1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/concurrentG1Refine.hpp"
27 #include "gc_implementation/g1/concurrentMark.hpp"
28 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
30 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
31 #include "gc_implementation/g1/g1ErgoVerbose.hpp"
32 #include "gc_implementation/g1/g1Log.hpp"
33 #include "gc_implementation/g1/heapRegionRemSet.hpp"
34 #include "gc_implementation/shared/gcPolicyCounters.hpp"
35 #include "runtime/arguments.hpp"
36 #include "runtime/java.hpp"
37 #include "runtime/mutexLocker.hpp"
38 #include "utilities/debug.hpp"
39
40 // Different defaults for different number of GC threads
41 // They were chosen by running GCOld and SPECjbb on debris with different
42 // numbers of GC threads and choosing them based on the results
43
44 // all the same
45 static double rs_length_diff_defaults[] = {
46 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
47 };
48
49 static double cost_per_card_ms_defaults[] = {
50 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
51 };
52
53 // all the same
54 static double young_cards_per_entry_ratio_defaults[] = {
55 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
56 };
57
58 static double cost_per_entry_ms_defaults[] = {
59 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
60 };
61
62 static double cost_per_byte_ms_defaults[] = {
63 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
64 };
65
66 // these should be pretty consistent
67 static double constant_other_time_ms_defaults[] = {
68 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
69 };
70
71
72 static double young_other_cost_per_region_ms_defaults[] = {
73 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
74 };
75
76 static double non_young_other_cost_per_region_ms_defaults[] = {
77 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
78 };
79
80 // Help class for avoiding interleaved logging
81 class LineBuffer: public StackObj {
82
83 private:
84 static const int BUFFER_LEN = 1024;
85 static const int INDENT_CHARS = 3;
86 char _buffer[BUFFER_LEN];
87 int _indent_level;
88 int _cur;
89
90 void vappend(const char* format, va_list ap) {
91 int res = vsnprintf(&_buffer[_cur], BUFFER_LEN - _cur, format, ap);
92 if (res != -1) {
93 _cur += res;
94 } else {
95 DEBUG_ONLY(warning("buffer too small in LineBuffer");)
96 _buffer[BUFFER_LEN -1] = 0;
97 _cur = BUFFER_LEN; // vsnprintf above should not add to _buffer if we are called again
98 }
99 }
100
101 public:
102 explicit LineBuffer(int indent_level): _indent_level(indent_level), _cur(0) {
103 for (; (_cur < BUFFER_LEN && _cur < (_indent_level * INDENT_CHARS)); _cur++) {
104 _buffer[_cur] = ' ';
105 }
106 }
107
108 #ifndef PRODUCT
109 ~LineBuffer() {
110 assert(_cur == _indent_level * INDENT_CHARS, "pending data in buffer - append_and_print_cr() not called?");
111 }
112 #endif
113
114 void append(const char* format, ...) {
115 va_list ap;
116 va_start(ap, format);
117 vappend(format, ap);
118 va_end(ap);
119 }
120
121 void append_and_print_cr(const char* format, ...) {
122 va_list ap;
123 va_start(ap, format);
124 vappend(format, ap);
125 va_end(ap);
126 gclog_or_tty->print_cr("%s", _buffer);
127 _cur = _indent_level * INDENT_CHARS;
128 }
129 };
130
131 G1CollectorPolicy::G1CollectorPolicy() :
132 _parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads()
133 ? ParallelGCThreads : 1),
134
135 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
136 _stop_world_start(0.0),
137
138 _cur_clear_ct_time_ms(0.0),
139 _root_region_scan_wait_time_ms(0.0),
140
141 _cur_ref_proc_time_ms(0.0),
142 _cur_ref_enq_time_ms(0.0),
143
144 #ifndef PRODUCT
145 _min_clear_cc_time_ms(-1.0),
146 _max_clear_cc_time_ms(-1.0),
147 _cur_clear_cc_time_ms(0.0),
148 _cum_clear_cc_time_ms(0.0),
149 _num_cc_clears(0L),
150 #endif
151
152 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
153 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
154
155 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
156 _prev_collection_pause_end_ms(0.0),
157 _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
158 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
159 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
160 _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
161 _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
162 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
163 _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
164 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
165 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
166 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
167 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
168 _non_young_other_cost_per_region_ms_seq(
169 new TruncatedSeq(TruncatedSeqLength)),
170
171 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
172 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
173
174 _pause_time_target_ms((double) MaxGCPauseMillis),
175
176 _gcs_are_young(true),
177 _young_pause_num(0),
178 _mixed_pause_num(0),
179
180 _during_marking(false),
181 _in_marking_window(false),
182 _in_marking_window_im(false),
183
184 _recent_prev_end_times_for_all_gcs_sec(
185 new TruncatedSeq(NumPrevPausesForHeuristics)),
186
187 _recent_avg_pause_time_ratio(0.0),
188
189 _initiate_conc_mark_if_possible(false),
190 _during_initial_mark_pause(false),
191 _last_young_gc(false),
192 _last_gc_was_young(false),
193
194 _eden_bytes_before_gc(0),
195 _survivor_bytes_before_gc(0),
196 _capacity_before_gc(0),
197
198 _eden_cset_region_length(0),
199 _survivor_cset_region_length(0),
200 _old_cset_region_length(0),
201
202 _collection_set(NULL),
203 _collection_set_bytes_used_before(0),
204
205 // Incremental CSet attributes
206 _inc_cset_build_state(Inactive),
207 _inc_cset_head(NULL),
208 _inc_cset_tail(NULL),
209 _inc_cset_bytes_used_before(0),
210 _inc_cset_max_finger(NULL),
211 _inc_cset_recorded_rs_lengths(0),
212 _inc_cset_recorded_rs_lengths_diffs(0),
213 _inc_cset_predicted_elapsed_time_ms(0.0),
214 _inc_cset_predicted_elapsed_time_ms_diffs(0.0),
215
216 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
217 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
218 #endif // _MSC_VER
219
220 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
221 G1YoungSurvRateNumRegionsSummary)),
222 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
223 G1YoungSurvRateNumRegionsSummary)),
224 // add here any more surv rate groups
225 _recorded_survivor_regions(0),
226 _recorded_survivor_head(NULL),
227 _recorded_survivor_tail(NULL),
228 _survivors_age_table(true),
229
230 _gc_overhead_perc(0.0) {
231
232 // Set up the region size and associated fields. Given that the
233 // policy is created before the heap, we have to set this up here,
234 // so it's done as soon as possible.
235 HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
236 HeapRegionRemSet::setup_remset_size();
237
238 G1ErgoVerbose::initialize();
239 if (PrintAdaptiveSizePolicy) {
240 // Currently, we only use a single switch for all the heuristics.
241 G1ErgoVerbose::set_enabled(true);
242 // Given that we don't currently have a verboseness level
243 // parameter, we'll hardcode this to high. This can be easily
244 // changed in the future.
245 G1ErgoVerbose::set_level(ErgoHigh);
246 } else {
247 G1ErgoVerbose::set_enabled(false);
248 }
249
250 // Verify PLAB sizes
251 const size_t region_size = HeapRegion::GrainWords;
252 if (YoungPLABSize > region_size || OldPLABSize > region_size) {
253 char buffer[128];
254 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT,
255 OldPLABSize > region_size ? "Old" : "Young", region_size);
256 vm_exit_during_initialization(buffer);
257 }
258
259 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
260 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
261
262 _par_last_gc_worker_start_times_ms = new double[_parallel_gc_threads];
263 _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
264 _par_last_satb_filtering_times_ms = new double[_parallel_gc_threads];
265
266 _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
267 _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
268
269 _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
270
271 _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
272
273 _par_last_termination_times_ms = new double[_parallel_gc_threads];
274 _par_last_termination_attempts = new double[_parallel_gc_threads];
275 _par_last_gc_worker_end_times_ms = new double[_parallel_gc_threads];
276 _par_last_gc_worker_times_ms = new double[_parallel_gc_threads];
277 _par_last_gc_worker_other_times_ms = new double[_parallel_gc_threads];
278
279 int index;
280 if (ParallelGCThreads == 0)
281 index = 0;
282 else if (ParallelGCThreads > 8)
283 index = 7;
284 else
285 index = ParallelGCThreads - 1;
286
287 _pending_card_diff_seq->add(0.0);
288 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
289 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
290 _young_cards_per_entry_ratio_seq->add(
291 young_cards_per_entry_ratio_defaults[index]);
292 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
293 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
294 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
295 _young_other_cost_per_region_ms_seq->add(
296 young_other_cost_per_region_ms_defaults[index]);
297 _non_young_other_cost_per_region_ms_seq->add(
298 non_young_other_cost_per_region_ms_defaults[index]);
299
300 // Below, we might need to calculate the pause time target based on
301 // the pause interval. When we do so we are going to give G1 maximum
302 // flexibility and allow it to do pauses when it needs to. So, we'll
303 // arrange that the pause interval to be pause time target + 1 to
304 // ensure that a) the pause time target is maximized with respect to
305 // the pause interval and b) we maintain the invariant that pause
306 // time target < pause interval. If the user does not want this
307 // maximum flexibility, they will have to set the pause interval
308 // explicitly.
309
310 // First make sure that, if either parameter is set, its value is
311 // reasonable.
312 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
313 if (MaxGCPauseMillis < 1) {
314 vm_exit_during_initialization("MaxGCPauseMillis should be "
315 "greater than 0");
316 }
317 }
318 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
319 if (GCPauseIntervalMillis < 1) {
320 vm_exit_during_initialization("GCPauseIntervalMillis should be "
321 "greater than 0");
322 }
323 }
324
325 // Then, if the pause time target parameter was not set, set it to
326 // the default value.
327 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
328 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
329 // The default pause time target in G1 is 200ms
330 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
331 } else {
332 // We do not allow the pause interval to be set without the
333 // pause time target
334 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
335 "without setting MaxGCPauseMillis");
336 }
337 }
338
339 // Then, if the interval parameter was not set, set it according to
340 // the pause time target (this will also deal with the case when the
341 // pause time target is the default value).
342 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
343 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
344 }
345
346 // Finally, make sure that the two parameters are consistent.
347 if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
348 char buffer[256];
349 jio_snprintf(buffer, 256,
350 "MaxGCPauseMillis (%u) should be less than "
351 "GCPauseIntervalMillis (%u)",
352 MaxGCPauseMillis, GCPauseIntervalMillis);
353 vm_exit_during_initialization(buffer);
354 }
355
356 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
357 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
358 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
359 _sigma = (double) G1ConfidencePercent / 100.0;
360
361 // start conservatively (around 50ms is about right)
362 _concurrent_mark_remark_times_ms->add(0.05);
363 _concurrent_mark_cleanup_times_ms->add(0.20);
364 _tenuring_threshold = MaxTenuringThreshold;
365 // _max_survivor_regions will be calculated by
366 // update_young_list_target_length() during initialization.
367 _max_survivor_regions = 0;
368
369 assert(GCTimeRatio > 0,
370 "we should have set it to a default value set_g1_gc_flags() "
371 "if a user set it to 0");
372 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
373
374 uintx reserve_perc = G1ReservePercent;
375 // Put an artificial ceiling on this so that it's not set to a silly value.
376 if (reserve_perc > 50) {
377 reserve_perc = 50;
378 warning("G1ReservePercent is set to a value that is too large, "
379 "it's been updated to %u", reserve_perc);
380 }
381 _reserve_factor = (double) reserve_perc / 100.0;
382 // This will be set when the heap is expanded
383 // for the first time during initialization.
384 _reserve_regions = 0;
385
386 initialize_all();
387 _collectionSetChooser = new CollectionSetChooser();
388 _young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
389 }
390
391 void G1CollectorPolicy::initialize_flags() {
392 set_min_alignment(HeapRegion::GrainBytes);
393 set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
394 if (SurvivorRatio < 1) {
395 vm_exit_during_initialization("Invalid survivor ratio specified");
396 }
397 CollectorPolicy::initialize_flags();
398 }
399
400 G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true) {
401 assert(G1DefaultMinNewGenPercent <= G1DefaultMaxNewGenPercent, "Min larger than max");
402 assert(G1DefaultMinNewGenPercent > 0 && G1DefaultMinNewGenPercent < 100, "Min out of bounds");
403 assert(G1DefaultMaxNewGenPercent > 0 && G1DefaultMaxNewGenPercent < 100, "Max out of bounds");
404
405 if (FLAG_IS_CMDLINE(NewRatio)) {
406 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
407 warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
408 } else {
409 _sizer_kind = SizerNewRatio;
410 _adaptive_size = false;
411 return;
412 }
413 }
414
415 if (FLAG_IS_CMDLINE(NewSize)) {
416 _min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
417 1U);
418 if (FLAG_IS_CMDLINE(MaxNewSize)) {
419 _max_desired_young_length =
420 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
421 1U);
422 _sizer_kind = SizerMaxAndNewSize;
423 _adaptive_size = _min_desired_young_length == _max_desired_young_length;
424 } else {
425 _sizer_kind = SizerNewSizeOnly;
426 }
427 } else if (FLAG_IS_CMDLINE(MaxNewSize)) {
428 _max_desired_young_length =
429 MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
430 1U);
431 _sizer_kind = SizerMaxNewSizeOnly;
432 }
433 }
434
435 uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
436 uint default_value = (new_number_of_heap_regions * G1DefaultMinNewGenPercent) / 100;
437 return MAX2(1U, default_value);
438 }
439
440 uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
441 uint default_value = (new_number_of_heap_regions * G1DefaultMaxNewGenPercent) / 100;
442 return MAX2(1U, default_value);
443 }
444
445 void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
446 assert(new_number_of_heap_regions > 0, "Heap must be initialized");
447
448 switch (_sizer_kind) {
449 case SizerDefaults:
450 _min_desired_young_length = calculate_default_min_length(new_number_of_heap_regions);
451 _max_desired_young_length = calculate_default_max_length(new_number_of_heap_regions);
452 break;
453 case SizerNewSizeOnly:
454 _max_desired_young_length = calculate_default_max_length(new_number_of_heap_regions);
455 _max_desired_young_length = MAX2(_min_desired_young_length, _max_desired_young_length);
456 break;
457 case SizerMaxNewSizeOnly:
458 _min_desired_young_length = calculate_default_min_length(new_number_of_heap_regions);
459 _min_desired_young_length = MIN2(_min_desired_young_length, _max_desired_young_length);
460 break;
461 case SizerMaxAndNewSize:
462 // Do nothing. Values set on the command line, don't update them at runtime.
463 break;
464 case SizerNewRatio:
465 _min_desired_young_length = new_number_of_heap_regions / (NewRatio + 1);
466 _max_desired_young_length = _min_desired_young_length;
467 break;
468 default:
469 ShouldNotReachHere();
470 }
471
472 assert(_min_desired_young_length <= _max_desired_young_length, "Invalid min/max young gen size values");
473 }
474
475 void G1CollectorPolicy::init() {
476 // Set aside an initial future to_space.
477 _g1 = G1CollectedHeap::heap();
478
479 assert(Heap_lock->owned_by_self(), "Locking discipline.");
480
481 initialize_gc_policy_counters();
482
483 if (adaptive_young_list_length()) {
484 _young_list_fixed_length = 0;
485 } else {
486 _young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
487 }
488 _free_regions_at_end_of_collection = _g1->free_regions();
489 update_young_list_target_length();
490 _prev_eden_capacity = _young_list_target_length * HeapRegion::GrainBytes;
491
492 // We may immediately start allocating regions and placing them on the
493 // collection set list. Initialize the per-collection set info
494 start_incremental_cset_building();
495 }
496
497 // Create the jstat counters for the policy.
498 void G1CollectorPolicy::initialize_gc_policy_counters() {
499 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
500 }
501
502 bool G1CollectorPolicy::predict_will_fit(uint young_length,
503 double base_time_ms,
504 uint base_free_regions,
505 double target_pause_time_ms) {
506 if (young_length >= base_free_regions) {
507 // end condition 1: not enough space for the young regions
508 return false;
509 }
510
511 double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
512 size_t bytes_to_copy =
513 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
514 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
515 double young_other_time_ms = predict_young_other_time_ms(young_length);
516 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
517 if (pause_time_ms > target_pause_time_ms) {
518 // end condition 2: prediction is over the target pause time
519 return false;
520 }
521
522 size_t free_bytes =
523 (base_free_regions - young_length) * HeapRegion::GrainBytes;
524 if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
525 // end condition 3: out-of-space (conservatively!)
526 return false;
527 }
528
529 // success!
530 return true;
531 }
532
533 void G1CollectorPolicy::record_new_heap_size(uint new_number_of_regions) {
534 // re-calculate the necessary reserve
535 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
536 // We use ceiling so that if reserve_regions_d is > 0.0 (but
537 // smaller than 1.0) we'll get 1.
538 _reserve_regions = (uint) ceil(reserve_regions_d);
539
540 _young_gen_sizer->heap_size_changed(new_number_of_regions);
541 }
542
543 uint G1CollectorPolicy::calculate_young_list_desired_min_length(
544 uint base_min_length) {
545 uint desired_min_length = 0;
546 if (adaptive_young_list_length()) {
547 if (_alloc_rate_ms_seq->num() > 3) {
548 double now_sec = os::elapsedTime();
549 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
550 double alloc_rate_ms = predict_alloc_rate_ms();
551 desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
552 } else {
553 // otherwise we don't have enough info to make the prediction
554 }
555 }
556 desired_min_length += base_min_length;
557 // make sure we don't go below any user-defined minimum bound
558 return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
559 }
560
561 uint G1CollectorPolicy::calculate_young_list_desired_max_length() {
562 // Here, we might want to also take into account any additional
563 // constraints (i.e., user-defined minimum bound). Currently, we
564 // effectively don't set this bound.
565 return _young_gen_sizer->max_desired_young_length();
566 }
567
568 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
569 if (rs_lengths == (size_t) -1) {
570 // if it's set to the default value (-1), we should predict it;
571 // otherwise, use the given value.
572 rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
573 }
574
575 // Calculate the absolute and desired min bounds.
576
577 // This is how many young regions we already have (currently: the survivors).
578 uint base_min_length = recorded_survivor_regions();
579 // This is the absolute minimum young length, which ensures that we
580 // can allocate one eden region in the worst-case.
581 uint absolute_min_length = base_min_length + 1;
582 uint desired_min_length =
583 calculate_young_list_desired_min_length(base_min_length);
584 if (desired_min_length < absolute_min_length) {
585 desired_min_length = absolute_min_length;
586 }
587
588 // Calculate the absolute and desired max bounds.
589
590 // We will try our best not to "eat" into the reserve.
591 uint absolute_max_length = 0;
592 if (_free_regions_at_end_of_collection > _reserve_regions) {
593 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
594 }
595 uint desired_max_length = calculate_young_list_desired_max_length();
596 if (desired_max_length > absolute_max_length) {
597 desired_max_length = absolute_max_length;
598 }
599
600 uint young_list_target_length = 0;
601 if (adaptive_young_list_length()) {
602 if (gcs_are_young()) {
603 young_list_target_length =
604 calculate_young_list_target_length(rs_lengths,
605 base_min_length,
606 desired_min_length,
607 desired_max_length);
608 _rs_lengths_prediction = rs_lengths;
609 } else {
610 // Don't calculate anything and let the code below bound it to
611 // the desired_min_length, i.e., do the next GC as soon as
612 // possible to maximize how many old regions we can add to it.
613 }
614 } else {
615 // The user asked for a fixed young gen so we'll fix the young gen
616 // whether the next GC is young or mixed.
617 young_list_target_length = _young_list_fixed_length;
618 }
619
620 // Make sure we don't go over the desired max length, nor under the
621 // desired min length. In case they clash, desired_min_length wins
622 // which is why that test is second.
623 if (young_list_target_length > desired_max_length) {
624 young_list_target_length = desired_max_length;
625 }
626 if (young_list_target_length < desired_min_length) {
627 young_list_target_length = desired_min_length;
628 }
629
630 assert(young_list_target_length > recorded_survivor_regions(),
631 "we should be able to allocate at least one eden region");
632 assert(young_list_target_length >= absolute_min_length, "post-condition");
633 _young_list_target_length = young_list_target_length;
634
635 update_max_gc_locker_expansion();
636 }
637
638 uint
639 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
640 uint base_min_length,
641 uint desired_min_length,
642 uint desired_max_length) {
643 assert(adaptive_young_list_length(), "pre-condition");
644 assert(gcs_are_young(), "only call this for young GCs");
645
646 // In case some edge-condition makes the desired max length too small...
647 if (desired_max_length <= desired_min_length) {
648 return desired_min_length;
649 }
650
651 // We'll adjust min_young_length and max_young_length not to include
652 // the already allocated young regions (i.e., so they reflect the
653 // min and max eden regions we'll allocate). The base_min_length
654 // will be reflected in the predictions by the
655 // survivor_regions_evac_time prediction.
656 assert(desired_min_length > base_min_length, "invariant");
657 uint min_young_length = desired_min_length - base_min_length;
658 assert(desired_max_length > base_min_length, "invariant");
659 uint max_young_length = desired_max_length - base_min_length;
660
661 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
662 double survivor_regions_evac_time = predict_survivor_regions_evac_time();
663 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
664 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
665 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
666 double base_time_ms =
667 predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
668 survivor_regions_evac_time;
669 uint available_free_regions = _free_regions_at_end_of_collection;
670 uint base_free_regions = 0;
671 if (available_free_regions > _reserve_regions) {
672 base_free_regions = available_free_regions - _reserve_regions;
673 }
674
675 // Here, we will make sure that the shortest young length that
676 // makes sense fits within the target pause time.
677
678 if (predict_will_fit(min_young_length, base_time_ms,
679 base_free_regions, target_pause_time_ms)) {
680 // The shortest young length will fit into the target pause time;
681 // we'll now check whether the absolute maximum number of young
682 // regions will fit in the target pause time. If not, we'll do
683 // a binary search between min_young_length and max_young_length.
684 if (predict_will_fit(max_young_length, base_time_ms,
685 base_free_regions, target_pause_time_ms)) {
686 // The maximum young length will fit into the target pause time.
687 // We are done so set min young length to the maximum length (as
688 // the result is assumed to be returned in min_young_length).
689 min_young_length = max_young_length;
690 } else {
691 // The maximum possible number of young regions will not fit within
692 // the target pause time so we'll search for the optimal
693 // length. The loop invariants are:
694 //
695 // min_young_length < max_young_length
696 // min_young_length is known to fit into the target pause time
697 // max_young_length is known not to fit into the target pause time
698 //
699 // Going into the loop we know the above hold as we've just
700 // checked them. Every time around the loop we check whether
701 // the middle value between min_young_length and
702 // max_young_length fits into the target pause time. If it
703 // does, it becomes the new min. If it doesn't, it becomes
704 // the new max. This way we maintain the loop invariants.
705
706 assert(min_young_length < max_young_length, "invariant");
707 uint diff = (max_young_length - min_young_length) / 2;
708 while (diff > 0) {
709 uint young_length = min_young_length + diff;
710 if (predict_will_fit(young_length, base_time_ms,
711 base_free_regions, target_pause_time_ms)) {
712 min_young_length = young_length;
713 } else {
714 max_young_length = young_length;
715 }
716 assert(min_young_length < max_young_length, "invariant");
717 diff = (max_young_length - min_young_length) / 2;
718 }
719 // The results is min_young_length which, according to the
720 // loop invariants, should fit within the target pause time.
721
722 // These are the post-conditions of the binary search above:
723 assert(min_young_length < max_young_length,
724 "otherwise we should have discovered that max_young_length "
725 "fits into the pause target and not done the binary search");
726 assert(predict_will_fit(min_young_length, base_time_ms,
727 base_free_regions, target_pause_time_ms),
728 "min_young_length, the result of the binary search, should "
729 "fit into the pause target");
730 assert(!predict_will_fit(min_young_length + 1, base_time_ms,
731 base_free_regions, target_pause_time_ms),
732 "min_young_length, the result of the binary search, should be "
733 "optimal, so no larger length should fit into the pause target");
734 }
735 } else {
736 // Even the minimum length doesn't fit into the pause time
737 // target, return it as the result nevertheless.
738 }
739 return base_min_length + min_young_length;
740 }
741
742 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
743 double survivor_regions_evac_time = 0.0;
744 for (HeapRegion * r = _recorded_survivor_head;
745 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
746 r = r->get_next_young_region()) {
747 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
748 }
749 return survivor_regions_evac_time;
750 }
751
752 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
753 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
754
755 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
756 if (rs_lengths > _rs_lengths_prediction) {
757 // add 10% to avoid having to recalculate often
758 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
759 update_young_list_target_length(rs_lengths_prediction);
760 }
761 }
762
763
764
765 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
766 bool is_tlab,
767 bool* gc_overhead_limit_was_exceeded) {
768 guarantee(false, "Not using this policy feature yet.");
769 return NULL;
770 }
771
772 // This method controls how a collector handles one or more
773 // of its generations being fully allocated.
774 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
775 bool is_tlab) {
776 guarantee(false, "Not using this policy feature yet.");
777 return NULL;
778 }
779
780
781 #ifndef PRODUCT
782 bool G1CollectorPolicy::verify_young_ages() {
783 HeapRegion* head = _g1->young_list()->first_region();
784 return
785 verify_young_ages(head, _short_lived_surv_rate_group);
786 // also call verify_young_ages on any additional surv rate groups
787 }
788
789 bool
790 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
791 SurvRateGroup *surv_rate_group) {
792 guarantee( surv_rate_group != NULL, "pre-condition" );
793
794 const char* name = surv_rate_group->name();
795 bool ret = true;
796 int prev_age = -1;
797
798 for (HeapRegion* curr = head;
799 curr != NULL;
800 curr = curr->get_next_young_region()) {
801 SurvRateGroup* group = curr->surv_rate_group();
802 if (group == NULL && !curr->is_survivor()) {
803 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
804 ret = false;
805 }
806
807 if (surv_rate_group == group) {
808 int age = curr->age_in_surv_rate_group();
809
810 if (age < 0) {
811 gclog_or_tty->print_cr("## %s: encountered negative age", name);
812 ret = false;
813 }
814
815 if (age <= prev_age) {
816 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
817 "(%d, %d)", name, age, prev_age);
818 ret = false;
819 }
820 prev_age = age;
821 }
822 }
823
824 return ret;
825 }
826 #endif // PRODUCT
827
828 void G1CollectorPolicy::record_full_collection_start() {
829 _cur_collection_start_sec = os::elapsedTime();
830 // Release the future to-space so that it is available for compaction into.
831 _g1->set_full_collection();
832 }
833
834 void G1CollectorPolicy::record_full_collection_end() {
835 // Consider this like a collection pause for the purposes of allocation
836 // since last pause.
837 double end_sec = os::elapsedTime();
838 double full_gc_time_sec = end_sec - _cur_collection_start_sec;
839 double full_gc_time_ms = full_gc_time_sec * 1000.0;
840
841 _trace_gen1_time_data.record_full_collection(full_gc_time_ms);
842
843 update_recent_gc_times(end_sec, full_gc_time_ms);
844
845 _g1->clear_full_collection();
846
847 // "Nuke" the heuristics that control the young/mixed GC
848 // transitions and make sure we start with young GCs after the Full GC.
849 set_gcs_are_young(true);
850 _last_young_gc = false;
851 clear_initiate_conc_mark_if_possible();
852 clear_during_initial_mark_pause();
853 _in_marking_window = false;
854 _in_marking_window_im = false;
855
856 _short_lived_surv_rate_group->start_adding_regions();
857 // also call this on any additional surv rate groups
858
859 record_survivor_regions(0, NULL, NULL);
860
861 _free_regions_at_end_of_collection = _g1->free_regions();
862 // Reset survivors SurvRateGroup.
863 _survivor_surv_rate_group->reset();
864 update_young_list_target_length();
865 _collectionSetChooser->clear();
866 }
867
868 void G1CollectorPolicy::record_stop_world_start() {
869 _stop_world_start = os::elapsedTime();
870 }
871
872 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
873 size_t start_used) {
874 if (G1Log::finer()) {
875 gclog_or_tty->stamp(PrintGCTimeStamps);
876 gclog_or_tty->print("[%s", (const char*)GCCauseString("GC pause", _g1->gc_cause())
877 .append(gcs_are_young() ? " (young)" : " (mixed)"));
878 }
879
880 // We only need to do this here as the policy will only be applied
881 // to the GC we're about to start. so, no point is calculating this
882 // every time we calculate / recalculate the target young length.
883 update_survivors_policy();
884
885 assert(_g1->used() == _g1->recalculate_used(),
886 err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
887 _g1->used(), _g1->recalculate_used()));
888
889 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
890 _trace_gen0_time_data.record_start_collection(s_w_t_ms);
891 _stop_world_start = 0.0;
892
893 _cur_collection_start_sec = start_time_sec;
894 _cur_collection_pause_used_at_start_bytes = start_used;
895 _cur_collection_pause_used_regions_at_start = _g1->used_regions();
896 _pending_cards = _g1->pending_card_num();
897 _max_pending_cards = _g1->max_pending_card_num();
898
899 _bytes_in_collection_set_before_gc = 0;
900 _bytes_copied_during_gc = 0;
901
902 YoungList* young_list = _g1->young_list();
903 _eden_bytes_before_gc = young_list->eden_used_bytes();
904 _survivor_bytes_before_gc = young_list->survivor_used_bytes();
905 _capacity_before_gc = _g1->capacity();
906
907 #ifdef DEBUG
908 // initialise these to something well known so that we can spot
909 // if they are not set properly
910
911 for (int i = 0; i < _parallel_gc_threads; ++i) {
912 _par_last_gc_worker_start_times_ms[i] = -1234.0;
913 _par_last_ext_root_scan_times_ms[i] = -1234.0;
914 _par_last_satb_filtering_times_ms[i] = -1234.0;
915 _par_last_update_rs_times_ms[i] = -1234.0;
916 _par_last_update_rs_processed_buffers[i] = -1234.0;
917 _par_last_scan_rs_times_ms[i] = -1234.0;
918 _par_last_obj_copy_times_ms[i] = -1234.0;
919 _par_last_termination_times_ms[i] = -1234.0;
920 _par_last_termination_attempts[i] = -1234.0;
921 _par_last_gc_worker_end_times_ms[i] = -1234.0;
922 _par_last_gc_worker_times_ms[i] = -1234.0;
923 _par_last_gc_worker_other_times_ms[i] = -1234.0;
924 }
925 #endif
926
927 // This is initialized to zero here and is set during the evacuation
928 // pause if we actually waited for the root region scanning to finish.
929 _root_region_scan_wait_time_ms = 0.0;
930
931 _last_gc_was_young = false;
932
933 // do that for any other surv rate groups
934 _short_lived_surv_rate_group->stop_adding_regions();
935 _survivors_age_table.clear();
936
937 assert( verify_young_ages(), "region age verification" );
938 }
939
940 void G1CollectorPolicy::record_concurrent_mark_init_end(double
941 mark_init_elapsed_time_ms) {
942 _during_marking = true;
943 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
944 clear_during_initial_mark_pause();
945 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
946 }
947
948 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
949 _mark_remark_start_sec = os::elapsedTime();
950 _during_marking = false;
951 }
952
953 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
954 double end_time_sec = os::elapsedTime();
955 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
956 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
957 _cur_mark_stop_world_time_ms += elapsed_time_ms;
958 _prev_collection_pause_end_ms += elapsed_time_ms;
959
960 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
961 }
962
963 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
964 _mark_cleanup_start_sec = os::elapsedTime();
965 }
966
967 void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
968 _last_young_gc = true;
969 _in_marking_window = false;
970 }
971
972 void G1CollectorPolicy::record_concurrent_pause() {
973 if (_stop_world_start > 0.0) {
974 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
975 _trace_gen0_time_data.record_yield_time(yield_ms);
976 }
977 }
978
979 void G1CollectorPolicy::record_concurrent_pause_end() {
980 }
981
982 template<class T>
983 T sum_of(T* sum_arr, int start, int n, int N) {
984 T sum = (T)0;
985 for (int i = 0; i < n; i++) {
986 int j = (start + i) % N;
987 sum += sum_arr[j];
988 }
989 return sum;
990 }
991
992 void G1CollectorPolicy::print_par_stats(int level,
993 const char* str,
994 double* data,
995 bool showDecimals) {
996 double min = data[0], max = data[0];
997 double total = 0.0;
998 LineBuffer buf(level);
999 buf.append("[%s (ms):", str);
1000 for (uint i = 0; i < no_of_gc_threads(); ++i) {
1001 double val = data[i];
1002 if (val < min)
1003 min = val;
1004 if (val > max)
1005 max = val;
1006 total += val;
1007 if (G1Log::finest()) {
1008 if (showDecimals) {
1009 buf.append(" %.1lf", val);
1010 } else {
1011 buf.append(" %d", (int)val);
1012 }
1013 }
1014 }
1015
1016 if (G1Log::finest()) {
1017 buf.append_and_print_cr("");
1018 }
1019 double avg = total / (double) no_of_gc_threads();
1020 if (showDecimals) {
1021 buf.append_and_print_cr(" Min: %.1lf, Avg: %.1lf, Max: %.1lf, Diff: %.1lf, Sum: %.1lf]",
1022 min, avg, max, max - min, total);
1023 } else {
1024 buf.append_and_print_cr(" Min: %d, Avg: %d, Max: %d, Diff: %d, Sum: %d]",
1025 (int)min, (int)avg, (int)max, (int)max - (int)min, (int)total);
1026 }
1027 }
1028
1029 void G1CollectorPolicy::print_stats(int level,
1030 const char* str,
1031 double value) {
1032 LineBuffer(level).append_and_print_cr("[%s: %.1lf ms]", str, value);
1033 }
1034
1035 void G1CollectorPolicy::print_stats(int level,
1036 const char* str,
1037 double value,
1038 int workers) {
1039 LineBuffer(level).append_and_print_cr("[%s: %.1lf ms, GC Workers: %d]", str, value, workers);
1040 }
1041
1042 void G1CollectorPolicy::print_stats(int level,
1043 const char* str,
1044 int value) {
1045 LineBuffer(level).append_and_print_cr("[%s: %d]", str, value);
1046 }
1047
1048 double G1CollectorPolicy::avg_value(double* data) {
1049 if (G1CollectedHeap::use_parallel_gc_threads()) {
1050 double ret = 0.0;
1051 for (uint i = 0; i < no_of_gc_threads(); ++i) {
1052 ret += data[i];
1053 }
1054 return ret / (double) no_of_gc_threads();
1055 } else {
1056 return data[0];
1057 }
1058 }
1059
1060 double G1CollectorPolicy::max_value(double* data) {
1061 if (G1CollectedHeap::use_parallel_gc_threads()) {
1062 double ret = data[0];
1063 for (uint i = 1; i < no_of_gc_threads(); ++i) {
1064 if (data[i] > ret) {
1065 ret = data[i];
1066 }
1067 }
1068 return ret;
1069 } else {
1070 return data[0];
1071 }
1072 }
1073
1074 double G1CollectorPolicy::sum_of_values(double* data) {
1075 if (G1CollectedHeap::use_parallel_gc_threads()) {
1076 double sum = 0.0;
1077 for (uint i = 0; i < no_of_gc_threads(); i++) {
1078 sum += data[i];
1079 }
1080 return sum;
1081 } else {
1082 return data[0];
1083 }
1084 }
1085
1086 double G1CollectorPolicy::max_sum(double* data1, double* data2) {
1087 double ret = data1[0] + data2[0];
1088
1089 if (G1CollectedHeap::use_parallel_gc_threads()) {
1090 for (uint i = 1; i < no_of_gc_threads(); ++i) {
1091 double data = data1[i] + data2[i];
1092 if (data > ret) {
1093 ret = data;
1094 }
1095 }
1096 }
1097 return ret;
1098 }
1099
1100 bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
1101 if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
1102 return false;
1103 }
1104
1105 size_t marking_initiating_used_threshold =
1106 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
1107 size_t cur_used_bytes = _g1->non_young_capacity_bytes();
1108 size_t alloc_byte_size = alloc_word_size * HeapWordSize;
1109
1110 if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
1111 if (gcs_are_young()) {
1112 ergo_verbose5(ErgoConcCycles,
1113 "request concurrent cycle initiation",
1114 ergo_format_reason("occupancy higher than threshold")
1115 ergo_format_byte("occupancy")
1116 ergo_format_byte("allocation request")
1117 ergo_format_byte_perc("threshold")
1118 ergo_format_str("source"),
1119 cur_used_bytes,
1120 alloc_byte_size,
1121 marking_initiating_used_threshold,
1122 (double) InitiatingHeapOccupancyPercent,
1123 source);
1124 return true;
1125 } else {
1126 ergo_verbose5(ErgoConcCycles,
1127 "do not request concurrent cycle initiation",
1128 ergo_format_reason("still doing mixed collections")
1129 ergo_format_byte("occupancy")
1130 ergo_format_byte("allocation request")
1131 ergo_format_byte_perc("threshold")
1132 ergo_format_str("source"),
1133 cur_used_bytes,
1134 alloc_byte_size,
1135 marking_initiating_used_threshold,
1136 (double) InitiatingHeapOccupancyPercent,
1137 source);
1138 }
1139 }
1140
1141 return false;
1142 }
1143
1144 // Anything below that is considered to be zero
1145 #define MIN_TIMER_GRANULARITY 0.0000001
1146
1147 void G1CollectorPolicy::record_collection_pause_end(int no_of_gc_threads) {
1148 double end_time_sec = os::elapsedTime();
1149 double elapsed_ms = _last_pause_time_ms;
1150 bool parallel = G1CollectedHeap::use_parallel_gc_threads();
1151 assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
1152 "otherwise, the subtraction below does not make sense");
1153 size_t rs_size =
1154 _cur_collection_pause_used_regions_at_start - cset_region_length();
1155 size_t cur_used_bytes = _g1->used();
1156 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1157 bool last_pause_included_initial_mark = false;
1158 bool update_stats = !_g1->evacuation_failed();
1159 set_no_of_gc_threads(no_of_gc_threads);
1160
1161 #ifndef PRODUCT
1162 if (G1YoungSurvRateVerbose) {
1163 gclog_or_tty->print_cr("");
1164 _short_lived_surv_rate_group->print();
1165 // do that for any other surv rate groups too
1166 }
1167 #endif // PRODUCT
1168
1169 last_pause_included_initial_mark = during_initial_mark_pause();
1170 if (last_pause_included_initial_mark) {
1171 record_concurrent_mark_init_end(0.0);
1172 } else if (!_last_young_gc && need_to_start_conc_mark("end of GC")) {
1173 // Note: this might have already been set, if during the last
1174 // pause we decided to start a cycle but at the beginning of
1175 // this pause we decided to postpone it. That's OK.
1176 set_initiate_conc_mark_if_possible();
1177 }
1178
1179 _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
1180 end_time_sec, false);
1181
1182 size_t freed_bytes =
1183 _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
1184 size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
1185
1186 double survival_fraction =
1187 (double)surviving_bytes/
1188 (double)_collection_set_bytes_used_before;
1189
1190 // These values are used to update the summary information that is
1191 // displayed when TraceGen0Time is enabled, and are output as part
1192 // of the "finer" output, in the non-parallel case.
1193
1194 double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
1195 double satb_filtering_time = avg_value(_par_last_satb_filtering_times_ms);
1196 double update_rs_time = avg_value(_par_last_update_rs_times_ms);
1197 double update_rs_processed_buffers =
1198 sum_of_values(_par_last_update_rs_processed_buffers);
1199 double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
1200 double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
1201 double termination_time = avg_value(_par_last_termination_times_ms);
1202
1203 double known_time = ext_root_scan_time +
1204 satb_filtering_time +
1205 update_rs_time +
1206 scan_rs_time +
1207 obj_copy_time;
1208
1209 double other_time_ms = elapsed_ms;
1210
1211 // Subtract the root region scanning wait time. It's initialized to
1212 // zero at the start of the pause.
1213 other_time_ms -= _root_region_scan_wait_time_ms;
1214
1215 if (parallel) {
1216 other_time_ms -= _cur_collection_par_time_ms;
1217 } else {
1218 other_time_ms -= known_time;
1219 }
1220
1221 // Now subtract the time taken to fix up roots in generated code
1222 other_time_ms -= _cur_collection_code_root_fixup_time_ms;
1223
1224 // Subtract the time taken to clean the card table from the
1225 // current value of "other time"
1226 other_time_ms -= _cur_clear_ct_time_ms;
1227
1228 // TraceGen0Time and TraceGen1Time summary info updating.
1229
1230 if (update_stats) {
1231 double parallel_known_time = known_time + termination_time;
1232 double parallel_other_time = _cur_collection_par_time_ms - parallel_known_time;
1233
1234 _trace_gen0_time_data.record_end_collection(
1235 elapsed_ms, other_time_ms, _root_region_scan_wait_time_ms, _cur_collection_par_time_ms,
1236 ext_root_scan_time, satb_filtering_time, update_rs_time, scan_rs_time, obj_copy_time,
1237 termination_time, parallel_other_time, _cur_clear_ct_time_ms);
1238
1239 // this is where we update the allocation rate of the application
1240 double app_time_ms =
1241 (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
1242 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1243 // This usually happens due to the timer not having the required
1244 // granularity. Some Linuxes are the usual culprits.
1245 // We'll just set it to something (arbitrarily) small.
1246 app_time_ms = 1.0;
1247 }
1248 // We maintain the invariant that all objects allocated by mutator
1249 // threads will be allocated out of eden regions. So, we can use
1250 // the eden region number allocated since the previous GC to
1251 // calculate the application's allocate rate. The only exception
1252 // to that is humongous objects that are allocated separately. But
1253 // given that humongous object allocations do not really affect
1254 // either the pause's duration nor when the next pause will take
1255 // place we can safely ignore them here.
1256 uint regions_allocated = eden_cset_region_length();
1257 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1258 _alloc_rate_ms_seq->add(alloc_rate_ms);
1259
1260 double interval_ms =
1261 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1262 update_recent_gc_times(end_time_sec, elapsed_ms);
1263 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1264 if (recent_avg_pause_time_ratio() < 0.0 ||
1265 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1266 #ifndef PRODUCT
1267 // Dump info to allow post-facto debugging
1268 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1269 gclog_or_tty->print_cr("-------------------------------------------");
1270 gclog_or_tty->print_cr("Recent GC Times (ms):");
1271 _recent_gc_times_ms->dump();
1272 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1273 _recent_prev_end_times_for_all_gcs_sec->dump();
1274 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1275 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1276 // In debug mode, terminate the JVM if the user wants to debug at this point.
1277 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1278 #endif // !PRODUCT
1279 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1280 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1281 if (_recent_avg_pause_time_ratio < 0.0) {
1282 _recent_avg_pause_time_ratio = 0.0;
1283 } else {
1284 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1285 _recent_avg_pause_time_ratio = 1.0;
1286 }
1287 }
1288 }
1289
1290 if (G1Log::finer()) {
1291 bool print_marking_info =
1292 _g1->mark_in_progress() && !last_pause_included_initial_mark;
1293
1294 gclog_or_tty->print_cr("%s, %1.8lf secs]",
1295 (last_pause_included_initial_mark) ? " (initial-mark)" : "",
1296 elapsed_ms / 1000.0);
1297
1298 if (_root_region_scan_wait_time_ms > 0.0) {
1299 print_stats(1, "Root Region Scan Waiting", _root_region_scan_wait_time_ms);
1300 }
1301 if (parallel) {
1302 print_stats(1, "Parallel Time", _cur_collection_par_time_ms, no_of_gc_threads);
1303 print_par_stats(2, "GC Worker Start", _par_last_gc_worker_start_times_ms);
1304 print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
1305 if (print_marking_info) {
1306 print_par_stats(2, "SATB Filtering", _par_last_satb_filtering_times_ms);
1307 }
1308 print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
1309 if (G1Log::finest()) {
1310 print_par_stats(3, "Processed Buffers", _par_last_update_rs_processed_buffers,
1311 false /* showDecimals */);
1312 }
1313 print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
1314 print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
1315 print_par_stats(2, "Termination", _par_last_termination_times_ms);
1316 if (G1Log::finest()) {
1317 print_par_stats(3, "Termination Attempts", _par_last_termination_attempts,
1318 false /* showDecimals */);
1319 }
1320
1321 for (int i = 0; i < _parallel_gc_threads; i++) {
1322 _par_last_gc_worker_times_ms[i] = _par_last_gc_worker_end_times_ms[i] -
1323 _par_last_gc_worker_start_times_ms[i];
1324
1325 double worker_known_time = _par_last_ext_root_scan_times_ms[i] +
1326 _par_last_satb_filtering_times_ms[i] +
1327 _par_last_update_rs_times_ms[i] +
1328 _par_last_scan_rs_times_ms[i] +
1329 _par_last_obj_copy_times_ms[i] +
1330 _par_last_termination_times_ms[i];
1331
1332 _par_last_gc_worker_other_times_ms[i] = _par_last_gc_worker_times_ms[i] -
1333 worker_known_time;
1334 }
1335
1336 print_par_stats(2, "GC Worker Other", _par_last_gc_worker_other_times_ms);
1337 print_par_stats(2, "GC Worker Total", _par_last_gc_worker_times_ms);
1338 print_par_stats(2, "GC Worker End", _par_last_gc_worker_end_times_ms);
1339 } else {
1340 print_stats(1, "Ext Root Scanning", ext_root_scan_time);
1341 if (print_marking_info) {
1342 print_stats(1, "SATB Filtering", satb_filtering_time);
1343 }
1344 print_stats(1, "Update RS", update_rs_time);
1345 if (G1Log::finest()) {
1346 print_stats(2, "Processed Buffers", (int)update_rs_processed_buffers);
1347 }
1348 print_stats(1, "Scan RS", scan_rs_time);
1349 print_stats(1, "Object Copying", obj_copy_time);
1350 }
1351 print_stats(1, "Code Root Fixup", _cur_collection_code_root_fixup_time_ms);
1352 print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
1353 #ifndef PRODUCT
1354 print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
1355 print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
1356 print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
1357 print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
1358 if (_num_cc_clears > 0) {
1359 print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
1360 }
1361 #endif
1362 print_stats(1, "Other", other_time_ms);
1363 print_stats(2, "Choose CSet",
1364 (_recorded_young_cset_choice_time_ms +
1365 _recorded_non_young_cset_choice_time_ms));
1366 print_stats(2, "Ref Proc", _cur_ref_proc_time_ms);
1367 print_stats(2, "Ref Enq", _cur_ref_enq_time_ms);
1368 print_stats(2, "Free CSet",
1369 (_recorded_young_free_cset_time_ms +
1370 _recorded_non_young_free_cset_time_ms));
1371 }
1372
1373 bool new_in_marking_window = _in_marking_window;
1374 bool new_in_marking_window_im = false;
1375 if (during_initial_mark_pause()) {
1376 new_in_marking_window = true;
1377 new_in_marking_window_im = true;
1378 }
1379
1380 if (_last_young_gc) {
1381 // This is supposed to to be the "last young GC" before we start
1382 // doing mixed GCs. Here we decide whether to start mixed GCs or not.
1383
1384 if (!last_pause_included_initial_mark) {
1385 if (next_gc_should_be_mixed("start mixed GCs",
1386 "do not start mixed GCs")) {
1387 set_gcs_are_young(false);
1388 }
1389 } else {
1390 ergo_verbose0(ErgoMixedGCs,
1391 "do not start mixed GCs",
1392 ergo_format_reason("concurrent cycle is about to start"));
1393 }
1394 _last_young_gc = false;
1395 }
1396
1397 if (!_last_gc_was_young) {
1398 // This is a mixed GC. Here we decide whether to continue doing
1399 // mixed GCs or not.
1400
1401 if (!next_gc_should_be_mixed("continue mixed GCs",
1402 "do not continue mixed GCs")) {
1403 set_gcs_are_young(true);
1404 }
1405 }
1406
1407 _short_lived_surv_rate_group->start_adding_regions();
1408 // do that for any other surv rate groupsx
1409
1410 if (update_stats) {
1411 double pause_time_ms = elapsed_ms;
1412
1413 size_t diff = 0;
1414 if (_max_pending_cards >= _pending_cards) {
1415 diff = _max_pending_cards - _pending_cards;
1416 }
1417 _pending_card_diff_seq->add((double) diff);
1418
1419 double cost_per_card_ms = 0.0;
1420 if (_pending_cards > 0) {
1421 cost_per_card_ms = update_rs_time / (double) _pending_cards;
1422 _cost_per_card_ms_seq->add(cost_per_card_ms);
1423 }
1424
1425 size_t cards_scanned = _g1->cards_scanned();
1426
1427 double cost_per_entry_ms = 0.0;
1428 if (cards_scanned > 10) {
1429 cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
1430 if (_last_gc_was_young) {
1431 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1432 } else {
1433 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1434 }
1435 }
1436
1437 if (_max_rs_lengths > 0) {
1438 double cards_per_entry_ratio =
1439 (double) cards_scanned / (double) _max_rs_lengths;
1440 if (_last_gc_was_young) {
1441 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1442 } else {
1443 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1444 }
1445 }
1446
1447 // This is defensive. For a while _max_rs_lengths could get
1448 // smaller than _recorded_rs_lengths which was causing
1449 // rs_length_diff to get very large and mess up the RSet length
1450 // predictions. The reason was unsafe concurrent updates to the
1451 // _inc_cset_recorded_rs_lengths field which the code below guards
1452 // against (see CR 7118202). This bug has now been fixed (see CR
1453 // 7119027). However, I'm still worried that
1454 // _inc_cset_recorded_rs_lengths might still end up somewhat
1455 // inaccurate. The concurrent refinement thread calculates an
1456 // RSet's length concurrently with other CR threads updating it
1457 // which might cause it to calculate the length incorrectly (if,
1458 // say, it's in mid-coarsening). So I'll leave in the defensive
1459 // conditional below just in case.
1460 size_t rs_length_diff = 0;
1461 if (_max_rs_lengths > _recorded_rs_lengths) {
1462 rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1463 }
1464 _rs_length_diff_seq->add((double) rs_length_diff);
1465
1466 size_t copied_bytes = surviving_bytes;
1467 double cost_per_byte_ms = 0.0;
1468 if (copied_bytes > 0) {
1469 cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
1470 if (_in_marking_window) {
1471 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1472 } else {
1473 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1474 }
1475 }
1476
1477 double all_other_time_ms = pause_time_ms -
1478 (update_rs_time + scan_rs_time + obj_copy_time + termination_time);
1479
1480 double young_other_time_ms = 0.0;
1481 if (young_cset_region_length() > 0) {
1482 young_other_time_ms =
1483 _recorded_young_cset_choice_time_ms +
1484 _recorded_young_free_cset_time_ms;
1485 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1486 (double) young_cset_region_length());
1487 }
1488 double non_young_other_time_ms = 0.0;
1489 if (old_cset_region_length() > 0) {
1490 non_young_other_time_ms =
1491 _recorded_non_young_cset_choice_time_ms +
1492 _recorded_non_young_free_cset_time_ms;
1493
1494 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1495 (double) old_cset_region_length());
1496 }
1497
1498 double constant_other_time_ms = all_other_time_ms -
1499 (young_other_time_ms + non_young_other_time_ms);
1500 _constant_other_time_ms_seq->add(constant_other_time_ms);
1501
1502 double survival_ratio = 0.0;
1503 if (_bytes_in_collection_set_before_gc > 0) {
1504 survival_ratio = (double) _bytes_copied_during_gc /
1505 (double) _bytes_in_collection_set_before_gc;
1506 }
1507
1508 _pending_cards_seq->add((double) _pending_cards);
1509 _rs_lengths_seq->add((double) _max_rs_lengths);
1510 }
1511
1512 _in_marking_window = new_in_marking_window;
1513 _in_marking_window_im = new_in_marking_window_im;
1514 _free_regions_at_end_of_collection = _g1->free_regions();
1515 update_young_list_target_length();
1516
1517 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1518 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1519 adjust_concurrent_refinement(update_rs_time, update_rs_processed_buffers, update_rs_time_goal_ms);
1520
1521 _collectionSetChooser->verify();
1522 }
1523
1524 #define EXT_SIZE_FORMAT "%.1f%s"
1525 #define EXT_SIZE_PARAMS(bytes) \
1526 byte_size_in_proper_unit((double)(bytes)), \
1527 proper_unit_for_byte_size((bytes))
1528
1529 void G1CollectorPolicy::print_heap_transition() {
1530 if (G1Log::finer()) {
1531 YoungList* young_list = _g1->young_list();
1532 size_t eden_bytes = young_list->eden_used_bytes();
1533 size_t survivor_bytes = young_list->survivor_used_bytes();
1534 size_t used_before_gc = _cur_collection_pause_used_at_start_bytes;
1535 size_t used = _g1->used();
1536 size_t capacity = _g1->capacity();
1537 size_t eden_capacity =
1538 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_bytes;
1539
1540 gclog_or_tty->print_cr(
1541 " [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
1542 "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1543 "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
1544 EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
1545 EXT_SIZE_PARAMS(_eden_bytes_before_gc),
1546 EXT_SIZE_PARAMS(_prev_eden_capacity),
1547 EXT_SIZE_PARAMS(eden_bytes),
1548 EXT_SIZE_PARAMS(eden_capacity),
1549 EXT_SIZE_PARAMS(_survivor_bytes_before_gc),
1550 EXT_SIZE_PARAMS(survivor_bytes),
1551 EXT_SIZE_PARAMS(used_before_gc),
1552 EXT_SIZE_PARAMS(_capacity_before_gc),
1553 EXT_SIZE_PARAMS(used),
1554 EXT_SIZE_PARAMS(capacity));
1555
1556 _prev_eden_capacity = eden_capacity;
1557 } else if (G1Log::fine()) {
1558 _g1->print_size_transition(gclog_or_tty,
1559 _cur_collection_pause_used_at_start_bytes,
1560 _g1->used(), _g1->capacity());
1561 }
1562 }
1563
1564 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1565 double update_rs_processed_buffers,
1566 double goal_ms) {
1567 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1568 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1569
1570 if (G1UseAdaptiveConcRefinement) {
1571 const int k_gy = 3, k_gr = 6;
1572 const double inc_k = 1.1, dec_k = 0.9;
1573
1574 int g = cg1r->green_zone();
1575 if (update_rs_time > goal_ms) {
1576 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1577 } else {
1578 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1579 g = (int)MAX2(g * inc_k, g + 1.0);
1580 }
1581 }
1582 // Change the refinement threads params
1583 cg1r->set_green_zone(g);
1584 cg1r->set_yellow_zone(g * k_gy);
1585 cg1r->set_red_zone(g * k_gr);
1586 cg1r->reinitialize_threads();
1587
1588 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1589 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1590 cg1r->yellow_zone());
1591 // Change the barrier params
1592 dcqs.set_process_completed_threshold(processing_threshold);
1593 dcqs.set_max_completed_queue(cg1r->red_zone());
1594 }
1595
1596 int curr_queue_size = dcqs.completed_buffers_num();
1597 if (curr_queue_size >= cg1r->yellow_zone()) {
1598 dcqs.set_completed_queue_padding(curr_queue_size);
1599 } else {
1600 dcqs.set_completed_queue_padding(0);
1601 }
1602 dcqs.notify_if_necessary();
1603 }
1604
1605 double
1606 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1607 size_t rs_length = predict_rs_length_diff();
1608 size_t card_num;
1609 if (gcs_are_young()) {
1610 card_num = predict_young_card_num(rs_length);
1611 } else {
1612 card_num = predict_non_young_card_num(rs_length);
1613 }
1614 return predict_base_elapsed_time_ms(pending_cards, card_num);
1615 }
1616
1617 double
1618 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1619 size_t scanned_cards) {
1620 return
1621 predict_rs_update_time_ms(pending_cards) +
1622 predict_rs_scan_time_ms(scanned_cards) +
1623 predict_constant_other_time_ms();
1624 }
1625
1626 double
1627 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1628 bool young) {
1629 size_t rs_length = hr->rem_set()->occupied();
1630 size_t card_num;
1631 if (gcs_are_young()) {
1632 card_num = predict_young_card_num(rs_length);
1633 } else {
1634 card_num = predict_non_young_card_num(rs_length);
1635 }
1636 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1637
1638 double region_elapsed_time_ms =
1639 predict_rs_scan_time_ms(card_num) +
1640 predict_object_copy_time_ms(bytes_to_copy);
1641
1642 if (young)
1643 region_elapsed_time_ms += predict_young_other_time_ms(1);
1644 else
1645 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1646
1647 return region_elapsed_time_ms;
1648 }
1649
1650 size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1651 size_t bytes_to_copy;
1652 if (hr->is_marked())
1653 bytes_to_copy = hr->max_live_bytes();
1654 else {
1655 assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
1656 int age = hr->age_in_surv_rate_group();
1657 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1658 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1659 }
1660 return bytes_to_copy;
1661 }
1662
1663 void
1664 G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
1665 uint survivor_cset_region_length) {
1666 _eden_cset_region_length = eden_cset_region_length;
1667 _survivor_cset_region_length = survivor_cset_region_length;
1668 _old_cset_region_length = 0;
1669 }
1670
1671 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1672 _recorded_rs_lengths = rs_lengths;
1673 }
1674
1675 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1676 double elapsed_ms) {
1677 _recent_gc_times_ms->add(elapsed_ms);
1678 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1679 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1680 }
1681
1682 size_t G1CollectorPolicy::expansion_amount() {
1683 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
1684 double threshold = _gc_overhead_perc;
1685 if (recent_gc_overhead > threshold) {
1686 // We will double the existing space, or take
1687 // G1ExpandByPercentOfAvailable % of the available expansion
1688 // space, whichever is smaller, bounded below by a minimum
1689 // expansion (unless that's all that's left.)
1690 const size_t min_expand_bytes = 1*M;
1691 size_t reserved_bytes = _g1->max_capacity();
1692 size_t committed_bytes = _g1->capacity();
1693 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1694 size_t expand_bytes;
1695 size_t expand_bytes_via_pct =
1696 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1697 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1698 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1699 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1700
1701 ergo_verbose5(ErgoHeapSizing,
1702 "attempt heap expansion",
1703 ergo_format_reason("recent GC overhead higher than "
1704 "threshold after GC")
1705 ergo_format_perc("recent GC overhead")
1706 ergo_format_perc("threshold")
1707 ergo_format_byte("uncommitted")
1708 ergo_format_byte_perc("calculated expansion amount"),
1709 recent_gc_overhead, threshold,
1710 uncommitted_bytes,
1711 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
1712
1713 return expand_bytes;
1714 } else {
1715 return 0;
1716 }
1717 }
1718
1719 class CountCSClosure: public HeapRegionClosure {
1720 G1CollectorPolicy* _g1_policy;
1721 public:
1722 CountCSClosure(G1CollectorPolicy* g1_policy) :
1723 _g1_policy(g1_policy) {}
1724 bool doHeapRegion(HeapRegion* r) {
1725 _g1_policy->_bytes_in_collection_set_before_gc += r->used();
1726 return false;
1727 }
1728 };
1729
1730 void G1CollectorPolicy::count_CS_bytes_used() {
1731 CountCSClosure cs_closure(this);
1732 _g1->collection_set_iterate(&cs_closure);
1733 }
1734
1735 void G1CollectorPolicy::print_tracing_info() const {
1736 _trace_gen0_time_data.print();
1737 _trace_gen1_time_data.print();
1738 }
1739
1740 void G1CollectorPolicy::print_yg_surv_rate_info() const {
1741 #ifndef PRODUCT
1742 _short_lived_surv_rate_group->print_surv_rate_summary();
1743 // add this call for any other surv rate groups
1744 #endif // PRODUCT
1745 }
1746
1747 #ifndef PRODUCT
1748 // for debugging, bit of a hack...
1749 static char*
1750 region_num_to_mbs(int length) {
1751 static char buffer[64];
1752 double bytes = (double) (length * HeapRegion::GrainBytes);
1753 double mbs = bytes / (double) (1024 * 1024);
1754 sprintf(buffer, "%7.2lfMB", mbs);
1755 return buffer;
1756 }
1757 #endif // PRODUCT
1758
1759 uint G1CollectorPolicy::max_regions(int purpose) {
1760 switch (purpose) {
1761 case GCAllocForSurvived:
1762 return _max_survivor_regions;
1763 case GCAllocForTenured:
1764 return REGIONS_UNLIMITED;
1765 default:
1766 ShouldNotReachHere();
1767 return REGIONS_UNLIMITED;
1768 };
1769 }
1770
1771 void G1CollectorPolicy::update_max_gc_locker_expansion() {
1772 uint expansion_region_num = 0;
1773 if (GCLockerEdenExpansionPercent > 0) {
1774 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
1775 double expansion_region_num_d = perc * (double) _young_list_target_length;
1776 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
1777 // less than 1.0) we'll get 1.
1778 expansion_region_num = (uint) ceil(expansion_region_num_d);
1779 } else {
1780 assert(expansion_region_num == 0, "sanity");
1781 }
1782 _young_list_max_length = _young_list_target_length + expansion_region_num;
1783 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
1784 }
1785
1786 // Calculates survivor space parameters.
1787 void G1CollectorPolicy::update_survivors_policy() {
1788 double max_survivor_regions_d =
1789 (double) _young_list_target_length / (double) SurvivorRatio;
1790 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
1791 // smaller than 1.0) we'll get 1.
1792 _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
1793
1794 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
1795 HeapRegion::GrainWords * _max_survivor_regions);
1796 }
1797
1798 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
1799 GCCause::Cause gc_cause) {
1800 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1801 if (!during_cycle) {
1802 ergo_verbose1(ErgoConcCycles,
1803 "request concurrent cycle initiation",
1804 ergo_format_reason("requested by GC cause")
1805 ergo_format_str("GC cause"),
1806 GCCause::to_string(gc_cause));
1807 set_initiate_conc_mark_if_possible();
1808 return true;
1809 } else {
1810 ergo_verbose1(ErgoConcCycles,
1811 "do not request concurrent cycle initiation",
1812 ergo_format_reason("concurrent cycle already in progress")
1813 ergo_format_str("GC cause"),
1814 GCCause::to_string(gc_cause));
1815 return false;
1816 }
1817 }
1818
1819 void
1820 G1CollectorPolicy::decide_on_conc_mark_initiation() {
1821 // We are about to decide on whether this pause will be an
1822 // initial-mark pause.
1823
1824 // First, during_initial_mark_pause() should not be already set. We
1825 // will set it here if we have to. However, it should be cleared by
1826 // the end of the pause (it's only set for the duration of an
1827 // initial-mark pause).
1828 assert(!during_initial_mark_pause(), "pre-condition");
1829
1830 if (initiate_conc_mark_if_possible()) {
1831 // We had noticed on a previous pause that the heap occupancy has
1832 // gone over the initiating threshold and we should start a
1833 // concurrent marking cycle. So we might initiate one.
1834
1835 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
1836 if (!during_cycle) {
1837 // The concurrent marking thread is not "during a cycle", i.e.,
1838 // it has completed the last one. So we can go ahead and
1839 // initiate a new cycle.
1840
1841 set_during_initial_mark_pause();
1842 // We do not allow mixed GCs during marking.
1843 if (!gcs_are_young()) {
1844 set_gcs_are_young(true);
1845 ergo_verbose0(ErgoMixedGCs,
1846 "end mixed GCs",
1847 ergo_format_reason("concurrent cycle is about to start"));
1848 }
1849
1850 // And we can now clear initiate_conc_mark_if_possible() as
1851 // we've already acted on it.
1852 clear_initiate_conc_mark_if_possible();
1853
1854 ergo_verbose0(ErgoConcCycles,
1855 "initiate concurrent cycle",
1856 ergo_format_reason("concurrent cycle initiation requested"));
1857 } else {
1858 // The concurrent marking thread is still finishing up the
1859 // previous cycle. If we start one right now the two cycles
1860 // overlap. In particular, the concurrent marking thread might
1861 // be in the process of clearing the next marking bitmap (which
1862 // we will use for the next cycle if we start one). Starting a
1863 // cycle now will be bad given that parts of the marking
1864 // information might get cleared by the marking thread. And we
1865 // cannot wait for the marking thread to finish the cycle as it
1866 // periodically yields while clearing the next marking bitmap
1867 // and, if it's in a yield point, it's waiting for us to
1868 // finish. So, at this point we will not start a cycle and we'll
1869 // let the concurrent marking thread complete the last one.
1870 ergo_verbose0(ErgoConcCycles,
1871 "do not initiate concurrent cycle",
1872 ergo_format_reason("concurrent cycle already in progress"));
1873 }
1874 }
1875 }
1876
1877 class KnownGarbageClosure: public HeapRegionClosure {
1878 G1CollectedHeap* _g1h;
1879 CollectionSetChooser* _hrSorted;
1880
1881 public:
1882 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
1883 _g1h(G1CollectedHeap::heap()), _hrSorted(hrSorted) { }
1884
1885 bool doHeapRegion(HeapRegion* r) {
1886 // We only include humongous regions in collection
1887 // sets when concurrent mark shows that their contained object is
1888 // unreachable.
1889
1890 // Do we have any marking information for this region?
1891 if (r->is_marked()) {
1892 // We will skip any region that's currently used as an old GC
1893 // alloc region (we should not consider those for collection
1894 // before we fill them up).
1895 if (_hrSorted->should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1896 _hrSorted->add_region(r);
1897 }
1898 }
1899 return false;
1900 }
1901 };
1902
1903 class ParKnownGarbageHRClosure: public HeapRegionClosure {
1904 G1CollectedHeap* _g1h;
1905 CollectionSetChooser* _hrSorted;
1906 uint _marked_regions_added;
1907 size_t _reclaimable_bytes_added;
1908 uint _chunk_size;
1909 uint _cur_chunk_idx;
1910 uint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
1911
1912 void get_new_chunk() {
1913 _cur_chunk_idx = _hrSorted->claim_array_chunk(_chunk_size);
1914 _cur_chunk_end = _cur_chunk_idx + _chunk_size;
1915 }
1916 void add_region(HeapRegion* r) {
1917 if (_cur_chunk_idx == _cur_chunk_end) {
1918 get_new_chunk();
1919 }
1920 assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
1921 _hrSorted->set_region(_cur_chunk_idx, r);
1922 _marked_regions_added++;
1923 _reclaimable_bytes_added += r->reclaimable_bytes();
1924 _cur_chunk_idx++;
1925 }
1926
1927 public:
1928 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
1929 uint chunk_size) :
1930 _g1h(G1CollectedHeap::heap()),
1931 _hrSorted(hrSorted), _chunk_size(chunk_size),
1932 _marked_regions_added(0), _reclaimable_bytes_added(0),
1933 _cur_chunk_idx(0), _cur_chunk_end(0) { }
1934
1935 bool doHeapRegion(HeapRegion* r) {
1936 // Do we have any marking information for this region?
1937 if (r->is_marked()) {
1938 // We will skip any region that's currently used as an old GC
1939 // alloc region (we should not consider those for collection
1940 // before we fill them up).
1941 if (_hrSorted->should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
1942 add_region(r);
1943 }
1944 }
1945 return false;
1946 }
1947 uint marked_regions_added() { return _marked_regions_added; }
1948 size_t reclaimable_bytes_added() { return _reclaimable_bytes_added; }
1949 };
1950
1951 class ParKnownGarbageTask: public AbstractGangTask {
1952 CollectionSetChooser* _hrSorted;
1953 uint _chunk_size;
1954 G1CollectedHeap* _g1;
1955 public:
1956 ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size) :
1957 AbstractGangTask("ParKnownGarbageTask"),
1958 _hrSorted(hrSorted), _chunk_size(chunk_size),
1959 _g1(G1CollectedHeap::heap()) { }
1960
1961 void work(uint worker_id) {
1962 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
1963
1964 // Back to zero for the claim value.
1965 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, worker_id,
1966 _g1->workers()->active_workers(),
1967 HeapRegion::InitialClaimValue);
1968 uint regions_added = parKnownGarbageCl.marked_regions_added();
1969 size_t reclaimable_bytes_added =
1970 parKnownGarbageCl.reclaimable_bytes_added();
1971 _hrSorted->update_totals(regions_added, reclaimable_bytes_added);
1972 }
1973 };
1974
1975 void
1976 G1CollectorPolicy::record_concurrent_mark_cleanup_end(int no_of_gc_threads) {
1977 _collectionSetChooser->clear();
1978
1979 uint region_num = _g1->n_regions();
1980 if (G1CollectedHeap::use_parallel_gc_threads()) {
1981 const uint OverpartitionFactor = 4;
1982 uint WorkUnit;
1983 // The use of MinChunkSize = 8 in the original code
1984 // causes some assertion failures when the total number of
1985 // region is less than 8. The code here tries to fix that.
1986 // Should the original code also be fixed?
1987 if (no_of_gc_threads > 0) {
1988 const uint MinWorkUnit = MAX2(region_num / no_of_gc_threads, 1U);
1989 WorkUnit = MAX2(region_num / (no_of_gc_threads * OverpartitionFactor),
1990 MinWorkUnit);
1991 } else {
1992 assert(no_of_gc_threads > 0,
1993 "The active gc workers should be greater than 0");
1994 // In a product build do something reasonable to avoid a crash.
1995 const uint MinWorkUnit = MAX2(region_num / (uint) ParallelGCThreads, 1U);
1996 WorkUnit =
1997 MAX2(region_num / (uint) (ParallelGCThreads * OverpartitionFactor),
1998 MinWorkUnit);
1999 }
2000 _collectionSetChooser->prepare_for_par_region_addition(_g1->n_regions(),
2001 WorkUnit);
2002 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
2003 (int) WorkUnit);
2004 _g1->workers()->run_task(&parKnownGarbageTask);
2005
2006 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
2007 "sanity check");
2008 } else {
2009 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
2010 _g1->heap_region_iterate(&knownGarbagecl);
2011 }
2012
2013 _collectionSetChooser->sort_regions();
2014
2015 double end_sec = os::elapsedTime();
2016 double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
2017 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
2018 _cur_mark_stop_world_time_ms += elapsed_time_ms;
2019 _prev_collection_pause_end_ms += elapsed_time_ms;
2020 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true);
2021 }
2022
2023 // Add the heap region at the head of the non-incremental collection set
2024 void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
2025 assert(_inc_cset_build_state == Active, "Precondition");
2026 assert(!hr->is_young(), "non-incremental add of young region");
2027
2028 assert(!hr->in_collection_set(), "should not already be in the CSet");
2029 hr->set_in_collection_set(true);
2030 hr->set_next_in_collection_set(_collection_set);
2031 _collection_set = hr;
2032 _collection_set_bytes_used_before += hr->used();
2033 _g1->register_region_with_in_cset_fast_test(hr);
2034 size_t rs_length = hr->rem_set()->occupied();
2035 _recorded_rs_lengths += rs_length;
2036 _old_cset_region_length += 1;
2037 }
2038
2039 // Initialize the per-collection-set information
2040 void G1CollectorPolicy::start_incremental_cset_building() {
2041 assert(_inc_cset_build_state == Inactive, "Precondition");
2042
2043 _inc_cset_head = NULL;
2044 _inc_cset_tail = NULL;
2045 _inc_cset_bytes_used_before = 0;
2046
2047 _inc_cset_max_finger = 0;
2048 _inc_cset_recorded_rs_lengths = 0;
2049 _inc_cset_recorded_rs_lengths_diffs = 0;
2050 _inc_cset_predicted_elapsed_time_ms = 0.0;
2051 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
2052 _inc_cset_build_state = Active;
2053 }
2054
2055 void G1CollectorPolicy::finalize_incremental_cset_building() {
2056 assert(_inc_cset_build_state == Active, "Precondition");
2057 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
2058
2059 // The two "main" fields, _inc_cset_recorded_rs_lengths and
2060 // _inc_cset_predicted_elapsed_time_ms, are updated by the thread
2061 // that adds a new region to the CSet. Further updates by the
2062 // concurrent refinement thread that samples the young RSet lengths
2063 // are accumulated in the *_diffs fields. Here we add the diffs to
2064 // the "main" fields.
2065
2066 if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
2067 _inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
2068 } else {
2069 // This is defensive. The diff should in theory be always positive
2070 // as RSets can only grow between GCs. However, given that we
2071 // sample their size concurrently with other threads updating them
2072 // it's possible that we might get the wrong size back, which
2073 // could make the calculations somewhat inaccurate.
2074 size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
2075 if (_inc_cset_recorded_rs_lengths >= diffs) {
2076 _inc_cset_recorded_rs_lengths -= diffs;
2077 } else {
2078 _inc_cset_recorded_rs_lengths = 0;
2079 }
2080 }
2081 _inc_cset_predicted_elapsed_time_ms +=
2082 _inc_cset_predicted_elapsed_time_ms_diffs;
2083
2084 _inc_cset_recorded_rs_lengths_diffs = 0;
2085 _inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
2086 }
2087
2088 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
2089 // This routine is used when:
2090 // * adding survivor regions to the incremental cset at the end of an
2091 // evacuation pause,
2092 // * adding the current allocation region to the incremental cset
2093 // when it is retired, and
2094 // * updating existing policy information for a region in the
2095 // incremental cset via young list RSet sampling.
2096 // Therefore this routine may be called at a safepoint by the
2097 // VM thread, or in-between safepoints by mutator threads (when
2098 // retiring the current allocation region) or a concurrent
2099 // refine thread (RSet sampling).
2100
2101 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
2102 size_t used_bytes = hr->used();
2103 _inc_cset_recorded_rs_lengths += rs_length;
2104 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
2105 _inc_cset_bytes_used_before += used_bytes;
2106
2107 // Cache the values we have added to the aggregated informtion
2108 // in the heap region in case we have to remove this region from
2109 // the incremental collection set, or it is updated by the
2110 // rset sampling code
2111 hr->set_recorded_rs_length(rs_length);
2112 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
2113 }
2114
2115 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
2116 size_t new_rs_length) {
2117 // Update the CSet information that is dependent on the new RS length
2118 assert(hr->is_young(), "Precondition");
2119 assert(!SafepointSynchronize::is_at_safepoint(),
2120 "should not be at a safepoint");
2121
2122 // We could have updated _inc_cset_recorded_rs_lengths and
2123 // _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
2124 // that atomically, as this code is executed by a concurrent
2125 // refinement thread, potentially concurrently with a mutator thread
2126 // allocating a new region and also updating the same fields. To
2127 // avoid the atomic operations we accumulate these updates on two
2128 // separate fields (*_diffs) and we'll just add them to the "main"
2129 // fields at the start of a GC.
2130
2131 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
2132 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
2133 _inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
2134
2135 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
2136 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
2137 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
2138 _inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
2139
2140 hr->set_recorded_rs_length(new_rs_length);
2141 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
2142 }
2143
2144 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
2145 assert(hr->is_young(), "invariant");
2146 assert(hr->young_index_in_cset() > -1, "should have already been set");
2147 assert(_inc_cset_build_state == Active, "Precondition");
2148
2149 // We need to clear and set the cached recorded/cached collection set
2150 // information in the heap region here (before the region gets added
2151 // to the collection set). An individual heap region's cached values
2152 // are calculated, aggregated with the policy collection set info,
2153 // and cached in the heap region here (initially) and (subsequently)
2154 // by the Young List sampling code.
2155
2156 size_t rs_length = hr->rem_set()->occupied();
2157 add_to_incremental_cset_info(hr, rs_length);
2158
2159 HeapWord* hr_end = hr->end();
2160 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
2161
2162 assert(!hr->in_collection_set(), "invariant");
2163 hr->set_in_collection_set(true);
2164 assert( hr->next_in_collection_set() == NULL, "invariant");
2165
2166 _g1->register_region_with_in_cset_fast_test(hr);
2167 }
2168
2169 // Add the region at the RHS of the incremental cset
2170 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
2171 // We should only ever be appending survivors at the end of a pause
2172 assert( hr->is_survivor(), "Logic");
2173
2174 // Do the 'common' stuff
2175 add_region_to_incremental_cset_common(hr);
2176
2177 // Now add the region at the right hand side
2178 if (_inc_cset_tail == NULL) {
2179 assert(_inc_cset_head == NULL, "invariant");
2180 _inc_cset_head = hr;
2181 } else {
2182 _inc_cset_tail->set_next_in_collection_set(hr);
2183 }
2184 _inc_cset_tail = hr;
2185 }
2186
2187 // Add the region to the LHS of the incremental cset
2188 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
2189 // Survivors should be added to the RHS at the end of a pause
2190 assert(!hr->is_survivor(), "Logic");
2191
2192 // Do the 'common' stuff
2193 add_region_to_incremental_cset_common(hr);
2194
2195 // Add the region at the left hand side
2196 hr->set_next_in_collection_set(_inc_cset_head);
2197 if (_inc_cset_head == NULL) {
2198 assert(_inc_cset_tail == NULL, "Invariant");
2199 _inc_cset_tail = hr;
2200 }
2201 _inc_cset_head = hr;
2202 }
2203
2204 #ifndef PRODUCT
2205 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
2206 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
2207
2208 st->print_cr("\nCollection_set:");
2209 HeapRegion* csr = list_head;
2210 while (csr != NULL) {
2211 HeapRegion* next = csr->next_in_collection_set();
2212 assert(csr->in_collection_set(), "bad CS");
2213 st->print_cr(" "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
2214 HR_FORMAT_PARAMS(csr),
2215 csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(),
2216 csr->age_in_surv_rate_group_cond());
2217 csr = next;
2218 }
2219 }
2220 #endif // !PRODUCT
2221
2222 bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
2223 const char* false_action_str) {
2224 CollectionSetChooser* cset_chooser = _collectionSetChooser;
2225 if (cset_chooser->is_empty()) {
2226 ergo_verbose0(ErgoMixedGCs,
2227 false_action_str,
2228 ergo_format_reason("candidate old regions not available"));
2229 return false;
2230 }
2231 size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
2232 size_t capacity_bytes = _g1->capacity();
2233 double perc = (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
2234 double threshold = (double) G1HeapWastePercent;
2235 if (perc < threshold) {
2236 ergo_verbose4(ErgoMixedGCs,
2237 false_action_str,
2238 ergo_format_reason("reclaimable percentage lower than threshold")
2239 ergo_format_region("candidate old regions")
2240 ergo_format_byte_perc("reclaimable")
2241 ergo_format_perc("threshold"),
2242 cset_chooser->remaining_regions(),
2243 reclaimable_bytes, perc, threshold);
2244 return false;
2245 }
2246
2247 ergo_verbose4(ErgoMixedGCs,
2248 true_action_str,
2249 ergo_format_reason("candidate old regions available")
2250 ergo_format_region("candidate old regions")
2251 ergo_format_byte_perc("reclaimable")
2252 ergo_format_perc("threshold"),
2253 cset_chooser->remaining_regions(),
2254 reclaimable_bytes, perc, threshold);
2255 return true;
2256 }
2257
2258 void G1CollectorPolicy::finalize_cset(double target_pause_time_ms) {
2259 // Set this here - in case we're not doing young collections.
2260 double non_young_start_time_sec = os::elapsedTime();
2261
2262 YoungList* young_list = _g1->young_list();
2263 finalize_incremental_cset_building();
2264
2265 guarantee(target_pause_time_ms > 0.0,
2266 err_msg("target_pause_time_ms = %1.6lf should be positive",
2267 target_pause_time_ms));
2268 guarantee(_collection_set == NULL, "Precondition");
2269
2270 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2271 double predicted_pause_time_ms = base_time_ms;
2272 double time_remaining_ms = target_pause_time_ms - base_time_ms;
2273
2274 ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
2275 "start choosing CSet",
2276 ergo_format_ms("predicted base time")
2277 ergo_format_ms("remaining time")
2278 ergo_format_ms("target pause time"),
2279 base_time_ms, time_remaining_ms, target_pause_time_ms);
2280
2281 HeapRegion* hr;
2282 double young_start_time_sec = os::elapsedTime();
2283
2284 _collection_set_bytes_used_before = 0;
2285 _last_gc_was_young = gcs_are_young() ? true : false;
2286
2287 _trace_gen0_time_data.increment_collection_count(!_last_gc_was_young);
2288 if (_last_gc_was_young) {
2289 ++_young_pause_num;
2290 } else {
2291 ++_mixed_pause_num;
2292 }
2293
2294 // The young list is laid with the survivor regions from the previous
2295 // pause are appended to the RHS of the young list, i.e.
2296 // [Newly Young Regions ++ Survivors from last pause].
2297
2298 uint survivor_region_length = young_list->survivor_length();
2299 uint eden_region_length = young_list->length() - survivor_region_length;
2300 init_cset_region_lengths(eden_region_length, survivor_region_length);
2301 hr = young_list->first_survivor_region();
2302 while (hr != NULL) {
2303 assert(hr->is_survivor(), "badly formed young list");
2304 hr->set_young();
2305 hr = hr->get_next_young_region();
2306 }
2307
2308 // Clear the fields that point to the survivor list - they are all young now.
2309 young_list->clear_survivors();
2310
2311 _collection_set = _inc_cset_head;
2312 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2313 time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms;
2314 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
2315
2316 ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
2317 "add young regions to CSet",
2318 ergo_format_region("eden")
2319 ergo_format_region("survivors")
2320 ergo_format_ms("predicted young region time"),
2321 eden_region_length, survivor_region_length,
2322 _inc_cset_predicted_elapsed_time_ms);
2323
2324 // The number of recorded young regions is the incremental
2325 // collection set's current size
2326 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2327
2328 double young_end_time_sec = os::elapsedTime();
2329 _recorded_young_cset_choice_time_ms =
2330 (young_end_time_sec - young_start_time_sec) * 1000.0;
2331
2332 // We are doing young collections so reset this.
2333 non_young_start_time_sec = young_end_time_sec;
2334
2335 if (!gcs_are_young()) {
2336 CollectionSetChooser* cset_chooser = _collectionSetChooser;
2337 cset_chooser->verify();
2338 const uint min_old_cset_length = cset_chooser->calc_min_old_cset_length();
2339 const uint max_old_cset_length = cset_chooser->calc_max_old_cset_length();
2340
2341 uint expensive_region_num = 0;
2342 bool check_time_remaining = adaptive_young_list_length();
2343 HeapRegion* hr = cset_chooser->peek();
2344 while (hr != NULL) {
2345 if (old_cset_region_length() >= max_old_cset_length) {
2346 // Added maximum number of old regions to the CSet.
2347 ergo_verbose2(ErgoCSetConstruction,
2348 "finish adding old regions to CSet",
2349 ergo_format_reason("old CSet region num reached max")
2350 ergo_format_region("old")
2351 ergo_format_region("max"),
2352 old_cset_region_length(), max_old_cset_length);
2353 break;
2354 }
2355
2356 double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
2357 if (check_time_remaining) {
2358 if (predicted_time_ms > time_remaining_ms) {
2359 // Too expensive for the current CSet.
2360
2361 if (old_cset_region_length() >= min_old_cset_length) {
2362 // We have added the minimum number of old regions to the CSet,
2363 // we are done with this CSet.
2364 ergo_verbose4(ErgoCSetConstruction,
2365 "finish adding old regions to CSet",
2366 ergo_format_reason("predicted time is too high")
2367 ergo_format_ms("predicted time")
2368 ergo_format_ms("remaining time")
2369 ergo_format_region("old")
2370 ergo_format_region("min"),
2371 predicted_time_ms, time_remaining_ms,
2372 old_cset_region_length(), min_old_cset_length);
2373 break;
2374 }
2375
2376 // We'll add it anyway given that we haven't reached the
2377 // minimum number of old regions.
2378 expensive_region_num += 1;
2379 }
2380 } else {
2381 if (old_cset_region_length() >= min_old_cset_length) {
2382 // In the non-auto-tuning case, we'll finish adding regions
2383 // to the CSet if we reach the minimum.
2384 ergo_verbose2(ErgoCSetConstruction,
2385 "finish adding old regions to CSet",
2386 ergo_format_reason("old CSet region num reached min")
2387 ergo_format_region("old")
2388 ergo_format_region("min"),
2389 old_cset_region_length(), min_old_cset_length);
2390 break;
2391 }
2392 }
2393
2394 // We will add this region to the CSet.
2395 time_remaining_ms -= predicted_time_ms;
2396 predicted_pause_time_ms += predicted_time_ms;
2397 cset_chooser->remove_and_move_to_next(hr);
2398 _g1->old_set_remove(hr);
2399 add_old_region_to_cset(hr);
2400
2401 hr = cset_chooser->peek();
2402 }
2403 if (hr == NULL) {
2404 ergo_verbose0(ErgoCSetConstruction,
2405 "finish adding old regions to CSet",
2406 ergo_format_reason("candidate old regions not available"));
2407 }
2408
2409 if (expensive_region_num > 0) {
2410 // We print the information once here at the end, predicated on
2411 // whether we added any apparently expensive regions or not, to
2412 // avoid generating output per region.
2413 ergo_verbose4(ErgoCSetConstruction,
2414 "added expensive regions to CSet",
2415 ergo_format_reason("old CSet region num not reached min")
2416 ergo_format_region("old")
2417 ergo_format_region("expensive")
2418 ergo_format_region("min")
2419 ergo_format_ms("remaining time"),
2420 old_cset_region_length(),
2421 expensive_region_num,
2422 min_old_cset_length,
2423 time_remaining_ms);
2424 }
2425
2426 cset_chooser->verify();
2427 }
2428
2429 stop_incremental_cset_building();
2430
2431 count_CS_bytes_used();
2432
2433 ergo_verbose5(ErgoCSetConstruction,
2434 "finish choosing CSet",
2435 ergo_format_region("eden")
2436 ergo_format_region("survivors")
2437 ergo_format_region("old")
2438 ergo_format_ms("predicted pause time")
2439 ergo_format_ms("target pause time"),
2440 eden_region_length, survivor_region_length,
2441 old_cset_region_length(),
2442 predicted_pause_time_ms, target_pause_time_ms);
2443
2444 double non_young_end_time_sec = os::elapsedTime();
2445 _recorded_non_young_cset_choice_time_ms =
2446 (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
2447 }
2448
2449 void TraceGen0TimeData::record_start_collection(double time_to_stop_the_world_ms) {
2450 if(TraceGen0Time) {
2451 _all_stop_world_times_ms.add(time_to_stop_the_world_ms);
2452 }
2453 }
2454
2455 void TraceGen0TimeData::record_yield_time(double yield_time_ms) {
2456 if(TraceGen0Time) {
2457 _all_yield_times_ms.add(yield_time_ms);
2458 }
2459 }
2460
2461 void TraceGen0TimeData::record_end_collection(
2462 double total_ms,
2463 double other_ms,
2464 double root_region_scan_wait_ms,
2465 double parallel_ms,
2466 double ext_root_scan_ms,
2467 double satb_filtering_ms,
2468 double update_rs_ms,
2469 double scan_rs_ms,
2470 double obj_copy_ms,
2471 double termination_ms,
2472 double parallel_other_ms,
2473 double clear_ct_ms)
2474 {
2475 if(TraceGen0Time) {
2476 _total.add(total_ms);
2477 _other.add(other_ms);
2478 _root_region_scan_wait.add(root_region_scan_wait_ms);
2479 _parallel.add(parallel_ms);
2480 _ext_root_scan.add(ext_root_scan_ms);
2481 _satb_filtering.add(satb_filtering_ms);
2482 _update_rs.add(update_rs_ms);
2483 _scan_rs.add(scan_rs_ms);
2484 _obj_copy.add(obj_copy_ms);
2485 _termination.add(termination_ms);
2486 _parallel_other.add(parallel_other_ms);
2487 _clear_ct.add(clear_ct_ms);
2488 }
2489 }
2490
2491 void TraceGen0TimeData::increment_collection_count(bool mixed) {
2492 if(TraceGen0Time) {
2493 if (mixed) {
2494 ++_mixed_pause_num;
2495 } else {
2496 ++_young_pause_num;
2497 }
2498 }
2499 }
2500
2501 void TraceGen0TimeData::print_summary(int level,
2502 const char* str,
2503 const NumberSeq* seq) const {
2504 double sum = seq->sum();
2505 LineBuffer(level + 1).append_and_print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
2506 str, sum / 1000.0, seq->avg());
2507 }
2508
2509 void TraceGen0TimeData::print_summary_sd(int level,
2510 const char* str,
2511 const NumberSeq* seq) const {
2512 print_summary(level, str, seq);
2513 LineBuffer(level + 6).append_and_print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2514 seq->num(), seq->sd(), seq->maximum());
2515 }
2516
2517 void TraceGen0TimeData::print() const {
2518 if (!TraceGen0Time) {
2519 return;
2520 }
2521
2522 gclog_or_tty->print_cr("ALL PAUSES");
2523 print_summary_sd(0, "Total", &_total);
2524 gclog_or_tty->print_cr("");
2525 gclog_or_tty->print_cr("");
2526 gclog_or_tty->print_cr(" Young GC Pauses: %8d", _young_pause_num);
2527 gclog_or_tty->print_cr(" Mixed GC Pauses: %8d", _mixed_pause_num);
2528 gclog_or_tty->print_cr("");
2529
2530 gclog_or_tty->print_cr("EVACUATION PAUSES");
2531
2532 if (_young_pause_num == 0 && _mixed_pause_num == 0) {
2533 gclog_or_tty->print_cr("none");
2534 } else {
2535 print_summary_sd(0, "Evacuation Pauses", &_total);
2536 print_summary(1, "Root Region Scan Wait", &_root_region_scan_wait);
2537 print_summary(1, "Parallel Time", &_parallel);
2538 print_summary(2, "Ext Root Scanning", &_ext_root_scan);
2539 print_summary(2, "SATB Filtering", &_satb_filtering);
2540 print_summary(2, "Update RS", &_update_rs);
2541 print_summary(2, "Scan RS", &_scan_rs);
2542 print_summary(2, "Object Copy", &_obj_copy);
2543 print_summary(2, "Termination", &_termination);
2544 print_summary(2, "Parallel Other", &_parallel_other);
2545 print_summary(1, "Clear CT", &_clear_ct);
2546 print_summary(1, "Other", &_other);
2547 }
2548 gclog_or_tty->print_cr("");
2549
2550 gclog_or_tty->print_cr("MISC");
2551 print_summary_sd(0, "Stop World", &_all_stop_world_times_ms);
2552 print_summary_sd(0, "Yields", &_all_yield_times_ms);
2553 }
2554
2555 void TraceGen1TimeData::record_full_collection(double full_gc_time_ms) {
2556 if (TraceGen1Time) {
2557 _all_full_gc_times.add(full_gc_time_ms);
2558 }
2559 }
2560
2561 void TraceGen1TimeData::print() const {
2562 if (!TraceGen1Time) {
2563 return;
2564 }
2565
2566 if (_all_full_gc_times.num() > 0) {
2567 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2568 _all_full_gc_times.num(),
2569 _all_full_gc_times.sum() / 1000.0);
2570 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
2571 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2572 _all_full_gc_times.sd(),
2573 _all_full_gc_times.maximum());
2574 }
2575 }