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