Wed, 02 Jun 2010 22:45:42 -0700
Merge
1 /*
2 * Copyright (c) 2001, 2010, 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 */
25 #include "incls/_precompiled.incl"
26 #include "incls/_g1CollectorPolicy.cpp.incl"
28 #define PREDICTIONS_VERBOSE 0
30 // <NEW PREDICTION>
32 // Different defaults for different number of GC threads
33 // They were chosen by running GCOld and SPECjbb on debris with different
34 // numbers of GC threads and choosing them based on the results
36 // all the same
37 static double rs_length_diff_defaults[] = {
38 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
39 };
41 static double cost_per_card_ms_defaults[] = {
42 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
43 };
45 // all the same
46 static double fully_young_cards_per_entry_ratio_defaults[] = {
47 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
48 };
50 static double cost_per_entry_ms_defaults[] = {
51 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
52 };
54 static double cost_per_byte_ms_defaults[] = {
55 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
56 };
58 // these should be pretty consistent
59 static double constant_other_time_ms_defaults[] = {
60 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
61 };
64 static double young_other_cost_per_region_ms_defaults[] = {
65 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
66 };
68 static double non_young_other_cost_per_region_ms_defaults[] = {
69 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
70 };
72 // </NEW PREDICTION>
74 G1CollectorPolicy::G1CollectorPolicy() :
75 _parallel_gc_threads((ParallelGCThreads > 0) ? ParallelGCThreads : 1),
76 _n_pauses(0),
77 _recent_CH_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
78 _recent_G1_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
79 _recent_evac_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
80 _recent_pause_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
81 _recent_rs_sizes(new TruncatedSeq(NumPrevPausesForHeuristics)),
82 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
83 _all_pause_times_ms(new NumberSeq()),
84 _stop_world_start(0.0),
85 _all_stop_world_times_ms(new NumberSeq()),
86 _all_yield_times_ms(new NumberSeq()),
88 _all_mod_union_times_ms(new NumberSeq()),
90 _summary(new Summary()),
91 _abandoned_summary(new AbandonedSummary()),
93 #ifndef PRODUCT
94 _cur_clear_ct_time_ms(0.0),
95 _min_clear_cc_time_ms(-1.0),
96 _max_clear_cc_time_ms(-1.0),
97 _cur_clear_cc_time_ms(0.0),
98 _cum_clear_cc_time_ms(0.0),
99 _num_cc_clears(0L),
100 #endif
102 _region_num_young(0),
103 _region_num_tenured(0),
104 _prev_region_num_young(0),
105 _prev_region_num_tenured(0),
107 _aux_num(10),
108 _all_aux_times_ms(new NumberSeq[_aux_num]),
109 _cur_aux_start_times_ms(new double[_aux_num]),
110 _cur_aux_times_ms(new double[_aux_num]),
111 _cur_aux_times_set(new bool[_aux_num]),
113 _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
114 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
115 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
117 // <NEW PREDICTION>
119 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
120 _prev_collection_pause_end_ms(0.0),
121 _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
122 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
123 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
124 _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
125 _partially_young_cards_per_entry_ratio_seq(
126 new TruncatedSeq(TruncatedSeqLength)),
127 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
128 _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
129 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
130 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
131 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
132 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
133 _non_young_other_cost_per_region_ms_seq(
134 new TruncatedSeq(TruncatedSeqLength)),
136 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
137 _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
138 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
140 _pause_time_target_ms((double) MaxGCPauseMillis),
142 // </NEW PREDICTION>
144 _in_young_gc_mode(false),
145 _full_young_gcs(true),
146 _full_young_pause_num(0),
147 _partial_young_pause_num(0),
149 _during_marking(false),
150 _in_marking_window(false),
151 _in_marking_window_im(false),
153 _known_garbage_ratio(0.0),
154 _known_garbage_bytes(0),
156 _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
157 _target_pause_time_ms(-1.0),
159 _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
161 _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
162 _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
164 _recent_avg_pause_time_ratio(0.0),
165 _num_markings(0),
166 _n_marks(0),
167 _n_pauses_at_mark_end(0),
169 _all_full_gc_times_ms(new NumberSeq()),
171 // G1PausesBtwnConcMark defaults to -1
172 // so the hack is to do the cast QQQ FIXME
173 _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
174 _n_marks_since_last_pause(0),
175 _initiate_conc_mark_if_possible(false),
176 _during_initial_mark_pause(false),
177 _should_revert_to_full_young_gcs(false),
178 _last_full_young_gc(false),
180 _prev_collection_pause_used_at_end_bytes(0),
182 _collection_set(NULL),
183 _collection_set_size(0),
184 _collection_set_bytes_used_before(0),
186 // Incremental CSet attributes
187 _inc_cset_build_state(Inactive),
188 _inc_cset_head(NULL),
189 _inc_cset_tail(NULL),
190 _inc_cset_size(0),
191 _inc_cset_young_index(0),
192 _inc_cset_bytes_used_before(0),
193 _inc_cset_max_finger(NULL),
194 _inc_cset_recorded_young_bytes(0),
195 _inc_cset_recorded_rs_lengths(0),
196 _inc_cset_predicted_elapsed_time_ms(0.0),
197 _inc_cset_predicted_bytes_to_copy(0),
199 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
200 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
201 #endif // _MSC_VER
203 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
204 G1YoungSurvRateNumRegionsSummary)),
205 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
206 G1YoungSurvRateNumRegionsSummary)),
207 // add here any more surv rate groups
208 _recorded_survivor_regions(0),
209 _recorded_survivor_head(NULL),
210 _recorded_survivor_tail(NULL),
211 _survivors_age_table(true),
213 _gc_overhead_perc(0.0)
215 {
216 // Set up the region size and associated fields. Given that the
217 // policy is created before the heap, we have to set this up here,
218 // so it's done as soon as possible.
219 HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
220 HeapRegionRemSet::setup_remset_size();
222 // Verify PLAB sizes
223 const uint region_size = HeapRegion::GrainWords;
224 if (YoungPLABSize > region_size || OldPLABSize > region_size) {
225 char buffer[128];
226 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most %u",
227 OldPLABSize > region_size ? "Old" : "Young", region_size);
228 vm_exit_during_initialization(buffer);
229 }
231 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
232 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
234 _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
235 _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
237 _par_last_update_rs_start_times_ms = new double[_parallel_gc_threads];
238 _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
239 _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
241 _par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads];
242 _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
243 _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads];
245 _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
247 _par_last_termination_times_ms = new double[_parallel_gc_threads];
249 // start conservatively
250 _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
252 // <NEW PREDICTION>
254 int index;
255 if (ParallelGCThreads == 0)
256 index = 0;
257 else if (ParallelGCThreads > 8)
258 index = 7;
259 else
260 index = ParallelGCThreads - 1;
262 _pending_card_diff_seq->add(0.0);
263 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
264 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
265 _fully_young_cards_per_entry_ratio_seq->add(
266 fully_young_cards_per_entry_ratio_defaults[index]);
267 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
268 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
269 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
270 _young_other_cost_per_region_ms_seq->add(
271 young_other_cost_per_region_ms_defaults[index]);
272 _non_young_other_cost_per_region_ms_seq->add(
273 non_young_other_cost_per_region_ms_defaults[index]);
275 // </NEW PREDICTION>
277 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
278 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
279 guarantee(max_gc_time < time_slice,
280 "Max GC time should not be greater than the time slice");
281 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
282 _sigma = (double) G1ConfidencePercent / 100.0;
284 // start conservatively (around 50ms is about right)
285 _concurrent_mark_init_times_ms->add(0.05);
286 _concurrent_mark_remark_times_ms->add(0.05);
287 _concurrent_mark_cleanup_times_ms->add(0.20);
288 _tenuring_threshold = MaxTenuringThreshold;
290 // if G1FixedSurvivorSpaceSize is 0 which means the size is not
291 // fixed, then _max_survivor_regions will be calculated at
292 // calculate_young_list_target_length during initialization
293 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
295 assert(GCTimeRatio > 0,
296 "we should have set it to a default value set_g1_gc_flags() "
297 "if a user set it to 0");
298 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
300 initialize_all();
301 }
303 // Increment "i", mod "len"
304 static void inc_mod(int& i, int len) {
305 i++; if (i == len) i = 0;
306 }
308 void G1CollectorPolicy::initialize_flags() {
309 set_min_alignment(HeapRegion::GrainBytes);
310 set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
311 if (SurvivorRatio < 1) {
312 vm_exit_during_initialization("Invalid survivor ratio specified");
313 }
314 CollectorPolicy::initialize_flags();
315 }
317 // The easiest way to deal with the parsing of the NewSize /
318 // MaxNewSize / etc. parameteres is to re-use the code in the
319 // TwoGenerationCollectorPolicy class. This is similar to what
320 // ParallelScavenge does with its GenerationSizer class (see
321 // ParallelScavengeHeap::initialize()). We might change this in the
322 // future, but it's a good start.
323 class G1YoungGenSizer : public TwoGenerationCollectorPolicy {
324 size_t size_to_region_num(size_t byte_size) {
325 return MAX2((size_t) 1, byte_size / HeapRegion::GrainBytes);
326 }
328 public:
329 G1YoungGenSizer() {
330 initialize_flags();
331 initialize_size_info();
332 }
334 size_t min_young_region_num() {
335 return size_to_region_num(_min_gen0_size);
336 }
337 size_t initial_young_region_num() {
338 return size_to_region_num(_initial_gen0_size);
339 }
340 size_t max_young_region_num() {
341 return size_to_region_num(_max_gen0_size);
342 }
343 };
345 void G1CollectorPolicy::init() {
346 // Set aside an initial future to_space.
347 _g1 = G1CollectedHeap::heap();
349 assert(Heap_lock->owned_by_self(), "Locking discipline.");
351 initialize_gc_policy_counters();
353 if (G1Gen) {
354 _in_young_gc_mode = true;
356 G1YoungGenSizer sizer;
357 size_t initial_region_num = sizer.initial_young_region_num();
359 if (UseAdaptiveSizePolicy) {
360 set_adaptive_young_list_length(true);
361 _young_list_fixed_length = 0;
362 } else {
363 set_adaptive_young_list_length(false);
364 _young_list_fixed_length = initial_region_num;
365 }
366 _free_regions_at_end_of_collection = _g1->free_regions();
367 calculate_young_list_min_length();
368 guarantee( _young_list_min_length == 0, "invariant, not enough info" );
369 calculate_young_list_target_length();
370 } else {
371 _young_list_fixed_length = 0;
372 _in_young_gc_mode = false;
373 }
375 // We may immediately start allocating regions and placing them on the
376 // collection set list. Initialize the per-collection set info
377 start_incremental_cset_building();
378 }
380 // Create the jstat counters for the policy.
381 void G1CollectorPolicy::initialize_gc_policy_counters()
382 {
383 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen);
384 }
386 void G1CollectorPolicy::calculate_young_list_min_length() {
387 _young_list_min_length = 0;
389 if (!adaptive_young_list_length())
390 return;
392 if (_alloc_rate_ms_seq->num() > 3) {
393 double now_sec = os::elapsedTime();
394 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
395 double alloc_rate_ms = predict_alloc_rate_ms();
396 int min_regions = (int) ceil(alloc_rate_ms * when_ms);
397 int current_region_num = (int) _g1->young_list()->length();
398 _young_list_min_length = min_regions + current_region_num;
399 }
400 }
402 void G1CollectorPolicy::calculate_young_list_target_length() {
403 if (adaptive_young_list_length()) {
404 size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
405 calculate_young_list_target_length(rs_lengths);
406 } else {
407 if (full_young_gcs())
408 _young_list_target_length = _young_list_fixed_length;
409 else
410 _young_list_target_length = _young_list_fixed_length / 2;
412 _young_list_target_length = MAX2(_young_list_target_length, (size_t)1);
413 }
414 calculate_survivors_policy();
415 }
417 void G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths) {
418 guarantee( adaptive_young_list_length(), "pre-condition" );
419 guarantee( !_in_marking_window || !_last_full_young_gc, "invariant" );
421 double start_time_sec = os::elapsedTime();
422 size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1ReservePercent);
423 min_reserve_perc = MIN2((size_t) 50, min_reserve_perc);
424 size_t reserve_regions =
425 (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0);
427 if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
428 // we are in fully-young mode and there are free regions in the heap
430 double survivor_regions_evac_time =
431 predict_survivor_regions_evac_time();
433 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
434 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
435 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
436 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
437 double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards)
438 + survivor_regions_evac_time;
440 // the result
441 size_t final_young_length = 0;
443 size_t init_free_regions =
444 MAX2((size_t)0, _free_regions_at_end_of_collection - reserve_regions);
446 // if we're still under the pause target...
447 if (base_time_ms <= target_pause_time_ms) {
448 // We make sure that the shortest young length that makes sense
449 // fits within the target pause time.
450 size_t min_young_length = 1;
452 if (predict_will_fit(min_young_length, base_time_ms,
453 init_free_regions, target_pause_time_ms)) {
454 // The shortest young length will fit within the target pause time;
455 // we'll now check whether the absolute maximum number of young
456 // regions will fit in the target pause time. If not, we'll do
457 // a binary search between min_young_length and max_young_length
458 size_t abs_max_young_length = _free_regions_at_end_of_collection - 1;
459 size_t max_young_length = abs_max_young_length;
461 if (max_young_length > min_young_length) {
462 // Let's check if the initial max young length will fit within the
463 // target pause. If so then there is no need to search for a maximal
464 // young length - we'll return the initial maximum
466 if (predict_will_fit(max_young_length, base_time_ms,
467 init_free_regions, target_pause_time_ms)) {
468 // The maximum young length will satisfy the target pause time.
469 // We are done so set min young length to this maximum length.
470 // The code after the loop will then set final_young_length using
471 // the value cached in the minimum length.
472 min_young_length = max_young_length;
473 } else {
474 // The maximum possible number of young regions will not fit within
475 // the target pause time so let's search....
477 size_t diff = (max_young_length - min_young_length) / 2;
478 max_young_length = min_young_length + diff;
480 while (max_young_length > min_young_length) {
481 if (predict_will_fit(max_young_length, base_time_ms,
482 init_free_regions, target_pause_time_ms)) {
484 // The current max young length will fit within the target
485 // pause time. Note we do not exit the loop here. By setting
486 // min = max, and then increasing the max below means that
487 // we will continue searching for an upper bound in the
488 // range [max..max+diff]
489 min_young_length = max_young_length;
490 }
491 diff = (max_young_length - min_young_length) / 2;
492 max_young_length = min_young_length + diff;
493 }
494 // the above loop found a maximal young length that will fit
495 // within the target pause time.
496 }
497 assert(min_young_length <= abs_max_young_length, "just checking");
498 }
499 final_young_length = min_young_length;
500 }
501 }
502 // and we're done!
504 // we should have at least one region in the target young length
505 _young_list_target_length =
506 MAX2((size_t) 1, final_young_length + _recorded_survivor_regions);
508 // let's keep an eye of how long we spend on this calculation
509 // right now, I assume that we'll print it when we need it; we
510 // should really adde it to the breakdown of a pause
511 double end_time_sec = os::elapsedTime();
512 double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
514 #ifdef TRACE_CALC_YOUNG_LENGTH
515 // leave this in for debugging, just in case
516 gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT ", "
517 "elapsed %1.2lf ms, (%s%s) " SIZE_FORMAT SIZE_FORMAT,
518 target_pause_time_ms,
519 _young_list_target_length
520 elapsed_time_ms,
521 full_young_gcs() ? "full" : "partial",
522 during_initial_mark_pause() ? " i-m" : "",
523 _in_marking_window,
524 _in_marking_window_im);
525 #endif // TRACE_CALC_YOUNG_LENGTH
527 if (_young_list_target_length < _young_list_min_length) {
528 // bummer; this means that, if we do a pause when the maximal
529 // length dictates, we'll violate the pause spacing target (the
530 // min length was calculate based on the application's current
531 // alloc rate);
533 // so, we have to bite the bullet, and allocate the minimum
534 // number. We'll violate our target, but we just can't meet it.
536 #ifdef TRACE_CALC_YOUNG_LENGTH
537 // leave this in for debugging, just in case
538 gclog_or_tty->print_cr("adjusted target length from "
539 SIZE_FORMAT " to " SIZE_FORMAT,
540 _young_list_target_length, _young_list_min_length);
541 #endif // TRACE_CALC_YOUNG_LENGTH
543 _young_list_target_length = _young_list_min_length;
544 }
545 } else {
546 // we are in a partially-young mode or we've run out of regions (due
547 // to evacuation failure)
549 #ifdef TRACE_CALC_YOUNG_LENGTH
550 // leave this in for debugging, just in case
551 gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
552 _young_list_min_length);
553 #endif // TRACE_CALC_YOUNG_LENGTH
554 // we'll do the pause as soon as possible by choosing the minimum
555 _young_list_target_length =
556 MAX2(_young_list_min_length, (size_t) 1);
557 }
559 _rs_lengths_prediction = rs_lengths;
560 }
562 // This is used by: calculate_young_list_target_length(rs_length). It
563 // returns true iff:
564 // the predicted pause time for the given young list will not overflow
565 // the target pause time
566 // and:
567 // the predicted amount of surviving data will not overflow the
568 // the amount of free space available for survivor regions.
569 //
570 bool
571 G1CollectorPolicy::predict_will_fit(size_t young_length,
572 double base_time_ms,
573 size_t init_free_regions,
574 double target_pause_time_ms) {
576 if (young_length >= init_free_regions)
577 // end condition 1: not enough space for the young regions
578 return false;
580 double accum_surv_rate_adj = 0.0;
581 double accum_surv_rate =
582 accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
584 size_t bytes_to_copy =
585 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
587 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
589 double young_other_time_ms =
590 predict_young_other_time_ms(young_length);
592 double pause_time_ms =
593 base_time_ms + copy_time_ms + young_other_time_ms;
595 if (pause_time_ms > target_pause_time_ms)
596 // end condition 2: over the target pause time
597 return false;
599 size_t free_bytes =
600 (init_free_regions - young_length) * HeapRegion::GrainBytes;
602 if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes)
603 // end condition 3: out of to-space (conservatively)
604 return false;
606 // success!
607 return true;
608 }
610 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
611 double survivor_regions_evac_time = 0.0;
612 for (HeapRegion * r = _recorded_survivor_head;
613 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
614 r = r->get_next_young_region()) {
615 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
616 }
617 return survivor_regions_evac_time;
618 }
620 void G1CollectorPolicy::check_prediction_validity() {
621 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
623 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
624 if (rs_lengths > _rs_lengths_prediction) {
625 // add 10% to avoid having to recalculate often
626 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
627 calculate_young_list_target_length(rs_lengths_prediction);
628 }
629 }
631 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
632 bool is_tlab,
633 bool* gc_overhead_limit_was_exceeded) {
634 guarantee(false, "Not using this policy feature yet.");
635 return NULL;
636 }
638 // This method controls how a collector handles one or more
639 // of its generations being fully allocated.
640 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
641 bool is_tlab) {
642 guarantee(false, "Not using this policy feature yet.");
643 return NULL;
644 }
647 #ifndef PRODUCT
648 bool G1CollectorPolicy::verify_young_ages() {
649 HeapRegion* head = _g1->young_list()->first_region();
650 return
651 verify_young_ages(head, _short_lived_surv_rate_group);
652 // also call verify_young_ages on any additional surv rate groups
653 }
655 bool
656 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
657 SurvRateGroup *surv_rate_group) {
658 guarantee( surv_rate_group != NULL, "pre-condition" );
660 const char* name = surv_rate_group->name();
661 bool ret = true;
662 int prev_age = -1;
664 for (HeapRegion* curr = head;
665 curr != NULL;
666 curr = curr->get_next_young_region()) {
667 SurvRateGroup* group = curr->surv_rate_group();
668 if (group == NULL && !curr->is_survivor()) {
669 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
670 ret = false;
671 }
673 if (surv_rate_group == group) {
674 int age = curr->age_in_surv_rate_group();
676 if (age < 0) {
677 gclog_or_tty->print_cr("## %s: encountered negative age", name);
678 ret = false;
679 }
681 if (age <= prev_age) {
682 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
683 "(%d, %d)", name, age, prev_age);
684 ret = false;
685 }
686 prev_age = age;
687 }
688 }
690 return ret;
691 }
692 #endif // PRODUCT
694 void G1CollectorPolicy::record_full_collection_start() {
695 _cur_collection_start_sec = os::elapsedTime();
696 // Release the future to-space so that it is available for compaction into.
697 _g1->set_full_collection();
698 }
700 void G1CollectorPolicy::record_full_collection_end() {
701 // Consider this like a collection pause for the purposes of allocation
702 // since last pause.
703 double end_sec = os::elapsedTime();
704 double full_gc_time_sec = end_sec - _cur_collection_start_sec;
705 double full_gc_time_ms = full_gc_time_sec * 1000.0;
707 _all_full_gc_times_ms->add(full_gc_time_ms);
709 update_recent_gc_times(end_sec, full_gc_time_ms);
711 _g1->clear_full_collection();
713 // "Nuke" the heuristics that control the fully/partially young GC
714 // transitions and make sure we start with fully young GCs after the
715 // Full GC.
716 set_full_young_gcs(true);
717 _last_full_young_gc = false;
718 _should_revert_to_full_young_gcs = false;
719 clear_initiate_conc_mark_if_possible();
720 clear_during_initial_mark_pause();
721 _known_garbage_bytes = 0;
722 _known_garbage_ratio = 0.0;
723 _in_marking_window = false;
724 _in_marking_window_im = false;
726 _short_lived_surv_rate_group->start_adding_regions();
727 // also call this on any additional surv rate groups
729 record_survivor_regions(0, NULL, NULL);
731 _prev_region_num_young = _region_num_young;
732 _prev_region_num_tenured = _region_num_tenured;
734 _free_regions_at_end_of_collection = _g1->free_regions();
735 // Reset survivors SurvRateGroup.
736 _survivor_surv_rate_group->reset();
737 calculate_young_list_min_length();
738 calculate_young_list_target_length();
739 }
741 void G1CollectorPolicy::record_before_bytes(size_t bytes) {
742 _bytes_in_to_space_before_gc += bytes;
743 }
745 void G1CollectorPolicy::record_after_bytes(size_t bytes) {
746 _bytes_in_to_space_after_gc += bytes;
747 }
749 void G1CollectorPolicy::record_stop_world_start() {
750 _stop_world_start = os::elapsedTime();
751 }
753 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
754 size_t start_used) {
755 if (PrintGCDetails) {
756 gclog_or_tty->stamp(PrintGCTimeStamps);
757 gclog_or_tty->print("[GC pause");
758 if (in_young_gc_mode())
759 gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
760 }
762 assert(_g1->used_regions() == _g1->recalculate_used_regions(),
763 "sanity");
764 assert(_g1->used() == _g1->recalculate_used(), "sanity");
766 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
767 _all_stop_world_times_ms->add(s_w_t_ms);
768 _stop_world_start = 0.0;
770 _cur_collection_start_sec = start_time_sec;
771 _cur_collection_pause_used_at_start_bytes = start_used;
772 _cur_collection_pause_used_regions_at_start = _g1->used_regions();
773 _pending_cards = _g1->pending_card_num();
774 _max_pending_cards = _g1->max_pending_card_num();
776 _bytes_in_to_space_before_gc = 0;
777 _bytes_in_to_space_after_gc = 0;
778 _bytes_in_collection_set_before_gc = 0;
780 #ifdef DEBUG
781 // initialise these to something well known so that we can spot
782 // if they are not set properly
784 for (int i = 0; i < _parallel_gc_threads; ++i) {
785 _par_last_ext_root_scan_times_ms[i] = -666.0;
786 _par_last_mark_stack_scan_times_ms[i] = -666.0;
787 _par_last_update_rs_start_times_ms[i] = -666.0;
788 _par_last_update_rs_times_ms[i] = -666.0;
789 _par_last_update_rs_processed_buffers[i] = -666.0;
790 _par_last_scan_rs_start_times_ms[i] = -666.0;
791 _par_last_scan_rs_times_ms[i] = -666.0;
792 _par_last_scan_new_refs_times_ms[i] = -666.0;
793 _par_last_obj_copy_times_ms[i] = -666.0;
794 _par_last_termination_times_ms[i] = -666.0;
795 }
796 #endif
798 for (int i = 0; i < _aux_num; ++i) {
799 _cur_aux_times_ms[i] = 0.0;
800 _cur_aux_times_set[i] = false;
801 }
803 _satb_drain_time_set = false;
804 _last_satb_drain_processed_buffers = -1;
806 if (in_young_gc_mode())
807 _last_young_gc_full = false;
809 // do that for any other surv rate groups
810 _short_lived_surv_rate_group->stop_adding_regions();
811 _survivors_age_table.clear();
813 assert( verify_young_ages(), "region age verification" );
814 }
816 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
817 _mark_closure_time_ms = mark_closure_time_ms;
818 }
820 void G1CollectorPolicy::record_concurrent_mark_init_start() {
821 _mark_init_start_sec = os::elapsedTime();
822 guarantee(!in_young_gc_mode(), "should not do be here in young GC mode");
823 }
825 void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double
826 mark_init_elapsed_time_ms) {
827 _during_marking = true;
828 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
829 clear_during_initial_mark_pause();
830 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
831 }
833 void G1CollectorPolicy::record_concurrent_mark_init_end() {
834 double end_time_sec = os::elapsedTime();
835 double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
836 _concurrent_mark_init_times_ms->add(elapsed_time_ms);
837 record_concurrent_mark_init_end_pre(elapsed_time_ms);
839 _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true);
840 }
842 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
843 _mark_remark_start_sec = os::elapsedTime();
844 _during_marking = false;
845 }
847 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
848 double end_time_sec = os::elapsedTime();
849 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
850 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
851 _cur_mark_stop_world_time_ms += elapsed_time_ms;
852 _prev_collection_pause_end_ms += elapsed_time_ms;
854 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
855 }
857 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
858 _mark_cleanup_start_sec = os::elapsedTime();
859 }
861 void
862 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
863 size_t max_live_bytes) {
864 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
865 record_concurrent_mark_cleanup_end_work2();
866 }
868 void
869 G1CollectorPolicy::
870 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
871 size_t max_live_bytes) {
872 if (_n_marks < 2) _n_marks++;
873 if (G1PolicyVerbose > 0)
874 gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB "
875 " (of " SIZE_FORMAT " MB heap).",
876 max_live_bytes/M, _g1->capacity()/M);
877 }
879 // The important thing about this is that it includes "os::elapsedTime".
880 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
881 double end_time_sec = os::elapsedTime();
882 double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
883 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
884 _cur_mark_stop_world_time_ms += elapsed_time_ms;
885 _prev_collection_pause_end_ms += elapsed_time_ms;
887 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
889 _num_markings++;
891 // We did a marking, so reset the "since_last_mark" variables.
892 double considerConcMarkCost = 1.0;
893 // If there are available processors, concurrent activity is free...
894 if (Threads::number_of_non_daemon_threads() * 2 <
895 os::active_processor_count()) {
896 considerConcMarkCost = 0.0;
897 }
898 _n_pauses_at_mark_end = _n_pauses;
899 _n_marks_since_last_pause++;
900 }
902 void
903 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
904 if (in_young_gc_mode()) {
905 _should_revert_to_full_young_gcs = false;
906 _last_full_young_gc = true;
907 _in_marking_window = false;
908 if (adaptive_young_list_length())
909 calculate_young_list_target_length();
910 }
911 }
913 void G1CollectorPolicy::record_concurrent_pause() {
914 if (_stop_world_start > 0.0) {
915 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
916 _all_yield_times_ms->add(yield_ms);
917 }
918 }
920 void G1CollectorPolicy::record_concurrent_pause_end() {
921 }
923 void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() {
924 _cur_CH_strong_roots_end_sec = os::elapsedTime();
925 _cur_CH_strong_roots_dur_ms =
926 (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0;
927 }
929 void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() {
930 _cur_G1_strong_roots_end_sec = os::elapsedTime();
931 _cur_G1_strong_roots_dur_ms =
932 (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0;
933 }
935 template<class T>
936 T sum_of(T* sum_arr, int start, int n, int N) {
937 T sum = (T)0;
938 for (int i = 0; i < n; i++) {
939 int j = (start + i) % N;
940 sum += sum_arr[j];
941 }
942 return sum;
943 }
945 void G1CollectorPolicy::print_par_stats (int level,
946 const char* str,
947 double* data,
948 bool summary) {
949 double min = data[0], max = data[0];
950 double total = 0.0;
951 int j;
952 for (j = 0; j < level; ++j)
953 gclog_or_tty->print(" ");
954 gclog_or_tty->print("[%s (ms):", str);
955 for (uint i = 0; i < ParallelGCThreads; ++i) {
956 double val = data[i];
957 if (val < min)
958 min = val;
959 if (val > max)
960 max = val;
961 total += val;
962 gclog_or_tty->print(" %3.1lf", val);
963 }
964 if (summary) {
965 gclog_or_tty->print_cr("");
966 double avg = total / (double) ParallelGCThreads;
967 gclog_or_tty->print(" ");
968 for (j = 0; j < level; ++j)
969 gclog_or_tty->print(" ");
970 gclog_or_tty->print("Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf",
971 avg, min, max);
972 }
973 gclog_or_tty->print_cr("]");
974 }
976 void G1CollectorPolicy::print_par_buffers (int level,
977 const char* str,
978 double* data,
979 bool summary) {
980 double min = data[0], max = data[0];
981 double total = 0.0;
982 int j;
983 for (j = 0; j < level; ++j)
984 gclog_or_tty->print(" ");
985 gclog_or_tty->print("[%s :", str);
986 for (uint i = 0; i < ParallelGCThreads; ++i) {
987 double val = data[i];
988 if (val < min)
989 min = val;
990 if (val > max)
991 max = val;
992 total += val;
993 gclog_or_tty->print(" %d", (int) val);
994 }
995 if (summary) {
996 gclog_or_tty->print_cr("");
997 double avg = total / (double) ParallelGCThreads;
998 gclog_or_tty->print(" ");
999 for (j = 0; j < level; ++j)
1000 gclog_or_tty->print(" ");
1001 gclog_or_tty->print("Sum: %d, Avg: %d, Min: %d, Max: %d",
1002 (int)total, (int)avg, (int)min, (int)max);
1003 }
1004 gclog_or_tty->print_cr("]");
1005 }
1007 void G1CollectorPolicy::print_stats (int level,
1008 const char* str,
1009 double value) {
1010 for (int j = 0; j < level; ++j)
1011 gclog_or_tty->print(" ");
1012 gclog_or_tty->print_cr("[%s: %5.1lf ms]", str, value);
1013 }
1015 void G1CollectorPolicy::print_stats (int level,
1016 const char* str,
1017 int value) {
1018 for (int j = 0; j < level; ++j)
1019 gclog_or_tty->print(" ");
1020 gclog_or_tty->print_cr("[%s: %d]", str, value);
1021 }
1023 double G1CollectorPolicy::avg_value (double* data) {
1024 if (ParallelGCThreads > 0) {
1025 double ret = 0.0;
1026 for (uint i = 0; i < ParallelGCThreads; ++i)
1027 ret += data[i];
1028 return ret / (double) ParallelGCThreads;
1029 } else {
1030 return data[0];
1031 }
1032 }
1034 double G1CollectorPolicy::max_value (double* data) {
1035 if (ParallelGCThreads > 0) {
1036 double ret = data[0];
1037 for (uint i = 1; i < ParallelGCThreads; ++i)
1038 if (data[i] > ret)
1039 ret = data[i];
1040 return ret;
1041 } else {
1042 return data[0];
1043 }
1044 }
1046 double G1CollectorPolicy::sum_of_values (double* data) {
1047 if (ParallelGCThreads > 0) {
1048 double sum = 0.0;
1049 for (uint i = 0; i < ParallelGCThreads; i++)
1050 sum += data[i];
1051 return sum;
1052 } else {
1053 return data[0];
1054 }
1055 }
1057 double G1CollectorPolicy::max_sum (double* data1,
1058 double* data2) {
1059 double ret = data1[0] + data2[0];
1061 if (ParallelGCThreads > 0) {
1062 for (uint i = 1; i < ParallelGCThreads; ++i) {
1063 double data = data1[i] + data2[i];
1064 if (data > ret)
1065 ret = data;
1066 }
1067 }
1068 return ret;
1069 }
1071 // Anything below that is considered to be zero
1072 #define MIN_TIMER_GRANULARITY 0.0000001
1074 void G1CollectorPolicy::record_collection_pause_end(bool abandoned) {
1075 double end_time_sec = os::elapsedTime();
1076 double elapsed_ms = _last_pause_time_ms;
1077 bool parallel = ParallelGCThreads > 0;
1078 double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0;
1079 size_t rs_size =
1080 _cur_collection_pause_used_regions_at_start - collection_set_size();
1081 size_t cur_used_bytes = _g1->used();
1082 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1083 bool last_pause_included_initial_mark = false;
1084 bool update_stats = !abandoned && !_g1->evacuation_failed();
1086 #ifndef PRODUCT
1087 if (G1YoungSurvRateVerbose) {
1088 gclog_or_tty->print_cr("");
1089 _short_lived_surv_rate_group->print();
1090 // do that for any other surv rate groups too
1091 }
1092 #endif // PRODUCT
1094 if (in_young_gc_mode()) {
1095 last_pause_included_initial_mark = during_initial_mark_pause();
1096 if (last_pause_included_initial_mark)
1097 record_concurrent_mark_init_end_pre(0.0);
1099 size_t min_used_targ =
1100 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
1103 if (!_g1->mark_in_progress() && !_last_full_young_gc) {
1104 assert(!last_pause_included_initial_mark, "invariant");
1105 if (cur_used_bytes > min_used_targ &&
1106 cur_used_bytes > _prev_collection_pause_used_at_end_bytes) {
1107 assert(!during_initial_mark_pause(), "we should not see this here");
1109 // Note: this might have already been set, if during the last
1110 // pause we decided to start a cycle but at the beginning of
1111 // this pause we decided to postpone it. That's OK.
1112 set_initiate_conc_mark_if_possible();
1113 }
1114 }
1116 _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
1117 }
1119 _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
1120 end_time_sec, false);
1122 guarantee(_cur_collection_pause_used_regions_at_start >=
1123 collection_set_size(),
1124 "Negative RS size?");
1126 // This assert is exempted when we're doing parallel collection pauses,
1127 // because the fragmentation caused by the parallel GC allocation buffers
1128 // can lead to more memory being used during collection than was used
1129 // before. Best leave this out until the fragmentation problem is fixed.
1130 // Pauses in which evacuation failed can also lead to negative
1131 // collections, since no space is reclaimed from a region containing an
1132 // object whose evacuation failed.
1133 // Further, we're now always doing parallel collection. But I'm still
1134 // leaving this here as a placeholder for a more precise assertion later.
1135 // (DLD, 10/05.)
1136 assert((true || parallel) // Always using GC LABs now.
1137 || _g1->evacuation_failed()
1138 || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
1139 "Negative collection");
1141 size_t freed_bytes =
1142 _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
1143 size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
1145 double survival_fraction =
1146 (double)surviving_bytes/
1147 (double)_collection_set_bytes_used_before;
1149 _n_pauses++;
1151 if (update_stats) {
1152 _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms);
1153 _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms);
1154 _recent_evac_times_ms->add(evac_ms);
1155 _recent_pause_times_ms->add(elapsed_ms);
1157 _recent_rs_sizes->add(rs_size);
1159 // We exempt parallel collection from this check because Alloc Buffer
1160 // fragmentation can produce negative collections. Same with evac
1161 // failure.
1162 // Further, we're now always doing parallel collection. But I'm still
1163 // leaving this here as a placeholder for a more precise assertion later.
1164 // (DLD, 10/05.
1165 assert((true || parallel)
1166 || _g1->evacuation_failed()
1167 || surviving_bytes <= _collection_set_bytes_used_before,
1168 "Or else negative collection!");
1169 _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
1170 _recent_CS_bytes_surviving->add(surviving_bytes);
1172 // this is where we update the allocation rate of the application
1173 double app_time_ms =
1174 (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
1175 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1176 // This usually happens due to the timer not having the required
1177 // granularity. Some Linuxes are the usual culprits.
1178 // We'll just set it to something (arbitrarily) small.
1179 app_time_ms = 1.0;
1180 }
1181 size_t regions_allocated =
1182 (_region_num_young - _prev_region_num_young) +
1183 (_region_num_tenured - _prev_region_num_tenured);
1184 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1185 _alloc_rate_ms_seq->add(alloc_rate_ms);
1186 _prev_region_num_young = _region_num_young;
1187 _prev_region_num_tenured = _region_num_tenured;
1189 double interval_ms =
1190 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1191 update_recent_gc_times(end_time_sec, elapsed_ms);
1192 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1193 if (recent_avg_pause_time_ratio() < 0.0 ||
1194 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1195 #ifndef PRODUCT
1196 // Dump info to allow post-facto debugging
1197 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1198 gclog_or_tty->print_cr("-------------------------------------------");
1199 gclog_or_tty->print_cr("Recent GC Times (ms):");
1200 _recent_gc_times_ms->dump();
1201 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1202 _recent_prev_end_times_for_all_gcs_sec->dump();
1203 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1204 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1205 // In debug mode, terminate the JVM if the user wants to debug at this point.
1206 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1207 #endif // !PRODUCT
1208 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1209 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1210 if (_recent_avg_pause_time_ratio < 0.0) {
1211 _recent_avg_pause_time_ratio = 0.0;
1212 } else {
1213 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1214 _recent_avg_pause_time_ratio = 1.0;
1215 }
1216 }
1217 }
1219 if (G1PolicyVerbose > 1) {
1220 gclog_or_tty->print_cr(" Recording collection pause(%d)", _n_pauses);
1221 }
1223 PauseSummary* summary;
1224 if (abandoned) {
1225 summary = _abandoned_summary;
1226 } else {
1227 summary = _summary;
1228 }
1230 double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
1231 double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
1232 double update_rs_time = avg_value(_par_last_update_rs_times_ms);
1233 double update_rs_processed_buffers =
1234 sum_of_values(_par_last_update_rs_processed_buffers);
1235 double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
1236 double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
1237 double termination_time = avg_value(_par_last_termination_times_ms);
1239 double parallel_other_time = _cur_collection_par_time_ms -
1240 (update_rs_time + ext_root_scan_time + mark_stack_scan_time +
1241 scan_rs_time + obj_copy_time + termination_time);
1242 if (update_stats) {
1243 MainBodySummary* body_summary = summary->main_body_summary();
1244 guarantee(body_summary != NULL, "should not be null!");
1246 if (_satb_drain_time_set)
1247 body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
1248 else
1249 body_summary->record_satb_drain_time_ms(0.0);
1250 body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
1251 body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
1252 body_summary->record_update_rs_time_ms(update_rs_time);
1253 body_summary->record_scan_rs_time_ms(scan_rs_time);
1254 body_summary->record_obj_copy_time_ms(obj_copy_time);
1255 if (parallel) {
1256 body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
1257 body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
1258 body_summary->record_termination_time_ms(termination_time);
1259 body_summary->record_parallel_other_time_ms(parallel_other_time);
1260 }
1261 body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
1262 }
1264 if (G1PolicyVerbose > 1) {
1265 gclog_or_tty->print_cr(" ET: %10.6f ms (avg: %10.6f ms)\n"
1266 " CH Strong: %10.6f ms (avg: %10.6f ms)\n"
1267 " G1 Strong: %10.6f ms (avg: %10.6f ms)\n"
1268 " Evac: %10.6f ms (avg: %10.6f ms)\n"
1269 " ET-RS: %10.6f ms (avg: %10.6f ms)\n"
1270 " |RS|: " SIZE_FORMAT,
1271 elapsed_ms, recent_avg_time_for_pauses_ms(),
1272 _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(),
1273 _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(),
1274 evac_ms, recent_avg_time_for_evac_ms(),
1275 scan_rs_time,
1276 recent_avg_time_for_pauses_ms() -
1277 recent_avg_time_for_G1_strong_ms(),
1278 rs_size);
1280 gclog_or_tty->print_cr(" Used at start: " SIZE_FORMAT"K"
1281 " At end " SIZE_FORMAT "K\n"
1282 " garbage : " SIZE_FORMAT "K"
1283 " of " SIZE_FORMAT "K\n"
1284 " survival : %6.2f%% (%6.2f%% avg)",
1285 _cur_collection_pause_used_at_start_bytes/K,
1286 _g1->used()/K, freed_bytes/K,
1287 _collection_set_bytes_used_before/K,
1288 survival_fraction*100.0,
1289 recent_avg_survival_fraction()*100.0);
1290 gclog_or_tty->print_cr(" Recent %% gc pause time: %6.2f",
1291 recent_avg_pause_time_ratio() * 100.0);
1292 }
1294 double other_time_ms = elapsed_ms;
1296 if (!abandoned) {
1297 if (_satb_drain_time_set)
1298 other_time_ms -= _cur_satb_drain_time_ms;
1300 if (parallel)
1301 other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
1302 else
1303 other_time_ms -=
1304 update_rs_time +
1305 ext_root_scan_time + mark_stack_scan_time +
1306 scan_rs_time + obj_copy_time;
1307 }
1309 if (PrintGCDetails) {
1310 gclog_or_tty->print_cr("%s%s, %1.8lf secs]",
1311 abandoned ? " (abandoned)" : "",
1312 (last_pause_included_initial_mark) ? " (initial-mark)" : "",
1313 elapsed_ms / 1000.0);
1315 if (!abandoned) {
1316 if (_satb_drain_time_set) {
1317 print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
1318 }
1319 if (_last_satb_drain_processed_buffers >= 0) {
1320 print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
1321 }
1322 if (parallel) {
1323 print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
1324 print_par_stats(2, "Update RS (Start)", _par_last_update_rs_start_times_ms, false);
1325 print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
1326 print_par_buffers(3, "Processed Buffers",
1327 _par_last_update_rs_processed_buffers, true);
1328 print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
1329 print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
1330 print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
1331 print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
1332 print_par_stats(2, "Termination", _par_last_termination_times_ms);
1333 print_stats(2, "Other", parallel_other_time);
1334 print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
1335 } else {
1336 print_stats(1, "Update RS", update_rs_time);
1337 print_stats(2, "Processed Buffers",
1338 (int)update_rs_processed_buffers);
1339 print_stats(1, "Ext Root Scanning", ext_root_scan_time);
1340 print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
1341 print_stats(1, "Scan RS", scan_rs_time);
1342 print_stats(1, "Object Copying", obj_copy_time);
1343 }
1344 }
1345 #ifndef PRODUCT
1346 print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
1347 print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
1348 print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
1349 print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
1350 if (_num_cc_clears > 0) {
1351 print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
1352 }
1353 #endif
1354 print_stats(1, "Other", other_time_ms);
1355 print_stats(2, "Choose CSet", _recorded_young_cset_choice_time_ms);
1357 for (int i = 0; i < _aux_num; ++i) {
1358 if (_cur_aux_times_set[i]) {
1359 char buffer[96];
1360 sprintf(buffer, "Aux%d", i);
1361 print_stats(1, buffer, _cur_aux_times_ms[i]);
1362 }
1363 }
1364 }
1365 if (PrintGCDetails)
1366 gclog_or_tty->print(" [");
1367 if (PrintGC || PrintGCDetails)
1368 _g1->print_size_transition(gclog_or_tty,
1369 _cur_collection_pause_used_at_start_bytes,
1370 _g1->used(), _g1->capacity());
1371 if (PrintGCDetails)
1372 gclog_or_tty->print_cr("]");
1374 _all_pause_times_ms->add(elapsed_ms);
1375 if (update_stats) {
1376 summary->record_total_time_ms(elapsed_ms);
1377 summary->record_other_time_ms(other_time_ms);
1378 }
1379 for (int i = 0; i < _aux_num; ++i)
1380 if (_cur_aux_times_set[i])
1381 _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
1383 // Reset marks-between-pauses counter.
1384 _n_marks_since_last_pause = 0;
1386 // Update the efficiency-since-mark vars.
1387 double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
1388 if (elapsed_ms < MIN_TIMER_GRANULARITY) {
1389 // This usually happens due to the timer not having the required
1390 // granularity. Some Linuxes are the usual culprits.
1391 // We'll just set it to something (arbitrarily) small.
1392 proc_ms = 1.0;
1393 }
1394 double cur_efficiency = (double) freed_bytes / proc_ms;
1396 bool new_in_marking_window = _in_marking_window;
1397 bool new_in_marking_window_im = false;
1398 if (during_initial_mark_pause()) {
1399 new_in_marking_window = true;
1400 new_in_marking_window_im = true;
1401 }
1403 if (in_young_gc_mode()) {
1404 if (_last_full_young_gc) {
1405 set_full_young_gcs(false);
1406 _last_full_young_gc = false;
1407 }
1409 if ( !_last_young_gc_full ) {
1410 if ( _should_revert_to_full_young_gcs ||
1411 _known_garbage_ratio < 0.05 ||
1412 (adaptive_young_list_length() &&
1413 (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) {
1414 set_full_young_gcs(true);
1415 }
1416 }
1417 _should_revert_to_full_young_gcs = false;
1419 if (_last_young_gc_full && !_during_marking)
1420 _young_gc_eff_seq->add(cur_efficiency);
1421 }
1423 _short_lived_surv_rate_group->start_adding_regions();
1424 // do that for any other surv rate groupsx
1426 // <NEW PREDICTION>
1428 if (update_stats) {
1429 double pause_time_ms = elapsed_ms;
1431 size_t diff = 0;
1432 if (_max_pending_cards >= _pending_cards)
1433 diff = _max_pending_cards - _pending_cards;
1434 _pending_card_diff_seq->add((double) diff);
1436 double cost_per_card_ms = 0.0;
1437 if (_pending_cards > 0) {
1438 cost_per_card_ms = update_rs_time / (double) _pending_cards;
1439 _cost_per_card_ms_seq->add(cost_per_card_ms);
1440 }
1442 size_t cards_scanned = _g1->cards_scanned();
1444 double cost_per_entry_ms = 0.0;
1445 if (cards_scanned > 10) {
1446 cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
1447 if (_last_young_gc_full)
1448 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1449 else
1450 _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1451 }
1453 if (_max_rs_lengths > 0) {
1454 double cards_per_entry_ratio =
1455 (double) cards_scanned / (double) _max_rs_lengths;
1456 if (_last_young_gc_full)
1457 _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1458 else
1459 _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1460 }
1462 size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1463 if (rs_length_diff >= 0)
1464 _rs_length_diff_seq->add((double) rs_length_diff);
1466 size_t copied_bytes = surviving_bytes;
1467 double cost_per_byte_ms = 0.0;
1468 if (copied_bytes > 0) {
1469 cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
1470 if (_in_marking_window)
1471 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1472 else
1473 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1474 }
1476 double all_other_time_ms = pause_time_ms -
1477 (update_rs_time + scan_rs_time + obj_copy_time +
1478 _mark_closure_time_ms + termination_time);
1480 double young_other_time_ms = 0.0;
1481 if (_recorded_young_regions > 0) {
1482 young_other_time_ms =
1483 _recorded_young_cset_choice_time_ms +
1484 _recorded_young_free_cset_time_ms;
1485 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1486 (double) _recorded_young_regions);
1487 }
1488 double non_young_other_time_ms = 0.0;
1489 if (_recorded_non_young_regions > 0) {
1490 non_young_other_time_ms =
1491 _recorded_non_young_cset_choice_time_ms +
1492 _recorded_non_young_free_cset_time_ms;
1494 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1495 (double) _recorded_non_young_regions);
1496 }
1498 double constant_other_time_ms = all_other_time_ms -
1499 (young_other_time_ms + non_young_other_time_ms);
1500 _constant_other_time_ms_seq->add(constant_other_time_ms);
1502 double survival_ratio = 0.0;
1503 if (_bytes_in_collection_set_before_gc > 0) {
1504 survival_ratio = (double) bytes_in_to_space_during_gc() /
1505 (double) _bytes_in_collection_set_before_gc;
1506 }
1508 _pending_cards_seq->add((double) _pending_cards);
1509 _scanned_cards_seq->add((double) cards_scanned);
1510 _rs_lengths_seq->add((double) _max_rs_lengths);
1512 double expensive_region_limit_ms =
1513 (double) MaxGCPauseMillis - predict_constant_other_time_ms();
1514 if (expensive_region_limit_ms < 0.0) {
1515 // this means that the other time was predicted to be longer than
1516 // than the max pause time
1517 expensive_region_limit_ms = (double) MaxGCPauseMillis;
1518 }
1519 _expensive_region_limit_ms = expensive_region_limit_ms;
1521 if (PREDICTIONS_VERBOSE) {
1522 gclog_or_tty->print_cr("");
1523 gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
1524 "REGIONS %d %d %d "
1525 "PENDING_CARDS %d %d "
1526 "CARDS_SCANNED %d %d "
1527 "RS_LENGTHS %d %d "
1528 "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
1529 "SURVIVAL_RATIO %1.6lf %1.6lf "
1530 "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
1531 "OTHER_YOUNG %1.6lf %1.6lf "
1532 "OTHER_NON_YOUNG %1.6lf %1.6lf "
1533 "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
1534 "ELAPSED %1.6lf %1.6lf ",
1535 _cur_collection_start_sec,
1536 (!_last_young_gc_full) ? 2 :
1537 (last_pause_included_initial_mark) ? 1 : 0,
1538 _recorded_region_num,
1539 _recorded_young_regions,
1540 _recorded_non_young_regions,
1541 _predicted_pending_cards, _pending_cards,
1542 _predicted_cards_scanned, cards_scanned,
1543 _predicted_rs_lengths, _max_rs_lengths,
1544 _predicted_rs_update_time_ms, update_rs_time,
1545 _predicted_rs_scan_time_ms, scan_rs_time,
1546 _predicted_survival_ratio, survival_ratio,
1547 _predicted_object_copy_time_ms, obj_copy_time,
1548 _predicted_constant_other_time_ms, constant_other_time_ms,
1549 _predicted_young_other_time_ms, young_other_time_ms,
1550 _predicted_non_young_other_time_ms,
1551 non_young_other_time_ms,
1552 _vtime_diff_ms, termination_time,
1553 _predicted_pause_time_ms, elapsed_ms);
1554 }
1556 if (G1PolicyVerbose > 0) {
1557 gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
1558 _predicted_pause_time_ms,
1559 (_within_target) ? "within" : "outside",
1560 elapsed_ms);
1561 }
1563 }
1565 _in_marking_window = new_in_marking_window;
1566 _in_marking_window_im = new_in_marking_window_im;
1567 _free_regions_at_end_of_collection = _g1->free_regions();
1568 calculate_young_list_min_length();
1569 calculate_young_list_target_length();
1571 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1572 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1573 adjust_concurrent_refinement(update_rs_time, update_rs_processed_buffers, update_rs_time_goal_ms);
1574 // </NEW PREDICTION>
1576 _target_pause_time_ms = -1.0;
1577 }
1579 // <NEW PREDICTION>
1581 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1582 double update_rs_processed_buffers,
1583 double goal_ms) {
1584 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1585 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1587 if (G1UseAdaptiveConcRefinement) {
1588 const int k_gy = 3, k_gr = 6;
1589 const double inc_k = 1.1, dec_k = 0.9;
1591 int g = cg1r->green_zone();
1592 if (update_rs_time > goal_ms) {
1593 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1594 } else {
1595 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1596 g = (int)MAX2(g * inc_k, g + 1.0);
1597 }
1598 }
1599 // Change the refinement threads params
1600 cg1r->set_green_zone(g);
1601 cg1r->set_yellow_zone(g * k_gy);
1602 cg1r->set_red_zone(g * k_gr);
1603 cg1r->reinitialize_threads();
1605 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1606 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1607 cg1r->yellow_zone());
1608 // Change the barrier params
1609 dcqs.set_process_completed_threshold(processing_threshold);
1610 dcqs.set_max_completed_queue(cg1r->red_zone());
1611 }
1613 int curr_queue_size = dcqs.completed_buffers_num();
1614 if (curr_queue_size >= cg1r->yellow_zone()) {
1615 dcqs.set_completed_queue_padding(curr_queue_size);
1616 } else {
1617 dcqs.set_completed_queue_padding(0);
1618 }
1619 dcqs.notify_if_necessary();
1620 }
1622 double
1623 G1CollectorPolicy::
1624 predict_young_collection_elapsed_time_ms(size_t adjustment) {
1625 guarantee( adjustment == 0 || adjustment == 1, "invariant" );
1627 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1628 size_t young_num = g1h->young_list()->length();
1629 if (young_num == 0)
1630 return 0.0;
1632 young_num += adjustment;
1633 size_t pending_cards = predict_pending_cards();
1634 size_t rs_lengths = g1h->young_list()->sampled_rs_lengths() +
1635 predict_rs_length_diff();
1636 size_t card_num;
1637 if (full_young_gcs())
1638 card_num = predict_young_card_num(rs_lengths);
1639 else
1640 card_num = predict_non_young_card_num(rs_lengths);
1641 size_t young_byte_size = young_num * HeapRegion::GrainBytes;
1642 double accum_yg_surv_rate =
1643 _short_lived_surv_rate_group->accum_surv_rate(adjustment);
1645 size_t bytes_to_copy =
1646 (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
1648 return
1649 predict_rs_update_time_ms(pending_cards) +
1650 predict_rs_scan_time_ms(card_num) +
1651 predict_object_copy_time_ms(bytes_to_copy) +
1652 predict_young_other_time_ms(young_num) +
1653 predict_constant_other_time_ms();
1654 }
1656 double
1657 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1658 size_t rs_length = predict_rs_length_diff();
1659 size_t card_num;
1660 if (full_young_gcs())
1661 card_num = predict_young_card_num(rs_length);
1662 else
1663 card_num = predict_non_young_card_num(rs_length);
1664 return predict_base_elapsed_time_ms(pending_cards, card_num);
1665 }
1667 double
1668 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1669 size_t scanned_cards) {
1670 return
1671 predict_rs_update_time_ms(pending_cards) +
1672 predict_rs_scan_time_ms(scanned_cards) +
1673 predict_constant_other_time_ms();
1674 }
1676 double
1677 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1678 bool young) {
1679 size_t rs_length = hr->rem_set()->occupied();
1680 size_t card_num;
1681 if (full_young_gcs())
1682 card_num = predict_young_card_num(rs_length);
1683 else
1684 card_num = predict_non_young_card_num(rs_length);
1685 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1687 double region_elapsed_time_ms =
1688 predict_rs_scan_time_ms(card_num) +
1689 predict_object_copy_time_ms(bytes_to_copy);
1691 if (young)
1692 region_elapsed_time_ms += predict_young_other_time_ms(1);
1693 else
1694 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1696 return region_elapsed_time_ms;
1697 }
1699 size_t
1700 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1701 size_t bytes_to_copy;
1702 if (hr->is_marked())
1703 bytes_to_copy = hr->max_live_bytes();
1704 else {
1705 guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
1706 "invariant" );
1707 int age = hr->age_in_surv_rate_group();
1708 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1709 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1710 }
1712 return bytes_to_copy;
1713 }
1715 void
1716 G1CollectorPolicy::start_recording_regions() {
1717 _recorded_rs_lengths = 0;
1718 _recorded_young_regions = 0;
1719 _recorded_non_young_regions = 0;
1721 #if PREDICTIONS_VERBOSE
1722 _recorded_marked_bytes = 0;
1723 _recorded_young_bytes = 0;
1724 _predicted_bytes_to_copy = 0;
1725 _predicted_rs_lengths = 0;
1726 _predicted_cards_scanned = 0;
1727 #endif // PREDICTIONS_VERBOSE
1728 }
1730 void
1731 G1CollectorPolicy::record_cset_region_info(HeapRegion* hr, bool young) {
1732 #if PREDICTIONS_VERBOSE
1733 if (!young) {
1734 _recorded_marked_bytes += hr->max_live_bytes();
1735 }
1736 _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
1737 #endif // PREDICTIONS_VERBOSE
1739 size_t rs_length = hr->rem_set()->occupied();
1740 _recorded_rs_lengths += rs_length;
1741 }
1743 void
1744 G1CollectorPolicy::record_non_young_cset_region(HeapRegion* hr) {
1745 assert(!hr->is_young(), "should not call this");
1746 ++_recorded_non_young_regions;
1747 record_cset_region_info(hr, false);
1748 }
1750 void
1751 G1CollectorPolicy::set_recorded_young_regions(size_t n_regions) {
1752 _recorded_young_regions = n_regions;
1753 }
1755 void G1CollectorPolicy::set_recorded_young_bytes(size_t bytes) {
1756 #if PREDICTIONS_VERBOSE
1757 _recorded_young_bytes = bytes;
1758 #endif // PREDICTIONS_VERBOSE
1759 }
1761 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1762 _recorded_rs_lengths = rs_lengths;
1763 }
1765 void G1CollectorPolicy::set_predicted_bytes_to_copy(size_t bytes) {
1766 _predicted_bytes_to_copy = bytes;
1767 }
1769 void
1770 G1CollectorPolicy::end_recording_regions() {
1771 // The _predicted_pause_time_ms field is referenced in code
1772 // not under PREDICTIONS_VERBOSE. Let's initialize it.
1773 _predicted_pause_time_ms = -1.0;
1775 #if PREDICTIONS_VERBOSE
1776 _predicted_pending_cards = predict_pending_cards();
1777 _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
1778 if (full_young_gcs())
1779 _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
1780 else
1781 _predicted_cards_scanned +=
1782 predict_non_young_card_num(_predicted_rs_lengths);
1783 _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
1785 _predicted_rs_update_time_ms =
1786 predict_rs_update_time_ms(_g1->pending_card_num());
1787 _predicted_rs_scan_time_ms =
1788 predict_rs_scan_time_ms(_predicted_cards_scanned);
1789 _predicted_object_copy_time_ms =
1790 predict_object_copy_time_ms(_predicted_bytes_to_copy);
1791 _predicted_constant_other_time_ms =
1792 predict_constant_other_time_ms();
1793 _predicted_young_other_time_ms =
1794 predict_young_other_time_ms(_recorded_young_regions);
1795 _predicted_non_young_other_time_ms =
1796 predict_non_young_other_time_ms(_recorded_non_young_regions);
1798 _predicted_pause_time_ms =
1799 _predicted_rs_update_time_ms +
1800 _predicted_rs_scan_time_ms +
1801 _predicted_object_copy_time_ms +
1802 _predicted_constant_other_time_ms +
1803 _predicted_young_other_time_ms +
1804 _predicted_non_young_other_time_ms;
1805 #endif // PREDICTIONS_VERBOSE
1806 }
1808 void G1CollectorPolicy::check_if_region_is_too_expensive(double
1809 predicted_time_ms) {
1810 // I don't think we need to do this when in young GC mode since
1811 // marking will be initiated next time we hit the soft limit anyway...
1812 if (predicted_time_ms > _expensive_region_limit_ms) {
1813 if (!in_young_gc_mode()) {
1814 set_full_young_gcs(true);
1815 // We might want to do something different here. However,
1816 // right now we don't support the non-generational G1 mode
1817 // (and in fact we are planning to remove the associated code,
1818 // see CR 6814390). So, let's leave it as is and this will be
1819 // removed some time in the future
1820 ShouldNotReachHere();
1821 set_during_initial_mark_pause();
1822 } else
1823 // no point in doing another partial one
1824 _should_revert_to_full_young_gcs = true;
1825 }
1826 }
1828 // </NEW PREDICTION>
1831 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
1832 double elapsed_ms) {
1833 _recent_gc_times_ms->add(elapsed_ms);
1834 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
1835 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
1836 }
1838 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
1839 if (_recent_pause_times_ms->num() == 0) return (double) MaxGCPauseMillis;
1840 else return _recent_pause_times_ms->avg();
1841 }
1843 double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() {
1844 if (_recent_CH_strong_roots_times_ms->num() == 0)
1845 return (double)MaxGCPauseMillis/3.0;
1846 else return _recent_CH_strong_roots_times_ms->avg();
1847 }
1849 double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() {
1850 if (_recent_G1_strong_roots_times_ms->num() == 0)
1851 return (double)MaxGCPauseMillis/3.0;
1852 else return _recent_G1_strong_roots_times_ms->avg();
1853 }
1855 double G1CollectorPolicy::recent_avg_time_for_evac_ms() {
1856 if (_recent_evac_times_ms->num() == 0) return (double)MaxGCPauseMillis/3.0;
1857 else return _recent_evac_times_ms->avg();
1858 }
1860 int G1CollectorPolicy::number_of_recent_gcs() {
1861 assert(_recent_CH_strong_roots_times_ms->num() ==
1862 _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync");
1863 assert(_recent_G1_strong_roots_times_ms->num() ==
1864 _recent_evac_times_ms->num(), "Sequence out of sync");
1865 assert(_recent_evac_times_ms->num() ==
1866 _recent_pause_times_ms->num(), "Sequence out of sync");
1867 assert(_recent_pause_times_ms->num() ==
1868 _recent_CS_bytes_used_before->num(), "Sequence out of sync");
1869 assert(_recent_CS_bytes_used_before->num() ==
1870 _recent_CS_bytes_surviving->num(), "Sequence out of sync");
1871 return _recent_pause_times_ms->num();
1872 }
1874 double G1CollectorPolicy::recent_avg_survival_fraction() {
1875 return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
1876 _recent_CS_bytes_used_before);
1877 }
1879 double G1CollectorPolicy::last_survival_fraction() {
1880 return last_survival_fraction_work(_recent_CS_bytes_surviving,
1881 _recent_CS_bytes_used_before);
1882 }
1884 double
1885 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
1886 TruncatedSeq* before) {
1887 assert(surviving->num() == before->num(), "Sequence out of sync");
1888 if (before->sum() > 0.0) {
1889 double recent_survival_rate = surviving->sum() / before->sum();
1890 // We exempt parallel collection from this check because Alloc Buffer
1891 // fragmentation can produce negative collections.
1892 // Further, we're now always doing parallel collection. But I'm still
1893 // leaving this here as a placeholder for a more precise assertion later.
1894 // (DLD, 10/05.)
1895 assert((true || ParallelGCThreads > 0) ||
1896 _g1->evacuation_failed() ||
1897 recent_survival_rate <= 1.0, "Or bad frac");
1898 return recent_survival_rate;
1899 } else {
1900 return 1.0; // Be conservative.
1901 }
1902 }
1904 double
1905 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
1906 TruncatedSeq* before) {
1907 assert(surviving->num() == before->num(), "Sequence out of sync");
1908 if (surviving->num() > 0 && before->last() > 0.0) {
1909 double last_survival_rate = surviving->last() / before->last();
1910 // We exempt parallel collection from this check because Alloc Buffer
1911 // fragmentation can produce negative collections.
1912 // Further, we're now always doing parallel collection. But I'm still
1913 // leaving this here as a placeholder for a more precise assertion later.
1914 // (DLD, 10/05.)
1915 assert((true || ParallelGCThreads > 0) ||
1916 last_survival_rate <= 1.0, "Or bad frac");
1917 return last_survival_rate;
1918 } else {
1919 return 1.0;
1920 }
1921 }
1923 static const int survival_min_obs = 5;
1924 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
1925 static const double min_survival_rate = 0.1;
1927 double
1928 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
1929 double latest) {
1930 double res = avg;
1931 if (number_of_recent_gcs() < survival_min_obs) {
1932 res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
1933 }
1934 res = MAX2(res, latest);
1935 res = MAX2(res, min_survival_rate);
1936 // In the parallel case, LAB fragmentation can produce "negative
1937 // collections"; so can evac failure. Cap at 1.0
1938 res = MIN2(res, 1.0);
1939 return res;
1940 }
1942 size_t G1CollectorPolicy::expansion_amount() {
1943 if ((recent_avg_pause_time_ratio() * 100.0) > _gc_overhead_perc) {
1944 // We will double the existing space, or take
1945 // G1ExpandByPercentOfAvailable % of the available expansion
1946 // space, whichever is smaller, bounded below by a minimum
1947 // expansion (unless that's all that's left.)
1948 const size_t min_expand_bytes = 1*M;
1949 size_t reserved_bytes = _g1->g1_reserved_obj_bytes();
1950 size_t committed_bytes = _g1->capacity();
1951 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
1952 size_t expand_bytes;
1953 size_t expand_bytes_via_pct =
1954 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
1955 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
1956 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
1957 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
1958 if (G1PolicyVerbose > 1) {
1959 gclog_or_tty->print("Decided to expand: ratio = %5.2f, "
1960 "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n"
1961 " Answer = %d.\n",
1962 recent_avg_pause_time_ratio(),
1963 byte_size_in_proper_unit(committed_bytes),
1964 proper_unit_for_byte_size(committed_bytes),
1965 byte_size_in_proper_unit(uncommitted_bytes),
1966 proper_unit_for_byte_size(uncommitted_bytes),
1967 byte_size_in_proper_unit(expand_bytes_via_pct),
1968 proper_unit_for_byte_size(expand_bytes_via_pct),
1969 byte_size_in_proper_unit(expand_bytes),
1970 proper_unit_for_byte_size(expand_bytes));
1971 }
1972 return expand_bytes;
1973 } else {
1974 return 0;
1975 }
1976 }
1978 void G1CollectorPolicy::note_start_of_mark_thread() {
1979 _mark_thread_startup_sec = os::elapsedTime();
1980 }
1982 class CountCSClosure: public HeapRegionClosure {
1983 G1CollectorPolicy* _g1_policy;
1984 public:
1985 CountCSClosure(G1CollectorPolicy* g1_policy) :
1986 _g1_policy(g1_policy) {}
1987 bool doHeapRegion(HeapRegion* r) {
1988 _g1_policy->_bytes_in_collection_set_before_gc += r->used();
1989 return false;
1990 }
1991 };
1993 void G1CollectorPolicy::count_CS_bytes_used() {
1994 CountCSClosure cs_closure(this);
1995 _g1->collection_set_iterate(&cs_closure);
1996 }
1998 static void print_indent(int level) {
1999 for (int j = 0; j < level+1; ++j)
2000 gclog_or_tty->print(" ");
2001 }
2003 void G1CollectorPolicy::print_summary (int level,
2004 const char* str,
2005 NumberSeq* seq) const {
2006 double sum = seq->sum();
2007 print_indent(level);
2008 gclog_or_tty->print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
2009 str, sum / 1000.0, seq->avg());
2010 }
2012 void G1CollectorPolicy::print_summary_sd (int level,
2013 const char* str,
2014 NumberSeq* seq) const {
2015 print_summary(level, str, seq);
2016 print_indent(level + 5);
2017 gclog_or_tty->print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2018 seq->num(), seq->sd(), seq->maximum());
2019 }
2021 void G1CollectorPolicy::check_other_times(int level,
2022 NumberSeq* other_times_ms,
2023 NumberSeq* calc_other_times_ms) const {
2024 bool should_print = false;
2026 double max_sum = MAX2(fabs(other_times_ms->sum()),
2027 fabs(calc_other_times_ms->sum()));
2028 double min_sum = MIN2(fabs(other_times_ms->sum()),
2029 fabs(calc_other_times_ms->sum()));
2030 double sum_ratio = max_sum / min_sum;
2031 if (sum_ratio > 1.1) {
2032 should_print = true;
2033 print_indent(level + 1);
2034 gclog_or_tty->print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
2035 }
2037 double max_avg = MAX2(fabs(other_times_ms->avg()),
2038 fabs(calc_other_times_ms->avg()));
2039 double min_avg = MIN2(fabs(other_times_ms->avg()),
2040 fabs(calc_other_times_ms->avg()));
2041 double avg_ratio = max_avg / min_avg;
2042 if (avg_ratio > 1.1) {
2043 should_print = true;
2044 print_indent(level + 1);
2045 gclog_or_tty->print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
2046 }
2048 if (other_times_ms->sum() < -0.01) {
2049 print_indent(level + 1);
2050 gclog_or_tty->print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
2051 }
2053 if (other_times_ms->avg() < -0.01) {
2054 print_indent(level + 1);
2055 gclog_or_tty->print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
2056 }
2058 if (calc_other_times_ms->sum() < -0.01) {
2059 should_print = true;
2060 print_indent(level + 1);
2061 gclog_or_tty->print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
2062 }
2064 if (calc_other_times_ms->avg() < -0.01) {
2065 should_print = true;
2066 print_indent(level + 1);
2067 gclog_or_tty->print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
2068 }
2070 if (should_print)
2071 print_summary(level, "Other(Calc)", calc_other_times_ms);
2072 }
2074 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
2075 bool parallel = ParallelGCThreads > 0;
2076 MainBodySummary* body_summary = summary->main_body_summary();
2077 if (summary->get_total_seq()->num() > 0) {
2078 print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
2079 if (body_summary != NULL) {
2080 print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
2081 if (parallel) {
2082 print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
2083 print_summary(2, "Update RS", body_summary->get_update_rs_seq());
2084 print_summary(2, "Ext Root Scanning",
2085 body_summary->get_ext_root_scan_seq());
2086 print_summary(2, "Mark Stack Scanning",
2087 body_summary->get_mark_stack_scan_seq());
2088 print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
2089 print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
2090 print_summary(2, "Termination", body_summary->get_termination_seq());
2091 print_summary(2, "Other", body_summary->get_parallel_other_seq());
2092 {
2093 NumberSeq* other_parts[] = {
2094 body_summary->get_update_rs_seq(),
2095 body_summary->get_ext_root_scan_seq(),
2096 body_summary->get_mark_stack_scan_seq(),
2097 body_summary->get_scan_rs_seq(),
2098 body_summary->get_obj_copy_seq(),
2099 body_summary->get_termination_seq()
2100 };
2101 NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
2102 7, other_parts);
2103 check_other_times(2, body_summary->get_parallel_other_seq(),
2104 &calc_other_times_ms);
2105 }
2106 print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
2107 print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
2108 } else {
2109 print_summary(1, "Update RS", body_summary->get_update_rs_seq());
2110 print_summary(1, "Ext Root Scanning",
2111 body_summary->get_ext_root_scan_seq());
2112 print_summary(1, "Mark Stack Scanning",
2113 body_summary->get_mark_stack_scan_seq());
2114 print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
2115 print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
2116 }
2117 }
2118 print_summary(1, "Other", summary->get_other_seq());
2119 {
2120 NumberSeq calc_other_times_ms;
2121 if (body_summary != NULL) {
2122 // not abandoned
2123 if (parallel) {
2124 // parallel
2125 NumberSeq* other_parts[] = {
2126 body_summary->get_satb_drain_seq(),
2127 body_summary->get_parallel_seq(),
2128 body_summary->get_clear_ct_seq()
2129 };
2130 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2131 3, other_parts);
2132 } else {
2133 // serial
2134 NumberSeq* other_parts[] = {
2135 body_summary->get_satb_drain_seq(),
2136 body_summary->get_update_rs_seq(),
2137 body_summary->get_ext_root_scan_seq(),
2138 body_summary->get_mark_stack_scan_seq(),
2139 body_summary->get_scan_rs_seq(),
2140 body_summary->get_obj_copy_seq()
2141 };
2142 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2143 7, other_parts);
2144 }
2145 } else {
2146 // abandoned
2147 calc_other_times_ms = NumberSeq();
2148 }
2149 check_other_times(1, summary->get_other_seq(), &calc_other_times_ms);
2150 }
2151 } else {
2152 print_indent(0);
2153 gclog_or_tty->print_cr("none");
2154 }
2155 gclog_or_tty->print_cr("");
2156 }
2158 void
2159 G1CollectorPolicy::print_abandoned_summary(PauseSummary* summary) const {
2160 bool printed = false;
2161 if (summary->get_total_seq()->num() > 0) {
2162 printed = true;
2163 print_summary(summary);
2164 }
2165 if (!printed) {
2166 print_indent(0);
2167 gclog_or_tty->print_cr("none");
2168 gclog_or_tty->print_cr("");
2169 }
2170 }
2172 void G1CollectorPolicy::print_tracing_info() const {
2173 if (TraceGen0Time) {
2174 gclog_or_tty->print_cr("ALL PAUSES");
2175 print_summary_sd(0, "Total", _all_pause_times_ms);
2176 gclog_or_tty->print_cr("");
2177 gclog_or_tty->print_cr("");
2178 gclog_or_tty->print_cr(" Full Young GC Pauses: %8d", _full_young_pause_num);
2179 gclog_or_tty->print_cr(" Partial Young GC Pauses: %8d", _partial_young_pause_num);
2180 gclog_or_tty->print_cr("");
2182 gclog_or_tty->print_cr("EVACUATION PAUSES");
2183 print_summary(_summary);
2185 gclog_or_tty->print_cr("ABANDONED PAUSES");
2186 print_abandoned_summary(_abandoned_summary);
2188 gclog_or_tty->print_cr("MISC");
2189 print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
2190 print_summary_sd(0, "Yields", _all_yield_times_ms);
2191 for (int i = 0; i < _aux_num; ++i) {
2192 if (_all_aux_times_ms[i].num() > 0) {
2193 char buffer[96];
2194 sprintf(buffer, "Aux%d", i);
2195 print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
2196 }
2197 }
2199 size_t all_region_num = _region_num_young + _region_num_tenured;
2200 gclog_or_tty->print_cr(" New Regions %8d, Young %8d (%6.2lf%%), "
2201 "Tenured %8d (%6.2lf%%)",
2202 all_region_num,
2203 _region_num_young,
2204 (double) _region_num_young / (double) all_region_num * 100.0,
2205 _region_num_tenured,
2206 (double) _region_num_tenured / (double) all_region_num * 100.0);
2207 }
2208 if (TraceGen1Time) {
2209 if (_all_full_gc_times_ms->num() > 0) {
2210 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2211 _all_full_gc_times_ms->num(),
2212 _all_full_gc_times_ms->sum() / 1000.0);
2213 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
2214 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2215 _all_full_gc_times_ms->sd(),
2216 _all_full_gc_times_ms->maximum());
2217 }
2218 }
2219 }
2221 void G1CollectorPolicy::print_yg_surv_rate_info() const {
2222 #ifndef PRODUCT
2223 _short_lived_surv_rate_group->print_surv_rate_summary();
2224 // add this call for any other surv rate groups
2225 #endif // PRODUCT
2226 }
2228 bool
2229 G1CollectorPolicy::should_add_next_region_to_young_list() {
2230 assert(in_young_gc_mode(), "should be in young GC mode");
2231 bool ret;
2232 size_t young_list_length = _g1->young_list()->length();
2233 size_t young_list_max_length = _young_list_target_length;
2234 if (G1FixedEdenSize) {
2235 young_list_max_length -= _max_survivor_regions;
2236 }
2237 if (young_list_length < young_list_max_length) {
2238 ret = true;
2239 ++_region_num_young;
2240 } else {
2241 ret = false;
2242 ++_region_num_tenured;
2243 }
2245 return ret;
2246 }
2248 #ifndef PRODUCT
2249 // for debugging, bit of a hack...
2250 static char*
2251 region_num_to_mbs(int length) {
2252 static char buffer[64];
2253 double bytes = (double) (length * HeapRegion::GrainBytes);
2254 double mbs = bytes / (double) (1024 * 1024);
2255 sprintf(buffer, "%7.2lfMB", mbs);
2256 return buffer;
2257 }
2258 #endif // PRODUCT
2260 size_t G1CollectorPolicy::max_regions(int purpose) {
2261 switch (purpose) {
2262 case GCAllocForSurvived:
2263 return _max_survivor_regions;
2264 case GCAllocForTenured:
2265 return REGIONS_UNLIMITED;
2266 default:
2267 ShouldNotReachHere();
2268 return REGIONS_UNLIMITED;
2269 };
2270 }
2272 // Calculates survivor space parameters.
2273 void G1CollectorPolicy::calculate_survivors_policy()
2274 {
2275 if (G1FixedSurvivorSpaceSize == 0) {
2276 _max_survivor_regions = _young_list_target_length / SurvivorRatio;
2277 } else {
2278 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
2279 }
2281 if (G1FixedTenuringThreshold) {
2282 _tenuring_threshold = MaxTenuringThreshold;
2283 } else {
2284 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
2285 HeapRegion::GrainWords * _max_survivor_regions);
2286 }
2287 }
2289 bool
2290 G1CollectorPolicy_BestRegionsFirst::should_do_collection_pause(size_t
2291 word_size) {
2292 assert(_g1->regions_accounted_for(), "Region leakage!");
2293 double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
2295 size_t young_list_length = _g1->young_list()->length();
2296 size_t young_list_max_length = _young_list_target_length;
2297 if (G1FixedEdenSize) {
2298 young_list_max_length -= _max_survivor_regions;
2299 }
2300 bool reached_target_length = young_list_length >= young_list_max_length;
2302 if (in_young_gc_mode()) {
2303 if (reached_target_length) {
2304 assert( young_list_length > 0 && _g1->young_list()->length() > 0,
2305 "invariant" );
2306 _target_pause_time_ms = max_pause_time_ms;
2307 return true;
2308 }
2309 } else {
2310 guarantee( false, "should not reach here" );
2311 }
2313 return false;
2314 }
2316 #ifndef PRODUCT
2317 class HRSortIndexIsOKClosure: public HeapRegionClosure {
2318 CollectionSetChooser* _chooser;
2319 public:
2320 HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
2321 _chooser(chooser) {}
2323 bool doHeapRegion(HeapRegion* r) {
2324 if (!r->continuesHumongous()) {
2325 assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
2326 }
2327 return false;
2328 }
2329 };
2331 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
2332 HRSortIndexIsOKClosure cl(_collectionSetChooser);
2333 _g1->heap_region_iterate(&cl);
2334 return true;
2335 }
2336 #endif
2338 void
2339 G1CollectorPolicy::decide_on_conc_mark_initiation() {
2340 // We are about to decide on whether this pause will be an
2341 // initial-mark pause.
2343 // First, during_initial_mark_pause() should not be already set. We
2344 // will set it here if we have to. However, it should be cleared by
2345 // the end of the pause (it's only set for the duration of an
2346 // initial-mark pause).
2347 assert(!during_initial_mark_pause(), "pre-condition");
2349 if (initiate_conc_mark_if_possible()) {
2350 // We had noticed on a previous pause that the heap occupancy has
2351 // gone over the initiating threshold and we should start a
2352 // concurrent marking cycle. So we might initiate one.
2354 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
2355 if (!during_cycle) {
2356 // The concurrent marking thread is not "during a cycle", i.e.,
2357 // it has completed the last one. So we can go ahead and
2358 // initiate a new cycle.
2360 set_during_initial_mark_pause();
2362 // And we can now clear initiate_conc_mark_if_possible() as
2363 // we've already acted on it.
2364 clear_initiate_conc_mark_if_possible();
2365 } else {
2366 // The concurrent marking thread is still finishing up the
2367 // previous cycle. If we start one right now the two cycles
2368 // overlap. In particular, the concurrent marking thread might
2369 // be in the process of clearing the next marking bitmap (which
2370 // we will use for the next cycle if we start one). Starting a
2371 // cycle now will be bad given that parts of the marking
2372 // information might get cleared by the marking thread. And we
2373 // cannot wait for the marking thread to finish the cycle as it
2374 // periodically yields while clearing the next marking bitmap
2375 // and, if it's in a yield point, it's waiting for us to
2376 // finish. So, at this point we will not start a cycle and we'll
2377 // let the concurrent marking thread complete the last one.
2378 }
2379 }
2380 }
2382 void
2383 G1CollectorPolicy_BestRegionsFirst::
2384 record_collection_pause_start(double start_time_sec, size_t start_used) {
2385 G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
2386 }
2388 class NextNonCSElemFinder: public HeapRegionClosure {
2389 HeapRegion* _res;
2390 public:
2391 NextNonCSElemFinder(): _res(NULL) {}
2392 bool doHeapRegion(HeapRegion* r) {
2393 if (!r->in_collection_set()) {
2394 _res = r;
2395 return true;
2396 } else {
2397 return false;
2398 }
2399 }
2400 HeapRegion* res() { return _res; }
2401 };
2403 class KnownGarbageClosure: public HeapRegionClosure {
2404 CollectionSetChooser* _hrSorted;
2406 public:
2407 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
2408 _hrSorted(hrSorted)
2409 {}
2411 bool doHeapRegion(HeapRegion* r) {
2412 // We only include humongous regions in collection
2413 // sets when concurrent mark shows that their contained object is
2414 // unreachable.
2416 // Do we have any marking information for this region?
2417 if (r->is_marked()) {
2418 // We don't include humongous regions in collection
2419 // sets because we collect them immediately at the end of a marking
2420 // cycle. We also don't include young regions because we *must*
2421 // include them in the next collection pause.
2422 if (!r->isHumongous() && !r->is_young()) {
2423 _hrSorted->addMarkedHeapRegion(r);
2424 }
2425 }
2426 return false;
2427 }
2428 };
2430 class ParKnownGarbageHRClosure: public HeapRegionClosure {
2431 CollectionSetChooser* _hrSorted;
2432 jint _marked_regions_added;
2433 jint _chunk_size;
2434 jint _cur_chunk_idx;
2435 jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
2436 int _worker;
2437 int _invokes;
2439 void get_new_chunk() {
2440 _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
2441 _cur_chunk_end = _cur_chunk_idx + _chunk_size;
2442 }
2443 void add_region(HeapRegion* r) {
2444 if (_cur_chunk_idx == _cur_chunk_end) {
2445 get_new_chunk();
2446 }
2447 assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
2448 _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
2449 _marked_regions_added++;
2450 _cur_chunk_idx++;
2451 }
2453 public:
2454 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
2455 jint chunk_size,
2456 int worker) :
2457 _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
2458 _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
2459 _invokes(0)
2460 {}
2462 bool doHeapRegion(HeapRegion* r) {
2463 // We only include humongous regions in collection
2464 // sets when concurrent mark shows that their contained object is
2465 // unreachable.
2466 _invokes++;
2468 // Do we have any marking information for this region?
2469 if (r->is_marked()) {
2470 // We don't include humongous regions in collection
2471 // sets because we collect them immediately at the end of a marking
2472 // cycle.
2473 // We also do not include young regions in collection sets
2474 if (!r->isHumongous() && !r->is_young()) {
2475 add_region(r);
2476 }
2477 }
2478 return false;
2479 }
2480 jint marked_regions_added() { return _marked_regions_added; }
2481 int invokes() { return _invokes; }
2482 };
2484 class ParKnownGarbageTask: public AbstractGangTask {
2485 CollectionSetChooser* _hrSorted;
2486 jint _chunk_size;
2487 G1CollectedHeap* _g1;
2488 public:
2489 ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
2490 AbstractGangTask("ParKnownGarbageTask"),
2491 _hrSorted(hrSorted), _chunk_size(chunk_size),
2492 _g1(G1CollectedHeap::heap())
2493 {}
2495 void work(int i) {
2496 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
2497 // Back to zero for the claim value.
2498 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
2499 HeapRegion::InitialClaimValue);
2500 jint regions_added = parKnownGarbageCl.marked_regions_added();
2501 _hrSorted->incNumMarkedHeapRegions(regions_added);
2502 if (G1PrintParCleanupStats) {
2503 gclog_or_tty->print(" Thread %d called %d times, added %d regions to list.\n",
2504 i, parKnownGarbageCl.invokes(), regions_added);
2505 }
2506 }
2507 };
2509 void
2510 G1CollectorPolicy_BestRegionsFirst::
2511 record_concurrent_mark_cleanup_end(size_t freed_bytes,
2512 size_t max_live_bytes) {
2513 double start;
2514 if (G1PrintParCleanupStats) start = os::elapsedTime();
2515 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
2517 _collectionSetChooser->clearMarkedHeapRegions();
2518 double clear_marked_end;
2519 if (G1PrintParCleanupStats) {
2520 clear_marked_end = os::elapsedTime();
2521 gclog_or_tty->print_cr(" clear marked regions + work1: %8.3f ms.",
2522 (clear_marked_end - start)*1000.0);
2523 }
2524 if (ParallelGCThreads > 0) {
2525 const size_t OverpartitionFactor = 4;
2526 const size_t MinWorkUnit = 8;
2527 const size_t WorkUnit =
2528 MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
2529 MinWorkUnit);
2530 _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
2531 WorkUnit);
2532 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
2533 (int) WorkUnit);
2534 _g1->workers()->run_task(&parKnownGarbageTask);
2536 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
2537 "sanity check");
2538 } else {
2539 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
2540 _g1->heap_region_iterate(&knownGarbagecl);
2541 }
2542 double known_garbage_end;
2543 if (G1PrintParCleanupStats) {
2544 known_garbage_end = os::elapsedTime();
2545 gclog_or_tty->print_cr(" compute known garbage: %8.3f ms.",
2546 (known_garbage_end - clear_marked_end)*1000.0);
2547 }
2548 _collectionSetChooser->sortMarkedHeapRegions();
2549 double sort_end;
2550 if (G1PrintParCleanupStats) {
2551 sort_end = os::elapsedTime();
2552 gclog_or_tty->print_cr(" sorting: %8.3f ms.",
2553 (sort_end - known_garbage_end)*1000.0);
2554 }
2556 record_concurrent_mark_cleanup_end_work2();
2557 double work2_end;
2558 if (G1PrintParCleanupStats) {
2559 work2_end = os::elapsedTime();
2560 gclog_or_tty->print_cr(" work2: %8.3f ms.",
2561 (work2_end - sort_end)*1000.0);
2562 }
2563 }
2565 // Add the heap region at the head of the non-incremental collection set
2566 void G1CollectorPolicy::
2567 add_to_collection_set(HeapRegion* hr) {
2568 assert(_inc_cset_build_state == Active, "Precondition");
2569 assert(!hr->is_young(), "non-incremental add of young region");
2571 if (G1PrintHeapRegions) {
2572 gclog_or_tty->print_cr("added region to cset "
2573 "%d:["PTR_FORMAT", "PTR_FORMAT"], "
2574 "top "PTR_FORMAT", %s",
2575 hr->hrs_index(), hr->bottom(), hr->end(),
2576 hr->top(), hr->is_young() ? "YOUNG" : "NOT_YOUNG");
2577 }
2579 if (_g1->mark_in_progress())
2580 _g1->concurrent_mark()->registerCSetRegion(hr);
2582 assert(!hr->in_collection_set(), "should not already be in the CSet");
2583 hr->set_in_collection_set(true);
2584 hr->set_next_in_collection_set(_collection_set);
2585 _collection_set = hr;
2586 _collection_set_size++;
2587 _collection_set_bytes_used_before += hr->used();
2588 _g1->register_region_with_in_cset_fast_test(hr);
2589 }
2591 // Initialize the per-collection-set information
2592 void G1CollectorPolicy::start_incremental_cset_building() {
2593 assert(_inc_cset_build_state == Inactive, "Precondition");
2595 _inc_cset_head = NULL;
2596 _inc_cset_tail = NULL;
2597 _inc_cset_size = 0;
2598 _inc_cset_bytes_used_before = 0;
2600 if (in_young_gc_mode()) {
2601 _inc_cset_young_index = 0;
2602 }
2604 _inc_cset_max_finger = 0;
2605 _inc_cset_recorded_young_bytes = 0;
2606 _inc_cset_recorded_rs_lengths = 0;
2607 _inc_cset_predicted_elapsed_time_ms = 0;
2608 _inc_cset_predicted_bytes_to_copy = 0;
2609 _inc_cset_build_state = Active;
2610 }
2612 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
2613 // This routine is used when:
2614 // * adding survivor regions to the incremental cset at the end of an
2615 // evacuation pause,
2616 // * adding the current allocation region to the incremental cset
2617 // when it is retired, and
2618 // * updating existing policy information for a region in the
2619 // incremental cset via young list RSet sampling.
2620 // Therefore this routine may be called at a safepoint by the
2621 // VM thread, or in-between safepoints by mutator threads (when
2622 // retiring the current allocation region) or a concurrent
2623 // refine thread (RSet sampling).
2625 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
2626 size_t used_bytes = hr->used();
2628 _inc_cset_recorded_rs_lengths += rs_length;
2629 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
2631 _inc_cset_bytes_used_before += used_bytes;
2633 // Cache the values we have added to the aggregated informtion
2634 // in the heap region in case we have to remove this region from
2635 // the incremental collection set, or it is updated by the
2636 // rset sampling code
2637 hr->set_recorded_rs_length(rs_length);
2638 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
2640 #if PREDICTIONS_VERBOSE
2641 size_t bytes_to_copy = predict_bytes_to_copy(hr);
2642 _inc_cset_predicted_bytes_to_copy += bytes_to_copy;
2644 // Record the number of bytes used in this region
2645 _inc_cset_recorded_young_bytes += used_bytes;
2647 // Cache the values we have added to the aggregated informtion
2648 // in the heap region in case we have to remove this region from
2649 // the incremental collection set, or it is updated by the
2650 // rset sampling code
2651 hr->set_predicted_bytes_to_copy(bytes_to_copy);
2652 #endif // PREDICTIONS_VERBOSE
2653 }
2655 void G1CollectorPolicy::remove_from_incremental_cset_info(HeapRegion* hr) {
2656 // This routine is currently only called as part of the updating of
2657 // existing policy information for regions in the incremental cset that
2658 // is performed by the concurrent refine thread(s) as part of young list
2659 // RSet sampling. Therefore we should not be at a safepoint.
2661 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
2662 assert(hr->is_young(), "it should be");
2664 size_t used_bytes = hr->used();
2665 size_t old_rs_length = hr->recorded_rs_length();
2666 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
2668 // Subtract the old recorded/predicted policy information for
2669 // the given heap region from the collection set info.
2670 _inc_cset_recorded_rs_lengths -= old_rs_length;
2671 _inc_cset_predicted_elapsed_time_ms -= old_elapsed_time_ms;
2673 _inc_cset_bytes_used_before -= used_bytes;
2675 // Clear the values cached in the heap region
2676 hr->set_recorded_rs_length(0);
2677 hr->set_predicted_elapsed_time_ms(0);
2679 #if PREDICTIONS_VERBOSE
2680 size_t old_predicted_bytes_to_copy = hr->predicted_bytes_to_copy();
2681 _inc_cset_predicted_bytes_to_copy -= old_predicted_bytes_to_copy;
2683 // Subtract the number of bytes used in this region
2684 _inc_cset_recorded_young_bytes -= used_bytes;
2686 // Clear the values cached in the heap region
2687 hr->set_predicted_bytes_to_copy(0);
2688 #endif // PREDICTIONS_VERBOSE
2689 }
2691 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length) {
2692 // Update the collection set information that is dependent on the new RS length
2693 assert(hr->is_young(), "Precondition");
2695 remove_from_incremental_cset_info(hr);
2696 add_to_incremental_cset_info(hr, new_rs_length);
2697 }
2699 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
2700 assert( hr->is_young(), "invariant");
2701 assert( hr->young_index_in_cset() == -1, "invariant" );
2702 assert(_inc_cset_build_state == Active, "Precondition");
2704 // We need to clear and set the cached recorded/cached collection set
2705 // information in the heap region here (before the region gets added
2706 // to the collection set). An individual heap region's cached values
2707 // are calculated, aggregated with the policy collection set info,
2708 // and cached in the heap region here (initially) and (subsequently)
2709 // by the Young List sampling code.
2711 size_t rs_length = hr->rem_set()->occupied();
2712 add_to_incremental_cset_info(hr, rs_length);
2714 HeapWord* hr_end = hr->end();
2715 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
2717 assert(!hr->in_collection_set(), "invariant");
2718 hr->set_in_collection_set(true);
2719 assert( hr->next_in_collection_set() == NULL, "invariant");
2721 _inc_cset_size++;
2722 _g1->register_region_with_in_cset_fast_test(hr);
2724 hr->set_young_index_in_cset((int) _inc_cset_young_index);
2725 ++_inc_cset_young_index;
2726 }
2728 // Add the region at the RHS of the incremental cset
2729 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
2730 // We should only ever be appending survivors at the end of a pause
2731 assert( hr->is_survivor(), "Logic");
2733 // Do the 'common' stuff
2734 add_region_to_incremental_cset_common(hr);
2736 // Now add the region at the right hand side
2737 if (_inc_cset_tail == NULL) {
2738 assert(_inc_cset_head == NULL, "invariant");
2739 _inc_cset_head = hr;
2740 } else {
2741 _inc_cset_tail->set_next_in_collection_set(hr);
2742 }
2743 _inc_cset_tail = hr;
2745 if (G1PrintHeapRegions) {
2746 gclog_or_tty->print_cr(" added region to incremental cset (RHS) "
2747 "%d:["PTR_FORMAT", "PTR_FORMAT"], "
2748 "top "PTR_FORMAT", young %s",
2749 hr->hrs_index(), hr->bottom(), hr->end(),
2750 hr->top(), (hr->is_young()) ? "YES" : "NO");
2751 }
2752 }
2754 // Add the region to the LHS of the incremental cset
2755 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
2756 // Survivors should be added to the RHS at the end of a pause
2757 assert(!hr->is_survivor(), "Logic");
2759 // Do the 'common' stuff
2760 add_region_to_incremental_cset_common(hr);
2762 // Add the region at the left hand side
2763 hr->set_next_in_collection_set(_inc_cset_head);
2764 if (_inc_cset_head == NULL) {
2765 assert(_inc_cset_tail == NULL, "Invariant");
2766 _inc_cset_tail = hr;
2767 }
2768 _inc_cset_head = hr;
2770 if (G1PrintHeapRegions) {
2771 gclog_or_tty->print_cr(" added region to incremental cset (LHS) "
2772 "%d:["PTR_FORMAT", "PTR_FORMAT"], "
2773 "top "PTR_FORMAT", young %s",
2774 hr->hrs_index(), hr->bottom(), hr->end(),
2775 hr->top(), (hr->is_young()) ? "YES" : "NO");
2776 }
2777 }
2779 #ifndef PRODUCT
2780 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
2781 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
2783 st->print_cr("\nCollection_set:");
2784 HeapRegion* csr = list_head;
2785 while (csr != NULL) {
2786 HeapRegion* next = csr->next_in_collection_set();
2787 assert(csr->in_collection_set(), "bad CS");
2788 st->print_cr(" [%08x-%08x], t: %08x, P: %08x, N: %08x, C: %08x, "
2789 "age: %4d, y: %d, surv: %d",
2790 csr->bottom(), csr->end(),
2791 csr->top(),
2792 csr->prev_top_at_mark_start(),
2793 csr->next_top_at_mark_start(),
2794 csr->top_at_conc_mark_count(),
2795 csr->age_in_surv_rate_group_cond(),
2796 csr->is_young(),
2797 csr->is_survivor());
2798 csr = next;
2799 }
2800 }
2801 #endif // !PRODUCT
2803 bool
2804 G1CollectorPolicy_BestRegionsFirst::choose_collection_set() {
2805 // Set this here - in case we're not doing young collections.
2806 double non_young_start_time_sec = os::elapsedTime();
2808 // The result that this routine will return. This will be set to
2809 // false if:
2810 // * we're doing a young or partially young collection and we
2811 // have added the youg regions to collection set, or
2812 // * we add old regions to the collection set.
2813 bool abandon_collection = true;
2815 start_recording_regions();
2817 guarantee(_target_pause_time_ms > -1.0
2818 NOT_PRODUCT(|| Universe::heap()->gc_cause() == GCCause::_scavenge_alot),
2819 "_target_pause_time_ms should have been set!");
2820 #ifndef PRODUCT
2821 if (_target_pause_time_ms <= -1.0) {
2822 assert(ScavengeALot && Universe::heap()->gc_cause() == GCCause::_scavenge_alot, "Error");
2823 _target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
2824 }
2825 #endif
2826 assert(_collection_set == NULL, "Precondition");
2828 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2829 double predicted_pause_time_ms = base_time_ms;
2831 double target_time_ms = _target_pause_time_ms;
2832 double time_remaining_ms = target_time_ms - base_time_ms;
2834 // the 10% and 50% values are arbitrary...
2835 if (time_remaining_ms < 0.10*target_time_ms) {
2836 time_remaining_ms = 0.50 * target_time_ms;
2837 _within_target = false;
2838 } else {
2839 _within_target = true;
2840 }
2842 // We figure out the number of bytes available for future to-space.
2843 // For new regions without marking information, we must assume the
2844 // worst-case of complete survival. If we have marking information for a
2845 // region, we can bound the amount of live data. We can add a number of
2846 // such regions, as long as the sum of the live data bounds does not
2847 // exceed the available evacuation space.
2848 size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes;
2850 size_t expansion_bytes =
2851 _g1->expansion_regions() * HeapRegion::GrainBytes;
2853 _collection_set_bytes_used_before = 0;
2854 _collection_set_size = 0;
2856 // Adjust for expansion and slop.
2857 max_live_bytes = max_live_bytes + expansion_bytes;
2859 assert(_g1->regions_accounted_for(), "Region leakage!");
2861 HeapRegion* hr;
2862 if (in_young_gc_mode()) {
2863 double young_start_time_sec = os::elapsedTime();
2865 if (G1PolicyVerbose > 0) {
2866 gclog_or_tty->print_cr("Adding %d young regions to the CSet",
2867 _g1->young_list()->length());
2868 }
2870 _young_cset_length = 0;
2871 _last_young_gc_full = full_young_gcs() ? true : false;
2873 if (_last_young_gc_full)
2874 ++_full_young_pause_num;
2875 else
2876 ++_partial_young_pause_num;
2878 // The young list is laid with the survivor regions from the previous
2879 // pause are appended to the RHS of the young list, i.e.
2880 // [Newly Young Regions ++ Survivors from last pause].
2882 hr = _g1->young_list()->first_survivor_region();
2883 while (hr != NULL) {
2884 assert(hr->is_survivor(), "badly formed young list");
2885 hr->set_young();
2886 hr = hr->get_next_young_region();
2887 }
2889 // Clear the fields that point to the survivor list - they are
2890 // all young now.
2891 _g1->young_list()->clear_survivors();
2893 if (_g1->mark_in_progress())
2894 _g1->concurrent_mark()->register_collection_set_finger(_inc_cset_max_finger);
2896 _young_cset_length = _inc_cset_young_index;
2897 _collection_set = _inc_cset_head;
2898 _collection_set_size = _inc_cset_size;
2899 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2901 // For young regions in the collection set, we assume the worst
2902 // case of complete survival
2903 max_live_bytes -= _inc_cset_size * HeapRegion::GrainBytes;
2905 time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms;
2906 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
2908 // The number of recorded young regions is the incremental
2909 // collection set's current size
2910 set_recorded_young_regions(_inc_cset_size);
2911 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
2912 set_recorded_young_bytes(_inc_cset_recorded_young_bytes);
2913 #if PREDICTIONS_VERBOSE
2914 set_predicted_bytes_to_copy(_inc_cset_predicted_bytes_to_copy);
2915 #endif // PREDICTIONS_VERBOSE
2917 if (G1PolicyVerbose > 0) {
2918 gclog_or_tty->print_cr(" Added " PTR_FORMAT " Young Regions to CS.",
2919 _inc_cset_size);
2920 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2921 max_live_bytes/K);
2922 }
2924 assert(_inc_cset_size == _g1->young_list()->length(), "Invariant");
2925 if (_inc_cset_size > 0) {
2926 assert(_collection_set != NULL, "Invariant");
2927 abandon_collection = false;
2928 }
2930 double young_end_time_sec = os::elapsedTime();
2931 _recorded_young_cset_choice_time_ms =
2932 (young_end_time_sec - young_start_time_sec) * 1000.0;
2934 // We are doing young collections so reset this.
2935 non_young_start_time_sec = young_end_time_sec;
2937 // Note we can use either _collection_set_size or
2938 // _young_cset_length here
2939 if (_collection_set_size > 0 && _last_young_gc_full) {
2940 // don't bother adding more regions...
2941 goto choose_collection_set_end;
2942 }
2943 }
2945 if (!in_young_gc_mode() || !full_young_gcs()) {
2946 bool should_continue = true;
2947 NumberSeq seq;
2948 double avg_prediction = 100000000000000000.0; // something very large
2950 // Save the current size of the collection set to detect
2951 // if we actually added any old regions.
2952 size_t n_young_regions = _collection_set_size;
2954 do {
2955 hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
2956 avg_prediction);
2957 if (hr != NULL) {
2958 double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
2959 time_remaining_ms -= predicted_time_ms;
2960 predicted_pause_time_ms += predicted_time_ms;
2961 add_to_collection_set(hr);
2962 record_non_young_cset_region(hr);
2963 max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
2964 if (G1PolicyVerbose > 0) {
2965 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2966 max_live_bytes/K);
2967 }
2968 seq.add(predicted_time_ms);
2969 avg_prediction = seq.avg() + seq.sd();
2970 }
2971 should_continue =
2972 ( hr != NULL) &&
2973 ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0
2974 : _collection_set_size < _young_list_fixed_length );
2975 } while (should_continue);
2977 if (!adaptive_young_list_length() &&
2978 _collection_set_size < _young_list_fixed_length)
2979 _should_revert_to_full_young_gcs = true;
2981 if (_collection_set_size > n_young_regions) {
2982 // We actually added old regions to the collection set
2983 // so we are not abandoning this collection.
2984 abandon_collection = false;
2985 }
2986 }
2988 choose_collection_set_end:
2989 stop_incremental_cset_building();
2991 count_CS_bytes_used();
2993 end_recording_regions();
2995 double non_young_end_time_sec = os::elapsedTime();
2996 _recorded_non_young_cset_choice_time_ms =
2997 (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
2999 return abandon_collection;
3000 }
3002 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
3003 G1CollectorPolicy::record_full_collection_end();
3004 _collectionSetChooser->updateAfterFullCollection();
3005 }
3007 void G1CollectorPolicy_BestRegionsFirst::
3008 expand_if_possible(size_t numRegions) {
3009 size_t expansion_bytes = numRegions * HeapRegion::GrainBytes;
3010 _g1->expand(expansion_bytes);
3011 }
3013 void G1CollectorPolicy_BestRegionsFirst::
3014 record_collection_pause_end(bool abandoned) {
3015 G1CollectorPolicy::record_collection_pause_end(abandoned);
3016 assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
3017 }