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