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