Thu, 19 Nov 2009 10:19:19 -0800
6902701: G1: protect debugging code related to 6898948 with a debug flag
Summary: Protected stats dump with a new develop flag; other than for the dump, reconciled product and non-product behaviour in face of the error.
Reviewed-by: 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.
18 *
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
21 * have any questions.
22 *
23 */
25 #include "incls/_precompiled.incl"
26 #include "incls/_g1CollectorPolicy.cpp.incl"
28 #define PREDICTIONS_VERBOSE 0
30 // <NEW PREDICTION>
32 // Different defaults for different number of GC threads
33 // They were chosen by running GCOld and SPECjbb on debris with different
34 // numbers of GC threads and choosing them based on the results
36 // all the same
37 static double rs_length_diff_defaults[] = {
38 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
39 };
41 static double cost_per_card_ms_defaults[] = {
42 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
43 };
45 static double cost_per_scan_only_region_ms_defaults[] = {
46 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
47 };
49 // all the same
50 static double fully_young_cards_per_entry_ratio_defaults[] = {
51 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
52 };
54 static double cost_per_entry_ms_defaults[] = {
55 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
56 };
58 static double cost_per_byte_ms_defaults[] = {
59 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
60 };
62 // these should be pretty consistent
63 static double constant_other_time_ms_defaults[] = {
64 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
65 };
68 static double young_other_cost_per_region_ms_defaults[] = {
69 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
70 };
72 static double non_young_other_cost_per_region_ms_defaults[] = {
73 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
74 };
76 // </NEW PREDICTION>
78 G1CollectorPolicy::G1CollectorPolicy() :
79 _parallel_gc_threads((ParallelGCThreads > 0) ? ParallelGCThreads : 1),
80 _n_pauses(0),
81 _recent_CH_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
82 _recent_G1_strong_roots_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
83 _recent_evac_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
84 _recent_pause_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
85 _recent_rs_sizes(new TruncatedSeq(NumPrevPausesForHeuristics)),
86 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
87 _all_pause_times_ms(new NumberSeq()),
88 _stop_world_start(0.0),
89 _all_stop_world_times_ms(new NumberSeq()),
90 _all_yield_times_ms(new NumberSeq()),
92 _all_mod_union_times_ms(new NumberSeq()),
94 _summary(new Summary()),
95 _abandoned_summary(new AbandonedSummary()),
97 #ifndef PRODUCT
98 _cur_clear_ct_time_ms(0.0),
99 _min_clear_cc_time_ms(-1.0),
100 _max_clear_cc_time_ms(-1.0),
101 _cur_clear_cc_time_ms(0.0),
102 _cum_clear_cc_time_ms(0.0),
103 _num_cc_clears(0L),
104 #endif
106 _region_num_young(0),
107 _region_num_tenured(0),
108 _prev_region_num_young(0),
109 _prev_region_num_tenured(0),
111 _aux_num(10),
112 _all_aux_times_ms(new NumberSeq[_aux_num]),
113 _cur_aux_start_times_ms(new double[_aux_num]),
114 _cur_aux_times_ms(new double[_aux_num]),
115 _cur_aux_times_set(new bool[_aux_num]),
117 _concurrent_mark_init_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
118 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
119 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
121 // <NEW PREDICTION>
123 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
124 _prev_collection_pause_end_ms(0.0),
125 _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
126 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
127 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
128 _cost_per_scan_only_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
129 _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
130 _partially_young_cards_per_entry_ratio_seq(
131 new TruncatedSeq(TruncatedSeqLength)),
132 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
133 _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
134 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
135 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
136 _cost_per_scan_only_region_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
137 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
138 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
139 _non_young_other_cost_per_region_ms_seq(
140 new TruncatedSeq(TruncatedSeqLength)),
142 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
143 _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
144 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
146 _pause_time_target_ms((double) MaxGCPauseMillis),
148 // </NEW PREDICTION>
150 _in_young_gc_mode(false),
151 _full_young_gcs(true),
152 _full_young_pause_num(0),
153 _partial_young_pause_num(0),
155 _during_marking(false),
156 _in_marking_window(false),
157 _in_marking_window_im(false),
159 _known_garbage_ratio(0.0),
160 _known_garbage_bytes(0),
162 _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
163 _target_pause_time_ms(-1.0),
165 _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
167 _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
168 _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
170 _recent_avg_pause_time_ratio(0.0),
171 _num_markings(0),
172 _n_marks(0),
173 _n_pauses_at_mark_end(0),
175 _all_full_gc_times_ms(new NumberSeq()),
177 // G1PausesBtwnConcMark defaults to -1
178 // so the hack is to do the cast QQQ FIXME
179 _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
180 _n_marks_since_last_pause(0),
181 _conc_mark_initiated(false),
182 _should_initiate_conc_mark(false),
183 _should_revert_to_full_young_gcs(false),
184 _last_full_young_gc(false),
186 _prev_collection_pause_used_at_end_bytes(0),
188 _collection_set(NULL),
189 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
190 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
191 #endif // _MSC_VER
193 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
194 G1YoungSurvRateNumRegionsSummary)),
195 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
196 G1YoungSurvRateNumRegionsSummary)),
197 // add here any more surv rate groups
198 _recorded_survivor_regions(0),
199 _recorded_survivor_head(NULL),
200 _recorded_survivor_tail(NULL),
201 _survivors_age_table(true)
203 {
204 // Set up the region size and associated fields. Given that the
205 // policy is created before the heap, we have to set this up here,
206 // so it's done as soon as possible.
207 HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
209 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
210 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
212 _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
213 _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
214 _par_last_scan_only_times_ms = new double[_parallel_gc_threads];
215 _par_last_scan_only_regions_scanned = new double[_parallel_gc_threads];
217 _par_last_update_rs_start_times_ms = new double[_parallel_gc_threads];
218 _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
219 _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
221 _par_last_scan_rs_start_times_ms = new double[_parallel_gc_threads];
222 _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
223 _par_last_scan_new_refs_times_ms = new double[_parallel_gc_threads];
225 _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
227 _par_last_termination_times_ms = new double[_parallel_gc_threads];
229 // start conservatively
230 _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
232 // <NEW PREDICTION>
234 int index;
235 if (ParallelGCThreads == 0)
236 index = 0;
237 else if (ParallelGCThreads > 8)
238 index = 7;
239 else
240 index = ParallelGCThreads - 1;
242 _pending_card_diff_seq->add(0.0);
243 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
244 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
245 _cost_per_scan_only_region_ms_seq->add(
246 cost_per_scan_only_region_ms_defaults[index]);
247 _fully_young_cards_per_entry_ratio_seq->add(
248 fully_young_cards_per_entry_ratio_defaults[index]);
249 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
250 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
251 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
252 _young_other_cost_per_region_ms_seq->add(
253 young_other_cost_per_region_ms_defaults[index]);
254 _non_young_other_cost_per_region_ms_seq->add(
255 non_young_other_cost_per_region_ms_defaults[index]);
257 // </NEW PREDICTION>
259 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
260 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
261 guarantee(max_gc_time < time_slice,
262 "Max GC time should not be greater than the time slice");
263 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
264 _sigma = (double) G1ConfidencePercent / 100.0;
266 // start conservatively (around 50ms is about right)
267 _concurrent_mark_init_times_ms->add(0.05);
268 _concurrent_mark_remark_times_ms->add(0.05);
269 _concurrent_mark_cleanup_times_ms->add(0.20);
270 _tenuring_threshold = MaxTenuringThreshold;
272 if (G1UseSurvivorSpaces) {
273 // if G1FixedSurvivorSpaceSize is 0 which means the size is not
274 // fixed, then _max_survivor_regions will be calculated at
275 // calculate_young_list_target_config during initialization
276 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
277 } else {
278 _max_survivor_regions = 0;
279 }
281 initialize_all();
282 }
284 // Increment "i", mod "len"
285 static void inc_mod(int& i, int len) {
286 i++; if (i == len) i = 0;
287 }
289 void G1CollectorPolicy::initialize_flags() {
290 set_min_alignment(HeapRegion::GrainBytes);
291 set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
292 if (SurvivorRatio < 1) {
293 vm_exit_during_initialization("Invalid survivor ratio specified");
294 }
295 CollectorPolicy::initialize_flags();
296 }
298 void G1CollectorPolicy::init() {
299 // Set aside an initial future to_space.
300 _g1 = G1CollectedHeap::heap();
301 size_t regions = Universe::heap()->capacity() / HeapRegion::GrainBytes;
303 assert(Heap_lock->owned_by_self(), "Locking discipline.");
305 if (G1SteadyStateUsed < 50) {
306 vm_exit_during_initialization("G1SteadyStateUsed must be at least 50%.");
307 }
309 initialize_gc_policy_counters();
311 if (G1Gen) {
312 _in_young_gc_mode = true;
314 if (G1YoungGenSize == 0) {
315 set_adaptive_young_list_length(true);
316 _young_list_fixed_length = 0;
317 } else {
318 set_adaptive_young_list_length(false);
319 _young_list_fixed_length = (G1YoungGenSize / HeapRegion::GrainBytes);
320 }
321 _free_regions_at_end_of_collection = _g1->free_regions();
322 _scan_only_regions_at_end_of_collection = 0;
323 calculate_young_list_min_length();
324 guarantee( _young_list_min_length == 0, "invariant, not enough info" );
325 calculate_young_list_target_config();
326 } else {
327 _young_list_fixed_length = 0;
328 _in_young_gc_mode = false;
329 }
330 }
332 // Create the jstat counters for the policy.
333 void G1CollectorPolicy::initialize_gc_policy_counters()
334 {
335 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 2 + G1Gen);
336 }
338 void G1CollectorPolicy::calculate_young_list_min_length() {
339 _young_list_min_length = 0;
341 if (!adaptive_young_list_length())
342 return;
344 if (_alloc_rate_ms_seq->num() > 3) {
345 double now_sec = os::elapsedTime();
346 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
347 double alloc_rate_ms = predict_alloc_rate_ms();
348 int min_regions = (int) ceil(alloc_rate_ms * when_ms);
349 int current_region_num = (int) _g1->young_list_length();
350 _young_list_min_length = min_regions + current_region_num;
351 }
352 }
354 void G1CollectorPolicy::calculate_young_list_target_config() {
355 if (adaptive_young_list_length()) {
356 size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
357 calculate_young_list_target_config(rs_lengths);
358 } else {
359 if (full_young_gcs())
360 _young_list_target_length = _young_list_fixed_length;
361 else
362 _young_list_target_length = _young_list_fixed_length / 2;
363 _young_list_target_length = MAX2(_young_list_target_length, (size_t)1);
364 size_t so_length = calculate_optimal_so_length(_young_list_target_length);
365 guarantee( so_length < _young_list_target_length, "invariant" );
366 _young_list_so_prefix_length = so_length;
367 }
368 calculate_survivors_policy();
369 }
371 // This method calculate the optimal scan-only set for a fixed young
372 // gen size. I couldn't work out how to reuse the more elaborate one,
373 // i.e. calculate_young_list_target_config(rs_length), as the loops are
374 // fundamentally different (the other one finds a config for different
375 // S-O lengths, whereas here we need to do the opposite).
376 size_t G1CollectorPolicy::calculate_optimal_so_length(
377 size_t young_list_length) {
378 if (!G1UseScanOnlyPrefix)
379 return 0;
381 if (_all_pause_times_ms->num() < 3) {
382 // we won't use a scan-only set at the beginning to allow the rest
383 // of the predictors to warm up
384 return 0;
385 }
387 if (_cost_per_scan_only_region_ms_seq->num() < 3) {
388 // then, we'll only set the S-O set to 1 for a little bit of time,
389 // to get enough information on the scanning cost
390 return 1;
391 }
393 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
394 size_t rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
395 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
396 size_t scanned_cards;
397 if (full_young_gcs())
398 scanned_cards = predict_young_card_num(adj_rs_lengths);
399 else
400 scanned_cards = predict_non_young_card_num(adj_rs_lengths);
401 double base_time_ms = predict_base_elapsed_time_ms(pending_cards,
402 scanned_cards);
404 size_t so_length = 0;
405 double max_gc_eff = 0.0;
406 for (size_t i = 0; i < young_list_length; ++i) {
407 double gc_eff = 0.0;
408 double pause_time_ms = 0.0;
409 predict_gc_eff(young_list_length, i, base_time_ms,
410 &gc_eff, &pause_time_ms);
411 if (gc_eff > max_gc_eff) {
412 max_gc_eff = gc_eff;
413 so_length = i;
414 }
415 }
417 // set it to 95% of the optimal to make sure we sample the "area"
418 // around the optimal length to get up-to-date survival rate data
419 return so_length * 950 / 1000;
420 }
422 // This is a really cool piece of code! It finds the best
423 // target configuration (young length / scan-only prefix length) so
424 // that GC efficiency is maximized and that we also meet a pause
425 // time. It's a triple nested loop. These loops are explained below
426 // from the inside-out :-)
427 //
428 // (a) The innermost loop will try to find the optimal young length
429 // for a fixed S-O length. It uses a binary search to speed up the
430 // process. We assume that, for a fixed S-O length, as we add more
431 // young regions to the CSet, the GC efficiency will only go up (I'll
432 // skip the proof). So, using a binary search to optimize this process
433 // makes perfect sense.
434 //
435 // (b) The middle loop will fix the S-O length before calling the
436 // innermost one. It will vary it between two parameters, increasing
437 // it by a given increment.
438 //
439 // (c) The outermost loop will call the middle loop three times.
440 // (1) The first time it will explore all possible S-O length values
441 // from 0 to as large as it can get, using a coarse increment (to
442 // quickly "home in" to where the optimal seems to be).
443 // (2) The second time it will explore the values around the optimal
444 // that was found by the first iteration using a fine increment.
445 // (3) Once the optimal config has been determined by the second
446 // iteration, we'll redo the calculation, but setting the S-O length
447 // to 95% of the optimal to make sure we sample the "area"
448 // around the optimal length to get up-to-date survival rate data
449 //
450 // Termination conditions for the iterations are several: the pause
451 // time is over the limit, we do not have enough to-space, etc.
453 void G1CollectorPolicy::calculate_young_list_target_config(size_t rs_lengths) {
454 guarantee( adaptive_young_list_length(), "pre-condition" );
456 double start_time_sec = os::elapsedTime();
457 size_t min_reserve_perc = MAX2((size_t)2, (size_t)G1MinReservePercent);
458 min_reserve_perc = MIN2((size_t) 50, min_reserve_perc);
459 size_t reserve_regions =
460 (size_t) ((double) min_reserve_perc * (double) _g1->n_regions() / 100.0);
462 if (full_young_gcs() && _free_regions_at_end_of_collection > 0) {
463 // we are in fully-young mode and there are free regions in the heap
465 double survivor_regions_evac_time =
466 predict_survivor_regions_evac_time();
468 size_t min_so_length = 0;
469 size_t max_so_length = 0;
471 if (G1UseScanOnlyPrefix) {
472 if (_all_pause_times_ms->num() < 3) {
473 // we won't use a scan-only set at the beginning to allow the rest
474 // of the predictors to warm up
475 min_so_length = 0;
476 max_so_length = 0;
477 } else if (_cost_per_scan_only_region_ms_seq->num() < 3) {
478 // then, we'll only set the S-O set to 1 for a little bit of time,
479 // to get enough information on the scanning cost
480 min_so_length = 1;
481 max_so_length = 1;
482 } else if (_in_marking_window || _last_full_young_gc) {
483 // no S-O prefix during a marking phase either, as at the end
484 // of the marking phase we'll have to use a very small young
485 // length target to fill up the rest of the CSet with
486 // non-young regions and, if we have lots of scan-only regions
487 // left-over, we will not be able to add any more non-young
488 // regions.
489 min_so_length = 0;
490 max_so_length = 0;
491 } else {
492 // this is the common case; we'll never reach the maximum, we
493 // one of the end conditions will fire well before that
494 // (hopefully!)
495 min_so_length = 0;
496 max_so_length = _free_regions_at_end_of_collection - 1;
497 }
498 } else {
499 // no S-O prefix, as the switch is not set, but we still need to
500 // do one iteration to calculate the best young target that
501 // meets the pause time; this way we reuse the same code instead
502 // of replicating it
503 min_so_length = 0;
504 max_so_length = 0;
505 }
507 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
508 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
509 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
510 size_t scanned_cards;
511 if (full_young_gcs())
512 scanned_cards = predict_young_card_num(adj_rs_lengths);
513 else
514 scanned_cards = predict_non_young_card_num(adj_rs_lengths);
515 // calculate this once, so that we don't have to recalculate it in
516 // the innermost loop
517 double base_time_ms = predict_base_elapsed_time_ms(pending_cards, scanned_cards)
518 + survivor_regions_evac_time;
519 // the result
520 size_t final_young_length = 0;
521 size_t final_so_length = 0;
522 double final_gc_eff = 0.0;
523 // we'll also keep track of how many times we go into the inner loop
524 // this is for profiling reasons
525 size_t calculations = 0;
527 // this determines which of the three iterations the outer loop is in
528 typedef enum {
529 pass_type_coarse,
530 pass_type_fine,
531 pass_type_final
532 } pass_type_t;
534 // range of the outer loop's iteration
535 size_t from_so_length = min_so_length;
536 size_t to_so_length = max_so_length;
537 guarantee( from_so_length <= to_so_length, "invariant" );
539 // this will keep the S-O length that's found by the second
540 // iteration of the outer loop; we'll keep it just in case the third
541 // iteration fails to find something
542 size_t fine_so_length = 0;
544 // the increment step for the coarse (first) iteration
545 size_t so_coarse_increments = 5;
547 // the common case, we'll start with the coarse iteration
548 pass_type_t pass = pass_type_coarse;
549 size_t so_length_incr = so_coarse_increments;
551 if (from_so_length == to_so_length) {
552 // not point in doing the coarse iteration, we'll go directly into
553 // the fine one (we essentially trying to find the optimal young
554 // length for a fixed S-O length).
555 so_length_incr = 1;
556 pass = pass_type_final;
557 } else if (to_so_length - from_so_length < 3 * so_coarse_increments) {
558 // again, the range is too short so no point in foind the coarse
559 // iteration either
560 so_length_incr = 1;
561 pass = pass_type_fine;
562 }
564 bool done = false;
565 // this is the outermost loop
566 while (!done) {
567 #ifdef TRACE_CALC_YOUNG_CONFIG
568 // leave this in for debugging, just in case
569 gclog_or_tty->print_cr("searching between " SIZE_FORMAT " and " SIZE_FORMAT
570 ", incr " SIZE_FORMAT ", pass %s",
571 from_so_length, to_so_length, so_length_incr,
572 (pass == pass_type_coarse) ? "coarse" :
573 (pass == pass_type_fine) ? "fine" : "final");
574 #endif // TRACE_CALC_YOUNG_CONFIG
576 size_t so_length = from_so_length;
577 size_t init_free_regions =
578 MAX2((size_t)0,
579 _free_regions_at_end_of_collection +
580 _scan_only_regions_at_end_of_collection - reserve_regions);
582 // this determines whether a configuration was found
583 bool gc_eff_set = false;
584 // this is the middle loop
585 while (so_length <= to_so_length) {
586 // base time, which excludes region-related time; again we
587 // calculate it once to avoid recalculating it in the
588 // innermost loop
589 double base_time_with_so_ms =
590 base_time_ms + predict_scan_only_time_ms(so_length);
591 // it's already over the pause target, go around
592 if (base_time_with_so_ms > target_pause_time_ms)
593 break;
595 size_t starting_young_length = so_length+1;
597 // we make sure that the short young length that makes sense
598 // (one more than the S-O length) is feasible
599 size_t min_young_length = starting_young_length;
600 double min_gc_eff;
601 bool min_ok;
602 ++calculations;
603 min_ok = predict_gc_eff(min_young_length, so_length,
604 base_time_with_so_ms,
605 init_free_regions, target_pause_time_ms,
606 &min_gc_eff);
608 if (min_ok) {
609 // the shortest young length is indeed feasible; we'll know
610 // set up the max young length and we'll do a binary search
611 // between min_young_length and max_young_length
612 size_t max_young_length = _free_regions_at_end_of_collection - 1;
613 double max_gc_eff = 0.0;
614 bool max_ok = false;
616 // the innermost loop! (finally!)
617 while (max_young_length > min_young_length) {
618 // we'll make sure that min_young_length is always at a
619 // feasible config
620 guarantee( min_ok, "invariant" );
622 ++calculations;
623 max_ok = predict_gc_eff(max_young_length, so_length,
624 base_time_with_so_ms,
625 init_free_regions, target_pause_time_ms,
626 &max_gc_eff);
628 size_t diff = (max_young_length - min_young_length) / 2;
629 if (max_ok) {
630 min_young_length = max_young_length;
631 min_gc_eff = max_gc_eff;
632 min_ok = true;
633 }
634 max_young_length = min_young_length + diff;
635 }
637 // the innermost loop found a config
638 guarantee( min_ok, "invariant" );
639 if (min_gc_eff > final_gc_eff) {
640 // it's the best config so far, so we'll keep it
641 final_gc_eff = min_gc_eff;
642 final_young_length = min_young_length;
643 final_so_length = so_length;
644 gc_eff_set = true;
645 }
646 }
648 // incremental the fixed S-O length and go around
649 so_length += so_length_incr;
650 }
652 // this is the end of the outermost loop and we need to decide
653 // what to do during the next iteration
654 if (pass == pass_type_coarse) {
655 // we just did the coarse pass (first iteration)
657 if (!gc_eff_set)
658 // we didn't find a feasible config so we'll just bail out; of
659 // course, it might be the case that we missed it; but I'd say
660 // it's a bit unlikely
661 done = true;
662 else {
663 // We did find a feasible config with optimal GC eff during
664 // the first pass. So the second pass we'll only consider the
665 // S-O lengths around that config with a fine increment.
667 guarantee( so_length_incr == so_coarse_increments, "invariant" );
668 guarantee( final_so_length >= min_so_length, "invariant" );
670 #ifdef TRACE_CALC_YOUNG_CONFIG
671 // leave this in for debugging, just in case
672 gclog_or_tty->print_cr(" coarse pass: SO length " SIZE_FORMAT,
673 final_so_length);
674 #endif // TRACE_CALC_YOUNG_CONFIG
676 from_so_length =
677 (final_so_length - min_so_length > so_coarse_increments) ?
678 final_so_length - so_coarse_increments + 1 : min_so_length;
679 to_so_length =
680 (max_so_length - final_so_length > so_coarse_increments) ?
681 final_so_length + so_coarse_increments - 1 : max_so_length;
683 pass = pass_type_fine;
684 so_length_incr = 1;
685 }
686 } else if (pass == pass_type_fine) {
687 // we just finished the second pass
689 if (!gc_eff_set) {
690 // we didn't find a feasible config (yes, it's possible;
691 // notice that, sometimes, we go directly into the fine
692 // iteration and skip the coarse one) so we bail out
693 done = true;
694 } else {
695 // We did find a feasible config with optimal GC eff
696 guarantee( so_length_incr == 1, "invariant" );
698 if (final_so_length == 0) {
699 // The config is of an empty S-O set, so we'll just bail out
700 done = true;
701 } else {
702 // we'll go around once more, setting the S-O length to 95%
703 // of the optimal
704 size_t new_so_length = 950 * final_so_length / 1000;
706 #ifdef TRACE_CALC_YOUNG_CONFIG
707 // leave this in for debugging, just in case
708 gclog_or_tty->print_cr(" fine pass: SO length " SIZE_FORMAT
709 ", setting it to " SIZE_FORMAT,
710 final_so_length, new_so_length);
711 #endif // TRACE_CALC_YOUNG_CONFIG
713 from_so_length = new_so_length;
714 to_so_length = new_so_length;
715 fine_so_length = final_so_length;
717 pass = pass_type_final;
718 }
719 }
720 } else if (pass == pass_type_final) {
721 // we just finished the final (third) pass
723 if (!gc_eff_set)
724 // we didn't find a feasible config, so we'll just use the one
725 // we found during the second pass, which we saved
726 final_so_length = fine_so_length;
728 // and we're done!
729 done = true;
730 } else {
731 guarantee( false, "should never reach here" );
732 }
734 // we now go around the outermost loop
735 }
737 // we should have at least one region in the target young length
738 _young_list_target_length =
739 MAX2((size_t) 1, final_young_length + _recorded_survivor_regions);
740 if (final_so_length >= final_young_length)
741 // and we need to ensure that the S-O length is not greater than
742 // the target young length (this is being a bit careful)
743 final_so_length = 0;
744 _young_list_so_prefix_length = final_so_length;
745 guarantee( !_in_marking_window || !_last_full_young_gc ||
746 _young_list_so_prefix_length == 0, "invariant" );
748 // let's keep an eye of how long we spend on this calculation
749 // right now, I assume that we'll print it when we need it; we
750 // should really adde it to the breakdown of a pause
751 double end_time_sec = os::elapsedTime();
752 double elapsed_time_ms = (end_time_sec - start_time_sec) * 1000.0;
754 #ifdef TRACE_CALC_YOUNG_CONFIG
755 // leave this in for debugging, just in case
756 gclog_or_tty->print_cr("target = %1.1lf ms, young = " SIZE_FORMAT
757 ", SO = " SIZE_FORMAT ", "
758 "elapsed %1.2lf ms, calcs: " SIZE_FORMAT " (%s%s) "
759 SIZE_FORMAT SIZE_FORMAT,
760 target_pause_time_ms,
761 _young_list_target_length - _young_list_so_prefix_length,
762 _young_list_so_prefix_length,
763 elapsed_time_ms,
764 calculations,
765 full_young_gcs() ? "full" : "partial",
766 should_initiate_conc_mark() ? " i-m" : "",
767 _in_marking_window,
768 _in_marking_window_im);
769 #endif // TRACE_CALC_YOUNG_CONFIG
771 if (_young_list_target_length < _young_list_min_length) {
772 // bummer; this means that, if we do a pause when the optimal
773 // config dictates, we'll violate the pause spacing target (the
774 // min length was calculate based on the application's current
775 // alloc rate);
777 // so, we have to bite the bullet, and allocate the minimum
778 // number. We'll violate our target, but we just can't meet it.
780 size_t so_length = 0;
781 // a note further up explains why we do not want an S-O length
782 // during marking
783 if (!_in_marking_window && !_last_full_young_gc)
784 // but we can still try to see whether we can find an optimal
785 // S-O length
786 so_length = calculate_optimal_so_length(_young_list_min_length);
788 #ifdef TRACE_CALC_YOUNG_CONFIG
789 // leave this in for debugging, just in case
790 gclog_or_tty->print_cr("adjusted target length from "
791 SIZE_FORMAT " to " SIZE_FORMAT
792 ", SO " SIZE_FORMAT,
793 _young_list_target_length, _young_list_min_length,
794 so_length);
795 #endif // TRACE_CALC_YOUNG_CONFIG
797 _young_list_target_length =
798 MAX2(_young_list_min_length, (size_t)1);
799 _young_list_so_prefix_length = so_length;
800 }
801 } else {
802 // we are in a partially-young mode or we've run out of regions (due
803 // to evacuation failure)
805 #ifdef TRACE_CALC_YOUNG_CONFIG
806 // leave this in for debugging, just in case
807 gclog_or_tty->print_cr("(partial) setting target to " SIZE_FORMAT
808 ", SO " SIZE_FORMAT,
809 _young_list_min_length, 0);
810 #endif // TRACE_CALC_YOUNG_CONFIG
812 // we'll do the pause as soon as possible and with no S-O prefix
813 // (see above for the reasons behind the latter)
814 _young_list_target_length =
815 MAX2(_young_list_min_length, (size_t) 1);
816 _young_list_so_prefix_length = 0;
817 }
819 _rs_lengths_prediction = rs_lengths;
820 }
822 // This is used by: calculate_optimal_so_length(length). It returns
823 // the GC eff and predicted pause time for a particular config
824 void
825 G1CollectorPolicy::predict_gc_eff(size_t young_length,
826 size_t so_length,
827 double base_time_ms,
828 double* ret_gc_eff,
829 double* ret_pause_time_ms) {
830 double so_time_ms = predict_scan_only_time_ms(so_length);
831 double accum_surv_rate_adj = 0.0;
832 if (so_length > 0)
833 accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
834 double accum_surv_rate =
835 accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
836 size_t bytes_to_copy =
837 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
838 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
839 double young_other_time_ms =
840 predict_young_other_time_ms(young_length - so_length);
841 double pause_time_ms =
842 base_time_ms + so_time_ms + copy_time_ms + young_other_time_ms;
843 size_t reclaimed_bytes =
844 (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
845 double gc_eff = (double) reclaimed_bytes / pause_time_ms;
847 *ret_gc_eff = gc_eff;
848 *ret_pause_time_ms = pause_time_ms;
849 }
851 // This is used by: calculate_young_list_target_config(rs_length). It
852 // returns the GC eff of a particular config. It returns false if that
853 // config violates any of the end conditions of the search in the
854 // calling method, or true upon success. The end conditions were put
855 // here since it's called twice and it was best not to replicate them
856 // in the caller. Also, passing the parameteres avoids having to
857 // recalculate them in the innermost loop.
858 bool
859 G1CollectorPolicy::predict_gc_eff(size_t young_length,
860 size_t so_length,
861 double base_time_with_so_ms,
862 size_t init_free_regions,
863 double target_pause_time_ms,
864 double* ret_gc_eff) {
865 *ret_gc_eff = 0.0;
867 if (young_length >= init_free_regions)
868 // end condition 1: not enough space for the young regions
869 return false;
871 double accum_surv_rate_adj = 0.0;
872 if (so_length > 0)
873 accum_surv_rate_adj = accum_yg_surv_rate_pred((int)(so_length - 1));
874 double accum_surv_rate =
875 accum_yg_surv_rate_pred((int)(young_length - 1)) - accum_surv_rate_adj;
876 size_t bytes_to_copy =
877 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
878 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
879 double young_other_time_ms =
880 predict_young_other_time_ms(young_length - so_length);
881 double pause_time_ms =
882 base_time_with_so_ms + copy_time_ms + young_other_time_ms;
884 if (pause_time_ms > target_pause_time_ms)
885 // end condition 2: over the target pause time
886 return false;
888 size_t reclaimed_bytes =
889 (young_length - so_length) * HeapRegion::GrainBytes - bytes_to_copy;
890 size_t free_bytes =
891 (init_free_regions - young_length) * HeapRegion::GrainBytes;
893 if ((2.0 + sigma()) * (double) bytes_to_copy > (double) free_bytes)
894 // end condition 3: out of to-space (conservatively)
895 return false;
897 // success!
898 double gc_eff = (double) reclaimed_bytes / pause_time_ms;
899 *ret_gc_eff = gc_eff;
901 return true;
902 }
904 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
905 double survivor_regions_evac_time = 0.0;
906 for (HeapRegion * r = _recorded_survivor_head;
907 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
908 r = r->get_next_young_region()) {
909 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
910 }
911 return survivor_regions_evac_time;
912 }
914 void G1CollectorPolicy::check_prediction_validity() {
915 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
917 size_t rs_lengths = _g1->young_list_sampled_rs_lengths();
918 if (rs_lengths > _rs_lengths_prediction) {
919 // add 10% to avoid having to recalculate often
920 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
921 calculate_young_list_target_config(rs_lengths_prediction);
922 }
923 }
925 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
926 bool is_tlab,
927 bool* gc_overhead_limit_was_exceeded) {
928 guarantee(false, "Not using this policy feature yet.");
929 return NULL;
930 }
932 // This method controls how a collector handles one or more
933 // of its generations being fully allocated.
934 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
935 bool is_tlab) {
936 guarantee(false, "Not using this policy feature yet.");
937 return NULL;
938 }
941 #ifndef PRODUCT
942 bool G1CollectorPolicy::verify_young_ages() {
943 HeapRegion* head = _g1->young_list_first_region();
944 return
945 verify_young_ages(head, _short_lived_surv_rate_group);
946 // also call verify_young_ages on any additional surv rate groups
947 }
949 bool
950 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
951 SurvRateGroup *surv_rate_group) {
952 guarantee( surv_rate_group != NULL, "pre-condition" );
954 const char* name = surv_rate_group->name();
955 bool ret = true;
956 int prev_age = -1;
958 for (HeapRegion* curr = head;
959 curr != NULL;
960 curr = curr->get_next_young_region()) {
961 SurvRateGroup* group = curr->surv_rate_group();
962 if (group == NULL && !curr->is_survivor()) {
963 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
964 ret = false;
965 }
967 if (surv_rate_group == group) {
968 int age = curr->age_in_surv_rate_group();
970 if (age < 0) {
971 gclog_or_tty->print_cr("## %s: encountered negative age", name);
972 ret = false;
973 }
975 if (age <= prev_age) {
976 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
977 "(%d, %d)", name, age, prev_age);
978 ret = false;
979 }
980 prev_age = age;
981 }
982 }
984 return ret;
985 }
986 #endif // PRODUCT
988 void G1CollectorPolicy::record_full_collection_start() {
989 _cur_collection_start_sec = os::elapsedTime();
990 // Release the future to-space so that it is available for compaction into.
991 _g1->set_full_collection();
992 }
994 void G1CollectorPolicy::record_full_collection_end() {
995 // Consider this like a collection pause for the purposes of allocation
996 // since last pause.
997 double end_sec = os::elapsedTime();
998 double full_gc_time_sec = end_sec - _cur_collection_start_sec;
999 double full_gc_time_ms = full_gc_time_sec * 1000.0;
1001 _all_full_gc_times_ms->add(full_gc_time_ms);
1003 update_recent_gc_times(end_sec, full_gc_time_ms);
1005 _g1->clear_full_collection();
1007 // "Nuke" the heuristics that control the fully/partially young GC
1008 // transitions and make sure we start with fully young GCs after the
1009 // Full GC.
1010 set_full_young_gcs(true);
1011 _last_full_young_gc = false;
1012 _should_revert_to_full_young_gcs = false;
1013 _should_initiate_conc_mark = false;
1014 _known_garbage_bytes = 0;
1015 _known_garbage_ratio = 0.0;
1016 _in_marking_window = false;
1017 _in_marking_window_im = false;
1019 _short_lived_surv_rate_group->record_scan_only_prefix(0);
1020 _short_lived_surv_rate_group->start_adding_regions();
1021 // also call this on any additional surv rate groups
1023 record_survivor_regions(0, NULL, NULL);
1025 _prev_region_num_young = _region_num_young;
1026 _prev_region_num_tenured = _region_num_tenured;
1028 _free_regions_at_end_of_collection = _g1->free_regions();
1029 _scan_only_regions_at_end_of_collection = 0;
1030 // Reset survivors SurvRateGroup.
1031 _survivor_surv_rate_group->reset();
1032 calculate_young_list_min_length();
1033 calculate_young_list_target_config();
1034 }
1036 void G1CollectorPolicy::record_before_bytes(size_t bytes) {
1037 _bytes_in_to_space_before_gc += bytes;
1038 }
1040 void G1CollectorPolicy::record_after_bytes(size_t bytes) {
1041 _bytes_in_to_space_after_gc += bytes;
1042 }
1044 void G1CollectorPolicy::record_stop_world_start() {
1045 _stop_world_start = os::elapsedTime();
1046 }
1048 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
1049 size_t start_used) {
1050 if (PrintGCDetails) {
1051 gclog_or_tty->stamp(PrintGCTimeStamps);
1052 gclog_or_tty->print("[GC pause");
1053 if (in_young_gc_mode())
1054 gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
1055 }
1057 assert(_g1->used_regions() == _g1->recalculate_used_regions(),
1058 "sanity");
1059 assert(_g1->used() == _g1->recalculate_used(), "sanity");
1061 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
1062 _all_stop_world_times_ms->add(s_w_t_ms);
1063 _stop_world_start = 0.0;
1065 _cur_collection_start_sec = start_time_sec;
1066 _cur_collection_pause_used_at_start_bytes = start_used;
1067 _cur_collection_pause_used_regions_at_start = _g1->used_regions();
1068 _pending_cards = _g1->pending_card_num();
1069 _max_pending_cards = _g1->max_pending_card_num();
1071 _bytes_in_to_space_before_gc = 0;
1072 _bytes_in_to_space_after_gc = 0;
1073 _bytes_in_collection_set_before_gc = 0;
1075 #ifdef DEBUG
1076 // initialise these to something well known so that we can spot
1077 // if they are not set properly
1079 for (int i = 0; i < _parallel_gc_threads; ++i) {
1080 _par_last_ext_root_scan_times_ms[i] = -666.0;
1081 _par_last_mark_stack_scan_times_ms[i] = -666.0;
1082 _par_last_scan_only_times_ms[i] = -666.0;
1083 _par_last_scan_only_regions_scanned[i] = -666.0;
1084 _par_last_update_rs_start_times_ms[i] = -666.0;
1085 _par_last_update_rs_times_ms[i] = -666.0;
1086 _par_last_update_rs_processed_buffers[i] = -666.0;
1087 _par_last_scan_rs_start_times_ms[i] = -666.0;
1088 _par_last_scan_rs_times_ms[i] = -666.0;
1089 _par_last_scan_new_refs_times_ms[i] = -666.0;
1090 _par_last_obj_copy_times_ms[i] = -666.0;
1091 _par_last_termination_times_ms[i] = -666.0;
1092 }
1093 #endif
1095 for (int i = 0; i < _aux_num; ++i) {
1096 _cur_aux_times_ms[i] = 0.0;
1097 _cur_aux_times_set[i] = false;
1098 }
1100 _satb_drain_time_set = false;
1101 _last_satb_drain_processed_buffers = -1;
1103 if (in_young_gc_mode())
1104 _last_young_gc_full = false;
1107 // do that for any other surv rate groups
1108 _short_lived_surv_rate_group->stop_adding_regions();
1109 size_t short_lived_so_length = _young_list_so_prefix_length;
1110 _short_lived_surv_rate_group->record_scan_only_prefix(short_lived_so_length);
1111 tag_scan_only(short_lived_so_length);
1113 if (G1UseSurvivorSpaces) {
1114 _survivors_age_table.clear();
1115 }
1117 assert( verify_young_ages(), "region age verification" );
1118 }
1120 void G1CollectorPolicy::tag_scan_only(size_t short_lived_scan_only_length) {
1121 // done in a way that it can be extended for other surv rate groups too...
1123 HeapRegion* head = _g1->young_list_first_region();
1124 bool finished_short_lived = (short_lived_scan_only_length == 0);
1126 if (finished_short_lived)
1127 return;
1129 for (HeapRegion* curr = head;
1130 curr != NULL;
1131 curr = curr->get_next_young_region()) {
1132 SurvRateGroup* surv_rate_group = curr->surv_rate_group();
1133 int age = curr->age_in_surv_rate_group();
1135 if (surv_rate_group == _short_lived_surv_rate_group) {
1136 if ((size_t)age < short_lived_scan_only_length)
1137 curr->set_scan_only();
1138 else
1139 finished_short_lived = true;
1140 }
1143 if (finished_short_lived)
1144 return;
1145 }
1147 guarantee( false, "we should never reach here" );
1148 }
1150 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
1151 _mark_closure_time_ms = mark_closure_time_ms;
1152 }
1154 void G1CollectorPolicy::record_concurrent_mark_init_start() {
1155 _mark_init_start_sec = os::elapsedTime();
1156 guarantee(!in_young_gc_mode(), "should not do be here in young GC mode");
1157 }
1159 void G1CollectorPolicy::record_concurrent_mark_init_end_pre(double
1160 mark_init_elapsed_time_ms) {
1161 _during_marking = true;
1162 _should_initiate_conc_mark = false;
1163 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
1164 }
1166 void G1CollectorPolicy::record_concurrent_mark_init_end() {
1167 double end_time_sec = os::elapsedTime();
1168 double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
1169 _concurrent_mark_init_times_ms->add(elapsed_time_ms);
1170 record_concurrent_mark_init_end_pre(elapsed_time_ms);
1172 _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true);
1173 }
1175 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
1176 _mark_remark_start_sec = os::elapsedTime();
1177 _during_marking = false;
1178 }
1180 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
1181 double end_time_sec = os::elapsedTime();
1182 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
1183 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
1184 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1185 _prev_collection_pause_end_ms += elapsed_time_ms;
1187 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
1188 }
1190 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
1191 _mark_cleanup_start_sec = os::elapsedTime();
1192 }
1194 void
1195 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
1196 size_t max_live_bytes) {
1197 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
1198 record_concurrent_mark_cleanup_end_work2();
1199 }
1201 void
1202 G1CollectorPolicy::
1203 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
1204 size_t max_live_bytes) {
1205 if (_n_marks < 2) _n_marks++;
1206 if (G1PolicyVerbose > 0)
1207 gclog_or_tty->print_cr("At end of marking, max_live is " SIZE_FORMAT " MB "
1208 " (of " SIZE_FORMAT " MB heap).",
1209 max_live_bytes/M, _g1->capacity()/M);
1210 }
1212 // The important thing about this is that it includes "os::elapsedTime".
1213 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
1214 double end_time_sec = os::elapsedTime();
1215 double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
1216 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1217 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1218 _prev_collection_pause_end_ms += elapsed_time_ms;
1220 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
1222 _num_markings++;
1224 // We did a marking, so reset the "since_last_mark" variables.
1225 double considerConcMarkCost = 1.0;
1226 // If there are available processors, concurrent activity is free...
1227 if (Threads::number_of_non_daemon_threads() * 2 <
1228 os::active_processor_count()) {
1229 considerConcMarkCost = 0.0;
1230 }
1231 _n_pauses_at_mark_end = _n_pauses;
1232 _n_marks_since_last_pause++;
1233 _conc_mark_initiated = false;
1234 }
1236 void
1237 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
1238 if (in_young_gc_mode()) {
1239 _should_revert_to_full_young_gcs = false;
1240 _last_full_young_gc = true;
1241 _in_marking_window = false;
1242 if (adaptive_young_list_length())
1243 calculate_young_list_target_config();
1244 }
1245 }
1247 void G1CollectorPolicy::record_concurrent_pause() {
1248 if (_stop_world_start > 0.0) {
1249 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
1250 _all_yield_times_ms->add(yield_ms);
1251 }
1252 }
1254 void G1CollectorPolicy::record_concurrent_pause_end() {
1255 }
1257 void G1CollectorPolicy::record_collection_pause_end_CH_strong_roots() {
1258 _cur_CH_strong_roots_end_sec = os::elapsedTime();
1259 _cur_CH_strong_roots_dur_ms =
1260 (_cur_CH_strong_roots_end_sec - _cur_collection_start_sec) * 1000.0;
1261 }
1263 void G1CollectorPolicy::record_collection_pause_end_G1_strong_roots() {
1264 _cur_G1_strong_roots_end_sec = os::elapsedTime();
1265 _cur_G1_strong_roots_dur_ms =
1266 (_cur_G1_strong_roots_end_sec - _cur_CH_strong_roots_end_sec) * 1000.0;
1267 }
1269 template<class T>
1270 T sum_of(T* sum_arr, int start, int n, int N) {
1271 T sum = (T)0;
1272 for (int i = 0; i < n; i++) {
1273 int j = (start + i) % N;
1274 sum += sum_arr[j];
1275 }
1276 return sum;
1277 }
1279 void G1CollectorPolicy::print_par_stats (int level,
1280 const char* str,
1281 double* data,
1282 bool summary) {
1283 double min = data[0], max = data[0];
1284 double total = 0.0;
1285 int j;
1286 for (j = 0; j < level; ++j)
1287 gclog_or_tty->print(" ");
1288 gclog_or_tty->print("[%s (ms):", str);
1289 for (uint i = 0; i < ParallelGCThreads; ++i) {
1290 double val = data[i];
1291 if (val < min)
1292 min = val;
1293 if (val > max)
1294 max = val;
1295 total += val;
1296 gclog_or_tty->print(" %3.1lf", val);
1297 }
1298 if (summary) {
1299 gclog_or_tty->print_cr("");
1300 double avg = total / (double) ParallelGCThreads;
1301 gclog_or_tty->print(" ");
1302 for (j = 0; j < level; ++j)
1303 gclog_or_tty->print(" ");
1304 gclog_or_tty->print("Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf",
1305 avg, min, max);
1306 }
1307 gclog_or_tty->print_cr("]");
1308 }
1310 void G1CollectorPolicy::print_par_buffers (int level,
1311 const char* str,
1312 double* data,
1313 bool summary) {
1314 double min = data[0], max = data[0];
1315 double total = 0.0;
1316 int j;
1317 for (j = 0; j < level; ++j)
1318 gclog_or_tty->print(" ");
1319 gclog_or_tty->print("[%s :", str);
1320 for (uint i = 0; i < ParallelGCThreads; ++i) {
1321 double val = data[i];
1322 if (val < min)
1323 min = val;
1324 if (val > max)
1325 max = val;
1326 total += val;
1327 gclog_or_tty->print(" %d", (int) val);
1328 }
1329 if (summary) {
1330 gclog_or_tty->print_cr("");
1331 double avg = total / (double) ParallelGCThreads;
1332 gclog_or_tty->print(" ");
1333 for (j = 0; j < level; ++j)
1334 gclog_or_tty->print(" ");
1335 gclog_or_tty->print("Sum: %d, Avg: %d, Min: %d, Max: %d",
1336 (int)total, (int)avg, (int)min, (int)max);
1337 }
1338 gclog_or_tty->print_cr("]");
1339 }
1341 void G1CollectorPolicy::print_stats (int level,
1342 const char* str,
1343 double value) {
1344 for (int j = 0; j < level; ++j)
1345 gclog_or_tty->print(" ");
1346 gclog_or_tty->print_cr("[%s: %5.1lf ms]", str, value);
1347 }
1349 void G1CollectorPolicy::print_stats (int level,
1350 const char* str,
1351 int value) {
1352 for (int j = 0; j < level; ++j)
1353 gclog_or_tty->print(" ");
1354 gclog_or_tty->print_cr("[%s: %d]", str, value);
1355 }
1357 double G1CollectorPolicy::avg_value (double* data) {
1358 if (ParallelGCThreads > 0) {
1359 double ret = 0.0;
1360 for (uint i = 0; i < ParallelGCThreads; ++i)
1361 ret += data[i];
1362 return ret / (double) ParallelGCThreads;
1363 } else {
1364 return data[0];
1365 }
1366 }
1368 double G1CollectorPolicy::max_value (double* data) {
1369 if (ParallelGCThreads > 0) {
1370 double ret = data[0];
1371 for (uint i = 1; i < ParallelGCThreads; ++i)
1372 if (data[i] > ret)
1373 ret = data[i];
1374 return ret;
1375 } else {
1376 return data[0];
1377 }
1378 }
1380 double G1CollectorPolicy::sum_of_values (double* data) {
1381 if (ParallelGCThreads > 0) {
1382 double sum = 0.0;
1383 for (uint i = 0; i < ParallelGCThreads; i++)
1384 sum += data[i];
1385 return sum;
1386 } else {
1387 return data[0];
1388 }
1389 }
1391 double G1CollectorPolicy::max_sum (double* data1,
1392 double* data2) {
1393 double ret = data1[0] + data2[0];
1395 if (ParallelGCThreads > 0) {
1396 for (uint i = 1; i < ParallelGCThreads; ++i) {
1397 double data = data1[i] + data2[i];
1398 if (data > ret)
1399 ret = data;
1400 }
1401 }
1402 return ret;
1403 }
1405 // Anything below that is considered to be zero
1406 #define MIN_TIMER_GRANULARITY 0.0000001
1408 void G1CollectorPolicy::record_collection_pause_end(bool abandoned) {
1409 double end_time_sec = os::elapsedTime();
1410 double elapsed_ms = _last_pause_time_ms;
1411 bool parallel = ParallelGCThreads > 0;
1412 double evac_ms = (end_time_sec - _cur_G1_strong_roots_end_sec) * 1000.0;
1413 size_t rs_size =
1414 _cur_collection_pause_used_regions_at_start - collection_set_size();
1415 size_t cur_used_bytes = _g1->used();
1416 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1417 bool last_pause_included_initial_mark = false;
1418 bool update_stats = !abandoned && !_g1->evacuation_failed();
1420 #ifndef PRODUCT
1421 if (G1YoungSurvRateVerbose) {
1422 gclog_or_tty->print_cr("");
1423 _short_lived_surv_rate_group->print();
1424 // do that for any other surv rate groups too
1425 }
1426 #endif // PRODUCT
1428 if (in_young_gc_mode()) {
1429 last_pause_included_initial_mark = _should_initiate_conc_mark;
1430 if (last_pause_included_initial_mark)
1431 record_concurrent_mark_init_end_pre(0.0);
1433 size_t min_used_targ =
1434 (_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta);
1436 if (cur_used_bytes > min_used_targ) {
1437 if (cur_used_bytes <= _prev_collection_pause_used_at_end_bytes) {
1438 } else if (!_g1->mark_in_progress() && !_last_full_young_gc) {
1439 _should_initiate_conc_mark = true;
1440 }
1441 }
1443 _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
1444 }
1446 _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
1447 end_time_sec, false);
1449 guarantee(_cur_collection_pause_used_regions_at_start >=
1450 collection_set_size(),
1451 "Negative RS size?");
1453 // This assert is exempted when we're doing parallel collection pauses,
1454 // because the fragmentation caused by the parallel GC allocation buffers
1455 // can lead to more memory being used during collection than was used
1456 // before. Best leave this out until the fragmentation problem is fixed.
1457 // Pauses in which evacuation failed can also lead to negative
1458 // collections, since no space is reclaimed from a region containing an
1459 // object whose evacuation failed.
1460 // Further, we're now always doing parallel collection. But I'm still
1461 // leaving this here as a placeholder for a more precise assertion later.
1462 // (DLD, 10/05.)
1463 assert((true || parallel) // Always using GC LABs now.
1464 || _g1->evacuation_failed()
1465 || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
1466 "Negative collection");
1468 size_t freed_bytes =
1469 _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
1470 size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
1471 double survival_fraction =
1472 (double)surviving_bytes/
1473 (double)_collection_set_bytes_used_before;
1475 _n_pauses++;
1477 if (update_stats) {
1478 _recent_CH_strong_roots_times_ms->add(_cur_CH_strong_roots_dur_ms);
1479 _recent_G1_strong_roots_times_ms->add(_cur_G1_strong_roots_dur_ms);
1480 _recent_evac_times_ms->add(evac_ms);
1481 _recent_pause_times_ms->add(elapsed_ms);
1483 _recent_rs_sizes->add(rs_size);
1485 // We exempt parallel collection from this check because Alloc Buffer
1486 // fragmentation can produce negative collections. Same with evac
1487 // failure.
1488 // Further, we're now always doing parallel collection. But I'm still
1489 // leaving this here as a placeholder for a more precise assertion later.
1490 // (DLD, 10/05.
1491 assert((true || parallel)
1492 || _g1->evacuation_failed()
1493 || surviving_bytes <= _collection_set_bytes_used_before,
1494 "Or else negative collection!");
1495 _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
1496 _recent_CS_bytes_surviving->add(surviving_bytes);
1498 // this is where we update the allocation rate of the application
1499 double app_time_ms =
1500 (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
1501 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1502 // This usually happens due to the timer not having the required
1503 // granularity. Some Linuxes are the usual culprits.
1504 // We'll just set it to something (arbitrarily) small.
1505 app_time_ms = 1.0;
1506 }
1507 size_t regions_allocated =
1508 (_region_num_young - _prev_region_num_young) +
1509 (_region_num_tenured - _prev_region_num_tenured);
1510 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1511 _alloc_rate_ms_seq->add(alloc_rate_ms);
1512 _prev_region_num_young = _region_num_young;
1513 _prev_region_num_tenured = _region_num_tenured;
1515 double interval_ms =
1516 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1517 update_recent_gc_times(end_time_sec, elapsed_ms);
1518 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1519 if (recent_avg_pause_time_ratio() < 0.0 ||
1520 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1521 #ifndef PRODUCT
1522 // Dump info to allow post-facto debugging
1523 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1524 gclog_or_tty->print_cr("-------------------------------------------");
1525 gclog_or_tty->print_cr("Recent GC Times (ms):");
1526 _recent_gc_times_ms->dump();
1527 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1528 _recent_prev_end_times_for_all_gcs_sec->dump();
1529 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1530 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1531 // In debug mode, terminate the JVM if the user wants to debug at this point.
1532 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1533 #endif // !PRODUCT
1534 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1535 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1536 if (_recent_avg_pause_time_ratio < 0.0) {
1537 _recent_avg_pause_time_ratio = 0.0;
1538 } else {
1539 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1540 _recent_avg_pause_time_ratio = 1.0;
1541 }
1542 }
1543 }
1545 if (G1PolicyVerbose > 1) {
1546 gclog_or_tty->print_cr(" Recording collection pause(%d)", _n_pauses);
1547 }
1549 PauseSummary* summary;
1550 if (abandoned) {
1551 summary = _abandoned_summary;
1552 } else {
1553 summary = _summary;
1554 }
1556 double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
1557 double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
1558 double scan_only_time = avg_value(_par_last_scan_only_times_ms);
1559 double scan_only_regions_scanned =
1560 sum_of_values(_par_last_scan_only_regions_scanned);
1561 double update_rs_time = avg_value(_par_last_update_rs_times_ms);
1562 double update_rs_processed_buffers =
1563 sum_of_values(_par_last_update_rs_processed_buffers);
1564 double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
1565 double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
1566 double termination_time = avg_value(_par_last_termination_times_ms);
1568 double parallel_other_time = _cur_collection_par_time_ms -
1569 (update_rs_time + ext_root_scan_time + mark_stack_scan_time +
1570 scan_only_time + scan_rs_time + obj_copy_time + termination_time);
1571 if (update_stats) {
1572 MainBodySummary* body_summary = summary->main_body_summary();
1573 guarantee(body_summary != NULL, "should not be null!");
1575 if (_satb_drain_time_set)
1576 body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
1577 else
1578 body_summary->record_satb_drain_time_ms(0.0);
1579 body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
1580 body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
1581 body_summary->record_scan_only_time_ms(scan_only_time);
1582 body_summary->record_update_rs_time_ms(update_rs_time);
1583 body_summary->record_scan_rs_time_ms(scan_rs_time);
1584 body_summary->record_obj_copy_time_ms(obj_copy_time);
1585 if (parallel) {
1586 body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
1587 body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
1588 body_summary->record_termination_time_ms(termination_time);
1589 body_summary->record_parallel_other_time_ms(parallel_other_time);
1590 }
1591 body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
1592 }
1594 if (G1PolicyVerbose > 1) {
1595 gclog_or_tty->print_cr(" ET: %10.6f ms (avg: %10.6f ms)\n"
1596 " CH Strong: %10.6f ms (avg: %10.6f ms)\n"
1597 " G1 Strong: %10.6f ms (avg: %10.6f ms)\n"
1598 " Evac: %10.6f ms (avg: %10.6f ms)\n"
1599 " ET-RS: %10.6f ms (avg: %10.6f ms)\n"
1600 " |RS|: " SIZE_FORMAT,
1601 elapsed_ms, recent_avg_time_for_pauses_ms(),
1602 _cur_CH_strong_roots_dur_ms, recent_avg_time_for_CH_strong_ms(),
1603 _cur_G1_strong_roots_dur_ms, recent_avg_time_for_G1_strong_ms(),
1604 evac_ms, recent_avg_time_for_evac_ms(),
1605 scan_rs_time,
1606 recent_avg_time_for_pauses_ms() -
1607 recent_avg_time_for_G1_strong_ms(),
1608 rs_size);
1610 gclog_or_tty->print_cr(" Used at start: " SIZE_FORMAT"K"
1611 " At end " SIZE_FORMAT "K\n"
1612 " garbage : " SIZE_FORMAT "K"
1613 " of " SIZE_FORMAT "K\n"
1614 " survival : %6.2f%% (%6.2f%% avg)",
1615 _cur_collection_pause_used_at_start_bytes/K,
1616 _g1->used()/K, freed_bytes/K,
1617 _collection_set_bytes_used_before/K,
1618 survival_fraction*100.0,
1619 recent_avg_survival_fraction()*100.0);
1620 gclog_or_tty->print_cr(" Recent %% gc pause time: %6.2f",
1621 recent_avg_pause_time_ratio() * 100.0);
1622 }
1624 double other_time_ms = elapsed_ms;
1626 if (!abandoned) {
1627 if (_satb_drain_time_set)
1628 other_time_ms -= _cur_satb_drain_time_ms;
1630 if (parallel)
1631 other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
1632 else
1633 other_time_ms -=
1634 update_rs_time +
1635 ext_root_scan_time + mark_stack_scan_time + scan_only_time +
1636 scan_rs_time + obj_copy_time;
1637 }
1639 if (PrintGCDetails) {
1640 gclog_or_tty->print_cr("%s%s, %1.8lf secs]",
1641 abandoned ? " (abandoned)" : "",
1642 (last_pause_included_initial_mark) ? " (initial-mark)" : "",
1643 elapsed_ms / 1000.0);
1645 if (!abandoned) {
1646 if (_satb_drain_time_set) {
1647 print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
1648 }
1649 if (_last_satb_drain_processed_buffers >= 0) {
1650 print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
1651 }
1652 if (parallel) {
1653 print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
1654 print_par_stats(2, "Update RS (Start)", _par_last_update_rs_start_times_ms, false);
1655 print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
1656 print_par_buffers(3, "Processed Buffers",
1657 _par_last_update_rs_processed_buffers, true);
1658 print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
1659 print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
1660 print_par_stats(2, "Scan-Only Scanning", _par_last_scan_only_times_ms);
1661 print_par_buffers(3, "Scan-Only Regions",
1662 _par_last_scan_only_regions_scanned, true);
1663 print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
1664 print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
1665 print_par_stats(2, "Termination", _par_last_termination_times_ms);
1666 print_stats(2, "Other", parallel_other_time);
1667 print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
1668 } else {
1669 print_stats(1, "Update RS", update_rs_time);
1670 print_stats(2, "Processed Buffers",
1671 (int)update_rs_processed_buffers);
1672 print_stats(1, "Ext Root Scanning", ext_root_scan_time);
1673 print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
1674 print_stats(1, "Scan-Only Scanning", scan_only_time);
1675 print_stats(1, "Scan RS", scan_rs_time);
1676 print_stats(1, "Object Copying", obj_copy_time);
1677 }
1678 }
1679 #ifndef PRODUCT
1680 print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
1681 print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
1682 print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
1683 print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
1684 if (_num_cc_clears > 0) {
1685 print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
1686 }
1687 #endif
1688 print_stats(1, "Other", other_time_ms);
1689 for (int i = 0; i < _aux_num; ++i) {
1690 if (_cur_aux_times_set[i]) {
1691 char buffer[96];
1692 sprintf(buffer, "Aux%d", i);
1693 print_stats(1, buffer, _cur_aux_times_ms[i]);
1694 }
1695 }
1696 }
1697 if (PrintGCDetails)
1698 gclog_or_tty->print(" [");
1699 if (PrintGC || PrintGCDetails)
1700 _g1->print_size_transition(gclog_or_tty,
1701 _cur_collection_pause_used_at_start_bytes,
1702 _g1->used(), _g1->capacity());
1703 if (PrintGCDetails)
1704 gclog_or_tty->print_cr("]");
1706 _all_pause_times_ms->add(elapsed_ms);
1707 if (update_stats) {
1708 summary->record_total_time_ms(elapsed_ms);
1709 summary->record_other_time_ms(other_time_ms);
1710 }
1711 for (int i = 0; i < _aux_num; ++i)
1712 if (_cur_aux_times_set[i])
1713 _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
1715 // Reset marks-between-pauses counter.
1716 _n_marks_since_last_pause = 0;
1718 // Update the efficiency-since-mark vars.
1719 double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
1720 if (elapsed_ms < MIN_TIMER_GRANULARITY) {
1721 // This usually happens due to the timer not having the required
1722 // granularity. Some Linuxes are the usual culprits.
1723 // We'll just set it to something (arbitrarily) small.
1724 proc_ms = 1.0;
1725 }
1726 double cur_efficiency = (double) freed_bytes / proc_ms;
1728 bool new_in_marking_window = _in_marking_window;
1729 bool new_in_marking_window_im = false;
1730 if (_should_initiate_conc_mark) {
1731 new_in_marking_window = true;
1732 new_in_marking_window_im = true;
1733 }
1735 if (in_young_gc_mode()) {
1736 if (_last_full_young_gc) {
1737 set_full_young_gcs(false);
1738 _last_full_young_gc = false;
1739 }
1741 if ( !_last_young_gc_full ) {
1742 if ( _should_revert_to_full_young_gcs ||
1743 _known_garbage_ratio < 0.05 ||
1744 (adaptive_young_list_length() &&
1745 (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) ) {
1746 set_full_young_gcs(true);
1747 }
1748 }
1749 _should_revert_to_full_young_gcs = false;
1751 if (_last_young_gc_full && !_during_marking)
1752 _young_gc_eff_seq->add(cur_efficiency);
1753 }
1755 _short_lived_surv_rate_group->start_adding_regions();
1756 // do that for any other surv rate groupsx
1758 // <NEW PREDICTION>
1760 if (update_stats) {
1761 double pause_time_ms = elapsed_ms;
1763 size_t diff = 0;
1764 if (_max_pending_cards >= _pending_cards)
1765 diff = _max_pending_cards - _pending_cards;
1766 _pending_card_diff_seq->add((double) diff);
1768 double cost_per_card_ms = 0.0;
1769 if (_pending_cards > 0) {
1770 cost_per_card_ms = update_rs_time / (double) _pending_cards;
1771 _cost_per_card_ms_seq->add(cost_per_card_ms);
1772 }
1774 double cost_per_scan_only_region_ms = 0.0;
1775 if (scan_only_regions_scanned > 0.0) {
1776 cost_per_scan_only_region_ms =
1777 scan_only_time / scan_only_regions_scanned;
1778 if (_in_marking_window_im)
1779 _cost_per_scan_only_region_ms_during_cm_seq->add(cost_per_scan_only_region_ms);
1780 else
1781 _cost_per_scan_only_region_ms_seq->add(cost_per_scan_only_region_ms);
1782 }
1784 size_t cards_scanned = _g1->cards_scanned();
1786 double cost_per_entry_ms = 0.0;
1787 if (cards_scanned > 10) {
1788 cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
1789 if (_last_young_gc_full)
1790 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1791 else
1792 _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1793 }
1795 if (_max_rs_lengths > 0) {
1796 double cards_per_entry_ratio =
1797 (double) cards_scanned / (double) _max_rs_lengths;
1798 if (_last_young_gc_full)
1799 _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1800 else
1801 _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1802 }
1804 size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1805 if (rs_length_diff >= 0)
1806 _rs_length_diff_seq->add((double) rs_length_diff);
1808 size_t copied_bytes = surviving_bytes;
1809 double cost_per_byte_ms = 0.0;
1810 if (copied_bytes > 0) {
1811 cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
1812 if (_in_marking_window)
1813 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1814 else
1815 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1816 }
1818 double all_other_time_ms = pause_time_ms -
1819 (update_rs_time + scan_only_time + scan_rs_time + obj_copy_time +
1820 _mark_closure_time_ms + termination_time);
1822 double young_other_time_ms = 0.0;
1823 if (_recorded_young_regions > 0) {
1824 young_other_time_ms =
1825 _recorded_young_cset_choice_time_ms +
1826 _recorded_young_free_cset_time_ms;
1827 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1828 (double) _recorded_young_regions);
1829 }
1830 double non_young_other_time_ms = 0.0;
1831 if (_recorded_non_young_regions > 0) {
1832 non_young_other_time_ms =
1833 _recorded_non_young_cset_choice_time_ms +
1834 _recorded_non_young_free_cset_time_ms;
1836 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1837 (double) _recorded_non_young_regions);
1838 }
1840 double constant_other_time_ms = all_other_time_ms -
1841 (young_other_time_ms + non_young_other_time_ms);
1842 _constant_other_time_ms_seq->add(constant_other_time_ms);
1844 double survival_ratio = 0.0;
1845 if (_bytes_in_collection_set_before_gc > 0) {
1846 survival_ratio = (double) bytes_in_to_space_during_gc() /
1847 (double) _bytes_in_collection_set_before_gc;
1848 }
1850 _pending_cards_seq->add((double) _pending_cards);
1851 _scanned_cards_seq->add((double) cards_scanned);
1852 _rs_lengths_seq->add((double) _max_rs_lengths);
1854 double expensive_region_limit_ms =
1855 (double) MaxGCPauseMillis - predict_constant_other_time_ms();
1856 if (expensive_region_limit_ms < 0.0) {
1857 // this means that the other time was predicted to be longer than
1858 // than the max pause time
1859 expensive_region_limit_ms = (double) MaxGCPauseMillis;
1860 }
1861 _expensive_region_limit_ms = expensive_region_limit_ms;
1863 if (PREDICTIONS_VERBOSE) {
1864 gclog_or_tty->print_cr("");
1865 gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
1866 "REGIONS %d %d %d %d "
1867 "PENDING_CARDS %d %d "
1868 "CARDS_SCANNED %d %d "
1869 "RS_LENGTHS %d %d "
1870 "SCAN_ONLY_SCAN %1.6lf %1.6lf "
1871 "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
1872 "SURVIVAL_RATIO %1.6lf %1.6lf "
1873 "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
1874 "OTHER_YOUNG %1.6lf %1.6lf "
1875 "OTHER_NON_YOUNG %1.6lf %1.6lf "
1876 "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
1877 "ELAPSED %1.6lf %1.6lf ",
1878 _cur_collection_start_sec,
1879 (!_last_young_gc_full) ? 2 :
1880 (last_pause_included_initial_mark) ? 1 : 0,
1881 _recorded_region_num,
1882 _recorded_young_regions,
1883 _recorded_scan_only_regions,
1884 _recorded_non_young_regions,
1885 _predicted_pending_cards, _pending_cards,
1886 _predicted_cards_scanned, cards_scanned,
1887 _predicted_rs_lengths, _max_rs_lengths,
1888 _predicted_scan_only_scan_time_ms, scan_only_time,
1889 _predicted_rs_update_time_ms, update_rs_time,
1890 _predicted_rs_scan_time_ms, scan_rs_time,
1891 _predicted_survival_ratio, survival_ratio,
1892 _predicted_object_copy_time_ms, obj_copy_time,
1893 _predicted_constant_other_time_ms, constant_other_time_ms,
1894 _predicted_young_other_time_ms, young_other_time_ms,
1895 _predicted_non_young_other_time_ms,
1896 non_young_other_time_ms,
1897 _vtime_diff_ms, termination_time,
1898 _predicted_pause_time_ms, elapsed_ms);
1899 }
1901 if (G1PolicyVerbose > 0) {
1902 gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
1903 _predicted_pause_time_ms,
1904 (_within_target) ? "within" : "outside",
1905 elapsed_ms);
1906 }
1908 }
1910 _in_marking_window = new_in_marking_window;
1911 _in_marking_window_im = new_in_marking_window_im;
1912 _free_regions_at_end_of_collection = _g1->free_regions();
1913 _scan_only_regions_at_end_of_collection = _g1->young_list_length();
1914 calculate_young_list_min_length();
1915 calculate_young_list_target_config();
1917 // </NEW PREDICTION>
1919 _target_pause_time_ms = -1.0;
1920 }
1922 // <NEW PREDICTION>
1924 double
1925 G1CollectorPolicy::
1926 predict_young_collection_elapsed_time_ms(size_t adjustment) {
1927 guarantee( adjustment == 0 || adjustment == 1, "invariant" );
1929 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1930 size_t young_num = g1h->young_list_length();
1931 if (young_num == 0)
1932 return 0.0;
1934 young_num += adjustment;
1935 size_t pending_cards = predict_pending_cards();
1936 size_t rs_lengths = g1h->young_list_sampled_rs_lengths() +
1937 predict_rs_length_diff();
1938 size_t card_num;
1939 if (full_young_gcs())
1940 card_num = predict_young_card_num(rs_lengths);
1941 else
1942 card_num = predict_non_young_card_num(rs_lengths);
1943 size_t young_byte_size = young_num * HeapRegion::GrainBytes;
1944 double accum_yg_surv_rate =
1945 _short_lived_surv_rate_group->accum_surv_rate(adjustment);
1947 size_t bytes_to_copy =
1948 (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
1950 return
1951 predict_rs_update_time_ms(pending_cards) +
1952 predict_rs_scan_time_ms(card_num) +
1953 predict_object_copy_time_ms(bytes_to_copy) +
1954 predict_young_other_time_ms(young_num) +
1955 predict_constant_other_time_ms();
1956 }
1958 double
1959 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1960 size_t rs_length = predict_rs_length_diff();
1961 size_t card_num;
1962 if (full_young_gcs())
1963 card_num = predict_young_card_num(rs_length);
1964 else
1965 card_num = predict_non_young_card_num(rs_length);
1966 return predict_base_elapsed_time_ms(pending_cards, card_num);
1967 }
1969 double
1970 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1971 size_t scanned_cards) {
1972 return
1973 predict_rs_update_time_ms(pending_cards) +
1974 predict_rs_scan_time_ms(scanned_cards) +
1975 predict_constant_other_time_ms();
1976 }
1978 double
1979 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1980 bool young) {
1981 size_t rs_length = hr->rem_set()->occupied();
1982 size_t card_num;
1983 if (full_young_gcs())
1984 card_num = predict_young_card_num(rs_length);
1985 else
1986 card_num = predict_non_young_card_num(rs_length);
1987 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1989 double region_elapsed_time_ms =
1990 predict_rs_scan_time_ms(card_num) +
1991 predict_object_copy_time_ms(bytes_to_copy);
1993 if (young)
1994 region_elapsed_time_ms += predict_young_other_time_ms(1);
1995 else
1996 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1998 return region_elapsed_time_ms;
1999 }
2001 size_t
2002 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
2003 size_t bytes_to_copy;
2004 if (hr->is_marked())
2005 bytes_to_copy = hr->max_live_bytes();
2006 else {
2007 guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
2008 "invariant" );
2009 int age = hr->age_in_surv_rate_group();
2010 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
2011 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
2012 }
2014 return bytes_to_copy;
2015 }
2017 void
2018 G1CollectorPolicy::start_recording_regions() {
2019 _recorded_rs_lengths = 0;
2020 _recorded_scan_only_regions = 0;
2021 _recorded_young_regions = 0;
2022 _recorded_non_young_regions = 0;
2024 #if PREDICTIONS_VERBOSE
2025 _predicted_rs_lengths = 0;
2026 _predicted_cards_scanned = 0;
2028 _recorded_marked_bytes = 0;
2029 _recorded_young_bytes = 0;
2030 _predicted_bytes_to_copy = 0;
2031 #endif // PREDICTIONS_VERBOSE
2032 }
2034 void
2035 G1CollectorPolicy::record_cset_region(HeapRegion* hr, bool young) {
2036 if (young) {
2037 ++_recorded_young_regions;
2038 } else {
2039 ++_recorded_non_young_regions;
2040 }
2041 #if PREDICTIONS_VERBOSE
2042 if (young) {
2043 _recorded_young_bytes += hr->used();
2044 } else {
2045 _recorded_marked_bytes += hr->max_live_bytes();
2046 }
2047 _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
2048 #endif // PREDICTIONS_VERBOSE
2050 size_t rs_length = hr->rem_set()->occupied();
2051 _recorded_rs_lengths += rs_length;
2052 }
2054 void
2055 G1CollectorPolicy::record_scan_only_regions(size_t scan_only_length) {
2056 _recorded_scan_only_regions = scan_only_length;
2057 }
2059 void
2060 G1CollectorPolicy::end_recording_regions() {
2061 #if PREDICTIONS_VERBOSE
2062 _predicted_pending_cards = predict_pending_cards();
2063 _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
2064 if (full_young_gcs())
2065 _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
2066 else
2067 _predicted_cards_scanned +=
2068 predict_non_young_card_num(_predicted_rs_lengths);
2069 _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
2071 _predicted_scan_only_scan_time_ms =
2072 predict_scan_only_time_ms(_recorded_scan_only_regions);
2073 _predicted_rs_update_time_ms =
2074 predict_rs_update_time_ms(_g1->pending_card_num());
2075 _predicted_rs_scan_time_ms =
2076 predict_rs_scan_time_ms(_predicted_cards_scanned);
2077 _predicted_object_copy_time_ms =
2078 predict_object_copy_time_ms(_predicted_bytes_to_copy);
2079 _predicted_constant_other_time_ms =
2080 predict_constant_other_time_ms();
2081 _predicted_young_other_time_ms =
2082 predict_young_other_time_ms(_recorded_young_regions);
2083 _predicted_non_young_other_time_ms =
2084 predict_non_young_other_time_ms(_recorded_non_young_regions);
2086 _predicted_pause_time_ms =
2087 _predicted_scan_only_scan_time_ms +
2088 _predicted_rs_update_time_ms +
2089 _predicted_rs_scan_time_ms +
2090 _predicted_object_copy_time_ms +
2091 _predicted_constant_other_time_ms +
2092 _predicted_young_other_time_ms +
2093 _predicted_non_young_other_time_ms;
2094 #endif // PREDICTIONS_VERBOSE
2095 }
2097 void G1CollectorPolicy::check_if_region_is_too_expensive(double
2098 predicted_time_ms) {
2099 // I don't think we need to do this when in young GC mode since
2100 // marking will be initiated next time we hit the soft limit anyway...
2101 if (predicted_time_ms > _expensive_region_limit_ms) {
2102 if (!in_young_gc_mode()) {
2103 set_full_young_gcs(true);
2104 _should_initiate_conc_mark = true;
2105 } else
2106 // no point in doing another partial one
2107 _should_revert_to_full_young_gcs = true;
2108 }
2109 }
2111 // </NEW PREDICTION>
2114 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
2115 double elapsed_ms) {
2116 _recent_gc_times_ms->add(elapsed_ms);
2117 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
2118 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
2119 }
2121 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
2122 if (_recent_pause_times_ms->num() == 0) return (double) MaxGCPauseMillis;
2123 else return _recent_pause_times_ms->avg();
2124 }
2126 double G1CollectorPolicy::recent_avg_time_for_CH_strong_ms() {
2127 if (_recent_CH_strong_roots_times_ms->num() == 0)
2128 return (double)MaxGCPauseMillis/3.0;
2129 else return _recent_CH_strong_roots_times_ms->avg();
2130 }
2132 double G1CollectorPolicy::recent_avg_time_for_G1_strong_ms() {
2133 if (_recent_G1_strong_roots_times_ms->num() == 0)
2134 return (double)MaxGCPauseMillis/3.0;
2135 else return _recent_G1_strong_roots_times_ms->avg();
2136 }
2138 double G1CollectorPolicy::recent_avg_time_for_evac_ms() {
2139 if (_recent_evac_times_ms->num() == 0) return (double)MaxGCPauseMillis/3.0;
2140 else return _recent_evac_times_ms->avg();
2141 }
2143 int G1CollectorPolicy::number_of_recent_gcs() {
2144 assert(_recent_CH_strong_roots_times_ms->num() ==
2145 _recent_G1_strong_roots_times_ms->num(), "Sequence out of sync");
2146 assert(_recent_G1_strong_roots_times_ms->num() ==
2147 _recent_evac_times_ms->num(), "Sequence out of sync");
2148 assert(_recent_evac_times_ms->num() ==
2149 _recent_pause_times_ms->num(), "Sequence out of sync");
2150 assert(_recent_pause_times_ms->num() ==
2151 _recent_CS_bytes_used_before->num(), "Sequence out of sync");
2152 assert(_recent_CS_bytes_used_before->num() ==
2153 _recent_CS_bytes_surviving->num(), "Sequence out of sync");
2154 return _recent_pause_times_ms->num();
2155 }
2157 double G1CollectorPolicy::recent_avg_survival_fraction() {
2158 return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
2159 _recent_CS_bytes_used_before);
2160 }
2162 double G1CollectorPolicy::last_survival_fraction() {
2163 return last_survival_fraction_work(_recent_CS_bytes_surviving,
2164 _recent_CS_bytes_used_before);
2165 }
2167 double
2168 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
2169 TruncatedSeq* before) {
2170 assert(surviving->num() == before->num(), "Sequence out of sync");
2171 if (before->sum() > 0.0) {
2172 double recent_survival_rate = surviving->sum() / before->sum();
2173 // We exempt parallel collection from this check because Alloc Buffer
2174 // fragmentation can produce negative collections.
2175 // Further, we're now always doing parallel collection. But I'm still
2176 // leaving this here as a placeholder for a more precise assertion later.
2177 // (DLD, 10/05.)
2178 assert((true || ParallelGCThreads > 0) ||
2179 _g1->evacuation_failed() ||
2180 recent_survival_rate <= 1.0, "Or bad frac");
2181 return recent_survival_rate;
2182 } else {
2183 return 1.0; // Be conservative.
2184 }
2185 }
2187 double
2188 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
2189 TruncatedSeq* before) {
2190 assert(surviving->num() == before->num(), "Sequence out of sync");
2191 if (surviving->num() > 0 && before->last() > 0.0) {
2192 double last_survival_rate = surviving->last() / before->last();
2193 // We exempt parallel collection from this check because Alloc Buffer
2194 // fragmentation can produce negative collections.
2195 // Further, we're now always doing parallel collection. But I'm still
2196 // leaving this here as a placeholder for a more precise assertion later.
2197 // (DLD, 10/05.)
2198 assert((true || ParallelGCThreads > 0) ||
2199 last_survival_rate <= 1.0, "Or bad frac");
2200 return last_survival_rate;
2201 } else {
2202 return 1.0;
2203 }
2204 }
2206 static const int survival_min_obs = 5;
2207 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
2208 static const double min_survival_rate = 0.1;
2210 double
2211 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
2212 double latest) {
2213 double res = avg;
2214 if (number_of_recent_gcs() < survival_min_obs) {
2215 res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
2216 }
2217 res = MAX2(res, latest);
2218 res = MAX2(res, min_survival_rate);
2219 // In the parallel case, LAB fragmentation can produce "negative
2220 // collections"; so can evac failure. Cap at 1.0
2221 res = MIN2(res, 1.0);
2222 return res;
2223 }
2225 size_t G1CollectorPolicy::expansion_amount() {
2226 if ((int)(recent_avg_pause_time_ratio() * 100.0) > G1GCPercent) {
2227 // We will double the existing space, or take
2228 // G1ExpandByPercentOfAvailable % of the available expansion
2229 // space, whichever is smaller, bounded below by a minimum
2230 // expansion (unless that's all that's left.)
2231 const size_t min_expand_bytes = 1*M;
2232 size_t reserved_bytes = _g1->g1_reserved_obj_bytes();
2233 size_t committed_bytes = _g1->capacity();
2234 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
2235 size_t expand_bytes;
2236 size_t expand_bytes_via_pct =
2237 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
2238 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
2239 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
2240 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
2241 if (G1PolicyVerbose > 1) {
2242 gclog_or_tty->print("Decided to expand: ratio = %5.2f, "
2243 "committed = %d%s, uncommited = %d%s, via pct = %d%s.\n"
2244 " Answer = %d.\n",
2245 recent_avg_pause_time_ratio(),
2246 byte_size_in_proper_unit(committed_bytes),
2247 proper_unit_for_byte_size(committed_bytes),
2248 byte_size_in_proper_unit(uncommitted_bytes),
2249 proper_unit_for_byte_size(uncommitted_bytes),
2250 byte_size_in_proper_unit(expand_bytes_via_pct),
2251 proper_unit_for_byte_size(expand_bytes_via_pct),
2252 byte_size_in_proper_unit(expand_bytes),
2253 proper_unit_for_byte_size(expand_bytes));
2254 }
2255 return expand_bytes;
2256 } else {
2257 return 0;
2258 }
2259 }
2261 void G1CollectorPolicy::note_start_of_mark_thread() {
2262 _mark_thread_startup_sec = os::elapsedTime();
2263 }
2265 class CountCSClosure: public HeapRegionClosure {
2266 G1CollectorPolicy* _g1_policy;
2267 public:
2268 CountCSClosure(G1CollectorPolicy* g1_policy) :
2269 _g1_policy(g1_policy) {}
2270 bool doHeapRegion(HeapRegion* r) {
2271 _g1_policy->_bytes_in_collection_set_before_gc += r->used();
2272 return false;
2273 }
2274 };
2276 void G1CollectorPolicy::count_CS_bytes_used() {
2277 CountCSClosure cs_closure(this);
2278 _g1->collection_set_iterate(&cs_closure);
2279 }
2281 static void print_indent(int level) {
2282 for (int j = 0; j < level+1; ++j)
2283 gclog_or_tty->print(" ");
2284 }
2286 void G1CollectorPolicy::print_summary (int level,
2287 const char* str,
2288 NumberSeq* seq) const {
2289 double sum = seq->sum();
2290 print_indent(level);
2291 gclog_or_tty->print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
2292 str, sum / 1000.0, seq->avg());
2293 }
2295 void G1CollectorPolicy::print_summary_sd (int level,
2296 const char* str,
2297 NumberSeq* seq) const {
2298 print_summary(level, str, seq);
2299 print_indent(level + 5);
2300 gclog_or_tty->print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2301 seq->num(), seq->sd(), seq->maximum());
2302 }
2304 void G1CollectorPolicy::check_other_times(int level,
2305 NumberSeq* other_times_ms,
2306 NumberSeq* calc_other_times_ms) const {
2307 bool should_print = false;
2309 double max_sum = MAX2(fabs(other_times_ms->sum()),
2310 fabs(calc_other_times_ms->sum()));
2311 double min_sum = MIN2(fabs(other_times_ms->sum()),
2312 fabs(calc_other_times_ms->sum()));
2313 double sum_ratio = max_sum / min_sum;
2314 if (sum_ratio > 1.1) {
2315 should_print = true;
2316 print_indent(level + 1);
2317 gclog_or_tty->print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
2318 }
2320 double max_avg = MAX2(fabs(other_times_ms->avg()),
2321 fabs(calc_other_times_ms->avg()));
2322 double min_avg = MIN2(fabs(other_times_ms->avg()),
2323 fabs(calc_other_times_ms->avg()));
2324 double avg_ratio = max_avg / min_avg;
2325 if (avg_ratio > 1.1) {
2326 should_print = true;
2327 print_indent(level + 1);
2328 gclog_or_tty->print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
2329 }
2331 if (other_times_ms->sum() < -0.01) {
2332 print_indent(level + 1);
2333 gclog_or_tty->print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
2334 }
2336 if (other_times_ms->avg() < -0.01) {
2337 print_indent(level + 1);
2338 gclog_or_tty->print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
2339 }
2341 if (calc_other_times_ms->sum() < -0.01) {
2342 should_print = true;
2343 print_indent(level + 1);
2344 gclog_or_tty->print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
2345 }
2347 if (calc_other_times_ms->avg() < -0.01) {
2348 should_print = true;
2349 print_indent(level + 1);
2350 gclog_or_tty->print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
2351 }
2353 if (should_print)
2354 print_summary(level, "Other(Calc)", calc_other_times_ms);
2355 }
2357 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
2358 bool parallel = ParallelGCThreads > 0;
2359 MainBodySummary* body_summary = summary->main_body_summary();
2360 if (summary->get_total_seq()->num() > 0) {
2361 print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
2362 if (body_summary != NULL) {
2363 print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
2364 if (parallel) {
2365 print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
2366 print_summary(2, "Update RS", body_summary->get_update_rs_seq());
2367 print_summary(2, "Ext Root Scanning",
2368 body_summary->get_ext_root_scan_seq());
2369 print_summary(2, "Mark Stack Scanning",
2370 body_summary->get_mark_stack_scan_seq());
2371 print_summary(2, "Scan-Only Scanning",
2372 body_summary->get_scan_only_seq());
2373 print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
2374 print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
2375 print_summary(2, "Termination", body_summary->get_termination_seq());
2376 print_summary(2, "Other", body_summary->get_parallel_other_seq());
2377 {
2378 NumberSeq* other_parts[] = {
2379 body_summary->get_update_rs_seq(),
2380 body_summary->get_ext_root_scan_seq(),
2381 body_summary->get_mark_stack_scan_seq(),
2382 body_summary->get_scan_only_seq(),
2383 body_summary->get_scan_rs_seq(),
2384 body_summary->get_obj_copy_seq(),
2385 body_summary->get_termination_seq()
2386 };
2387 NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
2388 7, other_parts);
2389 check_other_times(2, body_summary->get_parallel_other_seq(),
2390 &calc_other_times_ms);
2391 }
2392 print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
2393 print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
2394 } else {
2395 print_summary(1, "Update RS", body_summary->get_update_rs_seq());
2396 print_summary(1, "Ext Root Scanning",
2397 body_summary->get_ext_root_scan_seq());
2398 print_summary(1, "Mark Stack Scanning",
2399 body_summary->get_mark_stack_scan_seq());
2400 print_summary(1, "Scan-Only Scanning",
2401 body_summary->get_scan_only_seq());
2402 print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
2403 print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
2404 }
2405 }
2406 print_summary(1, "Other", summary->get_other_seq());
2407 {
2408 NumberSeq calc_other_times_ms;
2409 if (body_summary != NULL) {
2410 // not abandoned
2411 if (parallel) {
2412 // parallel
2413 NumberSeq* other_parts[] = {
2414 body_summary->get_satb_drain_seq(),
2415 body_summary->get_parallel_seq(),
2416 body_summary->get_clear_ct_seq()
2417 };
2418 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2419 3, other_parts);
2420 } else {
2421 // serial
2422 NumberSeq* other_parts[] = {
2423 body_summary->get_satb_drain_seq(),
2424 body_summary->get_update_rs_seq(),
2425 body_summary->get_ext_root_scan_seq(),
2426 body_summary->get_mark_stack_scan_seq(),
2427 body_summary->get_scan_only_seq(),
2428 body_summary->get_scan_rs_seq(),
2429 body_summary->get_obj_copy_seq()
2430 };
2431 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2432 7, other_parts);
2433 }
2434 } else {
2435 // abandoned
2436 calc_other_times_ms = NumberSeq();
2437 }
2438 check_other_times(1, summary->get_other_seq(), &calc_other_times_ms);
2439 }
2440 } else {
2441 print_indent(0);
2442 gclog_or_tty->print_cr("none");
2443 }
2444 gclog_or_tty->print_cr("");
2445 }
2447 void
2448 G1CollectorPolicy::print_abandoned_summary(PauseSummary* summary) const {
2449 bool printed = false;
2450 if (summary->get_total_seq()->num() > 0) {
2451 printed = true;
2452 print_summary(summary);
2453 }
2454 if (!printed) {
2455 print_indent(0);
2456 gclog_or_tty->print_cr("none");
2457 gclog_or_tty->print_cr("");
2458 }
2459 }
2461 void G1CollectorPolicy::print_tracing_info() const {
2462 if (TraceGen0Time) {
2463 gclog_or_tty->print_cr("ALL PAUSES");
2464 print_summary_sd(0, "Total", _all_pause_times_ms);
2465 gclog_or_tty->print_cr("");
2466 gclog_or_tty->print_cr("");
2467 gclog_or_tty->print_cr(" Full Young GC Pauses: %8d", _full_young_pause_num);
2468 gclog_or_tty->print_cr(" Partial Young GC Pauses: %8d", _partial_young_pause_num);
2469 gclog_or_tty->print_cr("");
2471 gclog_or_tty->print_cr("EVACUATION PAUSES");
2472 print_summary(_summary);
2474 gclog_or_tty->print_cr("ABANDONED PAUSES");
2475 print_abandoned_summary(_abandoned_summary);
2477 gclog_or_tty->print_cr("MISC");
2478 print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
2479 print_summary_sd(0, "Yields", _all_yield_times_ms);
2480 for (int i = 0; i < _aux_num; ++i) {
2481 if (_all_aux_times_ms[i].num() > 0) {
2482 char buffer[96];
2483 sprintf(buffer, "Aux%d", i);
2484 print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
2485 }
2486 }
2488 size_t all_region_num = _region_num_young + _region_num_tenured;
2489 gclog_or_tty->print_cr(" New Regions %8d, Young %8d (%6.2lf%%), "
2490 "Tenured %8d (%6.2lf%%)",
2491 all_region_num,
2492 _region_num_young,
2493 (double) _region_num_young / (double) all_region_num * 100.0,
2494 _region_num_tenured,
2495 (double) _region_num_tenured / (double) all_region_num * 100.0);
2496 }
2497 if (TraceGen1Time) {
2498 if (_all_full_gc_times_ms->num() > 0) {
2499 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2500 _all_full_gc_times_ms->num(),
2501 _all_full_gc_times_ms->sum() / 1000.0);
2502 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
2503 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2504 _all_full_gc_times_ms->sd(),
2505 _all_full_gc_times_ms->maximum());
2506 }
2507 }
2508 }
2510 void G1CollectorPolicy::print_yg_surv_rate_info() const {
2511 #ifndef PRODUCT
2512 _short_lived_surv_rate_group->print_surv_rate_summary();
2513 // add this call for any other surv rate groups
2514 #endif // PRODUCT
2515 }
2517 bool
2518 G1CollectorPolicy::should_add_next_region_to_young_list() {
2519 assert(in_young_gc_mode(), "should be in young GC mode");
2520 bool ret;
2521 size_t young_list_length = _g1->young_list_length();
2522 size_t young_list_max_length = _young_list_target_length;
2523 if (G1FixedEdenSize) {
2524 young_list_max_length -= _max_survivor_regions;
2525 }
2526 if (young_list_length < young_list_max_length) {
2527 ret = true;
2528 ++_region_num_young;
2529 } else {
2530 ret = false;
2531 ++_region_num_tenured;
2532 }
2534 return ret;
2535 }
2537 #ifndef PRODUCT
2538 // for debugging, bit of a hack...
2539 static char*
2540 region_num_to_mbs(int length) {
2541 static char buffer[64];
2542 double bytes = (double) (length * HeapRegion::GrainBytes);
2543 double mbs = bytes / (double) (1024 * 1024);
2544 sprintf(buffer, "%7.2lfMB", mbs);
2545 return buffer;
2546 }
2547 #endif // PRODUCT
2549 size_t G1CollectorPolicy::max_regions(int purpose) {
2550 switch (purpose) {
2551 case GCAllocForSurvived:
2552 return _max_survivor_regions;
2553 case GCAllocForTenured:
2554 return REGIONS_UNLIMITED;
2555 default:
2556 ShouldNotReachHere();
2557 return REGIONS_UNLIMITED;
2558 };
2559 }
2561 // Calculates survivor space parameters.
2562 void G1CollectorPolicy::calculate_survivors_policy()
2563 {
2564 if (!G1UseSurvivorSpaces) {
2565 return;
2566 }
2567 if (G1FixedSurvivorSpaceSize == 0) {
2568 _max_survivor_regions = _young_list_target_length / SurvivorRatio;
2569 } else {
2570 _max_survivor_regions = G1FixedSurvivorSpaceSize / HeapRegion::GrainBytes;
2571 }
2573 if (G1FixedTenuringThreshold) {
2574 _tenuring_threshold = MaxTenuringThreshold;
2575 } else {
2576 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
2577 HeapRegion::GrainWords * _max_survivor_regions);
2578 }
2579 }
2581 bool
2582 G1CollectorPolicy_BestRegionsFirst::should_do_collection_pause(size_t
2583 word_size) {
2584 assert(_g1->regions_accounted_for(), "Region leakage!");
2585 // Initiate a pause when we reach the steady-state "used" target.
2586 size_t used_hard = (_g1->capacity() / 100) * G1SteadyStateUsed;
2587 size_t used_soft =
2588 MAX2((_g1->capacity() / 100) * (G1SteadyStateUsed - G1SteadyStateUsedDelta),
2589 used_hard/2);
2590 size_t used = _g1->used();
2592 double max_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
2594 size_t young_list_length = _g1->young_list_length();
2595 size_t young_list_max_length = _young_list_target_length;
2596 if (G1FixedEdenSize) {
2597 young_list_max_length -= _max_survivor_regions;
2598 }
2599 bool reached_target_length = young_list_length >= young_list_max_length;
2601 if (in_young_gc_mode()) {
2602 if (reached_target_length) {
2603 assert( young_list_length > 0 && _g1->young_list_length() > 0,
2604 "invariant" );
2605 _target_pause_time_ms = max_pause_time_ms;
2606 return true;
2607 }
2608 } else {
2609 guarantee( false, "should not reach here" );
2610 }
2612 return false;
2613 }
2615 #ifndef PRODUCT
2616 class HRSortIndexIsOKClosure: public HeapRegionClosure {
2617 CollectionSetChooser* _chooser;
2618 public:
2619 HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
2620 _chooser(chooser) {}
2622 bool doHeapRegion(HeapRegion* r) {
2623 if (!r->continuesHumongous()) {
2624 assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
2625 }
2626 return false;
2627 }
2628 };
2630 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
2631 HRSortIndexIsOKClosure cl(_collectionSetChooser);
2632 _g1->heap_region_iterate(&cl);
2633 return true;
2634 }
2635 #endif
2637 void
2638 G1CollectorPolicy_BestRegionsFirst::
2639 record_collection_pause_start(double start_time_sec, size_t start_used) {
2640 G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
2641 }
2643 class NextNonCSElemFinder: public HeapRegionClosure {
2644 HeapRegion* _res;
2645 public:
2646 NextNonCSElemFinder(): _res(NULL) {}
2647 bool doHeapRegion(HeapRegion* r) {
2648 if (!r->in_collection_set()) {
2649 _res = r;
2650 return true;
2651 } else {
2652 return false;
2653 }
2654 }
2655 HeapRegion* res() { return _res; }
2656 };
2658 class KnownGarbageClosure: public HeapRegionClosure {
2659 CollectionSetChooser* _hrSorted;
2661 public:
2662 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
2663 _hrSorted(hrSorted)
2664 {}
2666 bool doHeapRegion(HeapRegion* r) {
2667 // We only include humongous regions in collection
2668 // sets when concurrent mark shows that their contained object is
2669 // unreachable.
2671 // Do we have any marking information for this region?
2672 if (r->is_marked()) {
2673 // We don't include humongous regions in collection
2674 // sets because we collect them immediately at the end of a marking
2675 // cycle. We also don't include young regions because we *must*
2676 // include them in the next collection pause.
2677 if (!r->isHumongous() && !r->is_young()) {
2678 _hrSorted->addMarkedHeapRegion(r);
2679 }
2680 }
2681 return false;
2682 }
2683 };
2685 class ParKnownGarbageHRClosure: public HeapRegionClosure {
2686 CollectionSetChooser* _hrSorted;
2687 jint _marked_regions_added;
2688 jint _chunk_size;
2689 jint _cur_chunk_idx;
2690 jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
2691 int _worker;
2692 int _invokes;
2694 void get_new_chunk() {
2695 _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
2696 _cur_chunk_end = _cur_chunk_idx + _chunk_size;
2697 }
2698 void add_region(HeapRegion* r) {
2699 if (_cur_chunk_idx == _cur_chunk_end) {
2700 get_new_chunk();
2701 }
2702 assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
2703 _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
2704 _marked_regions_added++;
2705 _cur_chunk_idx++;
2706 }
2708 public:
2709 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
2710 jint chunk_size,
2711 int worker) :
2712 _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
2713 _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
2714 _invokes(0)
2715 {}
2717 bool doHeapRegion(HeapRegion* r) {
2718 // We only include humongous regions in collection
2719 // sets when concurrent mark shows that their contained object is
2720 // unreachable.
2721 _invokes++;
2723 // Do we have any marking information for this region?
2724 if (r->is_marked()) {
2725 // We don't include humongous regions in collection
2726 // sets because we collect them immediately at the end of a marking
2727 // cycle.
2728 // We also do not include young regions in collection sets
2729 if (!r->isHumongous() && !r->is_young()) {
2730 add_region(r);
2731 }
2732 }
2733 return false;
2734 }
2735 jint marked_regions_added() { return _marked_regions_added; }
2736 int invokes() { return _invokes; }
2737 };
2739 class ParKnownGarbageTask: public AbstractGangTask {
2740 CollectionSetChooser* _hrSorted;
2741 jint _chunk_size;
2742 G1CollectedHeap* _g1;
2743 public:
2744 ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
2745 AbstractGangTask("ParKnownGarbageTask"),
2746 _hrSorted(hrSorted), _chunk_size(chunk_size),
2747 _g1(G1CollectedHeap::heap())
2748 {}
2750 void work(int i) {
2751 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
2752 // Back to zero for the claim value.
2753 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
2754 HeapRegion::InitialClaimValue);
2755 jint regions_added = parKnownGarbageCl.marked_regions_added();
2756 _hrSorted->incNumMarkedHeapRegions(regions_added);
2757 if (G1PrintParCleanupStats) {
2758 gclog_or_tty->print(" Thread %d called %d times, added %d regions to list.\n",
2759 i, parKnownGarbageCl.invokes(), regions_added);
2760 }
2761 }
2762 };
2764 void
2765 G1CollectorPolicy_BestRegionsFirst::
2766 record_concurrent_mark_cleanup_end(size_t freed_bytes,
2767 size_t max_live_bytes) {
2768 double start;
2769 if (G1PrintParCleanupStats) start = os::elapsedTime();
2770 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
2772 _collectionSetChooser->clearMarkedHeapRegions();
2773 double clear_marked_end;
2774 if (G1PrintParCleanupStats) {
2775 clear_marked_end = os::elapsedTime();
2776 gclog_or_tty->print_cr(" clear marked regions + work1: %8.3f ms.",
2777 (clear_marked_end - start)*1000.0);
2778 }
2779 if (ParallelGCThreads > 0) {
2780 const size_t OverpartitionFactor = 4;
2781 const size_t MinChunkSize = 8;
2782 const size_t ChunkSize =
2783 MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
2784 MinChunkSize);
2785 _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
2786 ChunkSize);
2787 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
2788 (int) ChunkSize);
2789 _g1->workers()->run_task(&parKnownGarbageTask);
2791 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
2792 "sanity check");
2793 } else {
2794 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
2795 _g1->heap_region_iterate(&knownGarbagecl);
2796 }
2797 double known_garbage_end;
2798 if (G1PrintParCleanupStats) {
2799 known_garbage_end = os::elapsedTime();
2800 gclog_or_tty->print_cr(" compute known garbage: %8.3f ms.",
2801 (known_garbage_end - clear_marked_end)*1000.0);
2802 }
2803 _collectionSetChooser->sortMarkedHeapRegions();
2804 double sort_end;
2805 if (G1PrintParCleanupStats) {
2806 sort_end = os::elapsedTime();
2807 gclog_or_tty->print_cr(" sorting: %8.3f ms.",
2808 (sort_end - known_garbage_end)*1000.0);
2809 }
2811 record_concurrent_mark_cleanup_end_work2();
2812 double work2_end;
2813 if (G1PrintParCleanupStats) {
2814 work2_end = os::elapsedTime();
2815 gclog_or_tty->print_cr(" work2: %8.3f ms.",
2816 (work2_end - sort_end)*1000.0);
2817 }
2818 }
2820 // Add the heap region to the collection set and return the conservative
2821 // estimate of the number of live bytes.
2822 void G1CollectorPolicy::
2823 add_to_collection_set(HeapRegion* hr) {
2824 if (G1PrintRegions) {
2825 gclog_or_tty->print_cr("added region to cset %d:["PTR_FORMAT", "PTR_FORMAT"], "
2826 "top "PTR_FORMAT", young %s",
2827 hr->hrs_index(), hr->bottom(), hr->end(),
2828 hr->top(), (hr->is_young()) ? "YES" : "NO");
2829 }
2831 if (_g1->mark_in_progress())
2832 _g1->concurrent_mark()->registerCSetRegion(hr);
2834 assert(!hr->in_collection_set(),
2835 "should not already be in the CSet");
2836 hr->set_in_collection_set(true);
2837 hr->set_next_in_collection_set(_collection_set);
2838 _collection_set = hr;
2839 _collection_set_size++;
2840 _collection_set_bytes_used_before += hr->used();
2841 _g1->register_region_with_in_cset_fast_test(hr);
2842 }
2844 void
2845 G1CollectorPolicy_BestRegionsFirst::
2846 choose_collection_set() {
2847 double non_young_start_time_sec;
2848 start_recording_regions();
2850 guarantee(_target_pause_time_ms > -1.0,
2851 "_target_pause_time_ms should have been set!");
2852 assert(_collection_set == NULL, "Precondition");
2854 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2855 double predicted_pause_time_ms = base_time_ms;
2857 double target_time_ms = _target_pause_time_ms;
2858 double time_remaining_ms = target_time_ms - base_time_ms;
2860 // the 10% and 50% values are arbitrary...
2861 if (time_remaining_ms < 0.10*target_time_ms) {
2862 time_remaining_ms = 0.50 * target_time_ms;
2863 _within_target = false;
2864 } else {
2865 _within_target = true;
2866 }
2868 // We figure out the number of bytes available for future to-space.
2869 // For new regions without marking information, we must assume the
2870 // worst-case of complete survival. If we have marking information for a
2871 // region, we can bound the amount of live data. We can add a number of
2872 // such regions, as long as the sum of the live data bounds does not
2873 // exceed the available evacuation space.
2874 size_t max_live_bytes = _g1->free_regions() * HeapRegion::GrainBytes;
2876 size_t expansion_bytes =
2877 _g1->expansion_regions() * HeapRegion::GrainBytes;
2879 _collection_set_bytes_used_before = 0;
2880 _collection_set_size = 0;
2882 // Adjust for expansion and slop.
2883 max_live_bytes = max_live_bytes + expansion_bytes;
2885 assert(_g1->regions_accounted_for(), "Region leakage!");
2887 HeapRegion* hr;
2888 if (in_young_gc_mode()) {
2889 double young_start_time_sec = os::elapsedTime();
2891 if (G1PolicyVerbose > 0) {
2892 gclog_or_tty->print_cr("Adding %d young regions to the CSet",
2893 _g1->young_list_length());
2894 }
2895 _young_cset_length = 0;
2896 _last_young_gc_full = full_young_gcs() ? true : false;
2897 if (_last_young_gc_full)
2898 ++_full_young_pause_num;
2899 else
2900 ++_partial_young_pause_num;
2901 hr = _g1->pop_region_from_young_list();
2902 while (hr != NULL) {
2904 assert( hr->young_index_in_cset() == -1, "invariant" );
2905 assert( hr->age_in_surv_rate_group() != -1, "invariant" );
2906 hr->set_young_index_in_cset((int) _young_cset_length);
2908 ++_young_cset_length;
2909 double predicted_time_ms = predict_region_elapsed_time_ms(hr, true);
2910 time_remaining_ms -= predicted_time_ms;
2911 predicted_pause_time_ms += predicted_time_ms;
2912 assert(!hr->in_collection_set(), "invariant");
2913 add_to_collection_set(hr);
2914 record_cset_region(hr, true);
2915 max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
2916 if (G1PolicyVerbose > 0) {
2917 gclog_or_tty->print_cr(" Added [" PTR_FORMAT ", " PTR_FORMAT") to CS.",
2918 hr->bottom(), hr->end());
2919 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2920 max_live_bytes/K);
2921 }
2922 hr = _g1->pop_region_from_young_list();
2923 }
2925 record_scan_only_regions(_g1->young_list_scan_only_length());
2927 double young_end_time_sec = os::elapsedTime();
2928 _recorded_young_cset_choice_time_ms =
2929 (young_end_time_sec - young_start_time_sec) * 1000.0;
2931 non_young_start_time_sec = os::elapsedTime();
2933 if (_young_cset_length > 0 && _last_young_gc_full) {
2934 // don't bother adding more regions...
2935 goto choose_collection_set_end;
2936 }
2937 }
2939 if (!in_young_gc_mode() || !full_young_gcs()) {
2940 bool should_continue = true;
2941 NumberSeq seq;
2942 double avg_prediction = 100000000000000000.0; // something very large
2943 do {
2944 hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
2945 avg_prediction);
2946 if (hr != NULL) {
2947 double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
2948 time_remaining_ms -= predicted_time_ms;
2949 predicted_pause_time_ms += predicted_time_ms;
2950 add_to_collection_set(hr);
2951 record_cset_region(hr, false);
2952 max_live_bytes -= MIN2(hr->max_live_bytes(), max_live_bytes);
2953 if (G1PolicyVerbose > 0) {
2954 gclog_or_tty->print_cr(" (" SIZE_FORMAT " KB left in heap.)",
2955 max_live_bytes/K);
2956 }
2957 seq.add(predicted_time_ms);
2958 avg_prediction = seq.avg() + seq.sd();
2959 }
2960 should_continue =
2961 ( hr != NULL) &&
2962 ( (adaptive_young_list_length()) ? time_remaining_ms > 0.0
2963 : _collection_set_size < _young_list_fixed_length );
2964 } while (should_continue);
2966 if (!adaptive_young_list_length() &&
2967 _collection_set_size < _young_list_fixed_length)
2968 _should_revert_to_full_young_gcs = true;
2969 }
2971 choose_collection_set_end:
2972 count_CS_bytes_used();
2974 end_recording_regions();
2976 double non_young_end_time_sec = os::elapsedTime();
2977 _recorded_non_young_cset_choice_time_ms =
2978 (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
2979 }
2981 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
2982 G1CollectorPolicy::record_full_collection_end();
2983 _collectionSetChooser->updateAfterFullCollection();
2984 }
2986 void G1CollectorPolicy_BestRegionsFirst::
2987 expand_if_possible(size_t numRegions) {
2988 size_t expansion_bytes = numRegions * HeapRegion::GrainBytes;
2989 _g1->expand(expansion_bytes);
2990 }
2992 void G1CollectorPolicy_BestRegionsFirst::
2993 record_collection_pause_end(bool abandoned) {
2994 G1CollectorPolicy::record_collection_pause_end(abandoned);
2995 assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
2996 }
2998 // Local Variables: ***
2999 // c-indentation-style: gnu ***
3000 // End: ***