Wed, 30 Sep 2009 14:50:51 -0400
6890137: G1: revamp reachable object dump
Summary: Revamp the reachable object dump debugging facility.
Reviewed-by: jmasa, apetrusenko
1 /*
2 * Copyright 2001-2009 Sun Microsystems, Inc. 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.
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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).
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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.
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
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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 static double cost_per_scan_only_region_ms_defaults[] = {
46 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
47 };
49 // all the same
50 static double fully_young_cards_per_entry_ratio_defaults[] = {
51 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
52 };
54 static double cost_per_entry_ms_defaults[] = {
55 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
56 };
58 static double cost_per_byte_ms_defaults[] = {
59 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
60 };
62 // these should be pretty consistent
63 static double constant_other_time_ms_defaults[] = {
64 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
65 };
68 static double young_other_cost_per_region_ms_defaults[] = {
69 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
70 };
72 static double non_young_other_cost_per_region_ms_defaults[] = {
73 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
74 };
76 // </NEW PREDICTION>
78 G1CollectorPolicy::G1CollectorPolicy() :
79 _parallel_gc_threads((ParallelGCThreads > 0) ? ParallelGCThreads : 1),
80 _n_pauses(0),
81 _recent_CH_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
82 _recent_G1_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
83 _recent_evac_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
84 _recent_pause_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
85 _recent_rs_sizes(new TruncatedSeq(NumPrevPausesForHeuristics)),
86 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
87 _all_pause_times_ms(new NumberSeq()),
88 _stop_world_start(0.0),
89 _all_stop_world_times_ms(new NumberSeq()),
90 _all_yield_times_ms(new NumberSeq()),
92 _all_mod_union_times_ms(new NumberSeq()),
94 _summary(new Summary()),
95 _abandoned_summary(new AbandonedSummary()),
97 #ifndef PRODUCT
98 _cur_clear_ct_time_ms(0.0),
99 _min_clear_cc_time_ms(-1.0),
100 _max_clear_cc_time_ms(-1.0),
101 _cur_clear_cc_time_ms(0.0),
102 _cum_clear_cc_time_ms(0.0),
103 _num_cc_clears(0L),
104 #endif
106 _region_num_young(0),
107 _region_num_tenured(0),
108 _prev_region_num_young(0),
109 _prev_region_num_tenured(0),
111 _aux_num(10),
112 _all_aux_times_ms(new NumberSeq[_aux_num]),
113 _cur_aux_start_times_ms(new double[_aux_num]),
114 _cur_aux_times_ms(new double[_aux_num]),
115 _cur_aux_times_set(new bool[_aux_num]),
117 _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
118 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
119 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
121 // <NEW PREDICTION>
123 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
124 _prev_collection_pause_end_ms(0.0),
125 _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
126 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
127 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
128 _cost_per_scan_only_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
129 _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
130 _partially_young_cards_per_entry_ratio_seq(
131 new TruncatedSeq(TruncatedSeqLength)),
132 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
133 _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
134 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
135 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
136 _cost_per_scan_only_region_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
137 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
138 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
139 _non_young_other_cost_per_region_ms_seq(
140 new TruncatedSeq(TruncatedSeqLength)),
142 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
143 _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
144 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
146 _pause_time_target_ms((double) MaxGCPauseMillis),
148 // </NEW PREDICTION>
150 _in_young_gc_mode(false),
151 _full_young_gcs(true),
152 _full_young_pause_num(0),
153 _partial_young_pause_num(0),
155 _during_marking(false),
156 _in_marking_window(false),
157 _in_marking_window_im(false),
159 _known_garbage_ratio(0.0),
160 _known_garbage_bytes(0),
162 _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
163 _target_pause_time_ms(-1.0),
165 _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
167 _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
168 _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
170 _recent_avg_pause_time_ratio(0.0),
171 _num_markings(0),
172 _n_marks(0),
173 _n_pauses_at_mark_end(0),
175 _all_full_gc_times_ms(new NumberSeq()),
177 // G1PausesBtwnConcMark defaults to -1
178 // so the hack is to do the cast QQQ FIXME
179 _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
180 _n_marks_since_last_pause(0),
181 _conc_mark_initiated(false),
182 _should_initiate_conc_mark(false),
183 _should_revert_to_full_young_gcs(false),
184 _last_full_young_gc(false),
186 _prev_collection_pause_used_at_end_bytes(0),
188 _collection_set(NULL),
189 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
190 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
191 #endif // _MSC_VER
193 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
194 G1YoungSurvRateNumRegionsSummary)),
195 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
196 G1YoungSurvRateNumRegionsSummary)),
197 // add here any more surv rate groups
198 _recorded_survivor_regions(0),
199 _recorded_survivor_head(NULL),
200 _recorded_survivor_tail(NULL),
201 _survivors_age_table(true)
203 {
204 // Set up the region size and associated fields. Given that the
205 // policy is created before the heap, we have to set this up here,
206 // so it's done as soon as possible.
207 HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
209 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
210 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
212 _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
213 _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
214 _par_last_scan_only_times_ms = new double[_parallel_gc_threads];
215 _par_last_scan_only_regions_scanned = new double[_parallel_gc_threads];
217 _par_last_update_rs_start_times_ms = new double[_parallel_gc_threads];
218 _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
219 _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
221 _par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads];
222 _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
223 _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads];
225 _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
227 _par_last_termination_times_ms = new double[_parallel_gc_threads];
229 // start conservatively
230 _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
232 // <NEW PREDICTION>
234 int index;
235 if (ParallelGCThreads == 0)
236 index = 0;
237 else if (ParallelGCThreads > 8)
238 index = 7;
239 else
240 index = ParallelGCThreads - 1;
242 _pending_card_diff_seq->add(0.0);
243 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
244 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
245 _cost_per_scan_only_region_ms_seq->add(
246 cost_per_scan_only_region_ms_defaults[index]);
247 _fully_young_cards_per_entry_ratio_seq->add(
248 fully_young_cards_per_entry_ratio_defaults[index]);
249 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
250 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
251 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
252 _young_other_cost_per_region_ms_seq->add(
253 young_other_cost_per_region_ms_defaults[index]);
254 _non_young_other_cost_per_region_ms_seq->add(
255 non_young_other_cost_per_region_ms_defaults[index]);
257 // </NEW PREDICTION>
259 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
260 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
261 guarantee(max_gc_time < time_slice,
262 "Max GC time should not be greater than the time slice");
263 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
264 _sigma = (double) G1ConfidencePercent / 100.0;
266 // start conservatively (around 50ms is about right)
267 _concurrent_mark_init_times_ms->add(0.05);
268 _concurrent_mark_remark_times_ms->add(0.05);
269 _concurrent_mark_cleanup_times_ms->add(0.20);
270 _tenuring_threshold = MaxTenuringThreshold;
272 if (G1UseSurvivorSpaces) {
273 // if G1FixedSurvivorSpaceSize is 0 which means the size is not
274 // fixed, then _max_survivor_regions will be calculated at
275 // calculate_young_list_target_config during initialization
276 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
277 } else {
278 _max_survivor_regions = 0;
279 }
281 initialize_all();
282 }
284 // Increment "i", mod "len"
285 static void inc_mod(int& i, int len) {
286 i++; if (i == len) i = 0;
287 }
289 void G1CollectorPolicy::initialize_flags() {
290 set_min_alignment(HeapRegion::GrainBytes);
291 set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
292 if (SurvivorRatio < 1) {
293 vm_exit_during_initialization("Invalid survivor ratio specified");
294 }
295 CollectorPolicy::initialize_flags();
296 }
298 void G1CollectorPolicy::init() {
299 // Set aside an initial future to_space.
300 _g1 = G1CollectedHeap::heap();
301 size_t regions = Universe::heap()->capacity() / HeapRegion::GrainBytes;
303 assert(Heap_lock->owned_by_self(), "Locking discipline.");
305 if (G1SteadyStateUsed < 50) {
306 vm_exit_during_initialization("G1SteadyStateUsed must be at least 50%.");
307 }
309 initialize_gc_policy_counters();
311 if (G1Gen) {
312 _in_young_gc_mode = true;
314 if (G1YoungGenSize == 0) {
315 set_adaptive_young_list_length(true);
316 _young_list_fixed_length = 0;
317 } else {
318 set_adaptive_young_list_length(false);
319 _young_list_fixed_length = (G1YoungGenSize / HeapRegion::GrainBytes);
320 }
321 _free_regions_at_end_of_collection = _g1->free_regions();
322 _scan_only_regions_at_end_of_collection = 0;
323 calculate_young_list_min_length();
324 guarantee( _young_list_min_length == 0, "invariant, not enough info" );
325 calculate_young_list_target_config();
326 } else {
327 _young_list_fixed_length = 0;
328 _in_young_gc_mode = false;
329 }
330 }
332 // Create the jstat counters for the policy.
333 void G1CollectorPolicy::initialize_gc_policy_counters()
334 {
335 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen);
336 }
338 void G1CollectorPolicy::calculate_young_list_min_length() {
339 _young_list_min_length = 0;
341 if (!adaptive_young_list_length())
342 return;
344 if (_alloc_rate_ms_seq->num() > 3) {
345 double now_sec = os::elapsedTime();
346 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
347 double alloc_rate_ms = predict_alloc_rate_ms();
348 int min_regions = (int) ceil(alloc_rate_ms * when_ms);
349 int current_region_num = (int) _g1->young_list_length();
350 _young_list_min_length = min_regions + current_region_num;
351 }
352 }
354 void G1CollectorPolicy::calculate_young_list_target_config() {
355 if (adaptive_young_list_length()) {
356 size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
357 calculate_young_list_target_config(rs_lengths);
358 } else {
359 if (full_young_gcs())
360 _young_list_target_length = _young_list_fixed_length;
361 else
362 _young_list_target_length = _young_list_fixed_length / 2;
363 _young_list_target_length = MAX2(_young_list_target_length, (size_t)1);
364 size_t so_length = calculate_optimal_so_length(_young_list_target_length);
365 guarantee( so_length < _young_list_target_length, "invariant" );
366 _young_list_so_prefix_length = so_length;
367 }
368 calculate_survivors_policy();
369 }
371 // This method calculate the optimal scan-only set for a fixed young
372 // gen size. I couldn't work out how to reuse the more elaborate one,
373 // i.e. calculate_young_list_target_config(rs_length), as the loops are
374 // fundamentally different (the other one finds a config for different
375 // S-O lengths, whereas here we need to do the opposite).
376 size_t G1CollectorPolicy::calculate_optimal_so_length(
377 size_t young_list_length) {
378 if (!G1UseScanOnlyPrefix)
379 return 0;
381 if (_all_pause_times_ms->num() < 3) {
382 // we won't use a scan-only set at the beginning to allow the rest
383 // of the predictors to warm up
384 return 0;
385 }
387 if (_cost_per_scan_only_region_ms_seq->num() < 3) {
388 // then, we'll only set the S-O set to 1 for a little bit of time,
389 // to get enough information on the scanning cost
390 return 1;
391 }
393 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
394 size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
395 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
396 size_t scanned_cards;
397 if (full_young_gcs())
398 scanned_cards = predict_young_card_num(adj_rs_lengths);
399 else
400 scanned_cards = predict_non_young_card_num(adj_rs_lengths);
401 double base_time_ms = predict_base_elapsed_time_ms(pending_cards,
402 scanned_cards);
404 size_t so_length = 0;
405 double max_gc_eff = 0.0;
406 for (size_t i = 0; i < young_list_length; ++i) {
407 double gc_eff = 0.0;
408 double pause_time_ms = 0.0;
409 predict_gc_eff(young_list_length, i, base_time_ms,
410 &gc_eff, &pause_time_ms);
411 if (gc_eff > max_gc_eff) {
412 max_gc_eff = gc_eff;
413 so_length = i;
414 }
415 }
417 // set it to 95% of the optimal to make sure we sample the "area"
418 // around the optimal length to get up-to-date survival rate data
419 return so_length * 950 / 1000;
420 }
422 // This is a really cool piece of code! It finds the best
423 // target configuration (young length / scan-only prefix length) so
424 // that GC efficiency is maximized and that we also meet a pause
425 // time. It's a triple nested loop. These loops are explained below
426 // from the inside-out :-)
427 //
428 // (a) The innermost loop will try to find the optimal young length
429 // for a fixed S-O length. It uses a binary search to speed up the
430 // process. We assume that, for a fixed S-O length, as we add more
431 // young regions to the CSet, the GC efficiency will only go up (I'll
432 // skip the proof). So, using a binary search to optimize this process
433 // makes perfect sense.
434 //
435 // (b) The middle loop will fix the S-O length before calling the
436 // innermost one. It will vary it between two parameters, increasing
437 // it by a given increment.
438 //
439 // (c) The outermost loop will call the middle loop three times.
440 // (1) The first time it will explore all possible S-O length values
441 // from 0 to as large as it can get, using a coarse increment (to
442 // quickly "home in" to where the optimal seems to be).
443 // (2) The second time it will explore the values around the optimal
444 // that was found by the first iteration using a fine increment.
445 // (3) Once the optimal config has been determined by the second
446 // iteration, we'll redo the calculation, but setting the S-O length
447 // to 95% of the optimal to make sure we sample the "area"
448 // around the optimal length to get up-to-date survival rate data
449 //
450 // Termination conditions for the iterations are several: the pause
451 // time is over the limit, we do not have enough to-space, etc.
453 void G1CollectorPolicy::calculate_young_list_target_config(size_t rs_lengths) {
454 guarantee( adaptive_young_list_length(), "pre-condition" );
456 double start_time_sec = os::elapsedTime();
457 size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1MinReservePercent);
458 min_reserve_perc = MIN2((size_t) 50, min_reserve_perc);
459 size_t reserve_regions =
460 (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0);
462 if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
463 // we are in fully-young mode and there are free regions in the heap
465 double survivor_regions_evac_time =
466 predict_survivor_regions_evac_time();
468 size_t min_so_length = 0;
469 size_t max_so_length = 0;
471 if (G1UseScanOnlyPrefix) {
472 if (_all_pause_times_ms->num() < 3) {
473 // we won't use a scan-only set at the beginning to allow the rest
474 // of the predictors to warm up
475 min_so_length = 0;
476 max_so_length = 0;
477 } else if (_cost_per_scan_only_region_ms_seq->num() < 3) {
478 // then, we'll only set the S-O set to 1 for a little bit of time,
479 // to get enough information on the scanning cost
480 min_so_length = 1;
481 max_so_length = 1;
482 } else if (_in_marking_window || _last_full_young_gc) {
483 // no S-O prefix during a marking phase either, as at the end
484 // of the marking phase we'll have to use a very small young
485 // length target to fill up the rest of the CSet with
486 // non-young regions and, if we have lots of scan-only regions
487 // left-over, we will not be able to add any more non-young
488 // regions.
489 min_so_length = 0;
490 max_so_length = 0;
491 } else {
492 // this is the common case; we'll never reach the maximum, we
493 // one of the end conditions will fire well before that
494 // (hopefully!)
495 min_so_length = 0;
496 max_so_length = _free_regions_at_end_of_collection - 1;
497 }
498 } else {
499 // no S-O prefix, as the switch is not set, but we still need to
500 // do one iteration to calculate the best young target that
501 // meets the pause time; this way we reuse the same code instead
502 // of replicating it
503 min_so_length = 0;
504 max_so_length = 0;
505 }
507 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
508 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
509 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
510 size_t scanned_cards;
511 if (full_young_gcs())
512 scanned_cards = predict_young_card_num(adj_rs_lengths);
513 else
514 scanned_cards = predict_non_young_card_num(adj_rs_lengths);
515 // calculate this once, so that we don't have to recalculate it in
516 // the innermost loop
517 double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards)
518 + survivor_regions_evac_time;
519 // the result
520 size_t final_young_length = 0;
521 size_t final_so_length = 0;
522 double final_gc_eff = 0.0;
523 // we'll also keep track of how many times we go into the inner loop
524 // this is for profiling reasons
525 size_t calculations = 0;
527 // this determines which of the three iterations the outer loop is in
528 typedef enum {
529 pass_type_coarse,
530 pass_type_fine,
531 pass_type_final
532 } pass_type_t;
534 // range of the outer loop's iteration
535 size_t from_so_length = min_so_length;
536 size_t to_so_length = max_so_length;
537 guarantee( from_so_length <= to_so_length, "invariant" );
539 // this will keep the S-O length that's found by the second
540 // iteration of the outer loop; we'll keep it just in case the third
541 // iteration fails to find something
542 size_t fine_so_length = 0;
544 // the increment step for the coarse (first) iteration
545 size_t so_coarse_increments = 5;
547 // the common case, we'll start with the coarse iteration
548 pass_type_t pass = pass_type_coarse;
549 size_t so_length_incr = so_coarse_increments;
551 if (from_so_length == to_so_length) {
552 // not point in doing the coarse iteration, we'll go directly into
553 // the fine one (we essentially trying to find the optimal young
554 // length for a fixed S-O length).
555 so_length_incr = 1;
556 pass = pass_type_final;
557 } else if (to_so_length - from_so_length < 3 * so_coarse_increments) {
558 // again, the range is too short so no point in foind the coarse
559 // iteration either
560 so_length_incr = 1;
561 pass = pass_type_fine;
562 }
564 bool done = false;
565 // this is the outermost loop
566 while (!done) {
567 #ifdef TRACE_CALC_YOUNG_CONFIG
568 // leave this in for debugging, just in case
569 gclog_or_tty->print_cr("searching between " SIZE_FORMAT " and " SIZE_FORMAT
570 ", incr " SIZE_FORMAT ", pass %s",
571 from_so_length, to_so_length, so_length_incr,
572 (pass == pass_type_coarse) ? "coarse" :
573 (pass == pass_type_fine) ? "fine" : "final");
574 #endif // TRACE_CALC_YOUNG_CONFIG
576 size_t so_length = from_so_length;
577 size_t init_free_regions =
578 MAX2((size_t)0,
579 _free_regions_at_end_of_collection +
580 _scan_only_regions_at_end_of_collection - reserve_regions);
582 // this determines whether a configuration was found
583 bool gc_eff_set = false;
584 // this is the middle loop
585 while (so_length <= to_so_length) {
586 // base time, which excludes region-related time; again we
587 // calculate it once to avoid recalculating it in the
588 // innermost loop
589 double base_time_with_so_ms =
590 base_time_ms + predict_scan_only_time_ms(so_length);
591 // it's already over the pause target, go around
592 if (base_time_with_so_ms > target_pause_time_ms)
593 break;
595 size_t starting_young_length = so_length+1;
597 // we make sure that the short young length that makes sense
598 // (one more than the S-O length) is feasible
599 size_t min_young_length = starting_young_length;
600 double min_gc_eff;
601 bool min_ok;
602 ++calculations;
603 min_ok = predict_gc_eff(min_young_length, so_length,
604 base_time_with_so_ms,
605 init_free_regions, target_pause_time_ms,
606 &min_gc_eff);
608 if (min_ok) {
609 // the shortest young length is indeed feasible; we'll know
610 // set up the max young length and we'll do a binary search
611 // between min_young_length and max_young_length
612 size_t max_young_length = _free_regions_at_end_of_collection - 1;
613 double max_gc_eff = 0.0;
614 bool max_ok = false;
616 // the innermost loop! (finally!)
617 while (max_young_length > min_young_length) {
618 // we'll make sure that min_young_length is always at a
619 // feasible config
620 guarantee( min_ok, "invariant" );
622 ++calculations;
623 max_ok = predict_gc_eff(max_young_length, so_length,
624 base_time_with_so_ms,
625 init_free_regions, target_pause_time_ms,
626 &max_gc_eff);
628 size_t diff = (max_young_length - min_young_length) / 2;
629 if (max_ok) {
630 min_young_length = max_young_length;
631 min_gc_eff = max_gc_eff;
632 min_ok = true;
633 }
634 max_young_length = min_young_length + diff;
635 }
637 // the innermost loop found a config
638 guarantee( min_ok, "invariant" );
639 if (min_gc_eff > final_gc_eff) {
640 // it's the best config so far, so we'll keep it
641 final_gc_eff = min_gc_eff;
642 final_young_length = min_young_length;
643 final_so_length = so_length;
644 gc_eff_set = true;
645 }
646 }
648 // incremental the fixed S-O length and go around
649 so_length += so_length_incr;
650 }
652 // this is the end of the outermost loop and we need to decide
653 // what to do during the next iteration
654 if (pass == pass_type_coarse) {
655 // we just did the coarse pass (first iteration)
657 if (!gc_eff_set)
658 // we didn't find a feasible config so we'll just bail out; of
659 // course, it might be the case that we missed it; but I'd say
660 // it's a bit unlikely
661 done = true;
662 else {
663 // We did find a feasible config with optimal GC eff during
664 // the first pass. So the second pass we'll only consider the
665 // S-O lengths around that config with a fine increment.
667 guarantee( so_length_incr == so_coarse_increments, "invariant" );
668 guarantee( final_so_length >= min_so_length, "invariant" );
670 #ifdef TRACE_CALC_YOUNG_CONFIG
671 // leave this in for debugging, just in case
672 gclog_or_tty->print_cr(" coarse pass: SO length " SIZE_FORMAT,
673 final_so_length);
674 #endif // TRACE_CALC_YOUNG_CONFIG
676 from_so_length =
677 (final_so_length - min_so_length > so_coarse_increments) ?
678 final_so_length - so_coarse_increments + 1 : min_so_length;
679 to_so_length =
680 (max_so_length - final_so_length > so_coarse_increments) ?
681 final_so_length + so_coarse_increments - 1 : max_so_length;
683 pass = pass_type_fine;
684 so_length_incr = 1;
685 }
686 } else if (pass == pass_type_fine) {
687 // we just finished the second pass
689 if (!gc_eff_set) {
690 // we didn't find a feasible config (yes, it's possible;
691 // notice that, sometimes, we go directly into the fine
692 // iteration and skip the coarse one) so we bail out
693 done = true;
694 } else {
695 // We did find a feasible config with optimal GC eff
696 guarantee( so_length_incr == 1, "invariant" );
698 if (final_so_length == 0) {
699 // The config is of an empty S-O set, so we'll just bail out
700 done = true;
701 } else {
702 // we'll go around once more, setting the S-O length to 95%
703 // of the optimal
704 size_t new_so_length = 950 * final_so_length / 1000;
706 #ifdef TRACE_CALC_YOUNG_CONFIG
707 // leave this in for debugging, just in case
708 gclog_or_tty->print_cr(" fine pass: SO length " SIZE_FORMAT
709 ", setting it to " SIZE_FORMAT,
710 final_so_length, new_so_length);
711 #endif // TRACE_CALC_YOUNG_CONFIG
713 from_so_length = new_so_length;
714 to_so_length = new_so_length;
715 fine_so_length = final_so_length;
717 pass = pass_type_final;
718 }
719 }
720 } else if (pass == pass_type_final) {
721 // we just finished the final (third) pass
723 if (!gc_eff_set)
724 // we didn't find a feasible config, so we'll just use the one
725 // we found during the second pass, which we saved
726 final_so_length = fine_so_length;
728 // and we're done!
729 done = true;
730 } else {
731 guarantee( false, "should never reach here" );
732 }
734 // we now go around the outermost loop
735 }
737 // we should have at least one region in the target young length
738 _young_list_target_length =
739 MAX2((size_t) 1, final_young_length + _recorded_survivor_regions);
740 if (final_so_length >= final_young_length)
741 // and we need to ensure that the S-O length is not greater than
742 // the target young length (this is being a bit careful)
743 final_so_length = 0;
744 _young_list_so_prefix_length = final_so_length;
745 guarantee( !_in_marking_window || !_last_full_young_gc ||
746 _young_list_so_prefix_length == 0, "invariant" );
748 // let's keep an eye of how long we spend on this calculation
749 // right now, I assume that we'll print it when we need it; we
750 // should really adde it to the breakdown of a pause
751 double end_time_sec = os::elapsedTime();
752 double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
754 #ifdef TRACE_CALC_YOUNG_CONFIG
755 // leave this in for debugging, just in case
756 gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT
757 ", SO = " SIZE_FORMAT ", "
758 "elapsed %1.2lf ms, calcs: " SIZE_FORMAT " (%s%s) "
759 SIZE_FORMAT SIZE_FORMAT,
760 target_pause_time_ms,
761 _young_list_target_length - _young_list_so_prefix_length,
762 _young_list_so_prefix_length,
763 elapsed_time_ms,
764 calculations,
765 full_young_gcs() ? "full" : "partial",
766 should_initiate_conc_mark() ? " i-m" : "",
767 _in_marking_window,
768 _in_marking_window_im);
769 #endif // TRACE_CALC_YOUNG_CONFIG
771 if (_young_list_target_length < _young_list_min_length) {
772 // bummer; this means that, if we do a pause when the optimal
773 // config dictates, we'll violate the pause spacing target (the
774 // min length was calculate based on the application's current
775 // alloc rate);
777 // so, we have to bite the bullet, and allocate the minimum
778 // number. We'll violate our target, but we just can't meet it.
780 size_t so_length = 0;
781 // a note further up explains why we do not want an S-O length
782 // during marking
783 if (!_in_marking_window && !_last_full_young_gc)
784 // but we can still try to see whether we can find an optimal
785 // S-O length
786 so_length = calculate_optimal_so_length(_young_list_min_length);
788 #ifdef TRACE_CALC_YOUNG_CONFIG
789 // leave this in for debugging, just in case
790 gclog_or_tty->print_cr("adjusted target length from "
791 SIZE_FORMAT " to " SIZE_FORMAT
792 ", SO " SIZE_FORMAT,
793 _young_list_target_length, _young_list_min_length,
794 so_length);
795 #endif // TRACE_CALC_YOUNG_CONFIG
797 _young_list_target_length =
798 MAX2(_young_list_min_length, (size_t)1);
799 _young_list_so_prefix_length = so_length;
800 }
801 } else {
802 // we are in a partially-young mode or we've run out of regions (due
803 // to evacuation failure)
805 #ifdef TRACE_CALC_YOUNG_CONFIG
806 // leave this in for debugging, just in case
807 gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
808 ", SO " SIZE_FORMAT,
809 _young_list_min_length, 0);
810 #endif // TRACE_CALC_YOUNG_CONFIG
812 // we'll do the pause as soon as possible and with no S-O prefix
813 // (see above for the reasons behind the latter)
814 _young_list_target_length =
815 MAX2(_young_list_min_length, (size_t) 1);
816 _young_list_so_prefix_length = 0;
817 }
819 _rs_lengths_prediction = rs_lengths;
820 }
822 // This is used by: calculate_optimal_so_length(length). It returns
823 // the GC eff and predicted pause time for a particular config
824 void
825 G1CollectorPolicy::predict_gc_eff(size_t young_length,
826 size_t so_length,
827 double base_time_ms,
828 double* ret_gc_eff,
829 double* ret_pause_time_ms) {
830 double so_time_ms = predict_scan_only_time_ms(so_length);
831 double accum_surv_rate_adj = 0.0;
832 if (so_length > 0)
833 accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
834 double accum_surv_rate =
835 accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
836 size_t bytes_to_copy =
837 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
838 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
839 double young_other_time_ms =
840 predict_young_other_time_ms(young_length - so_length);
841 double pause_time_ms =
842 base_time_ms + so_time_ms + copy_time_ms + young_other_time_ms;
843 size_t reclaimed_bytes =
844 (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
845 double gc_eff = (double) reclaimed_bytes / pause_time_ms;
847 *ret_gc_eff = gc_eff;
848 *ret_pause_time_ms = pause_time_ms;
849 }
851 // This is used by: calculate_young_list_target_config(rs_length). It
852 // returns the GC eff of a particular config. It returns false if that
853 // config violates any of the end conditions of the search in the
854 // calling method, or true upon success. The end conditions were put
855 // here since it's called twice and it was best not to replicate them
856 // in the caller. Also, passing the parameteres avoids having to
857 // recalculate them in the innermost loop.
858 bool
859 G1CollectorPolicy::predict_gc_eff(size_t young_length,
860 size_t so_length,
861 double base_time_with_so_ms,
862 size_t init_free_regions,
863 double target_pause_time_ms,
864 double* ret_gc_eff) {
865 *ret_gc_eff = 0.0;
867 if (young_length >= init_free_regions)
868 // end condition 1: not enough space for the young regions
869 return false;
871 double accum_surv_rate_adj = 0.0;
872 if (so_length > 0)
873 accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
874 double accum_surv_rate =
875 accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
876 size_t bytes_to_copy =
877 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
878 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
879 double young_other_time_ms =
880 predict_young_other_time_ms(young_length - so_length);
881 double pause_time_ms =
882 base_time_with_so_ms + copy_time_ms + young_other_time_ms;
884 if (pause_time_ms > target_pause_time_ms)
885 // end condition 2: over the target pause time
886 return false;
888 size_t reclaimed_bytes =
889 (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
890 size_t free_bytes =
891 (init_free_regions - young_length) * HeapRegion::GrainBytes;
893 if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes)
894 // end condition 3: out of to-space (conservatively)
895 return false;
897 // success!
898 double gc_eff = (double) reclaimed_bytes / pause_time_ms;
899 *ret_gc_eff = gc_eff;
901 return true;
902 }
904 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
905 double survivor_regions_evac_time = 0.0;
906 for (HeapRegion * r = _recorded_survivor_head;
907 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
908 r = r->get_next_young_region()) {
909 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
910 }
911 return survivor_regions_evac_time;
912 }
914 void G1CollectorPolicy::check_prediction_validity() {
915 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
917 size_t rs_lengths = _g1->young_list_sampled_rs_lengths();
918 if (rs_lengths > _rs_lengths_prediction) {
919 // add 10% to avoid having to recalculate often
920 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
921 calculate_young_list_target_config(rs_lengths_prediction);
922 }
923 }
925 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
926 bool is_tlab,
927 bool* gc_overhead_limit_was_exceeded) {
928 guarantee(false, "Not using this policy feature yet.");
929 return NULL;
930 }
932 // This method controls how a collector handles one or more
933 // of its generations being fully allocated.
934 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
935 bool is_tlab) {
936 guarantee(false, "Not using this policy feature yet.");
937 return NULL;
938 }
941 #ifndef PRODUCT
942 bool G1CollectorPolicy::verify_young_ages() {
943 HeapRegion* head = _g1->young_list_first_region();
944 return
945 verify_young_ages(head, _short_lived_surv_rate_group);
946 // also call verify_young_ages on any additional surv rate groups
947 }
949 bool
950 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
951 SurvRateGroup *surv_rate_group) {
952 guarantee( surv_rate_group != NULL, "pre-condition" );
954 const char* name = surv_rate_group->name();
955 bool ret = true;
956 int prev_age = -1;
958 for (HeapRegion* curr = head;
959 curr != NULL;
960 curr = curr->get_next_young_region()) {
961 SurvRateGroup* group = curr->surv_rate_group();
962 if (group == NULL && !curr->is_survivor()) {
963 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
964 ret = false;
965 }
967 if (surv_rate_group == group) {
968 int age = curr->age_in_surv_rate_group();
970 if (age < 0) {
971 gclog_or_tty->print_cr("## %s: encountered negative age", name);
972 ret = false;
973 }
975 if (age <= prev_age) {
976 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
977 "(%d, %d)", name, age, prev_age);
978 ret = false;
979 }
980 prev_age = age;
981 }
982 }
984 return ret;
985 }
986 #endif // PRODUCT
988 void G1CollectorPolicy::record_full_collection_start() {
989 _cur_collection_start_sec = os::elapsedTime();
990 // Release the future to-space so that it is available for compaction into.
991 _g1->set_full_collection();
992 }
994 void G1CollectorPolicy::record_full_collection_end() {
995 // Consider this like a collection pause for the purposes of allocation
996 // since last pause.
997 double end_sec = os::elapsedTime();
998 double full_gc_time_sec = end_sec - _cur_collection_start_sec;
999 double full_gc_time_ms = full_gc_time_sec * 1000.0;
1001 _all_full_gc_times_ms->add(full_gc_time_ms);
1003 update_recent_gc_times(end_sec, full_gc_time_ms);
1005 _g1->clear_full_collection();
1007 // "Nuke" the heuristics that control the fully/partially young GC
1008 // transitions and make sure we start with fully young GCs after the
1009 // Full GC.
1010 set_full_young_gcs(true);
1011 _last_full_young_gc = false;
1012 _should_revert_to_full_young_gcs = false;
1013 _should_initiate_conc_mark = false;
1014 _known_garbage_bytes = 0;
1015 _known_garbage_ratio = 0.0;
1016 _in_marking_window = false;
1017 _in_marking_window_im = false;
1019 _short_lived_surv_rate_group->record_scan_only_prefix(0);
1020 _short_lived_surv_rate_group->start_adding_regions();
1021 // also call this on any additional surv rate groups
1023 record_survivor_regions(0, NULL, NULL);
1025 _prev_region_num_young = _region_num_young;
1026 _prev_region_num_tenured = _region_num_tenured;
1028 _free_regions_at_end_of_collection = _g1->free_regions();
1029 _scan_only_regions_at_end_of_collection = 0;
1030 // Reset survivors SurvRateGroup.
1031 _survivor_surv_rate_group->reset();
1032 calculate_young_list_min_length();
1033 calculate_young_list_target_config();
1034 }
1036 void G1CollectorPolicy::record_before_bytes(size_t bytes) {
1037 _bytes_in_to_space_before_gc += bytes;
1038 }
1040 void G1CollectorPolicy::record_after_bytes(size_t bytes) {
1041 _bytes_in_to_space_after_gc += bytes;
1042 }
1044 void G1CollectorPolicy::record_stop_world_start() {
1045 _stop_world_start = os::elapsedTime();
1046 }
1048 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
1049 size_t start_used) {
1050 if (PrintGCDetails) {
1051 gclog_or_tty->stamp(PrintGCTimeStamps);
1052 gclog_or_tty->print("[GC pause");
1053 if (in_young_gc_mode())
1054 gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
1055 }
1057 assert(_g1->used_regions() == _g1->recalculate_used_regions(),
1058 "sanity");
1059 assert(_g1->used() == _g1->recalculate_used(), "sanity");
1061 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
1062 _all_stop_world_times_ms->add(s_w_t_ms);
1063 _stop_world_start = 0.0;
1065 _cur_collection_start_sec = start_time_sec;
1066 _cur_collection_pause_used_at_start_bytes = start_used;
1067 _cur_collection_pause_used_regions_at_start = _g1->used_regions();
1068 _pending_cards = _g1->pending_card_num();
1069 _max_pending_cards = _g1->max_pending_card_num();
1071 _bytes_in_to_space_before_gc = 0;
1072 _bytes_in_to_space_after_gc = 0;
1073 _bytes_in_collection_set_before_gc = 0;
1075 #ifdef DEBUG
1076 // initialise these to something well known so that we can spot
1077 // if they are not set properly
1079 for (int i = 0; i < _parallel_gc_threads; ++i) {
1080 _par_last_ext_root_scan_times_ms[i] = -666.0;
1081 _par_last_mark_stack_scan_times_ms[i] = -666.0;
1082 _par_last_scan_only_times_ms[i] = -666.0;
1083 _par_last_scan_only_regions_scanned[i] = -666.0;
1084 _par_last_update_rs_start_times_ms[i] = -666.0;
1085 _par_last_update_rs_times_ms[i] = -666.0;
1086 _par_last_update_rs_processed_buffers[i] = -666.0;
1087 _par_last_scan_rs_start_times_ms[i] = -666.0;
1088 _par_last_scan_rs_times_ms[i] = -666.0;
1089 _par_last_scan_new_refs_times_ms[i] = -666.0;
1090 _par_last_obj_copy_times_ms[i] = -666.0;
1091 _par_last_termination_times_ms[i] = -666.0;
1092 }
1093 #endif
1095 for (int i = 0; i < _aux_num; ++i) {
1096 _cur_aux_times_ms[i] = 0.0;
1097 _cur_aux_times_set[i] = false;
1098 }
1100 _satb_drain_time_set = false;
1101 _last_satb_drain_processed_buffers = -1;
1103 if (in_young_gc_mode())
1104 _last_young_gc_full = false;
1107 // do that for any other surv rate groups
1108 _short_lived_surv_rate_group->stop_adding_regions();
1109 size_t short_lived_so_length = _young_list_so_prefix_length;
1110 _short_lived_surv_rate_group->record_scan_only_prefix(short_lived_so_length);
1111 tag_scan_only(short_lived_so_length);
1113 if (G1UseSurvivorSpaces) {
1114 _survivors_age_table.clear();
1115 }
1117 assert( verify_young_ages(), "region age verification" );
1118 }
1120 void G1CollectorPolicy::tag_scan_only(size_t short_lived_scan_only_length) {
1121 // done in a way that it can be extended for other surv rate groups too...
1123 HeapRegion* head = _g1->young_list_first_region();
1124 bool finished_short_lived = (short_lived_scan_only_length == 0);
1126 if (finished_short_lived)
1127 return;
1129 for (HeapRegion* curr = head;
1130 curr != NULL;
1131 curr = curr->get_next_young_region()) {
1132 SurvRateGroup* surv_rate_group = curr->surv_rate_group();
1133 int age = curr->age_in_surv_rate_group();
1135 if (surv_rate_group == _short_lived_surv_rate_group) {
1136 if ((size_t)age < short_lived_scan_only_length)
1137 curr->set_scan_only();
1138 else
1139 finished_short_lived = true;
1140 }
1143 if (finished_short_lived)
1144 return;
1145 }
1147 guarantee( false, "we should never reach here" );
1148 }
1150 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
1151 _mark_closure_time_ms = mark_closure_time_ms;
1152 }
1154 void G1CollectorPolicy::record_concurrent_mark_init_start() {
1155 _mark_init_start_sec = os::elapsedTime();
1156 guarantee(!in_young_gc_mode(), "should not do be here in young GC mode");
1157 }
1159 void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double
1160 mark_init_elapsed_time_ms) {
1161 _during_marking = true;
1162 _should_initiate_conc_mark = false;
1163 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
1164 }
1166 void G1CollectorPolicy::record_concurrent_mark_init_end() {
1167 double end_time_sec = os::elapsedTime();
1168 double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
1169 _concurrent_mark_init_times_ms->add(elapsed_time_ms);
1170 record_concurrent_mark_init_end_pre(elapsed_time_ms);
1172 _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true);
1173 }
1175 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
1176 _mark_remark_start_sec = os::elapsedTime();
1177 _during_marking = false;
1178 }
1180 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
1181 double end_time_sec = os::elapsedTime();
1182 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
1183 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
1184 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1185 _prev_collection_pause_end_ms += elapsed_time_ms;
1187 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
1188 }
1190 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
1191 _mark_cleanup_start_sec = os::elapsedTime();
1192 }
1194 void
1195 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
1196 size_t max_live_bytes) {
1197 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
1198 record_concurrent_mark_cleanup_end_work2();
1199 }
1201 void
1202 G1CollectorPolicy::
1203 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
1204 size_t max_live_bytes) {
1205 if (_n_marks < 2) _n_marks++;
1206 if (G1PolicyVerbose > 0)
1207 gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB "
1208 " (of " SIZE_FORMAT " MB heap).",
1209 max_live_bytes/M, _g1->capacity()/M);
1210 }
1212 // The important thing about this is that it includes "os::elapsedTime".
1213 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
1214 double end_time_sec = os::elapsedTime();
1215 double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
1216 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1217 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1218 _prev_collection_pause_end_ms += elapsed_time_ms;
1220 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
1222 _num_markings++;
1224 // We did a marking, so reset the "since_last_mark" variables.
1225 double considerConcMarkCost = 1.0;
1226 // If there are available processors, concurrent activity is free...
1227 if (Threads::number_of_non_daemon_threads() * 2 <
1228 os::active_processor_count()) {
1229 considerConcMarkCost = 0.0;
1230 }
1231 _n_pauses_at_mark_end = _n_pauses;
1232 _n_marks_since_last_pause++;
1233 _conc_mark_initiated = false;
1234 }
1236 void
1237 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
1238 if (in_young_gc_mode()) {
1239 _should_revert_to_full_young_gcs = false;
1240 _last_full_young_gc = true;
1241 _in_marking_window = false;
1242 if (adaptive_young_list_length())
1243 calculate_young_list_target_config();
1244 }
1245 }
1247 void G1CollectorPolicy::record_concurrent_pause() {
1248 if (_stop_world_start > 0.0) {
1249 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
1250 _all_yield_times_ms->add(yield_ms);
1251 }
1252 }
1254 void G1CollectorPolicy::record_concurrent_pause_end() {
1255 }
1257 void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() {
1258 _cur_CH_strong_roots_end_sec = os::elapsedTime();
1259 _cur_CH_strong_roots_dur_ms =
1260 (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0;
1261 }
1263 void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() {
1264 _cur_G1_strong_roots_end_sec = os::elapsedTime();
1265 _cur_G1_strong_roots_dur_ms =
1266 (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0;
1267 }
1269 template<class T>
1270 T sum_of(T* sum_arr, int start, int n, int N) {
1271 T sum = (T)0;
1272 for (int i = 0; i < n; i++) {
1273 int j = (start + i) % N;
1274 sum += sum_arr[j];
1275 }
1276 return sum;
1277 }
1279 void G1CollectorPolicy::print_par_stats (int level,
1280 const char* str,
1281 double* data,
1282 bool summary) {
1283 double min = data[0], max = data[0];
1284 double total = 0.0;
1285 int j;
1286 for (j = 0; j < level; ++j)
1287 gclog_or_tty->print(" ");
1288 gclog_or_tty->print("[%s (ms):", str);
1289 for (uint i = 0; i < ParallelGCThreads; ++i) {
1290 double val = data[i];
1291 if (val < min)
1292 min = val;
1293 if (val > max)
1294 max = val;
1295 total += val;
1296 gclog_or_tty->print(" %3.1lf", val);
1297 }
1298 if (summary) {
1299 gclog_or_tty->print_cr("");
1300 double avg = total / (double) ParallelGCThreads;
1301 gclog_or_tty->print(" ");
1302 for (j = 0; j < level; ++j)
1303 gclog_or_tty->print(" ");
1304 gclog_or_tty->print("Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf",
1305 avg, min, max);
1306 }
1307 gclog_or_tty->print_cr("]");
1308 }
1310 void G1CollectorPolicy::print_par_buffers (int level,
1311 const char* str,
1312 double* data,
1313 bool summary) {
1314 double min = data[0], max = data[0];
1315 double total = 0.0;
1316 int j;
1317 for (j = 0; j < level; ++j)
1318 gclog_or_tty->print(" ");
1319 gclog_or_tty->print("[%s :", str);
1320 for (uint i = 0; i < ParallelGCThreads; ++i) {
1321 double val = data[i];
1322 if (val < min)
1323 min = val;
1324 if (val > max)
1325 max = val;
1326 total += val;
1327 gclog_or_tty->print(" %d", (int) val);
1328 }
1329 if (summary) {
1330 gclog_or_tty->print_cr("");
1331 double avg = total / (double) ParallelGCThreads;
1332 gclog_or_tty->print(" ");
1333 for (j = 0; j < level; ++j)
1334 gclog_or_tty->print(" ");
1335 gclog_or_tty->print("Sum: %d, Avg: %d, Min: %d, Max: %d",
1336 (int)total, (int)avg, (int)min, (int)max);
1337 }
1338 gclog_or_tty->print_cr("]");
1339 }
1341 void G1CollectorPolicy::print_stats (int level,
1342 const char* str,
1343 double value) {
1344 for (int j = 0; j < level; ++j)
1345 gclog_or_tty->print(" ");
1346 gclog_or_tty->print_cr("[%s: %5.1lf ms]", str, value);
1347 }
1349 void G1CollectorPolicy::print_stats (int level,
1350 const char* str,
1351 int value) {
1352 for (int j = 0; j < level; ++j)
1353 gclog_or_tty->print(" ");
1354 gclog_or_tty->print_cr("[%s: %d]", str, value);
1355 }
1357 double G1CollectorPolicy::avg_value (double* data) {
1358 if (ParallelGCThreads > 0) {
1359 double ret = 0.0;
1360 for (uint i = 0; i < ParallelGCThreads; ++i)
1361 ret += data[i];
1362 return ret / (double) ParallelGCThreads;
1363 } else {
1364 return data[0];
1365 }
1366 }
1368 double G1CollectorPolicy::max_value (double* data) {
1369 if (ParallelGCThreads > 0) {
1370 double ret = data[0];
1371 for (uint i = 1; i < ParallelGCThreads; ++i)
1372 if (data[i] > ret)
1373 ret = data[i];
1374 return ret;
1375 } else {
1376 return data[0];
1377 }
1378 }
1380 double G1CollectorPolicy::sum_of_values (double* data) {
1381 if (ParallelGCThreads > 0) {
1382 double sum = 0.0;
1383 for (uint i = 0; i < ParallelGCThreads; i++)
1384 sum += data[i];
1385 return sum;
1386 } else {
1387 return data[0];
1388 }
1389 }
1391 double G1CollectorPolicy::max_sum (double* data1,
1392 double* data2) {
1393 double ret = data1[0] + data2[0];
1395 if (ParallelGCThreads > 0) {
1396 for (uint i = 1; i < ParallelGCThreads; ++i) {
1397 double data = data1[i] + data2[i];
1398 if (data > ret)
1399 ret = data;
1400 }
1401 }
1402 return ret;
1403 }
1405 // Anything below that is considered to be zero
1406 #define MIN_TIMER_GRANULARITY 0.0000001
1408 void G1CollectorPolicy::record_collection_pause_end(bool abandoned) {
1409 double end_time_sec = os::elapsedTime();
1410 double elapsed_ms = _last_pause_time_ms;
1411 bool parallel = ParallelGCThreads > 0;
1412 double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0;
1413 size_t rs_size =
1414 _cur_collection_pause_used_regions_at_start - collection_set_size();
1415 size_t cur_used_bytes = _g1->used();
1416 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1417 bool last_pause_included_initial_mark = false;
1418 bool update_stats = !abandoned && !_g1->evacuation_failed();
1420 #ifndef PRODUCT
1421 if (G1YoungSurvRateVerbose) {
1422 gclog_or_tty->print_cr("");
1423 _short_lived_surv_rate_group->print();
1424 // do that for any other surv rate groups too
1425 }
1426 #endif // PRODUCT
1428 if (in_young_gc_mode()) {
1429 last_pause_included_initial_mark = _should_initiate_conc_mark;
1430 if (last_pause_included_initial_mark)
1431 record_concurrent_mark_init_end_pre(0.0);
1433 size_t min_used_targ =
1434 (_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta);
1436 if (cur_used_bytes > min_used_targ) {
1437 if (cur_used_bytes <= _prev_collection_pause_used_at_end_bytes) {
1438 } else if (!_g1->mark_in_progress() && !_last_full_young_gc) {
1439 _should_initiate_conc_mark = true;
1440 }
1441 }
1443 _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
1444 }
1446 _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
1447 end_time_sec, false);
1449 guarantee(_cur_collection_pause_used_regions_at_start >=
1450 collection_set_size(),
1451 "Negative RS size?");
1453 // This assert is exempted when we're doing parallel collection pauses,
1454 // because the fragmentation caused by the parallel GC allocation buffers
1455 // can lead to more memory being used during collection than was used
1456 // before. Best leave this out until the fragmentation problem is fixed.
1457 // Pauses in which evacuation failed can also lead to negative
1458 // collections, since no space is reclaimed from a region containing an
1459 // object whose evacuation failed.
1460 // Further, we're now always doing parallel collection. But I'm still
1461 // leaving this here as a placeholder for a more precise assertion later.
1462 // (DLD, 10/05.)
1463 assert((true || parallel) // Always using GC LABs now.
1464 || _g1->evacuation_failed()
1465 || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
1466 "Negative collection");
1468 size_t freed_bytes =
1469 _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
1470 size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
1471 double survival_fraction =
1472 (double)surviving_bytes/
1473 (double)_collection_set_bytes_used_before;
1475 _n_pauses++;
1477 if (update_stats) {
1478 _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms);
1479 _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms);
1480 _recent_evac_times_ms->add(evac_ms);
1481 _recent_pause_times_ms->add(elapsed_ms);
1483 _recent_rs_sizes->add(rs_size);
1485 // We exempt parallel collection from this check because Alloc Buffer
1486 // fragmentation can produce negative collections. Same with evac
1487 // failure.
1488 // Further, we're now always doing parallel collection. But I'm still
1489 // leaving this here as a placeholder for a more precise assertion later.
1490 // (DLD, 10/05.
1491 assert((true || parallel)
1492 || _g1->evacuation_failed()
1493 || surviving_bytes <= _collection_set_bytes_used_before,
1494 "Or else negative collection!");
1495 _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
1496 _recent_CS_bytes_surviving->add(surviving_bytes);
1498 // this is where we update the allocation rate of the application
1499 double app_time_ms =
1500 (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
1501 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1502 // This usually happens due to the timer not having the required
1503 // granularity. Some Linuxes are the usual culprits.
1504 // We'll just set it to something (arbitrarily) small.
1505 app_time_ms = 1.0;
1506 }
1507 size_t regions_allocated =
1508 (_region_num_young - _prev_region_num_young) +
1509 (_region_num_tenured - _prev_region_num_tenured);
1510 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1511 _alloc_rate_ms_seq->add(alloc_rate_ms);
1512 _prev_region_num_young = _region_num_young;
1513 _prev_region_num_tenured = _region_num_tenured;
1515 double interval_ms =
1516 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1517 update_recent_gc_times(end_time_sec, elapsed_ms);
1518 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1519 // using 1.01 to account for floating point inaccuracies
1520 assert(recent_avg_pause_time_ratio() < 1.01, "All GC?");
1521 }
1523 if (G1PolicyVerbose > 1) {
1524 gclog_or_tty->print_cr(" Recording collection pause(%d)", _n_pauses);
1525 }
1527 PauseSummary* summary;
1528 if (abandoned) {
1529 summary = _abandoned_summary;
1530 } else {
1531 summary = _summary;
1532 }
1534 double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
1535 double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
1536 double scan_only_time = avg_value(_par_last_scan_only_times_ms);
1537 double scan_only_regions_scanned =
1538 sum_of_values(_par_last_scan_only_regions_scanned);
1539 double update_rs_time = avg_value(_par_last_update_rs_times_ms);
1540 double update_rs_processed_buffers =
1541 sum_of_values(_par_last_update_rs_processed_buffers);
1542 double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
1543 double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
1544 double termination_time = avg_value(_par_last_termination_times_ms);
1546 double parallel_other_time = _cur_collection_par_time_ms -
1547 (update_rs_time + ext_root_scan_time + mark_stack_scan_time +
1548 scan_only_time + scan_rs_time + obj_copy_time + termination_time);
1549 if (update_stats) {
1550 MainBodySummary* body_summary = summary->main_body_summary();
1551 guarantee(body_summary != NULL, "should not be null!");
1553 if (_satb_drain_time_set)
1554 body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
1555 else
1556 body_summary->record_satb_drain_time_ms(0.0);
1557 body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
1558 body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
1559 body_summary->record_scan_only_time_ms(scan_only_time);
1560 body_summary->record_update_rs_time_ms(update_rs_time);
1561 body_summary->record_scan_rs_time_ms(scan_rs_time);
1562 body_summary->record_obj_copy_time_ms(obj_copy_time);
1563 if (parallel) {
1564 body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
1565 body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
1566 body_summary->record_termination_time_ms(termination_time);
1567 body_summary->record_parallel_other_time_ms(parallel_other_time);
1568 }
1569 body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
1570 }
1572 if (G1PolicyVerbose > 1) {
1573 gclog_or_tty->print_cr(" ET: %10.6f ms (avg: %10.6f ms)\n"
1574 " CH Strong: %10.6f ms (avg: %10.6f ms)\n"
1575 " G1 Strong: %10.6f ms (avg: %10.6f ms)\n"
1576 " Evac: %10.6f ms (avg: %10.6f ms)\n"
1577 " ET-RS: %10.6f ms (avg: %10.6f ms)\n"
1578 " |RS|: " SIZE_FORMAT,
1579 elapsed_ms, recent_avg_time_for_pauses_ms(),
1580 _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(),
1581 _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(),
1582 evac_ms, recent_avg_time_for_evac_ms(),
1583 scan_rs_time,
1584 recent_avg_time_for_pauses_ms() -
1585 recent_avg_time_for_G1_strong_ms(),
1586 rs_size);
1588 gclog_or_tty->print_cr(" Used at start: " SIZE_FORMAT"K"
1589 " At end " SIZE_FORMAT "K\n"
1590 " garbage : " SIZE_FORMAT "K"
1591 " of " SIZE_FORMAT "K\n"
1592 " survival : %6.2f%% (%6.2f%% avg)",
1593 _cur_collection_pause_used_at_start_bytes/K,
1594 _g1->used()/K, freed_bytes/K,
1595 _collection_set_bytes_used_before/K,
1596 survival_fraction*100.0,
1597 recent_avg_survival_fraction()*100.0);
1598 gclog_or_tty->print_cr(" Recent %% gc pause time: %6.2f",
1599 recent_avg_pause_time_ratio() * 100.0);
1600 }
1602 double other_time_ms = elapsed_ms;
1604 if (!abandoned) {
1605 if (_satb_drain_time_set)
1606 other_time_ms -= _cur_satb_drain_time_ms;
1608 if (parallel)
1609 other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
1610 else
1611 other_time_ms -=
1612 update_rs_time +
1613 ext_root_scan_time + mark_stack_scan_time + scan_only_time +
1614 scan_rs_time + obj_copy_time;
1615 }
1617 if (PrintGCDetails) {
1618 gclog_or_tty->print_cr("%s%s, %1.8lf secs]",
1619 abandoned ? " (abandoned)" : "",
1620 (last_pause_included_initial_mark) ? " (initial-mark)" : "",
1621 elapsed_ms / 1000.0);
1623 if (!abandoned) {
1624 if (_satb_drain_time_set) {
1625 print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
1626 }
1627 if (_last_satb_drain_processed_buffers >= 0) {
1628 print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
1629 }
1630 if (parallel) {
1631 print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
1632 print_par_stats(2, "Update RS (Start)", _par_last_update_rs_start_times_ms, false);
1633 print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
1634 print_par_buffers(3, "Processed Buffers",
1635 _par_last_update_rs_processed_buffers, true);
1636 print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
1637 print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
1638 print_par_stats(2, "Scan-Only Scanning", _par_last_scan_only_times_ms);
1639 print_par_buffers(3, "Scan-Only Regions",
1640 _par_last_scan_only_regions_scanned, true);
1641 print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
1642 print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
1643 print_par_stats(2, "Termination", _par_last_termination_times_ms);
1644 print_stats(2, "Other", parallel_other_time);
1645 print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
1646 } else {
1647 print_stats(1, "Update RS", update_rs_time);
1648 print_stats(2, "Processed Buffers",
1649 (int)update_rs_processed_buffers);
1650 print_stats(1, "Ext Root Scanning", ext_root_scan_time);
1651 print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
1652 print_stats(1, "Scan-Only Scanning", scan_only_time);
1653 print_stats(1, "Scan RS", scan_rs_time);
1654 print_stats(1, "Object Copying", obj_copy_time);
1655 }
1656 }
1657 #ifndef PRODUCT
1658 print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
1659 print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
1660 print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
1661 print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
1662 if (_num_cc_clears > 0) {
1663 print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
1664 }
1665 #endif
1666 print_stats(1, "Other", other_time_ms);
1667 for (int i = 0; i < _aux_num; ++i) {
1668 if (_cur_aux_times_set[i]) {
1669 char buffer[96];
1670 sprintf(buffer, "Aux%d", i);
1671 print_stats(1, buffer, _cur_aux_times_ms[i]);
1672 }
1673 }
1674 }
1675 if (PrintGCDetails)
1676 gclog_or_tty->print(" [");
1677 if (PrintGC || PrintGCDetails)
1678 _g1->print_size_transition(gclog_or_tty,
1679 _cur_collection_pause_used_at_start_bytes,
1680 _g1->used(), _g1->capacity());
1681 if (PrintGCDetails)
1682 gclog_or_tty->print_cr("]");
1684 _all_pause_times_ms->add(elapsed_ms);
1685 if (update_stats) {
1686 summary->record_total_time_ms(elapsed_ms);
1687 summary->record_other_time_ms(other_time_ms);
1688 }
1689 for (int i = 0; i < _aux_num; ++i)
1690 if (_cur_aux_times_set[i])
1691 _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
1693 // Reset marks-between-pauses counter.
1694 _n_marks_since_last_pause = 0;
1696 // Update the efficiency-since-mark vars.
1697 double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
1698 if (elapsed_ms < MIN_TIMER_GRANULARITY) {
1699 // This usually happens due to the timer not having the required
1700 // granularity. Some Linuxes are the usual culprits.
1701 // We'll just set it to something (arbitrarily) small.
1702 proc_ms = 1.0;
1703 }
1704 double cur_efficiency = (double) freed_bytes / proc_ms;
1706 bool new_in_marking_window = _in_marking_window;
1707 bool new_in_marking_window_im = false;
1708 if (_should_initiate_conc_mark) {
1709 new_in_marking_window = true;
1710 new_in_marking_window_im = true;
1711 }
1713 if (in_young_gc_mode()) {
1714 if (_last_full_young_gc) {
1715 set_full_young_gcs(false);
1716 _last_full_young_gc = false;
1717 }
1719 if ( !_last_young_gc_full ) {
1720 if ( _should_revert_to_full_young_gcs ||
1721 _known_garbage_ratio < 0.05 ||
1722 (adaptive_young_list_length() &&
1723 (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) {
1724 set_full_young_gcs(true);
1725 }
1726 }
1727 _should_revert_to_full_young_gcs = false;
1729 if (_last_young_gc_full && !_during_marking)
1730 _young_gc_eff_seq->add(cur_efficiency);
1731 }
1733 _short_lived_surv_rate_group->start_adding_regions();
1734 // do that for any other surv rate groupsx
1736 // <NEW PREDICTION>
1738 if (update_stats) {
1739 double pause_time_ms = elapsed_ms;
1741 size_t diff = 0;
1742 if (_max_pending_cards >= _pending_cards)
1743 diff = _max_pending_cards - _pending_cards;
1744 _pending_card_diff_seq->add((double) diff);
1746 double cost_per_card_ms = 0.0;
1747 if (_pending_cards > 0) {
1748 cost_per_card_ms = update_rs_time / (double) _pending_cards;
1749 _cost_per_card_ms_seq->add(cost_per_card_ms);
1750 }
1752 double cost_per_scan_only_region_ms = 0.0;
1753 if (scan_only_regions_scanned > 0.0) {
1754 cost_per_scan_only_region_ms =
1755 scan_only_time / scan_only_regions_scanned;
1756 if (_in_marking_window_im)
1757 _cost_per_scan_only_region_ms_during_cm_seq->add(cost_per_scan_only_region_ms);
1758 else
1759 _cost_per_scan_only_region_ms_seq->add(cost_per_scan_only_region_ms);
1760 }
1762 size_t cards_scanned = _g1->cards_scanned();
1764 double cost_per_entry_ms = 0.0;
1765 if (cards_scanned > 10) {
1766 cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
1767 if (_last_young_gc_full)
1768 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1769 else
1770 _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1771 }
1773 if (_max_rs_lengths > 0) {
1774 double cards_per_entry_ratio =
1775 (double) cards_scanned / (double) _max_rs_lengths;
1776 if (_last_young_gc_full)
1777 _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1778 else
1779 _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1780 }
1782 size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1783 if (rs_length_diff >= 0)
1784 _rs_length_diff_seq->add((double) rs_length_diff);
1786 size_t copied_bytes = surviving_bytes;
1787 double cost_per_byte_ms = 0.0;
1788 if (copied_bytes > 0) {
1789 cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
1790 if (_in_marking_window)
1791 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1792 else
1793 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1794 }
1796 double all_other_time_ms = pause_time_ms -
1797 (update_rs_time + scan_only_time + scan_rs_time + obj_copy_time +
1798 _mark_closure_time_ms + termination_time);
1800 double young_other_time_ms = 0.0;
1801 if (_recorded_young_regions > 0) {
1802 young_other_time_ms =
1803 _recorded_young_cset_choice_time_ms +
1804 _recorded_young_free_cset_time_ms;
1805 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1806 (double) _recorded_young_regions);
1807 }
1808 double non_young_other_time_ms = 0.0;
1809 if (_recorded_non_young_regions > 0) {
1810 non_young_other_time_ms =
1811 _recorded_non_young_cset_choice_time_ms +
1812 _recorded_non_young_free_cset_time_ms;
1814 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1815 (double) _recorded_non_young_regions);
1816 }
1818 double constant_other_time_ms = all_other_time_ms -
1819 (young_other_time_ms + non_young_other_time_ms);
1820 _constant_other_time_ms_seq->add(constant_other_time_ms);
1822 double survival_ratio = 0.0;
1823 if (_bytes_in_collection_set_before_gc > 0) {
1824 survival_ratio = (double) bytes_in_to_space_during_gc() /
1825 (double) _bytes_in_collection_set_before_gc;
1826 }
1828 _pending_cards_seq->add((double) _pending_cards);
1829 _scanned_cards_seq->add((double) cards_scanned);
1830 _rs_lengths_seq->add((double) _max_rs_lengths);
1832 double expensive_region_limit_ms =
1833 (double) MaxGCPauseMillis - predict_constant_other_time_ms();
1834 if (expensive_region_limit_ms < 0.0) {
1835 // this means that the other time was predicted to be longer than
1836 // than the max pause time
1837 expensive_region_limit_ms = (double) MaxGCPauseMillis;
1838 }
1839 _expensive_region_limit_ms = expensive_region_limit_ms;
1841 if (PREDICTIONS_VERBOSE) {
1842 gclog_or_tty->print_cr("");
1843 gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
1844 "REGIONS %d %d %d %d "
1845 "PENDING_CARDS %d %d "
1846 "CARDS_SCANNED %d %d "
1847 "RS_LENGTHS %d %d "
1848 "SCAN_ONLY_SCAN %1.6lf %1.6lf "
1849 "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
1850 "SURVIVAL_RATIO %1.6lf %1.6lf "
1851 "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
1852 "OTHER_YOUNG %1.6lf %1.6lf "
1853 "OTHER_NON_YOUNG %1.6lf %1.6lf "
1854 "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
1855 "ELAPSED %1.6lf %1.6lf ",
1856 _cur_collection_start_sec,
1857 (!_last_young_gc_full) ? 2 :
1858 (last_pause_included_initial_mark) ? 1 : 0,
1859 _recorded_region_num,
1860 _recorded_young_regions,
1861 _recorded_scan_only_regions,
1862 _recorded_non_young_regions,
1863 _predicted_pending_cards, _pending_cards,
1864 _predicted_cards_scanned, cards_scanned,
1865 _predicted_rs_lengths, _max_rs_lengths,
1866 _predicted_scan_only_scan_time_ms, scan_only_time,
1867 _predicted_rs_update_time_ms, update_rs_time,
1868 _predicted_rs_scan_time_ms, scan_rs_time,
1869 _predicted_survival_ratio, survival_ratio,
1870 _predicted_object_copy_time_ms, obj_copy_time,
1871 _predicted_constant_other_time_ms, constant_other_time_ms,
1872 _predicted_young_other_time_ms, young_other_time_ms,
1873 _predicted_non_young_other_time_ms,
1874 non_young_other_time_ms,
1875 _vtime_diff_ms, termination_time,
1876 _predicted_pause_time_ms, elapsed_ms);
1877 }
1879 if (G1PolicyVerbose > 0) {
1880 gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
1881 _predicted_pause_time_ms,
1882 (_within_target) ? "within" : "outside",
1883 elapsed_ms);
1884 }
1886 }
1888 _in_marking_window = new_in_marking_window;
1889 _in_marking_window_im = new_in_marking_window_im;
1890 _free_regions_at_end_of_collection = _g1->free_regions();
1891 _scan_only_regions_at_end_of_collection = _g1->young_list_length();
1892 calculate_young_list_min_length();
1893 calculate_young_list_target_config();
1895 // </NEW PREDICTION>
1897 _target_pause_time_ms = -1.0;
1898 }
1900 // <NEW PREDICTION>
1902 double
1903 G1CollectorPolicy::
1904 predict_young_collection_elapsed_time_ms(size_t adjustment) {
1905 guarantee( adjustment == 0 || adjustment == 1, "invariant" );
1907 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1908 size_t young_num = g1h->young_list_length();
1909 if (young_num == 0)
1910 return 0.0;
1912 young_num += adjustment;
1913 size_t pending_cards = predict_pending_cards();
1914 size_t rs_lengths = g1h->young_list_sampled_rs_lengths() +
1915 predict_rs_length_diff();
1916 size_t card_num;
1917 if (full_young_gcs())
1918 card_num = predict_young_card_num(rs_lengths);
1919 else
1920 card_num = predict_non_young_card_num(rs_lengths);
1921 size_t young_byte_size = young_num * HeapRegion::GrainBytes;
1922 double accum_yg_surv_rate =
1923 _short_lived_surv_rate_group->accum_surv_rate(adjustment);
1925 size_t bytes_to_copy =
1926 (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
1928 return
1929 predict_rs_update_time_ms(pending_cards) +
1930 predict_rs_scan_time_ms(card_num) +
1931 predict_object_copy_time_ms(bytes_to_copy) +
1932 predict_young_other_time_ms(young_num) +
1933 predict_constant_other_time_ms();
1934 }
1936 double
1937 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1938 size_t rs_length = predict_rs_length_diff();
1939 size_t card_num;
1940 if (full_young_gcs())
1941 card_num = predict_young_card_num(rs_length);
1942 else
1943 card_num = predict_non_young_card_num(rs_length);
1944 return predict_base_elapsed_time_ms(pending_cards, card_num);
1945 }
1947 double
1948 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1949 size_t scanned_cards) {
1950 return
1951 predict_rs_update_time_ms(pending_cards) +
1952 predict_rs_scan_time_ms(scanned_cards) +
1953 predict_constant_other_time_ms();
1954 }
1956 double
1957 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1958 bool young) {
1959 size_t rs_length = hr->rem_set()->occupied();
1960 size_t card_num;
1961 if (full_young_gcs())
1962 card_num = predict_young_card_num(rs_length);
1963 else
1964 card_num = predict_non_young_card_num(rs_length);
1965 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1967 double region_elapsed_time_ms =
1968 predict_rs_scan_time_ms(card_num) +
1969 predict_object_copy_time_ms(bytes_to_copy);
1971 if (young)
1972 region_elapsed_time_ms += predict_young_other_time_ms(1);
1973 else
1974 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1976 return region_elapsed_time_ms;
1977 }
1979 size_t
1980 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1981 size_t bytes_to_copy;
1982 if (hr->is_marked())
1983 bytes_to_copy = hr->max_live_bytes();
1984 else {
1985 guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
1986 "invariant" );
1987 int age = hr->age_in_surv_rate_group();
1988 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1989 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1990 }
1992 return bytes_to_copy;
1993 }
1995 void
1996 G1CollectorPolicy::start_recording_regions() {
1997 _recorded_rs_lengths = 0;
1998 _recorded_scan_only_regions = 0;
1999 _recorded_young_regions = 0;
2000 _recorded_non_young_regions = 0;
2002 #if PREDICTIONS_VERBOSE
2003 _predicted_rs_lengths = 0;
2004 _predicted_cards_scanned = 0;
2006 _recorded_marked_bytes = 0;
2007 _recorded_young_bytes = 0;
2008 _predicted_bytes_to_copy = 0;
2009 #endif // PREDICTIONS_VERBOSE
2010 }
2012 void
2013 G1CollectorPolicy::record_cset_region(HeapRegion* hr, bool young) {
2014 if (young) {
2015 ++_recorded_young_regions;
2016 } else {
2017 ++_recorded_non_young_regions;
2018 }
2019 #if PREDICTIONS_VERBOSE
2020 if (young) {
2021 _recorded_young_bytes += hr->used();
2022 } else {
2023 _recorded_marked_bytes += hr->max_live_bytes();
2024 }
2025 _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
2026 #endif // PREDICTIONS_VERBOSE
2028 size_t rs_length = hr->rem_set()->occupied();
2029 _recorded_rs_lengths += rs_length;
2030 }
2032 void
2033 G1CollectorPolicy::record_scan_only_regions(size_t scan_only_length) {
2034 _recorded_scan_only_regions = scan_only_length;
2035 }
2037 void
2038 G1CollectorPolicy::end_recording_regions() {
2039 #if PREDICTIONS_VERBOSE
2040 _predicted_pending_cards = predict_pending_cards();
2041 _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
2042 if (full_young_gcs())
2043 _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
2044 else
2045 _predicted_cards_scanned +=
2046 predict_non_young_card_num(_predicted_rs_lengths);
2047 _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
2049 _predicted_scan_only_scan_time_ms =
2050 predict_scan_only_time_ms(_recorded_scan_only_regions);
2051 _predicted_rs_update_time_ms =
2052 predict_rs_update_time_ms(_g1->pending_card_num());
2053 _predicted_rs_scan_time_ms =
2054 predict_rs_scan_time_ms(_predicted_cards_scanned);
2055 _predicted_object_copy_time_ms =
2056 predict_object_copy_time_ms(_predicted_bytes_to_copy);
2057 _predicted_constant_other_time_ms =
2058 predict_constant_other_time_ms();
2059 _predicted_young_other_time_ms =
2060 predict_young_other_time_ms(_recorded_young_regions);
2061 _predicted_non_young_other_time_ms =
2062 predict_non_young_other_time_ms(_recorded_non_young_regions);
2064 _predicted_pause_time_ms =
2065 _predicted_scan_only_scan_time_ms +
2066 _predicted_rs_update_time_ms +
2067 _predicted_rs_scan_time_ms +
2068 _predicted_object_copy_time_ms +
2069 _predicted_constant_other_time_ms +
2070 _predicted_young_other_time_ms +
2071 _predicted_non_young_other_time_ms;
2072 #endif // PREDICTIONS_VERBOSE
2073 }
2075 void G1CollectorPolicy::check_if_region_is_too_expensive(double
2076 predicted_time_ms) {
2077 // I don't think we need to do this when in young GC mode since
2078 // marking will be initiated next time we hit the soft limit anyway...
2079 if (predicted_time_ms > _expensive_region_limit_ms) {
2080 if (!in_young_gc_mode()) {
2081 set_full_young_gcs(true);
2082 _should_initiate_conc_mark = true;
2083 } else
2084 // no point in doing another partial one
2085 _should_revert_to_full_young_gcs = true;
2086 }
2087 }
2089 // </NEW PREDICTION>
2092 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
2093 double elapsed_ms) {
2094 _recent_gc_times_ms->add(elapsed_ms);
2095 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
2096 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
2097 }
2099 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
2100 if (_recent_pause_times_ms->num() == 0) return (double) MaxGCPauseMillis;
2101 else return _recent_pause_times_ms->avg();
2102 }
2104 double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() {
2105 if (_recent_CH_strong_roots_times_ms->num() == 0)
2106 return (double)MaxGCPauseMillis/3.0;
2107 else return _recent_CH_strong_roots_times_ms->avg();
2108 }
2110 double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() {
2111 if (_recent_G1_strong_roots_times_ms->num() == 0)
2112 return (double)MaxGCPauseMillis/3.0;
2113 else return _recent_G1_strong_roots_times_ms->avg();
2114 }
2116 double G1CollectorPolicy::recent_avg_time_for_evac_ms() {
2117 if (_recent_evac_times_ms->num() == 0) return (double)MaxGCPauseMillis/3.0;
2118 else return _recent_evac_times_ms->avg();
2119 }
2121 int G1CollectorPolicy::number_of_recent_gcs() {
2122 assert(_recent_CH_strong_roots_times_ms->num() ==
2123 _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync");
2124 assert(_recent_G1_strong_roots_times_ms->num() ==
2125 _recent_evac_times_ms->num(), "Sequence out of sync");
2126 assert(_recent_evac_times_ms->num() ==
2127 _recent_pause_times_ms->num(), "Sequence out of sync");
2128 assert(_recent_pause_times_ms->num() ==
2129 _recent_CS_bytes_used_before->num(), "Sequence out of sync");
2130 assert(_recent_CS_bytes_used_before->num() ==
2131 _recent_CS_bytes_surviving->num(), "Sequence out of sync");
2132 return _recent_pause_times_ms->num();
2133 }
2135 double G1CollectorPolicy::recent_avg_survival_fraction() {
2136 return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
2137 _recent_CS_bytes_used_before);
2138 }
2140 double G1CollectorPolicy::last_survival_fraction() {
2141 return last_survival_fraction_work(_recent_CS_bytes_surviving,
2142 _recent_CS_bytes_used_before);
2143 }
2145 double
2146 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
2147 TruncatedSeq* before) {
2148 assert(surviving->num() == before->num(), "Sequence out of sync");
2149 if (before->sum() > 0.0) {
2150 double recent_survival_rate = surviving->sum() / before->sum();
2151 // We exempt parallel collection from this check because Alloc Buffer
2152 // fragmentation can produce negative collections.
2153 // Further, we're now always doing parallel collection. But I'm still
2154 // leaving this here as a placeholder for a more precise assertion later.
2155 // (DLD, 10/05.)
2156 assert((true || ParallelGCThreads > 0) ||
2157 _g1->evacuation_failed() ||
2158 recent_survival_rate <= 1.0, "Or bad frac");
2159 return recent_survival_rate;
2160 } else {
2161 return 1.0; // Be conservative.
2162 }
2163 }
2165 double
2166 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
2167 TruncatedSeq* before) {
2168 assert(surviving->num() == before->num(), "Sequence out of sync");
2169 if (surviving->num() > 0 && before->last() > 0.0) {
2170 double last_survival_rate = surviving->last() / before->last();
2171 // We exempt parallel collection from this check because Alloc Buffer
2172 // fragmentation can produce negative collections.
2173 // Further, we're now always doing parallel collection. But I'm still
2174 // leaving this here as a placeholder for a more precise assertion later.
2175 // (DLD, 10/05.)
2176 assert((true || ParallelGCThreads > 0) ||
2177 last_survival_rate <= 1.0, "Or bad frac");
2178 return last_survival_rate;
2179 } else {
2180 return 1.0;
2181 }
2182 }
2184 static const int survival_min_obs = 5;
2185 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
2186 static const double min_survival_rate = 0.1;
2188 double
2189 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
2190 double latest) {
2191 double res = avg;
2192 if (number_of_recent_gcs() < survival_min_obs) {
2193 res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
2194 }
2195 res = MAX2(res, latest);
2196 res = MAX2(res, min_survival_rate);
2197 // In the parallel case, LAB fragmentation can produce "negative
2198 // collections"; so can evac failure. Cap at 1.0
2199 res = MIN2(res, 1.0);
2200 return res;
2201 }
2203 size_t G1CollectorPolicy::expansion_amount() {
2204 if ((int)(recent_avg_pause_time_ratio() * 100.0) > G1GCPercent) {
2205 // We will double the existing space, or take
2206 // G1ExpandByPercentOfAvailable % of the available expansion
2207 // space, whichever is smaller, bounded below by a minimum
2208 // expansion (unless that's all that's left.)
2209 const size_t min_expand_bytes = 1*M;
2210 size_t reserved_bytes = _g1->g1_reserved_obj_bytes();
2211 size_t committed_bytes = _g1->capacity();
2212 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
2213 size_t expand_bytes;
2214 size_t expand_bytes_via_pct =
2215 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
2216 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
2217 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
2218 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
2219 if (G1PolicyVerbose > 1) {
2220 gclog_or_tty->print("Decided to expand: ratio = %5.2f, "
2221 "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n"
2222 " Answer = %d.\n",
2223 recent_avg_pause_time_ratio(),
2224 byte_size_in_proper_unit(committed_bytes),
2225 proper_unit_for_byte_size(committed_bytes),
2226 byte_size_in_proper_unit(uncommitted_bytes),
2227 proper_unit_for_byte_size(uncommitted_bytes),
2228 byte_size_in_proper_unit(expand_bytes_via_pct),
2229 proper_unit_for_byte_size(expand_bytes_via_pct),
2230 byte_size_in_proper_unit(expand_bytes),
2231 proper_unit_for_byte_size(expand_bytes));
2232 }
2233 return expand_bytes;
2234 } else {
2235 return 0;
2236 }
2237 }
2239 void G1CollectorPolicy::note_start_of_mark_thread() {
2240 _mark_thread_startup_sec = os::elapsedTime();
2241 }
2243 class CountCSClosure: public HeapRegionClosure {
2244 G1CollectorPolicy* _g1_policy;
2245 public:
2246 CountCSClosure(G1CollectorPolicy* g1_policy) :
2247 _g1_policy(g1_policy) {}
2248 bool doHeapRegion(HeapRegion* r) {
2249 _g1_policy->_bytes_in_collection_set_before_gc += r->used();
2250 return false;
2251 }
2252 };
2254 void G1CollectorPolicy::count_CS_bytes_used() {
2255 CountCSClosure cs_closure(this);
2256 _g1->collection_set_iterate(&cs_closure);
2257 }
2259 static void print_indent(int level) {
2260 for (int j = 0; j < level+1; ++j)
2261 gclog_or_tty->print(" ");
2262 }
2264 void G1CollectorPolicy::print_summary (int level,
2265 const char* str,
2266 NumberSeq* seq) const {
2267 double sum = seq->sum();
2268 print_indent(level);
2269 gclog_or_tty->print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
2270 str, sum / 1000.0, seq->avg());
2271 }
2273 void G1CollectorPolicy::print_summary_sd (int level,
2274 const char* str,
2275 NumberSeq* seq) const {
2276 print_summary(level, str, seq);
2277 print_indent(level + 5);
2278 gclog_or_tty->print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2279 seq->num(), seq->sd(), seq->maximum());
2280 }
2282 void G1CollectorPolicy::check_other_times(int level,
2283 NumberSeq* other_times_ms,
2284 NumberSeq* calc_other_times_ms) const {
2285 bool should_print = false;
2287 double max_sum = MAX2(fabs(other_times_ms->sum()),
2288 fabs(calc_other_times_ms->sum()));
2289 double min_sum = MIN2(fabs(other_times_ms->sum()),
2290 fabs(calc_other_times_ms->sum()));
2291 double sum_ratio = max_sum / min_sum;
2292 if (sum_ratio > 1.1) {
2293 should_print = true;
2294 print_indent(level + 1);
2295 gclog_or_tty->print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
2296 }
2298 double max_avg = MAX2(fabs(other_times_ms->avg()),
2299 fabs(calc_other_times_ms->avg()));
2300 double min_avg = MIN2(fabs(other_times_ms->avg()),
2301 fabs(calc_other_times_ms->avg()));
2302 double avg_ratio = max_avg / min_avg;
2303 if (avg_ratio > 1.1) {
2304 should_print = true;
2305 print_indent(level + 1);
2306 gclog_or_tty->print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
2307 }
2309 if (other_times_ms->sum() < -0.01) {
2310 print_indent(level + 1);
2311 gclog_or_tty->print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
2312 }
2314 if (other_times_ms->avg() < -0.01) {
2315 print_indent(level + 1);
2316 gclog_or_tty->print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
2317 }
2319 if (calc_other_times_ms->sum() < -0.01) {
2320 should_print = true;
2321 print_indent(level + 1);
2322 gclog_or_tty->print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
2323 }
2325 if (calc_other_times_ms->avg() < -0.01) {
2326 should_print = true;
2327 print_indent(level + 1);
2328 gclog_or_tty->print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
2329 }
2331 if (should_print)
2332 print_summary(level, "Other(Calc)", calc_other_times_ms);
2333 }
2335 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
2336 bool parallel = ParallelGCThreads > 0;
2337 MainBodySummary* body_summary = summary->main_body_summary();
2338 if (summary->get_total_seq()->num() > 0) {
2339 print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
2340 if (body_summary != NULL) {
2341 print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
2342 if (parallel) {
2343 print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
2344 print_summary(2, "Update RS", body_summary->get_update_rs_seq());
2345 print_summary(2, "Ext Root Scanning",
2346 body_summary->get_ext_root_scan_seq());
2347 print_summary(2, "Mark Stack Scanning",
2348 body_summary->get_mark_stack_scan_seq());
2349 print_summary(2, "Scan-Only Scanning",
2350 body_summary->get_scan_only_seq());
2351 print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
2352 print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
2353 print_summary(2, "Termination", body_summary->get_termination_seq());
2354 print_summary(2, "Other", body_summary->get_parallel_other_seq());
2355 {
2356 NumberSeq* other_parts[] = {
2357 body_summary->get_update_rs_seq(),
2358 body_summary->get_ext_root_scan_seq(),
2359 body_summary->get_mark_stack_scan_seq(),
2360 body_summary->get_scan_only_seq(),
2361 body_summary->get_scan_rs_seq(),
2362 body_summary->get_obj_copy_seq(),
2363 body_summary->get_termination_seq()
2364 };
2365 NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
2366 7, other_parts);
2367 check_other_times(2, body_summary->get_parallel_other_seq(),
2368 &calc_other_times_ms);
2369 }
2370 print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
2371 print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
2372 } else {
2373 print_summary(1, "Update RS", body_summary->get_update_rs_seq());
2374 print_summary(1, "Ext Root Scanning",
2375 body_summary->get_ext_root_scan_seq());
2376 print_summary(1, "Mark Stack Scanning",
2377 body_summary->get_mark_stack_scan_seq());
2378 print_summary(1, "Scan-Only Scanning",
2379 body_summary->get_scan_only_seq());
2380 print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
2381 print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
2382 }
2383 }
2384 print_summary(1, "Other", summary->get_other_seq());
2385 {
2386 NumberSeq calc_other_times_ms;
2387 if (body_summary != NULL) {
2388 // not abandoned
2389 if (parallel) {
2390 // parallel
2391 NumberSeq* other_parts[] = {
2392 body_summary->get_satb_drain_seq(),
2393 body_summary->get_parallel_seq(),
2394 body_summary->get_clear_ct_seq()
2395 };
2396 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2397 3, other_parts);
2398 } else {
2399 // serial
2400 NumberSeq* other_parts[] = {
2401 body_summary->get_satb_drain_seq(),
2402 body_summary->get_update_rs_seq(),
2403 body_summary->get_ext_root_scan_seq(),
2404 body_summary->get_mark_stack_scan_seq(),
2405 body_summary->get_scan_only_seq(),
2406 body_summary->get_scan_rs_seq(),
2407 body_summary->get_obj_copy_seq()
2408 };
2409 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2410 7, other_parts);
2411 }
2412 } else {
2413 // abandoned
2414 calc_other_times_ms = NumberSeq();
2415 }
2416 check_other_times(1, summary->get_other_seq(), &calc_other_times_ms);
2417 }
2418 } else {
2419 print_indent(0);
2420 gclog_or_tty->print_cr("none");
2421 }
2422 gclog_or_tty->print_cr("");
2423 }
2425 void
2426 G1CollectorPolicy::print_abandoned_summary(PauseSummary* summary) const {
2427 bool printed = false;
2428 if (summary->get_total_seq()->num() > 0) {
2429 printed = true;
2430 print_summary(summary);
2431 }
2432 if (!printed) {
2433 print_indent(0);
2434 gclog_or_tty->print_cr("none");
2435 gclog_or_tty->print_cr("");
2436 }
2437 }
2439 void G1CollectorPolicy::print_tracing_info() const {
2440 if (TraceGen0Time) {
2441 gclog_or_tty->print_cr("ALL PAUSES");
2442 print_summary_sd(0, "Total", _all_pause_times_ms);
2443 gclog_or_tty->print_cr("");
2444 gclog_or_tty->print_cr("");
2445 gclog_or_tty->print_cr(" Full Young GC Pauses: %8d", _full_young_pause_num);
2446 gclog_or_tty->print_cr(" Partial Young GC Pauses: %8d", _partial_young_pause_num);
2447 gclog_or_tty->print_cr("");
2449 gclog_or_tty->print_cr("EVACUATION PAUSES");
2450 print_summary(_summary);
2452 gclog_or_tty->print_cr("ABANDONED PAUSES");
2453 print_abandoned_summary(_abandoned_summary);
2455 gclog_or_tty->print_cr("MISC");
2456 print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
2457 print_summary_sd(0, "Yields", _all_yield_times_ms);
2458 for (int i = 0; i < _aux_num; ++i) {
2459 if (_all_aux_times_ms[i].num() > 0) {
2460 char buffer[96];
2461 sprintf(buffer, "Aux%d", i);
2462 print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
2463 }
2464 }
2466 size_t all_region_num = _region_num_young + _region_num_tenured;
2467 gclog_or_tty->print_cr(" New Regions %8d, Young %8d (%6.2lf%%), "
2468 "Tenured %8d (%6.2lf%%)",
2469 all_region_num,
2470 _region_num_young,
2471 (double) _region_num_young / (double) all_region_num * 100.0,
2472 _region_num_tenured,
2473 (double) _region_num_tenured / (double) all_region_num * 100.0);
2474 }
2475 if (TraceGen1Time) {
2476 if (_all_full_gc_times_ms->num() > 0) {
2477 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2478 _all_full_gc_times_ms->num(),
2479 _all_full_gc_times_ms->sum() / 1000.0);
2480 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
2481 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2482 _all_full_gc_times_ms->sd(),
2483 _all_full_gc_times_ms->maximum());
2484 }
2485 }
2486 }
2488 void G1CollectorPolicy::print_yg_surv_rate_info() const {
2489 #ifndef PRODUCT
2490 _short_lived_surv_rate_group->print_surv_rate_summary();
2491 // add this call for any other surv rate groups
2492 #endif // PRODUCT
2493 }
2495 bool
2496 G1CollectorPolicy::should_add_next_region_to_young_list() {
2497 assert(in_young_gc_mode(), "should be in young GC mode");
2498 bool ret;
2499 size_t young_list_length = _g1->young_list_length();
2500 size_t young_list_max_length = _young_list_target_length;
2501 if (G1FixedEdenSize) {
2502 young_list_max_length -= _max_survivor_regions;
2503 }
2504 if (young_list_length < young_list_max_length) {
2505 ret = true;
2506 ++_region_num_young;
2507 } else {
2508 ret = false;
2509 ++_region_num_tenured;
2510 }
2512 return ret;
2513 }
2515 #ifndef PRODUCT
2516 // for debugging, bit of a hack...
2517 static char*
2518 region_num_to_mbs(int length) {
2519 static char buffer[64];
2520 double bytes = (double) (length * HeapRegion::GrainBytes);
2521 double mbs = bytes / (double) (1024 * 1024);
2522 sprintf(buffer, "%7.2lfMB", mbs);
2523 return buffer;
2524 }
2525 #endif // PRODUCT
2527 size_t G1CollectorPolicy::max_regions(int purpose) {
2528 switch (purpose) {
2529 case GCAllocForSurvived:
2530 return _max_survivor_regions;
2531 case GCAllocForTenured:
2532 return REGIONS_UNLIMITED;
2533 default:
2534 ShouldNotReachHere();
2535 return REGIONS_UNLIMITED;
2536 };
2537 }
2539 // Calculates survivor space parameters.
2540 void G1CollectorPolicy::calculate_survivors_policy()
2541 {
2542 if (!G1UseSurvivorSpaces) {
2543 return;
2544 }
2545 if (G1FixedSurvivorSpaceSize == 0) {
2546 _max_survivor_regions = _young_list_target_length / SurvivorRatio;
2547 } else {
2548 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
2549 }
2551 if (G1FixedTenuringThreshold) {
2552 _tenuring_threshold = MaxTenuringThreshold;
2553 } else {
2554 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
2555 HeapRegion::GrainWords * _max_survivor_regions);
2556 }
2557 }
2559 bool
2560 G1CollectorPolicy_BestRegionsFirst::should_do_collection_pause(size_t
2561 word_size) {
2562 assert(_g1->regions_accounted_for(), "Region leakage!");
2563 // Initiate a pause when we reach the steady-state "used" target.
2564 size_t used_hard = (_g1->capacity() / 100) * G1SteadyStateUsed;
2565 size_t used_soft =
2566 MAX2((_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta),
2567 used_hard/2);
2568 size_t used = _g1->used();
2570 double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
2572 size_t young_list_length = _g1->young_list_length();
2573 size_t young_list_max_length = _young_list_target_length;
2574 if (G1FixedEdenSize) {
2575 young_list_max_length -= _max_survivor_regions;
2576 }
2577 bool reached_target_length = young_list_length >= young_list_max_length;
2579 if (in_young_gc_mode()) {
2580 if (reached_target_length) {
2581 assert( young_list_length > 0 && _g1->young_list_length() > 0,
2582 "invariant" );
2583 _target_pause_time_ms = max_pause_time_ms;
2584 return true;
2585 }
2586 } else {
2587 guarantee( false, "should not reach here" );
2588 }
2590 return false;
2591 }
2593 #ifndef PRODUCT
2594 class HRSortIndexIsOKClosure: public HeapRegionClosure {
2595 CollectionSetChooser* _chooser;
2596 public:
2597 HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
2598 _chooser(chooser) {}
2600 bool doHeapRegion(HeapRegion* r) {
2601 if (!r->continuesHumongous()) {
2602 assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
2603 }
2604 return false;
2605 }
2606 };
2608 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
2609 HRSortIndexIsOKClosure cl(_collectionSetChooser);
2610 _g1->heap_region_iterate(&cl);
2611 return true;
2612 }
2613 #endif
2615 void
2616 G1CollectorPolicy_BestRegionsFirst::
2617 record_collection_pause_start(double start_time_sec, size_t start_used) {
2618 G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
2619 }
2621 class NextNonCSElemFinder: public HeapRegionClosure {
2622 HeapRegion* _res;
2623 public:
2624 NextNonCSElemFinder(): _res(NULL) {}
2625 bool doHeapRegion(HeapRegion* r) {
2626 if (!r->in_collection_set()) {
2627 _res = r;
2628 return true;
2629 } else {
2630 return false;
2631 }
2632 }
2633 HeapRegion* res() { return _res; }
2634 };
2636 class KnownGarbageClosure: public HeapRegionClosure {
2637 CollectionSetChooser* _hrSorted;
2639 public:
2640 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
2641 _hrSorted(hrSorted)
2642 {}
2644 bool doHeapRegion(HeapRegion* r) {
2645 // We only include humongous regions in collection
2646 // sets when concurrent mark shows that their contained object is
2647 // unreachable.
2649 // Do we have any marking information for this region?
2650 if (r->is_marked()) {
2651 // We don't include humongous regions in collection
2652 // sets because we collect them immediately at the end of a marking
2653 // cycle. We also don't include young regions because we *must*
2654 // include them in the next collection pause.
2655 if (!r->isHumongous() && !r->is_young()) {
2656 _hrSorted->addMarkedHeapRegion(r);
2657 }
2658 }
2659 return false;
2660 }
2661 };
2663 class ParKnownGarbageHRClosure: public HeapRegionClosure {
2664 CollectionSetChooser* _hrSorted;
2665 jint _marked_regions_added;
2666 jint _chunk_size;
2667 jint _cur_chunk_idx;
2668 jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
2669 int _worker;
2670 int _invokes;
2672 void get_new_chunk() {
2673 _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
2674 _cur_chunk_end = _cur_chunk_idx + _chunk_size;
2675 }
2676 void add_region(HeapRegion* r) {
2677 if (_cur_chunk_idx == _cur_chunk_end) {
2678 get_new_chunk();
2679 }
2680 assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
2681 _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
2682 _marked_regions_added++;
2683 _cur_chunk_idx++;
2684 }
2686 public:
2687 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
2688 jint chunk_size,
2689 int worker) :
2690 _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
2691 _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
2692 _invokes(0)
2693 {}
2695 bool doHeapRegion(HeapRegion* r) {
2696 // We only include humongous regions in collection
2697 // sets when concurrent mark shows that their contained object is
2698 // unreachable.
2699 _invokes++;
2701 // Do we have any marking information for this region?
2702 if (r->is_marked()) {
2703 // We don't include humongous regions in collection
2704 // sets because we collect them immediately at the end of a marking
2705 // cycle.
2706 // We also do not include young regions in collection sets
2707 if (!r->isHumongous() && !r->is_young()) {
2708 add_region(r);
2709 }
2710 }
2711 return false;
2712 }
2713 jint marked_regions_added() { return _marked_regions_added; }
2714 int invokes() { return _invokes; }
2715 };
2717 class ParKnownGarbageTask: public AbstractGangTask {
2718 CollectionSetChooser* _hrSorted;
2719 jint _chunk_size;
2720 G1CollectedHeap* _g1;
2721 public:
2722 ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
2723 AbstractGangTask("ParKnownGarbageTask"),
2724 _hrSorted(hrSorted), _chunk_size(chunk_size),
2725 _g1(G1CollectedHeap::heap())
2726 {}
2728 void work(int i) {
2729 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
2730 // Back to zero for the claim value.
2731 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
2732 HeapRegion::InitialClaimValue);
2733 jint regions_added = parKnownGarbageCl.marked_regions_added();
2734 _hrSorted->incNumMarkedHeapRegions(regions_added);
2735 if (G1PrintParCleanupStats) {
2736 gclog_or_tty->print(" Thread %d called %d times, added %d regions to list.\n",
2737 i, parKnownGarbageCl.invokes(), regions_added);
2738 }
2739 }
2740 };
2742 void
2743 G1CollectorPolicy_BestRegionsFirst::
2744 record_concurrent_mark_cleanup_end(size_t freed_bytes,
2745 size_t max_live_bytes) {
2746 double start;
2747 if (G1PrintParCleanupStats) start = os::elapsedTime();
2748 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
2750 _collectionSetChooser->clearMarkedHeapRegions();
2751 double clear_marked_end;
2752 if (G1PrintParCleanupStats) {
2753 clear_marked_end = os::elapsedTime();
2754 gclog_or_tty->print_cr(" clear marked regions + work1: %8.3f ms.",
2755 (clear_marked_end - start)*1000.0);
2756 }
2757 if (ParallelGCThreads > 0) {
2758 const size_t OverpartitionFactor = 4;
2759 const size_t MinChunkSize = 8;
2760 const size_t ChunkSize =
2761 MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
2762 MinChunkSize);
2763 _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
2764 ChunkSize);
2765 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
2766 (int) ChunkSize);
2767 _g1->workers()->run_task(&parKnownGarbageTask);
2769 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
2770 "sanity check");
2771 } else {
2772 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
2773 _g1->heap_region_iterate(&knownGarbagecl);
2774 }
2775 double known_garbage_end;
2776 if (G1PrintParCleanupStats) {
2777 known_garbage_end = os::elapsedTime();
2778 gclog_or_tty->print_cr(" compute known garbage: %8.3f ms.",
2779 (known_garbage_end - clear_marked_end)*1000.0);
2780 }
2781 _collectionSetChooser->sortMarkedHeapRegions();
2782 double sort_end;
2783 if (G1PrintParCleanupStats) {
2784 sort_end = os::elapsedTime();
2785 gclog_or_tty->print_cr(" sorting: %8.3f ms.",
2786 (sort_end - known_garbage_end)*1000.0);
2787 }
2789 record_concurrent_mark_cleanup_end_work2();
2790 double work2_end;
2791 if (G1PrintParCleanupStats) {
2792 work2_end = os::elapsedTime();
2793 gclog_or_tty->print_cr(" work2: %8.3f ms.",
2794 (work2_end - sort_end)*1000.0);
2795 }
2796 }
2798 // Add the heap region to the collection set and return the conservative
2799 // estimate of the number of live bytes.
2800 void G1CollectorPolicy::
2801 add_to_collection_set(HeapRegion* hr) {
2802 if (G1PrintRegions) {
2803 gclog_or_tty->print_cr("added region to cset %d:["PTR_FORMAT", "PTR_FORMAT"], "
2804 "top "PTR_FORMAT", young %s",
2805 hr->hrs_index(), hr->bottom(), hr->end(),
2806 hr->top(), (hr->is_young()) ? "YES" : "NO");
2807 }
2809 if (_g1->mark_in_progress())
2810 _g1->concurrent_mark()->registerCSetRegion(hr);
2812 assert(!hr->in_collection_set(),
2813 "should not already be in the CSet");
2814 hr->set_in_collection_set(true);
2815 hr->set_next_in_collection_set(_collection_set);
2816 _collection_set = hr;
2817 _collection_set_size++;
2818 _collection_set_bytes_used_before += hr->used();
2819 _g1->register_region_with_in_cset_fast_test(hr);
2820 }
2822 void
2823 G1CollectorPolicy_BestRegionsFirst::
2824 choose_collection_set() {
2825 double non_young_start_time_sec;
2826 start_recording_regions();
2828 guarantee(_target_pause_time_ms > -1.0,
2829 "_target_pause_time_ms should have been set!");
2830 assert(_collection_set == NULL, "Precondition");
2832 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2833 double predicted_pause_time_ms = base_time_ms;
2835 double target_time_ms = _target_pause_time_ms;
2836 double time_remaining_ms = target_time_ms - base_time_ms;
2838 // the 10% and 50% values are arbitrary...
2839 if (time_remaining_ms < 0.10*target_time_ms) {
2840 time_remaining_ms = 0.50 * target_time_ms;
2841 _within_target = false;
2842 } else {
2843 _within_target = true;
2844 }
2846 // We figure out the number of bytes available for future to-space.
2847 // For new regions without marking information, we must assume the
2848 // worst-case of complete survival. If we have marking information for a
2849 // region, we can bound the amount of live data. We can add a number of
2850 // such regions, as long as the sum of the live data bounds does not
2851 // exceed the available evacuation space.
2852 size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes;
2854 size_t expansion_bytes =
2855 _g1->expansion_regions() * HeapRegion::GrainBytes;
2857 _collection_set_bytes_used_before = 0;
2858 _collection_set_size = 0;
2860 // Adjust for expansion and slop.
2861 max_live_bytes = max_live_bytes + expansion_bytes;
2863 assert(_g1->regions_accounted_for(), "Region leakage!");
2865 HeapRegion* hr;
2866 if (in_young_gc_mode()) {
2867 double young_start_time_sec = os::elapsedTime();
2869 if (G1PolicyVerbose > 0) {
2870 gclog_or_tty->print_cr("Adding %d young regions to the CSet",
2871 _g1->young_list_length());
2872 }
2873 _young_cset_length = 0;
2874 _last_young_gc_full = full_young_gcs() ? true : false;
2875 if (_last_young_gc_full)
2876 ++_full_young_pause_num;
2877 else
2878 ++_partial_young_pause_num;
2879 hr = _g1->pop_region_from_young_list();
2880 while (hr != NULL) {
2882 assert( hr->young_index_in_cset() == -1, "invariant" );
2883 assert( hr->age_in_surv_rate_group() != -1, "invariant" );
2884 hr->set_young_index_in_cset((int) _young_cset_length);
2886 ++_young_cset_length;
2887 double predicted_time_ms = predict_region_elapsed_time_ms(hr, true);
2888 time_remaining_ms -= predicted_time_ms;
2889 predicted_pause_time_ms += predicted_time_ms;
2890 assert(!hr->in_collection_set(), "invariant");
2891 add_to_collection_set(hr);
2892 record_cset_region(hr, true);
2893 max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
2894 if (G1PolicyVerbose > 0) {
2895 gclog_or_tty->print_cr(" Added [" PTR_FORMAT ", " PTR_FORMAT") to CS.",
2896 hr->bottom(), hr->end());
2897 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2898 max_live_bytes/K);
2899 }
2900 hr = _g1->pop_region_from_young_list();
2901 }
2903 record_scan_only_regions(_g1->young_list_scan_only_length());
2905 double young_end_time_sec = os::elapsedTime();
2906 _recorded_young_cset_choice_time_ms =
2907 (young_end_time_sec - young_start_time_sec) * 1000.0;
2909 non_young_start_time_sec = os::elapsedTime();
2911 if (_young_cset_length > 0 && _last_young_gc_full) {
2912 // don't bother adding more regions...
2913 goto choose_collection_set_end;
2914 }
2915 }
2917 if (!in_young_gc_mode() || !full_young_gcs()) {
2918 bool should_continue = true;
2919 NumberSeq seq;
2920 double avg_prediction = 100000000000000000.0; // something very large
2921 do {
2922 hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
2923 avg_prediction);
2924 if (hr != NULL) {
2925 double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
2926 time_remaining_ms -= predicted_time_ms;
2927 predicted_pause_time_ms += predicted_time_ms;
2928 add_to_collection_set(hr);
2929 record_cset_region(hr, false);
2930 max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
2931 if (G1PolicyVerbose > 0) {
2932 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2933 max_live_bytes/K);
2934 }
2935 seq.add(predicted_time_ms);
2936 avg_prediction = seq.avg() + seq.sd();
2937 }
2938 should_continue =
2939 ( hr != NULL) &&
2940 ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0
2941 : _collection_set_size < _young_list_fixed_length );
2942 } while (should_continue);
2944 if (!adaptive_young_list_length() &&
2945 _collection_set_size < _young_list_fixed_length)
2946 _should_revert_to_full_young_gcs = true;
2947 }
2949 choose_collection_set_end:
2950 count_CS_bytes_used();
2952 end_recording_regions();
2954 double non_young_end_time_sec = os::elapsedTime();
2955 _recorded_non_young_cset_choice_time_ms =
2956 (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
2957 }
2959 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
2960 G1CollectorPolicy::record_full_collection_end();
2961 _collectionSetChooser->updateAfterFullCollection();
2962 }
2964 void G1CollectorPolicy_BestRegionsFirst::
2965 expand_if_possible(size_t numRegions) {
2966 size_t expansion_bytes = numRegions * HeapRegion::GrainBytes;
2967 _g1->expand(expansion_bytes);
2968 }
2970 void G1CollectorPolicy_BestRegionsFirst::
2971 record_collection_pause_end(bool abandoned) {
2972 G1CollectorPolicy::record_collection_pause_end(abandoned);
2973 assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
2974 }
2976 // Local Variables: ***
2977 // c-indentation-style: gnu ***
2978 // End: ***