1 /*
2 * Copyright (c) 2001, 2011, 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/heapRegionRemSet.hpp"
32 #include "gc_implementation/shared/gcPolicyCounters.hpp"
33 #include "runtime/arguments.hpp"
34 #include "runtime/java.hpp"
35 #include "runtime/mutexLocker.hpp"
36 #include "utilities/debug.hpp"
37
38 #define PREDICTIONS_VERBOSE 0
39
40 // <NEW PREDICTION>
41
42 // Different defaults for different number of GC threads
43 // They were chosen by running GCOld and SPECjbb on debris with different
44 // numbers of GC threads and choosing them based on the results
45
46 // all the same
47 static double rs_length_diff_defaults[] = {
48 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
49 };
50
51 static double cost_per_card_ms_defaults[] = {
52 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
53 };
54
55 // all the same
56 static double fully_young_cards_per_entry_ratio_defaults[] = {
57 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
58 };
59
60 static double cost_per_entry_ms_defaults[] = {
61 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
62 };
63
64 static double cost_per_byte_ms_defaults[] = {
65 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
66 };
67
68 // these should be pretty consistent
69 static double constant_other_time_ms_defaults[] = {
70 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
71 };
72
73
74 static double young_other_cost_per_region_ms_defaults[] = {
75 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
76 };
77
78 static double non_young_other_cost_per_region_ms_defaults[] = {
79 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
80 };
81
82 // </NEW PREDICTION>
83
84 // Help class for avoiding interleaved logging
85 class LineBuffer: public StackObj {
86
87 private:
88 static const int BUFFER_LEN = 1024;
89 static const int INDENT_CHARS = 3;
90 char _buffer[BUFFER_LEN];
91 int _indent_level;
92 int _cur;
93
94 void vappend(const char* format, va_list ap) {
95 int res = vsnprintf(&_buffer[_cur], BUFFER_LEN - _cur, format, ap);
96 if (res != -1) {
97 _cur += res;
98 } else {
99 DEBUG_ONLY(warning("buffer too small in LineBuffer");)
100 _buffer[BUFFER_LEN -1] = 0;
101 _cur = BUFFER_LEN; // vsnprintf above should not add to _buffer if we are called again
102 }
103 }
104
105 public:
106 explicit LineBuffer(int indent_level): _indent_level(indent_level), _cur(0) {
107 for (; (_cur < BUFFER_LEN && _cur < (_indent_level * INDENT_CHARS)); _cur++) {
108 _buffer[_cur] = ' ';
109 }
110 }
111
112 #ifndef PRODUCT
113 ~LineBuffer() {
114 assert(_cur == _indent_level * INDENT_CHARS, "pending data in buffer - append_and_print_cr() not called?");
115 }
116 #endif
117
118 void append(const char* format, ...) {
119 va_list ap;
120 va_start(ap, format);
121 vappend(format, ap);
122 va_end(ap);
123 }
124
125 void append_and_print_cr(const char* format, ...) {
126 va_list ap;
127 va_start(ap, format);
128 vappend(format, ap);
129 va_end(ap);
130 gclog_or_tty->print_cr("%s", _buffer);
131 _cur = _indent_level * INDENT_CHARS;
132 }
133 };
134
135 G1CollectorPolicy::G1CollectorPolicy() :
136 _parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads()
137 ? ParallelGCThreads : 1),
138
139
140 _n_pauses(0),
141 _recent_CH_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
142 _recent_G1_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
143 _recent_evac_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
144 _recent_pause_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
145 _recent_rs_sizes(new TruncatedSeq(NumPrevPausesForHeuristics)),
146 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
147 _all_pause_times_ms(new NumberSeq()),
148 _stop_world_start(0.0),
149 _all_stop_world_times_ms(new NumberSeq()),
150 _all_yield_times_ms(new NumberSeq()),
151
152 _all_mod_union_times_ms(new NumberSeq()),
153
154 _summary(new Summary()),
155
156 #ifndef PRODUCT
157 _cur_clear_ct_time_ms(0.0),
158 _min_clear_cc_time_ms(-1.0),
159 _max_clear_cc_time_ms(-1.0),
160 _cur_clear_cc_time_ms(0.0),
161 _cum_clear_cc_time_ms(0.0),
162 _num_cc_clears(0L),
163 #endif
164
165 _region_num_young(0),
166 _region_num_tenured(0),
167 _prev_region_num_young(0),
168 _prev_region_num_tenured(0),
169
170 _aux_num(10),
171 _all_aux_times_ms(new NumberSeq[_aux_num]),
172 _cur_aux_start_times_ms(new double[_aux_num]),
173 _cur_aux_times_ms(new double[_aux_num]),
174 _cur_aux_times_set(new bool[_aux_num]),
175
176 _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
177 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
178 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
179
180 // <NEW PREDICTION>
181
182 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
183 _prev_collection_pause_end_ms(0.0),
184 _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
185 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
186 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
187 _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
188 _partially_young_cards_per_entry_ratio_seq(
189 new TruncatedSeq(TruncatedSeqLength)),
190 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
191 _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
192 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
193 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
194 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
195 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
196 _non_young_other_cost_per_region_ms_seq(
197 new TruncatedSeq(TruncatedSeqLength)),
198
199 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
200 _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
201 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
202
203 _pause_time_target_ms((double) MaxGCPauseMillis),
204
205 // </NEW PREDICTION>
206
207 _in_young_gc_mode(false),
208 _full_young_gcs(true),
209 _full_young_pause_num(0),
210 _partial_young_pause_num(0),
211
212 _during_marking(false),
213 _in_marking_window(false),
214 _in_marking_window_im(false),
215
216 _known_garbage_ratio(0.0),
217 _known_garbage_bytes(0),
218
219 _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
220
221 _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
222
223 _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
224 _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
225
226 _recent_avg_pause_time_ratio(0.0),
227 _num_markings(0),
228 _n_marks(0),
229 _n_pauses_at_mark_end(0),
230
231 _all_full_gc_times_ms(new NumberSeq()),
232
233 // G1PausesBtwnConcMark defaults to -1
234 // so the hack is to do the cast QQQ FIXME
235 _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
236 _n_marks_since_last_pause(0),
237 _initiate_conc_mark_if_possible(false),
238 _during_initial_mark_pause(false),
239 _should_revert_to_full_young_gcs(false),
240 _last_full_young_gc(false),
241
242 _eden_bytes_before_gc(0),
243 _survivor_bytes_before_gc(0),
244 _capacity_before_gc(0),
245
246 _prev_collection_pause_used_at_end_bytes(0),
247
248 _collection_set(NULL),
249 _collection_set_size(0),
250 _collection_set_bytes_used_before(0),
251
252 // Incremental CSet attributes
253 _inc_cset_build_state(Inactive),
254 _inc_cset_head(NULL),
255 _inc_cset_tail(NULL),
256 _inc_cset_size(0),
257 _inc_cset_young_index(0),
258 _inc_cset_bytes_used_before(0),
259 _inc_cset_max_finger(NULL),
260 _inc_cset_recorded_young_bytes(0),
261 _inc_cset_recorded_rs_lengths(0),
262 _inc_cset_predicted_elapsed_time_ms(0.0),
263 _inc_cset_predicted_bytes_to_copy(0),
264
265 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
266 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
267 #endif // _MSC_VER
268
269 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
270 G1YoungSurvRateNumRegionsSummary)),
271 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
272 G1YoungSurvRateNumRegionsSummary)),
273 // add here any more surv rate groups
274 _recorded_survivor_regions(0),
275 _recorded_survivor_head(NULL),
276 _recorded_survivor_tail(NULL),
277 _survivors_age_table(true),
278
279 _gc_overhead_perc(0.0)
280
281 {
282 // Set up the region size and associated fields. Given that the
283 // policy is created before the heap, we have to set this up here,
284 // so it's done as soon as possible.
285 HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
286 HeapRegionRemSet::setup_remset_size();
287
288 // Verify PLAB sizes
289 const uint region_size = HeapRegion::GrainWords;
290 if (YoungPLABSize > region_size || OldPLABSize > region_size) {
291 char buffer[128];
292 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most %u",
293 OldPLABSize > region_size ? "Old" : "Young", region_size);
294 vm_exit_during_initialization(buffer);
295 }
296
297 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
298 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
299
300 _par_last_gc_worker_start_times_ms = new double[_parallel_gc_threads];
301 _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
302 _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
303
304 _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
305 _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
306
307 _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
308
309 _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
310
311 _par_last_termination_times_ms = new double[_parallel_gc_threads];
312 _par_last_termination_attempts = new double[_parallel_gc_threads];
313 _par_last_gc_worker_end_times_ms = new double[_parallel_gc_threads];
314 _par_last_gc_worker_times_ms = new double[_parallel_gc_threads];
315
316 // start conservatively
317 _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
318
319 // <NEW PREDICTION>
320
321 int index;
322 if (ParallelGCThreads == 0)
323 index = 0;
324 else if (ParallelGCThreads > 8)
325 index = 7;
326 else
327 index = ParallelGCThreads - 1;
328
329 _pending_card_diff_seq->add(0.0);
330 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
331 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
332 _fully_young_cards_per_entry_ratio_seq->add(
333 fully_young_cards_per_entry_ratio_defaults[index]);
334 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
335 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
336 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
337 _young_other_cost_per_region_ms_seq->add(
338 young_other_cost_per_region_ms_defaults[index]);
339 _non_young_other_cost_per_region_ms_seq->add(
340 non_young_other_cost_per_region_ms_defaults[index]);
341
342 // </NEW PREDICTION>
343
344 // Below, we might need to calculate the pause time target based on
345 // the pause interval. When we do so we are going to give G1 maximum
346 // flexibility and allow it to do pauses when it needs to. So, we'll
347 // arrange that the pause interval to be pause time target + 1 to
348 // ensure that a) the pause time target is maximized with respect to
349 // the pause interval and b) we maintain the invariant that pause
350 // time target < pause interval. If the user does not want this
351 // maximum flexibility, they will have to set the pause interval
352 // explicitly.
353
354 // First make sure that, if either parameter is set, its value is
355 // reasonable.
356 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
357 if (MaxGCPauseMillis < 1) {
358 vm_exit_during_initialization("MaxGCPauseMillis should be "
359 "greater than 0");
360 }
361 }
362 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
363 if (GCPauseIntervalMillis < 1) {
364 vm_exit_during_initialization("GCPauseIntervalMillis should be "
365 "greater than 0");
366 }
367 }
368
369 // Then, if the pause time target parameter was not set, set it to
370 // the default value.
371 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
372 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
373 // The default pause time target in G1 is 200ms
374 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
375 } else {
376 // We do not allow the pause interval to be set without the
377 // pause time target
378 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
379 "without setting MaxGCPauseMillis");
380 }
381 }
382
383 // Then, if the interval parameter was not set, set it according to
384 // the pause time target (this will also deal with the case when the
385 // pause time target is the default value).
386 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
387 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
388 }
389
390 // Finally, make sure that the two parameters are consistent.
391 if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
392 char buffer[256];
393 jio_snprintf(buffer, 256,
394 "MaxGCPauseMillis (%u) should be less than "
395 "GCPauseIntervalMillis (%u)",
396 MaxGCPauseMillis, GCPauseIntervalMillis);
397 vm_exit_during_initialization(buffer);
398 }
399
400 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
401 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
402 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
403 _sigma = (double) G1ConfidencePercent / 100.0;
404
405 // start conservatively (around 50ms is about right)
406 _concurrent_mark_init_times_ms->add(0.05);
407 _concurrent_mark_remark_times_ms->add(0.05);
408 _concurrent_mark_cleanup_times_ms->add(0.20);
409 _tenuring_threshold = MaxTenuringThreshold;
410
411 // if G1FixedSurvivorSpaceSize is 0 which means the size is not
412 // fixed, then _max_survivor_regions will be calculated at
413 // calculate_young_list_target_length during initialization
414 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
415
416 assert(GCTimeRatio > 0,
417 "we should have set it to a default value set_g1_gc_flags() "
418 "if a user set it to 0");
419 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
420
421 initialize_all();
422 }
423
424 // Increment "i", mod "len"
425 static void inc_mod(int& i, int len) {
426 i++; if (i == len) i = 0;
427 }
428
429 void G1CollectorPolicy::initialize_flags() {
430 set_min_alignment(HeapRegion::GrainBytes);
431 set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
432 if (SurvivorRatio < 1) {
433 vm_exit_during_initialization("Invalid survivor ratio specified");
434 }
435 CollectorPolicy::initialize_flags();
436 }
437
438 // The easiest way to deal with the parsing of the NewSize /
439 // MaxNewSize / etc. parameteres is to re-use the code in the
440 // TwoGenerationCollectorPolicy class. This is similar to what
441 // ParallelScavenge does with its GenerationSizer class (see
442 // ParallelScavengeHeap::initialize()). We might change this in the
443 // future, but it's a good start.
444 class G1YoungGenSizer : public TwoGenerationCollectorPolicy {
445 size_t size_to_region_num(size_t byte_size) {
446 return MAX2((size_t) 1, byte_size / HeapRegion::GrainBytes);
447 }
448
449 public:
450 G1YoungGenSizer() {
451 initialize_flags();
452 initialize_size_info();
453 }
454
455 size_t min_young_region_num() {
456 return size_to_region_num(_min_gen0_size);
457 }
458 size_t initial_young_region_num() {
459 return size_to_region_num(_initial_gen0_size);
460 }
461 size_t max_young_region_num() {
462 return size_to_region_num(_max_gen0_size);
463 }
464 };
465
466 void G1CollectorPolicy::init() {
467 // Set aside an initial future to_space.
468 _g1 = G1CollectedHeap::heap();
469
470 assert(Heap_lock->owned_by_self(), "Locking discipline.");
471
472 initialize_gc_policy_counters();
473
474 if (G1Gen) {
475 _in_young_gc_mode = true;
476
477 G1YoungGenSizer sizer;
478 size_t initial_region_num = sizer.initial_young_region_num();
479
480 if (UseAdaptiveSizePolicy) {
481 set_adaptive_young_list_length(true);
482 _young_list_fixed_length = 0;
483 } else {
484 set_adaptive_young_list_length(false);
485 _young_list_fixed_length = initial_region_num;
486 }
487 _free_regions_at_end_of_collection = _g1->free_regions();
488 calculate_young_list_min_length();
489 guarantee( _young_list_min_length == 0, "invariant, not enough info" );
490 calculate_young_list_target_length();
491 } else {
492 _young_list_fixed_length = 0;
493 _in_young_gc_mode = false;
494 }
495
496 // We may immediately start allocating regions and placing them on the
497 // collection set list. Initialize the per-collection set info
498 start_incremental_cset_building();
499 }
500
501 // Create the jstat counters for the policy.
502 void G1CollectorPolicy::initialize_gc_policy_counters()
503 {
504 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen);
505 }
506
507 void G1CollectorPolicy::calculate_young_list_min_length() {
508 _young_list_min_length = 0;
509
510 if (!adaptive_young_list_length())
511 return;
512
513 if (_alloc_rate_ms_seq->num() > 3) {
514 double now_sec = os::elapsedTime();
515 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
516 double alloc_rate_ms = predict_alloc_rate_ms();
517 size_t min_regions = (size_t) ceil(alloc_rate_ms * when_ms);
518 size_t current_region_num = _g1->young_list()->length();
519 _young_list_min_length = min_regions + current_region_num;
520 }
521 }
522
523 void G1CollectorPolicy::calculate_young_list_target_length() {
524 if (adaptive_young_list_length()) {
525 size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
526 calculate_young_list_target_length(rs_lengths);
527 } else {
528 if (full_young_gcs())
529 _young_list_target_length = _young_list_fixed_length;
530 else
531 _young_list_target_length = _young_list_fixed_length / 2;
532 }
533
534 // Make sure we allow the application to allocate at least one
535 // region before we need to do a collection again.
536 size_t min_length = _g1->young_list()->length() + 1;
537 _young_list_target_length = MAX2(_young_list_target_length, min_length);
538 calculate_max_gc_locker_expansion();
539 calculate_survivors_policy();
540 }
541
542 void G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths) {
543 guarantee( adaptive_young_list_length(), "pre-condition" );
544 guarantee( !_in_marking_window || !_last_full_young_gc, "invariant" );
545
546 double start_time_sec = os::elapsedTime();
547 size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1ReservePercent);
548 min_reserve_perc = MIN2((size_t) 50, min_reserve_perc);
549 size_t reserve_regions =
550 (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0);
551
552 if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
553 // we are in fully-young mode and there are free regions in the heap
554
555 double survivor_regions_evac_time =
556 predict_survivor_regions_evac_time();
557
558 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
559 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
560 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
561 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
562 double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards)
563 + survivor_regions_evac_time;
564
565 // the result
566 size_t final_young_length = 0;
567
568 size_t init_free_regions =
569 MAX2((size_t)0, _free_regions_at_end_of_collection - reserve_regions);
570
571 // if we're still under the pause target...
572 if (base_time_ms <= target_pause_time_ms) {
573 // We make sure that the shortest young length that makes sense
574 // fits within the target pause time.
575 size_t min_young_length = 1;
576
577 if (predict_will_fit(min_young_length, base_time_ms,
578 init_free_regions, target_pause_time_ms)) {
579 // The shortest young length will fit within the target pause time;
580 // we'll now check whether the absolute maximum number of young
581 // regions will fit in the target pause time. If not, we'll do
582 // a binary search between min_young_length and max_young_length
583 size_t abs_max_young_length = _free_regions_at_end_of_collection - 1;
584 size_t max_young_length = abs_max_young_length;
585
586 if (max_young_length > min_young_length) {
587 // Let's check if the initial max young length will fit within the
588 // target pause. If so then there is no need to search for a maximal
589 // young length - we'll return the initial maximum
590
591 if (predict_will_fit(max_young_length, base_time_ms,
592 init_free_regions, target_pause_time_ms)) {
593 // The maximum young length will satisfy the target pause time.
594 // We are done so set min young length to this maximum length.
595 // The code after the loop will then set final_young_length using
596 // the value cached in the minimum length.
597 min_young_length = max_young_length;
598 } else {
599 // The maximum possible number of young regions will not fit within
600 // the target pause time so let's search....
601
602 size_t diff = (max_young_length - min_young_length) / 2;
603 max_young_length = min_young_length + diff;
604
605 while (max_young_length > min_young_length) {
606 if (predict_will_fit(max_young_length, base_time_ms,
607 init_free_regions, target_pause_time_ms)) {
608
609 // The current max young length will fit within the target
610 // pause time. Note we do not exit the loop here. By setting
611 // min = max, and then increasing the max below means that
612 // we will continue searching for an upper bound in the
613 // range [max..max+diff]
614 min_young_length = max_young_length;
615 }
616 diff = (max_young_length - min_young_length) / 2;
617 max_young_length = min_young_length + diff;
618 }
619 // the above loop found a maximal young length that will fit
620 // within the target pause time.
621 }
622 assert(min_young_length <= abs_max_young_length, "just checking");
623 }
624 final_young_length = min_young_length;
625 }
626 }
627 // and we're done!
628
629 // we should have at least one region in the target young length
630 _young_list_target_length =
631 final_young_length + _recorded_survivor_regions;
632
633 // let's keep an eye of how long we spend on this calculation
634 // right now, I assume that we'll print it when we need it; we
635 // should really adde it to the breakdown of a pause
636 double end_time_sec = os::elapsedTime();
637 double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
638
639 #ifdef TRACE_CALC_YOUNG_LENGTH
640 // leave this in for debugging, just in case
641 gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT ", "
642 "elapsed %1.2lf ms, (%s%s) " SIZE_FORMAT SIZE_FORMAT,
643 target_pause_time_ms,
644 _young_list_target_length
645 elapsed_time_ms,
646 full_young_gcs() ? "full" : "partial",
647 during_initial_mark_pause() ? " i-m" : "",
648 _in_marking_window,
649 _in_marking_window_im);
650 #endif // TRACE_CALC_YOUNG_LENGTH
651
652 if (_young_list_target_length < _young_list_min_length) {
653 // bummer; this means that, if we do a pause when the maximal
654 // length dictates, we'll violate the pause spacing target (the
655 // min length was calculate based on the application's current
656 // alloc rate);
657
658 // so, we have to bite the bullet, and allocate the minimum
659 // number. We'll violate our target, but we just can't meet it.
660
661 #ifdef TRACE_CALC_YOUNG_LENGTH
662 // leave this in for debugging, just in case
663 gclog_or_tty->print_cr("adjusted target length from "
664 SIZE_FORMAT " to " SIZE_FORMAT,
665 _young_list_target_length, _young_list_min_length);
666 #endif // TRACE_CALC_YOUNG_LENGTH
667
668 _young_list_target_length = _young_list_min_length;
669 }
670 } else {
671 // we are in a partially-young mode or we've run out of regions (due
672 // to evacuation failure)
673
674 #ifdef TRACE_CALC_YOUNG_LENGTH
675 // leave this in for debugging, just in case
676 gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
677 _young_list_min_length);
678 #endif // TRACE_CALC_YOUNG_LENGTH
679 // we'll do the pause as soon as possible by choosing the minimum
680 _young_list_target_length = _young_list_min_length;
681 }
682
683 _rs_lengths_prediction = rs_lengths;
684 }
685
686 // This is used by: calculate_young_list_target_length(rs_length). It
687 // returns true iff:
688 // the predicted pause time for the given young list will not overflow
689 // the target pause time
690 // and:
691 // the predicted amount of surviving data will not overflow the
692 // the amount of free space available for survivor regions.
693 //
694 bool
695 G1CollectorPolicy::predict_will_fit(size_t young_length,
696 double base_time_ms,
697 size_t init_free_regions,
698 double target_pause_time_ms) {
699
700 if (young_length >= init_free_regions)
701 // end condition 1: not enough space for the young regions
702 return false;
703
704 double accum_surv_rate_adj = 0.0;
705 double accum_surv_rate =
706 accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
707
708 size_t bytes_to_copy =
709 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
710
711 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
712
713 double young_other_time_ms =
714 predict_young_other_time_ms(young_length);
715
716 double pause_time_ms =
717 base_time_ms + copy_time_ms + young_other_time_ms;
718
719 if (pause_time_ms > target_pause_time_ms)
720 // end condition 2: over the target pause time
721 return false;
722
723 size_t free_bytes =
724 (init_free_regions - young_length) * HeapRegion::GrainBytes;
725
726 if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes)
727 // end condition 3: out of to-space (conservatively)
728 return false;
729
730 // success!
731 return true;
732 }
733
734 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
735 double survivor_regions_evac_time = 0.0;
736 for (HeapRegion * r = _recorded_survivor_head;
737 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
738 r = r->get_next_young_region()) {
739 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
740 }
741 return survivor_regions_evac_time;
742 }
743
744 void G1CollectorPolicy::check_prediction_validity() {
745 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
746
747 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
748 if (rs_lengths > _rs_lengths_prediction) {
749 // add 10% to avoid having to recalculate often
750 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
751 calculate_young_list_target_length(rs_lengths_prediction);
752 }
753 }
754
755 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
756 bool is_tlab,
757 bool* gc_overhead_limit_was_exceeded) {
758 guarantee(false, "Not using this policy feature yet.");
759 return NULL;
760 }
761
762 // This method controls how a collector handles one or more
763 // of its generations being fully allocated.
764 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
765 bool is_tlab) {
766 guarantee(false, "Not using this policy feature yet.");
767 return NULL;
768 }
769
770
771 #ifndef PRODUCT
772 bool G1CollectorPolicy::verify_young_ages() {
773 HeapRegion* head = _g1->young_list()->first_region();
774 return
775 verify_young_ages(head, _short_lived_surv_rate_group);
776 // also call verify_young_ages on any additional surv rate groups
777 }
778
779 bool
780 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
781 SurvRateGroup *surv_rate_group) {
782 guarantee( surv_rate_group != NULL, "pre-condition" );
783
784 const char* name = surv_rate_group->name();
785 bool ret = true;
786 int prev_age = -1;
787
788 for (HeapRegion* curr = head;
789 curr != NULL;
790 curr = curr->get_next_young_region()) {
791 SurvRateGroup* group = curr->surv_rate_group();
792 if (group == NULL && !curr->is_survivor()) {
793 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
794 ret = false;
795 }
796
797 if (surv_rate_group == group) {
798 int age = curr->age_in_surv_rate_group();
799
800 if (age < 0) {
801 gclog_or_tty->print_cr("## %s: encountered negative age", name);
802 ret = false;
803 }
804
805 if (age <= prev_age) {
806 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
807 "(%d, %d)", name, age, prev_age);
808 ret = false;
809 }
810 prev_age = age;
811 }
812 }
813
814 return ret;
815 }
816 #endif // PRODUCT
817
818 void G1CollectorPolicy::record_full_collection_start() {
819 _cur_collection_start_sec = os::elapsedTime();
820 // Release the future to-space so that it is available for compaction into.
821 _g1->set_full_collection();
822 }
823
824 void G1CollectorPolicy::record_full_collection_end() {
825 // Consider this like a collection pause for the purposes of allocation
826 // since last pause.
827 double end_sec = os::elapsedTime();
828 double full_gc_time_sec = end_sec - _cur_collection_start_sec;
829 double full_gc_time_ms = full_gc_time_sec * 1000.0;
830
831 _all_full_gc_times_ms->add(full_gc_time_ms);
832
833 update_recent_gc_times(end_sec, full_gc_time_ms);
834
835 _g1->clear_full_collection();
836
837 // "Nuke" the heuristics that control the fully/partially young GC
838 // transitions and make sure we start with fully young GCs after the
839 // Full GC.
840 set_full_young_gcs(true);
841 _last_full_young_gc = false;
842 _should_revert_to_full_young_gcs = false;
843 clear_initiate_conc_mark_if_possible();
844 clear_during_initial_mark_pause();
845 _known_garbage_bytes = 0;
846 _known_garbage_ratio = 0.0;
847 _in_marking_window = false;
848 _in_marking_window_im = false;
849
850 _short_lived_surv_rate_group->start_adding_regions();
851 // also call this on any additional surv rate groups
852
853 record_survivor_regions(0, NULL, NULL);
854
855 _prev_region_num_young = _region_num_young;
856 _prev_region_num_tenured = _region_num_tenured;
857
858 _free_regions_at_end_of_collection = _g1->free_regions();
859 // Reset survivors SurvRateGroup.
860 _survivor_surv_rate_group->reset();
861 calculate_young_list_min_length();
862 calculate_young_list_target_length();
863 }
864
865 void G1CollectorPolicy::record_before_bytes(size_t bytes) {
866 _bytes_in_to_space_before_gc += bytes;
867 }
868
869 void G1CollectorPolicy::record_after_bytes(size_t bytes) {
870 _bytes_in_to_space_after_gc += bytes;
871 }
872
873 void G1CollectorPolicy::record_stop_world_start() {
874 _stop_world_start = os::elapsedTime();
875 }
876
877 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
878 size_t start_used) {
879 if (PrintGCDetails) {
880 gclog_or_tty->stamp(PrintGCTimeStamps);
881 gclog_or_tty->print("[GC pause");
882 if (in_young_gc_mode())
883 gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
884 }
885
886 assert(_g1->used() == _g1->recalculate_used(),
887 err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
888 _g1->used(), _g1->recalculate_used()));
889
890 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
891 _all_stop_world_times_ms->add(s_w_t_ms);
892 _stop_world_start = 0.0;
893
894 _cur_collection_start_sec = start_time_sec;
895 _cur_collection_pause_used_at_start_bytes = start_used;
896 _cur_collection_pause_used_regions_at_start = _g1->used_regions();
897 _pending_cards = _g1->pending_card_num();
898 _max_pending_cards = _g1->max_pending_card_num();
899
900 _bytes_in_to_space_before_gc = 0;
901 _bytes_in_to_space_after_gc = 0;
902 _bytes_in_collection_set_before_gc = 0;
903
904 YoungList* young_list = _g1->young_list();
905 _eden_bytes_before_gc = young_list->eden_used_bytes();
906 _survivor_bytes_before_gc = young_list->survivor_used_bytes();
907 _capacity_before_gc = _g1->capacity();
908
909 #ifdef DEBUG
910 // initialise these to something well known so that we can spot
911 // if they are not set properly
912
913 for (int i = 0; i < _parallel_gc_threads; ++i) {
914 _par_last_gc_worker_start_times_ms[i] = -1234.0;
915 _par_last_ext_root_scan_times_ms[i] = -1234.0;
916 _par_last_mark_stack_scan_times_ms[i] = -1234.0;
917 _par_last_update_rs_times_ms[i] = -1234.0;
918 _par_last_update_rs_processed_buffers[i] = -1234.0;
919 _par_last_scan_rs_times_ms[i] = -1234.0;
920 _par_last_obj_copy_times_ms[i] = -1234.0;
921 _par_last_termination_times_ms[i] = -1234.0;
922 _par_last_termination_attempts[i] = -1234.0;
923 _par_last_gc_worker_end_times_ms[i] = -1234.0;
924 _par_last_gc_worker_times_ms[i] = -1234.0;
925 }
926 #endif
927
928 for (int i = 0; i < _aux_num; ++i) {
929 _cur_aux_times_ms[i] = 0.0;
930 _cur_aux_times_set[i] = false;
931 }
932
933 _satb_drain_time_set = false;
934 _last_satb_drain_processed_buffers = -1;
935
936 if (in_young_gc_mode())
937 _last_young_gc_full = false;
938
939 // do that for any other surv rate groups
940 _short_lived_surv_rate_group->stop_adding_regions();
941 _survivors_age_table.clear();
942
943 assert( verify_young_ages(), "region age verification" );
944 }
945
946 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
947 _mark_closure_time_ms = mark_closure_time_ms;
948 }
949
950 void G1CollectorPolicy::record_concurrent_mark_init_start() {
951 _mark_init_start_sec = os::elapsedTime();
952 guarantee(!in_young_gc_mode(), "should not do be here in young GC mode");
953 }
954
955 void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double
956 mark_init_elapsed_time_ms) {
957 _during_marking = true;
958 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
959 clear_during_initial_mark_pause();
960 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
961 }
962
963 void G1CollectorPolicy::record_concurrent_mark_init_end() {
964 double end_time_sec = os::elapsedTime();
965 double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
966 _concurrent_mark_init_times_ms->add(elapsed_time_ms);
967 record_concurrent_mark_init_end_pre(elapsed_time_ms);
968
969 _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true);
970 }
971
972 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
973 _mark_remark_start_sec = os::elapsedTime();
974 _during_marking = false;
975 }
976
977 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
978 double end_time_sec = os::elapsedTime();
979 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
980 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
981 _cur_mark_stop_world_time_ms += elapsed_time_ms;
982 _prev_collection_pause_end_ms += elapsed_time_ms;
983
984 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
985 }
986
987 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
988 _mark_cleanup_start_sec = os::elapsedTime();
989 }
990
991 void
992 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
993 size_t max_live_bytes) {
994 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
995 record_concurrent_mark_cleanup_end_work2();
996 }
997
998 void
999 G1CollectorPolicy::
1000 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
1001 size_t max_live_bytes) {
1002 if (_n_marks < 2) _n_marks++;
1003 if (G1PolicyVerbose > 0)
1004 gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB "
1005 " (of " SIZE_FORMAT " MB heap).",
1006 max_live_bytes/M, _g1->capacity()/M);
1007 }
1008
1009 // The important thing about this is that it includes "os::elapsedTime".
1010 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
1011 double end_time_sec = os::elapsedTime();
1012 double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
1013 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1014 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1015 _prev_collection_pause_end_ms += elapsed_time_ms;
1016
1017 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
1018
1019 _num_markings++;
1020
1021 // We did a marking, so reset the "since_last_mark" variables.
1022 double considerConcMarkCost = 1.0;
1023 // If there are available processors, concurrent activity is free...
1024 if (Threads::number_of_non_daemon_threads() * 2 <
1025 os::active_processor_count()) {
1026 considerConcMarkCost = 0.0;
1027 }
1028 _n_pauses_at_mark_end = _n_pauses;
1029 _n_marks_since_last_pause++;
1030 }
1031
1032 void
1033 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
1034 if (in_young_gc_mode()) {
1035 _should_revert_to_full_young_gcs = false;
1036 _last_full_young_gc = true;
1037 _in_marking_window = false;
1038 if (adaptive_young_list_length())
1039 calculate_young_list_target_length();
1040 }
1041 }
1042
1043 void G1CollectorPolicy::record_concurrent_pause() {
1044 if (_stop_world_start > 0.0) {
1045 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
1046 _all_yield_times_ms->add(yield_ms);
1047 }
1048 }
1049
1050 void G1CollectorPolicy::record_concurrent_pause_end() {
1051 }
1052
1053 void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() {
1054 _cur_CH_strong_roots_end_sec = os::elapsedTime();
1055 _cur_CH_strong_roots_dur_ms =
1056 (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0;
1057 }
1058
1059 void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() {
1060 _cur_G1_strong_roots_end_sec = os::elapsedTime();
1061 _cur_G1_strong_roots_dur_ms =
1062 (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0;
1063 }
1064
1065 template<class T>
1066 T sum_of(T* sum_arr, int start, int n, int N) {
1067 T sum = (T)0;
1068 for (int i = 0; i < n; i++) {
1069 int j = (start + i) % N;
1070 sum += sum_arr[j];
1071 }
1072 return sum;
1073 }
1074
1075 void G1CollectorPolicy::print_par_stats(int level,
1076 const char* str,
1077 double* data) {
1078 double min = data[0], max = data[0];
1079 double total = 0.0;
1080 LineBuffer buf(level);
1081 buf.append("[%s (ms):", str);
1082 for (uint i = 0; i < ParallelGCThreads; ++i) {
1083 double val = data[i];
1084 if (val < min)
1085 min = val;
1086 if (val > max)
1087 max = val;
1088 total += val;
1089 buf.append(" %3.1lf", val);
1090 }
1091 buf.append_and_print_cr("");
1092 double avg = total / (double) ParallelGCThreads;
1093 buf.append_and_print_cr(" Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf, Diff: %5.1lf]",
1094 avg, min, max, max - min);
1095 }
1096
1097 void G1CollectorPolicy::print_par_sizes(int level,
1098 const char* str,
1099 double* data) {
1100 double min = data[0], max = data[0];
1101 double total = 0.0;
1102 LineBuffer buf(level);
1103 buf.append("[%s :", str);
1104 for (uint i = 0; i < ParallelGCThreads; ++i) {
1105 double val = data[i];
1106 if (val < min)
1107 min = val;
1108 if (val > max)
1109 max = val;
1110 total += val;
1111 buf.append(" %d", (int) val);
1112 }
1113 buf.append_and_print_cr("");
1114 double avg = total / (double) ParallelGCThreads;
1115 buf.append_and_print_cr(" Sum: %d, Avg: %d, Min: %d, Max: %d, Diff: %d]",
1116 (int)total, (int)avg, (int)min, (int)max, (int)max - (int)min);
1117 }
1118
1119 void G1CollectorPolicy::print_stats (int level,
1120 const char* str,
1121 double value) {
1122 LineBuffer(level).append_and_print_cr("[%s: %5.1lf ms]", str, value);
1123 }
1124
1125 void G1CollectorPolicy::print_stats (int level,
1126 const char* str,
1127 int value) {
1128 LineBuffer(level).append_and_print_cr("[%s: %d]", str, value);
1129 }
1130
1131 double G1CollectorPolicy::avg_value (double* data) {
1132 if (G1CollectedHeap::use_parallel_gc_threads()) {
1133 double ret = 0.0;
1134 for (uint i = 0; i < ParallelGCThreads; ++i)
1135 ret += data[i];
1136 return ret / (double) ParallelGCThreads;
1137 } else {
1138 return data[0];
1139 }
1140 }
1141
1142 double G1CollectorPolicy::max_value (double* data) {
1143 if (G1CollectedHeap::use_parallel_gc_threads()) {
1144 double ret = data[0];
1145 for (uint i = 1; i < ParallelGCThreads; ++i)
1146 if (data[i] > ret)
1147 ret = data[i];
1148 return ret;
1149 } else {
1150 return data[0];
1151 }
1152 }
1153
1154 double G1CollectorPolicy::sum_of_values (double* data) {
1155 if (G1CollectedHeap::use_parallel_gc_threads()) {
1156 double sum = 0.0;
1157 for (uint i = 0; i < ParallelGCThreads; i++)
1158 sum += data[i];
1159 return sum;
1160 } else {
1161 return data[0];
1162 }
1163 }
1164
1165 double G1CollectorPolicy::max_sum (double* data1,
1166 double* data2) {
1167 double ret = data1[0] + data2[0];
1168
1169 if (G1CollectedHeap::use_parallel_gc_threads()) {
1170 for (uint i = 1; i < ParallelGCThreads; ++i) {
1171 double data = data1[i] + data2[i];
1172 if (data > ret)
1173 ret = data;
1174 }
1175 }
1176 return ret;
1177 }
1178
1179 // Anything below that is considered to be zero
1180 #define MIN_TIMER_GRANULARITY 0.0000001
1181
1182 void G1CollectorPolicy::record_collection_pause_end() {
1183 double end_time_sec = os::elapsedTime();
1184 double elapsed_ms = _last_pause_time_ms;
1185 bool parallel = G1CollectedHeap::use_parallel_gc_threads();
1186 double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0;
1187 size_t rs_size =
1188 _cur_collection_pause_used_regions_at_start - collection_set_size();
1189 size_t cur_used_bytes = _g1->used();
1190 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1191 bool last_pause_included_initial_mark = false;
1192 bool update_stats = !_g1->evacuation_failed();
1193
1194 #ifndef PRODUCT
1195 if (G1YoungSurvRateVerbose) {
1196 gclog_or_tty->print_cr("");
1197 _short_lived_surv_rate_group->print();
1198 // do that for any other surv rate groups too
1199 }
1200 #endif // PRODUCT
1201
1202 if (in_young_gc_mode()) {
1203 last_pause_included_initial_mark = during_initial_mark_pause();
1204 if (last_pause_included_initial_mark)
1205 record_concurrent_mark_init_end_pre(0.0);
1206
1207 size_t min_used_targ =
1208 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
1209
1210
1211 if (!_g1->mark_in_progress() && !_last_full_young_gc) {
1212 assert(!last_pause_included_initial_mark, "invariant");
1213 if (cur_used_bytes > min_used_targ &&
1214 cur_used_bytes > _prev_collection_pause_used_at_end_bytes) {
1215 assert(!during_initial_mark_pause(), "we should not see this here");
1216
1217 // Note: this might have already been set, if during the last
1218 // pause we decided to start a cycle but at the beginning of
1219 // this pause we decided to postpone it. That's OK.
1220 set_initiate_conc_mark_if_possible();
1221 }
1222 }
1223
1224 _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
1225 }
1226
1227 _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
1228 end_time_sec, false);
1229
1230 guarantee(_cur_collection_pause_used_regions_at_start >=
1231 collection_set_size(),
1232 "Negative RS size?");
1233
1234 // This assert is exempted when we're doing parallel collection pauses,
1235 // because the fragmentation caused by the parallel GC allocation buffers
1236 // can lead to more memory being used during collection than was used
1237 // before. Best leave this out until the fragmentation problem is fixed.
1238 // Pauses in which evacuation failed can also lead to negative
1239 // collections, since no space is reclaimed from a region containing an
1240 // object whose evacuation failed.
1241 // Further, we're now always doing parallel collection. But I'm still
1242 // leaving this here as a placeholder for a more precise assertion later.
1243 // (DLD, 10/05.)
1244 assert((true || parallel) // Always using GC LABs now.
1245 || _g1->evacuation_failed()
1246 || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
1247 "Negative collection");
1248
1249 size_t freed_bytes =
1250 _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
1251 size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
1252
1253 double survival_fraction =
1254 (double)surviving_bytes/
1255 (double)_collection_set_bytes_used_before;
1256
1257 _n_pauses++;
1258
1259 if (update_stats) {
1260 _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms);
1261 _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms);
1262 _recent_evac_times_ms->add(evac_ms);
1263 _recent_pause_times_ms->add(elapsed_ms);
1264
1265 _recent_rs_sizes->add(rs_size);
1266
1267 // We exempt parallel collection from this check because Alloc Buffer
1268 // fragmentation can produce negative collections. Same with evac
1269 // failure.
1270 // Further, we're now always doing parallel collection. But I'm still
1271 // leaving this here as a placeholder for a more precise assertion later.
1272 // (DLD, 10/05.
1273 assert((true || parallel)
1274 || _g1->evacuation_failed()
1275 || surviving_bytes <= _collection_set_bytes_used_before,
1276 "Or else negative collection!");
1277 _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
1278 _recent_CS_bytes_surviving->add(surviving_bytes);
1279
1280 // this is where we update the allocation rate of the application
1281 double app_time_ms =
1282 (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
1283 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1284 // This usually happens due to the timer not having the required
1285 // granularity. Some Linuxes are the usual culprits.
1286 // We'll just set it to something (arbitrarily) small.
1287 app_time_ms = 1.0;
1288 }
1289 size_t regions_allocated =
1290 (_region_num_young - _prev_region_num_young) +
1291 (_region_num_tenured - _prev_region_num_tenured);
1292 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1293 _alloc_rate_ms_seq->add(alloc_rate_ms);
1294 _prev_region_num_young = _region_num_young;
1295 _prev_region_num_tenured = _region_num_tenured;
1296
1297 double interval_ms =
1298 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1299 update_recent_gc_times(end_time_sec, elapsed_ms);
1300 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1301 if (recent_avg_pause_time_ratio() < 0.0 ||
1302 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1303 #ifndef PRODUCT
1304 // Dump info to allow post-facto debugging
1305 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1306 gclog_or_tty->print_cr("-------------------------------------------");
1307 gclog_or_tty->print_cr("Recent GC Times (ms):");
1308 _recent_gc_times_ms->dump();
1309 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1310 _recent_prev_end_times_for_all_gcs_sec->dump();
1311 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1312 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1313 // In debug mode, terminate the JVM if the user wants to debug at this point.
1314 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1315 #endif // !PRODUCT
1316 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1317 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1318 if (_recent_avg_pause_time_ratio < 0.0) {
1319 _recent_avg_pause_time_ratio = 0.0;
1320 } else {
1321 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1322 _recent_avg_pause_time_ratio = 1.0;
1323 }
1324 }
1325 }
1326
1327 if (G1PolicyVerbose > 1) {
1328 gclog_or_tty->print_cr(" Recording collection pause(%d)", _n_pauses);
1329 }
1330
1331 PauseSummary* summary = _summary;
1332
1333 double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
1334 double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
1335 double update_rs_time = avg_value(_par_last_update_rs_times_ms);
1336 double update_rs_processed_buffers =
1337 sum_of_values(_par_last_update_rs_processed_buffers);
1338 double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
1339 double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
1340 double termination_time = avg_value(_par_last_termination_times_ms);
1341
1342 double parallel_other_time = _cur_collection_par_time_ms -
1343 (update_rs_time + ext_root_scan_time + mark_stack_scan_time +
1344 scan_rs_time + obj_copy_time + termination_time);
1345 if (update_stats) {
1346 MainBodySummary* body_summary = summary->main_body_summary();
1347 guarantee(body_summary != NULL, "should not be null!");
1348
1349 if (_satb_drain_time_set)
1350 body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
1351 else
1352 body_summary->record_satb_drain_time_ms(0.0);
1353 body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
1354 body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
1355 body_summary->record_update_rs_time_ms(update_rs_time);
1356 body_summary->record_scan_rs_time_ms(scan_rs_time);
1357 body_summary->record_obj_copy_time_ms(obj_copy_time);
1358 if (parallel) {
1359 body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
1360 body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
1361 body_summary->record_termination_time_ms(termination_time);
1362 body_summary->record_parallel_other_time_ms(parallel_other_time);
1363 }
1364 body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
1365 }
1366
1367 if (G1PolicyVerbose > 1) {
1368 gclog_or_tty->print_cr(" ET: %10.6f ms (avg: %10.6f ms)\n"
1369 " CH Strong: %10.6f ms (avg: %10.6f ms)\n"
1370 " G1 Strong: %10.6f ms (avg: %10.6f ms)\n"
1371 " Evac: %10.6f ms (avg: %10.6f ms)\n"
1372 " ET-RS: %10.6f ms (avg: %10.6f ms)\n"
1373 " |RS|: " SIZE_FORMAT,
1374 elapsed_ms, recent_avg_time_for_pauses_ms(),
1375 _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(),
1376 _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(),
1377 evac_ms, recent_avg_time_for_evac_ms(),
1378 scan_rs_time,
1379 recent_avg_time_for_pauses_ms() -
1380 recent_avg_time_for_G1_strong_ms(),
1381 rs_size);
1382
1383 gclog_or_tty->print_cr(" Used at start: " SIZE_FORMAT"K"
1384 " At end " SIZE_FORMAT "K\n"
1385 " garbage : " SIZE_FORMAT "K"
1386 " of " SIZE_FORMAT "K\n"
1387 " survival : %6.2f%% (%6.2f%% avg)",
1388 _cur_collection_pause_used_at_start_bytes/K,
1389 _g1->used()/K, freed_bytes/K,
1390 _collection_set_bytes_used_before/K,
1391 survival_fraction*100.0,
1392 recent_avg_survival_fraction()*100.0);
1393 gclog_or_tty->print_cr(" Recent %% gc pause time: %6.2f",
1394 recent_avg_pause_time_ratio() * 100.0);
1395 }
1396
1397 double other_time_ms = elapsed_ms;
1398
1399 if (_satb_drain_time_set) {
1400 other_time_ms -= _cur_satb_drain_time_ms;
1401 }
1402
1403 if (parallel) {
1404 other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
1405 } else {
1406 other_time_ms -=
1407 update_rs_time +
1408 ext_root_scan_time + mark_stack_scan_time +
1409 scan_rs_time + obj_copy_time;
1410 }
1411
1412 if (PrintGCDetails) {
1413 gclog_or_tty->print_cr("%s, %1.8lf secs]",
1414 (last_pause_included_initial_mark) ? " (initial-mark)" : "",
1415 elapsed_ms / 1000.0);
1416
1417 if (_satb_drain_time_set) {
1418 print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
1419 }
1420 if (_last_satb_drain_processed_buffers >= 0) {
1421 print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
1422 }
1423 if (parallel) {
1424 print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
1425 print_par_stats(2, "GC Worker Start Time", _par_last_gc_worker_start_times_ms);
1426 print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
1427 print_par_sizes(3, "Processed Buffers", _par_last_update_rs_processed_buffers);
1428 print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
1429 print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
1430 print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
1431 print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
1432 print_par_stats(2, "Termination", _par_last_termination_times_ms);
1433 print_par_sizes(3, "Termination Attempts", _par_last_termination_attempts);
1434 print_par_stats(2, "GC Worker End Time", _par_last_gc_worker_end_times_ms);
1435
1436 for (int i = 0; i < _parallel_gc_threads; i++) {
1437 _par_last_gc_worker_times_ms[i] = _par_last_gc_worker_end_times_ms[i] - _par_last_gc_worker_start_times_ms[i];
1438 }
1439 print_par_stats(2, "GC Worker Times", _par_last_gc_worker_times_ms);
1440
1441 print_stats(2, "Other", parallel_other_time);
1442 print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
1443 } else {
1444 print_stats(1, "Update RS", update_rs_time);
1445 print_stats(2, "Processed Buffers",
1446 (int)update_rs_processed_buffers);
1447 print_stats(1, "Ext Root Scanning", ext_root_scan_time);
1448 print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
1449 print_stats(1, "Scan RS", scan_rs_time);
1450 print_stats(1, "Object Copying", obj_copy_time);
1451 }
1452 #ifndef PRODUCT
1453 print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
1454 print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
1455 print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
1456 print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
1457 if (_num_cc_clears > 0) {
1458 print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
1459 }
1460 #endif
1461 print_stats(1, "Other", other_time_ms);
1462 print_stats(2, "Choose CSet", _recorded_young_cset_choice_time_ms);
1463
1464 for (int i = 0; i < _aux_num; ++i) {
1465 if (_cur_aux_times_set[i]) {
1466 char buffer[96];
1467 sprintf(buffer, "Aux%d", i);
1468 print_stats(1, buffer, _cur_aux_times_ms[i]);
1469 }
1470 }
1471 }
1472
1473 _all_pause_times_ms->add(elapsed_ms);
1474 if (update_stats) {
1475 summary->record_total_time_ms(elapsed_ms);
1476 summary->record_other_time_ms(other_time_ms);
1477 }
1478 for (int i = 0; i < _aux_num; ++i)
1479 if (_cur_aux_times_set[i])
1480 _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
1481
1482 // Reset marks-between-pauses counter.
1483 _n_marks_since_last_pause = 0;
1484
1485 // Update the efficiency-since-mark vars.
1486 double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
1487 if (elapsed_ms < MIN_TIMER_GRANULARITY) {
1488 // This usually happens due to the timer not having the required
1489 // granularity. Some Linuxes are the usual culprits.
1490 // We'll just set it to something (arbitrarily) small.
1491 proc_ms = 1.0;
1492 }
1493 double cur_efficiency = (double) freed_bytes / proc_ms;
1494
1495 bool new_in_marking_window = _in_marking_window;
1496 bool new_in_marking_window_im = false;
1497 if (during_initial_mark_pause()) {
1498 new_in_marking_window = true;
1499 new_in_marking_window_im = true;
1500 }
1501
1502 if (in_young_gc_mode()) {
1503 if (_last_full_young_gc) {
1504 set_full_young_gcs(false);
1505 _last_full_young_gc = false;
1506 }
1507
1508 if ( !_last_young_gc_full ) {
1509 if ( _should_revert_to_full_young_gcs ||
1510 _known_garbage_ratio < 0.05 ||
1511 (adaptive_young_list_length() &&
1512 (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) {
1513 set_full_young_gcs(true);
1514 }
1515 }
1516 _should_revert_to_full_young_gcs = false;
1517
1518 if (_last_young_gc_full && !_during_marking)
1519 _young_gc_eff_seq->add(cur_efficiency);
1520 }
1521
1522 _short_lived_surv_rate_group->start_adding_regions();
1523 // do that for any other surv rate groupsx
1524
1525 // <NEW PREDICTION>
1526
1527 if (update_stats) {
1528 double pause_time_ms = elapsed_ms;
1529
1530 size_t diff = 0;
1531 if (_max_pending_cards >= _pending_cards)
1532 diff = _max_pending_cards - _pending_cards;
1533 _pending_card_diff_seq->add((double) diff);
1534
1535 double cost_per_card_ms = 0.0;
1536 if (_pending_cards > 0) {
1537 cost_per_card_ms = update_rs_time / (double) _pending_cards;
1538 _cost_per_card_ms_seq->add(cost_per_card_ms);
1539 }
1540
1541 size_t cards_scanned = _g1->cards_scanned();
1542
1543 double cost_per_entry_ms = 0.0;
1544 if (cards_scanned > 10) {
1545 cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
1546 if (_last_young_gc_full)
1547 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1548 else
1549 _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1550 }
1551
1552 if (_max_rs_lengths > 0) {
1553 double cards_per_entry_ratio =
1554 (double) cards_scanned / (double) _max_rs_lengths;
1555 if (_last_young_gc_full)
1556 _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1557 else
1558 _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1559 }
1560
1561 size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1562 if (rs_length_diff >= 0)
1563 _rs_length_diff_seq->add((double) rs_length_diff);
1564
1565 size_t copied_bytes = surviving_bytes;
1566 double cost_per_byte_ms = 0.0;
1567 if (copied_bytes > 0) {
1568 cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
1569 if (_in_marking_window)
1570 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1571 else
1572 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1573 }
1574
1575 double all_other_time_ms = pause_time_ms -
1576 (update_rs_time + scan_rs_time + obj_copy_time +
1577 _mark_closure_time_ms + termination_time);
1578
1579 double young_other_time_ms = 0.0;
1580 if (_recorded_young_regions > 0) {
1581 young_other_time_ms =
1582 _recorded_young_cset_choice_time_ms +
1583 _recorded_young_free_cset_time_ms;
1584 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1585 (double) _recorded_young_regions);
1586 }
1587 double non_young_other_time_ms = 0.0;
1588 if (_recorded_non_young_regions > 0) {
1589 non_young_other_time_ms =
1590 _recorded_non_young_cset_choice_time_ms +
1591 _recorded_non_young_free_cset_time_ms;
1592
1593 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1594 (double) _recorded_non_young_regions);
1595 }
1596
1597 double constant_other_time_ms = all_other_time_ms -
1598 (young_other_time_ms + non_young_other_time_ms);
1599 _constant_other_time_ms_seq->add(constant_other_time_ms);
1600
1601 double survival_ratio = 0.0;
1602 if (_bytes_in_collection_set_before_gc > 0) {
1603 survival_ratio = (double) bytes_in_to_space_during_gc() /
1604 (double) _bytes_in_collection_set_before_gc;
1605 }
1606
1607 _pending_cards_seq->add((double) _pending_cards);
1608 _scanned_cards_seq->add((double) cards_scanned);
1609 _rs_lengths_seq->add((double) _max_rs_lengths);
1610
1611 double expensive_region_limit_ms =
1612 (double) MaxGCPauseMillis - predict_constant_other_time_ms();
1613 if (expensive_region_limit_ms < 0.0) {
1614 // this means that the other time was predicted to be longer than
1615 // than the max pause time
1616 expensive_region_limit_ms = (double) MaxGCPauseMillis;
1617 }
1618 _expensive_region_limit_ms = expensive_region_limit_ms;
1619
1620 if (PREDICTIONS_VERBOSE) {
1621 gclog_or_tty->print_cr("");
1622 gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
1623 "REGIONS %d %d %d "
1624 "PENDING_CARDS %d %d "
1625 "CARDS_SCANNED %d %d "
1626 "RS_LENGTHS %d %d "
1627 "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
1628 "SURVIVAL_RATIO %1.6lf %1.6lf "
1629 "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
1630 "OTHER_YOUNG %1.6lf %1.6lf "
1631 "OTHER_NON_YOUNG %1.6lf %1.6lf "
1632 "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
1633 "ELAPSED %1.6lf %1.6lf ",
1634 _cur_collection_start_sec,
1635 (!_last_young_gc_full) ? 2 :
1636 (last_pause_included_initial_mark) ? 1 : 0,
1637 _recorded_region_num,
1638 _recorded_young_regions,
1639 _recorded_non_young_regions,
1640 _predicted_pending_cards, _pending_cards,
1641 _predicted_cards_scanned, cards_scanned,
1642 _predicted_rs_lengths, _max_rs_lengths,
1643 _predicted_rs_update_time_ms, update_rs_time,
1644 _predicted_rs_scan_time_ms, scan_rs_time,
1645 _predicted_survival_ratio, survival_ratio,
1646 _predicted_object_copy_time_ms, obj_copy_time,
1647 _predicted_constant_other_time_ms, constant_other_time_ms,
1648 _predicted_young_other_time_ms, young_other_time_ms,
1649 _predicted_non_young_other_time_ms,
1650 non_young_other_time_ms,
1651 _vtime_diff_ms, termination_time,
1652 _predicted_pause_time_ms, elapsed_ms);
1653 }
1654
1655 if (G1PolicyVerbose > 0) {
1656 gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
1657 _predicted_pause_time_ms,
1658 (_within_target) ? "within" : "outside",
1659 elapsed_ms);
1660 }
1661
1662 }
1663
1664 _in_marking_window = new_in_marking_window;
1665 _in_marking_window_im = new_in_marking_window_im;
1666 _free_regions_at_end_of_collection = _g1->free_regions();
1667 calculate_young_list_min_length();
1668 calculate_young_list_target_length();
1669
1670 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1671 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1672 adjust_concurrent_refinement(update_rs_time, update_rs_processed_buffers, update_rs_time_goal_ms);
1673 // </NEW PREDICTION>
1674 }
1675
1676 #define EXT_SIZE_FORMAT "%d%s"
1677 #define EXT_SIZE_PARAMS(bytes) \
1678 byte_size_in_proper_unit((bytes)), \
1679 proper_unit_for_byte_size((bytes))
1680
1681 void G1CollectorPolicy::print_heap_transition() {
1682 if (PrintGCDetails) {
1683 YoungList* young_list = _g1->young_list();
1684 size_t eden_bytes = young_list->eden_used_bytes();
1685 size_t survivor_bytes = young_list->survivor_used_bytes();
1686 size_t used_before_gc = _cur_collection_pause_used_at_start_bytes;
1687 size_t used = _g1->used();
1688 size_t capacity = _g1->capacity();
1689
1690 gclog_or_tty->print_cr(
1691 " [Eden: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1692 "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1693 "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
1694 EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
1695 EXT_SIZE_PARAMS(_eden_bytes_before_gc),
1696 EXT_SIZE_PARAMS(eden_bytes),
1697 EXT_SIZE_PARAMS(_survivor_bytes_before_gc),
1698 EXT_SIZE_PARAMS(survivor_bytes),
1699 EXT_SIZE_PARAMS(used_before_gc),
1700 EXT_SIZE_PARAMS(_capacity_before_gc),
1701 EXT_SIZE_PARAMS(used),
1702 EXT_SIZE_PARAMS(capacity));
1703 } else if (PrintGC) {
1704 _g1->print_size_transition(gclog_or_tty,
1705 _cur_collection_pause_used_at_start_bytes,
1706 _g1->used(), _g1->capacity());
1707 }
1708 }
1709
1710 // <NEW PREDICTION>
1711
1712 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1713 double update_rs_processed_buffers,
1714 double goal_ms) {
1715 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1716 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1717
1718 if (G1UseAdaptiveConcRefinement) {
1719 const int k_gy = 3, k_gr = 6;
1720 const double inc_k = 1.1, dec_k = 0.9;
1721
1722 int g = cg1r->green_zone();
1723 if (update_rs_time > goal_ms) {
1724 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1725 } else {
1726 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1727 g = (int)MAX2(g * inc_k, g + 1.0);
1728 }
1729 }
1730 // Change the refinement threads params
1731 cg1r->set_green_zone(g);
1732 cg1r->set_yellow_zone(g * k_gy);
1733 cg1r->set_red_zone(g * k_gr);
1734 cg1r->reinitialize_threads();
1735
1736 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1737 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1738 cg1r->yellow_zone());
1739 // Change the barrier params
1740 dcqs.set_process_completed_threshold(processing_threshold);
1741 dcqs.set_max_completed_queue(cg1r->red_zone());
1742 }
1743
1744 int curr_queue_size = dcqs.completed_buffers_num();
1745 if (curr_queue_size >= cg1r->yellow_zone()) {
1746 dcqs.set_completed_queue_padding(curr_queue_size);
1747 } else {
1748 dcqs.set_completed_queue_padding(0);
1749 }
1750 dcqs.notify_if_necessary();
1751 }
1752
1753 double
1754 G1CollectorPolicy::
1755 predict_young_collection_elapsed_time_ms(size_t adjustment) {
1756 guarantee( adjustment == 0 || adjustment == 1, "invariant" );
1757
1758 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1759 size_t young_num = g1h->young_list()->length();
1760 if (young_num == 0)
1761 return 0.0;
1762
1763 young_num += adjustment;
1764 size_t pending_cards = predict_pending_cards();
1765 size_t rs_lengths = g1h->young_list()->sampled_rs_lengths() +
1766 predict_rs_length_diff();
1767 size_t card_num;
1768 if (full_young_gcs())
1769 card_num = predict_young_card_num(rs_lengths);
1770 else
1771 card_num = predict_non_young_card_num(rs_lengths);
1772 size_t young_byte_size = young_num * HeapRegion::GrainBytes;
1773 double accum_yg_surv_rate =
1774 _short_lived_surv_rate_group->accum_surv_rate(adjustment);
1775
1776 size_t bytes_to_copy =
1777 (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
1778
1779 return
1780 predict_rs_update_time_ms(pending_cards) +
1781 predict_rs_scan_time_ms(card_num) +
1782 predict_object_copy_time_ms(bytes_to_copy) +
1783 predict_young_other_time_ms(young_num) +
1784 predict_constant_other_time_ms();
1785 }
1786
1787 double
1788 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1789 size_t rs_length = predict_rs_length_diff();
1790 size_t card_num;
1791 if (full_young_gcs())
1792 card_num = predict_young_card_num(rs_length);
1793 else
1794 card_num = predict_non_young_card_num(rs_length);
1795 return predict_base_elapsed_time_ms(pending_cards, card_num);
1796 }
1797
1798 double
1799 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1800 size_t scanned_cards) {
1801 return
1802 predict_rs_update_time_ms(pending_cards) +
1803 predict_rs_scan_time_ms(scanned_cards) +
1804 predict_constant_other_time_ms();
1805 }
1806
1807 double
1808 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1809 bool young) {
1810 size_t rs_length = hr->rem_set()->occupied();
1811 size_t card_num;
1812 if (full_young_gcs())
1813 card_num = predict_young_card_num(rs_length);
1814 else
1815 card_num = predict_non_young_card_num(rs_length);
1816 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1817
1818 double region_elapsed_time_ms =
1819 predict_rs_scan_time_ms(card_num) +
1820 predict_object_copy_time_ms(bytes_to_copy);
1821
1822 if (young)
1823 region_elapsed_time_ms += predict_young_other_time_ms(1);
1824 else
1825 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1826
1827 return region_elapsed_time_ms;
1828 }
1829
1830 size_t
1831 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1832 size_t bytes_to_copy;
1833 if (hr->is_marked())
1834 bytes_to_copy = hr->max_live_bytes();
1835 else {
1836 guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
1837 "invariant" );
1838 int age = hr->age_in_surv_rate_group();
1839 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1840 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1841 }
1842
1843 return bytes_to_copy;
1844 }
1845
1846 void
1847 G1CollectorPolicy::start_recording_regions() {
1848 _recorded_rs_lengths = 0;
1849 _recorded_young_regions = 0;
1850 _recorded_non_young_regions = 0;
1851
1852 #if PREDICTIONS_VERBOSE
1853 _recorded_marked_bytes = 0;
1854 _recorded_young_bytes = 0;
1855 _predicted_bytes_to_copy = 0;
1856 _predicted_rs_lengths = 0;
1857 _predicted_cards_scanned = 0;
1858 #endif // PREDICTIONS_VERBOSE
1859 }
1860
1861 void
1862 G1CollectorPolicy::record_cset_region_info(HeapRegion* hr, bool young) {
1863 #if PREDICTIONS_VERBOSE
1864 if (!young) {
1865 _recorded_marked_bytes += hr->max_live_bytes();
1866 }
1867 _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
1868 #endif // PREDICTIONS_VERBOSE
1869
1870 size_t rs_length = hr->rem_set()->occupied();
1871 _recorded_rs_lengths += rs_length;
1872 }
1873
1874 void
1875 G1CollectorPolicy::record_non_young_cset_region(HeapRegion* hr) {
1876 assert(!hr->is_young(), "should not call this");
1877 ++_recorded_non_young_regions;
1878 record_cset_region_info(hr, false);
1879 }
1880
1881 void
1882 G1CollectorPolicy::set_recorded_young_regions(size_t n_regions) {
1883 _recorded_young_regions = n_regions;
1884 }
1885
1886 void G1CollectorPolicy::set_recorded_young_bytes(size_t bytes) {
1887 #if PREDICTIONS_VERBOSE
1888 _recorded_young_bytes = bytes;
1889 #endif // PREDICTIONS_VERBOSE
1890 }
1891
1892 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1893 _recorded_rs_lengths = rs_lengths;
1894 }
1895
1896 void G1CollectorPolicy::set_predicted_bytes_to_copy(size_t bytes) {
1897 _predicted_bytes_to_copy = bytes;
1898 }
1899
1900 void
1901 G1CollectorPolicy::end_recording_regions() {
1902 // The _predicted_pause_time_ms field is referenced in code
1903 // not under PREDICTIONS_VERBOSE. Let's initialize it.
1904 _predicted_pause_time_ms = -1.0;
1905
1906 #if PREDICTIONS_VERBOSE
1907 _predicted_pending_cards = predict_pending_cards();
1908 _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
1909 if (full_young_gcs())
1910 _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
1911 else
1912 _predicted_cards_scanned +=
1913 predict_non_young_card_num(_predicted_rs_lengths);
1914 _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
1915
1916 _predicted_rs_update_time_ms =
1917 predict_rs_update_time_ms(_g1->pending_card_num());
1918 _predicted_rs_scan_time_ms =
1919 predict_rs_scan_time_ms(_predicted_cards_scanned);
1920 _predicted_object_copy_time_ms =
1921 predict_object_copy_time_ms(_predicted_bytes_to_copy);
1922 _predicted_constant_other_time_ms =
1923 predict_constant_other_time_ms();
1924 _predicted_young_other_time_ms =
1925 predict_young_other_time_ms(_recorded_young_regions);
1926 _predicted_non_young_other_time_ms =
1927 predict_non_young_other_time_ms(_recorded_non_young_regions);
1928
1929 _predicted_pause_time_ms =
1930 _predicted_rs_update_time_ms +
1931 _predicted_rs_scan_time_ms +
1932 _predicted_object_copy_time_ms +
1933 _predicted_constant_other_time_ms +
1934 _predicted_young_other_time_ms +
1935 _predicted_non_young_other_time_ms;
1936 #endif // PREDICTIONS_VERBOSE
1937 }
1938
1939 void G1CollectorPolicy::check_if_region_is_too_expensive(double
1940 predicted_time_ms) {
1941 // I don't think we need to do this when in young GC mode since
1942 // marking will be initiated next time we hit the soft limit anyway...
1943 if (predicted_time_ms > _expensive_region_limit_ms) {
1944 if (!in_young_gc_mode()) {
1945 set_full_young_gcs(true);
1946 // We might want to do something different here. However,
1947 // right now we don't support the non-generational G1 mode
1948 // (and in fact we are planning to remove the associated code,
1949 // see CR 6814390). So, let's leave it as is and this will be
1950 // removed some time in the future
1951 ShouldNotReachHere();
1952 set_during_initial_mark_pause();
1953 } else
1954 // no point in doing another partial one
1955 _should_revert_to_full_young_gcs = true;
1956 }
1957 }
1958
1959 // </NEW PREDICTION>
1960
1961
1962 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1963 double elapsed_ms) {
1964 _recent_gc_times_ms->add(elapsed_ms);
1965 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1966 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1967 }
1968
1969 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
1970 if (_recent_pause_times_ms->num() == 0) return (double) MaxGCPauseMillis;
1971 else return _recent_pause_times_ms->avg();
1972 }
1973
1974 double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() {
1975 if (_recent_CH_strong_roots_times_ms->num() == 0)
1976 return (double)MaxGCPauseMillis/3.0;
1977 else return _recent_CH_strong_roots_times_ms->avg();
1978 }
1979
1980 double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() {
1981 if (_recent_G1_strong_roots_times_ms->num() == 0)
1982 return (double)MaxGCPauseMillis/3.0;
1983 else return _recent_G1_strong_roots_times_ms->avg();
1984 }
1985
1986 double G1CollectorPolicy::recent_avg_time_for_evac_ms() {
1987 if (_recent_evac_times_ms->num() == 0) return (double)MaxGCPauseMillis/3.0;
1988 else return _recent_evac_times_ms->avg();
1989 }
1990
1991 int G1CollectorPolicy::number_of_recent_gcs() {
1992 assert(_recent_CH_strong_roots_times_ms->num() ==
1993 _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync");
1994 assert(_recent_G1_strong_roots_times_ms->num() ==
1995 _recent_evac_times_ms->num(), "Sequence out of sync");
1996 assert(_recent_evac_times_ms->num() ==
1997 _recent_pause_times_ms->num(), "Sequence out of sync");
1998 assert(_recent_pause_times_ms->num() ==
1999 _recent_CS_bytes_used_before->num(), "Sequence out of sync");
2000 assert(_recent_CS_bytes_used_before->num() ==
2001 _recent_CS_bytes_surviving->num(), "Sequence out of sync");
2002 return _recent_pause_times_ms->num();
2003 }
2004
2005 double G1CollectorPolicy::recent_avg_survival_fraction() {
2006 return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
2007 _recent_CS_bytes_used_before);
2008 }
2009
2010 double G1CollectorPolicy::last_survival_fraction() {
2011 return last_survival_fraction_work(_recent_CS_bytes_surviving,
2012 _recent_CS_bytes_used_before);
2013 }
2014
2015 double
2016 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
2017 TruncatedSeq* before) {
2018 assert(surviving->num() == before->num(), "Sequence out of sync");
2019 if (before->sum() > 0.0) {
2020 double recent_survival_rate = surviving->sum() / before->sum();
2021 // We exempt parallel collection from this check because Alloc Buffer
2022 // fragmentation can produce negative collections.
2023 // Further, we're now always doing parallel collection. But I'm still
2024 // leaving this here as a placeholder for a more precise assertion later.
2025 // (DLD, 10/05.)
2026 assert((true || G1CollectedHeap::use_parallel_gc_threads()) ||
2027 _g1->evacuation_failed() ||
2028 recent_survival_rate <= 1.0, "Or bad frac");
2029 return recent_survival_rate;
2030 } else {
2031 return 1.0; // Be conservative.
2032 }
2033 }
2034
2035 double
2036 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
2037 TruncatedSeq* before) {
2038 assert(surviving->num() == before->num(), "Sequence out of sync");
2039 if (surviving->num() > 0 && before->last() > 0.0) {
2040 double last_survival_rate = surviving->last() / before->last();
2041 // We exempt parallel collection from this check because Alloc Buffer
2042 // fragmentation can produce negative collections.
2043 // Further, we're now always doing parallel collection. But I'm still
2044 // leaving this here as a placeholder for a more precise assertion later.
2045 // (DLD, 10/05.)
2046 assert((true || G1CollectedHeap::use_parallel_gc_threads()) ||
2047 last_survival_rate <= 1.0, "Or bad frac");
2048 return last_survival_rate;
2049 } else {
2050 return 1.0;
2051 }
2052 }
2053
2054 static const int survival_min_obs = 5;
2055 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
2056 static const double min_survival_rate = 0.1;
2057
2058 double
2059 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
2060 double latest) {
2061 double res = avg;
2062 if (number_of_recent_gcs() < survival_min_obs) {
2063 res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
2064 }
2065 res = MAX2(res, latest);
2066 res = MAX2(res, min_survival_rate);
2067 // In the parallel case, LAB fragmentation can produce "negative
2068 // collections"; so can evac failure. Cap at 1.0
2069 res = MIN2(res, 1.0);
2070 return res;
2071 }
2072
2073 size_t G1CollectorPolicy::expansion_amount() {
2074 if ((recent_avg_pause_time_ratio() * 100.0) > _gc_overhead_perc) {
2075 // We will double the existing space, or take
2076 // G1ExpandByPercentOfAvailable % of the available expansion
2077 // space, whichever is smaller, bounded below by a minimum
2078 // expansion (unless that's all that's left.)
2079 const size_t min_expand_bytes = 1*M;
2080 size_t reserved_bytes = _g1->max_capacity();
2081 size_t committed_bytes = _g1->capacity();
2082 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
2083 size_t expand_bytes;
2084 size_t expand_bytes_via_pct =
2085 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
2086 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
2087 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
2088 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
2089 if (G1PolicyVerbose > 1) {
2090 gclog_or_tty->print("Decided to expand: ratio = %5.2f, "
2091 "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n"
2092 " Answer = %d.\n",
2093 recent_avg_pause_time_ratio(),
2094 byte_size_in_proper_unit(committed_bytes),
2095 proper_unit_for_byte_size(committed_bytes),
2096 byte_size_in_proper_unit(uncommitted_bytes),
2097 proper_unit_for_byte_size(uncommitted_bytes),
2098 byte_size_in_proper_unit(expand_bytes_via_pct),
2099 proper_unit_for_byte_size(expand_bytes_via_pct),
2100 byte_size_in_proper_unit(expand_bytes),
2101 proper_unit_for_byte_size(expand_bytes));
2102 }
2103 return expand_bytes;
2104 } else {
2105 return 0;
2106 }
2107 }
2108
2109 void G1CollectorPolicy::note_start_of_mark_thread() {
2110 _mark_thread_startup_sec = os::elapsedTime();
2111 }
2112
2113 class CountCSClosure: public HeapRegionClosure {
2114 G1CollectorPolicy* _g1_policy;
2115 public:
2116 CountCSClosure(G1CollectorPolicy* g1_policy) :
2117 _g1_policy(g1_policy) {}
2118 bool doHeapRegion(HeapRegion* r) {
2119 _g1_policy->_bytes_in_collection_set_before_gc += r->used();
2120 return false;
2121 }
2122 };
2123
2124 void G1CollectorPolicy::count_CS_bytes_used() {
2125 CountCSClosure cs_closure(this);
2126 _g1->collection_set_iterate(&cs_closure);
2127 }
2128
2129 void G1CollectorPolicy::print_summary (int level,
2130 const char* str,
2131 NumberSeq* seq) const {
2132 double sum = seq->sum();
2133 LineBuffer(level + 1).append_and_print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
2134 str, sum / 1000.0, seq->avg());
2135 }
2136
2137 void G1CollectorPolicy::print_summary_sd (int level,
2138 const char* str,
2139 NumberSeq* seq) const {
2140 print_summary(level, str, seq);
2141 LineBuffer(level + 6).append_and_print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2142 seq->num(), seq->sd(), seq->maximum());
2143 }
2144
2145 void G1CollectorPolicy::check_other_times(int level,
2146 NumberSeq* other_times_ms,
2147 NumberSeq* calc_other_times_ms) const {
2148 bool should_print = false;
2149 LineBuffer buf(level + 2);
2150
2151 double max_sum = MAX2(fabs(other_times_ms->sum()),
2152 fabs(calc_other_times_ms->sum()));
2153 double min_sum = MIN2(fabs(other_times_ms->sum()),
2154 fabs(calc_other_times_ms->sum()));
2155 double sum_ratio = max_sum / min_sum;
2156 if (sum_ratio > 1.1) {
2157 should_print = true;
2158 buf.append_and_print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
2159 }
2160
2161 double max_avg = MAX2(fabs(other_times_ms->avg()),
2162 fabs(calc_other_times_ms->avg()));
2163 double min_avg = MIN2(fabs(other_times_ms->avg()),
2164 fabs(calc_other_times_ms->avg()));
2165 double avg_ratio = max_avg / min_avg;
2166 if (avg_ratio > 1.1) {
2167 should_print = true;
2168 buf.append_and_print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
2169 }
2170
2171 if (other_times_ms->sum() < -0.01) {
2172 buf.append_and_print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
2173 }
2174
2175 if (other_times_ms->avg() < -0.01) {
2176 buf.append_and_print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
2177 }
2178
2179 if (calc_other_times_ms->sum() < -0.01) {
2180 should_print = true;
2181 buf.append_and_print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
2182 }
2183
2184 if (calc_other_times_ms->avg() < -0.01) {
2185 should_print = true;
2186 buf.append_and_print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
2187 }
2188
2189 if (should_print)
2190 print_summary(level, "Other(Calc)", calc_other_times_ms);
2191 }
2192
2193 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
2194 bool parallel = G1CollectedHeap::use_parallel_gc_threads();
2195 MainBodySummary* body_summary = summary->main_body_summary();
2196 if (summary->get_total_seq()->num() > 0) {
2197 print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
2198 if (body_summary != NULL) {
2199 print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
2200 if (parallel) {
2201 print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
2202 print_summary(2, "Update RS", body_summary->get_update_rs_seq());
2203 print_summary(2, "Ext Root Scanning",
2204 body_summary->get_ext_root_scan_seq());
2205 print_summary(2, "Mark Stack Scanning",
2206 body_summary->get_mark_stack_scan_seq());
2207 print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
2208 print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
2209 print_summary(2, "Termination", body_summary->get_termination_seq());
2210 print_summary(2, "Other", body_summary->get_parallel_other_seq());
2211 {
2212 NumberSeq* other_parts[] = {
2213 body_summary->get_update_rs_seq(),
2214 body_summary->get_ext_root_scan_seq(),
2215 body_summary->get_mark_stack_scan_seq(),
2216 body_summary->get_scan_rs_seq(),
2217 body_summary->get_obj_copy_seq(),
2218 body_summary->get_termination_seq()
2219 };
2220 NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
2221 6, other_parts);
2222 check_other_times(2, body_summary->get_parallel_other_seq(),
2223 &calc_other_times_ms);
2224 }
2225 print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
2226 print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
2227 } else {
2228 print_summary(1, "Update RS", body_summary->get_update_rs_seq());
2229 print_summary(1, "Ext Root Scanning",
2230 body_summary->get_ext_root_scan_seq());
2231 print_summary(1, "Mark Stack Scanning",
2232 body_summary->get_mark_stack_scan_seq());
2233 print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
2234 print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
2235 }
2236 }
2237 print_summary(1, "Other", summary->get_other_seq());
2238 {
2239 if (body_summary != NULL) {
2240 NumberSeq calc_other_times_ms;
2241 if (parallel) {
2242 // parallel
2243 NumberSeq* other_parts[] = {
2244 body_summary->get_satb_drain_seq(),
2245 body_summary->get_parallel_seq(),
2246 body_summary->get_clear_ct_seq()
2247 };
2248 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2249 3, other_parts);
2250 } else {
2251 // serial
2252 NumberSeq* other_parts[] = {
2253 body_summary->get_satb_drain_seq(),
2254 body_summary->get_update_rs_seq(),
2255 body_summary->get_ext_root_scan_seq(),
2256 body_summary->get_mark_stack_scan_seq(),
2257 body_summary->get_scan_rs_seq(),
2258 body_summary->get_obj_copy_seq()
2259 };
2260 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2261 6, other_parts);
2262 }
2263 check_other_times(1, summary->get_other_seq(), &calc_other_times_ms);
2264 }
2265 }
2266 } else {
2267 LineBuffer(1).append_and_print_cr("none");
2268 }
2269 LineBuffer(0).append_and_print_cr("");
2270 }
2271
2272 void G1CollectorPolicy::print_tracing_info() const {
2273 if (TraceGen0Time) {
2274 gclog_or_tty->print_cr("ALL PAUSES");
2275 print_summary_sd(0, "Total", _all_pause_times_ms);
2276 gclog_or_tty->print_cr("");
2277 gclog_or_tty->print_cr("");
2278 gclog_or_tty->print_cr(" Full Young GC Pauses: %8d", _full_young_pause_num);
2279 gclog_or_tty->print_cr(" Partial Young GC Pauses: %8d", _partial_young_pause_num);
2280 gclog_or_tty->print_cr("");
2281
2282 gclog_or_tty->print_cr("EVACUATION PAUSES");
2283 print_summary(_summary);
2284
2285 gclog_or_tty->print_cr("MISC");
2286 print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
2287 print_summary_sd(0, "Yields", _all_yield_times_ms);
2288 for (int i = 0; i < _aux_num; ++i) {
2289 if (_all_aux_times_ms[i].num() > 0) {
2290 char buffer[96];
2291 sprintf(buffer, "Aux%d", i);
2292 print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
2293 }
2294 }
2295
2296 size_t all_region_num = _region_num_young + _region_num_tenured;
2297 gclog_or_tty->print_cr(" New Regions %8d, Young %8d (%6.2lf%%), "
2298 "Tenured %8d (%6.2lf%%)",
2299 all_region_num,
2300 _region_num_young,
2301 (double) _region_num_young / (double) all_region_num * 100.0,
2302 _region_num_tenured,
2303 (double) _region_num_tenured / (double) all_region_num * 100.0);
2304 }
2305 if (TraceGen1Time) {
2306 if (_all_full_gc_times_ms->num() > 0) {
2307 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2308 _all_full_gc_times_ms->num(),
2309 _all_full_gc_times_ms->sum() / 1000.0);
2310 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
2311 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2312 _all_full_gc_times_ms->sd(),
2313 _all_full_gc_times_ms->maximum());
2314 }
2315 }
2316 }
2317
2318 void G1CollectorPolicy::print_yg_surv_rate_info() const {
2319 #ifndef PRODUCT
2320 _short_lived_surv_rate_group->print_surv_rate_summary();
2321 // add this call for any other surv rate groups
2322 #endif // PRODUCT
2323 }
2324
2325 void
2326 G1CollectorPolicy::update_region_num(bool young) {
2327 if (young) {
2328 ++_region_num_young;
2329 } else {
2330 ++_region_num_tenured;
2331 }
2332 }
2333
2334 #ifndef PRODUCT
2335 // for debugging, bit of a hack...
2336 static char*
2337 region_num_to_mbs(int length) {
2338 static char buffer[64];
2339 double bytes = (double) (length * HeapRegion::GrainBytes);
2340 double mbs = bytes / (double) (1024 * 1024);
2341 sprintf(buffer, "%7.2lfMB", mbs);
2342 return buffer;
2343 }
2344 #endif // PRODUCT
2345
2346 size_t G1CollectorPolicy::max_regions(int purpose) {
2347 switch (purpose) {
2348 case GCAllocForSurvived:
2349 return _max_survivor_regions;
2350 case GCAllocForTenured:
2351 return REGIONS_UNLIMITED;
2352 default:
2353 ShouldNotReachHere();
2354 return REGIONS_UNLIMITED;
2355 };
2356 }
2357
2358 void G1CollectorPolicy::calculate_max_gc_locker_expansion() {
2359 size_t expansion_region_num = 0;
2360 if (GCLockerEdenExpansionPercent > 0) {
2361 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
2362 double expansion_region_num_d = perc * (double) _young_list_target_length;
2363 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
2364 // less than 1.0) we'll get 1.
2365 expansion_region_num = (size_t) ceil(expansion_region_num_d);
2366 } else {
2367 assert(expansion_region_num == 0, "sanity");
2368 }
2369 _young_list_max_length = _young_list_target_length + expansion_region_num;
2370 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
2371 }
2372
2373 // Calculates survivor space parameters.
2374 void G1CollectorPolicy::calculate_survivors_policy()
2375 {
2376 if (G1FixedSurvivorSpaceSize == 0) {
2377 _max_survivor_regions = _young_list_target_length / SurvivorRatio;
2378 } else {
2379 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
2380 }
2381
2382 if (G1FixedTenuringThreshold) {
2383 _tenuring_threshold = MaxTenuringThreshold;
2384 } else {
2385 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
2386 HeapRegion::GrainWords * _max_survivor_regions);
2387 }
2388 }
2389
2390 #ifndef PRODUCT
2391 class HRSortIndexIsOKClosure: public HeapRegionClosure {
2392 CollectionSetChooser* _chooser;
2393 public:
2394 HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
2395 _chooser(chooser) {}
2396
2397 bool doHeapRegion(HeapRegion* r) {
2398 if (!r->continuesHumongous()) {
2399 assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
2400 }
2401 return false;
2402 }
2403 };
2404
2405 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
2406 HRSortIndexIsOKClosure cl(_collectionSetChooser);
2407 _g1->heap_region_iterate(&cl);
2408 return true;
2409 }
2410 #endif
2411
2412 bool
2413 G1CollectorPolicy::force_initial_mark_if_outside_cycle() {
2414 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
2415 if (!during_cycle) {
2416 set_initiate_conc_mark_if_possible();
2417 return true;
2418 } else {
2419 return false;
2420 }
2421 }
2422
2423 void
2424 G1CollectorPolicy::decide_on_conc_mark_initiation() {
2425 // We are about to decide on whether this pause will be an
2426 // initial-mark pause.
2427
2428 // First, during_initial_mark_pause() should not be already set. We
2429 // will set it here if we have to. However, it should be cleared by
2430 // the end of the pause (it's only set for the duration of an
2431 // initial-mark pause).
2432 assert(!during_initial_mark_pause(), "pre-condition");
2433
2434 if (initiate_conc_mark_if_possible()) {
2435 // We had noticed on a previous pause that the heap occupancy has
2436 // gone over the initiating threshold and we should start a
2437 // concurrent marking cycle. So we might initiate one.
2438
2439 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
2440 if (!during_cycle) {
2441 // The concurrent marking thread is not "during a cycle", i.e.,
2442 // it has completed the last one. So we can go ahead and
2443 // initiate a new cycle.
2444
2445 set_during_initial_mark_pause();
2446
2447 // And we can now clear initiate_conc_mark_if_possible() as
2448 // we've already acted on it.
2449 clear_initiate_conc_mark_if_possible();
2450 } else {
2451 // The concurrent marking thread is still finishing up the
2452 // previous cycle. If we start one right now the two cycles
2453 // overlap. In particular, the concurrent marking thread might
2454 // be in the process of clearing the next marking bitmap (which
2455 // we will use for the next cycle if we start one). Starting a
2456 // cycle now will be bad given that parts of the marking
2457 // information might get cleared by the marking thread. And we
2458 // cannot wait for the marking thread to finish the cycle as it
2459 // periodically yields while clearing the next marking bitmap
2460 // and, if it's in a yield point, it's waiting for us to
2461 // finish. So, at this point we will not start a cycle and we'll
2462 // let the concurrent marking thread complete the last one.
2463 }
2464 }
2465 }
2466
2467 void
2468 G1CollectorPolicy_BestRegionsFirst::
2469 record_collection_pause_start(double start_time_sec, size_t start_used) {
2470 G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
2471 }
2472
2473 class KnownGarbageClosure: public HeapRegionClosure {
2474 CollectionSetChooser* _hrSorted;
2475
2476 public:
2477 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
2478 _hrSorted(hrSorted)
2479 {}
2480
2481 bool doHeapRegion(HeapRegion* r) {
2482 // We only include humongous regions in collection
2483 // sets when concurrent mark shows that their contained object is
2484 // unreachable.
2485
2486 // Do we have any marking information for this region?
2487 if (r->is_marked()) {
2488 // We don't include humongous regions in collection
2489 // sets because we collect them immediately at the end of a marking
2490 // cycle. We also don't include young regions because we *must*
2491 // include them in the next collection pause.
2492 if (!r->isHumongous() && !r->is_young()) {
2493 _hrSorted->addMarkedHeapRegion(r);
2494 }
2495 }
2496 return false;
2497 }
2498 };
2499
2500 class ParKnownGarbageHRClosure: public HeapRegionClosure {
2501 CollectionSetChooser* _hrSorted;
2502 jint _marked_regions_added;
2503 jint _chunk_size;
2504 jint _cur_chunk_idx;
2505 jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
2506 int _worker;
2507 int _invokes;
2508
2509 void get_new_chunk() {
2510 _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
2511 _cur_chunk_end = _cur_chunk_idx + _chunk_size;
2512 }
2513 void add_region(HeapRegion* r) {
2514 if (_cur_chunk_idx == _cur_chunk_end) {
2515 get_new_chunk();
2516 }
2517 assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
2518 _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
2519 _marked_regions_added++;
2520 _cur_chunk_idx++;
2521 }
2522
2523 public:
2524 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
2525 jint chunk_size,
2526 int worker) :
2527 _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
2528 _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
2529 _invokes(0)
2530 {}
2531
2532 bool doHeapRegion(HeapRegion* r) {
2533 // We only include humongous regions in collection
2534 // sets when concurrent mark shows that their contained object is
2535 // unreachable.
2536 _invokes++;
2537
2538 // Do we have any marking information for this region?
2539 if (r->is_marked()) {
2540 // We don't include humongous regions in collection
2541 // sets because we collect them immediately at the end of a marking
2542 // cycle.
2543 // We also do not include young regions in collection sets
2544 if (!r->isHumongous() && !r->is_young()) {
2545 add_region(r);
2546 }
2547 }
2548 return false;
2549 }
2550 jint marked_regions_added() { return _marked_regions_added; }
2551 int invokes() { return _invokes; }
2552 };
2553
2554 class ParKnownGarbageTask: public AbstractGangTask {
2555 CollectionSetChooser* _hrSorted;
2556 jint _chunk_size;
2557 G1CollectedHeap* _g1;
2558 public:
2559 ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
2560 AbstractGangTask("ParKnownGarbageTask"),
2561 _hrSorted(hrSorted), _chunk_size(chunk_size),
2562 _g1(G1CollectedHeap::heap())
2563 {}
2564
2565 void work(int i) {
2566 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
2567 // Back to zero for the claim value.
2568 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
2569 HeapRegion::InitialClaimValue);
2570 jint regions_added = parKnownGarbageCl.marked_regions_added();
2571 _hrSorted->incNumMarkedHeapRegions(regions_added);
2572 if (G1PrintParCleanupStats) {
2573 gclog_or_tty->print_cr(" Thread %d called %d times, added %d regions to list.",
2574 i, parKnownGarbageCl.invokes(), regions_added);
2575 }
2576 }
2577 };
2578
2579 void
2580 G1CollectorPolicy_BestRegionsFirst::
2581 record_concurrent_mark_cleanup_end(size_t freed_bytes,
2582 size_t max_live_bytes) {
2583 double start;
2584 if (G1PrintParCleanupStats) start = os::elapsedTime();
2585 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
2586
2587 _collectionSetChooser->clearMarkedHeapRegions();
2588 double clear_marked_end;
2589 if (G1PrintParCleanupStats) {
2590 clear_marked_end = os::elapsedTime();
2591 gclog_or_tty->print_cr(" clear marked regions + work1: %8.3f ms.",
2592 (clear_marked_end - start)*1000.0);
2593 }
2594 if (G1CollectedHeap::use_parallel_gc_threads()) {
2595 const size_t OverpartitionFactor = 4;
2596 const size_t MinWorkUnit = 8;
2597 const size_t WorkUnit =
2598 MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
2599 MinWorkUnit);
2600 _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
2601 WorkUnit);
2602 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
2603 (int) WorkUnit);
2604 _g1->workers()->run_task(&parKnownGarbageTask);
2605
2606 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
2607 "sanity check");
2608 } else {
2609 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
2610 _g1->heap_region_iterate(&knownGarbagecl);
2611 }
2612 double known_garbage_end;
2613 if (G1PrintParCleanupStats) {
2614 known_garbage_end = os::elapsedTime();
2615 gclog_or_tty->print_cr(" compute known garbage: %8.3f ms.",
2616 (known_garbage_end - clear_marked_end)*1000.0);
2617 }
2618 _collectionSetChooser->sortMarkedHeapRegions();
2619 double sort_end;
2620 if (G1PrintParCleanupStats) {
2621 sort_end = os::elapsedTime();
2622 gclog_or_tty->print_cr(" sorting: %8.3f ms.",
2623 (sort_end - known_garbage_end)*1000.0);
2624 }
2625
2626 record_concurrent_mark_cleanup_end_work2();
2627 double work2_end;
2628 if (G1PrintParCleanupStats) {
2629 work2_end = os::elapsedTime();
2630 gclog_or_tty->print_cr(" work2: %8.3f ms.",
2631 (work2_end - sort_end)*1000.0);
2632 }
2633 }
2634
2635 // Add the heap region at the head of the non-incremental collection set
2636 void G1CollectorPolicy::
2637 add_to_collection_set(HeapRegion* hr) {
2638 assert(_inc_cset_build_state == Active, "Precondition");
2639 assert(!hr->is_young(), "non-incremental add of young region");
2640
2641 if (_g1->mark_in_progress())
2642 _g1->concurrent_mark()->registerCSetRegion(hr);
2643
2644 assert(!hr->in_collection_set(), "should not already be in the CSet");
2645 hr->set_in_collection_set(true);
2646 hr->set_next_in_collection_set(_collection_set);
2647 _collection_set = hr;
2648 _collection_set_size++;
2649 _collection_set_bytes_used_before += hr->used();
2650 _g1->register_region_with_in_cset_fast_test(hr);
2651 }
2652
2653 // Initialize the per-collection-set information
2654 void G1CollectorPolicy::start_incremental_cset_building() {
2655 assert(_inc_cset_build_state == Inactive, "Precondition");
2656
2657 _inc_cset_head = NULL;
2658 _inc_cset_tail = NULL;
2659 _inc_cset_size = 0;
2660 _inc_cset_bytes_used_before = 0;
2661
2662 if (in_young_gc_mode()) {
2663 _inc_cset_young_index = 0;
2664 }
2665
2666 _inc_cset_max_finger = 0;
2667 _inc_cset_recorded_young_bytes = 0;
2668 _inc_cset_recorded_rs_lengths = 0;
2669 _inc_cset_predicted_elapsed_time_ms = 0;
2670 _inc_cset_predicted_bytes_to_copy = 0;
2671 _inc_cset_build_state = Active;
2672 }
2673
2674 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
2675 // This routine is used when:
2676 // * adding survivor regions to the incremental cset at the end of an
2677 // evacuation pause,
2678 // * adding the current allocation region to the incremental cset
2679 // when it is retired, and
2680 // * updating existing policy information for a region in the
2681 // incremental cset via young list RSet sampling.
2682 // Therefore this routine may be called at a safepoint by the
2683 // VM thread, or in-between safepoints by mutator threads (when
2684 // retiring the current allocation region) or a concurrent
2685 // refine thread (RSet sampling).
2686
2687 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
2688 size_t used_bytes = hr->used();
2689
2690 _inc_cset_recorded_rs_lengths += rs_length;
2691 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
2692
2693 _inc_cset_bytes_used_before += used_bytes;
2694
2695 // Cache the values we have added to the aggregated informtion
2696 // in the heap region in case we have to remove this region from
2697 // the incremental collection set, or it is updated by the
2698 // rset sampling code
2699 hr->set_recorded_rs_length(rs_length);
2700 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
2701
2702 #if PREDICTIONS_VERBOSE
2703 size_t bytes_to_copy = predict_bytes_to_copy(hr);
2704 _inc_cset_predicted_bytes_to_copy += bytes_to_copy;
2705
2706 // Record the number of bytes used in this region
2707 _inc_cset_recorded_young_bytes += used_bytes;
2708
2709 // Cache the values we have added to the aggregated informtion
2710 // in the heap region in case we have to remove this region from
2711 // the incremental collection set, or it is updated by the
2712 // rset sampling code
2713 hr->set_predicted_bytes_to_copy(bytes_to_copy);
2714 #endif // PREDICTIONS_VERBOSE
2715 }
2716
2717 void G1CollectorPolicy::remove_from_incremental_cset_info(HeapRegion* hr) {
2718 // This routine is currently only called as part of the updating of
2719 // existing policy information for regions in the incremental cset that
2720 // is performed by the concurrent refine thread(s) as part of young list
2721 // RSet sampling. Therefore we should not be at a safepoint.
2722
2723 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
2724 assert(hr->is_young(), "it should be");
2725
2726 size_t used_bytes = hr->used();
2727 size_t old_rs_length = hr->recorded_rs_length();
2728 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
2729
2730 // Subtract the old recorded/predicted policy information for
2731 // the given heap region from the collection set info.
2732 _inc_cset_recorded_rs_lengths -= old_rs_length;
2733 _inc_cset_predicted_elapsed_time_ms -= old_elapsed_time_ms;
2734
2735 _inc_cset_bytes_used_before -= used_bytes;
2736
2737 // Clear the values cached in the heap region
2738 hr->set_recorded_rs_length(0);
2739 hr->set_predicted_elapsed_time_ms(0);
2740
2741 #if PREDICTIONS_VERBOSE
2742 size_t old_predicted_bytes_to_copy = hr->predicted_bytes_to_copy();
2743 _inc_cset_predicted_bytes_to_copy -= old_predicted_bytes_to_copy;
2744
2745 // Subtract the number of bytes used in this region
2746 _inc_cset_recorded_young_bytes -= used_bytes;
2747
2748 // Clear the values cached in the heap region
2749 hr->set_predicted_bytes_to_copy(0);
2750 #endif // PREDICTIONS_VERBOSE
2751 }
2752
2753 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length) {
2754 // Update the collection set information that is dependent on the new RS length
2755 assert(hr->is_young(), "Precondition");
2756
2757 remove_from_incremental_cset_info(hr);
2758 add_to_incremental_cset_info(hr, new_rs_length);
2759 }
2760
2761 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
2762 assert( hr->is_young(), "invariant");
2763 assert( hr->young_index_in_cset() == -1, "invariant" );
2764 assert(_inc_cset_build_state == Active, "Precondition");
2765
2766 // We need to clear and set the cached recorded/cached collection set
2767 // information in the heap region here (before the region gets added
2768 // to the collection set). An individual heap region's cached values
2769 // are calculated, aggregated with the policy collection set info,
2770 // and cached in the heap region here (initially) and (subsequently)
2771 // by the Young List sampling code.
2772
2773 size_t rs_length = hr->rem_set()->occupied();
2774 add_to_incremental_cset_info(hr, rs_length);
2775
2776 HeapWord* hr_end = hr->end();
2777 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
2778
2779 assert(!hr->in_collection_set(), "invariant");
2780 hr->set_in_collection_set(true);
2781 assert( hr->next_in_collection_set() == NULL, "invariant");
2782
2783 _inc_cset_size++;
2784 _g1->register_region_with_in_cset_fast_test(hr);
2785
2786 hr->set_young_index_in_cset((int) _inc_cset_young_index);
2787 ++_inc_cset_young_index;
2788 }
2789
2790 // Add the region at the RHS of the incremental cset
2791 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
2792 // We should only ever be appending survivors at the end of a pause
2793 assert( hr->is_survivor(), "Logic");
2794
2795 // Do the 'common' stuff
2796 add_region_to_incremental_cset_common(hr);
2797
2798 // Now add the region at the right hand side
2799 if (_inc_cset_tail == NULL) {
2800 assert(_inc_cset_head == NULL, "invariant");
2801 _inc_cset_head = hr;
2802 } else {
2803 _inc_cset_tail->set_next_in_collection_set(hr);
2804 }
2805 _inc_cset_tail = hr;
2806 }
2807
2808 // Add the region to the LHS of the incremental cset
2809 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
2810 // Survivors should be added to the RHS at the end of a pause
2811 assert(!hr->is_survivor(), "Logic");
2812
2813 // Do the 'common' stuff
2814 add_region_to_incremental_cset_common(hr);
2815
2816 // Add the region at the left hand side
2817 hr->set_next_in_collection_set(_inc_cset_head);
2818 if (_inc_cset_head == NULL) {
2819 assert(_inc_cset_tail == NULL, "Invariant");
2820 _inc_cset_tail = hr;
2821 }
2822 _inc_cset_head = hr;
2823 }
2824
2825 #ifndef PRODUCT
2826 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
2827 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
2828
2829 st->print_cr("\nCollection_set:");
2830 HeapRegion* csr = list_head;
2831 while (csr != NULL) {
2832 HeapRegion* next = csr->next_in_collection_set();
2833 assert(csr->in_collection_set(), "bad CS");
2834 st->print_cr(" [%08x-%08x], t: %08x, P: %08x, N: %08x, C: %08x, "
2835 "age: %4d, y: %d, surv: %d",
2836 csr->bottom(), csr->end(),
2837 csr->top(),
2838 csr->prev_top_at_mark_start(),
2839 csr->next_top_at_mark_start(),
2840 csr->top_at_conc_mark_count(),
2841 csr->age_in_surv_rate_group_cond(),
2842 csr->is_young(),
2843 csr->is_survivor());
2844 csr = next;
2845 }
2846 }
2847 #endif // !PRODUCT
2848
2849 void
2850 G1CollectorPolicy_BestRegionsFirst::choose_collection_set(
2851 double target_pause_time_ms) {
2852 // Set this here - in case we're not doing young collections.
2853 double non_young_start_time_sec = os::elapsedTime();
2854
2855 start_recording_regions();
2856
2857 guarantee(target_pause_time_ms > 0.0,
2858 err_msg("target_pause_time_ms = %1.6lf should be positive",
2859 target_pause_time_ms));
2860 guarantee(_collection_set == NULL, "Precondition");
2861
2862 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2863 double predicted_pause_time_ms = base_time_ms;
2864
2865 double time_remaining_ms = target_pause_time_ms - base_time_ms;
2866
2867 // the 10% and 50% values are arbitrary...
2868 if (time_remaining_ms < 0.10 * target_pause_time_ms) {
2869 time_remaining_ms = 0.50 * target_pause_time_ms;
2870 _within_target = false;
2871 } else {
2872 _within_target = true;
2873 }
2874
2875 // We figure out the number of bytes available for future to-space.
2876 // For new regions without marking information, we must assume the
2877 // worst-case of complete survival. If we have marking information for a
2878 // region, we can bound the amount of live data. We can add a number of
2879 // such regions, as long as the sum of the live data bounds does not
2880 // exceed the available evacuation space.
2881 size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes;
2882
2883 size_t expansion_bytes =
2884 _g1->expansion_regions() * HeapRegion::GrainBytes;
2885
2886 _collection_set_bytes_used_before = 0;
2887 _collection_set_size = 0;
2888
2889 // Adjust for expansion and slop.
2890 max_live_bytes = max_live_bytes + expansion_bytes;
2891
2892 HeapRegion* hr;
2893 if (in_young_gc_mode()) {
2894 double young_start_time_sec = os::elapsedTime();
2895
2896 if (G1PolicyVerbose > 0) {
2897 gclog_or_tty->print_cr("Adding %d young regions to the CSet",
2898 _g1->young_list()->length());
2899 }
2900
2901 _young_cset_length = 0;
2902 _last_young_gc_full = full_young_gcs() ? true : false;
2903
2904 if (_last_young_gc_full)
2905 ++_full_young_pause_num;
2906 else
2907 ++_partial_young_pause_num;
2908
2909 // The young list is laid with the survivor regions from the previous
2910 // pause are appended to the RHS of the young list, i.e.
2911 // [Newly Young Regions ++ Survivors from last pause].
2912
2913 hr = _g1->young_list()->first_survivor_region();
2914 while (hr != NULL) {
2915 assert(hr->is_survivor(), "badly formed young list");
2916 hr->set_young();
2917 hr = hr->get_next_young_region();
2918 }
2919
2920 // Clear the fields that point to the survivor list - they are
2921 // all young now.
2922 _g1->young_list()->clear_survivors();
2923
2924 if (_g1->mark_in_progress())
2925 _g1->concurrent_mark()->register_collection_set_finger(_inc_cset_max_finger);
2926
2927 _young_cset_length = _inc_cset_young_index;
2928 _collection_set = _inc_cset_head;
2929 _collection_set_size = _inc_cset_size;
2930 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2931
2932 // For young regions in the collection set, we assume the worst
2933 // case of complete survival
2934 max_live_bytes -= _inc_cset_size * HeapRegion::GrainBytes;
2935
2936 time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms;
2937 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
2938
2939 // The number of recorded young regions is the incremental
2940 // collection set's current size
2941 set_recorded_young_regions(_inc_cset_size);
2942 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2943 set_recorded_young_bytes(_inc_cset_recorded_young_bytes);
2944 #if PREDICTIONS_VERBOSE
2945 set_predicted_bytes_to_copy(_inc_cset_predicted_bytes_to_copy);
2946 #endif // PREDICTIONS_VERBOSE
2947
2948 if (G1PolicyVerbose > 0) {
2949 gclog_or_tty->print_cr(" Added " PTR_FORMAT " Young Regions to CS.",
2950 _inc_cset_size);
2951 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2952 max_live_bytes/K);
2953 }
2954
2955 assert(_inc_cset_size == _g1->young_list()->length(), "Invariant");
2956
2957 double young_end_time_sec = os::elapsedTime();
2958 _recorded_young_cset_choice_time_ms =
2959 (young_end_time_sec - young_start_time_sec) * 1000.0;
2960
2961 // We are doing young collections so reset this.
2962 non_young_start_time_sec = young_end_time_sec;
2963
2964 // Note we can use either _collection_set_size or
2965 // _young_cset_length here
2966 if (_collection_set_size > 0 && _last_young_gc_full) {
2967 // don't bother adding more regions...
2968 goto choose_collection_set_end;
2969 }
2970 }
2971
2972 if (!in_young_gc_mode() || !full_young_gcs()) {
2973 bool should_continue = true;
2974 NumberSeq seq;
2975 double avg_prediction = 100000000000000000.0; // something very large
2976
2977 do {
2978 hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
2979 avg_prediction);
2980 if (hr != NULL) {
2981 double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
2982 time_remaining_ms -= predicted_time_ms;
2983 predicted_pause_time_ms += predicted_time_ms;
2984 add_to_collection_set(hr);
2985 record_non_young_cset_region(hr);
2986 max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
2987 if (G1PolicyVerbose > 0) {
2988 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2989 max_live_bytes/K);
2990 }
2991 seq.add(predicted_time_ms);
2992 avg_prediction = seq.avg() + seq.sd();
2993 }
2994 should_continue =
2995 ( hr != NULL) &&
2996 ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0
2997 : _collection_set_size < _young_list_fixed_length );
2998 } while (should_continue);
2999
3000 if (!adaptive_young_list_length() &&
3001 _collection_set_size < _young_list_fixed_length)
3002 _should_revert_to_full_young_gcs = true;
3003 }
3004
3005 choose_collection_set_end:
3006 stop_incremental_cset_building();
3007
3008 count_CS_bytes_used();
3009
3010 end_recording_regions();
3011
3012 double non_young_end_time_sec = os::elapsedTime();
3013 _recorded_non_young_cset_choice_time_ms =
3014 (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
3015 }
3016
3017 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
3018 G1CollectorPolicy::record_full_collection_end();
3019 _collectionSetChooser->updateAfterFullCollection();
3020 }
3021
3022 void G1CollectorPolicy_BestRegionsFirst::
3023 expand_if_possible(size_t numRegions) {
3024 size_t expansion_bytes = numRegions * HeapRegion::GrainBytes;
3025 _g1->expand(expansion_bytes);
3026 }
3027
3028 void G1CollectorPolicy_BestRegionsFirst::
3029 record_collection_pause_end() {
3030 G1CollectorPolicy::record_collection_pause_end();
3031 assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
3032 }