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