Wed, 25 Mar 2009 13:10:54 -0700
6543938: G1: remove the concept of popularity
Reviewed-by: iveresov, tonyp
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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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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 _cur_clear_ct_time_ms(0.0),
99 _region_num_young(0),
100 _region_num_tenured(0),
101 _prev_region_num_young(0),
102 _prev_region_num_tenured(0),
104 _aux_num(10),
105 _all_aux_times_ms(new NumberSeq[_aux_num]),
106 _cur_aux_start_times_ms(new double[_aux_num]),
107 _cur_aux_times_ms(new double[_aux_num]),
108 _cur_aux_times_set(new bool[_aux_num]),
110 _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
111 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
112 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
114 // <NEW PREDICTION>
116 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
117 _prev_collection_pause_end_ms(0.0),
118 _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
119 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
120 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
121 _cost_per_scan_only_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
122 _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
123 _partially_young_cards_per_entry_ratio_seq(
124 new TruncatedSeq(TruncatedSeqLength)),
125 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
126 _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
127 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
128 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
129 _cost_per_scan_only_region_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
130 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
131 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
132 _non_young_other_cost_per_region_ms_seq(
133 new TruncatedSeq(TruncatedSeqLength)),
135 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
136 _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
137 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
139 _pause_time_target_ms((double) G1MaxPauseTimeMS),
141 // </NEW PREDICTION>
143 _in_young_gc_mode(false),
144 _full_young_gcs(true),
145 _full_young_pause_num(0),
146 _partial_young_pause_num(0),
148 _during_marking(false),
149 _in_marking_window(false),
150 _in_marking_window_im(false),
152 _known_garbage_ratio(0.0),
153 _known_garbage_bytes(0),
155 _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
156 _target_pause_time_ms(-1.0),
158 _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
160 _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
161 _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
163 _recent_avg_pause_time_ratio(0.0),
164 _num_markings(0),
165 _n_marks(0),
166 _n_pauses_at_mark_end(0),
168 _all_full_gc_times_ms(new NumberSeq()),
170 _conc_refine_enabled(0),
171 _conc_refine_zero_traversals(0),
172 _conc_refine_max_traversals(0),
173 _conc_refine_current_delta(G1ConcRefineInitialDelta),
175 // G1PausesBtwnConcMark defaults to -1
176 // so the hack is to do the cast QQQ FIXME
177 _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
178 _n_marks_since_last_pause(0),
179 _conc_mark_initiated(false),
180 _should_initiate_conc_mark(false),
181 _should_revert_to_full_young_gcs(false),
182 _last_full_young_gc(false),
184 _prev_collection_pause_used_at_end_bytes(0),
186 _collection_set(NULL),
187 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
188 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
189 #endif // _MSC_VER
191 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
192 G1YoungSurvRateNumRegionsSummary)),
193 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
194 G1YoungSurvRateNumRegionsSummary)),
195 // add here any more surv rate groups
196 _recorded_survivor_regions(0),
197 _recorded_survivor_head(NULL),
198 _recorded_survivor_tail(NULL),
199 _survivors_age_table(true)
201 {
202 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
203 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
205 _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
206 _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
207 _par_last_scan_only_times_ms = new double[_parallel_gc_threads];
208 _par_last_scan_only_regions_scanned = new double[_parallel_gc_threads];
210 _par_last_update_rs_start_times_ms = new double[_parallel_gc_threads];
211 _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
212 _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
214 _par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads];
215 _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
216 _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads];
218 _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
220 _par_last_termination_times_ms = new double[_parallel_gc_threads];
222 // start conservatively
223 _expensive_region_limit_ms = 0.5 * (double) G1MaxPauseTimeMS;
225 // <NEW PREDICTION>
227 int index;
228 if (ParallelGCThreads == 0)
229 index = 0;
230 else if (ParallelGCThreads > 8)
231 index = 7;
232 else
233 index = ParallelGCThreads - 1;
235 _pending_card_diff_seq->add(0.0);
236 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
237 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
238 _cost_per_scan_only_region_ms_seq->add(
239 cost_per_scan_only_region_ms_defaults[index]);
240 _fully_young_cards_per_entry_ratio_seq->add(
241 fully_young_cards_per_entry_ratio_defaults[index]);
242 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
243 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
244 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
245 _young_other_cost_per_region_ms_seq->add(
246 young_other_cost_per_region_ms_defaults[index]);
247 _non_young_other_cost_per_region_ms_seq->add(
248 non_young_other_cost_per_region_ms_defaults[index]);
250 // </NEW PREDICTION>
252 double time_slice = (double) G1TimeSliceMS / 1000.0;
253 double max_gc_time = (double) G1MaxPauseTimeMS / 1000.0;
254 guarantee(max_gc_time < time_slice,
255 "Max GC time should not be greater than the time slice");
256 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
257 _sigma = (double) G1ConfidencePerc / 100.0;
259 // start conservatively (around 50ms is about right)
260 _concurrent_mark_init_times_ms->add(0.05);
261 _concurrent_mark_remark_times_ms->add(0.05);
262 _concurrent_mark_cleanup_times_ms->add(0.20);
263 _tenuring_threshold = MaxTenuringThreshold;
265 if (G1UseSurvivorSpace) {
266 // if G1FixedSurvivorSpaceSize is 0 which means the size is not
267 // fixed, then _max_survivor_regions will be calculated at
268 // calculate_young_list_target_config during initialization
269 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
270 } else {
271 _max_survivor_regions = 0;
272 }
274 initialize_all();
275 }
277 // Increment "i", mod "len"
278 static void inc_mod(int& i, int len) {
279 i++; if (i == len) i = 0;
280 }
282 void G1CollectorPolicy::initialize_flags() {
283 set_min_alignment(HeapRegion::GrainBytes);
284 set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
285 if (SurvivorRatio < 1) {
286 vm_exit_during_initialization("Invalid survivor ratio specified");
287 }
288 CollectorPolicy::initialize_flags();
289 }
291 void G1CollectorPolicy::init() {
292 // Set aside an initial future to_space.
293 _g1 = G1CollectedHeap::heap();
294 size_t regions = Universe::heap()->capacity() / HeapRegion::GrainBytes;
296 assert(Heap_lock->owned_by_self(), "Locking discipline.");
298 if (G1SteadyStateUsed < 50) {
299 vm_exit_during_initialization("G1SteadyStateUsed must be at least 50%.");
300 }
301 if (UseConcMarkSweepGC) {
302 vm_exit_during_initialization("-XX:+UseG1GC is incompatible with "
303 "-XX:+UseConcMarkSweepGC.");
304 }
306 initialize_gc_policy_counters();
308 if (G1Gen) {
309 _in_young_gc_mode = true;
311 if (G1YoungGenSize == 0) {
312 set_adaptive_young_list_length(true);
313 _young_list_fixed_length = 0;
314 } else {
315 set_adaptive_young_list_length(false);
316 _young_list_fixed_length = (G1YoungGenSize / HeapRegion::GrainBytes);
317 }
318 _free_regions_at_end_of_collection = _g1->free_regions();
319 _scan_only_regions_at_end_of_collection = 0;
320 calculate_young_list_min_length();
321 guarantee( _young_list_min_length == 0, "invariant, not enough info" );
322 calculate_young_list_target_config();
323 } else {
324 _young_list_fixed_length = 0;
325 _in_young_gc_mode = false;
326 }
327 }
329 // Create the jstat counters for the policy.
330 void G1CollectorPolicy::initialize_gc_policy_counters()
331 {
332 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen);
333 }
335 void G1CollectorPolicy::calculate_young_list_min_length() {
336 _young_list_min_length = 0;
338 if (!adaptive_young_list_length())
339 return;
341 if (_alloc_rate_ms_seq->num() > 3) {
342 double now_sec = os::elapsedTime();
343 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
344 double alloc_rate_ms = predict_alloc_rate_ms();
345 int min_regions = (int) ceil(alloc_rate_ms * when_ms);
346 int current_region_num = (int) _g1->young_list_length();
347 _young_list_min_length = min_regions + current_region_num;
348 }
349 }
351 void G1CollectorPolicy::calculate_young_list_target_config() {
352 if (adaptive_young_list_length()) {
353 size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
354 calculate_young_list_target_config(rs_lengths);
355 } else {
356 if (full_young_gcs())
357 _young_list_target_length = _young_list_fixed_length;
358 else
359 _young_list_target_length = _young_list_fixed_length / 2;
360 _young_list_target_length = MAX2(_young_list_target_length, (size_t)1);
361 size_t so_length = calculate_optimal_so_length(_young_list_target_length);
362 guarantee( so_length < _young_list_target_length, "invariant" );
363 _young_list_so_prefix_length = so_length;
364 }
365 calculate_survivors_policy();
366 }
368 // This method calculate the optimal scan-only set for a fixed young
369 // gen size. I couldn't work out how to reuse the more elaborate one,
370 // i.e. calculate_young_list_target_config(rs_length), as the loops are
371 // fundamentally different (the other one finds a config for different
372 // S-O lengths, whereas here we need to do the opposite).
373 size_t G1CollectorPolicy::calculate_optimal_so_length(
374 size_t young_list_length) {
375 if (!G1UseScanOnlyPrefix)
376 return 0;
378 if (_all_pause_times_ms->num() < 3) {
379 // we won't use a scan-only set at the beginning to allow the rest
380 // of the predictors to warm up
381 return 0;
382 }
384 if (_cost_per_scan_only_region_ms_seq->num() < 3) {
385 // then, we'll only set the S-O set to 1 for a little bit of time,
386 // to get enough information on the scanning cost
387 return 1;
388 }
390 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
391 size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
392 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
393 size_t scanned_cards;
394 if (full_young_gcs())
395 scanned_cards = predict_young_card_num(adj_rs_lengths);
396 else
397 scanned_cards = predict_non_young_card_num(adj_rs_lengths);
398 double base_time_ms = predict_base_elapsed_time_ms(pending_cards,
399 scanned_cards);
401 size_t so_length = 0;
402 double max_gc_eff = 0.0;
403 for (size_t i = 0; i < young_list_length; ++i) {
404 double gc_eff = 0.0;
405 double pause_time_ms = 0.0;
406 predict_gc_eff(young_list_length, i, base_time_ms,
407 &gc_eff, &pause_time_ms);
408 if (gc_eff > max_gc_eff) {
409 max_gc_eff = gc_eff;
410 so_length = i;
411 }
412 }
414 // set it to 95% of the optimal to make sure we sample the "area"
415 // around the optimal length to get up-to-date survival rate data
416 return so_length * 950 / 1000;
417 }
419 // This is a really cool piece of code! It finds the best
420 // target configuration (young length / scan-only prefix length) so
421 // that GC efficiency is maximized and that we also meet a pause
422 // time. It's a triple nested loop. These loops are explained below
423 // from the inside-out :-)
424 //
425 // (a) The innermost loop will try to find the optimal young length
426 // for a fixed S-O length. It uses a binary search to speed up the
427 // process. We assume that, for a fixed S-O length, as we add more
428 // young regions to the CSet, the GC efficiency will only go up (I'll
429 // skip the proof). So, using a binary search to optimize this process
430 // makes perfect sense.
431 //
432 // (b) The middle loop will fix the S-O length before calling the
433 // innermost one. It will vary it between two parameters, increasing
434 // it by a given increment.
435 //
436 // (c) The outermost loop will call the middle loop three times.
437 // (1) The first time it will explore all possible S-O length values
438 // from 0 to as large as it can get, using a coarse increment (to
439 // quickly "home in" to where the optimal seems to be).
440 // (2) The second time it will explore the values around the optimal
441 // that was found by the first iteration using a fine increment.
442 // (3) Once the optimal config has been determined by the second
443 // iteration, we'll redo the calculation, but setting the S-O length
444 // to 95% of the optimal to make sure we sample the "area"
445 // around the optimal length to get up-to-date survival rate data
446 //
447 // Termination conditions for the iterations are several: the pause
448 // time is over the limit, we do not have enough to-space, etc.
450 void G1CollectorPolicy::calculate_young_list_target_config(size_t rs_lengths) {
451 guarantee( adaptive_young_list_length(), "pre-condition" );
453 double start_time_sec = os::elapsedTime();
454 size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1MinReservePerc);
455 min_reserve_perc = MIN2((size_t) 50, min_reserve_perc);
456 size_t reserve_regions =
457 (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0);
459 if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
460 // we are in fully-young mode and there are free regions in the heap
462 double survivor_regions_evac_time =
463 predict_survivor_regions_evac_time();
465 size_t min_so_length = 0;
466 size_t max_so_length = 0;
468 if (G1UseScanOnlyPrefix) {
469 if (_all_pause_times_ms->num() < 3) {
470 // we won't use a scan-only set at the beginning to allow the rest
471 // of the predictors to warm up
472 min_so_length = 0;
473 max_so_length = 0;
474 } else if (_cost_per_scan_only_region_ms_seq->num() < 3) {
475 // then, we'll only set the S-O set to 1 for a little bit of time,
476 // to get enough information on the scanning cost
477 min_so_length = 1;
478 max_so_length = 1;
479 } else if (_in_marking_window || _last_full_young_gc) {
480 // no S-O prefix during a marking phase either, as at the end
481 // of the marking phase we'll have to use a very small young
482 // length target to fill up the rest of the CSet with
483 // non-young regions and, if we have lots of scan-only regions
484 // left-over, we will not be able to add any more non-young
485 // regions.
486 min_so_length = 0;
487 max_so_length = 0;
488 } else {
489 // this is the common case; we'll never reach the maximum, we
490 // one of the end conditions will fire well before that
491 // (hopefully!)
492 min_so_length = 0;
493 max_so_length = _free_regions_at_end_of_collection - 1;
494 }
495 } else {
496 // no S-O prefix, as the switch is not set, but we still need to
497 // do one iteration to calculate the best young target that
498 // meets the pause time; this way we reuse the same code instead
499 // of replicating it
500 min_so_length = 0;
501 max_so_length = 0;
502 }
504 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
505 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
506 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
507 size_t scanned_cards;
508 if (full_young_gcs())
509 scanned_cards = predict_young_card_num(adj_rs_lengths);
510 else
511 scanned_cards = predict_non_young_card_num(adj_rs_lengths);
512 // calculate this once, so that we don't have to recalculate it in
513 // the innermost loop
514 double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards)
515 + survivor_regions_evac_time;
516 // the result
517 size_t final_young_length = 0;
518 size_t final_so_length = 0;
519 double final_gc_eff = 0.0;
520 // we'll also keep track of how many times we go into the inner loop
521 // this is for profiling reasons
522 size_t calculations = 0;
524 // this determines which of the three iterations the outer loop is in
525 typedef enum {
526 pass_type_coarse,
527 pass_type_fine,
528 pass_type_final
529 } pass_type_t;
531 // range of the outer loop's iteration
532 size_t from_so_length = min_so_length;
533 size_t to_so_length = max_so_length;
534 guarantee( from_so_length <= to_so_length, "invariant" );
536 // this will keep the S-O length that's found by the second
537 // iteration of the outer loop; we'll keep it just in case the third
538 // iteration fails to find something
539 size_t fine_so_length = 0;
541 // the increment step for the coarse (first) iteration
542 size_t so_coarse_increments = 5;
544 // the common case, we'll start with the coarse iteration
545 pass_type_t pass = pass_type_coarse;
546 size_t so_length_incr = so_coarse_increments;
548 if (from_so_length == to_so_length) {
549 // not point in doing the coarse iteration, we'll go directly into
550 // the fine one (we essentially trying to find the optimal young
551 // length for a fixed S-O length).
552 so_length_incr = 1;
553 pass = pass_type_final;
554 } else if (to_so_length - from_so_length < 3 * so_coarse_increments) {
555 // again, the range is too short so no point in foind the coarse
556 // iteration either
557 so_length_incr = 1;
558 pass = pass_type_fine;
559 }
561 bool done = false;
562 // this is the outermost loop
563 while (!done) {
564 #ifdef TRACE_CALC_YOUNG_CONFIG
565 // leave this in for debugging, just in case
566 gclog_or_tty->print_cr("searching between " SIZE_FORMAT " and " SIZE_FORMAT
567 ", incr " SIZE_FORMAT ", pass %s",
568 from_so_length, to_so_length, so_length_incr,
569 (pass == pass_type_coarse) ? "coarse" :
570 (pass == pass_type_fine) ? "fine" : "final");
571 #endif // TRACE_CALC_YOUNG_CONFIG
573 size_t so_length = from_so_length;
574 size_t init_free_regions =
575 MAX2((size_t)0,
576 _free_regions_at_end_of_collection +
577 _scan_only_regions_at_end_of_collection - reserve_regions);
579 // this determines whether a configuration was found
580 bool gc_eff_set = false;
581 // this is the middle loop
582 while (so_length <= to_so_length) {
583 // base time, which excludes region-related time; again we
584 // calculate it once to avoid recalculating it in the
585 // innermost loop
586 double base_time_with_so_ms =
587 base_time_ms + predict_scan_only_time_ms(so_length);
588 // it's already over the pause target, go around
589 if (base_time_with_so_ms > target_pause_time_ms)
590 break;
592 size_t starting_young_length = so_length+1;
594 // we make sure that the short young length that makes sense
595 // (one more than the S-O length) is feasible
596 size_t min_young_length = starting_young_length;
597 double min_gc_eff;
598 bool min_ok;
599 ++calculations;
600 min_ok = predict_gc_eff(min_young_length, so_length,
601 base_time_with_so_ms,
602 init_free_regions, target_pause_time_ms,
603 &min_gc_eff);
605 if (min_ok) {
606 // the shortest young length is indeed feasible; we'll know
607 // set up the max young length and we'll do a binary search
608 // between min_young_length and max_young_length
609 size_t max_young_length = _free_regions_at_end_of_collection - 1;
610 double max_gc_eff = 0.0;
611 bool max_ok = false;
613 // the innermost loop! (finally!)
614 while (max_young_length > min_young_length) {
615 // we'll make sure that min_young_length is always at a
616 // feasible config
617 guarantee( min_ok, "invariant" );
619 ++calculations;
620 max_ok = predict_gc_eff(max_young_length, so_length,
621 base_time_with_so_ms,
622 init_free_regions, target_pause_time_ms,
623 &max_gc_eff);
625 size_t diff = (max_young_length - min_young_length) / 2;
626 if (max_ok) {
627 min_young_length = max_young_length;
628 min_gc_eff = max_gc_eff;
629 min_ok = true;
630 }
631 max_young_length = min_young_length + diff;
632 }
634 // the innermost loop found a config
635 guarantee( min_ok, "invariant" );
636 if (min_gc_eff > final_gc_eff) {
637 // it's the best config so far, so we'll keep it
638 final_gc_eff = min_gc_eff;
639 final_young_length = min_young_length;
640 final_so_length = so_length;
641 gc_eff_set = true;
642 }
643 }
645 // incremental the fixed S-O length and go around
646 so_length += so_length_incr;
647 }
649 // this is the end of the outermost loop and we need to decide
650 // what to do during the next iteration
651 if (pass == pass_type_coarse) {
652 // we just did the coarse pass (first iteration)
654 if (!gc_eff_set)
655 // we didn't find a feasible config so we'll just bail out; of
656 // course, it might be the case that we missed it; but I'd say
657 // it's a bit unlikely
658 done = true;
659 else {
660 // We did find a feasible config with optimal GC eff during
661 // the first pass. So the second pass we'll only consider the
662 // S-O lengths around that config with a fine increment.
664 guarantee( so_length_incr == so_coarse_increments, "invariant" );
665 guarantee( final_so_length >= min_so_length, "invariant" );
667 #ifdef TRACE_CALC_YOUNG_CONFIG
668 // leave this in for debugging, just in case
669 gclog_or_tty->print_cr(" coarse pass: SO length " SIZE_FORMAT,
670 final_so_length);
671 #endif // TRACE_CALC_YOUNG_CONFIG
673 from_so_length =
674 (final_so_length - min_so_length > so_coarse_increments) ?
675 final_so_length - so_coarse_increments + 1 : min_so_length;
676 to_so_length =
677 (max_so_length - final_so_length > so_coarse_increments) ?
678 final_so_length + so_coarse_increments - 1 : max_so_length;
680 pass = pass_type_fine;
681 so_length_incr = 1;
682 }
683 } else if (pass == pass_type_fine) {
684 // we just finished the second pass
686 if (!gc_eff_set) {
687 // we didn't find a feasible config (yes, it's possible;
688 // notice that, sometimes, we go directly into the fine
689 // iteration and skip the coarse one) so we bail out
690 done = true;
691 } else {
692 // We did find a feasible config with optimal GC eff
693 guarantee( so_length_incr == 1, "invariant" );
695 if (final_so_length == 0) {
696 // The config is of an empty S-O set, so we'll just bail out
697 done = true;
698 } else {
699 // we'll go around once more, setting the S-O length to 95%
700 // of the optimal
701 size_t new_so_length = 950 * final_so_length / 1000;
703 #ifdef TRACE_CALC_YOUNG_CONFIG
704 // leave this in for debugging, just in case
705 gclog_or_tty->print_cr(" fine pass: SO length " SIZE_FORMAT
706 ", setting it to " SIZE_FORMAT,
707 final_so_length, new_so_length);
708 #endif // TRACE_CALC_YOUNG_CONFIG
710 from_so_length = new_so_length;
711 to_so_length = new_so_length;
712 fine_so_length = final_so_length;
714 pass = pass_type_final;
715 }
716 }
717 } else if (pass == pass_type_final) {
718 // we just finished the final (third) pass
720 if (!gc_eff_set)
721 // we didn't find a feasible config, so we'll just use the one
722 // we found during the second pass, which we saved
723 final_so_length = fine_so_length;
725 // and we're done!
726 done = true;
727 } else {
728 guarantee( false, "should never reach here" );
729 }
731 // we now go around the outermost loop
732 }
734 // we should have at least one region in the target young length
735 _young_list_target_length =
736 MAX2((size_t) 1, final_young_length + _recorded_survivor_regions);
737 if (final_so_length >= final_young_length)
738 // and we need to ensure that the S-O length is not greater than
739 // the target young length (this is being a bit careful)
740 final_so_length = 0;
741 _young_list_so_prefix_length = final_so_length;
742 guarantee( !_in_marking_window || !_last_full_young_gc ||
743 _young_list_so_prefix_length == 0, "invariant" );
745 // let's keep an eye of how long we spend on this calculation
746 // right now, I assume that we'll print it when we need it; we
747 // should really adde it to the breakdown of a pause
748 double end_time_sec = os::elapsedTime();
749 double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
751 #ifdef TRACE_CALC_YOUNG_CONFIG
752 // leave this in for debugging, just in case
753 gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT
754 ", SO = " SIZE_FORMAT ", "
755 "elapsed %1.2lf ms, calcs: " SIZE_FORMAT " (%s%s) "
756 SIZE_FORMAT SIZE_FORMAT,
757 target_pause_time_ms,
758 _young_list_target_length - _young_list_so_prefix_length,
759 _young_list_so_prefix_length,
760 elapsed_time_ms,
761 calculations,
762 full_young_gcs() ? "full" : "partial",
763 should_initiate_conc_mark() ? " i-m" : "",
764 _in_marking_window,
765 _in_marking_window_im);
766 #endif // TRACE_CALC_YOUNG_CONFIG
768 if (_young_list_target_length < _young_list_min_length) {
769 // bummer; this means that, if we do a pause when the optimal
770 // config dictates, we'll violate the pause spacing target (the
771 // min length was calculate based on the application's current
772 // alloc rate);
774 // so, we have to bite the bullet, and allocate the minimum
775 // number. We'll violate our target, but we just can't meet it.
777 size_t so_length = 0;
778 // a note further up explains why we do not want an S-O length
779 // during marking
780 if (!_in_marking_window && !_last_full_young_gc)
781 // but we can still try to see whether we can find an optimal
782 // S-O length
783 so_length = calculate_optimal_so_length(_young_list_min_length);
785 #ifdef TRACE_CALC_YOUNG_CONFIG
786 // leave this in for debugging, just in case
787 gclog_or_tty->print_cr("adjusted target length from "
788 SIZE_FORMAT " to " SIZE_FORMAT
789 ", SO " SIZE_FORMAT,
790 _young_list_target_length, _young_list_min_length,
791 so_length);
792 #endif // TRACE_CALC_YOUNG_CONFIG
794 _young_list_target_length =
795 MAX2(_young_list_min_length, (size_t)1);
796 _young_list_so_prefix_length = so_length;
797 }
798 } else {
799 // we are in a partially-young mode or we've run out of regions (due
800 // to evacuation failure)
802 #ifdef TRACE_CALC_YOUNG_CONFIG
803 // leave this in for debugging, just in case
804 gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
805 ", SO " SIZE_FORMAT,
806 _young_list_min_length, 0);
807 #endif // TRACE_CALC_YOUNG_CONFIG
809 // we'll do the pause as soon as possible and with no S-O prefix
810 // (see above for the reasons behind the latter)
811 _young_list_target_length =
812 MAX2(_young_list_min_length, (size_t) 1);
813 _young_list_so_prefix_length = 0;
814 }
816 _rs_lengths_prediction = rs_lengths;
817 }
819 // This is used by: calculate_optimal_so_length(length). It returns
820 // the GC eff and predicted pause time for a particular config
821 void
822 G1CollectorPolicy::predict_gc_eff(size_t young_length,
823 size_t so_length,
824 double base_time_ms,
825 double* ret_gc_eff,
826 double* ret_pause_time_ms) {
827 double so_time_ms = predict_scan_only_time_ms(so_length);
828 double accum_surv_rate_adj = 0.0;
829 if (so_length > 0)
830 accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
831 double accum_surv_rate =
832 accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
833 size_t bytes_to_copy =
834 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
835 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
836 double young_other_time_ms =
837 predict_young_other_time_ms(young_length - so_length);
838 double pause_time_ms =
839 base_time_ms + so_time_ms + copy_time_ms + young_other_time_ms;
840 size_t reclaimed_bytes =
841 (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
842 double gc_eff = (double) reclaimed_bytes / pause_time_ms;
844 *ret_gc_eff = gc_eff;
845 *ret_pause_time_ms = pause_time_ms;
846 }
848 // This is used by: calculate_young_list_target_config(rs_length). It
849 // returns the GC eff of a particular config. It returns false if that
850 // config violates any of the end conditions of the search in the
851 // calling method, or true upon success. The end conditions were put
852 // here since it's called twice and it was best not to replicate them
853 // in the caller. Also, passing the parameteres avoids having to
854 // recalculate them in the innermost loop.
855 bool
856 G1CollectorPolicy::predict_gc_eff(size_t young_length,
857 size_t so_length,
858 double base_time_with_so_ms,
859 size_t init_free_regions,
860 double target_pause_time_ms,
861 double* ret_gc_eff) {
862 *ret_gc_eff = 0.0;
864 if (young_length >= init_free_regions)
865 // end condition 1: not enough space for the young regions
866 return false;
868 double accum_surv_rate_adj = 0.0;
869 if (so_length > 0)
870 accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
871 double accum_surv_rate =
872 accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
873 size_t bytes_to_copy =
874 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
875 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
876 double young_other_time_ms =
877 predict_young_other_time_ms(young_length - so_length);
878 double pause_time_ms =
879 base_time_with_so_ms + copy_time_ms + young_other_time_ms;
881 if (pause_time_ms > target_pause_time_ms)
882 // end condition 2: over the target pause time
883 return false;
885 size_t reclaimed_bytes =
886 (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
887 size_t free_bytes =
888 (init_free_regions - young_length) * HeapRegion::GrainBytes;
890 if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes)
891 // end condition 3: out of to-space (conservatively)
892 return false;
894 // success!
895 double gc_eff = (double) reclaimed_bytes / pause_time_ms;
896 *ret_gc_eff = gc_eff;
898 return true;
899 }
901 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
902 double survivor_regions_evac_time = 0.0;
903 for (HeapRegion * r = _recorded_survivor_head;
904 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
905 r = r->get_next_young_region()) {
906 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
907 }
908 return survivor_regions_evac_time;
909 }
911 void G1CollectorPolicy::check_prediction_validity() {
912 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
914 size_t rs_lengths = _g1->young_list_sampled_rs_lengths();
915 if (rs_lengths > _rs_lengths_prediction) {
916 // add 10% to avoid having to recalculate often
917 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
918 calculate_young_list_target_config(rs_lengths_prediction);
919 }
920 }
922 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
923 bool is_tlab,
924 bool* gc_overhead_limit_was_exceeded) {
925 guarantee(false, "Not using this policy feature yet.");
926 return NULL;
927 }
929 // This method controls how a collector handles one or more
930 // of its generations being fully allocated.
931 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
932 bool is_tlab) {
933 guarantee(false, "Not using this policy feature yet.");
934 return NULL;
935 }
938 #ifndef PRODUCT
939 bool G1CollectorPolicy::verify_young_ages() {
940 HeapRegion* head = _g1->young_list_first_region();
941 return
942 verify_young_ages(head, _short_lived_surv_rate_group);
943 // also call verify_young_ages on any additional surv rate groups
944 }
946 bool
947 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
948 SurvRateGroup *surv_rate_group) {
949 guarantee( surv_rate_group != NULL, "pre-condition" );
951 const char* name = surv_rate_group->name();
952 bool ret = true;
953 int prev_age = -1;
955 for (HeapRegion* curr = head;
956 curr != NULL;
957 curr = curr->get_next_young_region()) {
958 SurvRateGroup* group = curr->surv_rate_group();
959 if (group == NULL && !curr->is_survivor()) {
960 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
961 ret = false;
962 }
964 if (surv_rate_group == group) {
965 int age = curr->age_in_surv_rate_group();
967 if (age < 0) {
968 gclog_or_tty->print_cr("## %s: encountered negative age", name);
969 ret = false;
970 }
972 if (age <= prev_age) {
973 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
974 "(%d, %d)", name, age, prev_age);
975 ret = false;
976 }
977 prev_age = age;
978 }
979 }
981 return ret;
982 }
983 #endif // PRODUCT
985 void G1CollectorPolicy::record_full_collection_start() {
986 _cur_collection_start_sec = os::elapsedTime();
987 // Release the future to-space so that it is available for compaction into.
988 _g1->set_full_collection();
989 }
991 void G1CollectorPolicy::record_full_collection_end() {
992 // Consider this like a collection pause for the purposes of allocation
993 // since last pause.
994 double end_sec = os::elapsedTime();
995 double full_gc_time_sec = end_sec - _cur_collection_start_sec;
996 double full_gc_time_ms = full_gc_time_sec * 1000.0;
998 checkpoint_conc_overhead();
1000 _all_full_gc_times_ms->add(full_gc_time_ms);
1002 update_recent_gc_times(end_sec, full_gc_time_ms);
1004 _g1->clear_full_collection();
1006 // "Nuke" the heuristics that control the fully/partially young GC
1007 // transitions and make sure we start with fully young GCs after the
1008 // Full GC.
1009 set_full_young_gcs(true);
1010 _last_full_young_gc = false;
1011 _should_revert_to_full_young_gcs = false;
1012 _should_initiate_conc_mark = false;
1013 _known_garbage_bytes = 0;
1014 _known_garbage_ratio = 0.0;
1015 _in_marking_window = false;
1016 _in_marking_window_im = false;
1018 _short_lived_surv_rate_group->record_scan_only_prefix(0);
1019 _short_lived_surv_rate_group->start_adding_regions();
1020 // also call this on any additional surv rate groups
1022 record_survivor_regions(0, NULL, NULL);
1024 _prev_region_num_young = _region_num_young;
1025 _prev_region_num_tenured = _region_num_tenured;
1027 _free_regions_at_end_of_collection = _g1->free_regions();
1028 _scan_only_regions_at_end_of_collection = 0;
1029 // Reset survivors SurvRateGroup.
1030 _survivor_surv_rate_group->reset();
1031 calculate_young_list_min_length();
1032 calculate_young_list_target_config();
1033 }
1035 void G1CollectorPolicy::record_before_bytes(size_t bytes) {
1036 _bytes_in_to_space_before_gc += bytes;
1037 }
1039 void G1CollectorPolicy::record_after_bytes(size_t bytes) {
1040 _bytes_in_to_space_after_gc += bytes;
1041 }
1043 void G1CollectorPolicy::record_stop_world_start() {
1044 _stop_world_start = os::elapsedTime();
1045 }
1047 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
1048 size_t start_used) {
1049 if (PrintGCDetails) {
1050 gclog_or_tty->stamp(PrintGCTimeStamps);
1051 gclog_or_tty->print("[GC pause");
1052 if (in_young_gc_mode())
1053 gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
1054 }
1056 assert(_g1->used_regions() == _g1->recalculate_used_regions(),
1057 "sanity");
1058 assert(_g1->used() == _g1->recalculate_used(), "sanity");
1060 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
1061 _all_stop_world_times_ms->add(s_w_t_ms);
1062 _stop_world_start = 0.0;
1064 _cur_collection_start_sec = start_time_sec;
1065 _cur_collection_pause_used_at_start_bytes = start_used;
1066 _cur_collection_pause_used_regions_at_start = _g1->used_regions();
1067 _pending_cards = _g1->pending_card_num();
1068 _max_pending_cards = _g1->max_pending_card_num();
1070 _bytes_in_to_space_before_gc = 0;
1071 _bytes_in_to_space_after_gc = 0;
1072 _bytes_in_collection_set_before_gc = 0;
1074 #ifdef DEBUG
1075 // initialise these to something well known so that we can spot
1076 // if they are not set properly
1078 for (int i = 0; i < _parallel_gc_threads; ++i) {
1079 _par_last_ext_root_scan_times_ms[i] = -666.0;
1080 _par_last_mark_stack_scan_times_ms[i] = -666.0;
1081 _par_last_scan_only_times_ms[i] = -666.0;
1082 _par_last_scan_only_regions_scanned[i] = -666.0;
1083 _par_last_update_rs_start_times_ms[i] = -666.0;
1084 _par_last_update_rs_times_ms[i] = -666.0;
1085 _par_last_update_rs_processed_buffers[i] = -666.0;
1086 _par_last_scan_rs_start_times_ms[i] = -666.0;
1087 _par_last_scan_rs_times_ms[i] = -666.0;
1088 _par_last_scan_new_refs_times_ms[i] = -666.0;
1089 _par_last_obj_copy_times_ms[i] = -666.0;
1090 _par_last_termination_times_ms[i] = -666.0;
1091 }
1092 #endif
1094 for (int i = 0; i < _aux_num; ++i) {
1095 _cur_aux_times_ms[i] = 0.0;
1096 _cur_aux_times_set[i] = false;
1097 }
1099 _satb_drain_time_set = false;
1100 _last_satb_drain_processed_buffers = -1;
1102 if (in_young_gc_mode())
1103 _last_young_gc_full = false;
1106 // do that for any other surv rate groups
1107 _short_lived_surv_rate_group->stop_adding_regions();
1108 size_t short_lived_so_length = _young_list_so_prefix_length;
1109 _short_lived_surv_rate_group->record_scan_only_prefix(short_lived_so_length);
1110 tag_scan_only(short_lived_so_length);
1112 if (G1UseSurvivorSpace) {
1113 _survivors_age_table.clear();
1114 }
1116 assert( verify_young_ages(), "region age verification" );
1117 }
1119 void G1CollectorPolicy::tag_scan_only(size_t short_lived_scan_only_length) {
1120 // done in a way that it can be extended for other surv rate groups too...
1122 HeapRegion* head = _g1->young_list_first_region();
1123 bool finished_short_lived = (short_lived_scan_only_length == 0);
1125 if (finished_short_lived)
1126 return;
1128 for (HeapRegion* curr = head;
1129 curr != NULL;
1130 curr = curr->get_next_young_region()) {
1131 SurvRateGroup* surv_rate_group = curr->surv_rate_group();
1132 int age = curr->age_in_surv_rate_group();
1134 if (surv_rate_group == _short_lived_surv_rate_group) {
1135 if ((size_t)age < short_lived_scan_only_length)
1136 curr->set_scan_only();
1137 else
1138 finished_short_lived = true;
1139 }
1142 if (finished_short_lived)
1143 return;
1144 }
1146 guarantee( false, "we should never reach here" );
1147 }
1149 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
1150 _mark_closure_time_ms = mark_closure_time_ms;
1151 }
1153 void G1CollectorPolicy::record_concurrent_mark_init_start() {
1154 _mark_init_start_sec = os::elapsedTime();
1155 guarantee(!in_young_gc_mode(), "should not do be here in young GC mode");
1156 }
1158 void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double
1159 mark_init_elapsed_time_ms) {
1160 _during_marking = true;
1161 _should_initiate_conc_mark = false;
1162 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
1163 }
1165 void G1CollectorPolicy::record_concurrent_mark_init_end() {
1166 double end_time_sec = os::elapsedTime();
1167 double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
1168 _concurrent_mark_init_times_ms->add(elapsed_time_ms);
1169 checkpoint_conc_overhead();
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 checkpoint_conc_overhead();
1184 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
1185 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1186 _prev_collection_pause_end_ms += elapsed_time_ms;
1188 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
1189 }
1191 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
1192 _mark_cleanup_start_sec = os::elapsedTime();
1193 }
1195 void
1196 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
1197 size_t max_live_bytes) {
1198 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
1199 record_concurrent_mark_cleanup_end_work2();
1200 }
1202 void
1203 G1CollectorPolicy::
1204 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
1205 size_t max_live_bytes) {
1206 if (_n_marks < 2) _n_marks++;
1207 if (G1PolicyVerbose > 0)
1208 gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB "
1209 " (of " SIZE_FORMAT " MB heap).",
1210 max_live_bytes/M, _g1->capacity()/M);
1211 }
1213 // The important thing about this is that it includes "os::elapsedTime".
1214 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
1215 checkpoint_conc_overhead();
1216 double end_time_sec = os::elapsedTime();
1217 double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
1218 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1219 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1220 _prev_collection_pause_end_ms += elapsed_time_ms;
1222 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
1224 _num_markings++;
1226 // We did a marking, so reset the "since_last_mark" variables.
1227 double considerConcMarkCost = 1.0;
1228 // If there are available processors, concurrent activity is free...
1229 if (Threads::number_of_non_daemon_threads() * 2 <
1230 os::active_processor_count()) {
1231 considerConcMarkCost = 0.0;
1232 }
1233 _n_pauses_at_mark_end = _n_pauses;
1234 _n_marks_since_last_pause++;
1235 _conc_mark_initiated = false;
1236 }
1238 void
1239 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
1240 if (in_young_gc_mode()) {
1241 _should_revert_to_full_young_gcs = false;
1242 _last_full_young_gc = true;
1243 _in_marking_window = false;
1244 if (adaptive_young_list_length())
1245 calculate_young_list_target_config();
1246 }
1247 }
1249 void G1CollectorPolicy::record_concurrent_pause() {
1250 if (_stop_world_start > 0.0) {
1251 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
1252 _all_yield_times_ms->add(yield_ms);
1253 }
1254 }
1256 void G1CollectorPolicy::record_concurrent_pause_end() {
1257 }
1259 void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() {
1260 _cur_CH_strong_roots_end_sec = os::elapsedTime();
1261 _cur_CH_strong_roots_dur_ms =
1262 (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0;
1263 }
1265 void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() {
1266 _cur_G1_strong_roots_end_sec = os::elapsedTime();
1267 _cur_G1_strong_roots_dur_ms =
1268 (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0;
1269 }
1271 template<class T>
1272 T sum_of(T* sum_arr, int start, int n, int N) {
1273 T sum = (T)0;
1274 for (int i = 0; i < n; i++) {
1275 int j = (start + i) % N;
1276 sum += sum_arr[j];
1277 }
1278 return sum;
1279 }
1281 void G1CollectorPolicy::print_par_stats (int level,
1282 const char* str,
1283 double* data,
1284 bool summary) {
1285 double min = data[0], max = data[0];
1286 double total = 0.0;
1287 int j;
1288 for (j = 0; j < level; ++j)
1289 gclog_or_tty->print(" ");
1290 gclog_or_tty->print("[%s (ms):", str);
1291 for (uint i = 0; i < ParallelGCThreads; ++i) {
1292 double val = data[i];
1293 if (val < min)
1294 min = val;
1295 if (val > max)
1296 max = val;
1297 total += val;
1298 gclog_or_tty->print(" %3.1lf", val);
1299 }
1300 if (summary) {
1301 gclog_or_tty->print_cr("");
1302 double avg = total / (double) ParallelGCThreads;
1303 gclog_or_tty->print(" ");
1304 for (j = 0; j < level; ++j)
1305 gclog_or_tty->print(" ");
1306 gclog_or_tty->print("Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf",
1307 avg, min, max);
1308 }
1309 gclog_or_tty->print_cr("]");
1310 }
1312 void G1CollectorPolicy::print_par_buffers (int level,
1313 const char* str,
1314 double* data,
1315 bool summary) {
1316 double min = data[0], max = data[0];
1317 double total = 0.0;
1318 int j;
1319 for (j = 0; j < level; ++j)
1320 gclog_or_tty->print(" ");
1321 gclog_or_tty->print("[%s :", str);
1322 for (uint i = 0; i < ParallelGCThreads; ++i) {
1323 double val = data[i];
1324 if (val < min)
1325 min = val;
1326 if (val > max)
1327 max = val;
1328 total += val;
1329 gclog_or_tty->print(" %d", (int) val);
1330 }
1331 if (summary) {
1332 gclog_or_tty->print_cr("");
1333 double avg = total / (double) ParallelGCThreads;
1334 gclog_or_tty->print(" ");
1335 for (j = 0; j < level; ++j)
1336 gclog_or_tty->print(" ");
1337 gclog_or_tty->print("Sum: %d, Avg: %d, Min: %d, Max: %d",
1338 (int)total, (int)avg, (int)min, (int)max);
1339 }
1340 gclog_or_tty->print_cr("]");
1341 }
1343 void G1CollectorPolicy::print_stats (int level,
1344 const char* str,
1345 double value) {
1346 for (int j = 0; j < level; ++j)
1347 gclog_or_tty->print(" ");
1348 gclog_or_tty->print_cr("[%s: %5.1lf ms]", str, value);
1349 }
1351 void G1CollectorPolicy::print_stats (int level,
1352 const char* str,
1353 int value) {
1354 for (int j = 0; j < level; ++j)
1355 gclog_or_tty->print(" ");
1356 gclog_or_tty->print_cr("[%s: %d]", str, value);
1357 }
1359 double G1CollectorPolicy::avg_value (double* data) {
1360 if (ParallelGCThreads > 0) {
1361 double ret = 0.0;
1362 for (uint i = 0; i < ParallelGCThreads; ++i)
1363 ret += data[i];
1364 return ret / (double) ParallelGCThreads;
1365 } else {
1366 return data[0];
1367 }
1368 }
1370 double G1CollectorPolicy::max_value (double* data) {
1371 if (ParallelGCThreads > 0) {
1372 double ret = data[0];
1373 for (uint i = 1; i < ParallelGCThreads; ++i)
1374 if (data[i] > ret)
1375 ret = data[i];
1376 return ret;
1377 } else {
1378 return data[0];
1379 }
1380 }
1382 double G1CollectorPolicy::sum_of_values (double* data) {
1383 if (ParallelGCThreads > 0) {
1384 double sum = 0.0;
1385 for (uint i = 0; i < ParallelGCThreads; i++)
1386 sum += data[i];
1387 return sum;
1388 } else {
1389 return data[0];
1390 }
1391 }
1393 double G1CollectorPolicy::max_sum (double* data1,
1394 double* data2) {
1395 double ret = data1[0] + data2[0];
1397 if (ParallelGCThreads > 0) {
1398 for (uint i = 1; i < ParallelGCThreads; ++i) {
1399 double data = data1[i] + data2[i];
1400 if (data > ret)
1401 ret = data;
1402 }
1403 }
1404 return ret;
1405 }
1407 // Anything below that is considered to be zero
1408 #define MIN_TIMER_GRANULARITY 0.0000001
1410 void G1CollectorPolicy::record_collection_pause_end(bool abandoned) {
1411 double end_time_sec = os::elapsedTime();
1412 double elapsed_ms = _last_pause_time_ms;
1413 bool parallel = ParallelGCThreads > 0;
1414 double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0;
1415 size_t rs_size =
1416 _cur_collection_pause_used_regions_at_start - collection_set_size();
1417 size_t cur_used_bytes = _g1->used();
1418 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1419 bool last_pause_included_initial_mark = false;
1420 bool update_stats = !abandoned && !_g1->evacuation_failed();
1422 #ifndef PRODUCT
1423 if (G1YoungSurvRateVerbose) {
1424 gclog_or_tty->print_cr("");
1425 _short_lived_surv_rate_group->print();
1426 // do that for any other surv rate groups too
1427 }
1428 #endif // PRODUCT
1430 checkpoint_conc_overhead();
1432 if (in_young_gc_mode()) {
1433 last_pause_included_initial_mark = _should_initiate_conc_mark;
1434 if (last_pause_included_initial_mark)
1435 record_concurrent_mark_init_end_pre(0.0);
1437 size_t min_used_targ =
1438 (_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta);
1440 if (cur_used_bytes > min_used_targ) {
1441 if (cur_used_bytes <= _prev_collection_pause_used_at_end_bytes) {
1442 } else if (!_g1->mark_in_progress() && !_last_full_young_gc) {
1443 _should_initiate_conc_mark = true;
1444 }
1445 }
1447 _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
1448 }
1450 _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
1451 end_time_sec, false);
1453 guarantee(_cur_collection_pause_used_regions_at_start >=
1454 collection_set_size(),
1455 "Negative RS size?");
1457 // This assert is exempted when we're doing parallel collection pauses,
1458 // because the fragmentation caused by the parallel GC allocation buffers
1459 // can lead to more memory being used during collection than was used
1460 // before. Best leave this out until the fragmentation problem is fixed.
1461 // Pauses in which evacuation failed can also lead to negative
1462 // collections, since no space is reclaimed from a region containing an
1463 // object whose evacuation failed.
1464 // Further, we're now always doing parallel collection. But I'm still
1465 // leaving this here as a placeholder for a more precise assertion later.
1466 // (DLD, 10/05.)
1467 assert((true || parallel) // Always using GC LABs now.
1468 || _g1->evacuation_failed()
1469 || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
1470 "Negative collection");
1472 size_t freed_bytes =
1473 _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
1474 size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
1475 double survival_fraction =
1476 (double)surviving_bytes/
1477 (double)_collection_set_bytes_used_before;
1479 _n_pauses++;
1481 if (update_stats) {
1482 _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms);
1483 _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms);
1484 _recent_evac_times_ms->add(evac_ms);
1485 _recent_pause_times_ms->add(elapsed_ms);
1487 _recent_rs_sizes->add(rs_size);
1489 // We exempt parallel collection from this check because Alloc Buffer
1490 // fragmentation can produce negative collections. Same with evac
1491 // failure.
1492 // Further, we're now always doing parallel collection. But I'm still
1493 // leaving this here as a placeholder for a more precise assertion later.
1494 // (DLD, 10/05.
1495 assert((true || parallel)
1496 || _g1->evacuation_failed()
1497 || surviving_bytes <= _collection_set_bytes_used_before,
1498 "Or else negative collection!");
1499 _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
1500 _recent_CS_bytes_surviving->add(surviving_bytes);
1502 // this is where we update the allocation rate of the application
1503 double app_time_ms =
1504 (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
1505 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1506 // This usually happens due to the timer not having the required
1507 // granularity. Some Linuxes are the usual culprits.
1508 // We'll just set it to something (arbitrarily) small.
1509 app_time_ms = 1.0;
1510 }
1511 size_t regions_allocated =
1512 (_region_num_young - _prev_region_num_young) +
1513 (_region_num_tenured - _prev_region_num_tenured);
1514 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1515 _alloc_rate_ms_seq->add(alloc_rate_ms);
1516 _prev_region_num_young = _region_num_young;
1517 _prev_region_num_tenured = _region_num_tenured;
1519 double interval_ms =
1520 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1521 update_recent_gc_times(end_time_sec, elapsed_ms);
1522 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1523 assert(recent_avg_pause_time_ratio() < 1.00, "All GC?");
1524 }
1526 if (G1PolicyVerbose > 1) {
1527 gclog_or_tty->print_cr(" Recording collection pause(%d)", _n_pauses);
1528 }
1530 PauseSummary* summary;
1531 if (abandoned) {
1532 summary = _abandoned_summary;
1533 } else {
1534 summary = _summary;
1535 }
1537 double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
1538 double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
1539 double scan_only_time = avg_value(_par_last_scan_only_times_ms);
1540 double scan_only_regions_scanned =
1541 sum_of_values(_par_last_scan_only_regions_scanned);
1542 double update_rs_time = avg_value(_par_last_update_rs_times_ms);
1543 double update_rs_processed_buffers =
1544 sum_of_values(_par_last_update_rs_processed_buffers);
1545 double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
1546 double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
1547 double termination_time = avg_value(_par_last_termination_times_ms);
1549 double parallel_other_time = _cur_collection_par_time_ms -
1550 (update_rs_time + ext_root_scan_time + mark_stack_scan_time +
1551 scan_only_time + scan_rs_time + obj_copy_time + termination_time);
1552 if (update_stats) {
1553 MainBodySummary* body_summary = summary->main_body_summary();
1554 guarantee(body_summary != NULL, "should not be null!");
1556 if (_satb_drain_time_set)
1557 body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
1558 else
1559 body_summary->record_satb_drain_time_ms(0.0);
1560 body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
1561 body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
1562 body_summary->record_scan_only_time_ms(scan_only_time);
1563 body_summary->record_update_rs_time_ms(update_rs_time);
1564 body_summary->record_scan_rs_time_ms(scan_rs_time);
1565 body_summary->record_obj_copy_time_ms(obj_copy_time);
1566 if (parallel) {
1567 body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
1568 body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
1569 body_summary->record_termination_time_ms(termination_time);
1570 body_summary->record_parallel_other_time_ms(parallel_other_time);
1571 }
1572 body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
1573 }
1575 if (G1PolicyVerbose > 1) {
1576 gclog_or_tty->print_cr(" ET: %10.6f ms (avg: %10.6f ms)\n"
1577 " CH Strong: %10.6f ms (avg: %10.6f ms)\n"
1578 " G1 Strong: %10.6f ms (avg: %10.6f ms)\n"
1579 " Evac: %10.6f ms (avg: %10.6f ms)\n"
1580 " ET-RS: %10.6f ms (avg: %10.6f ms)\n"
1581 " |RS|: " SIZE_FORMAT,
1582 elapsed_ms, recent_avg_time_for_pauses_ms(),
1583 _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(),
1584 _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(),
1585 evac_ms, recent_avg_time_for_evac_ms(),
1586 scan_rs_time,
1587 recent_avg_time_for_pauses_ms() -
1588 recent_avg_time_for_G1_strong_ms(),
1589 rs_size);
1591 gclog_or_tty->print_cr(" Used at start: " SIZE_FORMAT"K"
1592 " At end " SIZE_FORMAT "K\n"
1593 " garbage : " SIZE_FORMAT "K"
1594 " of " SIZE_FORMAT "K\n"
1595 " survival : %6.2f%% (%6.2f%% avg)",
1596 _cur_collection_pause_used_at_start_bytes/K,
1597 _g1->used()/K, freed_bytes/K,
1598 _collection_set_bytes_used_before/K,
1599 survival_fraction*100.0,
1600 recent_avg_survival_fraction()*100.0);
1601 gclog_or_tty->print_cr(" Recent %% gc pause time: %6.2f",
1602 recent_avg_pause_time_ratio() * 100.0);
1603 }
1605 double other_time_ms = elapsed_ms;
1607 if (!abandoned) {
1608 if (_satb_drain_time_set)
1609 other_time_ms -= _cur_satb_drain_time_ms;
1611 if (parallel)
1612 other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
1613 else
1614 other_time_ms -=
1615 update_rs_time +
1616 ext_root_scan_time + mark_stack_scan_time + scan_only_time +
1617 scan_rs_time + obj_copy_time;
1618 }
1620 if (PrintGCDetails) {
1621 gclog_or_tty->print_cr("%s%s, %1.8lf secs]",
1622 abandoned ? " (abandoned)" : "",
1623 (last_pause_included_initial_mark) ? " (initial-mark)" : "",
1624 elapsed_ms / 1000.0);
1626 if (!abandoned) {
1627 if (_satb_drain_time_set) {
1628 print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
1629 }
1630 if (_last_satb_drain_processed_buffers >= 0) {
1631 print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
1632 }
1633 if (parallel) {
1634 print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
1635 print_par_stats(2, "Update RS (Start)", _par_last_update_rs_start_times_ms, false);
1636 print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
1637 if (G1RSBarrierUseQueue)
1638 print_par_buffers(3, "Processed Buffers",
1639 _par_last_update_rs_processed_buffers, true);
1640 print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
1641 print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
1642 print_par_stats(2, "Scan-Only Scanning", _par_last_scan_only_times_ms);
1643 print_par_buffers(3, "Scan-Only Regions",
1644 _par_last_scan_only_regions_scanned, true);
1645 print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
1646 print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
1647 print_par_stats(2, "Termination", _par_last_termination_times_ms);
1648 print_stats(2, "Other", parallel_other_time);
1649 print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
1650 } else {
1651 print_stats(1, "Update RS", update_rs_time);
1652 if (G1RSBarrierUseQueue)
1653 print_stats(2, "Processed Buffers",
1654 (int)update_rs_processed_buffers);
1655 print_stats(1, "Ext Root Scanning", ext_root_scan_time);
1656 print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
1657 print_stats(1, "Scan-Only Scanning", scan_only_time);
1658 print_stats(1, "Scan RS", scan_rs_time);
1659 print_stats(1, "Object Copying", obj_copy_time);
1660 }
1661 }
1662 print_stats(1, "Other", other_time_ms);
1663 for (int i = 0; i < _aux_num; ++i) {
1664 if (_cur_aux_times_set[i]) {
1665 char buffer[96];
1666 sprintf(buffer, "Aux%d", i);
1667 print_stats(1, buffer, _cur_aux_times_ms[i]);
1668 }
1669 }
1670 }
1671 if (PrintGCDetails)
1672 gclog_or_tty->print(" [");
1673 if (PrintGC || PrintGCDetails)
1674 _g1->print_size_transition(gclog_or_tty,
1675 _cur_collection_pause_used_at_start_bytes,
1676 _g1->used(), _g1->capacity());
1677 if (PrintGCDetails)
1678 gclog_or_tty->print_cr("]");
1680 _all_pause_times_ms->add(elapsed_ms);
1681 if (update_stats) {
1682 summary->record_total_time_ms(elapsed_ms);
1683 summary->record_other_time_ms(other_time_ms);
1684 }
1685 for (int i = 0; i < _aux_num; ++i)
1686 if (_cur_aux_times_set[i])
1687 _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
1689 // Reset marks-between-pauses counter.
1690 _n_marks_since_last_pause = 0;
1692 // Update the efficiency-since-mark vars.
1693 double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
1694 if (elapsed_ms < MIN_TIMER_GRANULARITY) {
1695 // This usually happens due to the timer not having the required
1696 // granularity. Some Linuxes are the usual culprits.
1697 // We'll just set it to something (arbitrarily) small.
1698 proc_ms = 1.0;
1699 }
1700 double cur_efficiency = (double) freed_bytes / proc_ms;
1702 bool new_in_marking_window = _in_marking_window;
1703 bool new_in_marking_window_im = false;
1704 if (_should_initiate_conc_mark) {
1705 new_in_marking_window = true;
1706 new_in_marking_window_im = true;
1707 }
1709 if (in_young_gc_mode()) {
1710 if (_last_full_young_gc) {
1711 set_full_young_gcs(false);
1712 _last_full_young_gc = false;
1713 }
1715 if ( !_last_young_gc_full ) {
1716 if ( _should_revert_to_full_young_gcs ||
1717 _known_garbage_ratio < 0.05 ||
1718 (adaptive_young_list_length() &&
1719 (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) {
1720 set_full_young_gcs(true);
1721 }
1722 }
1723 _should_revert_to_full_young_gcs = false;
1725 if (_last_young_gc_full && !_during_marking)
1726 _young_gc_eff_seq->add(cur_efficiency);
1727 }
1729 _short_lived_surv_rate_group->start_adding_regions();
1730 // do that for any other surv rate groupsx
1732 // <NEW PREDICTION>
1734 if (update_stats) {
1735 double pause_time_ms = elapsed_ms;
1737 size_t diff = 0;
1738 if (_max_pending_cards >= _pending_cards)
1739 diff = _max_pending_cards - _pending_cards;
1740 _pending_card_diff_seq->add((double) diff);
1742 double cost_per_card_ms = 0.0;
1743 if (_pending_cards > 0) {
1744 cost_per_card_ms = update_rs_time / (double) _pending_cards;
1745 _cost_per_card_ms_seq->add(cost_per_card_ms);
1746 }
1748 double cost_per_scan_only_region_ms = 0.0;
1749 if (scan_only_regions_scanned > 0.0) {
1750 cost_per_scan_only_region_ms =
1751 scan_only_time / scan_only_regions_scanned;
1752 if (_in_marking_window_im)
1753 _cost_per_scan_only_region_ms_during_cm_seq->add(cost_per_scan_only_region_ms);
1754 else
1755 _cost_per_scan_only_region_ms_seq->add(cost_per_scan_only_region_ms);
1756 }
1758 size_t cards_scanned = _g1->cards_scanned();
1760 double cost_per_entry_ms = 0.0;
1761 if (cards_scanned > 10) {
1762 cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
1763 if (_last_young_gc_full)
1764 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1765 else
1766 _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1767 }
1769 if (_max_rs_lengths > 0) {
1770 double cards_per_entry_ratio =
1771 (double) cards_scanned / (double) _max_rs_lengths;
1772 if (_last_young_gc_full)
1773 _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1774 else
1775 _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1776 }
1778 size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1779 if (rs_length_diff >= 0)
1780 _rs_length_diff_seq->add((double) rs_length_diff);
1782 size_t copied_bytes = surviving_bytes;
1783 double cost_per_byte_ms = 0.0;
1784 if (copied_bytes > 0) {
1785 cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
1786 if (_in_marking_window)
1787 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1788 else
1789 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1790 }
1792 double all_other_time_ms = pause_time_ms -
1793 (update_rs_time + scan_only_time + scan_rs_time + obj_copy_time +
1794 _mark_closure_time_ms + termination_time);
1796 double young_other_time_ms = 0.0;
1797 if (_recorded_young_regions > 0) {
1798 young_other_time_ms =
1799 _recorded_young_cset_choice_time_ms +
1800 _recorded_young_free_cset_time_ms;
1801 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1802 (double) _recorded_young_regions);
1803 }
1804 double non_young_other_time_ms = 0.0;
1805 if (_recorded_non_young_regions > 0) {
1806 non_young_other_time_ms =
1807 _recorded_non_young_cset_choice_time_ms +
1808 _recorded_non_young_free_cset_time_ms;
1810 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1811 (double) _recorded_non_young_regions);
1812 }
1814 double constant_other_time_ms = all_other_time_ms -
1815 (young_other_time_ms + non_young_other_time_ms);
1816 _constant_other_time_ms_seq->add(constant_other_time_ms);
1818 double survival_ratio = 0.0;
1819 if (_bytes_in_collection_set_before_gc > 0) {
1820 survival_ratio = (double) bytes_in_to_space_during_gc() /
1821 (double) _bytes_in_collection_set_before_gc;
1822 }
1824 _pending_cards_seq->add((double) _pending_cards);
1825 _scanned_cards_seq->add((double) cards_scanned);
1826 _rs_lengths_seq->add((double) _max_rs_lengths);
1828 double expensive_region_limit_ms =
1829 (double) G1MaxPauseTimeMS - predict_constant_other_time_ms();
1830 if (expensive_region_limit_ms < 0.0) {
1831 // this means that the other time was predicted to be longer than
1832 // than the max pause time
1833 expensive_region_limit_ms = (double) G1MaxPauseTimeMS;
1834 }
1835 _expensive_region_limit_ms = expensive_region_limit_ms;
1837 if (PREDICTIONS_VERBOSE) {
1838 gclog_or_tty->print_cr("");
1839 gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
1840 "REGIONS %d %d %d %d "
1841 "PENDING_CARDS %d %d "
1842 "CARDS_SCANNED %d %d "
1843 "RS_LENGTHS %d %d "
1844 "SCAN_ONLY_SCAN %1.6lf %1.6lf "
1845 "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
1846 "SURVIVAL_RATIO %1.6lf %1.6lf "
1847 "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
1848 "OTHER_YOUNG %1.6lf %1.6lf "
1849 "OTHER_NON_YOUNG %1.6lf %1.6lf "
1850 "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
1851 "ELAPSED %1.6lf %1.6lf ",
1852 _cur_collection_start_sec,
1853 (!_last_young_gc_full) ? 2 :
1854 (last_pause_included_initial_mark) ? 1 : 0,
1855 _recorded_region_num,
1856 _recorded_young_regions,
1857 _recorded_scan_only_regions,
1858 _recorded_non_young_regions,
1859 _predicted_pending_cards, _pending_cards,
1860 _predicted_cards_scanned, cards_scanned,
1861 _predicted_rs_lengths, _max_rs_lengths,
1862 _predicted_scan_only_scan_time_ms, scan_only_time,
1863 _predicted_rs_update_time_ms, update_rs_time,
1864 _predicted_rs_scan_time_ms, scan_rs_time,
1865 _predicted_survival_ratio, survival_ratio,
1866 _predicted_object_copy_time_ms, obj_copy_time,
1867 _predicted_constant_other_time_ms, constant_other_time_ms,
1868 _predicted_young_other_time_ms, young_other_time_ms,
1869 _predicted_non_young_other_time_ms,
1870 non_young_other_time_ms,
1871 _vtime_diff_ms, termination_time,
1872 _predicted_pause_time_ms, elapsed_ms);
1873 }
1875 if (G1PolicyVerbose > 0) {
1876 gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
1877 _predicted_pause_time_ms,
1878 (_within_target) ? "within" : "outside",
1879 elapsed_ms);
1880 }
1882 }
1884 _in_marking_window = new_in_marking_window;
1885 _in_marking_window_im = new_in_marking_window_im;
1886 _free_regions_at_end_of_collection = _g1->free_regions();
1887 _scan_only_regions_at_end_of_collection = _g1->young_list_length();
1888 calculate_young_list_min_length();
1889 calculate_young_list_target_config();
1891 // </NEW PREDICTION>
1893 _target_pause_time_ms = -1.0;
1894 }
1896 // <NEW PREDICTION>
1898 double
1899 G1CollectorPolicy::
1900 predict_young_collection_elapsed_time_ms(size_t adjustment) {
1901 guarantee( adjustment == 0 || adjustment == 1, "invariant" );
1903 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1904 size_t young_num = g1h->young_list_length();
1905 if (young_num == 0)
1906 return 0.0;
1908 young_num += adjustment;
1909 size_t pending_cards = predict_pending_cards();
1910 size_t rs_lengths = g1h->young_list_sampled_rs_lengths() +
1911 predict_rs_length_diff();
1912 size_t card_num;
1913 if (full_young_gcs())
1914 card_num = predict_young_card_num(rs_lengths);
1915 else
1916 card_num = predict_non_young_card_num(rs_lengths);
1917 size_t young_byte_size = young_num * HeapRegion::GrainBytes;
1918 double accum_yg_surv_rate =
1919 _short_lived_surv_rate_group->accum_surv_rate(adjustment);
1921 size_t bytes_to_copy =
1922 (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
1924 return
1925 predict_rs_update_time_ms(pending_cards) +
1926 predict_rs_scan_time_ms(card_num) +
1927 predict_object_copy_time_ms(bytes_to_copy) +
1928 predict_young_other_time_ms(young_num) +
1929 predict_constant_other_time_ms();
1930 }
1932 double
1933 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1934 size_t rs_length = predict_rs_length_diff();
1935 size_t card_num;
1936 if (full_young_gcs())
1937 card_num = predict_young_card_num(rs_length);
1938 else
1939 card_num = predict_non_young_card_num(rs_length);
1940 return predict_base_elapsed_time_ms(pending_cards, card_num);
1941 }
1943 double
1944 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1945 size_t scanned_cards) {
1946 return
1947 predict_rs_update_time_ms(pending_cards) +
1948 predict_rs_scan_time_ms(scanned_cards) +
1949 predict_constant_other_time_ms();
1950 }
1952 double
1953 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1954 bool young) {
1955 size_t rs_length = hr->rem_set()->occupied();
1956 size_t card_num;
1957 if (full_young_gcs())
1958 card_num = predict_young_card_num(rs_length);
1959 else
1960 card_num = predict_non_young_card_num(rs_length);
1961 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1963 double region_elapsed_time_ms =
1964 predict_rs_scan_time_ms(card_num) +
1965 predict_object_copy_time_ms(bytes_to_copy);
1967 if (young)
1968 region_elapsed_time_ms += predict_young_other_time_ms(1);
1969 else
1970 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1972 return region_elapsed_time_ms;
1973 }
1975 size_t
1976 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1977 size_t bytes_to_copy;
1978 if (hr->is_marked())
1979 bytes_to_copy = hr->max_live_bytes();
1980 else {
1981 guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
1982 "invariant" );
1983 int age = hr->age_in_surv_rate_group();
1984 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1985 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1986 }
1988 return bytes_to_copy;
1989 }
1991 void
1992 G1CollectorPolicy::start_recording_regions() {
1993 _recorded_rs_lengths = 0;
1994 _recorded_scan_only_regions = 0;
1995 _recorded_young_regions = 0;
1996 _recorded_non_young_regions = 0;
1998 #if PREDICTIONS_VERBOSE
1999 _predicted_rs_lengths = 0;
2000 _predicted_cards_scanned = 0;
2002 _recorded_marked_bytes = 0;
2003 _recorded_young_bytes = 0;
2004 _predicted_bytes_to_copy = 0;
2005 #endif // PREDICTIONS_VERBOSE
2006 }
2008 void
2009 G1CollectorPolicy::record_cset_region(HeapRegion* hr, bool young) {
2010 if (young) {
2011 ++_recorded_young_regions;
2012 } else {
2013 ++_recorded_non_young_regions;
2014 }
2015 #if PREDICTIONS_VERBOSE
2016 if (young) {
2017 _recorded_young_bytes += hr->used();
2018 } else {
2019 _recorded_marked_bytes += hr->max_live_bytes();
2020 }
2021 _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
2022 #endif // PREDICTIONS_VERBOSE
2024 size_t rs_length = hr->rem_set()->occupied();
2025 _recorded_rs_lengths += rs_length;
2026 }
2028 void
2029 G1CollectorPolicy::record_scan_only_regions(size_t scan_only_length) {
2030 _recorded_scan_only_regions = scan_only_length;
2031 }
2033 void
2034 G1CollectorPolicy::end_recording_regions() {
2035 #if PREDICTIONS_VERBOSE
2036 _predicted_pending_cards = predict_pending_cards();
2037 _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
2038 if (full_young_gcs())
2039 _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
2040 else
2041 _predicted_cards_scanned +=
2042 predict_non_young_card_num(_predicted_rs_lengths);
2043 _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
2045 _predicted_scan_only_scan_time_ms =
2046 predict_scan_only_time_ms(_recorded_scan_only_regions);
2047 _predicted_rs_update_time_ms =
2048 predict_rs_update_time_ms(_g1->pending_card_num());
2049 _predicted_rs_scan_time_ms =
2050 predict_rs_scan_time_ms(_predicted_cards_scanned);
2051 _predicted_object_copy_time_ms =
2052 predict_object_copy_time_ms(_predicted_bytes_to_copy);
2053 _predicted_constant_other_time_ms =
2054 predict_constant_other_time_ms();
2055 _predicted_young_other_time_ms =
2056 predict_young_other_time_ms(_recorded_young_regions);
2057 _predicted_non_young_other_time_ms =
2058 predict_non_young_other_time_ms(_recorded_non_young_regions);
2060 _predicted_pause_time_ms =
2061 _predicted_scan_only_scan_time_ms +
2062 _predicted_rs_update_time_ms +
2063 _predicted_rs_scan_time_ms +
2064 _predicted_object_copy_time_ms +
2065 _predicted_constant_other_time_ms +
2066 _predicted_young_other_time_ms +
2067 _predicted_non_young_other_time_ms;
2068 #endif // PREDICTIONS_VERBOSE
2069 }
2071 void G1CollectorPolicy::check_if_region_is_too_expensive(double
2072 predicted_time_ms) {
2073 // I don't think we need to do this when in young GC mode since
2074 // marking will be initiated next time we hit the soft limit anyway...
2075 if (predicted_time_ms > _expensive_region_limit_ms) {
2076 if (!in_young_gc_mode()) {
2077 set_full_young_gcs(true);
2078 _should_initiate_conc_mark = true;
2079 } else
2080 // no point in doing another partial one
2081 _should_revert_to_full_young_gcs = true;
2082 }
2083 }
2085 // </NEW PREDICTION>
2088 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
2089 double elapsed_ms) {
2090 _recent_gc_times_ms->add(elapsed_ms);
2091 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
2092 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
2093 }
2095 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
2096 if (_recent_pause_times_ms->num() == 0) return (double) G1MaxPauseTimeMS;
2097 else return _recent_pause_times_ms->avg();
2098 }
2100 double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() {
2101 if (_recent_CH_strong_roots_times_ms->num() == 0)
2102 return (double)G1MaxPauseTimeMS/3.0;
2103 else return _recent_CH_strong_roots_times_ms->avg();
2104 }
2106 double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() {
2107 if (_recent_G1_strong_roots_times_ms->num() == 0)
2108 return (double)G1MaxPauseTimeMS/3.0;
2109 else return _recent_G1_strong_roots_times_ms->avg();
2110 }
2112 double G1CollectorPolicy::recent_avg_time_for_evac_ms() {
2113 if (_recent_evac_times_ms->num() == 0) return (double)G1MaxPauseTimeMS/3.0;
2114 else return _recent_evac_times_ms->avg();
2115 }
2117 int G1CollectorPolicy::number_of_recent_gcs() {
2118 assert(_recent_CH_strong_roots_times_ms->num() ==
2119 _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync");
2120 assert(_recent_G1_strong_roots_times_ms->num() ==
2121 _recent_evac_times_ms->num(), "Sequence out of sync");
2122 assert(_recent_evac_times_ms->num() ==
2123 _recent_pause_times_ms->num(), "Sequence out of sync");
2124 assert(_recent_pause_times_ms->num() ==
2125 _recent_CS_bytes_used_before->num(), "Sequence out of sync");
2126 assert(_recent_CS_bytes_used_before->num() ==
2127 _recent_CS_bytes_surviving->num(), "Sequence out of sync");
2128 return _recent_pause_times_ms->num();
2129 }
2131 double G1CollectorPolicy::recent_avg_survival_fraction() {
2132 return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
2133 _recent_CS_bytes_used_before);
2134 }
2136 double G1CollectorPolicy::last_survival_fraction() {
2137 return last_survival_fraction_work(_recent_CS_bytes_surviving,
2138 _recent_CS_bytes_used_before);
2139 }
2141 double
2142 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
2143 TruncatedSeq* before) {
2144 assert(surviving->num() == before->num(), "Sequence out of sync");
2145 if (before->sum() > 0.0) {
2146 double recent_survival_rate = surviving->sum() / before->sum();
2147 // We exempt parallel collection from this check because Alloc Buffer
2148 // fragmentation can produce negative collections.
2149 // Further, we're now always doing parallel collection. But I'm still
2150 // leaving this here as a placeholder for a more precise assertion later.
2151 // (DLD, 10/05.)
2152 assert((true || ParallelGCThreads > 0) ||
2153 _g1->evacuation_failed() ||
2154 recent_survival_rate <= 1.0, "Or bad frac");
2155 return recent_survival_rate;
2156 } else {
2157 return 1.0; // Be conservative.
2158 }
2159 }
2161 double
2162 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
2163 TruncatedSeq* before) {
2164 assert(surviving->num() == before->num(), "Sequence out of sync");
2165 if (surviving->num() > 0 && before->last() > 0.0) {
2166 double last_survival_rate = surviving->last() / before->last();
2167 // We exempt parallel collection from this check because Alloc Buffer
2168 // fragmentation can produce negative collections.
2169 // Further, we're now always doing parallel collection. But I'm still
2170 // leaving this here as a placeholder for a more precise assertion later.
2171 // (DLD, 10/05.)
2172 assert((true || ParallelGCThreads > 0) ||
2173 last_survival_rate <= 1.0, "Or bad frac");
2174 return last_survival_rate;
2175 } else {
2176 return 1.0;
2177 }
2178 }
2180 static const int survival_min_obs = 5;
2181 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
2182 static const double min_survival_rate = 0.1;
2184 double
2185 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
2186 double latest) {
2187 double res = avg;
2188 if (number_of_recent_gcs() < survival_min_obs) {
2189 res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
2190 }
2191 res = MAX2(res, latest);
2192 res = MAX2(res, min_survival_rate);
2193 // In the parallel case, LAB fragmentation can produce "negative
2194 // collections"; so can evac failure. Cap at 1.0
2195 res = MIN2(res, 1.0);
2196 return res;
2197 }
2199 size_t G1CollectorPolicy::expansion_amount() {
2200 if ((int)(recent_avg_pause_time_ratio() * 100.0) > G1GCPct) {
2201 // We will double the existing space, or take G1ExpandByPctOfAvail % of
2202 // the available expansion space, whichever is smaller, bounded below
2203 // by a minimum expansion (unless that's all that's left.)
2204 const size_t min_expand_bytes = 1*M;
2205 size_t reserved_bytes = _g1->g1_reserved_obj_bytes();
2206 size_t committed_bytes = _g1->capacity();
2207 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
2208 size_t expand_bytes;
2209 size_t expand_bytes_via_pct =
2210 uncommitted_bytes * G1ExpandByPctOfAvail / 100;
2211 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
2212 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
2213 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
2214 if (G1PolicyVerbose > 1) {
2215 gclog_or_tty->print("Decided to expand: ratio = %5.2f, "
2216 "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n"
2217 " Answer = %d.\n",
2218 recent_avg_pause_time_ratio(),
2219 byte_size_in_proper_unit(committed_bytes),
2220 proper_unit_for_byte_size(committed_bytes),
2221 byte_size_in_proper_unit(uncommitted_bytes),
2222 proper_unit_for_byte_size(uncommitted_bytes),
2223 byte_size_in_proper_unit(expand_bytes_via_pct),
2224 proper_unit_for_byte_size(expand_bytes_via_pct),
2225 byte_size_in_proper_unit(expand_bytes),
2226 proper_unit_for_byte_size(expand_bytes));
2227 }
2228 return expand_bytes;
2229 } else {
2230 return 0;
2231 }
2232 }
2234 void G1CollectorPolicy::note_start_of_mark_thread() {
2235 _mark_thread_startup_sec = os::elapsedTime();
2236 }
2238 class CountCSClosure: public HeapRegionClosure {
2239 G1CollectorPolicy* _g1_policy;
2240 public:
2241 CountCSClosure(G1CollectorPolicy* g1_policy) :
2242 _g1_policy(g1_policy) {}
2243 bool doHeapRegion(HeapRegion* r) {
2244 _g1_policy->_bytes_in_collection_set_before_gc += r->used();
2245 return false;
2246 }
2247 };
2249 void G1CollectorPolicy::count_CS_bytes_used() {
2250 CountCSClosure cs_closure(this);
2251 _g1->collection_set_iterate(&cs_closure);
2252 }
2254 static void print_indent(int level) {
2255 for (int j = 0; j < level+1; ++j)
2256 gclog_or_tty->print(" ");
2257 }
2259 void G1CollectorPolicy::print_summary (int level,
2260 const char* str,
2261 NumberSeq* seq) const {
2262 double sum = seq->sum();
2263 print_indent(level);
2264 gclog_or_tty->print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
2265 str, sum / 1000.0, seq->avg());
2266 }
2268 void G1CollectorPolicy::print_summary_sd (int level,
2269 const char* str,
2270 NumberSeq* seq) const {
2271 print_summary(level, str, seq);
2272 print_indent(level + 5);
2273 gclog_or_tty->print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2274 seq->num(), seq->sd(), seq->maximum());
2275 }
2277 void G1CollectorPolicy::check_other_times(int level,
2278 NumberSeq* other_times_ms,
2279 NumberSeq* calc_other_times_ms) const {
2280 bool should_print = false;
2282 double max_sum = MAX2(fabs(other_times_ms->sum()),
2283 fabs(calc_other_times_ms->sum()));
2284 double min_sum = MIN2(fabs(other_times_ms->sum()),
2285 fabs(calc_other_times_ms->sum()));
2286 double sum_ratio = max_sum / min_sum;
2287 if (sum_ratio > 1.1) {
2288 should_print = true;
2289 print_indent(level + 1);
2290 gclog_or_tty->print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
2291 }
2293 double max_avg = MAX2(fabs(other_times_ms->avg()),
2294 fabs(calc_other_times_ms->avg()));
2295 double min_avg = MIN2(fabs(other_times_ms->avg()),
2296 fabs(calc_other_times_ms->avg()));
2297 double avg_ratio = max_avg / min_avg;
2298 if (avg_ratio > 1.1) {
2299 should_print = true;
2300 print_indent(level + 1);
2301 gclog_or_tty->print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
2302 }
2304 if (other_times_ms->sum() < -0.01) {
2305 print_indent(level + 1);
2306 gclog_or_tty->print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
2307 }
2309 if (other_times_ms->avg() < -0.01) {
2310 print_indent(level + 1);
2311 gclog_or_tty->print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
2312 }
2314 if (calc_other_times_ms->sum() < -0.01) {
2315 should_print = true;
2316 print_indent(level + 1);
2317 gclog_or_tty->print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
2318 }
2320 if (calc_other_times_ms->avg() < -0.01) {
2321 should_print = true;
2322 print_indent(level + 1);
2323 gclog_or_tty->print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
2324 }
2326 if (should_print)
2327 print_summary(level, "Other(Calc)", calc_other_times_ms);
2328 }
2330 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
2331 bool parallel = ParallelGCThreads > 0;
2332 MainBodySummary* body_summary = summary->main_body_summary();
2333 if (summary->get_total_seq()->num() > 0) {
2334 print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
2335 if (body_summary != NULL) {
2336 print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
2337 if (parallel) {
2338 print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
2339 print_summary(2, "Update RS", body_summary->get_update_rs_seq());
2340 print_summary(2, "Ext Root Scanning",
2341 body_summary->get_ext_root_scan_seq());
2342 print_summary(2, "Mark Stack Scanning",
2343 body_summary->get_mark_stack_scan_seq());
2344 print_summary(2, "Scan-Only Scanning",
2345 body_summary->get_scan_only_seq());
2346 print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
2347 print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
2348 print_summary(2, "Termination", body_summary->get_termination_seq());
2349 print_summary(2, "Other", body_summary->get_parallel_other_seq());
2350 {
2351 NumberSeq* other_parts[] = {
2352 body_summary->get_update_rs_seq(),
2353 body_summary->get_ext_root_scan_seq(),
2354 body_summary->get_mark_stack_scan_seq(),
2355 body_summary->get_scan_only_seq(),
2356 body_summary->get_scan_rs_seq(),
2357 body_summary->get_obj_copy_seq(),
2358 body_summary->get_termination_seq()
2359 };
2360 NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
2361 7, other_parts);
2362 check_other_times(2, body_summary->get_parallel_other_seq(),
2363 &calc_other_times_ms);
2364 }
2365 print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
2366 print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
2367 } else {
2368 print_summary(1, "Update RS", body_summary->get_update_rs_seq());
2369 print_summary(1, "Ext Root Scanning",
2370 body_summary->get_ext_root_scan_seq());
2371 print_summary(1, "Mark Stack Scanning",
2372 body_summary->get_mark_stack_scan_seq());
2373 print_summary(1, "Scan-Only Scanning",
2374 body_summary->get_scan_only_seq());
2375 print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
2376 print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
2377 }
2378 }
2379 print_summary(1, "Other", summary->get_other_seq());
2380 {
2381 NumberSeq calc_other_times_ms;
2382 if (body_summary != NULL) {
2383 // not abandoned
2384 if (parallel) {
2385 // parallel
2386 NumberSeq* other_parts[] = {
2387 body_summary->get_satb_drain_seq(),
2388 body_summary->get_parallel_seq(),
2389 body_summary->get_clear_ct_seq()
2390 };
2391 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2392 3, other_parts);
2393 } else {
2394 // serial
2395 NumberSeq* other_parts[] = {
2396 body_summary->get_satb_drain_seq(),
2397 body_summary->get_update_rs_seq(),
2398 body_summary->get_ext_root_scan_seq(),
2399 body_summary->get_mark_stack_scan_seq(),
2400 body_summary->get_scan_only_seq(),
2401 body_summary->get_scan_rs_seq(),
2402 body_summary->get_obj_copy_seq()
2403 };
2404 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2405 7, other_parts);
2406 }
2407 } else {
2408 // abandoned
2409 calc_other_times_ms = NumberSeq();
2410 }
2411 check_other_times(1, summary->get_other_seq(), &calc_other_times_ms);
2412 }
2413 } else {
2414 print_indent(0);
2415 gclog_or_tty->print_cr("none");
2416 }
2417 gclog_or_tty->print_cr("");
2418 }
2420 void
2421 G1CollectorPolicy::print_abandoned_summary(PauseSummary* summary) const {
2422 bool printed = false;
2423 if (summary->get_total_seq()->num() > 0) {
2424 printed = true;
2425 print_summary(summary);
2426 }
2427 if (!printed) {
2428 print_indent(0);
2429 gclog_or_tty->print_cr("none");
2430 gclog_or_tty->print_cr("");
2431 }
2432 }
2434 void G1CollectorPolicy::print_tracing_info() const {
2435 if (TraceGen0Time) {
2436 gclog_or_tty->print_cr("ALL PAUSES");
2437 print_summary_sd(0, "Total", _all_pause_times_ms);
2438 gclog_or_tty->print_cr("");
2439 gclog_or_tty->print_cr("");
2440 gclog_or_tty->print_cr(" Full Young GC Pauses: %8d", _full_young_pause_num);
2441 gclog_or_tty->print_cr(" Partial Young GC Pauses: %8d", _partial_young_pause_num);
2442 gclog_or_tty->print_cr("");
2444 gclog_or_tty->print_cr("EVACUATION PAUSES");
2445 print_summary(_summary);
2447 gclog_or_tty->print_cr("ABANDONED PAUSES");
2448 print_abandoned_summary(_abandoned_summary);
2450 gclog_or_tty->print_cr("MISC");
2451 print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
2452 print_summary_sd(0, "Yields", _all_yield_times_ms);
2453 for (int i = 0; i < _aux_num; ++i) {
2454 if (_all_aux_times_ms[i].num() > 0) {
2455 char buffer[96];
2456 sprintf(buffer, "Aux%d", i);
2457 print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
2458 }
2459 }
2461 size_t all_region_num = _region_num_young + _region_num_tenured;
2462 gclog_or_tty->print_cr(" New Regions %8d, Young %8d (%6.2lf%%), "
2463 "Tenured %8d (%6.2lf%%)",
2464 all_region_num,
2465 _region_num_young,
2466 (double) _region_num_young / (double) all_region_num * 100.0,
2467 _region_num_tenured,
2468 (double) _region_num_tenured / (double) all_region_num * 100.0);
2470 if (!G1RSBarrierUseQueue) {
2471 gclog_or_tty->print_cr("Of %d times conc refinement was enabled, %d (%7.2f%%) "
2472 "did zero traversals.",
2473 _conc_refine_enabled, _conc_refine_zero_traversals,
2474 _conc_refine_enabled > 0 ?
2475 100.0 * (float)_conc_refine_zero_traversals/
2476 (float)_conc_refine_enabled : 0.0);
2477 gclog_or_tty->print_cr(" Max # of traversals = %d.",
2478 _conc_refine_max_traversals);
2479 gclog_or_tty->print_cr("");
2480 }
2481 }
2482 if (TraceGen1Time) {
2483 if (_all_full_gc_times_ms->num() > 0) {
2484 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2485 _all_full_gc_times_ms->num(),
2486 _all_full_gc_times_ms->sum() / 1000.0);
2487 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
2488 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2489 _all_full_gc_times_ms->sd(),
2490 _all_full_gc_times_ms->maximum());
2491 }
2492 }
2493 }
2495 void G1CollectorPolicy::print_yg_surv_rate_info() const {
2496 #ifndef PRODUCT
2497 _short_lived_surv_rate_group->print_surv_rate_summary();
2498 // add this call for any other surv rate groups
2499 #endif // PRODUCT
2500 }
2502 void G1CollectorPolicy::update_conc_refine_data() {
2503 unsigned traversals = _g1->concurrent_g1_refine()->disable();
2504 if (traversals == 0) _conc_refine_zero_traversals++;
2505 _conc_refine_max_traversals = MAX2(_conc_refine_max_traversals,
2506 (size_t)traversals);
2508 if (G1PolicyVerbose > 1)
2509 gclog_or_tty->print_cr("Did a CR traversal series: %d traversals.", traversals);
2510 double multiplier = 1.0;
2511 if (traversals == 0) {
2512 multiplier = 4.0;
2513 } else if (traversals > (size_t)G1ConcRefineTargTraversals) {
2514 multiplier = 1.0/1.5;
2515 } else if (traversals < (size_t)G1ConcRefineTargTraversals) {
2516 multiplier = 1.5;
2517 }
2518 if (G1PolicyVerbose > 1) {
2519 gclog_or_tty->print_cr(" Multiplier = %7.2f.", multiplier);
2520 gclog_or_tty->print(" Delta went from %d regions to ",
2521 _conc_refine_current_delta);
2522 }
2523 _conc_refine_current_delta =
2524 MIN2(_g1->n_regions(),
2525 (size_t)(_conc_refine_current_delta * multiplier));
2526 _conc_refine_current_delta =
2527 MAX2(_conc_refine_current_delta, (size_t)1);
2528 if (G1PolicyVerbose > 1) {
2529 gclog_or_tty->print_cr("%d regions.", _conc_refine_current_delta);
2530 }
2531 _conc_refine_enabled++;
2532 }
2534 bool
2535 G1CollectorPolicy::should_add_next_region_to_young_list() {
2536 assert(in_young_gc_mode(), "should be in young GC mode");
2537 bool ret;
2538 size_t young_list_length = _g1->young_list_length();
2539 size_t young_list_max_length = _young_list_target_length;
2540 if (G1FixedEdenSize) {
2541 young_list_max_length -= _max_survivor_regions;
2542 }
2543 if (young_list_length < young_list_max_length) {
2544 ret = true;
2545 ++_region_num_young;
2546 } else {
2547 ret = false;
2548 ++_region_num_tenured;
2549 }
2551 return ret;
2552 }
2554 #ifndef PRODUCT
2555 // for debugging, bit of a hack...
2556 static char*
2557 region_num_to_mbs(int length) {
2558 static char buffer[64];
2559 double bytes = (double) (length * HeapRegion::GrainBytes);
2560 double mbs = bytes / (double) (1024 * 1024);
2561 sprintf(buffer, "%7.2lfMB", mbs);
2562 return buffer;
2563 }
2564 #endif // PRODUCT
2566 void
2567 G1CollectorPolicy::checkpoint_conc_overhead() {
2568 double conc_overhead = 0.0;
2569 if (G1AccountConcurrentOverhead)
2570 conc_overhead = COTracker::totalPredConcOverhead();
2571 _mmu_tracker->update_conc_overhead(conc_overhead);
2572 #if 0
2573 gclog_or_tty->print(" CO %1.4lf TARGET %1.4lf",
2574 conc_overhead, _mmu_tracker->max_gc_time());
2575 #endif
2576 }
2579 size_t G1CollectorPolicy::max_regions(int purpose) {
2580 switch (purpose) {
2581 case GCAllocForSurvived:
2582 return _max_survivor_regions;
2583 case GCAllocForTenured:
2584 return REGIONS_UNLIMITED;
2585 default:
2586 ShouldNotReachHere();
2587 return REGIONS_UNLIMITED;
2588 };
2589 }
2591 // Calculates survivor space parameters.
2592 void G1CollectorPolicy::calculate_survivors_policy()
2593 {
2594 if (!G1UseSurvivorSpace) {
2595 return;
2596 }
2597 if (G1FixedSurvivorSpaceSize == 0) {
2598 _max_survivor_regions = _young_list_target_length / SurvivorRatio;
2599 } else {
2600 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
2601 }
2603 if (G1FixedTenuringThreshold) {
2604 _tenuring_threshold = MaxTenuringThreshold;
2605 } else {
2606 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
2607 HeapRegion::GrainWords * _max_survivor_regions);
2608 }
2609 }
2611 bool
2612 G1CollectorPolicy_BestRegionsFirst::should_do_collection_pause(size_t
2613 word_size) {
2614 assert(_g1->regions_accounted_for(), "Region leakage!");
2615 // Initiate a pause when we reach the steady-state "used" target.
2616 size_t used_hard = (_g1->capacity() / 100) * G1SteadyStateUsed;
2617 size_t used_soft =
2618 MAX2((_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta),
2619 used_hard/2);
2620 size_t used = _g1->used();
2622 double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
2624 size_t young_list_length = _g1->young_list_length();
2625 size_t young_list_max_length = _young_list_target_length;
2626 if (G1FixedEdenSize) {
2627 young_list_max_length -= _max_survivor_regions;
2628 }
2629 bool reached_target_length = young_list_length >= young_list_max_length;
2631 if (in_young_gc_mode()) {
2632 if (reached_target_length) {
2633 assert( young_list_length > 0 && _g1->young_list_length() > 0,
2634 "invariant" );
2635 _target_pause_time_ms = max_pause_time_ms;
2636 return true;
2637 }
2638 } else {
2639 guarantee( false, "should not reach here" );
2640 }
2642 return false;
2643 }
2645 #ifndef PRODUCT
2646 class HRSortIndexIsOKClosure: public HeapRegionClosure {
2647 CollectionSetChooser* _chooser;
2648 public:
2649 HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
2650 _chooser(chooser) {}
2652 bool doHeapRegion(HeapRegion* r) {
2653 if (!r->continuesHumongous()) {
2654 assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
2655 }
2656 return false;
2657 }
2658 };
2660 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
2661 HRSortIndexIsOKClosure cl(_collectionSetChooser);
2662 _g1->heap_region_iterate(&cl);
2663 return true;
2664 }
2665 #endif
2667 void
2668 G1CollectorPolicy_BestRegionsFirst::
2669 record_collection_pause_start(double start_time_sec, size_t start_used) {
2670 G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
2671 }
2673 class NextNonCSElemFinder: public HeapRegionClosure {
2674 HeapRegion* _res;
2675 public:
2676 NextNonCSElemFinder(): _res(NULL) {}
2677 bool doHeapRegion(HeapRegion* r) {
2678 if (!r->in_collection_set()) {
2679 _res = r;
2680 return true;
2681 } else {
2682 return false;
2683 }
2684 }
2685 HeapRegion* res() { return _res; }
2686 };
2688 class KnownGarbageClosure: public HeapRegionClosure {
2689 CollectionSetChooser* _hrSorted;
2691 public:
2692 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
2693 _hrSorted(hrSorted)
2694 {}
2696 bool doHeapRegion(HeapRegion* r) {
2697 // We only include humongous regions in collection
2698 // sets when concurrent mark shows that their contained object is
2699 // unreachable.
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. We also don't include young regions because we *must*
2706 // include them in the next collection pause.
2707 if (!r->isHumongous() && !r->is_young()) {
2708 _hrSorted->addMarkedHeapRegion(r);
2709 }
2710 }
2711 return false;
2712 }
2713 };
2715 class ParKnownGarbageHRClosure: public HeapRegionClosure {
2716 CollectionSetChooser* _hrSorted;
2717 jint _marked_regions_added;
2718 jint _chunk_size;
2719 jint _cur_chunk_idx;
2720 jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
2721 int _worker;
2722 int _invokes;
2724 void get_new_chunk() {
2725 _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
2726 _cur_chunk_end = _cur_chunk_idx + _chunk_size;
2727 }
2728 void add_region(HeapRegion* r) {
2729 if (_cur_chunk_idx == _cur_chunk_end) {
2730 get_new_chunk();
2731 }
2732 assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
2733 _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
2734 _marked_regions_added++;
2735 _cur_chunk_idx++;
2736 }
2738 public:
2739 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
2740 jint chunk_size,
2741 int worker) :
2742 _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
2743 _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
2744 _invokes(0)
2745 {}
2747 bool doHeapRegion(HeapRegion* r) {
2748 // We only include humongous regions in collection
2749 // sets when concurrent mark shows that their contained object is
2750 // unreachable.
2751 _invokes++;
2753 // Do we have any marking information for this region?
2754 if (r->is_marked()) {
2755 // We don't include humongous regions in collection
2756 // sets because we collect them immediately at the end of a marking
2757 // cycle.
2758 // We also do not include young regions in collection sets
2759 if (!r->isHumongous() && !r->is_young()) {
2760 add_region(r);
2761 }
2762 }
2763 return false;
2764 }
2765 jint marked_regions_added() { return _marked_regions_added; }
2766 int invokes() { return _invokes; }
2767 };
2769 class ParKnownGarbageTask: public AbstractGangTask {
2770 CollectionSetChooser* _hrSorted;
2771 jint _chunk_size;
2772 G1CollectedHeap* _g1;
2773 public:
2774 ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
2775 AbstractGangTask("ParKnownGarbageTask"),
2776 _hrSorted(hrSorted), _chunk_size(chunk_size),
2777 _g1(G1CollectedHeap::heap())
2778 {}
2780 void work(int i) {
2781 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
2782 // Back to zero for the claim value.
2783 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
2784 HeapRegion::InitialClaimValue);
2785 jint regions_added = parKnownGarbageCl.marked_regions_added();
2786 _hrSorted->incNumMarkedHeapRegions(regions_added);
2787 if (G1PrintParCleanupStats) {
2788 gclog_or_tty->print(" Thread %d called %d times, added %d regions to list.\n",
2789 i, parKnownGarbageCl.invokes(), regions_added);
2790 }
2791 }
2792 };
2794 void
2795 G1CollectorPolicy_BestRegionsFirst::
2796 record_concurrent_mark_cleanup_end(size_t freed_bytes,
2797 size_t max_live_bytes) {
2798 double start;
2799 if (G1PrintParCleanupStats) start = os::elapsedTime();
2800 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
2802 _collectionSetChooser->clearMarkedHeapRegions();
2803 double clear_marked_end;
2804 if (G1PrintParCleanupStats) {
2805 clear_marked_end = os::elapsedTime();
2806 gclog_or_tty->print_cr(" clear marked regions + work1: %8.3f ms.",
2807 (clear_marked_end - start)*1000.0);
2808 }
2809 if (ParallelGCThreads > 0) {
2810 const size_t OverpartitionFactor = 4;
2811 const size_t MinChunkSize = 8;
2812 const size_t ChunkSize =
2813 MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
2814 MinChunkSize);
2815 _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
2816 ChunkSize);
2817 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
2818 (int) ChunkSize);
2819 _g1->workers()->run_task(&parKnownGarbageTask);
2821 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
2822 "sanity check");
2823 } else {
2824 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
2825 _g1->heap_region_iterate(&knownGarbagecl);
2826 }
2827 double known_garbage_end;
2828 if (G1PrintParCleanupStats) {
2829 known_garbage_end = os::elapsedTime();
2830 gclog_or_tty->print_cr(" compute known garbage: %8.3f ms.",
2831 (known_garbage_end - clear_marked_end)*1000.0);
2832 }
2833 _collectionSetChooser->sortMarkedHeapRegions();
2834 double sort_end;
2835 if (G1PrintParCleanupStats) {
2836 sort_end = os::elapsedTime();
2837 gclog_or_tty->print_cr(" sorting: %8.3f ms.",
2838 (sort_end - known_garbage_end)*1000.0);
2839 }
2841 record_concurrent_mark_cleanup_end_work2();
2842 double work2_end;
2843 if (G1PrintParCleanupStats) {
2844 work2_end = os::elapsedTime();
2845 gclog_or_tty->print_cr(" work2: %8.3f ms.",
2846 (work2_end - sort_end)*1000.0);
2847 }
2848 }
2850 // Add the heap region to the collection set and return the conservative
2851 // estimate of the number of live bytes.
2852 void G1CollectorPolicy::
2853 add_to_collection_set(HeapRegion* hr) {
2854 if (G1TraceRegions) {
2855 gclog_or_tty->print_cr("added region to cset %d:["PTR_FORMAT", "PTR_FORMAT"], "
2856 "top "PTR_FORMAT", young %s",
2857 hr->hrs_index(), hr->bottom(), hr->end(),
2858 hr->top(), (hr->is_young()) ? "YES" : "NO");
2859 }
2861 if (_g1->mark_in_progress())
2862 _g1->concurrent_mark()->registerCSetRegion(hr);
2864 assert(!hr->in_collection_set(),
2865 "should not already be in the CSet");
2866 hr->set_in_collection_set(true);
2867 hr->set_next_in_collection_set(_collection_set);
2868 _collection_set = hr;
2869 _collection_set_size++;
2870 _collection_set_bytes_used_before += hr->used();
2871 _g1->register_region_with_in_cset_fast_test(hr);
2872 }
2874 void
2875 G1CollectorPolicy_BestRegionsFirst::
2876 choose_collection_set() {
2877 double non_young_start_time_sec;
2878 start_recording_regions();
2880 guarantee(_target_pause_time_ms > -1.0,
2881 "_target_pause_time_ms should have been set!");
2882 assert(_collection_set == NULL, "Precondition");
2884 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2885 double predicted_pause_time_ms = base_time_ms;
2887 double target_time_ms = _target_pause_time_ms;
2888 double time_remaining_ms = target_time_ms - base_time_ms;
2890 // the 10% and 50% values are arbitrary...
2891 if (time_remaining_ms < 0.10*target_time_ms) {
2892 time_remaining_ms = 0.50 * target_time_ms;
2893 _within_target = false;
2894 } else {
2895 _within_target = true;
2896 }
2898 // We figure out the number of bytes available for future to-space.
2899 // For new regions without marking information, we must assume the
2900 // worst-case of complete survival. If we have marking information for a
2901 // region, we can bound the amount of live data. We can add a number of
2902 // such regions, as long as the sum of the live data bounds does not
2903 // exceed the available evacuation space.
2904 size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes;
2906 size_t expansion_bytes =
2907 _g1->expansion_regions() * HeapRegion::GrainBytes;
2909 _collection_set_bytes_used_before = 0;
2910 _collection_set_size = 0;
2912 // Adjust for expansion and slop.
2913 max_live_bytes = max_live_bytes + expansion_bytes;
2915 assert(_g1->regions_accounted_for(), "Region leakage!");
2917 HeapRegion* hr;
2918 if (in_young_gc_mode()) {
2919 double young_start_time_sec = os::elapsedTime();
2921 if (G1PolicyVerbose > 0) {
2922 gclog_or_tty->print_cr("Adding %d young regions to the CSet",
2923 _g1->young_list_length());
2924 }
2925 _young_cset_length = 0;
2926 _last_young_gc_full = full_young_gcs() ? true : false;
2927 if (_last_young_gc_full)
2928 ++_full_young_pause_num;
2929 else
2930 ++_partial_young_pause_num;
2931 hr = _g1->pop_region_from_young_list();
2932 while (hr != NULL) {
2934 assert( hr->young_index_in_cset() == -1, "invariant" );
2935 assert( hr->age_in_surv_rate_group() != -1, "invariant" );
2936 hr->set_young_index_in_cset((int) _young_cset_length);
2938 ++_young_cset_length;
2939 double predicted_time_ms = predict_region_elapsed_time_ms(hr, true);
2940 time_remaining_ms -= predicted_time_ms;
2941 predicted_pause_time_ms += predicted_time_ms;
2942 assert(!hr->in_collection_set(), "invariant");
2943 add_to_collection_set(hr);
2944 record_cset_region(hr, true);
2945 max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
2946 if (G1PolicyVerbose > 0) {
2947 gclog_or_tty->print_cr(" Added [" PTR_FORMAT ", " PTR_FORMAT") to CS.",
2948 hr->bottom(), hr->end());
2949 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2950 max_live_bytes/K);
2951 }
2952 hr = _g1->pop_region_from_young_list();
2953 }
2955 record_scan_only_regions(_g1->young_list_scan_only_length());
2957 double young_end_time_sec = os::elapsedTime();
2958 _recorded_young_cset_choice_time_ms =
2959 (young_end_time_sec - young_start_time_sec) * 1000.0;
2961 non_young_start_time_sec = os::elapsedTime();
2963 if (_young_cset_length > 0 && _last_young_gc_full) {
2964 // don't bother adding more regions...
2965 goto choose_collection_set_end;
2966 }
2967 }
2969 if (!in_young_gc_mode() || !full_young_gcs()) {
2970 bool should_continue = true;
2971 NumberSeq seq;
2972 double avg_prediction = 100000000000000000.0; // something very large
2973 do {
2974 hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
2975 avg_prediction);
2976 if (hr != NULL) {
2977 double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
2978 time_remaining_ms -= predicted_time_ms;
2979 predicted_pause_time_ms += predicted_time_ms;
2980 add_to_collection_set(hr);
2981 record_cset_region(hr, false);
2982 max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
2983 if (G1PolicyVerbose > 0) {
2984 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2985 max_live_bytes/K);
2986 }
2987 seq.add(predicted_time_ms);
2988 avg_prediction = seq.avg() + seq.sd();
2989 }
2990 should_continue =
2991 ( hr != NULL) &&
2992 ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0
2993 : _collection_set_size < _young_list_fixed_length );
2994 } while (should_continue);
2996 if (!adaptive_young_list_length() &&
2997 _collection_set_size < _young_list_fixed_length)
2998 _should_revert_to_full_young_gcs = true;
2999 }
3001 choose_collection_set_end:
3002 count_CS_bytes_used();
3004 end_recording_regions();
3006 double non_young_end_time_sec = os::elapsedTime();
3007 _recorded_non_young_cset_choice_time_ms =
3008 (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
3009 }
3011 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
3012 G1CollectorPolicy::record_full_collection_end();
3013 _collectionSetChooser->updateAfterFullCollection();
3014 }
3016 void G1CollectorPolicy_BestRegionsFirst::
3017 expand_if_possible(size_t numRegions) {
3018 size_t expansion_bytes = numRegions * HeapRegion::GrainBytes;
3019 _g1->expand(expansion_bytes);
3020 }
3022 void G1CollectorPolicy_BestRegionsFirst::
3023 record_collection_pause_end(bool abandoned) {
3024 G1CollectorPolicy::record_collection_pause_end(abandoned);
3025 assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
3026 }
3028 // Local Variables: ***
3029 // c-indentation-style: gnu ***
3030 // End: ***