1 /*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/concurrentG1Refine.hpp"
27 #include "gc/g1/concurrentMark.hpp"
28 #include "gc/g1/concurrentMarkThread.inline.hpp"
29 #include "gc/g1/g1CollectedHeap.inline.hpp"
30 #include "gc/g1/g1CollectorPolicy.hpp"
31 #include "gc/g1/g1ErgoVerbose.hpp"
32 #include "gc/g1/g1GCPhaseTimes.hpp"
33 #include "gc/g1/g1Log.hpp"
34 #include "gc/g1/heapRegion.inline.hpp"
35 #include "gc/g1/heapRegionRemSet.hpp"
36 #include "gc/shared/gcPolicyCounters.hpp"
37 #include "runtime/arguments.hpp"
38 #include "runtime/java.hpp"
39 #include "runtime/mutexLocker.hpp"
40 #include "utilities/debug.hpp"
41
42 // Different defaults for different number of GC threads
43 // They were chosen by running GCOld and SPECjbb on debris with different
44 // numbers of GC threads and choosing them based on the results
45
46 // all the same
47 static double rs_length_diff_defaults[] = {
48 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
49 };
50
51 static double cost_per_card_ms_defaults[] = {
52 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
53 };
54
55 // all the same
56 static double young_cards_per_entry_ratio_defaults[] = {
57 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
58 };
59
60 static double cost_per_entry_ms_defaults[] = {
61 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
62 };
63
64 static double cost_per_byte_ms_defaults[] = {
65 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
66 };
67
68 // these should be pretty consistent
69 static double constant_other_time_ms_defaults[] = {
70 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
71 };
72
73
74 static double young_other_cost_per_region_ms_defaults[] = {
75 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
76 };
77
78 static double non_young_other_cost_per_region_ms_defaults[] = {
79 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
80 };
81
82 G1CollectorPolicy::G1CollectorPolicy() :
83 _predictor(G1ConfidencePercent / 100.0),
84 _parallel_gc_threads(ParallelGCThreads),
85
86 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
87 _stop_world_start(0.0),
88
89 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
90 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
91
92 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
93 _prev_collection_pause_end_ms(0.0),
94 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
95 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
96 _cost_scan_hcc_seq(new TruncatedSeq(TruncatedSeqLength)),
97 _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
98 _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
99 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
100 _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
101 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
102 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
103 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
104 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
105 _non_young_other_cost_per_region_ms_seq(
106 new TruncatedSeq(TruncatedSeqLength)),
107
108 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
109 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
110
111 _pause_time_target_ms((double) MaxGCPauseMillis),
112
113 _recent_prev_end_times_for_all_gcs_sec(
114 new TruncatedSeq(NumPrevPausesForHeuristics)),
115
116 _recent_avg_pause_time_ratio(0.0),
117 _rs_lengths_prediction(0),
118 _max_survivor_regions(0),
119
120 _eden_used_bytes_before_gc(0),
121 _survivor_used_bytes_before_gc(0),
122 _heap_used_bytes_before_gc(0),
123 _metaspace_used_bytes_before_gc(0),
124 _eden_capacity_bytes_before_gc(0),
125 _heap_capacity_bytes_before_gc(0),
126
127 _eden_cset_region_length(0),
128 _survivor_cset_region_length(0),
129 _old_cset_region_length(0),
130
131 _collection_set(NULL),
132 _collection_set_bytes_used_before(0),
133
134 // Incremental CSet attributes
135 _inc_cset_build_state(Inactive),
136 _inc_cset_head(NULL),
137 _inc_cset_tail(NULL),
138 _inc_cset_bytes_used_before(0),
139 _inc_cset_max_finger(NULL),
140 _inc_cset_recorded_rs_lengths(0),
141 _inc_cset_recorded_rs_lengths_diffs(0),
142 _inc_cset_predicted_elapsed_time_ms(0.0),
143 _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
144
145 // add here any more surv rate groups
146 _recorded_survivor_regions(0),
147 _recorded_survivor_head(NULL),
148 _recorded_survivor_tail(NULL),
149 _survivors_age_table(true),
150
151 _gc_overhead_perc(0.0) {
152
153 // SurvRateGroups below must be initialized after the predictor because they
154 // indirectly use it through this object passed to their constructor.
155 _short_lived_surv_rate_group =
156 new SurvRateGroup(&_predictor, "Short Lived", G1YoungSurvRateNumRegionsSummary);
157 _survivor_surv_rate_group =
158 new SurvRateGroup(&_predictor, "Survivor", G1YoungSurvRateNumRegionsSummary);
159
160 // Set up the region size and associated fields. Given that the
161 // policy is created before the heap, we have to set this up here,
162 // so it's done as soon as possible.
163
164 // It would have been natural to pass initial_heap_byte_size() and
165 // max_heap_byte_size() to setup_heap_region_size() but those have
166 // not been set up at this point since they should be aligned with
167 // the region size. So, there is a circular dependency here. We base
168 // the region size on the heap size, but the heap size should be
169 // aligned with the region size. To get around this we use the
170 // unaligned values for the heap.
171 HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
172 HeapRegionRemSet::setup_remset_size();
173
174 G1ErgoVerbose::initialize();
175 if (PrintAdaptiveSizePolicy) {
176 // Currently, we only use a single switch for all the heuristics.
177 G1ErgoVerbose::set_enabled(true);
178 // Given that we don't currently have a verboseness level
179 // parameter, we'll hardcode this to high. This can be easily
180 // changed in the future.
181 G1ErgoVerbose::set_level(ErgoHigh);
182 } else {
183 G1ErgoVerbose::set_enabled(false);
184 }
185
186 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
187 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
188
189 _phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
190
191 int index = MIN2(_parallel_gc_threads - 1, 7);
192
193 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
194 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
195 _cost_scan_hcc_seq->add(0.0);
196 _young_cards_per_entry_ratio_seq->add(
197 young_cards_per_entry_ratio_defaults[index]);
198 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
199 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
200 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
201 _young_other_cost_per_region_ms_seq->add(
202 young_other_cost_per_region_ms_defaults[index]);
203 _non_young_other_cost_per_region_ms_seq->add(
204 non_young_other_cost_per_region_ms_defaults[index]);
205
206 // Below, we might need to calculate the pause time target based on
207 // the pause interval. When we do so we are going to give G1 maximum
208 // flexibility and allow it to do pauses when it needs to. So, we'll
209 // arrange that the pause interval to be pause time target + 1 to
210 // ensure that a) the pause time target is maximized with respect to
211 // the pause interval and b) we maintain the invariant that pause
212 // time target < pause interval. If the user does not want this
213 // maximum flexibility, they will have to set the pause interval
214 // explicitly.
215
216 // First make sure that, if either parameter is set, its value is
217 // reasonable.
218 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
219 if (MaxGCPauseMillis < 1) {
220 vm_exit_during_initialization("MaxGCPauseMillis should be "
221 "greater than 0");
222 }
223 }
224 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
225 if (GCPauseIntervalMillis < 1) {
226 vm_exit_during_initialization("GCPauseIntervalMillis should be "
227 "greater than 0");
228 }
229 }
230
231 // Then, if the pause time target parameter was not set, set it to
232 // the default value.
233 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
234 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
235 // The default pause time target in G1 is 200ms
236 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
237 } else {
238 // We do not allow the pause interval to be set without the
239 // pause time target
240 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
241 "without setting MaxGCPauseMillis");
242 }
243 }
244
245 // Then, if the interval parameter was not set, set it according to
246 // the pause time target (this will also deal with the case when the
247 // pause time target is the default value).
248 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
249 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
250 }
251
252 // Finally, make sure that the two parameters are consistent.
253 if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
254 char buffer[256];
255 jio_snprintf(buffer, 256,
256 "MaxGCPauseMillis (%u) should be less than "
257 "GCPauseIntervalMillis (%u)",
258 MaxGCPauseMillis, GCPauseIntervalMillis);
259 vm_exit_during_initialization(buffer);
260 }
261
262 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
263 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
264 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
265
266 // start conservatively (around 50ms is about right)
267 _concurrent_mark_remark_times_ms->add(0.05);
268 _concurrent_mark_cleanup_times_ms->add(0.20);
269 _tenuring_threshold = MaxTenuringThreshold;
270
271 assert(GCTimeRatio > 0,
272 "we should have set it to a default value set_g1_gc_flags() "
273 "if a user set it to 0");
274 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
275
276 uintx reserve_perc = G1ReservePercent;
277 // Put an artificial ceiling on this so that it's not set to a silly value.
278 if (reserve_perc > 50) {
279 reserve_perc = 50;
280 warning("G1ReservePercent is set to a value that is too large, "
281 "it's been updated to " UINTX_FORMAT, reserve_perc);
282 }
283 _reserve_factor = (double) reserve_perc / 100.0;
284 // This will be set when the heap is expanded
285 // for the first time during initialization.
286 _reserve_regions = 0;
287
288 _collectionSetChooser = new CollectionSetChooser();
289 }
290
291 double G1CollectorPolicy::get_new_prediction(TruncatedSeq const* seq) const {
292 return _predictor.get_new_prediction(seq);
293 }
294
295 void G1CollectorPolicy::initialize_alignments() {
296 _space_alignment = HeapRegion::GrainBytes;
297 size_t card_table_alignment = CardTableRS::ct_max_alignment_constraint();
298 size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
299 _heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
300 }
301
302 void G1CollectorPolicy::initialize_flags() {
303 if (G1HeapRegionSize != HeapRegion::GrainBytes) {
304 FLAG_SET_ERGO(size_t, G1HeapRegionSize, HeapRegion::GrainBytes);
305 }
306
307 if (SurvivorRatio < 1) {
308 vm_exit_during_initialization("Invalid survivor ratio specified");
309 }
310 CollectorPolicy::initialize_flags();
311 _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
312 }
313
314 void G1CollectorPolicy::post_heap_initialize() {
315 uintx max_regions = G1CollectedHeap::heap()->max_regions();
316 size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
317 if (max_young_size != MaxNewSize) {
318 FLAG_SET_ERGO(size_t, MaxNewSize, max_young_size);
319 }
320 }
321
322 G1CollectorState* G1CollectorPolicy::collector_state() const { return _g1->collector_state(); }
323
324 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
325 _min_desired_young_length(0), _max_desired_young_length(0) {
326 if (FLAG_IS_CMDLINE(NewRatio)) {
327 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
328 warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
329 } else {
330 _sizer_kind = SizerNewRatio;
331 _adaptive_size = false;
332 return;
333 }
334 }
335
336 if (NewSize > MaxNewSize) {
337 if (FLAG_IS_CMDLINE(MaxNewSize)) {
338 warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
339 "A new max generation size of " SIZE_FORMAT "k will be used.",
340 NewSize/K, MaxNewSize/K, NewSize/K);
341 }
342 MaxNewSize = NewSize;
343 }
344
345 if (FLAG_IS_CMDLINE(NewSize)) {
346 _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
347 1U);
348 if (FLAG_IS_CMDLINE(MaxNewSize)) {
349 _max_desired_young_length =
350 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
351 1U);
352 _sizer_kind = SizerMaxAndNewSize;
353 _adaptive_size = _min_desired_young_length == _max_desired_young_length;
354 } else {
355 _sizer_kind = SizerNewSizeOnly;
356 }
357 } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
358 _max_desired_young_length =
359 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
360 1U);
361 _sizer_kind = SizerMaxNewSizeOnly;
362 }
363 }
364
365 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
366 uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
367 return MAX2(1U, default_value);
368 }
369
370 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
371 uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
372 return MAX2(1U, default_value);
373 }
374
375 void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
376 assert(number_of_heap_regions > 0, "Heap must be initialized");
377
378 switch (_sizer_kind) {
379 case SizerDefaults:
380 *min_young_length = calculate_default_min_length(number_of_heap_regions);
381 *max_young_length = calculate_default_max_length(number_of_heap_regions);
382 break;
383 case SizerNewSizeOnly:
384 *max_young_length = calculate_default_max_length(number_of_heap_regions);
385 *max_young_length = MAX2(*min_young_length, *max_young_length);
386 break;
387 case SizerMaxNewSizeOnly:
388 *min_young_length = calculate_default_min_length(number_of_heap_regions);
389 *min_young_length = MIN2(*min_young_length, *max_young_length);
390 break;
391 case SizerMaxAndNewSize:
392 // Do nothing. Values set on the command line, don't update them at runtime.
393 break;
394 case SizerNewRatio:
395 *min_young_length = number_of_heap_regions / (NewRatio + 1);
396 *max_young_length = *min_young_length;
397 break;
398 default:
399 ShouldNotReachHere();
400 }
401
402 assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
403 }
404
405 uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
406 // We need to pass the desired values because recalculation may not update these
407 // values in some cases.
408 uint temp = _min_desired_young_length;
409 uint result = _max_desired_young_length;
410 recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
411 return result;
412 }
413
414 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
415 recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
416 &_max_desired_young_length);
417 }
418
419 void G1CollectorPolicy::init() {
420 // Set aside an initial future to_space.
421 _g1 = G1CollectedHeap::heap();
422
423 assert(Heap_lock->owned_by_self(), "Locking discipline.");
424
425 initialize_gc_policy_counters();
426
427 if (adaptive_young_list_length()) {
428 _young_list_fixed_length = 0;
429 } else {
430 _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
431 }
432 _free_regions_at_end_of_collection = _g1->num_free_regions();
433
434 update_young_list_max_and_target_length();
435 // We may immediately start allocating regions and placing them on the
436 // collection set list. Initialize the per-collection set info
437 start_incremental_cset_building();
438 }
439
440 void G1CollectorPolicy::note_gc_start(uint num_active_workers) {
441 phase_times()->note_gc_start(num_active_workers);
442 }
443
444 // Create the jstat counters for the policy.
445 void G1CollectorPolicy::initialize_gc_policy_counters() {
446 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
447 }
448
449 bool G1CollectorPolicy::predict_will_fit(uint young_length,
450 double base_time_ms,
451 uint base_free_regions,
452 double target_pause_time_ms) const {
453 if (young_length >= base_free_regions) {
454 // end condition 1: not enough space for the young regions
455 return false;
456 }
457
458 double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
459 size_t bytes_to_copy =
460 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
461 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
462 double young_other_time_ms = predict_young_other_time_ms(young_length);
463 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
464 if (pause_time_ms > target_pause_time_ms) {
465 // end condition 2: prediction is over the target pause time
466 return false;
467 }
468
469 size_t free_bytes = (base_free_regions - young_length) * HeapRegion::GrainBytes;
470 if ((2.0 /* magic */ * _predictor.sigma()) * bytes_to_copy > free_bytes) {
471 // end condition 3: out-of-space (conservatively!)
472 return false;
473 }
474
475 // success!
476 return true;
477 }
478
479 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
480 // re-calculate the necessary reserve
481 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
482 // We use ceiling so that if reserve_regions_d is > 0.0 (but
483 // smaller than 1.0) we'll get 1.
484 _reserve_regions = (uint) ceil(reserve_regions_d);
485
486 _young_gen_sizer->heap_size_changed(new_number_of_regions);
487 }
488
489 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
490 uint base_min_length) const {
491 uint desired_min_length = 0;
492 if (adaptive_young_list_length()) {
493 if (_alloc_rate_ms_seq->num() > 3) {
494 double now_sec = os::elapsedTime();
495 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
496 double alloc_rate_ms = predict_alloc_rate_ms();
497 desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
498 } else {
499 // otherwise we don't have enough info to make the prediction
500 }
501 }
502 desired_min_length += base_min_length;
503 // make sure we don't go below any user-defined minimum bound
504 return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
505 }
506
507 uint G1CollectorPolicy::calculate_young_list_desired_max_length() const {
508 // Here, we might want to also take into account any additional
509 // constraints (i.e., user-defined minimum bound). Currently, we
510 // effectively don't set this bound.
511 return _young_gen_sizer->max_desired_young_length();
512 }
513
514 void G1CollectorPolicy::update_young_list_max_and_target_length() {
515 update_young_list_max_and_target_length(get_new_prediction(_rs_lengths_seq));
516 }
517
518 void G1CollectorPolicy::update_young_list_max_and_target_length(size_t rs_lengths) {
519 update_young_list_target_length(rs_lengths);
520 update_max_gc_locker_expansion();
521 }
522
523 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
524 _young_list_target_length = bounded_young_list_target_length(rs_lengths);
525 }
526
527 void G1CollectorPolicy::update_young_list_target_length() {
528 update_young_list_target_length(get_new_prediction(_rs_lengths_seq));
529 }
530
531 uint G1CollectorPolicy::bounded_young_list_target_length(size_t rs_lengths) const {
532 // Calculate the absolute and desired min bounds.
533
534 // This is how many young regions we already have (currently: the survivors).
535 uint base_min_length = recorded_survivor_regions();
536 uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
537 // This is the absolute minimum young length. Ensure that we
538 // will at least have one eden region available for allocation.
539 uint absolute_min_length = base_min_length + MAX2(_g1->young_list()->eden_length(), (uint)1);
540 // If we shrank the young list target it should not shrink below the current size.
541 desired_min_length = MAX2(desired_min_length, absolute_min_length);
542 // Calculate the absolute and desired max bounds.
543
544 // We will try our best not to "eat" into the reserve.
545 uint absolute_max_length = 0;
546 if (_free_regions_at_end_of_collection > _reserve_regions) {
547 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
548 }
549 uint desired_max_length = calculate_young_list_desired_max_length();
550 if (desired_max_length > absolute_max_length) {
551 desired_max_length = absolute_max_length;
552 }
553
554 uint young_list_target_length = 0;
555 if (adaptive_young_list_length()) {
556 if (collector_state()->gcs_are_young()) {
557 young_list_target_length =
558 calculate_young_list_target_length(rs_lengths,
559 base_min_length,
560 desired_min_length,
561 desired_max_length);
562 } else {
563 // Don't calculate anything and let the code below bound it to
564 // the desired_min_length, i.e., do the next GC as soon as
565 // possible to maximize how many old regions we can add to it.
566 }
567 } else {
568 // The user asked for a fixed young gen so we'll fix the young gen
569 // whether the next GC is young or mixed.
570 young_list_target_length = _young_list_fixed_length;
571 }
572
573 // Make sure we don't go over the desired max length, nor under the
574 // desired min length. In case they clash, desired_min_length wins
575 // which is why that test is second.
576 if (young_list_target_length > desired_max_length) {
577 young_list_target_length = desired_max_length;
578 }
579 if (young_list_target_length < desired_min_length) {
580 young_list_target_length = desired_min_length;
581 }
582
583 assert(young_list_target_length > recorded_survivor_regions(),
584 "we should be able to allocate at least one eden region");
585 assert(young_list_target_length >= absolute_min_length, "post-condition");
586
587 return young_list_target_length;
588 }
589
590 uint
591 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
592 uint base_min_length,
593 uint desired_min_length,
594 uint desired_max_length) const {
595 assert(adaptive_young_list_length(), "pre-condition");
596 assert(collector_state()->gcs_are_young(), "only call this for young GCs");
597
598 // In case some edge-condition makes the desired max length too small...
599 if (desired_max_length <= desired_min_length) {
600 return desired_min_length;
601 }
602
603 // We'll adjust min_young_length and max_young_length not to include
604 // the already allocated young regions (i.e., so they reflect the
605 // min and max eden regions we'll allocate). The base_min_length
606 // will be reflected in the predictions by the
607 // survivor_regions_evac_time prediction.
608 assert(desired_min_length > base_min_length, "invariant");
609 uint min_young_length = desired_min_length - base_min_length;
610 assert(desired_max_length > base_min_length, "invariant");
611 uint max_young_length = desired_max_length - base_min_length;
612
613 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
614 double survivor_regions_evac_time = predict_survivor_regions_evac_time();
615 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
616 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
617 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
618 double base_time_ms =
619 predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
620 survivor_regions_evac_time;
621 uint available_free_regions = _free_regions_at_end_of_collection;
622 uint base_free_regions = 0;
623 if (available_free_regions > _reserve_regions) {
624 base_free_regions = available_free_regions - _reserve_regions;
625 }
626
627 // Here, we will make sure that the shortest young length that
628 // makes sense fits within the target pause time.
629
630 if (predict_will_fit(min_young_length, base_time_ms,
631 base_free_regions, target_pause_time_ms)) {
632 // The shortest young length will fit into the target pause time;
633 // we'll now check whether the absolute maximum number of young
634 // regions will fit in the target pause time. If not, we'll do
635 // a binary search between min_young_length and max_young_length.
636 if (predict_will_fit(max_young_length, base_time_ms,
637 base_free_regions, target_pause_time_ms)) {
638 // The maximum young length will fit into the target pause time.
639 // We are done so set min young length to the maximum length (as
640 // the result is assumed to be returned in min_young_length).
641 min_young_length = max_young_length;
642 } else {
643 // The maximum possible number of young regions will not fit within
644 // the target pause time so we'll search for the optimal
645 // length. The loop invariants are:
646 //
647 // min_young_length < max_young_length
648 // min_young_length is known to fit into the target pause time
649 // max_young_length is known not to fit into the target pause time
650 //
651 // Going into the loop we know the above hold as we've just
652 // checked them. Every time around the loop we check whether
653 // the middle value between min_young_length and
654 // max_young_length fits into the target pause time. If it
655 // does, it becomes the new min. If it doesn't, it becomes
656 // the new max. This way we maintain the loop invariants.
657
658 assert(min_young_length < max_young_length, "invariant");
659 uint diff = (max_young_length - min_young_length) / 2;
660 while (diff > 0) {
661 uint young_length = min_young_length + diff;
662 if (predict_will_fit(young_length, base_time_ms,
663 base_free_regions, target_pause_time_ms)) {
664 min_young_length = young_length;
665 } else {
666 max_young_length = young_length;
667 }
668 assert(min_young_length < max_young_length, "invariant");
669 diff = (max_young_length - min_young_length) / 2;
670 }
671 // The results is min_young_length which, according to the
672 // loop invariants, should fit within the target pause time.
673
674 // These are the post-conditions of the binary search above:
675 assert(min_young_length < max_young_length,
676 "otherwise we should have discovered that max_young_length "
677 "fits into the pause target and not done the binary search");
678 assert(predict_will_fit(min_young_length, base_time_ms,
679 base_free_regions, target_pause_time_ms),
680 "min_young_length, the result of the binary search, should "
681 "fit into the pause target");
682 assert(!predict_will_fit(min_young_length + 1, base_time_ms,
683 base_free_regions, target_pause_time_ms),
684 "min_young_length, the result of the binary search, should be "
685 "optimal, so no larger length should fit into the pause target");
686 }
687 } else {
688 // Even the minimum length doesn't fit into the pause time
689 // target, return it as the result nevertheless.
690 }
691 return base_min_length + min_young_length;
692 }
693
694 double G1CollectorPolicy::predict_survivor_regions_evac_time() const {
695 double survivor_regions_evac_time = 0.0;
696 for (HeapRegion * r = _recorded_survivor_head;
697 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
698 r = r->get_next_young_region()) {
699 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, collector_state()->gcs_are_young());
700 }
701 return survivor_regions_evac_time;
702 }
703
704 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
705 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
706
707 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
708 if (rs_lengths > _rs_lengths_prediction) {
709 // add 10% to avoid having to recalculate often
710 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
711 update_rs_lengths_prediction(rs_lengths_prediction);
712
713 update_young_list_max_and_target_length(rs_lengths_prediction);
714 }
715 }
716
717 void G1CollectorPolicy::update_rs_lengths_prediction() {
718 update_rs_lengths_prediction(get_new_prediction(_rs_lengths_seq));
719 }
720
721 void G1CollectorPolicy::update_rs_lengths_prediction(size_t prediction) {
722 if (collector_state()->gcs_are_young() && adaptive_young_list_length()) {
723 _rs_lengths_prediction = prediction;
724 }
725 }
726
727 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
728 bool is_tlab,
729 bool* gc_overhead_limit_was_exceeded) {
730 guarantee(false, "Not using this policy feature yet.");
731 return NULL;
732 }
733
734 // This method controls how a collector handles one or more
735 // of its generations being fully allocated.
736 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
737 bool is_tlab) {
738 guarantee(false, "Not using this policy feature yet.");
739 return NULL;
740 }
741
742
743 #ifndef PRODUCT
744 bool G1CollectorPolicy::verify_young_ages() {
745 HeapRegion* head = _g1->young_list()->first_region();
746 return
747 verify_young_ages(head, _short_lived_surv_rate_group);
748 // also call verify_young_ages on any additional surv rate groups
749 }
750
751 bool
752 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
753 SurvRateGroup *surv_rate_group) {
754 guarantee( surv_rate_group != NULL, "pre-condition" );
755
756 const char* name = surv_rate_group->name();
757 bool ret = true;
758 int prev_age = -1;
759
760 for (HeapRegion* curr = head;
761 curr != NULL;
762 curr = curr->get_next_young_region()) {
763 SurvRateGroup* group = curr->surv_rate_group();
764 if (group == NULL && !curr->is_survivor()) {
765 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
766 ret = false;
767 }
768
769 if (surv_rate_group == group) {
770 int age = curr->age_in_surv_rate_group();
771
772 if (age < 0) {
773 gclog_or_tty->print_cr("## %s: encountered negative age", name);
774 ret = false;
775 }
776
777 if (age <= prev_age) {
778 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
779 "(%d, %d)", name, age, prev_age);
780 ret = false;
781 }
782 prev_age = age;
783 }
784 }
785
786 return ret;
787 }
788 #endif // PRODUCT
789
790 void G1CollectorPolicy::record_full_collection_start() {
791 _full_collection_start_sec = os::elapsedTime();
792 record_heap_size_info_at_start(true /* full */);
793 // Release the future to-space so that it is available for compaction into.
794 collector_state()->set_full_collection(true);
795 }
796
797 void G1CollectorPolicy::record_full_collection_end() {
798 // Consider this like a collection pause for the purposes of allocation
799 // since last pause.
800 double end_sec = os::elapsedTime();
801 double full_gc_time_sec = end_sec - _full_collection_start_sec;
802 double full_gc_time_ms = full_gc_time_sec * 1000.0;
803
804 _trace_old_gen_time_data.record_full_collection(full_gc_time_ms);
805
806 update_recent_gc_times(end_sec, full_gc_time_ms);
807
808 collector_state()->set_full_collection(false);
809
810 // "Nuke" the heuristics that control the young/mixed GC
811 // transitions and make sure we start with young GCs after the Full GC.
812 collector_state()->set_gcs_are_young(true);
813 collector_state()->set_last_young_gc(false);
814 collector_state()->set_initiate_conc_mark_if_possible(false);
815 collector_state()->set_during_initial_mark_pause(false);
816 collector_state()->set_in_marking_window(false);
817 collector_state()->set_in_marking_window_im(false);
818
819 _short_lived_surv_rate_group->start_adding_regions();
820 // also call this on any additional surv rate groups
821
822 record_survivor_regions(0, NULL, NULL);
823
824 _free_regions_at_end_of_collection = _g1->num_free_regions();
825 // Reset survivors SurvRateGroup.
826 _survivor_surv_rate_group->reset();
827 update_young_list_max_and_target_length();
828 update_rs_lengths_prediction();
829 _collectionSetChooser->clear();
830 }
831
832 void G1CollectorPolicy::record_stop_world_start() {
833 _stop_world_start = os::elapsedTime();
834 }
835
836 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec) {
837 // We only need to do this here as the policy will only be applied
838 // to the GC we're about to start. so, no point is calculating this
839 // every time we calculate / recalculate the target young length.
840 update_survivors_policy();
841
842 assert(_g1->used() == _g1->recalculate_used(),
843 "sanity, used: " SIZE_FORMAT " recalculate_used: " SIZE_FORMAT,
844 _g1->used(), _g1->recalculate_used());
845
846 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
847 _trace_young_gen_time_data.record_start_collection(s_w_t_ms);
848 _stop_world_start = 0.0;
849
850 record_heap_size_info_at_start(false /* full */);
851
852 phase_times()->record_cur_collection_start_sec(start_time_sec);
853 _pending_cards = _g1->pending_card_num();
854
855 _collection_set_bytes_used_before = 0;
856 _bytes_copied_during_gc = 0;
857
858 collector_state()->set_last_gc_was_young(false);
859
860 // do that for any other surv rate groups
861 _short_lived_surv_rate_group->stop_adding_regions();
862 _survivors_age_table.clear();
863
864 assert( verify_young_ages(), "region age verification" );
865 }
866
867 void G1CollectorPolicy::record_concurrent_mark_init_end(double
868 mark_init_elapsed_time_ms) {
869 collector_state()->set_during_marking(true);
870 assert(!collector_state()->initiate_conc_mark_if_possible(), "we should have cleared it by now");
871 collector_state()->set_during_initial_mark_pause(false);
872 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
873 }
874
875 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
876 _mark_remark_start_sec = os::elapsedTime();
877 collector_state()->set_during_marking(false);
878 }
879
880 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
881 double end_time_sec = os::elapsedTime();
882 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
883 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
884 _cur_mark_stop_world_time_ms += elapsed_time_ms;
885 _prev_collection_pause_end_ms += elapsed_time_ms;
886
887 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec);
888 }
889
890 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
891 _mark_cleanup_start_sec = os::elapsedTime();
892 }
893
894 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
895 collector_state()->set_last_young_gc(true);
896 collector_state()->set_in_marking_window(false);
897 }
898
899 void G1CollectorPolicy::record_concurrent_pause() {
900 if (_stop_world_start > 0.0) {
901 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
902 _trace_young_gen_time_data.record_yield_time(yield_ms);
903 }
904 }
905
906 double G1CollectorPolicy::average_time_ms(G1GCPhaseTimes::GCParPhases phase) const {
907 return phase_times()->average_time_ms(phase);
908 }
909
910 double G1CollectorPolicy::young_other_time_ms() const {
911 return phase_times()->young_cset_choice_time_ms() +
912 phase_times()->young_free_cset_time_ms();
913 }
914
915 double G1CollectorPolicy::non_young_other_time_ms() const {
916 return phase_times()->non_young_cset_choice_time_ms() +
917 phase_times()->non_young_free_cset_time_ms();
918
919 }
920
921 double G1CollectorPolicy::other_time_ms(double pause_time_ms) const {
922 return pause_time_ms -
923 average_time_ms(G1GCPhaseTimes::UpdateRS) -
924 average_time_ms(G1GCPhaseTimes::ScanRS) -
925 average_time_ms(G1GCPhaseTimes::ObjCopy) -
926 average_time_ms(G1GCPhaseTimes::Termination);
927 }
928
929 double G1CollectorPolicy::constant_other_time_ms(double pause_time_ms) const {
930 return other_time_ms(pause_time_ms) - young_other_time_ms() - non_young_other_time_ms();
931 }
932
933 bool G1CollectorPolicy::about_to_start_mixed_phase() const {
934 return _g1->concurrent_mark()->cmThread()->during_cycle() || collector_state()->last_young_gc();
935 }
936
937 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
938 if (about_to_start_mixed_phase()) {
939 return false;
940 }
941
942 size_t marking_initiating_used_threshold =
943 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
944 size_t cur_used_bytes = _g1->non_young_capacity_bytes();
945 size_t alloc_byte_size = alloc_word_size * HeapWordSize;
946
947 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
948 if (collector_state()->gcs_are_young() && !collector_state()->last_young_gc()) {
949 ergo_verbose5(ErgoConcCycles,
950 "request concurrent cycle initiation",
951 ergo_format_reason("occupancy higher than threshold")
952 ergo_format_byte("occupancy")
953 ergo_format_byte("allocation request")
954 ergo_format_byte_perc("threshold")
955 ergo_format_str("source"),
956 cur_used_bytes,
957 alloc_byte_size,
958 marking_initiating_used_threshold,
959 (double) InitiatingHeapOccupancyPercent,
960 source);
961 return true;
962 } else {
963 ergo_verbose5(ErgoConcCycles,
964 "do not request concurrent cycle initiation",
965 ergo_format_reason("still doing mixed collections")
966 ergo_format_byte("occupancy")
967 ergo_format_byte("allocation request")
968 ergo_format_byte_perc("threshold")
969 ergo_format_str("source"),
970 cur_used_bytes,
971 alloc_byte_size,
972 marking_initiating_used_threshold,
973 (double) InitiatingHeapOccupancyPercent,
974 source);
975 }
976 }
977
978 return false;
979 }
980
981 // Anything below that is considered to be zero
982 #define MIN_TIMER_GRANULARITY 0.0000001
983
984 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, size_t cards_scanned) {
985 double end_time_sec = os::elapsedTime();
986 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
987 "otherwise, the subtraction below does not make sense");
988 size_t rs_size =
989 _cur_collection_pause_used_regions_at_start - cset_region_length();
990 size_t cur_used_bytes = _g1->used();
991 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
992 bool last_pause_included_initial_mark = false;
993 bool update_stats = !_g1->evacuation_failed();
994
995 #ifndef PRODUCT
996 if (G1YoungSurvRateVerbose) {
997 gclog_or_tty->cr();
998 _short_lived_surv_rate_group->print();
999 // do that for any other surv rate groups too
1000 }
1001 #endif // PRODUCT
1002
1003 last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
1004 if (last_pause_included_initial_mark) {
1005 record_concurrent_mark_init_end(0.0);
1006 } else if (need_to_start_conc_mark("end of GC")) {
1007 // Note: this might have already been set, if during the last
1008 // pause we decided to start a cycle but at the beginning of
1009 // this pause we decided to postpone it. That's OK.
1010 collector_state()->set_initiate_conc_mark_if_possible(true);
1011 }
1012
1013 _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0, end_time_sec);
1014
1015 if (update_stats) {
1016 _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times());
1017 // this is where we update the allocation rate of the application
1018 double app_time_ms =
1019 (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
1020 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1021 // This usually happens due to the timer not having the required
1022 // granularity. Some Linuxes are the usual culprits.
1023 // We'll just set it to something (arbitrarily) small.
1024 app_time_ms = 1.0;
1025 }
1026 // We maintain the invariant that all objects allocated by mutator
1027 // threads will be allocated out of eden regions. So, we can use
1028 // the eden region number allocated since the previous GC to
1029 // calculate the application's allocate rate. The only exception
1030 // to that is humongous objects that are allocated separately. But
1031 // given that humongous object allocations do not really affect
1032 // either the pause's duration nor when the next pause will take
1033 // place we can safely ignore them here.
1034 uint regions_allocated = eden_cset_region_length();
1035 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1036 _alloc_rate_ms_seq->add(alloc_rate_ms);
1037
1038 double interval_ms =
1039 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1040 update_recent_gc_times(end_time_sec, pause_time_ms);
1041 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1042 if (recent_avg_pause_time_ratio() < 0.0 ||
1043 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1044 #ifndef PRODUCT
1045 // Dump info to allow post-facto debugging
1046 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1047 gclog_or_tty->print_cr("-------------------------------------------");
1048 gclog_or_tty->print_cr("Recent GC Times (ms):");
1049 _recent_gc_times_ms->dump();
1050 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1051 _recent_prev_end_times_for_all_gcs_sec->dump();
1052 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1053 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1054 // In debug mode, terminate the JVM if the user wants to debug at this point.
1055 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1056 #endif // !PRODUCT
1057 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1058 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1059 if (_recent_avg_pause_time_ratio < 0.0) {
1060 _recent_avg_pause_time_ratio = 0.0;
1061 } else {
1062 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1063 _recent_avg_pause_time_ratio = 1.0;
1064 }
1065 }
1066 }
1067
1068 bool new_in_marking_window = collector_state()->in_marking_window();
1069 bool new_in_marking_window_im = false;
1070 if (last_pause_included_initial_mark) {
1071 new_in_marking_window = true;
1072 new_in_marking_window_im = true;
1073 }
1074
1075 if (collector_state()->last_young_gc()) {
1076 // This is supposed to to be the "last young GC" before we start
1077 // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1078 assert(!last_pause_included_initial_mark, "The last young GC is not allowed to be an initial mark GC");
1079
1080 if (next_gc_should_be_mixed("start mixed GCs",
1081 "do not start mixed GCs")) {
1082 collector_state()->set_gcs_are_young(false);
1083 }
1084
1085 collector_state()->set_last_young_gc(false);
1086 }
1087
1088 if (!collector_state()->last_gc_was_young()) {
1089 // This is a mixed GC. Here we decide whether to continue doing
1090 // mixed GCs or not.
1091
1092 if (!next_gc_should_be_mixed("continue mixed GCs",
1093 "do not continue mixed GCs")) {
1094 collector_state()->set_gcs_are_young(true);
1095 }
1096 }
1097
1098 _short_lived_surv_rate_group->start_adding_regions();
1099 // Do that for any other surv rate groups
1100
1101 if (update_stats) {
1102 double cost_per_card_ms = 0.0;
1103 double cost_scan_hcc = average_time_ms(G1GCPhaseTimes::ScanHCC);
1104 if (_pending_cards > 0) {
1105 cost_per_card_ms = (average_time_ms(G1GCPhaseTimes::UpdateRS) - cost_scan_hcc) / (double) _pending_cards;
1106 _cost_per_card_ms_seq->add(cost_per_card_ms);
1107 }
1108 _cost_scan_hcc_seq->add(cost_scan_hcc);
1109
1110 double cost_per_entry_ms = 0.0;
1111 if (cards_scanned > 10) {
1112 cost_per_entry_ms = average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
1113 if (collector_state()->last_gc_was_young()) {
1114 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1115 } else {
1116 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1117 }
1118 }
1119
1120 if (_max_rs_lengths > 0) {
1121 double cards_per_entry_ratio =
1122 (double) cards_scanned / (double) _max_rs_lengths;
1123 if (collector_state()->last_gc_was_young()) {
1124 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1125 } else {
1126 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1127 }
1128 }
1129
1130 // This is defensive. For a while _max_rs_lengths could get
1131 // smaller than _recorded_rs_lengths which was causing
1132 // rs_length_diff to get very large and mess up the RSet length
1133 // predictions. The reason was unsafe concurrent updates to the
1134 // _inc_cset_recorded_rs_lengths field which the code below guards
1135 // against (see CR 7118202). This bug has now been fixed (see CR
1136 // 7119027). However, I'm still worried that
1137 // _inc_cset_recorded_rs_lengths might still end up somewhat
1138 // inaccurate. The concurrent refinement thread calculates an
1139 // RSet's length concurrently with other CR threads updating it
1140 // which might cause it to calculate the length incorrectly (if,
1141 // say, it's in mid-coarsening). So I'll leave in the defensive
1142 // conditional below just in case.
1143 size_t rs_length_diff = 0;
1144 if (_max_rs_lengths > _recorded_rs_lengths) {
1145 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1146 }
1147 _rs_length_diff_seq->add((double) rs_length_diff);
1148
1149 size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1150 size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1151 double cost_per_byte_ms = 0.0;
1152
1153 if (copied_bytes > 0) {
1154 cost_per_byte_ms = average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
1155 if (collector_state()->in_marking_window()) {
1156 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1157 } else {
1158 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1159 }
1160 }
1161
1162 if (young_cset_region_length() > 0) {
1163 _young_other_cost_per_region_ms_seq->add(young_other_time_ms() /
1164 young_cset_region_length());
1165 }
1166
1167 if (old_cset_region_length() > 0) {
1168 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms() /
1169 old_cset_region_length());
1170 }
1171
1172 _constant_other_time_ms_seq->add(constant_other_time_ms(pause_time_ms));
1173
1174 _pending_cards_seq->add((double) _pending_cards);
1175 _rs_lengths_seq->add((double) _max_rs_lengths);
1176 }
1177
1178 collector_state()->set_in_marking_window(new_in_marking_window);
1179 collector_state()->set_in_marking_window_im(new_in_marking_window_im);
1180 _free_regions_at_end_of_collection = _g1->num_free_regions();
1181 update_young_list_max_and_target_length();
1182 update_rs_lengths_prediction();
1183
1184 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1185 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1186
1187 double scan_hcc_time_ms = average_time_ms(G1GCPhaseTimes::ScanHCC);
1188
1189 if (update_rs_time_goal_ms < scan_hcc_time_ms) {
1190 ergo_verbose2(ErgoTiming,
1191 "adjust concurrent refinement thresholds",
1192 ergo_format_reason("Scanning the HCC expected to take longer than Update RS time goal")
1193 ergo_format_ms("Update RS time goal")
1194 ergo_format_ms("Scan HCC time"),
1195 update_rs_time_goal_ms,
1196 scan_hcc_time_ms);
1197
1198 update_rs_time_goal_ms = 0;
1199 } else {
1200 update_rs_time_goal_ms -= scan_hcc_time_ms;
1201 }
1202 adjust_concurrent_refinement(average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms,
1203 phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS),
1204 update_rs_time_goal_ms);
1205
1206 _collectionSetChooser->verify();
1207 }
1208
1209 #define EXT_SIZE_FORMAT "%.1f%s"
1210 #define EXT_SIZE_PARAMS(bytes) \
1211 byte_size_in_proper_unit((double)(bytes)), \
1212 proper_unit_for_byte_size((bytes))
1213
1214 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1215 YoungList* young_list = _g1->young_list();
1216 _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1217 _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1218 _heap_capacity_bytes_before_gc = _g1->capacity();
1219 _heap_used_bytes_before_gc = _g1->used();
1220 _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1221
1222 _eden_capacity_bytes_before_gc =
1223 (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1224
1225 if (full) {
1226 _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1227 }
1228 }
1229
1230 void G1CollectorPolicy::print_heap_transition(size_t bytes_before) const {
1231 size_t bytes_after = _g1->used();
1232 size_t capacity = _g1->capacity();
1233
1234 gclog_or_tty->print(" " SIZE_FORMAT "%s->" SIZE_FORMAT "%s(" SIZE_FORMAT "%s)",
1235 byte_size_in_proper_unit(bytes_before),
1236 proper_unit_for_byte_size(bytes_before),
1237 byte_size_in_proper_unit(bytes_after),
1238 proper_unit_for_byte_size(bytes_after),
1239 byte_size_in_proper_unit(capacity),
1240 proper_unit_for_byte_size(capacity));
1241 }
1242
1243 void G1CollectorPolicy::print_heap_transition() const {
1244 print_heap_transition(_heap_used_bytes_before_gc);
1245 }
1246
1247 void G1CollectorPolicy::print_detailed_heap_transition(bool full) const {
1248 YoungList* young_list = _g1->young_list();
1249
1250 size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1251 size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1252 size_t heap_used_bytes_after_gc = _g1->used();
1253
1254 size_t heap_capacity_bytes_after_gc = _g1->capacity();
1255 size_t eden_capacity_bytes_after_gc =
1256 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1257
1258 gclog_or_tty->print(
1259 " [Eden: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->" EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ") "
1260 "Survivors: " EXT_SIZE_FORMAT "->" EXT_SIZE_FORMAT " "
1261 "Heap: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->"
1262 EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")]",
1263 EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1264 EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1265 EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1266 EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1267 EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1268 EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1269 EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1270 EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1271 EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1272 EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1273
1274 if (full) {
1275 MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1276 }
1277
1278 gclog_or_tty->cr();
1279 }
1280
1281 void G1CollectorPolicy::print_phases(double pause_time_sec) {
1282 phase_times()->print(pause_time_sec);
1283 }
1284
1285 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1286 double update_rs_processed_buffers,
1287 double goal_ms) {
1288 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1289 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1290
1291 if (G1UseAdaptiveConcRefinement) {
1292 const int k_gy = 3, k_gr = 6;
1293 const double inc_k = 1.1, dec_k = 0.9;
1294
1295 int g = cg1r->green_zone();
1296 if (update_rs_time > goal_ms) {
1297 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1298 } else {
1299 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1300 g = (int)MAX2(g * inc_k, g + 1.0);
1301 }
1302 }
1303 // Change the refinement threads params
1304 cg1r->set_green_zone(g);
1305 cg1r->set_yellow_zone(g * k_gy);
1306 cg1r->set_red_zone(g * k_gr);
1307 cg1r->reinitialize_threads();
1308
1309 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * _predictor.sigma()), 1);
1310 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1311 cg1r->yellow_zone());
1312 // Change the barrier params
1313 dcqs.set_process_completed_threshold(processing_threshold);
1314 dcqs.set_max_completed_queue(cg1r->red_zone());
1315 }
1316
1317 int curr_queue_size = dcqs.completed_buffers_num();
1318 if (curr_queue_size >= cg1r->yellow_zone()) {
1319 dcqs.set_completed_queue_padding(curr_queue_size);
1320 } else {
1321 dcqs.set_completed_queue_padding(0);
1322 }
1323 dcqs.notify_if_necessary();
1324 }
1325
1326 size_t G1CollectorPolicy::predict_rs_length_diff() const {
1327 return (size_t) get_new_prediction(_rs_length_diff_seq);
1328 }
1329
1330 double G1CollectorPolicy::predict_alloc_rate_ms() const {
1331 return get_new_prediction(_alloc_rate_ms_seq);
1332 }
1333
1334 double G1CollectorPolicy::predict_cost_per_card_ms() const {
1335 return get_new_prediction(_cost_per_card_ms_seq);
1336 }
1337
1338 double G1CollectorPolicy::predict_scan_hcc_ms() const {
1339 return get_new_prediction(_cost_scan_hcc_seq);
1340 }
1341
1342 double G1CollectorPolicy::predict_rs_update_time_ms(size_t pending_cards) const {
1343 return pending_cards * predict_cost_per_card_ms() + predict_scan_hcc_ms();
1344 }
1345
1346 double G1CollectorPolicy::predict_young_cards_per_entry_ratio() const {
1347 return get_new_prediction(_young_cards_per_entry_ratio_seq);
1348 }
1349
1350 double G1CollectorPolicy::predict_mixed_cards_per_entry_ratio() const {
1351 if (_mixed_cards_per_entry_ratio_seq->num() < 2) {
1352 return predict_young_cards_per_entry_ratio();
1353 } else {
1354 return get_new_prediction(_mixed_cards_per_entry_ratio_seq);
1355 }
1356 }
1357
1358 size_t G1CollectorPolicy::predict_young_card_num(size_t rs_length) const {
1359 return (size_t) (rs_length * predict_young_cards_per_entry_ratio());
1360 }
1361
1362 size_t G1CollectorPolicy::predict_non_young_card_num(size_t rs_length) const {
1363 return (size_t)(rs_length * predict_mixed_cards_per_entry_ratio());
1364 }
1365
1366 double G1CollectorPolicy::predict_rs_scan_time_ms(size_t card_num) const {
1367 if (collector_state()->gcs_are_young()) {
1368 return card_num * get_new_prediction(_cost_per_entry_ms_seq);
1369 } else {
1370 return predict_mixed_rs_scan_time_ms(card_num);
1371 }
1372 }
1373
1374 double G1CollectorPolicy::predict_mixed_rs_scan_time_ms(size_t card_num) const {
1375 if (_mixed_cost_per_entry_ms_seq->num() < 3) {
1376 return card_num * get_new_prediction(_cost_per_entry_ms_seq);
1377 } else {
1378 return card_num * get_new_prediction(_mixed_cost_per_entry_ms_seq);
1379 }
1380 }
1381
1382 double G1CollectorPolicy::predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const {
1383 if (_cost_per_byte_ms_during_cm_seq->num() < 3) {
1384 return (1.1 * bytes_to_copy) * get_new_prediction(_cost_per_byte_ms_seq);
1385 } else {
1386 return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_during_cm_seq);
1387 }
1388 }
1389
1390 double G1CollectorPolicy::predict_object_copy_time_ms(size_t bytes_to_copy) const {
1391 if (collector_state()->during_concurrent_mark()) {
1392 return predict_object_copy_time_ms_during_cm(bytes_to_copy);
1393 } else {
1394 return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_seq);
1395 }
1396 }
1397
1398 double G1CollectorPolicy::predict_constant_other_time_ms() const {
1399 return get_new_prediction(_constant_other_time_ms_seq);
1400 }
1401
1402 double G1CollectorPolicy::predict_young_other_time_ms(size_t young_num) const {
1403 return young_num * get_new_prediction(_young_other_cost_per_region_ms_seq);
1404 }
1405
1406 double G1CollectorPolicy::predict_non_young_other_time_ms(size_t non_young_num) const {
1407 return non_young_num * get_new_prediction(_non_young_other_cost_per_region_ms_seq);
1408 }
1409
1410 double G1CollectorPolicy::predict_remark_time_ms() const {
1411 return get_new_prediction(_concurrent_mark_remark_times_ms);
1412 }
1413
1414 double G1CollectorPolicy::predict_cleanup_time_ms() const {
1415 return get_new_prediction(_concurrent_mark_cleanup_times_ms);
1416 }
1417
1418 double G1CollectorPolicy::predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const {
1419 TruncatedSeq* seq = surv_rate_group->get_seq(age);
1420 guarantee(seq->num() > 0, "There should be some young gen survivor samples available. Tried to access with age %d", age);
1421 double pred = get_new_prediction(seq);
1422 if (pred > 1.0) {
1423 pred = 1.0;
1424 }
1425 return pred;
1426 }
1427
1428 double G1CollectorPolicy::predict_yg_surv_rate(int age) const {
1429 return predict_yg_surv_rate(age, _short_lived_surv_rate_group);
1430 }
1431
1432 double G1CollectorPolicy::accum_yg_surv_rate_pred(int age) const {
1433 return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
1434 }
1435
1436 double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1437 size_t scanned_cards) const {
1438 return
1439 predict_rs_update_time_ms(pending_cards) +
1440 predict_rs_scan_time_ms(scanned_cards) +
1441 predict_constant_other_time_ms();
1442 }
1443
1444 double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) const {
1445 size_t rs_length = predict_rs_length_diff();
1446 size_t card_num;
1447 if (collector_state()->gcs_are_young()) {
1448 card_num = predict_young_card_num(rs_length);
1449 } else {
1450 card_num = predict_non_young_card_num(rs_length);
1451 }
1452 return predict_base_elapsed_time_ms(pending_cards, card_num);
1453 }
1454
1455 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) const {
1456 size_t bytes_to_copy;
1457 if (hr->is_marked())
1458 bytes_to_copy = hr->max_live_bytes();
1459 else {
1460 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1461 int age = hr->age_in_surv_rate_group();
1462 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1463 bytes_to_copy = (size_t) (hr->used() * yg_surv_rate);
1464 }
1465 return bytes_to_copy;
1466 }
1467
1468 double G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1469 bool for_young_gc) const {
1470 size_t rs_length = hr->rem_set()->occupied();
1471 size_t card_num;
1472
1473 // Predicting the number of cards is based on which type of GC
1474 // we're predicting for.
1475 if (for_young_gc) {
1476 card_num = predict_young_card_num(rs_length);
1477 } else {
1478 card_num = predict_non_young_card_num(rs_length);
1479 }
1480 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1481
1482 double region_elapsed_time_ms =
1483 predict_rs_scan_time_ms(card_num) +
1484 predict_object_copy_time_ms(bytes_to_copy);
1485
1486 // The prediction of the "other" time for this region is based
1487 // upon the region type and NOT the GC type.
1488 if (hr->is_young()) {
1489 region_elapsed_time_ms += predict_young_other_time_ms(1);
1490 } else {
1491 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1492 }
1493 return region_elapsed_time_ms;
1494 }
1495
1496 void G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1497 uint survivor_cset_region_length) {
1498 _eden_cset_region_length = eden_cset_region_length;
1499 _survivor_cset_region_length = survivor_cset_region_length;
1500 _old_cset_region_length = 0;
1501 }
1502
1503 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1504 _recorded_rs_lengths = rs_lengths;
1505 }
1506
1507 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1508 double elapsed_ms) {
1509 _recent_gc_times_ms->add(elapsed_ms);
1510 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1511 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1512 }
1513
1514 size_t G1CollectorPolicy::expansion_amount() const {
1515 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1516 double threshold = _gc_overhead_perc;
1517 if (recent_gc_overhead > threshold) {
1518 // We will double the existing space, or take
1519 // G1ExpandByPercentOfAvailable % of the available expansion
1520 // space, whichever is smaller, bounded below by a minimum
1521 // expansion (unless that's all that's left.)
1522 const size_t min_expand_bytes = 1*M;
1523 size_t reserved_bytes = _g1->max_capacity();
1524 size_t committed_bytes = _g1->capacity();
1525 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1526 size_t expand_bytes;
1527 size_t expand_bytes_via_pct =
1528 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1529 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1530 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1531 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1532
1533 ergo_verbose5(ErgoHeapSizing,
1534 "attempt heap expansion",
1535 ergo_format_reason("recent GC overhead higher than "
1536 "threshold after GC")
1537 ergo_format_perc("recent GC overhead")
1538 ergo_format_perc("threshold")
1539 ergo_format_byte("uncommitted")
1540 ergo_format_byte_perc("calculated expansion amount"),
1541 recent_gc_overhead, threshold,
1542 uncommitted_bytes,
1543 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1544
1545 return expand_bytes;
1546 } else {
1547 return 0;
1548 }
1549 }
1550
1551 void G1CollectorPolicy::print_tracing_info() const {
1552 _trace_young_gen_time_data.print();
1553 _trace_old_gen_time_data.print();
1554 }
1555
1556 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1557 #ifndef PRODUCT
1558 _short_lived_surv_rate_group->print_surv_rate_summary();
1559 // add this call for any other surv rate groups
1560 #endif // PRODUCT
1561 }
1562
1563 bool G1CollectorPolicy::is_young_list_full() const {
1564 uint young_list_length = _g1->young_list()->length();
1565 uint young_list_target_length = _young_list_target_length;
1566 return young_list_length >= young_list_target_length;
1567 }
1568
1569 bool G1CollectorPolicy::can_expand_young_list() const {
1570 uint young_list_length = _g1->young_list()->length();
1571 uint young_list_max_length = _young_list_max_length;
1572 return young_list_length < young_list_max_length;
1573 }
1574
1575 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1576 uint expansion_region_num = 0;
1577 if (GCLockerEdenExpansionPercent > 0) {
1578 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1579 double expansion_region_num_d = perc * (double) _young_list_target_length;
1580 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1581 // less than 1.0) we'll get 1.
1582 expansion_region_num = (uint) ceil(expansion_region_num_d);
1583 } else {
1584 assert(expansion_region_num == 0, "sanity");
1585 }
1586 _young_list_max_length = _young_list_target_length + expansion_region_num;
1587 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1588 }
1589
1590 // Calculates survivor space parameters.
1591 void G1CollectorPolicy::update_survivors_policy() {
1592 double max_survivor_regions_d =
1593 (double) _young_list_target_length / (double) SurvivorRatio;
1594 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1595 // smaller than 1.0) we'll get 1.
1596 _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1597
1598 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1599 HeapRegion::GrainWords * _max_survivor_regions, counters());
1600 }
1601
1602 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause) {
1603 // We actually check whether we are marking here and not if we are in a
1604 // reclamation phase. This means that we will schedule a concurrent mark
1605 // even while we are still in the process of reclaiming memory.
1606 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1607 if (!during_cycle) {
1608 ergo_verbose1(ErgoConcCycles,
1609 "request concurrent cycle initiation",
1610 ergo_format_reason("requested by GC cause")
1611 ergo_format_str("GC cause"),
1612 GCCause::to_string(gc_cause));
1613 collector_state()->set_initiate_conc_mark_if_possible(true);
1614 return true;
1615 } else {
1616 ergo_verbose1(ErgoConcCycles,
1617 "do not request concurrent cycle initiation",
1618 ergo_format_reason("concurrent cycle already in progress")
1619 ergo_format_str("GC cause"),
1620 GCCause::to_string(gc_cause));
1621 return false;
1622 }
1623 }
1624
1625 void G1CollectorPolicy::decide_on_conc_mark_initiation() {
1626 // We are about to decide on whether this pause will be an
1627 // initial-mark pause.
1628
1629 // First, collector_state()->during_initial_mark_pause() should not be already set. We
1630 // will set it here if we have to. However, it should be cleared by
1631 // the end of the pause (it's only set for the duration of an
1632 // initial-mark pause).
1633 assert(!collector_state()->during_initial_mark_pause(), "pre-condition");
1634
1635 if (collector_state()->initiate_conc_mark_if_possible()) {
1636 // We had noticed on a previous pause that the heap occupancy has
1637 // gone over the initiating threshold and we should start a
1638 // concurrent marking cycle. So we might initiate one.
1639
1640 if (!about_to_start_mixed_phase() && collector_state()->gcs_are_young()) {
1641 // Initiate a new initial mark only if there is no marking or reclamation going
1642 // on.
1643
1644 collector_state()->set_during_initial_mark_pause(true);
1645 // And we can now clear initiate_conc_mark_if_possible() as
1646 // we've already acted on it.
1647 collector_state()->set_initiate_conc_mark_if_possible(false);
1648
1649 ergo_verbose0(ErgoConcCycles,
1650 "initiate concurrent cycle",
1651 ergo_format_reason("concurrent cycle initiation requested"));
1652 } else {
1653 // The concurrent marking thread is still finishing up the
1654 // previous cycle. If we start one right now the two cycles
1655 // overlap. In particular, the concurrent marking thread might
1656 // be in the process of clearing the next marking bitmap (which
1657 // we will use for the next cycle if we start one). Starting a
1658 // cycle now will be bad given that parts of the marking
1659 // information might get cleared by the marking thread. And we
1660 // cannot wait for the marking thread to finish the cycle as it
1661 // periodically yields while clearing the next marking bitmap
1662 // and, if it's in a yield point, it's waiting for us to
1663 // finish. So, at this point we will not start a cycle and we'll
1664 // let the concurrent marking thread complete the last one.
1665 ergo_verbose0(ErgoConcCycles,
1666 "do not initiate concurrent cycle",
1667 ergo_format_reason("concurrent cycle already in progress"));
1668 }
1669 }
1670 }
1671
1672 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1673 G1CollectedHeap* _g1h;
1674 CSetChooserParUpdater _cset_updater;
1675
1676 public:
1677 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1678 uint chunk_size) :
1679 _g1h(G1CollectedHeap::heap()),
1680 _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1681
1682 bool doHeapRegion(HeapRegion* r) {
1683 // Do we have any marking information for this region?
1684 if (r->is_marked()) {
1685 // We will skip any region that's currently used as an old GC
1686 // alloc region (we should not consider those for collection
1687 // before we fill them up).
1688 if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1689 _cset_updater.add_region(r);
1690 }
1691 }
1692 return false;
1693 }
1694 };
1695
1696 class ParKnownGarbageTask: public AbstractGangTask {
1697 CollectionSetChooser* _hrSorted;
1698 uint _chunk_size;
1699 G1CollectedHeap* _g1;
1700 HeapRegionClaimer _hrclaimer;
1701
1702 public:
1703 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
1704 AbstractGangTask("ParKnownGarbageTask"),
1705 _hrSorted(hrSorted), _chunk_size(chunk_size),
1706 _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
1707
1708 void work(uint worker_id) {
1709 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1710 _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
1711 }
1712 };
1713
1714 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const {
1715 assert(n_workers > 0, "Active gc workers should be greater than 0");
1716 const uint overpartition_factor = 4;
1717 const uint min_chunk_size = MAX2(n_regions / n_workers, 1U);
1718 return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size);
1719 }
1720
1721 void
1722 G1CollectorPolicy::record_concurrent_mark_cleanup_end() {
1723 _collectionSetChooser->clear();
1724
1725 WorkGang* workers = _g1->workers();
1726 uint n_workers = workers->active_workers();
1727
1728 uint n_regions = _g1->num_regions();
1729 uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions);
1730 _collectionSetChooser->prepare_for_par_region_addition(n_workers, n_regions, chunk_size);
1731 ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers);
1732 workers->run_task(&par_known_garbage_task);
1733
1734 _collectionSetChooser->sort_regions();
1735
1736 double end_sec = os::elapsedTime();
1737 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1738 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1739 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1740 _prev_collection_pause_end_ms += elapsed_time_ms;
1741 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec);
1742 }
1743
1744 // Add the heap region at the head of the non-incremental collection set
1745 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1746 assert(_inc_cset_build_state == Active, "Precondition");
1747 assert(hr->is_old(), "the region should be old");
1748
1749 assert(!hr->in_collection_set(), "should not already be in the CSet");
1750 _g1->register_old_region_with_cset(hr);
1751 hr->set_next_in_collection_set(_collection_set);
1752 _collection_set = hr;
1753 _collection_set_bytes_used_before += hr->used();
1754 size_t rs_length = hr->rem_set()->occupied();
1755 _recorded_rs_lengths += rs_length;
1756 _old_cset_region_length += 1;
1757 }
1758
1759 // Initialize the per-collection-set information
1760 void G1CollectorPolicy::start_incremental_cset_building() {
1761 assert(_inc_cset_build_state == Inactive, "Precondition");
1762
1763 _inc_cset_head = NULL;
1764 _inc_cset_tail = NULL;
1765 _inc_cset_bytes_used_before = 0;
1766
1767 _inc_cset_max_finger = 0;
1768 _inc_cset_recorded_rs_lengths = 0;
1769 _inc_cset_recorded_rs_lengths_diffs = 0;
1770 _inc_cset_predicted_elapsed_time_ms = 0.0;
1771 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1772 _inc_cset_build_state = Active;
1773 }
1774
1775 void G1CollectorPolicy::finalize_incremental_cset_building() {
1776 assert(_inc_cset_build_state == Active, "Precondition");
1777 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1778
1779 // The two "main" fields, _inc_cset_recorded_rs_lengths and
1780 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1781 // that adds a new region to the CSet. Further updates by the
1782 // concurrent refinement thread that samples the young RSet lengths
1783 // are accumulated in the *_diffs fields. Here we add the diffs to
1784 // the "main" fields.
1785
1786 if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1787 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1788 } else {
1789 // This is defensive. The diff should in theory be always positive
1790 // as RSets can only grow between GCs. However, given that we
1791 // sample their size concurrently with other threads updating them
1792 // it's possible that we might get the wrong size back, which
1793 // could make the calculations somewhat inaccurate.
1794 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1795 if (_inc_cset_recorded_rs_lengths >= diffs) {
1796 _inc_cset_recorded_rs_lengths -= diffs;
1797 } else {
1798 _inc_cset_recorded_rs_lengths = 0;
1799 }
1800 }
1801 _inc_cset_predicted_elapsed_time_ms +=
1802 _inc_cset_predicted_elapsed_time_ms_diffs;
1803
1804 _inc_cset_recorded_rs_lengths_diffs = 0;
1805 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1806 }
1807
1808 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1809 // This routine is used when:
1810 // * adding survivor regions to the incremental cset at the end of an
1811 // evacuation pause,
1812 // * adding the current allocation region to the incremental cset
1813 // when it is retired, and
1814 // * updating existing policy information for a region in the
1815 // incremental cset via young list RSet sampling.
1816 // Therefore this routine may be called at a safepoint by the
1817 // VM thread, or in-between safepoints by mutator threads (when
1818 // retiring the current allocation region) or a concurrent
1819 // refine thread (RSet sampling).
1820
1821 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1822 size_t used_bytes = hr->used();
1823 _inc_cset_recorded_rs_lengths += rs_length;
1824 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1825 _inc_cset_bytes_used_before += used_bytes;
1826
1827 // Cache the values we have added to the aggregated information
1828 // in the heap region in case we have to remove this region from
1829 // the incremental collection set, or it is updated by the
1830 // rset sampling code
1831 hr->set_recorded_rs_length(rs_length);
1832 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1833 }
1834
1835 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1836 size_t new_rs_length) {
1837 // Update the CSet information that is dependent on the new RS length
1838 assert(hr->is_young(), "Precondition");
1839 assert(!SafepointSynchronize::is_at_safepoint(),
1840 "should not be at a safepoint");
1841
1842 // We could have updated _inc_cset_recorded_rs_lengths and
1843 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1844 // that atomically, as this code is executed by a concurrent
1845 // refinement thread, potentially concurrently with a mutator thread
1846 // allocating a new region and also updating the same fields. To
1847 // avoid the atomic operations we accumulate these updates on two
1848 // separate fields (*_diffs) and we'll just add them to the "main"
1849 // fields at the start of a GC.
1850
1851 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1852 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1853 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1854
1855 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1856 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1857 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1858 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1859
1860 hr->set_recorded_rs_length(new_rs_length);
1861 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1862 }
1863
1864 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1865 assert(hr->is_young(), "invariant");
1866 assert(hr->young_index_in_cset() > -1, "should have already been set");
1867 assert(_inc_cset_build_state == Active, "Precondition");
1868
1869 // We need to clear and set the cached recorded/cached collection set
1870 // information in the heap region here (before the region gets added
1871 // to the collection set). An individual heap region's cached values
1872 // are calculated, aggregated with the policy collection set info,
1873 // and cached in the heap region here (initially) and (subsequently)
1874 // by the Young List sampling code.
1875
1876 size_t rs_length = hr->rem_set()->occupied();
1877 add_to_incremental_cset_info(hr, rs_length);
1878
1879 HeapWord* hr_end = hr->end();
1880 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1881
1882 assert(!hr->in_collection_set(), "invariant");
1883 _g1->register_young_region_with_cset(hr);
1884 assert(hr->next_in_collection_set() == NULL, "invariant");
1885 }
1886
1887 // Add the region at the RHS of the incremental cset
1888 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1889 // We should only ever be appending survivors at the end of a pause
1890 assert(hr->is_survivor(), "Logic");
1891
1892 // Do the 'common' stuff
1893 add_region_to_incremental_cset_common(hr);
1894
1895 // Now add the region at the right hand side
1896 if (_inc_cset_tail == NULL) {
1897 assert(_inc_cset_head == NULL, "invariant");
1898 _inc_cset_head = hr;
1899 } else {
1900 _inc_cset_tail->set_next_in_collection_set(hr);
1901 }
1902 _inc_cset_tail = hr;
1903 }
1904
1905 // Add the region to the LHS of the incremental cset
1906 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1907 // Survivors should be added to the RHS at the end of a pause
1908 assert(hr->is_eden(), "Logic");
1909
1910 // Do the 'common' stuff
1911 add_region_to_incremental_cset_common(hr);
1912
1913 // Add the region at the left hand side
1914 hr->set_next_in_collection_set(_inc_cset_head);
1915 if (_inc_cset_head == NULL) {
1916 assert(_inc_cset_tail == NULL, "Invariant");
1917 _inc_cset_tail = hr;
1918 }
1919 _inc_cset_head = hr;
1920 }
1921
1922 #ifndef PRODUCT
1923 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1924 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1925
1926 st->print_cr("\nCollection_set:");
1927 HeapRegion* csr = list_head;
1928 while (csr != NULL) {
1929 HeapRegion* next = csr->next_in_collection_set();
1930 assert(csr->in_collection_set(), "bad CS");
1931 st->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d",
1932 HR_FORMAT_PARAMS(csr),
1933 p2i(csr->prev_top_at_mark_start()), p2i(csr->next_top_at_mark_start()),
1934 csr->age_in_surv_rate_group_cond());
1935 csr = next;
1936 }
1937 }
1938 #endif // !PRODUCT
1939
1940 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) const {
1941 // Returns the given amount of reclaimable bytes (that represents
1942 // the amount of reclaimable space still to be collected) as a
1943 // percentage of the current heap capacity.
1944 size_t capacity_bytes = _g1->capacity();
1945 return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1946 }
1947
1948 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1949 const char* false_action_str) const {
1950 CollectionSetChooser* cset_chooser = _collectionSetChooser;
1951 if (cset_chooser->is_empty()) {
1952 ergo_verbose0(ErgoMixedGCs,
1953 false_action_str,
1954 ergo_format_reason("candidate old regions not available"));
1955 return false;
1956 }
1957
1958 // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1959 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1960 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1961 double threshold = (double) G1HeapWastePercent;
1962 if (reclaimable_perc <= threshold) {
1963 ergo_verbose4(ErgoMixedGCs,
1964 false_action_str,
1965 ergo_format_reason("reclaimable percentage not over threshold")
1966 ergo_format_region("candidate old regions")
1967 ergo_format_byte_perc("reclaimable")
1968 ergo_format_perc("threshold"),
1969 cset_chooser->remaining_regions(),
1970 reclaimable_bytes,
1971 reclaimable_perc, threshold);
1972 return false;
1973 }
1974
1975 ergo_verbose4(ErgoMixedGCs,
1976 true_action_str,
1977 ergo_format_reason("candidate old regions available")
1978 ergo_format_region("candidate old regions")
1979 ergo_format_byte_perc("reclaimable")
1980 ergo_format_perc("threshold"),
1981 cset_chooser->remaining_regions(),
1982 reclaimable_bytes,
1983 reclaimable_perc, threshold);
1984 return true;
1985 }
1986
1987 uint G1CollectorPolicy::calc_min_old_cset_length() const {
1988 // The min old CSet region bound is based on the maximum desired
1989 // number of mixed GCs after a cycle. I.e., even if some old regions
1990 // look expensive, we should add them to the CSet anyway to make
1991 // sure we go through the available old regions in no more than the
1992 // maximum desired number of mixed GCs.
1993 //
1994 // The calculation is based on the number of marked regions we added
1995 // to the CSet chooser in the first place, not how many remain, so
1996 // that the result is the same during all mixed GCs that follow a cycle.
1997
1998 const size_t region_num = (size_t) _collectionSetChooser->length();
1999 const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
2000 size_t result = region_num / gc_num;
2001 // emulate ceiling
2002 if (result * gc_num < region_num) {
2003 result += 1;
2004 }
2005 return (uint) result;
2006 }
2007
2008 uint G1CollectorPolicy::calc_max_old_cset_length() const {
2009 // The max old CSet region bound is based on the threshold expressed
2010 // as a percentage of the heap size. I.e., it should bound the
2011 // number of old regions added to the CSet irrespective of how many
2012 // of them are available.
2013
2014 const G1CollectedHeap* g1h = G1CollectedHeap::heap();
2015 const size_t region_num = g1h->num_regions();
2016 const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
2017 size_t result = region_num * perc / 100;
2018 // emulate ceiling
2019 if (100 * result < region_num * perc) {
2020 result += 1;
2021 }
2022 return (uint) result;
2023 }
2024
2025
2026 double G1CollectorPolicy::finalize_young_cset_part(double target_pause_time_ms) {
2027 double young_start_time_sec = os::elapsedTime();
2028
2029 YoungList* young_list = _g1->young_list();
2030 finalize_incremental_cset_building();
2031
2032 guarantee(target_pause_time_ms > 0.0,
2033 "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms);
2034 guarantee(_collection_set == NULL, "Precondition");
2035
2036 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2037 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
2038
2039 ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
2040 "start choosing CSet",
2041 ergo_format_size("_pending_cards")
2042 ergo_format_ms("predicted base time")
2043 ergo_format_ms("remaining time")
2044 ergo_format_ms("target pause time"),
2045 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
2046
2047 collector_state()->set_last_gc_was_young(collector_state()->gcs_are_young());
2048
2049 if (collector_state()->last_gc_was_young()) {
2050 _trace_young_gen_time_data.increment_young_collection_count();
2051 } else {
2052 _trace_young_gen_time_data.increment_mixed_collection_count();
2053 }
2054
2055 // The young list is laid with the survivor regions from the previous
2056 // pause are appended to the RHS of the young list, i.e.
2057 // [Newly Young Regions ++ Survivors from last pause].
2058
2059 uint survivor_region_length = young_list->survivor_length();
2060 uint eden_region_length = young_list->eden_length();
2061 init_cset_region_lengths(eden_region_length, survivor_region_length);
2062
2063 HeapRegion* hr = young_list->first_survivor_region();
2064 while (hr != NULL) {
2065 assert(hr->is_survivor(), "badly formed young list");
2066 // There is a convention that all the young regions in the CSet
2067 // are tagged as "eden", so we do this for the survivors here. We
2068 // use the special set_eden_pre_gc() as it doesn't check that the
2069 // region is free (which is not the case here).
2070 hr->set_eden_pre_gc();
2071 hr = hr->get_next_young_region();
2072 }
2073
2074 // Clear the fields that point to the survivor list - they are all young now.
2075 young_list->clear_survivors();
2076
2077 _collection_set = _inc_cset_head;
2078 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2079 time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
2080
2081 ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
2082 "add young regions to CSet",
2083 ergo_format_region("eden")
2084 ergo_format_region("survivors")
2085 ergo_format_ms("predicted young region time")
2086 ergo_format_ms("target pause time"),
2087 eden_region_length, survivor_region_length,
2088 _inc_cset_predicted_elapsed_time_ms,
2089 target_pause_time_ms);
2090
2091 // The number of recorded young regions is the incremental
2092 // collection set's current size
2093 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2094
2095 double young_end_time_sec = os::elapsedTime();
2096 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
2097
2098 return time_remaining_ms;
2099 }
2100
2101 void G1CollectorPolicy::finalize_old_cset_part(double time_remaining_ms) {
2102 double non_young_start_time_sec = os::elapsedTime();
2103 double predicted_old_time_ms = 0.0;
2104
2105
2106 if (!collector_state()->gcs_are_young()) {
2107 CollectionSetChooser* cset_chooser = _collectionSetChooser;
2108 cset_chooser->verify();
2109 const uint min_old_cset_length = calc_min_old_cset_length();
2110 const uint max_old_cset_length = calc_max_old_cset_length();
2111
2112 uint expensive_region_num = 0;
2113 bool check_time_remaining = adaptive_young_list_length();
2114
2115 HeapRegion* hr = cset_chooser->peek();
2116 while (hr != NULL) {
2117 if (old_cset_region_length() >= max_old_cset_length) {
2118 // Added maximum number of old regions to the CSet.
2119 ergo_verbose2(ErgoCSetConstruction,
2120 "finish adding old regions to CSet",
2121 ergo_format_reason("old CSet region num reached max")
2122 ergo_format_region("old")
2123 ergo_format_region("max"),
2124 old_cset_region_length(), max_old_cset_length);
2125 break;
2126 }
2127
2128
2129 // Stop adding regions if the remaining reclaimable space is
2130 // not above G1HeapWastePercent.
2131 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
2132 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
2133 double threshold = (double) G1HeapWastePercent;
2134 if (reclaimable_perc <= threshold) {
2135 // We've added enough old regions that the amount of uncollected
2136 // reclaimable space is at or below the waste threshold. Stop
2137 // adding old regions to the CSet.
2138 ergo_verbose5(ErgoCSetConstruction,
2139 "finish adding old regions to CSet",
2140 ergo_format_reason("reclaimable percentage not over threshold")
2141 ergo_format_region("old")
2142 ergo_format_region("max")
2143 ergo_format_byte_perc("reclaimable")
2144 ergo_format_perc("threshold"),
2145 old_cset_region_length(),
2146 max_old_cset_length,
2147 reclaimable_bytes,
2148 reclaimable_perc, threshold);
2149 break;
2150 }
2151
2152 double predicted_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
2153 if (check_time_remaining) {
2154 if (predicted_time_ms > time_remaining_ms) {
2155 // Too expensive for the current CSet.
2156
2157 if (old_cset_region_length() >= min_old_cset_length) {
2158 // We have added the minimum number of old regions to the CSet,
2159 // we are done with this CSet.
2160 ergo_verbose4(ErgoCSetConstruction,
2161 "finish adding old regions to CSet",
2162 ergo_format_reason("predicted time is too high")
2163 ergo_format_ms("predicted time")
2164 ergo_format_ms("remaining time")
2165 ergo_format_region("old")
2166 ergo_format_region("min"),
2167 predicted_time_ms, time_remaining_ms,
2168 old_cset_region_length(), min_old_cset_length);
2169 break;
2170 }
2171
2172 // We'll add it anyway given that we haven't reached the
2173 // minimum number of old regions.
2174 expensive_region_num += 1;
2175 }
2176 } else {
2177 if (old_cset_region_length() >= min_old_cset_length) {
2178 // In the non-auto-tuning case, we'll finish adding regions
2179 // to the CSet if we reach the minimum.
2180 ergo_verbose2(ErgoCSetConstruction,
2181 "finish adding old regions to CSet",
2182 ergo_format_reason("old CSet region num reached min")
2183 ergo_format_region("old")
2184 ergo_format_region("min"),
2185 old_cset_region_length(), min_old_cset_length);
2186 break;
2187 }
2188 }
2189
2190 // We will add this region to the CSet.
2191 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2192 predicted_old_time_ms += predicted_time_ms;
2193 cset_chooser->pop(); // already have region via peek()
2194 _g1->old_set_remove(hr);
2195 add_old_region_to_cset(hr);
2196
2197 hr = cset_chooser->peek();
2198 }
2199 if (hr == NULL) {
2200 ergo_verbose0(ErgoCSetConstruction,
2201 "finish adding old regions to CSet",
2202 ergo_format_reason("candidate old regions not available"));
2203 }
2204
2205 if (expensive_region_num > 0) {
2206 // We print the information once here at the end, predicated on
2207 // whether we added any apparently expensive regions or not, to
2208 // avoid generating output per region.
2209 ergo_verbose4(ErgoCSetConstruction,
2210 "added expensive regions to CSet",
2211 ergo_format_reason("old CSet region num not reached min")
2212 ergo_format_region("old")
2213 ergo_format_region("expensive")
2214 ergo_format_region("min")
2215 ergo_format_ms("remaining time"),
2216 old_cset_region_length(),
2217 expensive_region_num,
2218 min_old_cset_length,
2219 time_remaining_ms);
2220 }
2221
2222 cset_chooser->verify();
2223 }
2224
2225 stop_incremental_cset_building();
2226
2227 ergo_verbose3(ErgoCSetConstruction,
2228 "finish choosing CSet",
2229 ergo_format_region("old")
2230 ergo_format_ms("predicted old region time")
2231 ergo_format_ms("time remaining"),
2232 old_cset_region_length(),
2233 predicted_old_time_ms, time_remaining_ms);
2234
2235 double non_young_end_time_sec = os::elapsedTime();
2236 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2237 }
2238
2239 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) {
2240 if(TraceYoungGenTime) {
2241 _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2242 }
2243 }
2244
2245 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) {
2246 if(TraceYoungGenTime) {
2247 _all_yield_times_ms.add(yield_time_ms);
2248 }
2249 }
2250
2251 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2252 if(TraceYoungGenTime) {
2253 _total.add(pause_time_ms);
2254 _other.add(pause_time_ms - phase_times->accounted_time_ms());
2255 _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2256 _parallel.add(phase_times->cur_collection_par_time_ms());
2257 _ext_root_scan.add(phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan));
2258 _satb_filtering.add(phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering));
2259 _update_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS));
2260 _scan_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::ScanRS));
2261 _obj_copy.add(phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy));
2262 _termination.add(phase_times->average_time_ms(G1GCPhaseTimes::Termination));
2263
2264 double parallel_known_time = phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan) +
2265 phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering) +
2266 phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS) +
2267 phase_times->average_time_ms(G1GCPhaseTimes::ScanRS) +
2268 phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy) +
2269 phase_times->average_time_ms(G1GCPhaseTimes::Termination);
2270
2271 double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2272 _parallel_other.add(parallel_other_time);
2273 _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2274 }
2275 }
2276
2277 void TraceYoungGenTimeData::increment_young_collection_count() {
2278 if(TraceYoungGenTime) {
2279 ++_young_pause_num;
2280 }
2281 }
2282
2283 void TraceYoungGenTimeData::increment_mixed_collection_count() {
2284 if(TraceYoungGenTime) {
2285 ++_mixed_pause_num;
2286 }
2287 }
2288
2289 void TraceYoungGenTimeData::print_summary(const char* str,
2290 const NumberSeq* seq) const {
2291 double sum = seq->sum();
2292 gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2293 str, sum / 1000.0, seq->avg());
2294 }
2295
2296 void TraceYoungGenTimeData::print_summary_sd(const char* str,
2297 const NumberSeq* seq) const {
2298 print_summary(str, seq);
2299 gclog_or_tty->print_cr("%45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2300 "(num", seq->num(), seq->sd(), seq->maximum());
2301 }
2302
2303 void TraceYoungGenTimeData::print() const {
2304 if (!TraceYoungGenTime) {
2305 return;
2306 }
2307
2308 gclog_or_tty->print_cr("ALL PAUSES");
2309 print_summary_sd(" Total", &_total);
2310 gclog_or_tty->cr();
2311 gclog_or_tty->cr();
2312 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num);
2313 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num);
2314 gclog_or_tty->cr();
2315
2316 gclog_or_tty->print_cr("EVACUATION PAUSES");
2317
2318 if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2319 gclog_or_tty->print_cr("none");
2320 } else {
2321 print_summary_sd(" Evacuation Pauses", &_total);
2322 print_summary(" Root Region Scan Wait", &_root_region_scan_wait);
2323 print_summary(" Parallel Time", &_parallel);
2324 print_summary(" Ext Root Scanning", &_ext_root_scan);
2325 print_summary(" SATB Filtering", &_satb_filtering);
2326 print_summary(" Update RS", &_update_rs);
2327 print_summary(" Scan RS", &_scan_rs);
2328 print_summary(" Object Copy", &_obj_copy);
2329 print_summary(" Termination", &_termination);
2330 print_summary(" Parallel Other", &_parallel_other);
2331 print_summary(" Clear CT", &_clear_ct);
2332 print_summary(" Other", &_other);
2333 }
2334 gclog_or_tty->cr();
2335
2336 gclog_or_tty->print_cr("MISC");
2337 print_summary_sd(" Stop World", &_all_stop_world_times_ms);
2338 print_summary_sd(" Yields", &_all_yield_times_ms);
2339 }
2340
2341 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) {
2342 if (TraceOldGenTime) {
2343 _all_full_gc_times.add(full_gc_time_ms);
2344 }
2345 }
2346
2347 void TraceOldGenTimeData::print() const {
2348 if (!TraceOldGenTime) {
2349 return;
2350 }
2351
2352 if (_all_full_gc_times.num() > 0) {
2353 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2354 _all_full_gc_times.num(),
2355 _all_full_gc_times.sum() / 1000.0);
2356 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2357 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2358 _all_full_gc_times.sd(),
2359 _all_full_gc_times.maximum());
2360 }
2361 }