Thu, 05 Apr 2012 13:57:23 -0400
7127697: G1: remove dead code after recent concurrent mark changes
Summary: Removed lots of dead code after some recent conc mark changes.
Reviewed-by: brutisso, johnc
1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTORPOLICY_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTORPOLICY_HPP
28 #include "gc_implementation/g1/collectionSetChooser.hpp"
29 #include "gc_implementation/g1/g1MMUTracker.hpp"
30 #include "memory/collectorPolicy.hpp"
32 // A G1CollectorPolicy makes policy decisions that determine the
33 // characteristics of the collector. Examples include:
34 // * choice of collection set.
35 // * when to collect.
37 class HeapRegion;
38 class CollectionSetChooser;
40 // Yes, this is a bit unpleasant... but it saves replicating the same thing
41 // over and over again and introducing subtle problems through small typos and
42 // cutting and pasting mistakes. The macros below introduces a number
43 // sequnce into the following two classes and the methods that access it.
45 #define define_num_seq(name) \
46 private: \
47 NumberSeq _all_##name##_times_ms; \
48 public: \
49 void record_##name##_time_ms(double ms) { \
50 _all_##name##_times_ms.add(ms); \
51 } \
52 NumberSeq* get_##name##_seq() { \
53 return &_all_##name##_times_ms; \
54 }
56 class MainBodySummary;
58 class PauseSummary: public CHeapObj {
59 define_num_seq(total)
60 define_num_seq(other)
62 public:
63 virtual MainBodySummary* main_body_summary() { return NULL; }
64 };
66 class MainBodySummary: public CHeapObj {
67 define_num_seq(root_region_scan_wait)
68 define_num_seq(parallel) // parallel only
69 define_num_seq(ext_root_scan)
70 define_num_seq(satb_filtering)
71 define_num_seq(update_rs)
72 define_num_seq(scan_rs)
73 define_num_seq(obj_copy)
74 define_num_seq(termination) // parallel only
75 define_num_seq(parallel_other) // parallel only
76 define_num_seq(clear_ct)
77 };
79 class Summary: public PauseSummary,
80 public MainBodySummary {
81 public:
82 virtual MainBodySummary* main_body_summary() { return this; }
83 };
85 // There are three command line options related to the young gen size:
86 // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is
87 // just a short form for NewSize==MaxNewSize). G1 will use its internal
88 // heuristics to calculate the actual young gen size, so these options
89 // basically only limit the range within which G1 can pick a young gen
90 // size. Also, these are general options taking byte sizes. G1 will
91 // internally work with a number of regions instead. So, some rounding
92 // will occur.
93 //
94 // If nothing related to the the young gen size is set on the command
95 // line we should allow the young gen to be between
96 // G1DefaultMinNewGenPercent and G1DefaultMaxNewGenPercent of the
97 // heap size. This means that every time the heap size changes the
98 // limits for the young gen size will be updated.
99 //
100 // If only -XX:NewSize is set we should use the specified value as the
101 // minimum size for young gen. Still using G1DefaultMaxNewGenPercent
102 // of the heap as maximum.
103 //
104 // If only -XX:MaxNewSize is set we should use the specified value as the
105 // maximum size for young gen. Still using G1DefaultMinNewGenPercent
106 // of the heap as minimum.
107 //
108 // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.
109 // No updates when the heap size changes. There is a special case when
110 // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a
111 // different heuristic for calculating the collection set when we do mixed
112 // collection.
113 //
114 // If only -XX:NewRatio is set we should use the specified ratio of the heap
115 // as both min and max. This will be interpreted as "fixed" just like the
116 // NewSize==MaxNewSize case above. But we will update the min and max
117 // everytime the heap size changes.
118 //
119 // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
120 // combined with either NewSize or MaxNewSize. (A warning message is printed.)
121 class G1YoungGenSizer : public CHeapObj {
122 private:
123 enum SizerKind {
124 SizerDefaults,
125 SizerNewSizeOnly,
126 SizerMaxNewSizeOnly,
127 SizerMaxAndNewSize,
128 SizerNewRatio
129 };
130 SizerKind _sizer_kind;
131 size_t _min_desired_young_length;
132 size_t _max_desired_young_length;
133 bool _adaptive_size;
134 size_t calculate_default_min_length(size_t new_number_of_heap_regions);
135 size_t calculate_default_max_length(size_t new_number_of_heap_regions);
137 public:
138 G1YoungGenSizer();
139 void heap_size_changed(size_t new_number_of_heap_regions);
140 size_t min_desired_young_length() {
141 return _min_desired_young_length;
142 }
143 size_t max_desired_young_length() {
144 return _max_desired_young_length;
145 }
146 bool adaptive_young_list_length() {
147 return _adaptive_size;
148 }
149 };
151 class G1CollectorPolicy: public CollectorPolicy {
152 private:
153 // either equal to the number of parallel threads, if ParallelGCThreads
154 // has been set, or 1 otherwise
155 int _parallel_gc_threads;
157 // The number of GC threads currently active.
158 uintx _no_of_gc_threads;
160 enum SomePrivateConstants {
161 NumPrevPausesForHeuristics = 10
162 };
164 G1MMUTracker* _mmu_tracker;
166 void initialize_flags();
168 void initialize_all() {
169 initialize_flags();
170 initialize_size_info();
171 initialize_perm_generation(PermGen::MarkSweepCompact);
172 }
174 CollectionSetChooser* _collectionSetChooser;
176 double _cur_collection_start_sec;
177 size_t _cur_collection_pause_used_at_start_bytes;
178 size_t _cur_collection_pause_used_regions_at_start;
179 double _cur_collection_par_time_ms;
181 double _cur_collection_code_root_fixup_time_ms;
183 double _cur_clear_ct_time_ms;
184 double _cur_ref_proc_time_ms;
185 double _cur_ref_enq_time_ms;
187 #ifndef PRODUCT
188 // Card Table Count Cache stats
189 double _min_clear_cc_time_ms; // min
190 double _max_clear_cc_time_ms; // max
191 double _cur_clear_cc_time_ms; // clearing time during current pause
192 double _cum_clear_cc_time_ms; // cummulative clearing time
193 jlong _num_cc_clears; // number of times the card count cache has been cleared
194 #endif
196 // These exclude marking times.
197 TruncatedSeq* _recent_gc_times_ms;
199 TruncatedSeq* _concurrent_mark_remark_times_ms;
200 TruncatedSeq* _concurrent_mark_cleanup_times_ms;
202 Summary* _summary;
204 NumberSeq* _all_pause_times_ms;
205 NumberSeq* _all_full_gc_times_ms;
206 double _stop_world_start;
207 NumberSeq* _all_stop_world_times_ms;
208 NumberSeq* _all_yield_times_ms;
210 int _aux_num;
211 NumberSeq* _all_aux_times_ms;
212 double* _cur_aux_start_times_ms;
213 double* _cur_aux_times_ms;
214 bool* _cur_aux_times_set;
216 double* _par_last_gc_worker_start_times_ms;
217 double* _par_last_ext_root_scan_times_ms;
218 double* _par_last_satb_filtering_times_ms;
219 double* _par_last_update_rs_times_ms;
220 double* _par_last_update_rs_processed_buffers;
221 double* _par_last_scan_rs_times_ms;
222 double* _par_last_obj_copy_times_ms;
223 double* _par_last_termination_times_ms;
224 double* _par_last_termination_attempts;
225 double* _par_last_gc_worker_end_times_ms;
226 double* _par_last_gc_worker_times_ms;
228 // Each workers 'other' time i.e. the elapsed time of the parallel
229 // code executed by a worker minus the sum of the individual sub-phase
230 // times for that worker thread.
231 double* _par_last_gc_worker_other_times_ms;
233 // indicates whether we are in young or mixed GC mode
234 bool _gcs_are_young;
236 size_t _young_list_target_length;
237 size_t _young_list_fixed_length;
238 size_t _prev_eden_capacity; // used for logging
240 // The max number of regions we can extend the eden by while the GC
241 // locker is active. This should be >= _young_list_target_length;
242 size_t _young_list_max_length;
244 bool _last_gc_was_young;
246 unsigned _young_pause_num;
247 unsigned _mixed_pause_num;
249 bool _during_marking;
250 bool _in_marking_window;
251 bool _in_marking_window_im;
253 SurvRateGroup* _short_lived_surv_rate_group;
254 SurvRateGroup* _survivor_surv_rate_group;
255 // add here any more surv rate groups
257 double _gc_overhead_perc;
259 double _reserve_factor;
260 size_t _reserve_regions;
262 bool during_marking() {
263 return _during_marking;
264 }
266 private:
267 enum PredictionConstants {
268 TruncatedSeqLength = 10
269 };
271 TruncatedSeq* _alloc_rate_ms_seq;
272 double _prev_collection_pause_end_ms;
274 TruncatedSeq* _pending_card_diff_seq;
275 TruncatedSeq* _rs_length_diff_seq;
276 TruncatedSeq* _cost_per_card_ms_seq;
277 TruncatedSeq* _young_cards_per_entry_ratio_seq;
278 TruncatedSeq* _mixed_cards_per_entry_ratio_seq;
279 TruncatedSeq* _cost_per_entry_ms_seq;
280 TruncatedSeq* _mixed_cost_per_entry_ms_seq;
281 TruncatedSeq* _cost_per_byte_ms_seq;
282 TruncatedSeq* _constant_other_time_ms_seq;
283 TruncatedSeq* _young_other_cost_per_region_ms_seq;
284 TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
286 TruncatedSeq* _pending_cards_seq;
287 TruncatedSeq* _rs_lengths_seq;
289 TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
291 TruncatedSeq* _young_gc_eff_seq;
293 G1YoungGenSizer* _young_gen_sizer;
295 size_t _eden_cset_region_length;
296 size_t _survivor_cset_region_length;
297 size_t _old_cset_region_length;
299 void init_cset_region_lengths(size_t eden_cset_region_length,
300 size_t survivor_cset_region_length);
302 size_t eden_cset_region_length() { return _eden_cset_region_length; }
303 size_t survivor_cset_region_length() { return _survivor_cset_region_length; }
304 size_t old_cset_region_length() { return _old_cset_region_length; }
306 size_t _free_regions_at_end_of_collection;
308 size_t _recorded_rs_lengths;
309 size_t _max_rs_lengths;
311 double _recorded_young_free_cset_time_ms;
312 double _recorded_non_young_free_cset_time_ms;
314 double _sigma;
316 size_t _rs_lengths_prediction;
318 size_t _known_garbage_bytes;
319 double _known_garbage_ratio;
321 double sigma() { return _sigma; }
323 // A function that prevents us putting too much stock in small sample
324 // sets. Returns a number between 2.0 and 1.0, depending on the number
325 // of samples. 5 or more samples yields one; fewer scales linearly from
326 // 2.0 at 1 sample to 1.0 at 5.
327 double confidence_factor(int samples) {
328 if (samples > 4) return 1.0;
329 else return 1.0 + sigma() * ((double)(5 - samples))/2.0;
330 }
332 double get_new_neg_prediction(TruncatedSeq* seq) {
333 return seq->davg() - sigma() * seq->dsd();
334 }
336 #ifndef PRODUCT
337 bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);
338 #endif // PRODUCT
340 void adjust_concurrent_refinement(double update_rs_time,
341 double update_rs_processed_buffers,
342 double goal_ms);
344 uintx no_of_gc_threads() { return _no_of_gc_threads; }
345 void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; }
347 double _pause_time_target_ms;
348 double _recorded_young_cset_choice_time_ms;
349 double _recorded_non_young_cset_choice_time_ms;
350 size_t _pending_cards;
351 size_t _max_pending_cards;
353 public:
354 // Accessors
356 void set_region_eden(HeapRegion* hr, int young_index_in_cset) {
357 hr->set_young();
358 hr->install_surv_rate_group(_short_lived_surv_rate_group);
359 hr->set_young_index_in_cset(young_index_in_cset);
360 }
362 void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {
363 assert(hr->is_young() && hr->is_survivor(), "pre-condition");
364 hr->install_surv_rate_group(_survivor_surv_rate_group);
365 hr->set_young_index_in_cset(young_index_in_cset);
366 }
368 #ifndef PRODUCT
369 bool verify_young_ages();
370 #endif // PRODUCT
372 double get_new_prediction(TruncatedSeq* seq) {
373 return MAX2(seq->davg() + sigma() * seq->dsd(),
374 seq->davg() * confidence_factor(seq->num()));
375 }
377 void record_max_rs_lengths(size_t rs_lengths) {
378 _max_rs_lengths = rs_lengths;
379 }
381 size_t predict_pending_card_diff() {
382 double prediction = get_new_neg_prediction(_pending_card_diff_seq);
383 if (prediction < 0.00001) {
384 return 0;
385 } else {
386 return (size_t) prediction;
387 }
388 }
390 size_t predict_pending_cards() {
391 size_t max_pending_card_num = _g1->max_pending_card_num();
392 size_t diff = predict_pending_card_diff();
393 size_t prediction;
394 if (diff > max_pending_card_num) {
395 prediction = max_pending_card_num;
396 } else {
397 prediction = max_pending_card_num - diff;
398 }
400 return prediction;
401 }
403 size_t predict_rs_length_diff() {
404 return (size_t) get_new_prediction(_rs_length_diff_seq);
405 }
407 double predict_alloc_rate_ms() {
408 return get_new_prediction(_alloc_rate_ms_seq);
409 }
411 double predict_cost_per_card_ms() {
412 return get_new_prediction(_cost_per_card_ms_seq);
413 }
415 double predict_rs_update_time_ms(size_t pending_cards) {
416 return (double) pending_cards * predict_cost_per_card_ms();
417 }
419 double predict_young_cards_per_entry_ratio() {
420 return get_new_prediction(_young_cards_per_entry_ratio_seq);
421 }
423 double predict_mixed_cards_per_entry_ratio() {
424 if (_mixed_cards_per_entry_ratio_seq->num() < 2) {
425 return predict_young_cards_per_entry_ratio();
426 } else {
427 return get_new_prediction(_mixed_cards_per_entry_ratio_seq);
428 }
429 }
431 size_t predict_young_card_num(size_t rs_length) {
432 return (size_t) ((double) rs_length *
433 predict_young_cards_per_entry_ratio());
434 }
436 size_t predict_non_young_card_num(size_t rs_length) {
437 return (size_t) ((double) rs_length *
438 predict_mixed_cards_per_entry_ratio());
439 }
441 double predict_rs_scan_time_ms(size_t card_num) {
442 if (gcs_are_young()) {
443 return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq);
444 } else {
445 return predict_mixed_rs_scan_time_ms(card_num);
446 }
447 }
449 double predict_mixed_rs_scan_time_ms(size_t card_num) {
450 if (_mixed_cost_per_entry_ms_seq->num() < 3) {
451 return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq);
452 } else {
453 return (double) (card_num *
454 get_new_prediction(_mixed_cost_per_entry_ms_seq));
455 }
456 }
458 double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) {
459 if (_cost_per_byte_ms_during_cm_seq->num() < 3) {
460 return (1.1 * (double) bytes_to_copy) *
461 get_new_prediction(_cost_per_byte_ms_seq);
462 } else {
463 return (double) bytes_to_copy *
464 get_new_prediction(_cost_per_byte_ms_during_cm_seq);
465 }
466 }
468 double predict_object_copy_time_ms(size_t bytes_to_copy) {
469 if (_in_marking_window && !_in_marking_window_im) {
470 return predict_object_copy_time_ms_during_cm(bytes_to_copy);
471 } else {
472 return (double) bytes_to_copy *
473 get_new_prediction(_cost_per_byte_ms_seq);
474 }
475 }
477 double predict_constant_other_time_ms() {
478 return get_new_prediction(_constant_other_time_ms_seq);
479 }
481 double predict_young_other_time_ms(size_t young_num) {
482 return (double) young_num *
483 get_new_prediction(_young_other_cost_per_region_ms_seq);
484 }
486 double predict_non_young_other_time_ms(size_t non_young_num) {
487 return (double) non_young_num *
488 get_new_prediction(_non_young_other_cost_per_region_ms_seq);
489 }
491 double predict_base_elapsed_time_ms(size_t pending_cards);
492 double predict_base_elapsed_time_ms(size_t pending_cards,
493 size_t scanned_cards);
494 size_t predict_bytes_to_copy(HeapRegion* hr);
495 double predict_region_elapsed_time_ms(HeapRegion* hr, bool young);
497 void set_recorded_rs_lengths(size_t rs_lengths);
499 size_t cset_region_length() { return young_cset_region_length() +
500 old_cset_region_length(); }
501 size_t young_cset_region_length() { return eden_cset_region_length() +
502 survivor_cset_region_length(); }
504 void record_young_free_cset_time_ms(double time_ms) {
505 _recorded_young_free_cset_time_ms = time_ms;
506 }
508 void record_non_young_free_cset_time_ms(double time_ms) {
509 _recorded_non_young_free_cset_time_ms = time_ms;
510 }
512 double predict_young_gc_eff() {
513 return get_new_neg_prediction(_young_gc_eff_seq);
514 }
516 double predict_survivor_regions_evac_time();
518 void cset_regions_freed() {
519 bool propagate = _last_gc_was_young && !_in_marking_window;
520 _short_lived_surv_rate_group->all_surviving_words_recorded(propagate);
521 _survivor_surv_rate_group->all_surviving_words_recorded(propagate);
522 // also call it on any more surv rate groups
523 }
525 void set_known_garbage_bytes(size_t known_garbage_bytes) {
526 _known_garbage_bytes = known_garbage_bytes;
527 size_t heap_bytes = _g1->capacity();
528 _known_garbage_ratio = (double) _known_garbage_bytes / (double) heap_bytes;
529 }
531 void decrease_known_garbage_bytes(size_t known_garbage_bytes) {
532 guarantee( _known_garbage_bytes >= known_garbage_bytes, "invariant" );
534 _known_garbage_bytes -= known_garbage_bytes;
535 size_t heap_bytes = _g1->capacity();
536 _known_garbage_ratio = (double) _known_garbage_bytes / (double) heap_bytes;
537 }
539 G1MMUTracker* mmu_tracker() {
540 return _mmu_tracker;
541 }
543 double max_pause_time_ms() {
544 return _mmu_tracker->max_gc_time() * 1000.0;
545 }
547 double predict_remark_time_ms() {
548 return get_new_prediction(_concurrent_mark_remark_times_ms);
549 }
551 double predict_cleanup_time_ms() {
552 return get_new_prediction(_concurrent_mark_cleanup_times_ms);
553 }
555 // Returns an estimate of the survival rate of the region at yg-age
556 // "yg_age".
557 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) {
558 TruncatedSeq* seq = surv_rate_group->get_seq(age);
559 if (seq->num() == 0)
560 gclog_or_tty->print("BARF! age is %d", age);
561 guarantee( seq->num() > 0, "invariant" );
562 double pred = get_new_prediction(seq);
563 if (pred > 1.0)
564 pred = 1.0;
565 return pred;
566 }
568 double predict_yg_surv_rate(int age) {
569 return predict_yg_surv_rate(age, _short_lived_surv_rate_group);
570 }
572 double accum_yg_surv_rate_pred(int age) {
573 return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
574 }
576 private:
577 void print_stats(int level, const char* str, double value);
578 void print_stats(int level, const char* str, int value);
580 void print_par_stats(int level, const char* str, double* data);
581 void print_par_sizes(int level, const char* str, double* data);
583 void check_other_times(int level,
584 NumberSeq* other_times_ms,
585 NumberSeq* calc_other_times_ms) const;
587 void print_summary (PauseSummary* stats) const;
589 void print_summary (int level, const char* str, NumberSeq* seq) const;
590 void print_summary_sd (int level, const char* str, NumberSeq* seq) const;
592 double avg_value (double* data);
593 double max_value (double* data);
594 double sum_of_values (double* data);
595 double max_sum (double* data1, double* data2);
597 double _last_pause_time_ms;
599 size_t _bytes_in_collection_set_before_gc;
600 size_t _bytes_copied_during_gc;
602 // Used to count used bytes in CS.
603 friend class CountCSClosure;
605 // Statistics kept per GC stoppage, pause or full.
606 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
608 // Add a new GC of the given duration and end time to the record.
609 void update_recent_gc_times(double end_time_sec, double elapsed_ms);
611 // The head of the list (via "next_in_collection_set()") representing the
612 // current collection set. Set from the incrementally built collection
613 // set at the start of the pause.
614 HeapRegion* _collection_set;
616 // The number of bytes in the collection set before the pause. Set from
617 // the incrementally built collection set at the start of an evacuation
618 // pause.
619 size_t _collection_set_bytes_used_before;
621 // The associated information that is maintained while the incremental
622 // collection set is being built with young regions. Used to populate
623 // the recorded info for the evacuation pause.
625 enum CSetBuildType {
626 Active, // We are actively building the collection set
627 Inactive // We are not actively building the collection set
628 };
630 CSetBuildType _inc_cset_build_state;
632 // The head of the incrementally built collection set.
633 HeapRegion* _inc_cset_head;
635 // The tail of the incrementally built collection set.
636 HeapRegion* _inc_cset_tail;
638 // The number of bytes in the incrementally built collection set.
639 // Used to set _collection_set_bytes_used_before at the start of
640 // an evacuation pause.
641 size_t _inc_cset_bytes_used_before;
643 // Used to record the highest end of heap region in collection set
644 HeapWord* _inc_cset_max_finger;
646 // The RSet lengths recorded for regions in the CSet. It is updated
647 // by the thread that adds a new region to the CSet. We assume that
648 // only one thread can be allocating a new CSet region (currently,
649 // it does so after taking the Heap_lock) hence no need to
650 // synchronize updates to this field.
651 size_t _inc_cset_recorded_rs_lengths;
653 // A concurrent refinement thread periodcially samples the young
654 // region RSets and needs to update _inc_cset_recorded_rs_lengths as
655 // the RSets grow. Instead of having to syncronize updates to that
656 // field we accumulate them in this field and add it to
657 // _inc_cset_recorded_rs_lengths_diffs at the start of a GC.
658 ssize_t _inc_cset_recorded_rs_lengths_diffs;
660 // The predicted elapsed time it will take to collect the regions in
661 // the CSet. This is updated by the thread that adds a new region to
662 // the CSet. See the comment for _inc_cset_recorded_rs_lengths about
663 // MT-safety assumptions.
664 double _inc_cset_predicted_elapsed_time_ms;
666 // See the comment for _inc_cset_recorded_rs_lengths_diffs.
667 double _inc_cset_predicted_elapsed_time_ms_diffs;
669 // Stash a pointer to the g1 heap.
670 G1CollectedHeap* _g1;
672 // The ratio of gc time to elapsed time, computed over recent pauses.
673 double _recent_avg_pause_time_ratio;
675 double recent_avg_pause_time_ratio() {
676 return _recent_avg_pause_time_ratio;
677 }
679 // At the end of a pause we check the heap occupancy and we decide
680 // whether we will start a marking cycle during the next pause. If
681 // we decide that we want to do that, we will set this parameter to
682 // true. So, this parameter will stay true between the end of a
683 // pause and the beginning of a subsequent pause (not necessarily
684 // the next one, see the comments on the next field) when we decide
685 // that we will indeed start a marking cycle and do the initial-mark
686 // work.
687 volatile bool _initiate_conc_mark_if_possible;
689 // If initiate_conc_mark_if_possible() is set at the beginning of a
690 // pause, it is a suggestion that the pause should start a marking
691 // cycle by doing the initial-mark work. However, it is possible
692 // that the concurrent marking thread is still finishing up the
693 // previous marking cycle (e.g., clearing the next marking
694 // bitmap). If that is the case we cannot start a new cycle and
695 // we'll have to wait for the concurrent marking thread to finish
696 // what it is doing. In this case we will postpone the marking cycle
697 // initiation decision for the next pause. When we eventually decide
698 // to start a cycle, we will set _during_initial_mark_pause which
699 // will stay true until the end of the initial-mark pause and it's
700 // the condition that indicates that a pause is doing the
701 // initial-mark work.
702 volatile bool _during_initial_mark_pause;
704 bool _last_young_gc;
706 // This set of variables tracks the collector efficiency, in order to
707 // determine whether we should initiate a new marking.
708 double _cur_mark_stop_world_time_ms;
709 double _mark_remark_start_sec;
710 double _mark_cleanup_start_sec;
711 double _root_region_scan_wait_time_ms;
713 // Update the young list target length either by setting it to the
714 // desired fixed value or by calculating it using G1's pause
715 // prediction model. If no rs_lengths parameter is passed, predict
716 // the RS lengths using the prediction model, otherwise use the
717 // given rs_lengths as the prediction.
718 void update_young_list_target_length(size_t rs_lengths = (size_t) -1);
720 // Calculate and return the minimum desired young list target
721 // length. This is the minimum desired young list length according
722 // to the user's inputs.
723 size_t calculate_young_list_desired_min_length(size_t base_min_length);
725 // Calculate and return the maximum desired young list target
726 // length. This is the maximum desired young list length according
727 // to the user's inputs.
728 size_t calculate_young_list_desired_max_length();
730 // Calculate and return the maximum young list target length that
731 // can fit into the pause time goal. The parameters are: rs_lengths
732 // represent the prediction of how large the young RSet lengths will
733 // be, base_min_length is the alreay existing number of regions in
734 // the young list, min_length and max_length are the desired min and
735 // max young list length according to the user's inputs.
736 size_t calculate_young_list_target_length(size_t rs_lengths,
737 size_t base_min_length,
738 size_t desired_min_length,
739 size_t desired_max_length);
741 // Check whether a given young length (young_length) fits into the
742 // given target pause time and whether the prediction for the amount
743 // of objects to be copied for the given length will fit into the
744 // given free space (expressed by base_free_regions). It is used by
745 // calculate_young_list_target_length().
746 bool predict_will_fit(size_t young_length, double base_time_ms,
747 size_t base_free_regions, double target_pause_time_ms);
749 // Count the number of bytes used in the CS.
750 void count_CS_bytes_used();
752 public:
754 G1CollectorPolicy();
756 virtual G1CollectorPolicy* as_g1_policy() { return this; }
758 virtual CollectorPolicy::Name kind() {
759 return CollectorPolicy::G1CollectorPolicyKind;
760 }
762 // Check the current value of the young list RSet lengths and
763 // compare it against the last prediction. If the current value is
764 // higher, recalculate the young list target length prediction.
765 void revise_young_list_target_length_if_necessary();
767 size_t bytes_in_collection_set() {
768 return _bytes_in_collection_set_before_gc;
769 }
771 unsigned calc_gc_alloc_time_stamp() {
772 return _all_pause_times_ms->num() + 1;
773 }
775 // This should be called after the heap is resized.
776 void record_new_heap_size(size_t new_number_of_regions);
778 void init();
780 // Create jstat counters for the policy.
781 virtual void initialize_gc_policy_counters();
783 virtual HeapWord* mem_allocate_work(size_t size,
784 bool is_tlab,
785 bool* gc_overhead_limit_was_exceeded);
787 // This method controls how a collector handles one or more
788 // of its generations being fully allocated.
789 virtual HeapWord* satisfy_failed_allocation(size_t size,
790 bool is_tlab);
792 BarrierSet::Name barrier_set_name() { return BarrierSet::G1SATBCTLogging; }
794 GenRemSet::Name rem_set_name() { return GenRemSet::CardTable; }
796 bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
798 // Update the heuristic info to record a collection pause of the given
799 // start time, where the given number of bytes were used at the start.
800 // This may involve changing the desired size of a collection set.
802 void record_stop_world_start();
804 void record_collection_pause_start(double start_time_sec, size_t start_used);
806 // Must currently be called while the world is stopped.
807 void record_concurrent_mark_init_end(double
808 mark_init_elapsed_time_ms);
810 void record_root_region_scan_wait_time(double time_ms) {
811 _root_region_scan_wait_time_ms = time_ms;
812 }
814 void record_concurrent_mark_remark_start();
815 void record_concurrent_mark_remark_end();
817 void record_concurrent_mark_cleanup_start();
818 void record_concurrent_mark_cleanup_end(int no_of_gc_threads);
819 void record_concurrent_mark_cleanup_completed();
821 void record_concurrent_pause();
822 void record_concurrent_pause_end();
824 void record_collection_pause_end(int no_of_gc_threads);
825 void print_heap_transition();
827 // Record the fact that a full collection occurred.
828 void record_full_collection_start();
829 void record_full_collection_end();
831 void record_gc_worker_start_time(int worker_i, double ms) {
832 _par_last_gc_worker_start_times_ms[worker_i] = ms;
833 }
835 void record_ext_root_scan_time(int worker_i, double ms) {
836 _par_last_ext_root_scan_times_ms[worker_i] = ms;
837 }
839 void record_satb_filtering_time(int worker_i, double ms) {
840 _par_last_satb_filtering_times_ms[worker_i] = ms;
841 }
843 void record_update_rs_time(int thread, double ms) {
844 _par_last_update_rs_times_ms[thread] = ms;
845 }
847 void record_update_rs_processed_buffers (int thread,
848 double processed_buffers) {
849 _par_last_update_rs_processed_buffers[thread] = processed_buffers;
850 }
852 void record_scan_rs_time(int thread, double ms) {
853 _par_last_scan_rs_times_ms[thread] = ms;
854 }
856 void reset_obj_copy_time(int thread) {
857 _par_last_obj_copy_times_ms[thread] = 0.0;
858 }
860 void reset_obj_copy_time() {
861 reset_obj_copy_time(0);
862 }
864 void record_obj_copy_time(int thread, double ms) {
865 _par_last_obj_copy_times_ms[thread] += ms;
866 }
868 void record_termination(int thread, double ms, size_t attempts) {
869 _par_last_termination_times_ms[thread] = ms;
870 _par_last_termination_attempts[thread] = (double) attempts;
871 }
873 void record_gc_worker_end_time(int worker_i, double ms) {
874 _par_last_gc_worker_end_times_ms[worker_i] = ms;
875 }
877 void record_pause_time_ms(double ms) {
878 _last_pause_time_ms = ms;
879 }
881 void record_clear_ct_time(double ms) {
882 _cur_clear_ct_time_ms = ms;
883 }
885 void record_par_time(double ms) {
886 _cur_collection_par_time_ms = ms;
887 }
889 void record_code_root_fixup_time(double ms) {
890 _cur_collection_code_root_fixup_time_ms = ms;
891 }
893 void record_aux_start_time(int i) {
894 guarantee(i < _aux_num, "should be within range");
895 _cur_aux_start_times_ms[i] = os::elapsedTime() * 1000.0;
896 }
898 void record_aux_end_time(int i) {
899 guarantee(i < _aux_num, "should be within range");
900 double ms = os::elapsedTime() * 1000.0 - _cur_aux_start_times_ms[i];
901 _cur_aux_times_set[i] = true;
902 _cur_aux_times_ms[i] += ms;
903 }
905 void record_ref_proc_time(double ms) {
906 _cur_ref_proc_time_ms = ms;
907 }
909 void record_ref_enq_time(double ms) {
910 _cur_ref_enq_time_ms = ms;
911 }
913 #ifndef PRODUCT
914 void record_cc_clear_time(double ms) {
915 if (_min_clear_cc_time_ms < 0.0 || ms <= _min_clear_cc_time_ms)
916 _min_clear_cc_time_ms = ms;
917 if (_max_clear_cc_time_ms < 0.0 || ms >= _max_clear_cc_time_ms)
918 _max_clear_cc_time_ms = ms;
919 _cur_clear_cc_time_ms = ms;
920 _cum_clear_cc_time_ms += ms;
921 _num_cc_clears++;
922 }
923 #endif
925 // Record how much space we copied during a GC. This is typically
926 // called when a GC alloc region is being retired.
927 void record_bytes_copied_during_gc(size_t bytes) {
928 _bytes_copied_during_gc += bytes;
929 }
931 // The amount of space we copied during a GC.
932 size_t bytes_copied_during_gc() {
933 return _bytes_copied_during_gc;
934 }
936 // Determine whether there are candidate regions so that the
937 // next GC should be mixed. The two action strings are used
938 // in the ergo output when the method returns true or false.
939 bool next_gc_should_be_mixed(const char* true_action_str,
940 const char* false_action_str);
942 // Choose a new collection set. Marks the chosen regions as being
943 // "in_collection_set", and links them together. The head and number of
944 // the collection set are available via access methods.
945 void finalize_cset(double target_pause_time_ms);
947 // The head of the list (via "next_in_collection_set()") representing the
948 // current collection set.
949 HeapRegion* collection_set() { return _collection_set; }
951 void clear_collection_set() { _collection_set = NULL; }
953 // Add old region "hr" to the CSet.
954 void add_old_region_to_cset(HeapRegion* hr);
956 // Incremental CSet Support
958 // The head of the incrementally built collection set.
959 HeapRegion* inc_cset_head() { return _inc_cset_head; }
961 // The tail of the incrementally built collection set.
962 HeapRegion* inc_set_tail() { return _inc_cset_tail; }
964 // Initialize incremental collection set info.
965 void start_incremental_cset_building();
967 // Perform any final calculations on the incremental CSet fields
968 // before we can use them.
969 void finalize_incremental_cset_building();
971 void clear_incremental_cset() {
972 _inc_cset_head = NULL;
973 _inc_cset_tail = NULL;
974 }
976 // Stop adding regions to the incremental collection set
977 void stop_incremental_cset_building() { _inc_cset_build_state = Inactive; }
979 // Add information about hr to the aggregated information for the
980 // incrementally built collection set.
981 void add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length);
983 // Update information about hr in the aggregated information for
984 // the incrementally built collection set.
985 void update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length);
987 private:
988 // Update the incremental cset information when adding a region
989 // (should not be called directly).
990 void add_region_to_incremental_cset_common(HeapRegion* hr);
992 public:
993 // Add hr to the LHS of the incremental collection set.
994 void add_region_to_incremental_cset_lhs(HeapRegion* hr);
996 // Add hr to the RHS of the incremental collection set.
997 void add_region_to_incremental_cset_rhs(HeapRegion* hr);
999 #ifndef PRODUCT
1000 void print_collection_set(HeapRegion* list_head, outputStream* st);
1001 #endif // !PRODUCT
1003 bool initiate_conc_mark_if_possible() { return _initiate_conc_mark_if_possible; }
1004 void set_initiate_conc_mark_if_possible() { _initiate_conc_mark_if_possible = true; }
1005 void clear_initiate_conc_mark_if_possible() { _initiate_conc_mark_if_possible = false; }
1007 bool during_initial_mark_pause() { return _during_initial_mark_pause; }
1008 void set_during_initial_mark_pause() { _during_initial_mark_pause = true; }
1009 void clear_during_initial_mark_pause(){ _during_initial_mark_pause = false; }
1011 // This sets the initiate_conc_mark_if_possible() flag to start a
1012 // new cycle, as long as we are not already in one. It's best if it
1013 // is called during a safepoint when the test whether a cycle is in
1014 // progress or not is stable.
1015 bool force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause);
1017 // This is called at the very beginning of an evacuation pause (it
1018 // has to be the first thing that the pause does). If
1019 // initiate_conc_mark_if_possible() is true, and the concurrent
1020 // marking thread has completed its work during the previous cycle,
1021 // it will set during_initial_mark_pause() to so that the pause does
1022 // the initial-mark work and start a marking cycle.
1023 void decide_on_conc_mark_initiation();
1025 // If an expansion would be appropriate, because recent GC overhead had
1026 // exceeded the desired limit, return an amount to expand by.
1027 size_t expansion_amount();
1029 #ifndef PRODUCT
1030 // Check any appropriate marked bytes info, asserting false if
1031 // something's wrong, else returning "true".
1032 bool assertMarkedBytesDataOK();
1033 #endif
1035 // Print tracing information.
1036 void print_tracing_info() const;
1038 // Print stats on young survival ratio
1039 void print_yg_surv_rate_info() const;
1041 void finished_recalculating_age_indexes(bool is_survivors) {
1042 if (is_survivors) {
1043 _survivor_surv_rate_group->finished_recalculating_age_indexes();
1044 } else {
1045 _short_lived_surv_rate_group->finished_recalculating_age_indexes();
1046 }
1047 // do that for any other surv rate groups
1048 }
1050 bool is_young_list_full() {
1051 size_t young_list_length = _g1->young_list()->length();
1052 size_t young_list_target_length = _young_list_target_length;
1053 return young_list_length >= young_list_target_length;
1054 }
1056 bool can_expand_young_list() {
1057 size_t young_list_length = _g1->young_list()->length();
1058 size_t young_list_max_length = _young_list_max_length;
1059 return young_list_length < young_list_max_length;
1060 }
1062 size_t young_list_max_length() {
1063 return _young_list_max_length;
1064 }
1066 bool gcs_are_young() {
1067 return _gcs_are_young;
1068 }
1069 void set_gcs_are_young(bool gcs_are_young) {
1070 _gcs_are_young = gcs_are_young;
1071 }
1073 bool adaptive_young_list_length() {
1074 return _young_gen_sizer->adaptive_young_list_length();
1075 }
1077 inline double get_gc_eff_factor() {
1078 double ratio = _known_garbage_ratio;
1080 double square = ratio * ratio;
1081 // square = square * square;
1082 double ret = square * 9.0 + 1.0;
1083 #if 0
1084 gclog_or_tty->print_cr("ratio = %1.2lf, ret = %1.2lf", ratio, ret);
1085 #endif // 0
1086 guarantee(0.0 <= ret && ret < 10.0, "invariant!");
1087 return ret;
1088 }
1090 private:
1091 //
1092 // Survivor regions policy.
1093 //
1095 // Current tenuring threshold, set to 0 if the collector reaches the
1096 // maximum amount of suvivors regions.
1097 int _tenuring_threshold;
1099 // The limit on the number of regions allocated for survivors.
1100 size_t _max_survivor_regions;
1102 // For reporting purposes.
1103 size_t _eden_bytes_before_gc;
1104 size_t _survivor_bytes_before_gc;
1105 size_t _capacity_before_gc;
1107 // The amount of survor regions after a collection.
1108 size_t _recorded_survivor_regions;
1109 // List of survivor regions.
1110 HeapRegion* _recorded_survivor_head;
1111 HeapRegion* _recorded_survivor_tail;
1113 ageTable _survivors_age_table;
1115 public:
1117 inline GCAllocPurpose
1118 evacuation_destination(HeapRegion* src_region, int age, size_t word_sz) {
1119 if (age < _tenuring_threshold && src_region->is_young()) {
1120 return GCAllocForSurvived;
1121 } else {
1122 return GCAllocForTenured;
1123 }
1124 }
1126 inline bool track_object_age(GCAllocPurpose purpose) {
1127 return purpose == GCAllocForSurvived;
1128 }
1130 static const size_t REGIONS_UNLIMITED = ~(size_t)0;
1132 size_t max_regions(int purpose);
1134 // The limit on regions for a particular purpose is reached.
1135 void note_alloc_region_limit_reached(int purpose) {
1136 if (purpose == GCAllocForSurvived) {
1137 _tenuring_threshold = 0;
1138 }
1139 }
1141 void note_start_adding_survivor_regions() {
1142 _survivor_surv_rate_group->start_adding_regions();
1143 }
1145 void note_stop_adding_survivor_regions() {
1146 _survivor_surv_rate_group->stop_adding_regions();
1147 }
1149 void record_survivor_regions(size_t regions,
1150 HeapRegion* head,
1151 HeapRegion* tail) {
1152 _recorded_survivor_regions = regions;
1153 _recorded_survivor_head = head;
1154 _recorded_survivor_tail = tail;
1155 }
1157 size_t recorded_survivor_regions() {
1158 return _recorded_survivor_regions;
1159 }
1161 void record_thread_age_table(ageTable* age_table)
1162 {
1163 _survivors_age_table.merge_par(age_table);
1164 }
1166 void update_max_gc_locker_expansion();
1168 // Calculates survivor space parameters.
1169 void update_survivors_policy();
1171 };
1173 // This should move to some place more general...
1175 // If we have "n" measurements, and we've kept track of their "sum" and the
1176 // "sum_of_squares" of the measurements, this returns the variance of the
1177 // sequence.
1178 inline double variance(int n, double sum_of_squares, double sum) {
1179 double n_d = (double)n;
1180 double avg = sum/n_d;
1181 return (sum_of_squares - 2.0 * avg * sum + n_d * avg * avg) / n_d;
1182 }
1184 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTORPOLICY_HPP