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(need_to_start_conc_mark("end of Full GC", 0));
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 bool should_continue_with_reclaim = next_gc_should_be_mixed("request last young-only gc",
896 "skip last young-only gc");
897 collector_state()->set_last_young_gc(should_continue_with_reclaim);
898 collector_state()->set_in_marking_window(false);
899 }
900
901 void G1CollectorPolicy::record_concurrent_pause() {
902 if (_stop_world_start > 0.0) {
903 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
904 _trace_young_gen_time_data.record_yield_time(yield_ms);
905 }
906 }
907
908 double G1CollectorPolicy::average_time_ms(G1GCPhaseTimes::GCParPhases phase) const {
909 return phase_times()->average_time_ms(phase);
910 }
911
912 double G1CollectorPolicy::young_other_time_ms() const {
913 return phase_times()->young_cset_choice_time_ms() +
914 phase_times()->young_free_cset_time_ms();
915 }
916
917 double G1CollectorPolicy::non_young_other_time_ms() const {
918 return phase_times()->non_young_cset_choice_time_ms() +
919 phase_times()->non_young_free_cset_time_ms();
920
921 }
922
923 double G1CollectorPolicy::other_time_ms(double pause_time_ms) const {
924 return pause_time_ms -
925 average_time_ms(G1GCPhaseTimes::UpdateRS) -
926 average_time_ms(G1GCPhaseTimes::ScanRS) -
927 average_time_ms(G1GCPhaseTimes::ObjCopy) -
928 average_time_ms(G1GCPhaseTimes::Termination);
929 }
930
931 double G1CollectorPolicy::constant_other_time_ms(double pause_time_ms) const {
932 return other_time_ms(pause_time_ms) - young_other_time_ms() - non_young_other_time_ms();
933 }
934
935 bool G1CollectorPolicy::about_to_start_mixed_phase() const {
936 return _g1->concurrent_mark()->cmThread()->during_cycle() || collector_state()->last_young_gc();
937 }
938
939 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
940 if (about_to_start_mixed_phase()) {
941 return false;
942 }
943
944 size_t marking_initiating_used_threshold =
945 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
946 size_t cur_used_bytes = _g1->non_young_capacity_bytes();
947 size_t alloc_byte_size = alloc_word_size * HeapWordSize;
948
949 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
950 if (collector_state()->gcs_are_young() && !collector_state()->last_young_gc()) {
951 ergo_verbose5(ErgoConcCycles,
952 "request concurrent cycle initiation",
953 ergo_format_reason("occupancy higher than threshold")
954 ergo_format_byte("occupancy")
955 ergo_format_byte("allocation request")
956 ergo_format_byte_perc("threshold")
957 ergo_format_str("source"),
958 cur_used_bytes,
959 alloc_byte_size,
960 marking_initiating_used_threshold,
961 (double) InitiatingHeapOccupancyPercent,
962 source);
963 return true;
964 } else {
965 ergo_verbose5(ErgoConcCycles,
966 "do not request concurrent cycle initiation",
967 ergo_format_reason("still doing mixed collections")
968 ergo_format_byte("occupancy")
969 ergo_format_byte("allocation request")
970 ergo_format_byte_perc("threshold")
971 ergo_format_str("source"),
972 cur_used_bytes,
973 alloc_byte_size,
974 marking_initiating_used_threshold,
975 (double) InitiatingHeapOccupancyPercent,
976 source);
977 }
978 }
979
980 return false;
981 }
982
983 // Anything below that is considered to be zero
984 #define MIN_TIMER_GRANULARITY 0.0000001
985
986 void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, size_t cards_scanned) {
987 double end_time_sec = os::elapsedTime();
988 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
989 "otherwise, the subtraction below does not make sense");
990 size_t rs_size =
991 _cur_collection_pause_used_regions_at_start - cset_region_length();
992 size_t cur_used_bytes = _g1->used();
993 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
994 bool last_pause_included_initial_mark = false;
995 bool update_stats = !_g1->evacuation_failed();
996
997 #ifndef PRODUCT
998 if (G1YoungSurvRateVerbose) {
999 gclog_or_tty->cr();
1000 _short_lived_surv_rate_group->print();
1001 // do that for any other surv rate groups too
1002 }
1003 #endif // PRODUCT
1004
1005 last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
1006 if (last_pause_included_initial_mark) {
1007 record_concurrent_mark_init_end(0.0);
1008 } else {
1009 maybe_start_marking();
1010 }
1011
1012 _mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0, end_time_sec);
1013
1014 if (update_stats) {
1015 _trace_young_gen_time_data.record_end_collection(pause_time_ms, phase_times());
1016 // this is where we update the allocation rate of the application
1017 double app_time_ms =
1018 (phase_times()->cur_collection_start_sec() * 1000.0 - _prev_collection_pause_end_ms);
1019 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1020 // This usually happens due to the timer not having the required
1021 // granularity. Some Linuxes are the usual culprits.
1022 // We'll just set it to something (arbitrarily) small.
1023 app_time_ms = 1.0;
1024 }
1025 // We maintain the invariant that all objects allocated by mutator
1026 // threads will be allocated out of eden regions. So, we can use
1027 // the eden region number allocated since the previous GC to
1028 // calculate the application's allocate rate. The only exception
1029 // to that is humongous objects that are allocated separately. But
1030 // given that humongous object allocations do not really affect
1031 // either the pause's duration nor when the next pause will take
1032 // place we can safely ignore them here.
1033 uint regions_allocated = eden_cset_region_length();
1034 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1035 _alloc_rate_ms_seq->add(alloc_rate_ms);
1036
1037 double interval_ms =
1038 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1039 update_recent_gc_times(end_time_sec, pause_time_ms);
1040 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1041 if (recent_avg_pause_time_ratio() < 0.0 ||
1042 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1043 #ifndef PRODUCT
1044 // Dump info to allow post-facto debugging
1045 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1046 gclog_or_tty->print_cr("-------------------------------------------");
1047 gclog_or_tty->print_cr("Recent GC Times (ms):");
1048 _recent_gc_times_ms->dump();
1049 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1050 _recent_prev_end_times_for_all_gcs_sec->dump();
1051 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1052 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1053 // In debug mode, terminate the JVM if the user wants to debug at this point.
1054 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1055 #endif // !PRODUCT
1056 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1057 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1058 if (_recent_avg_pause_time_ratio < 0.0) {
1059 _recent_avg_pause_time_ratio = 0.0;
1060 } else {
1061 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1062 _recent_avg_pause_time_ratio = 1.0;
1063 }
1064 }
1065 }
1066
1067 bool new_in_marking_window = collector_state()->in_marking_window();
1068 bool new_in_marking_window_im = false;
1069 if (last_pause_included_initial_mark) {
1070 new_in_marking_window = true;
1071 new_in_marking_window_im = true;
1072 }
1073
1074 if (collector_state()->last_young_gc()) {
1075 // This is supposed to to be the "last young GC" before we start
1076 // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1077 assert(!last_pause_included_initial_mark, "The last young GC is not allowed to be an initial mark GC");
1078
1079 if (next_gc_should_be_mixed("start mixed GCs",
1080 "do not start mixed GCs")) {
1081 collector_state()->set_gcs_are_young(false);
1082 }
1083
1084 collector_state()->set_last_young_gc(false);
1085 }
1086
1087 if (!collector_state()->last_gc_was_young()) {
1088 // This is a mixed GC. Here we decide whether to continue doing
1089 // mixed GCs or not.
1090
1091 if (!next_gc_should_be_mixed("continue mixed GCs",
1092 "do not continue mixed GCs")) {
1093 collector_state()->set_gcs_are_young(true);
1094
1095 maybe_start_marking();
1096 }
1097 }
1098
1099 _short_lived_surv_rate_group->start_adding_regions();
1100 // Do that for any other surv rate groups
1101
1102 if (update_stats) {
1103 double cost_per_card_ms = 0.0;
1104 double cost_scan_hcc = average_time_ms(G1GCPhaseTimes::ScanHCC);
1105 if (_pending_cards > 0) {
1106 cost_per_card_ms = (average_time_ms(G1GCPhaseTimes::UpdateRS) - cost_scan_hcc) / (double) _pending_cards;
1107 _cost_per_card_ms_seq->add(cost_per_card_ms);
1108 }
1109 _cost_scan_hcc_seq->add(cost_scan_hcc);
1110
1111 double cost_per_entry_ms = 0.0;
1112 if (cards_scanned > 10) {
1113 cost_per_entry_ms = average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
1114 if (collector_state()->last_gc_was_young()) {
1115 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1116 } else {
1117 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1118 }
1119 }
1120
1121 if (_max_rs_lengths > 0) {
1122 double cards_per_entry_ratio =
1123 (double) cards_scanned / (double) _max_rs_lengths;
1124 if (collector_state()->last_gc_was_young()) {
1125 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1126 } else {
1127 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1128 }
1129 }
1130
1131 // This is defensive. For a while _max_rs_lengths could get
1132 // smaller than _recorded_rs_lengths which was causing
1133 // rs_length_diff to get very large and mess up the RSet length
1134 // predictions. The reason was unsafe concurrent updates to the
1135 // _inc_cset_recorded_rs_lengths field which the code below guards
1136 // against (see CR 7118202). This bug has now been fixed (see CR
1137 // 7119027). However, I'm still worried that
1138 // _inc_cset_recorded_rs_lengths might still end up somewhat
1139 // inaccurate. The concurrent refinement thread calculates an
1140 // RSet's length concurrently with other CR threads updating it
1141 // which might cause it to calculate the length incorrectly (if,
1142 // say, it's in mid-coarsening). So I'll leave in the defensive
1143 // conditional below just in case.
1144 size_t rs_length_diff = 0;
1145 if (_max_rs_lengths > _recorded_rs_lengths) {
1146 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1147 }
1148 _rs_length_diff_seq->add((double) rs_length_diff);
1149
1150 size_t freed_bytes = _heap_used_bytes_before_gc - cur_used_bytes;
1151 size_t copied_bytes = _collection_set_bytes_used_before - freed_bytes;
1152 double cost_per_byte_ms = 0.0;
1153
1154 if (copied_bytes > 0) {
1155 cost_per_byte_ms = average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
1156 if (collector_state()->in_marking_window()) {
1157 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1158 } else {
1159 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1160 }
1161 }
1162
1163 if (young_cset_region_length() > 0) {
1164 _young_other_cost_per_region_ms_seq->add(young_other_time_ms() /
1165 young_cset_region_length());
1166 }
1167
1168 if (old_cset_region_length() > 0) {
1169 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms() /
1170 old_cset_region_length());
1171 }
1172
1173 _constant_other_time_ms_seq->add(constant_other_time_ms(pause_time_ms));
1174
1175 _pending_cards_seq->add((double) _pending_cards);
1176 _rs_lengths_seq->add((double) _max_rs_lengths);
1177 }
1178
1179 collector_state()->set_in_marking_window(new_in_marking_window);
1180 collector_state()->set_in_marking_window_im(new_in_marking_window_im);
1181 _free_regions_at_end_of_collection = _g1->num_free_regions();
1182 update_young_list_max_and_target_length();
1183 update_rs_lengths_prediction();
1184
1185 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1186 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1187
1188 double scan_hcc_time_ms = average_time_ms(G1GCPhaseTimes::ScanHCC);
1189
1190 if (update_rs_time_goal_ms < scan_hcc_time_ms) {
1191 ergo_verbose2(ErgoTiming,
1192 "adjust concurrent refinement thresholds",
1193 ergo_format_reason("Scanning the HCC expected to take longer than Update RS time goal")
1194 ergo_format_ms("Update RS time goal")
1195 ergo_format_ms("Scan HCC time"),
1196 update_rs_time_goal_ms,
1197 scan_hcc_time_ms);
1198
1199 update_rs_time_goal_ms = 0;
1200 } else {
1201 update_rs_time_goal_ms -= scan_hcc_time_ms;
1202 }
1203 adjust_concurrent_refinement(average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms,
1204 phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS),
1205 update_rs_time_goal_ms);
1206
1207 _collectionSetChooser->verify();
1208 }
1209
1210 #define EXT_SIZE_FORMAT "%.1f%s"
1211 #define EXT_SIZE_PARAMS(bytes) \
1212 byte_size_in_proper_unit((double)(bytes)), \
1213 proper_unit_for_byte_size((bytes))
1214
1215 void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
1216 YoungList* young_list = _g1->young_list();
1217 _eden_used_bytes_before_gc = young_list->eden_used_bytes();
1218 _survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
1219 _heap_capacity_bytes_before_gc = _g1->capacity();
1220 _heap_used_bytes_before_gc = _g1->used();
1221 _cur_collection_pause_used_regions_at_start = _g1->num_used_regions();
1222
1223 _eden_capacity_bytes_before_gc =
1224 (_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
1225
1226 if (full) {
1227 _metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
1228 }
1229 }
1230
1231 void G1CollectorPolicy::print_heap_transition(size_t bytes_before) const {
1232 size_t bytes_after = _g1->used();
1233 size_t capacity = _g1->capacity();
1234
1235 gclog_or_tty->print(" " SIZE_FORMAT "%s->" SIZE_FORMAT "%s(" SIZE_FORMAT "%s)",
1236 byte_size_in_proper_unit(bytes_before),
1237 proper_unit_for_byte_size(bytes_before),
1238 byte_size_in_proper_unit(bytes_after),
1239 proper_unit_for_byte_size(bytes_after),
1240 byte_size_in_proper_unit(capacity),
1241 proper_unit_for_byte_size(capacity));
1242 }
1243
1244 void G1CollectorPolicy::print_heap_transition() const {
1245 print_heap_transition(_heap_used_bytes_before_gc);
1246 }
1247
1248 void G1CollectorPolicy::print_detailed_heap_transition(bool full) const {
1249 YoungList* young_list = _g1->young_list();
1250
1251 size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
1252 size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
1253 size_t heap_used_bytes_after_gc = _g1->used();
1254
1255 size_t heap_capacity_bytes_after_gc = _g1->capacity();
1256 size_t eden_capacity_bytes_after_gc =
1257 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
1258
1259 gclog_or_tty->print(
1260 " [Eden: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->" EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ") "
1261 "Survivors: " EXT_SIZE_FORMAT "->" EXT_SIZE_FORMAT " "
1262 "Heap: " EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")->"
1263 EXT_SIZE_FORMAT "(" EXT_SIZE_FORMAT ")]",
1264 EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
1265 EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
1266 EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
1267 EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
1268 EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
1269 EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
1270 EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
1271 EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
1272 EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
1273 EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
1274
1275 if (full) {
1276 MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
1277 }
1278
1279 gclog_or_tty->cr();
1280 }
1281
1282 void G1CollectorPolicy::print_phases(double pause_time_sec) {
1283 phase_times()->print(pause_time_sec);
1284 }
1285
1286 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1287 double update_rs_processed_buffers,
1288 double goal_ms) {
1289 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1290 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1291
1292 if (G1UseAdaptiveConcRefinement) {
1293 const int k_gy = 3, k_gr = 6;
1294 const double inc_k = 1.1, dec_k = 0.9;
1295
1296 int g = cg1r->green_zone();
1297 if (update_rs_time > goal_ms) {
1298 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1299 } else {
1300 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1301 g = (int)MAX2(g * inc_k, g + 1.0);
1302 }
1303 }
1304 // Change the refinement threads params
1305 cg1r->set_green_zone(g);
1306 cg1r->set_yellow_zone(g * k_gy);
1307 cg1r->set_red_zone(g * k_gr);
1308 cg1r->reinitialize_threads();
1309
1310 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * _predictor.sigma()), 1);
1311 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1312 cg1r->yellow_zone());
1313 // Change the barrier params
1314 dcqs.set_process_completed_threshold(processing_threshold);
1315 dcqs.set_max_completed_queue(cg1r->red_zone());
1316 }
1317
1318 int curr_queue_size = dcqs.completed_buffers_num();
1319 if (curr_queue_size >= cg1r->yellow_zone()) {
1320 dcqs.set_completed_queue_padding(curr_queue_size);
1321 } else {
1322 dcqs.set_completed_queue_padding(0);
1323 }
1324 dcqs.notify_if_necessary();
1325 }
1326
1327 size_t G1CollectorPolicy::predict_rs_length_diff() const {
1328 return (size_t) get_new_prediction(_rs_length_diff_seq);
1329 }
1330
1331 double G1CollectorPolicy::predict_alloc_rate_ms() const {
1332 return get_new_prediction(_alloc_rate_ms_seq);
1333 }
1334
1335 double G1CollectorPolicy::predict_cost_per_card_ms() const {
1336 return get_new_prediction(_cost_per_card_ms_seq);
1337 }
1338
1339 double G1CollectorPolicy::predict_scan_hcc_ms() const {
1340 return get_new_prediction(_cost_scan_hcc_seq);
1341 }
1342
1343 double G1CollectorPolicy::predict_rs_update_time_ms(size_t pending_cards) const {
1344 return pending_cards * predict_cost_per_card_ms() + predict_scan_hcc_ms();
1345 }
1346
1347 double G1CollectorPolicy::predict_young_cards_per_entry_ratio() const {
1348 return get_new_prediction(_young_cards_per_entry_ratio_seq);
1349 }
1350
1351 double G1CollectorPolicy::predict_mixed_cards_per_entry_ratio() const {
1352 if (_mixed_cards_per_entry_ratio_seq->num() < 2) {
1353 return predict_young_cards_per_entry_ratio();
1354 } else {
1355 return get_new_prediction(_mixed_cards_per_entry_ratio_seq);
1356 }
1357 }
1358
1359 size_t G1CollectorPolicy::predict_young_card_num(size_t rs_length) const {
1360 return (size_t) (rs_length * predict_young_cards_per_entry_ratio());
1361 }
1362
1363 size_t G1CollectorPolicy::predict_non_young_card_num(size_t rs_length) const {
1364 return (size_t)(rs_length * predict_mixed_cards_per_entry_ratio());
1365 }
1366
1367 double G1CollectorPolicy::predict_rs_scan_time_ms(size_t card_num) const {
1368 if (collector_state()->gcs_are_young()) {
1369 return card_num * get_new_prediction(_cost_per_entry_ms_seq);
1370 } else {
1371 return predict_mixed_rs_scan_time_ms(card_num);
1372 }
1373 }
1374
1375 double G1CollectorPolicy::predict_mixed_rs_scan_time_ms(size_t card_num) const {
1376 if (_mixed_cost_per_entry_ms_seq->num() < 3) {
1377 return card_num * get_new_prediction(_cost_per_entry_ms_seq);
1378 } else {
1379 return card_num * get_new_prediction(_mixed_cost_per_entry_ms_seq);
1380 }
1381 }
1382
1383 double G1CollectorPolicy::predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const {
1384 if (_cost_per_byte_ms_during_cm_seq->num() < 3) {
1385 return (1.1 * bytes_to_copy) * get_new_prediction(_cost_per_byte_ms_seq);
1386 } else {
1387 return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_during_cm_seq);
1388 }
1389 }
1390
1391 double G1CollectorPolicy::predict_object_copy_time_ms(size_t bytes_to_copy) const {
1392 if (collector_state()->during_concurrent_mark()) {
1393 return predict_object_copy_time_ms_during_cm(bytes_to_copy);
1394 } else {
1395 return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_seq);
1396 }
1397 }
1398
1399 double G1CollectorPolicy::predict_constant_other_time_ms() const {
1400 return get_new_prediction(_constant_other_time_ms_seq);
1401 }
1402
1403 double G1CollectorPolicy::predict_young_other_time_ms(size_t young_num) const {
1404 return young_num * get_new_prediction(_young_other_cost_per_region_ms_seq);
1405 }
1406
1407 double G1CollectorPolicy::predict_non_young_other_time_ms(size_t non_young_num) const {
1408 return non_young_num * get_new_prediction(_non_young_other_cost_per_region_ms_seq);
1409 }
1410
1411 double G1CollectorPolicy::predict_remark_time_ms() const {
1412 return get_new_prediction(_concurrent_mark_remark_times_ms);
1413 }
1414
1415 double G1CollectorPolicy::predict_cleanup_time_ms() const {
1416 return get_new_prediction(_concurrent_mark_cleanup_times_ms);
1417 }
1418
1419 double G1CollectorPolicy::predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const {
1420 TruncatedSeq* seq = surv_rate_group->get_seq(age);
1421 guarantee(seq->num() > 0, "There should be some young gen survivor samples available. Tried to access with age %d", age);
1422 double pred = get_new_prediction(seq);
1423 if (pred > 1.0) {
1424 pred = 1.0;
1425 }
1426 return pred;
1427 }
1428
1429 double G1CollectorPolicy::predict_yg_surv_rate(int age) const {
1430 return predict_yg_surv_rate(age, _short_lived_surv_rate_group);
1431 }
1432
1433 double G1CollectorPolicy::accum_yg_surv_rate_pred(int age) const {
1434 return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
1435 }
1436
1437 double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1438 size_t scanned_cards) const {
1439 return
1440 predict_rs_update_time_ms(pending_cards) +
1441 predict_rs_scan_time_ms(scanned_cards) +
1442 predict_constant_other_time_ms();
1443 }
1444
1445 double G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) const {
1446 size_t rs_length = predict_rs_length_diff();
1447 size_t card_num;
1448 if (collector_state()->gcs_are_young()) {
1449 card_num = predict_young_card_num(rs_length);
1450 } else {
1451 card_num = predict_non_young_card_num(rs_length);
1452 }
1453 return predict_base_elapsed_time_ms(pending_cards, card_num);
1454 }
1455
1456 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) const {
1457 size_t bytes_to_copy;
1458 if (hr->is_marked())
1459 bytes_to_copy = hr->max_live_bytes();
1460 else {
1461 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1462 int age = hr->age_in_surv_rate_group();
1463 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1464 bytes_to_copy = (size_t) (hr->used() * yg_surv_rate);
1465 }
1466 return bytes_to_copy;
1467 }
1468
1469 double G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1470 bool for_young_gc) const {
1471 size_t rs_length = hr->rem_set()->occupied();
1472 size_t card_num;
1473
1474 // Predicting the number of cards is based on which type of GC
1475 // we're predicting for.
1476 if (for_young_gc) {
1477 card_num = predict_young_card_num(rs_length);
1478 } else {
1479 card_num = predict_non_young_card_num(rs_length);
1480 }
1481 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1482
1483 double region_elapsed_time_ms =
1484 predict_rs_scan_time_ms(card_num) +
1485 predict_object_copy_time_ms(bytes_to_copy);
1486
1487 // The prediction of the "other" time for this region is based
1488 // upon the region type and NOT the GC type.
1489 if (hr->is_young()) {
1490 region_elapsed_time_ms += predict_young_other_time_ms(1);
1491 } else {
1492 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1493 }
1494 return region_elapsed_time_ms;
1495 }
1496
1497 void G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1498 uint survivor_cset_region_length) {
1499 _eden_cset_region_length = eden_cset_region_length;
1500 _survivor_cset_region_length = survivor_cset_region_length;
1501 _old_cset_region_length = 0;
1502 }
1503
1504 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1505 _recorded_rs_lengths = rs_lengths;
1506 }
1507
1508 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1509 double elapsed_ms) {
1510 _recent_gc_times_ms->add(elapsed_ms);
1511 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1512 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1513 }
1514
1515 size_t G1CollectorPolicy::expansion_amount() const {
1516 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1517 double threshold = _gc_overhead_perc;
1518 if (recent_gc_overhead > threshold) {
1519 // We will double the existing space, or take
1520 // G1ExpandByPercentOfAvailable % of the available expansion
1521 // space, whichever is smaller, bounded below by a minimum
1522 // expansion (unless that's all that's left.)
1523 const size_t min_expand_bytes = 1*M;
1524 size_t reserved_bytes = _g1->max_capacity();
1525 size_t committed_bytes = _g1->capacity();
1526 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1527 size_t expand_bytes;
1528 size_t expand_bytes_via_pct =
1529 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1530 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1531 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1532 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1533
1534 ergo_verbose5(ErgoHeapSizing,
1535 "attempt heap expansion",
1536 ergo_format_reason("recent GC overhead higher than "
1537 "threshold after GC")
1538 ergo_format_perc("recent GC overhead")
1539 ergo_format_perc("threshold")
1540 ergo_format_byte("uncommitted")
1541 ergo_format_byte_perc("calculated expansion amount"),
1542 recent_gc_overhead, threshold,
1543 uncommitted_bytes,
1544 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1545
1546 return expand_bytes;
1547 } else {
1548 return 0;
1549 }
1550 }
1551
1552 void G1CollectorPolicy::print_tracing_info() const {
1553 _trace_young_gen_time_data.print();
1554 _trace_old_gen_time_data.print();
1555 }
1556
1557 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1558 #ifndef PRODUCT
1559 _short_lived_surv_rate_group->print_surv_rate_summary();
1560 // add this call for any other surv rate groups
1561 #endif // PRODUCT
1562 }
1563
1564 bool G1CollectorPolicy::is_young_list_full() const {
1565 uint young_list_length = _g1->young_list()->length();
1566 uint young_list_target_length = _young_list_target_length;
1567 return young_list_length >= young_list_target_length;
1568 }
1569
1570 bool G1CollectorPolicy::can_expand_young_list() const {
1571 uint young_list_length = _g1->young_list()->length();
1572 uint young_list_max_length = _young_list_max_length;
1573 return young_list_length < young_list_max_length;
1574 }
1575
1576 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1577 uint expansion_region_num = 0;
1578 if (GCLockerEdenExpansionPercent > 0) {
1579 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1580 double expansion_region_num_d = perc * (double) _young_list_target_length;
1581 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1582 // less than 1.0) we'll get 1.
1583 expansion_region_num = (uint) ceil(expansion_region_num_d);
1584 } else {
1585 assert(expansion_region_num == 0, "sanity");
1586 }
1587 _young_list_max_length = _young_list_target_length + expansion_region_num;
1588 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1589 }
1590
1591 // Calculates survivor space parameters.
1592 void G1CollectorPolicy::update_survivors_policy() {
1593 double max_survivor_regions_d =
1594 (double) _young_list_target_length / (double) SurvivorRatio;
1595 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1596 // smaller than 1.0) we'll get 1.
1597 _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1598
1599 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1600 HeapRegion::GrainWords * _max_survivor_regions, counters());
1601 }
1602
1603 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause) {
1604 // We actually check whether we are marking here and not if we are in a
1605 // reclamation phase. This means that we will schedule a concurrent mark
1606 // even while we are still in the process of reclaiming memory.
1607 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1608 if (!during_cycle) {
1609 ergo_verbose1(ErgoConcCycles,
1610 "request concurrent cycle initiation",
1611 ergo_format_reason("requested by GC cause")
1612 ergo_format_str("GC cause"),
1613 GCCause::to_string(gc_cause));
1614 collector_state()->set_initiate_conc_mark_if_possible(true);
1615 return true;
1616 } else {
1617 ergo_verbose1(ErgoConcCycles,
1618 "do not request concurrent cycle initiation",
1619 ergo_format_reason("concurrent cycle already in progress")
1620 ergo_format_str("GC cause"),
1621 GCCause::to_string(gc_cause));
1622 return false;
1623 }
1624 }
1625
1626 void G1CollectorPolicy::decide_on_conc_mark_initiation() {
1627 // We are about to decide on whether this pause will be an
1628 // initial-mark pause.
1629
1630 // First, collector_state()->during_initial_mark_pause() should not be already set. We
1631 // will set it here if we have to. However, it should be cleared by
1632 // the end of the pause (it's only set for the duration of an
1633 // initial-mark pause).
1634 assert(!collector_state()->during_initial_mark_pause(), "pre-condition");
1635
1636 if (collector_state()->initiate_conc_mark_if_possible()) {
1637 // We had noticed on a previous pause that the heap occupancy has
1638 // gone over the initiating threshold and we should start a
1639 // concurrent marking cycle. So we might initiate one.
1640
1641 if (!about_to_start_mixed_phase() && collector_state()->gcs_are_young()) {
1642 // Initiate a new initial mark only if there is no marking or reclamation going
1643 // on.
1644
1645 collector_state()->set_during_initial_mark_pause(true);
1646 // And we can now clear initiate_conc_mark_if_possible() as
1647 // we've already acted on it.
1648 collector_state()->set_initiate_conc_mark_if_possible(false);
1649
1650 ergo_verbose0(ErgoConcCycles,
1651 "initiate concurrent cycle",
1652 ergo_format_reason("concurrent cycle initiation requested"));
1653 } else {
1654 // The concurrent marking thread is still finishing up the
1655 // previous cycle. If we start one right now the two cycles
1656 // overlap. In particular, the concurrent marking thread might
1657 // be in the process of clearing the next marking bitmap (which
1658 // we will use for the next cycle if we start one). Starting a
1659 // cycle now will be bad given that parts of the marking
1660 // information might get cleared by the marking thread. And we
1661 // cannot wait for the marking thread to finish the cycle as it
1662 // periodically yields while clearing the next marking bitmap
1663 // and, if it's in a yield point, it's waiting for us to
1664 // finish. So, at this point we will not start a cycle and we'll
1665 // let the concurrent marking thread complete the last one.
1666 ergo_verbose0(ErgoConcCycles,
1667 "do not initiate concurrent cycle",
1668 ergo_format_reason("concurrent cycle already in progress"));
1669 }
1670 }
1671 }
1672
1673 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1674 G1CollectedHeap* _g1h;
1675 CSetChooserParUpdater _cset_updater;
1676
1677 public:
1678 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1679 uint chunk_size) :
1680 _g1h(G1CollectedHeap::heap()),
1681 _cset_updater(hrSorted, true /* parallel */, chunk_size) { }
1682
1683 bool doHeapRegion(HeapRegion* r) {
1684 // Do we have any marking information for this region?
1685 if (r->is_marked()) {
1686 // We will skip any region that's currently used as an old GC
1687 // alloc region (we should not consider those for collection
1688 // before we fill them up).
1689 if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1690 _cset_updater.add_region(r);
1691 }
1692 }
1693 return false;
1694 }
1695 };
1696
1697 class ParKnownGarbageTask: public AbstractGangTask {
1698 CollectionSetChooser* _hrSorted;
1699 uint _chunk_size;
1700 G1CollectedHeap* _g1;
1701 HeapRegionClaimer _hrclaimer;
1702
1703 public:
1704 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
1705 AbstractGangTask("ParKnownGarbageTask"),
1706 _hrSorted(hrSorted), _chunk_size(chunk_size),
1707 _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
1708
1709 void work(uint worker_id) {
1710 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1711 _g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
1712 }
1713 };
1714
1715 uint G1CollectorPolicy::calculate_parallel_work_chunk_size(uint n_workers, uint n_regions) const {
1716 assert(n_workers > 0, "Active gc workers should be greater than 0");
1717 const uint overpartition_factor = 4;
1718 const uint min_chunk_size = MAX2(n_regions / n_workers, 1U);
1719 return MAX2(n_regions / (n_workers * overpartition_factor), min_chunk_size);
1720 }
1721
1722 void
1723 G1CollectorPolicy::record_concurrent_mark_cleanup_end() {
1724 _collectionSetChooser->clear();
1725
1726 WorkGang* workers = _g1->workers();
1727 uint n_workers = workers->active_workers();
1728
1729 uint n_regions = _g1->num_regions();
1730 uint chunk_size = calculate_parallel_work_chunk_size(n_workers, n_regions);
1731 _collectionSetChooser->prepare_for_par_region_addition(n_workers, n_regions, chunk_size);
1732 ParKnownGarbageTask par_known_garbage_task(_collectionSetChooser, chunk_size, n_workers);
1733 workers->run_task(&par_known_garbage_task);
1734
1735 _collectionSetChooser->sort_regions();
1736
1737 double end_sec = os::elapsedTime();
1738 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
1739 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1740 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1741 _prev_collection_pause_end_ms += elapsed_time_ms;
1742 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec);
1743 }
1744
1745 // Add the heap region at the head of the non-incremental collection set
1746 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
1747 assert(_inc_cset_build_state == Active, "Precondition");
1748 assert(hr->is_old(), "the region should be old");
1749
1750 assert(!hr->in_collection_set(), "should not already be in the CSet");
1751 _g1->register_old_region_with_cset(hr);
1752 hr->set_next_in_collection_set(_collection_set);
1753 _collection_set = hr;
1754 _collection_set_bytes_used_before += hr->used();
1755 size_t rs_length = hr->rem_set()->occupied();
1756 _recorded_rs_lengths += rs_length;
1757 _old_cset_region_length += 1;
1758 }
1759
1760 // Initialize the per-collection-set information
1761 void G1CollectorPolicy::start_incremental_cset_building() {
1762 assert(_inc_cset_build_state == Inactive, "Precondition");
1763
1764 _inc_cset_head = NULL;
1765 _inc_cset_tail = NULL;
1766 _inc_cset_bytes_used_before = 0;
1767
1768 _inc_cset_max_finger = 0;
1769 _inc_cset_recorded_rs_lengths = 0;
1770 _inc_cset_recorded_rs_lengths_diffs = 0;
1771 _inc_cset_predicted_elapsed_time_ms = 0.0;
1772 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1773 _inc_cset_build_state = Active;
1774 }
1775
1776 void G1CollectorPolicy::finalize_incremental_cset_building() {
1777 assert(_inc_cset_build_state == Active, "Precondition");
1778 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
1779
1780 // The two "main" fields, _inc_cset_recorded_rs_lengths and
1781 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
1782 // that adds a new region to the CSet. Further updates by the
1783 // concurrent refinement thread that samples the young RSet lengths
1784 // are accumulated in the *_diffs fields. Here we add the diffs to
1785 // the "main" fields.
1786
1787 if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
1788 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
1789 } else {
1790 // This is defensive. The diff should in theory be always positive
1791 // as RSets can only grow between GCs. However, given that we
1792 // sample their size concurrently with other threads updating them
1793 // it's possible that we might get the wrong size back, which
1794 // could make the calculations somewhat inaccurate.
1795 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
1796 if (_inc_cset_recorded_rs_lengths >= diffs) {
1797 _inc_cset_recorded_rs_lengths -= diffs;
1798 } else {
1799 _inc_cset_recorded_rs_lengths = 0;
1800 }
1801 }
1802 _inc_cset_predicted_elapsed_time_ms +=
1803 _inc_cset_predicted_elapsed_time_ms_diffs;
1804
1805 _inc_cset_recorded_rs_lengths_diffs = 0;
1806 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
1807 }
1808
1809 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
1810 // This routine is used when:
1811 // * adding survivor regions to the incremental cset at the end of an
1812 // evacuation pause,
1813 // * adding the current allocation region to the incremental cset
1814 // when it is retired, and
1815 // * updating existing policy information for a region in the
1816 // incremental cset via young list RSet sampling.
1817 // Therefore this routine may be called at a safepoint by the
1818 // VM thread, or in-between safepoints by mutator threads (when
1819 // retiring the current allocation region) or a concurrent
1820 // refine thread (RSet sampling).
1821
1822 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1823 size_t used_bytes = hr->used();
1824 _inc_cset_recorded_rs_lengths += rs_length;
1825 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
1826 _inc_cset_bytes_used_before += used_bytes;
1827
1828 // Cache the values we have added to the aggregated information
1829 // in the heap region in case we have to remove this region from
1830 // the incremental collection set, or it is updated by the
1831 // rset sampling code
1832 hr->set_recorded_rs_length(rs_length);
1833 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
1834 }
1835
1836 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
1837 size_t new_rs_length) {
1838 // Update the CSet information that is dependent on the new RS length
1839 assert(hr->is_young(), "Precondition");
1840 assert(!SafepointSynchronize::is_at_safepoint(),
1841 "should not be at a safepoint");
1842
1843 // We could have updated _inc_cset_recorded_rs_lengths and
1844 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
1845 // that atomically, as this code is executed by a concurrent
1846 // refinement thread, potentially concurrently with a mutator thread
1847 // allocating a new region and also updating the same fields. To
1848 // avoid the atomic operations we accumulate these updates on two
1849 // separate fields (*_diffs) and we'll just add them to the "main"
1850 // fields at the start of a GC.
1851
1852 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
1853 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
1854 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
1855
1856 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
1857 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
1858 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
1859 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
1860
1861 hr->set_recorded_rs_length(new_rs_length);
1862 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
1863 }
1864
1865 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
1866 assert(hr->is_young(), "invariant");
1867 assert(hr->young_index_in_cset() > -1, "should have already been set");
1868 assert(_inc_cset_build_state == Active, "Precondition");
1869
1870 // We need to clear and set the cached recorded/cached collection set
1871 // information in the heap region here (before the region gets added
1872 // to the collection set). An individual heap region's cached values
1873 // are calculated, aggregated with the policy collection set info,
1874 // and cached in the heap region here (initially) and (subsequently)
1875 // by the Young List sampling code.
1876
1877 size_t rs_length = hr->rem_set()->occupied();
1878 add_to_incremental_cset_info(hr, rs_length);
1879
1880 HeapWord* hr_end = hr->end();
1881 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
1882
1883 assert(!hr->in_collection_set(), "invariant");
1884 _g1->register_young_region_with_cset(hr);
1885 assert(hr->next_in_collection_set() == NULL, "invariant");
1886 }
1887
1888 // Add the region at the RHS of the incremental cset
1889 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
1890 // We should only ever be appending survivors at the end of a pause
1891 assert(hr->is_survivor(), "Logic");
1892
1893 // Do the 'common' stuff
1894 add_region_to_incremental_cset_common(hr);
1895
1896 // Now add the region at the right hand side
1897 if (_inc_cset_tail == NULL) {
1898 assert(_inc_cset_head == NULL, "invariant");
1899 _inc_cset_head = hr;
1900 } else {
1901 _inc_cset_tail->set_next_in_collection_set(hr);
1902 }
1903 _inc_cset_tail = hr;
1904 }
1905
1906 // Add the region to the LHS of the incremental cset
1907 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
1908 // Survivors should be added to the RHS at the end of a pause
1909 assert(hr->is_eden(), "Logic");
1910
1911 // Do the 'common' stuff
1912 add_region_to_incremental_cset_common(hr);
1913
1914 // Add the region at the left hand side
1915 hr->set_next_in_collection_set(_inc_cset_head);
1916 if (_inc_cset_head == NULL) {
1917 assert(_inc_cset_tail == NULL, "Invariant");
1918 _inc_cset_tail = hr;
1919 }
1920 _inc_cset_head = hr;
1921 }
1922
1923 #ifndef PRODUCT
1924 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
1925 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
1926
1927 st->print_cr("\nCollection_set:");
1928 HeapRegion* csr = list_head;
1929 while (csr != NULL) {
1930 HeapRegion* next = csr->next_in_collection_set();
1931 assert(csr->in_collection_set(), "bad CS");
1932 st->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d",
1933 HR_FORMAT_PARAMS(csr),
1934 p2i(csr->prev_top_at_mark_start()), p2i(csr->next_top_at_mark_start()),
1935 csr->age_in_surv_rate_group_cond());
1936 csr = next;
1937 }
1938 }
1939 #endif // !PRODUCT
1940
1941 double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) const {
1942 // Returns the given amount of reclaimable bytes (that represents
1943 // the amount of reclaimable space still to be collected) as a
1944 // percentage of the current heap capacity.
1945 size_t capacity_bytes = _g1->capacity();
1946 return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
1947 }
1948
1949 void G1CollectorPolicy::maybe_start_marking() {
1950 if (need_to_start_conc_mark("end of GC")) {
1951 // Note: this might have already been set, if during the last
1952 // pause we decided to start a cycle but at the beginning of
1953 // this pause we decided to postpone it. That's OK.
1954 collector_state()->set_initiate_conc_mark_if_possible(true);
1955 }
1956 }
1957
1958 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
1959 const char* false_action_str) const {
1960 CollectionSetChooser* cset_chooser = _collectionSetChooser;
1961 if (cset_chooser->is_empty()) {
1962 ergo_verbose0(ErgoMixedGCs,
1963 false_action_str,
1964 ergo_format_reason("candidate old regions not available"));
1965 return false;
1966 }
1967
1968 // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
1969 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
1970 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
1971 double threshold = (double) G1HeapWastePercent;
1972 if (reclaimable_perc <= threshold) {
1973 ergo_verbose4(ErgoMixedGCs,
1974 false_action_str,
1975 ergo_format_reason("reclaimable percentage not over threshold")
1976 ergo_format_region("candidate old regions")
1977 ergo_format_byte_perc("reclaimable")
1978 ergo_format_perc("threshold"),
1979 cset_chooser->remaining_regions(),
1980 reclaimable_bytes,
1981 reclaimable_perc, threshold);
1982 return false;
1983 }
1984
1985 ergo_verbose4(ErgoMixedGCs,
1986 true_action_str,
1987 ergo_format_reason("candidate old regions available")
1988 ergo_format_region("candidate old regions")
1989 ergo_format_byte_perc("reclaimable")
1990 ergo_format_perc("threshold"),
1991 cset_chooser->remaining_regions(),
1992 reclaimable_bytes,
1993 reclaimable_perc, threshold);
1994 return true;
1995 }
1996
1997 uint G1CollectorPolicy::calc_min_old_cset_length() const {
1998 // The min old CSet region bound is based on the maximum desired
1999 // number of mixed GCs after a cycle. I.e., even if some old regions
2000 // look expensive, we should add them to the CSet anyway to make
2001 // sure we go through the available old regions in no more than the
2002 // maximum desired number of mixed GCs.
2003 //
2004 // The calculation is based on the number of marked regions we added
2005 // to the CSet chooser in the first place, not how many remain, so
2006 // that the result is the same during all mixed GCs that follow a cycle.
2007
2008 const size_t region_num = (size_t) _collectionSetChooser->length();
2009 const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
2010 size_t result = region_num / gc_num;
2011 // emulate ceiling
2012 if (result * gc_num < region_num) {
2013 result += 1;
2014 }
2015 return (uint) result;
2016 }
2017
2018 uint G1CollectorPolicy::calc_max_old_cset_length() const {
2019 // The max old CSet region bound is based on the threshold expressed
2020 // as a percentage of the heap size. I.e., it should bound the
2021 // number of old regions added to the CSet irrespective of how many
2022 // of them are available.
2023
2024 const G1CollectedHeap* g1h = G1CollectedHeap::heap();
2025 const size_t region_num = g1h->num_regions();
2026 const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
2027 size_t result = region_num * perc / 100;
2028 // emulate ceiling
2029 if (100 * result < region_num * perc) {
2030 result += 1;
2031 }
2032 return (uint) result;
2033 }
2034
2035
2036 double G1CollectorPolicy::finalize_young_cset_part(double target_pause_time_ms) {
2037 double young_start_time_sec = os::elapsedTime();
2038
2039 YoungList* young_list = _g1->young_list();
2040 finalize_incremental_cset_building();
2041
2042 guarantee(target_pause_time_ms > 0.0,
2043 "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms);
2044 guarantee(_collection_set == NULL, "Precondition");
2045
2046 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2047 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
2048
2049 ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
2050 "start choosing CSet",
2051 ergo_format_size("_pending_cards")
2052 ergo_format_ms("predicted base time")
2053 ergo_format_ms("remaining time")
2054 ergo_format_ms("target pause time"),
2055 _pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
2056
2057 collector_state()->set_last_gc_was_young(collector_state()->gcs_are_young());
2058
2059 if (collector_state()->last_gc_was_young()) {
2060 _trace_young_gen_time_data.increment_young_collection_count();
2061 } else {
2062 _trace_young_gen_time_data.increment_mixed_collection_count();
2063 }
2064
2065 // The young list is laid with the survivor regions from the previous
2066 // pause are appended to the RHS of the young list, i.e.
2067 // [Newly Young Regions ++ Survivors from last pause].
2068
2069 uint survivor_region_length = young_list->survivor_length();
2070 uint eden_region_length = young_list->eden_length();
2071 init_cset_region_lengths(eden_region_length, survivor_region_length);
2072
2073 HeapRegion* hr = young_list->first_survivor_region();
2074 while (hr != NULL) {
2075 assert(hr->is_survivor(), "badly formed young list");
2076 // There is a convention that all the young regions in the CSet
2077 // are tagged as "eden", so we do this for the survivors here. We
2078 // use the special set_eden_pre_gc() as it doesn't check that the
2079 // region is free (which is not the case here).
2080 hr->set_eden_pre_gc();
2081 hr = hr->get_next_young_region();
2082 }
2083
2084 // Clear the fields that point to the survivor list - they are all young now.
2085 young_list->clear_survivors();
2086
2087 _collection_set = _inc_cset_head;
2088 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2089 time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
2090
2091 ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
2092 "add young regions to CSet",
2093 ergo_format_region("eden")
2094 ergo_format_region("survivors")
2095 ergo_format_ms("predicted young region time")
2096 ergo_format_ms("target pause time"),
2097 eden_region_length, survivor_region_length,
2098 _inc_cset_predicted_elapsed_time_ms,
2099 target_pause_time_ms);
2100
2101 // The number of recorded young regions is the incremental
2102 // collection set's current size
2103 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2104
2105 double young_end_time_sec = os::elapsedTime();
2106 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
2107
2108 return time_remaining_ms;
2109 }
2110
2111 void G1CollectorPolicy::finalize_old_cset_part(double time_remaining_ms) {
2112 double non_young_start_time_sec = os::elapsedTime();
2113 double predicted_old_time_ms = 0.0;
2114
2115
2116 if (!collector_state()->gcs_are_young()) {
2117 CollectionSetChooser* cset_chooser = _collectionSetChooser;
2118 cset_chooser->verify();
2119 const uint min_old_cset_length = calc_min_old_cset_length();
2120 const uint max_old_cset_length = calc_max_old_cset_length();
2121
2122 uint expensive_region_num = 0;
2123 bool check_time_remaining = adaptive_young_list_length();
2124
2125 HeapRegion* hr = cset_chooser->peek();
2126 while (hr != NULL) {
2127 if (old_cset_region_length() >= max_old_cset_length) {
2128 // Added maximum number of old regions to the CSet.
2129 ergo_verbose2(ErgoCSetConstruction,
2130 "finish adding old regions to CSet",
2131 ergo_format_reason("old CSet region num reached max")
2132 ergo_format_region("old")
2133 ergo_format_region("max"),
2134 old_cset_region_length(), max_old_cset_length);
2135 break;
2136 }
2137
2138
2139 // Stop adding regions if the remaining reclaimable space is
2140 // not above G1HeapWastePercent.
2141 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
2142 double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
2143 double threshold = (double) G1HeapWastePercent;
2144 if (reclaimable_perc <= threshold) {
2145 // We've added enough old regions that the amount of uncollected
2146 // reclaimable space is at or below the waste threshold. Stop
2147 // adding old regions to the CSet.
2148 ergo_verbose5(ErgoCSetConstruction,
2149 "finish adding old regions to CSet",
2150 ergo_format_reason("reclaimable percentage not over threshold")
2151 ergo_format_region("old")
2152 ergo_format_region("max")
2153 ergo_format_byte_perc("reclaimable")
2154 ergo_format_perc("threshold"),
2155 old_cset_region_length(),
2156 max_old_cset_length,
2157 reclaimable_bytes,
2158 reclaimable_perc, threshold);
2159 break;
2160 }
2161
2162 double predicted_time_ms = predict_region_elapsed_time_ms(hr, collector_state()->gcs_are_young());
2163 if (check_time_remaining) {
2164 if (predicted_time_ms > time_remaining_ms) {
2165 // Too expensive for the current CSet.
2166
2167 if (old_cset_region_length() >= min_old_cset_length) {
2168 // We have added the minimum number of old regions to the CSet,
2169 // we are done with this CSet.
2170 ergo_verbose4(ErgoCSetConstruction,
2171 "finish adding old regions to CSet",
2172 ergo_format_reason("predicted time is too high")
2173 ergo_format_ms("predicted time")
2174 ergo_format_ms("remaining time")
2175 ergo_format_region("old")
2176 ergo_format_region("min"),
2177 predicted_time_ms, time_remaining_ms,
2178 old_cset_region_length(), min_old_cset_length);
2179 break;
2180 }
2181
2182 // We'll add it anyway given that we haven't reached the
2183 // minimum number of old regions.
2184 expensive_region_num += 1;
2185 }
2186 } else {
2187 if (old_cset_region_length() >= min_old_cset_length) {
2188 // In the non-auto-tuning case, we'll finish adding regions
2189 // to the CSet if we reach the minimum.
2190 ergo_verbose2(ErgoCSetConstruction,
2191 "finish adding old regions to CSet",
2192 ergo_format_reason("old CSet region num reached min")
2193 ergo_format_region("old")
2194 ergo_format_region("min"),
2195 old_cset_region_length(), min_old_cset_length);
2196 break;
2197 }
2198 }
2199
2200 // We will add this region to the CSet.
2201 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
2202 predicted_old_time_ms += predicted_time_ms;
2203 cset_chooser->pop(); // already have region via peek()
2204 _g1->old_set_remove(hr);
2205 add_old_region_to_cset(hr);
2206
2207 hr = cset_chooser->peek();
2208 }
2209 if (hr == NULL) {
2210 ergo_verbose0(ErgoCSetConstruction,
2211 "finish adding old regions to CSet",
2212 ergo_format_reason("candidate old regions not available"));
2213 }
2214
2215 if (expensive_region_num > 0) {
2216 // We print the information once here at the end, predicated on
2217 // whether we added any apparently expensive regions or not, to
2218 // avoid generating output per region.
2219 ergo_verbose4(ErgoCSetConstruction,
2220 "added expensive regions to CSet",
2221 ergo_format_reason("old CSet region num not reached min")
2222 ergo_format_region("old")
2223 ergo_format_region("expensive")
2224 ergo_format_region("min")
2225 ergo_format_ms("remaining time"),
2226 old_cset_region_length(),
2227 expensive_region_num,
2228 min_old_cset_length,
2229 time_remaining_ms);
2230 }
2231
2232 cset_chooser->verify();
2233 }
2234
2235 stop_incremental_cset_building();
2236
2237 ergo_verbose3(ErgoCSetConstruction,
2238 "finish choosing CSet",
2239 ergo_format_region("old")
2240 ergo_format_ms("predicted old region time")
2241 ergo_format_ms("time remaining"),
2242 old_cset_region_length(),
2243 predicted_old_time_ms, time_remaining_ms);
2244
2245 double non_young_end_time_sec = os::elapsedTime();
2246 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
2247 }
2248
2249 void TraceYoungGenTimeData::record_start_collection(double time_to_stop_the_world_ms) {
2250 if(TraceYoungGenTime) {
2251 _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2252 }
2253 }
2254
2255 void TraceYoungGenTimeData::record_yield_time(double yield_time_ms) {
2256 if(TraceYoungGenTime) {
2257 _all_yield_times_ms.add(yield_time_ms);
2258 }
2259 }
2260
2261 void TraceYoungGenTimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
2262 if(TraceYoungGenTime) {
2263 _total.add(pause_time_ms);
2264 _other.add(pause_time_ms - phase_times->accounted_time_ms());
2265 _root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
2266 _parallel.add(phase_times->cur_collection_par_time_ms());
2267 _ext_root_scan.add(phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan));
2268 _satb_filtering.add(phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering));
2269 _update_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS));
2270 _scan_rs.add(phase_times->average_time_ms(G1GCPhaseTimes::ScanRS));
2271 _obj_copy.add(phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy));
2272 _termination.add(phase_times->average_time_ms(G1GCPhaseTimes::Termination));
2273
2274 double parallel_known_time = phase_times->average_time_ms(G1GCPhaseTimes::ExtRootScan) +
2275 phase_times->average_time_ms(G1GCPhaseTimes::SATBFiltering) +
2276 phase_times->average_time_ms(G1GCPhaseTimes::UpdateRS) +
2277 phase_times->average_time_ms(G1GCPhaseTimes::ScanRS) +
2278 phase_times->average_time_ms(G1GCPhaseTimes::ObjCopy) +
2279 phase_times->average_time_ms(G1GCPhaseTimes::Termination);
2280
2281 double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
2282 _parallel_other.add(parallel_other_time);
2283 _clear_ct.add(phase_times->cur_clear_ct_time_ms());
2284 }
2285 }
2286
2287 void TraceYoungGenTimeData::increment_young_collection_count() {
2288 if(TraceYoungGenTime) {
2289 ++_young_pause_num;
2290 }
2291 }
2292
2293 void TraceYoungGenTimeData::increment_mixed_collection_count() {
2294 if(TraceYoungGenTime) {
2295 ++_mixed_pause_num;
2296 }
2297 }
2298
2299 void TraceYoungGenTimeData::print_summary(const char* str,
2300 const NumberSeq* seq) const {
2301 double sum = seq->sum();
2302 gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
2303 str, sum / 1000.0, seq->avg());
2304 }
2305
2306 void TraceYoungGenTimeData::print_summary_sd(const char* str,
2307 const NumberSeq* seq) const {
2308 print_summary(str, seq);
2309 gclog_or_tty->print_cr("%45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2310 "(num", seq->num(), seq->sd(), seq->maximum());
2311 }
2312
2313 void TraceYoungGenTimeData::print() const {
2314 if (!TraceYoungGenTime) {
2315 return;
2316 }
2317
2318 gclog_or_tty->print_cr("ALL PAUSES");
2319 print_summary_sd(" Total", &_total);
2320 gclog_or_tty->cr();
2321 gclog_or_tty->cr();
2322 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num);
2323 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num);
2324 gclog_or_tty->cr();
2325
2326 gclog_or_tty->print_cr("EVACUATION PAUSES");
2327
2328 if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2329 gclog_or_tty->print_cr("none");
2330 } else {
2331 print_summary_sd(" Evacuation Pauses", &_total);
2332 print_summary(" Root Region Scan Wait", &_root_region_scan_wait);
2333 print_summary(" Parallel Time", &_parallel);
2334 print_summary(" Ext Root Scanning", &_ext_root_scan);
2335 print_summary(" SATB Filtering", &_satb_filtering);
2336 print_summary(" Update RS", &_update_rs);
2337 print_summary(" Scan RS", &_scan_rs);
2338 print_summary(" Object Copy", &_obj_copy);
2339 print_summary(" Termination", &_termination);
2340 print_summary(" Parallel Other", &_parallel_other);
2341 print_summary(" Clear CT", &_clear_ct);
2342 print_summary(" Other", &_other);
2343 }
2344 gclog_or_tty->cr();
2345
2346 gclog_or_tty->print_cr("MISC");
2347 print_summary_sd(" Stop World", &_all_stop_world_times_ms);
2348 print_summary_sd(" Yields", &_all_yield_times_ms);
2349 }
2350
2351 void TraceOldGenTimeData::record_full_collection(double full_gc_time_ms) {
2352 if (TraceOldGenTime) {
2353 _all_full_gc_times.add(full_gc_time_ms);
2354 }
2355 }
2356
2357 void TraceOldGenTimeData::print() const {
2358 if (!TraceOldGenTime) {
2359 return;
2360 }
2361
2362 if (_all_full_gc_times.num() > 0) {
2363 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2364 _all_full_gc_times.num(),
2365 _all_full_gc_times.sum() / 1000.0);
2366 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2367 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2368 _all_full_gc_times.sd(),
2369 _all_full_gc_times.maximum());
2370 }
2371 }