable space is
2036 // not above G1HeapWastePercent.
2037 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
2038 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
2039 double threshold = (double) G1HeapWastePercent;
2040 if (reclaimable_perc <= threshold) {
2041 // We've added enough old regions that the amount of uncollected
2042 // reclaimable space is at or below the waste threshold. Stop
2043 // adding old regions to the CSet.
2044 ergo_verbose5(ErgoCSetConstruction,
2045 "finish adding old regions to CSet",
2046 ergo_format_reason("reclaimable percentage not over threshold")
2047 ergo_format_region("old")
2048 ergo_format_region("max")
2049 ergo_format_byte_perc("reclaimable")
2050 ergo_format_perc("threshold"),
2051 old_cset_region_length(),
2052 max_old_cset_length,
2053 reclaimable_bytes,
2054 reclaimable_perc, threshold);
2055 break;
2056 }
2057
2058 double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
2059 if (check_time_remaining) {
2060 if (predicted_time_ms > time_remaining_ms) {
2061 // Too expensive for the current CSet.
2062
2063 if (old_cset_region_length() >= min_old_cset_length) {
2064 // We have added the minimum number of old regions to the CSet,
2065 // we are done with this CSet.
2066 ergo_verbose4(ErgoCSetConstruction,
2067 "finish adding old regions to CSet",
2068 ergo_format_reason("predicted time is too high")
2069 ergo_format_ms("predicted time")
2070 ergo_format_ms("remaining time")
2071 ergo_format_region("old")
2072 ergo_format_region("min"),
2073 predicted_time_ms, time_remaining_ms,
2074 old_cset_region_length(), min_old_cset_length);
2075 break;
2076 }
2077
2078 // We'll add it anyway given that we haven't reached the
2079 // minimum number of old regions.
2080 expensive_region_num += 1;
2081 }
2082 } else {
2083 if (old_cset_region_length() >= min_old_cset_length) {
2084 // In the non-auto-tuning case, we'll finish adding regions
2085 // to the CSet if we reach the minimum.
2086 ergo_verbose2(ErgoCSetConstruction,
2087 "finish adding old regions to CSet",
2088 ergo_format_reason("old CSet region num reached min")
2089 ergo_format_region("old")
2090 ergo_format_region("min"),
2091 old_cset_region_length(), min_old_cset_length);
2092 break;
2093 }
2094 }
2095
2096 // We will add this region to the CSet.
2097 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2098 predicted_pause_time_ms += predicted_time_ms;
2099 cset_chooser->remove_and_move_to_next(hr);
2100 _g1->old_set_remove(hr);
2101 add_old_region_to_cset(hr);
2102
2103 hr = cset_chooser->peek();
2104 }
2105 if (hr == NULL) {
2106 ergo_verbose0(ErgoCSetConstruction,
2107 "finish adding old regions to CSet",
2108 ergo_format_reason("candidate old regions not available"));
2109 }
2110
2111 if (expensive_region_num > 0) {
2112 // We print the information once here at the end, predicated on
2113 // whether we added any apparently expensive regions or not, to
2114 // avoid generating output per region.
2115 ergo_verbose4(ErgoCSetConstruction,
2116 "added expensive regions to CSet",
2117 ergo_format_reason("old CSet region num not reached min")
2118 ergo_format_region("old")
2119 ergo_format_region("expensive")
2120 ergo_format_region("min")
2121 ergo_format_ms("remaining time"),
2122 old_cset_region_length(),
2123 expensive_region_num,
2124 min_old_cset_length,
2125 time_remaining_ms);
2126 }
2127
2128 cset_chooser->verify();
2129 }
2130
2131 stop_incremental_cset_building();
2132
2133 ergo_verbose5(ErgoCSetConstruction,
2134 "finish choosing CSet",
2135 ergo_format_region("eden")
2136 ergo_format_region("survivors")
2137 ergo_format_region("old")
2138 ergo_format_ms("predicted pause time")
2139 ergo_format_ms("target pause time"),
2140 eden_region_length, survivor_region_length,
2141 old_cset_region_length(),
2142 predicted_pause_time_ms, target_pause_time_ms);
2143
2144 double non_young_end_time_sec = os::elapsedTime();
2145 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2146 evacuation_info.set_collectionset_regions(cset_region_length());
2147 }
2148
2149 void TraceGen0TimeData::record_start_collection(double time_to_stop_the_world_ms) {
2150 if(TraceGen0Time) {
2151 _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2152 }
2153 }
2154
2155 void TraceGen0TimeData::record_yield_time(double yield_time_ms) {
2156 if(TraceGen0Time) {
2157 _all_yield_times_ms.add(yield_time_ms);
2158 }
2159 }
2160
2161 void TraceGen0TimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2162 if(TraceGen0Time) {
2163 _total.add(pause_time_ms);
2164 _other.add(pause_time_ms - phase_times->accounted_time_ms());
2165 _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2166 _parallel.add(phase_times->cur_collection_par_time_ms());
2167 _ext_root_scan.add(phase_times->average_last_ext_root_scan_time());
2168 _satb_filtering.add(phase_times->average_last_satb_filtering_times_ms());
2169 _update_rs.add(phase_times->average_last_update_rs_time());
2170 _scan_rs.add(phase_times->average_last_scan_rs_time());
2171 _obj_copy.add(phase_times->average_last_obj_copy_time());
2172 _termination.add(phase_times->average_last_termination_time());
2173
2174 double parallel_known_time = phase_times->average_last_ext_root_scan_time() +
2175 phase_times->average_last_satb_filtering_times_ms() +
2176 phase_times->average_last_update_rs_time() +
2177 phase_times->average_last_scan_rs_time() +
2178 phase_times->average_last_obj_copy_time() +
2179 + phase_times->average_last_termination_time();
2180
2181 double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2182 _parallel_other.add(parallel_other_time);
2183 _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2184 }
2185 }
2186
2187 void TraceGen0TimeData::increment_young_collection_count() {
2188 if(TraceGen0Time) {
2189 ++_young_pause_num;
2190 }
2191 }
2192
2193 void TraceGen0TimeData::increment_mixed_collection_count() {
2194 if(TraceGen0Time) {
2195 ++_mixed_pause_num;
2196 }
2197 }
2198
2199 void TraceGen0TimeData::print_summary(const char* str,
2200 const NumberSeq* seq) const {
2201 double sum = seq->sum();
2202 gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2203 str, sum / 1000.0, seq->avg());
2204 }
2205
2206 void TraceGen0TimeData::print_summary_sd(const char* str,
2207 const NumberSeq* seq) const {
2208 print_summary(str, seq);
2209 gclog_or_tty->print_cr("%+45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2210 "(num", seq->num(), seq->sd(), seq->maximum());
2211 }
2212
2213 void TraceGen0TimeData::print() const {
2214 if (!TraceGen0Time) {
2215 return;
2216 }
2217
2218 gclog_or_tty->print_cr("ALL PAUSES");
2219 print_summary_sd(" Total", &_total);
2220 gclog_or_tty->print_cr("");
2221 gclog_or_tty->print_cr("");
2222 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num);
2223 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num);
2224 gclog_or_tty->print_cr("");
2225
2226 gclog_or_tty->print_cr("EVACUATION PAUSES");
2227
2228 if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2229 gclog_or_tty->print_cr("none");
2230 } else {
2231 print_summary_sd(" Evacuation Pauses", &_total);
2232 print_summary(" Root Region Scan Wait", &_root_region_scan_wait);
2233 print_summary(" Parallel Time", &_parallel);
2234 print_summary(" Ext Root Scanning", &_ext_root_scan);
2235 print_summary(" SATB Filtering", &_satb_filtering);
2236 print_summary(" Update RS", &_update_rs);
2237 print_summary(" Scan RS", &_scan_rs);
2238 print_summary(" Object Copy", &_obj_copy);
2239 print_summary(" Termination", &_termination);
2240 print_summary(" Parallel Other", &_parallel_other);
2241 print_summary(" Clear CT", &_clear_ct);
2242 print_summary(" Other", &_other);
2243 }
2244 gclog_or_tty->print_cr("");
2245
2246 gclog_or_tty->print_cr("MISC");
2247 print_summary_sd(" Stop World", &_all_stop_world_times_ms);
2248 print_summary_sd(" Yields", &_all_yield_times_ms);
2249 }
2250
2251 void TraceGen1TimeData::record_full_collection(double full_gc_time_ms) {
2252 if (TraceGen1Time) {
2253 _all_full_gc_times.add(full_gc_time_ms);
2254 }
2255 }
2256
2257 void TraceGen1TimeData::print() const {
2258 if (!TraceGen1Time) {
2259 return;
2260 }
2261
2262 if (_all_full_gc_times.num() > 0) {
2263 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2264 _all_full_gc_times.num(),
2265 _all_full_gc_times.sum() / 1000.0);
2266 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2267 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2268 _all_full_gc_times.sd(),
2269 _all_full_gc_times.maximum());
2270 }
2271 }