1 /*
2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/concurrentG1Refine.hpp"
27 #include "gc_implementation/g1/concurrentMark.hpp"
28 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
30 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
31 #include "gc_implementation/g1/g1ErgoVerbose.hpp"
32 #include "gc_implementation/g1/heapRegionRemSet.hpp"
33 #include "gc_implementation/shared/gcPolicyCounters.hpp"
34 #include "runtime/arguments.hpp"
35 #include "runtime/java.hpp"
36 #include "runtime/mutexLocker.hpp"
37 #include "utilities/debug.hpp"
38
39 #define PREDICTIONS_VERBOSE 0
40
41 // <NEW PREDICTION>
42
43 // Different defaults for different number of GC threads
44 // They were chosen by running GCOld and SPECjbb on debris with different
45 // numbers of GC threads and choosing them based on the results
46
47 // all the same
48 static double rs_length_diff_defaults[] = {
49 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
50 };
51
52 static double cost_per_card_ms_defaults[] = {
53 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
54 };
55
56 // all the same
57 static double fully_young_cards_per_entry_ratio_defaults[] = {
58 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
59 };
60
61 static double cost_per_entry_ms_defaults[] = {
62 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
63 };
64
65 static double cost_per_byte_ms_defaults[] = {
66 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
67 };
68
69 // these should be pretty consistent
70 static double constant_other_time_ms_defaults[] = {
71 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
72 };
73
74
75 static double young_other_cost_per_region_ms_defaults[] = {
76 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
77 };
78
79 static double non_young_other_cost_per_region_ms_defaults[] = {
80 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
81 };
82
83 // </NEW PREDICTION>
84
85 // Help class for avoiding interleaved logging
86 class LineBuffer: public StackObj {
87
88 private:
89 static const int BUFFER_LEN = 1024;
90 static const int INDENT_CHARS = 3;
91 char _buffer[BUFFER_LEN];
92 int _indent_level;
93 int _cur;
94
95 void vappend(const char* format, va_list ap) {
96 int res = vsnprintf(&_buffer[_cur], BUFFER_LEN - _cur, format, ap);
97 if (res != -1) {
98 _cur += res;
99 } else {
100 DEBUG_ONLY(warning("buffer too small in LineBuffer");)
101 _buffer[BUFFER_LEN -1] = 0;
102 _cur = BUFFER_LEN; // vsnprintf above should not add to _buffer if we are called again
103 }
104 }
105
106 public:
107 explicit LineBuffer(int indent_level): _indent_level(indent_level), _cur(0) {
108 for (; (_cur < BUFFER_LEN && _cur < (_indent_level * INDENT_CHARS)); _cur++) {
109 _buffer[_cur] = ' ';
110 }
111 }
112
113 #ifndef PRODUCT
114 ~LineBuffer() {
115 assert(_cur == _indent_level * INDENT_CHARS, "pending data in buffer - append_and_print_cr() not called?");
116 }
117 #endif
118
119 void append(const char* format, ...) {
120 va_list ap;
121 va_start(ap, format);
122 vappend(format, ap);
123 va_end(ap);
124 }
125
126 void append_and_print_cr(const char* format, ...) {
127 va_list ap;
128 va_start(ap, format);
129 vappend(format, ap);
130 va_end(ap);
131 gclog_or_tty->print_cr("%s", _buffer);
132 _cur = _indent_level * INDENT_CHARS;
133 }
134 };
135
136 G1CollectorPolicy::G1CollectorPolicy() :
137 _parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads()
138 ? ParallelGCThreads : 1),
139
140 _n_pauses(0),
141 _recent_rs_scan_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
142 _recent_pause_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
143 _recent_rs_sizes(new TruncatedSeq(NumPrevPausesForHeuristics)),
144 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
145 _all_pause_times_ms(new NumberSeq()),
146 _stop_world_start(0.0),
147 _all_stop_world_times_ms(new NumberSeq()),
148 _all_yield_times_ms(new NumberSeq()),
149 _using_new_ratio_calculations(false),
150
151 _all_mod_union_times_ms(new NumberSeq()),
152
153 _summary(new Summary()),
154
155 _cur_clear_ct_time_ms(0.0),
156
157 _cur_ref_proc_time_ms(0.0),
158 _cur_ref_enq_time_ms(0.0),
159
160 #ifndef PRODUCT
161 _min_clear_cc_time_ms(-1.0),
162 _max_clear_cc_time_ms(-1.0),
163 _cur_clear_cc_time_ms(0.0),
164 _cum_clear_cc_time_ms(0.0),
165 _num_cc_clears(0L),
166 #endif
167
168 _region_num_young(0),
169 _region_num_tenured(0),
170 _prev_region_num_young(0),
171 _prev_region_num_tenured(0),
172
173 _aux_num(10),
174 _all_aux_times_ms(new NumberSeq[_aux_num]),
175 _cur_aux_start_times_ms(new double[_aux_num]),
176 _cur_aux_times_ms(new double[_aux_num]),
177 _cur_aux_times_set(new bool[_aux_num]),
178
179 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
180 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
181
182 // <NEW PREDICTION>
183
184 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
185 _prev_collection_pause_end_ms(0.0),
186 _pending_card_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
187 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
188 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
189 _fully_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
190 _partially_young_cards_per_entry_ratio_seq(
191 new TruncatedSeq(TruncatedSeqLength)),
192 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
193 _partially_young_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
194 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
195 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
196 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
197 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
198 _non_young_other_cost_per_region_ms_seq(
199 new TruncatedSeq(TruncatedSeqLength)),
200
201 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
202 _scanned_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
203 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
204
205 _pause_time_target_ms((double) MaxGCPauseMillis),
206
207 // </NEW PREDICTION>
208
209 _full_young_gcs(true),
210 _full_young_pause_num(0),
211 _partial_young_pause_num(0),
212
213 _during_marking(false),
214 _in_marking_window(false),
215 _in_marking_window_im(false),
216
217 _known_garbage_ratio(0.0),
218 _known_garbage_bytes(0),
219
220 _young_gc_eff_seq(new TruncatedSeq(TruncatedSeqLength)),
221
222 _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
223
224 _recent_CS_bytes_used_before(new TruncatedSeq(NumPrevPausesForHeuristics)),
225 _recent_CS_bytes_surviving(new TruncatedSeq(NumPrevPausesForHeuristics)),
226
227 _recent_avg_pause_time_ratio(0.0),
228 _num_markings(0),
229 _n_marks(0),
230 _n_pauses_at_mark_end(0),
231
232 _all_full_gc_times_ms(new NumberSeq()),
233
234 // G1PausesBtwnConcMark defaults to -1
235 // so the hack is to do the cast QQQ FIXME
236 _pauses_btwn_concurrent_mark((size_t)G1PausesBtwnConcMark),
237 _n_marks_since_last_pause(0),
238 _initiate_conc_mark_if_possible(false),
239 _during_initial_mark_pause(false),
240 _should_revert_to_full_young_gcs(false),
241 _last_full_young_gc(false),
242
243 _eden_bytes_before_gc(0),
244 _survivor_bytes_before_gc(0),
245 _capacity_before_gc(0),
246
247 _prev_collection_pause_used_at_end_bytes(0),
248
249 _collection_set(NULL),
250 _collection_set_size(0),
251 _collection_set_bytes_used_before(0),
252
253 // Incremental CSet attributes
254 _inc_cset_build_state(Inactive),
255 _inc_cset_head(NULL),
256 _inc_cset_tail(NULL),
257 _inc_cset_size(0),
258 _inc_cset_young_index(0),
259 _inc_cset_bytes_used_before(0),
260 _inc_cset_max_finger(NULL),
261 _inc_cset_recorded_young_bytes(0),
262 _inc_cset_recorded_rs_lengths(0),
263 _inc_cset_predicted_elapsed_time_ms(0.0),
264 _inc_cset_predicted_bytes_to_copy(0),
265
266 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
267 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
268 #endif // _MSC_VER
269
270 _short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
271 G1YoungSurvRateNumRegionsSummary)),
272 _survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
273 G1YoungSurvRateNumRegionsSummary)),
274 // add here any more surv rate groups
275 _recorded_survivor_regions(0),
276 _recorded_survivor_head(NULL),
277 _recorded_survivor_tail(NULL),
278 _survivors_age_table(true),
279
280 _gc_overhead_perc(0.0) {
281
282 // Set up the region size and associated fields. Given that the
283 // policy is created before the heap, we have to set this up here,
284 // so it's done as soon as possible.
285 HeapRegion::setup_heap_region_size(Arguments::min_heap_size());
286 HeapRegionRemSet::setup_remset_size();
287
288 G1ErgoVerbose::initialize();
289 if (PrintAdaptiveSizePolicy) {
290 // Currently, we only use a single switch for all the heuristics.
291 G1ErgoVerbose::set_enabled(true);
292 // Given that we don't currently have a verboseness level
293 // parameter, we'll hardcode this to high. This can be easily
294 // changed in the future.
295 G1ErgoVerbose::set_level(ErgoHigh);
296 } else {
297 G1ErgoVerbose::set_enabled(false);
298 }
299
300 // Verify PLAB sizes
301 const uint region_size = HeapRegion::GrainWords;
302 if (YoungPLABSize > region_size || OldPLABSize > region_size) {
303 char buffer[128];
304 jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most %u",
305 OldPLABSize > region_size ? "Old" : "Young", region_size);
306 vm_exit_during_initialization(buffer);
307 }
308
309 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
310 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
311
312 _par_last_gc_worker_start_times_ms = new double[_parallel_gc_threads];
313 _par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
314 _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
315
316 _par_last_update_rs_times_ms = new double[_parallel_gc_threads];
317 _par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
318
319 _par_last_scan_rs_times_ms = new double[_parallel_gc_threads];
320
321 _par_last_obj_copy_times_ms = new double[_parallel_gc_threads];
322
323 _par_last_termination_times_ms = new double[_parallel_gc_threads];
324 _par_last_termination_attempts = new double[_parallel_gc_threads];
325 _par_last_gc_worker_end_times_ms = new double[_parallel_gc_threads];
326 _par_last_gc_worker_times_ms = new double[_parallel_gc_threads];
327
328 // start conservatively
329 _expensive_region_limit_ms = 0.5 * (double) MaxGCPauseMillis;
330
331 // <NEW PREDICTION>
332
333 int index;
334 if (ParallelGCThreads == 0)
335 index = 0;
336 else if (ParallelGCThreads > 8)
337 index = 7;
338 else
339 index = ParallelGCThreads - 1;
340
341 _pending_card_diff_seq->add(0.0);
342 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
343 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
344 _fully_young_cards_per_entry_ratio_seq->add(
345 fully_young_cards_per_entry_ratio_defaults[index]);
346 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
347 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
348 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
349 _young_other_cost_per_region_ms_seq->add(
350 young_other_cost_per_region_ms_defaults[index]);
351 _non_young_other_cost_per_region_ms_seq->add(
352 non_young_other_cost_per_region_ms_defaults[index]);
353
354 // </NEW PREDICTION>
355
356 // Below, we might need to calculate the pause time target based on
357 // the pause interval. When we do so we are going to give G1 maximum
358 // flexibility and allow it to do pauses when it needs to. So, we'll
359 // arrange that the pause interval to be pause time target + 1 to
360 // ensure that a) the pause time target is maximized with respect to
361 // the pause interval and b) we maintain the invariant that pause
362 // time target < pause interval. If the user does not want this
363 // maximum flexibility, they will have to set the pause interval
364 // explicitly.
365
366 // First make sure that, if either parameter is set, its value is
367 // reasonable.
368 if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
369 if (MaxGCPauseMillis < 1) {
370 vm_exit_during_initialization("MaxGCPauseMillis should be "
371 "greater than 0");
372 }
373 }
374 if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
375 if (GCPauseIntervalMillis < 1) {
376 vm_exit_during_initialization("GCPauseIntervalMillis should be "
377 "greater than 0");
378 }
379 }
380
381 // Then, if the pause time target parameter was not set, set it to
382 // the default value.
383 if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
384 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
385 // The default pause time target in G1 is 200ms
386 FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
387 } else {
388 // We do not allow the pause interval to be set without the
389 // pause time target
390 vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
391 "without setting MaxGCPauseMillis");
392 }
393 }
394
395 // Then, if the interval parameter was not set, set it according to
396 // the pause time target (this will also deal with the case when the
397 // pause time target is the default value).
398 if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
399 FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
400 }
401
402 // Finally, make sure that the two parameters are consistent.
403 if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
404 char buffer[256];
405 jio_snprintf(buffer, 256,
406 "MaxGCPauseMillis (%u) should be less than "
407 "GCPauseIntervalMillis (%u)",
408 MaxGCPauseMillis, GCPauseIntervalMillis);
409 vm_exit_during_initialization(buffer);
410 }
411
412 double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
413 double time_slice = (double) GCPauseIntervalMillis / 1000.0;
414 _mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
415 _sigma = (double) G1ConfidencePercent / 100.0;
416
417 // start conservatively (around 50ms is about right)
418 _concurrent_mark_remark_times_ms->add(0.05);
419 _concurrent_mark_cleanup_times_ms->add(0.20);
420 _tenuring_threshold = MaxTenuringThreshold;
421 // _max_survivor_regions will be calculated by
422 // update_young_list_target_length() during initialization.
423 _max_survivor_regions = 0;
424
425 assert(GCTimeRatio > 0,
426 "we should have set it to a default value set_g1_gc_flags() "
427 "if a user set it to 0");
428 _gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
429
430 uintx reserve_perc = G1ReservePercent;
431 // Put an artificial ceiling on this so that it's not set to a silly value.
432 if (reserve_perc > 50) {
433 reserve_perc = 50;
434 warning("G1ReservePercent is set to a value that is too large, "
435 "it's been updated to %u", reserve_perc);
436 }
437 _reserve_factor = (double) reserve_perc / 100.0;
438 // This will be set when the heap is expanded
439 // for the first time during initialization.
440 _reserve_regions = 0;
441
442 initialize_all();
443 }
444
445 // Increment "i", mod "len"
446 static void inc_mod(int& i, int len) {
447 i++; if (i == len) i = 0;
448 }
449
450 void G1CollectorPolicy::initialize_flags() {
451 set_min_alignment(HeapRegion::GrainBytes);
452 set_max_alignment(GenRemSet::max_alignment_constraint(rem_set_name()));
453 if (SurvivorRatio < 1) {
454 vm_exit_during_initialization("Invalid survivor ratio specified");
455 }
456 CollectorPolicy::initialize_flags();
457 }
458
459 // The easiest way to deal with the parsing of the NewSize /
460 // MaxNewSize / etc. parameteres is to re-use the code in the
461 // TwoGenerationCollectorPolicy class. This is similar to what
462 // ParallelScavenge does with its GenerationSizer class (see
463 // ParallelScavengeHeap::initialize()). We might change this in the
464 // future, but it's a good start.
465 class G1YoungGenSizer : public TwoGenerationCollectorPolicy {
466
467 public:
468 G1YoungGenSizer() {
469 initialize_flags();
470 initialize_size_info();
471 }
472 size_t size_to_region_num(size_t byte_size) {
473 return MAX2((size_t) 1, byte_size / HeapRegion::GrainBytes);
474 }
475 size_t min_young_region_num() {
476 return size_to_region_num(_min_gen0_size);
477 }
478 size_t initial_young_region_num() {
479 return size_to_region_num(_initial_gen0_size);
480 }
481 size_t max_young_region_num() {
482 return size_to_region_num(_max_gen0_size);
483 }
484 };
485
486 void G1CollectorPolicy::update_young_list_size_using_newratio(size_t number_of_heap_regions) {
487 assert(number_of_heap_regions > 0, "Heap must be initialized");
488 size_t young_size = number_of_heap_regions / (NewRatio + 1);
489 _min_desired_young_length = young_size;
490 _max_desired_young_length = young_size;
491 }
492
493 void G1CollectorPolicy::init() {
494 // Set aside an initial future to_space.
495 _g1 = G1CollectedHeap::heap();
496
497 assert(Heap_lock->owned_by_self(), "Locking discipline.");
498
499 initialize_gc_policy_counters();
500
501 G1YoungGenSizer sizer;
502 size_t initial_region_num = sizer.initial_young_region_num();
503 _min_desired_young_length = sizer.min_young_region_num();
504 _max_desired_young_length = sizer.max_young_region_num();
505
506 if (FLAG_IS_CMDLINE(NewRatio)) {
507 if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
508 gclog_or_tty->print_cr("-XX:NewSize and -XX:MaxNewSize overrides -XX:NewRatio");
509 } else {
510 // Treat NewRatio as a fixed size that is only recalculated when the heap size changes
511 size_t heap_regions = sizer.size_to_region_num(_g1->n_regions());
512 update_young_list_size_using_newratio(heap_regions);
513 _using_new_ratio_calculations = true;
514 }
515 }
516
517 // GenCollectorPolicy guarantees that min <= initial <= max.
518 // Asserting here just to state that we rely on this property.
519 assert(_min_desired_young_length <= _max_desired_young_length, "Invalid min/max young gen size values");
520 assert(initial_region_num <= _max_desired_young_length, "Initial young gen size too large");
521 assert(_min_desired_young_length <= initial_region_num, "Initial young gen size too small");
522
523 set_adaptive_young_list_length(_min_desired_young_length < _max_desired_young_length);
524 if (adaptive_young_list_length()) {
525 _young_list_fixed_length = 0;
526 } else {
527 _young_list_fixed_length = initial_region_num;
528 }
529 _free_regions_at_end_of_collection = _g1->free_regions();
530 update_young_list_target_length();
531 _prev_eden_capacity = _young_list_target_length * HeapRegion::GrainBytes;
532
533 // We may immediately start allocating regions and placing them on the
534 // collection set list. Initialize the per-collection set info
535 start_incremental_cset_building();
536 }
537
538 // Create the jstat counters for the policy.
539 void G1CollectorPolicy::initialize_gc_policy_counters() {
540 _gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
541 }
542
543 bool G1CollectorPolicy::predict_will_fit(size_t young_length,
544 double base_time_ms,
545 size_t base_free_regions,
546 double target_pause_time_ms) {
547 if (young_length >= base_free_regions) {
548 // end condition 1: not enough space for the young regions
549 return false;
550 }
551
552 double accum_surv_rate = accum_yg_surv_rate_pred((int)(young_length - 1));
553 size_t bytes_to_copy =
554 (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
555 double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
556 double young_other_time_ms = predict_young_other_time_ms(young_length);
557 double pause_time_ms = base_time_ms + copy_time_ms + young_other_time_ms;
558 if (pause_time_ms > target_pause_time_ms) {
559 // end condition 2: prediction is over the target pause time
560 return false;
561 }
562
563 size_t free_bytes =
564 (base_free_regions - young_length) * HeapRegion::GrainBytes;
565 if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
566 // end condition 3: out-of-space (conservatively!)
567 return false;
568 }
569
570 // success!
571 return true;
572 }
573
574 void G1CollectorPolicy::record_new_heap_size(size_t new_number_of_regions) {
575 // re-calculate the necessary reserve
576 double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
577 // We use ceiling so that if reserve_regions_d is > 0.0 (but
578 // smaller than 1.0) we'll get 1.
579 _reserve_regions = (size_t) ceil(reserve_regions_d);
580
581 if (_using_new_ratio_calculations) {
582 // -XX:NewRatio was specified so we need to update the
583 // young gen length when the heap size has changed.
584 update_young_list_size_using_newratio(new_number_of_regions);
585 }
586 }
587
588 size_t G1CollectorPolicy::calculate_young_list_desired_min_length(
589 size_t base_min_length) {
590 size_t desired_min_length = 0;
591 if (adaptive_young_list_length()) {
592 if (_alloc_rate_ms_seq->num() > 3) {
593 double now_sec = os::elapsedTime();
594 double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
595 double alloc_rate_ms = predict_alloc_rate_ms();
596 desired_min_length = (size_t) ceil(alloc_rate_ms * when_ms);
597 } else {
598 // otherwise we don't have enough info to make the prediction
599 }
600 }
601 desired_min_length += base_min_length;
602 // make sure we don't go below any user-defined minimum bound
603 return MAX2(_min_desired_young_length, desired_min_length);
604 }
605
606 size_t G1CollectorPolicy::calculate_young_list_desired_max_length() {
607 // Here, we might want to also take into account any additional
608 // constraints (i.e., user-defined minimum bound). Currently, we
609 // effectively don't set this bound.
610 return _max_desired_young_length;
611 }
612
613 void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
614 if (rs_lengths == (size_t) -1) {
615 // if it's set to the default value (-1), we should predict it;
616 // otherwise, use the given value.
617 rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
618 }
619
620 // Calculate the absolute and desired min bounds.
621
622 // This is how many young regions we already have (currently: the survivors).
623 size_t base_min_length = recorded_survivor_regions();
624 // This is the absolute minimum young length, which ensures that we
625 // can allocate one eden region in the worst-case.
626 size_t absolute_min_length = base_min_length + 1;
627 size_t desired_min_length =
628 calculate_young_list_desired_min_length(base_min_length);
629 if (desired_min_length < absolute_min_length) {
630 desired_min_length = absolute_min_length;
631 }
632
633 // Calculate the absolute and desired max bounds.
634
635 // We will try our best not to "eat" into the reserve.
636 size_t absolute_max_length = 0;
637 if (_free_regions_at_end_of_collection > _reserve_regions) {
638 absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
639 }
640 size_t desired_max_length = calculate_young_list_desired_max_length();
641 if (desired_max_length > absolute_max_length) {
642 desired_max_length = absolute_max_length;
643 }
644
645 size_t young_list_target_length = 0;
646 if (adaptive_young_list_length()) {
647 if (full_young_gcs()) {
648 young_list_target_length =
649 calculate_young_list_target_length(rs_lengths,
650 base_min_length,
651 desired_min_length,
652 desired_max_length);
653 _rs_lengths_prediction = rs_lengths;
654 } else {
655 // Don't calculate anything and let the code below bound it to
656 // the desired_min_length, i.e., do the next GC as soon as
657 // possible to maximize how many old regions we can add to it.
658 }
659 } else {
660 if (full_young_gcs()) {
661 young_list_target_length = _young_list_fixed_length;
662 } else {
663 // A bit arbitrary: during partially-young GCs we allocate half
664 // the young regions to try to add old regions to the CSet.
665 young_list_target_length = _young_list_fixed_length / 2;
666 // We choose to accept that we might go under the desired min
667 // length given that we intentionally ask for a smaller young gen.
668 desired_min_length = absolute_min_length;
669 }
670 }
671
672 // Make sure we don't go over the desired max length, nor under the
673 // desired min length. In case they clash, desired_min_length wins
674 // which is why that test is second.
675 if (young_list_target_length > desired_max_length) {
676 young_list_target_length = desired_max_length;
677 }
678 if (young_list_target_length < desired_min_length) {
679 young_list_target_length = desired_min_length;
680 }
681
682 assert(young_list_target_length > recorded_survivor_regions(),
683 "we should be able to allocate at least one eden region");
684 assert(young_list_target_length >= absolute_min_length, "post-condition");
685 _young_list_target_length = young_list_target_length;
686
687 update_max_gc_locker_expansion();
688 }
689
690 size_t
691 G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
692 size_t base_min_length,
693 size_t desired_min_length,
694 size_t desired_max_length) {
695 assert(adaptive_young_list_length(), "pre-condition");
696 assert(full_young_gcs(), "only call this for fully-young GCs");
697
698 // In case some edge-condition makes the desired max length too small...
699 if (desired_max_length <= desired_min_length) {
700 return desired_min_length;
701 }
702
703 // We'll adjust min_young_length and max_young_length not to include
704 // the already allocated young regions (i.e., so they reflect the
705 // min and max eden regions we'll allocate). The base_min_length
706 // will be reflected in the predictions by the
707 // survivor_regions_evac_time prediction.
708 assert(desired_min_length > base_min_length, "invariant");
709 size_t min_young_length = desired_min_length - base_min_length;
710 assert(desired_max_length > base_min_length, "invariant");
711 size_t max_young_length = desired_max_length - base_min_length;
712
713 double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
714 double survivor_regions_evac_time = predict_survivor_regions_evac_time();
715 size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
716 size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
717 size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
718 double base_time_ms =
719 predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
720 survivor_regions_evac_time;
721 size_t available_free_regions = _free_regions_at_end_of_collection;
722 size_t base_free_regions = 0;
723 if (available_free_regions > _reserve_regions) {
724 base_free_regions = available_free_regions - _reserve_regions;
725 }
726
727 // Here, we will make sure that the shortest young length that
728 // makes sense fits within the target pause time.
729
730 if (predict_will_fit(min_young_length, base_time_ms,
731 base_free_regions, target_pause_time_ms)) {
732 // The shortest young length will fit into the target pause time;
733 // we'll now check whether the absolute maximum number of young
734 // regions will fit in the target pause time. If not, we'll do
735 // a binary search between min_young_length and max_young_length.
736 if (predict_will_fit(max_young_length, base_time_ms,
737 base_free_regions, target_pause_time_ms)) {
738 // The maximum young length will fit into the target pause time.
739 // We are done so set min young length to the maximum length (as
740 // the result is assumed to be returned in min_young_length).
741 min_young_length = max_young_length;
742 } else {
743 // The maximum possible number of young regions will not fit within
744 // the target pause time so we'll search for the optimal
745 // length. The loop invariants are:
746 //
747 // min_young_length < max_young_length
748 // min_young_length is known to fit into the target pause time
749 // max_young_length is known not to fit into the target pause time
750 //
751 // Going into the loop we know the above hold as we've just
752 // checked them. Every time around the loop we check whether
753 // the middle value between min_young_length and
754 // max_young_length fits into the target pause time. If it
755 // does, it becomes the new min. If it doesn't, it becomes
756 // the new max. This way we maintain the loop invariants.
757
758 assert(min_young_length < max_young_length, "invariant");
759 size_t diff = (max_young_length - min_young_length) / 2;
760 while (diff > 0) {
761 size_t young_length = min_young_length + diff;
762 if (predict_will_fit(young_length, base_time_ms,
763 base_free_regions, target_pause_time_ms)) {
764 min_young_length = young_length;
765 } else {
766 max_young_length = young_length;
767 }
768 assert(min_young_length < max_young_length, "invariant");
769 diff = (max_young_length - min_young_length) / 2;
770 }
771 // The results is min_young_length which, according to the
772 // loop invariants, should fit within the target pause time.
773
774 // These are the post-conditions of the binary search above:
775 assert(min_young_length < max_young_length,
776 "otherwise we should have discovered that max_young_length "
777 "fits into the pause target and not done the binary search");
778 assert(predict_will_fit(min_young_length, base_time_ms,
779 base_free_regions, target_pause_time_ms),
780 "min_young_length, the result of the binary search, should "
781 "fit into the pause target");
782 assert(!predict_will_fit(min_young_length + 1, base_time_ms,
783 base_free_regions, target_pause_time_ms),
784 "min_young_length, the result of the binary search, should be "
785 "optimal, so no larger length should fit into the pause target");
786 }
787 } else {
788 // Even the minimum length doesn't fit into the pause time
789 // target, return it as the result nevertheless.
790 }
791 return base_min_length + min_young_length;
792 }
793
794 double G1CollectorPolicy::predict_survivor_regions_evac_time() {
795 double survivor_regions_evac_time = 0.0;
796 for (HeapRegion * r = _recorded_survivor_head;
797 r != NULL && r != _recorded_survivor_tail->get_next_young_region();
798 r = r->get_next_young_region()) {
799 survivor_regions_evac_time += predict_region_elapsed_time_ms(r, true);
800 }
801 return survivor_regions_evac_time;
802 }
803
804 void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
805 guarantee( adaptive_young_list_length(), "should not call this otherwise" );
806
807 size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
808 if (rs_lengths > _rs_lengths_prediction) {
809 // add 10% to avoid having to recalculate often
810 size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
811 update_young_list_target_length(rs_lengths_prediction);
812 }
813 }
814
815
816
817 HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
818 bool is_tlab,
819 bool* gc_overhead_limit_was_exceeded) {
820 guarantee(false, "Not using this policy feature yet.");
821 return NULL;
822 }
823
824 // This method controls how a collector handles one or more
825 // of its generations being fully allocated.
826 HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
827 bool is_tlab) {
828 guarantee(false, "Not using this policy feature yet.");
829 return NULL;
830 }
831
832
833 #ifndef PRODUCT
834 bool G1CollectorPolicy::verify_young_ages() {
835 HeapRegion* head = _g1->young_list()->first_region();
836 return
837 verify_young_ages(head, _short_lived_surv_rate_group);
838 // also call verify_young_ages on any additional surv rate groups
839 }
840
841 bool
842 G1CollectorPolicy::verify_young_ages(HeapRegion* head,
843 SurvRateGroup *surv_rate_group) {
844 guarantee( surv_rate_group != NULL, "pre-condition" );
845
846 const char* name = surv_rate_group->name();
847 bool ret = true;
848 int prev_age = -1;
849
850 for (HeapRegion* curr = head;
851 curr != NULL;
852 curr = curr->get_next_young_region()) {
853 SurvRateGroup* group = curr->surv_rate_group();
854 if (group == NULL && !curr->is_survivor()) {
855 gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
856 ret = false;
857 }
858
859 if (surv_rate_group == group) {
860 int age = curr->age_in_surv_rate_group();
861
862 if (age < 0) {
863 gclog_or_tty->print_cr("## %s: encountered negative age", name);
864 ret = false;
865 }
866
867 if (age <= prev_age) {
868 gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
869 "(%d, %d)", name, age, prev_age);
870 ret = false;
871 }
872 prev_age = age;
873 }
874 }
875
876 return ret;
877 }
878 #endif // PRODUCT
879
880 void G1CollectorPolicy::record_full_collection_start() {
881 _cur_collection_start_sec = os::elapsedTime();
882 // Release the future to-space so that it is available for compaction into.
883 _g1->set_full_collection();
884 }
885
886 void G1CollectorPolicy::record_full_collection_end() {
887 // Consider this like a collection pause for the purposes of allocation
888 // since last pause.
889 double end_sec = os::elapsedTime();
890 double full_gc_time_sec = end_sec - _cur_collection_start_sec;
891 double full_gc_time_ms = full_gc_time_sec * 1000.0;
892
893 _all_full_gc_times_ms->add(full_gc_time_ms);
894
895 update_recent_gc_times(end_sec, full_gc_time_ms);
896
897 _g1->clear_full_collection();
898
899 // "Nuke" the heuristics that control the fully/partially young GC
900 // transitions and make sure we start with fully young GCs after the
901 // Full GC.
902 set_full_young_gcs(true);
903 _last_full_young_gc = false;
904 _should_revert_to_full_young_gcs = false;
905 clear_initiate_conc_mark_if_possible();
906 clear_during_initial_mark_pause();
907 _known_garbage_bytes = 0;
908 _known_garbage_ratio = 0.0;
909 _in_marking_window = false;
910 _in_marking_window_im = false;
911
912 _short_lived_surv_rate_group->start_adding_regions();
913 // also call this on any additional surv rate groups
914
915 record_survivor_regions(0, NULL, NULL);
916
917 _prev_region_num_young = _region_num_young;
918 _prev_region_num_tenured = _region_num_tenured;
919
920 _free_regions_at_end_of_collection = _g1->free_regions();
921 // Reset survivors SurvRateGroup.
922 _survivor_surv_rate_group->reset();
923 update_young_list_target_length();
924 }
925
926 void G1CollectorPolicy::record_stop_world_start() {
927 _stop_world_start = os::elapsedTime();
928 }
929
930 void G1CollectorPolicy::record_collection_pause_start(double start_time_sec,
931 size_t start_used) {
932 if (PrintGCDetails) {
933 gclog_or_tty->stamp(PrintGCTimeStamps);
934 gclog_or_tty->print("[GC pause");
935 gclog_or_tty->print(" (%s)", full_young_gcs() ? "young" : "partial");
936 }
937
938 // We only need to do this here as the policy will only be applied
939 // to the GC we're about to start. so, no point is calculating this
940 // every time we calculate / recalculate the target young length.
941 update_survivors_policy();
942
943 assert(_g1->used() == _g1->recalculate_used(),
944 err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
945 _g1->used(), _g1->recalculate_used()));
946
947 double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
948 _all_stop_world_times_ms->add(s_w_t_ms);
949 _stop_world_start = 0.0;
950
951 _cur_collection_start_sec = start_time_sec;
952 _cur_collection_pause_used_at_start_bytes = start_used;
953 _cur_collection_pause_used_regions_at_start = _g1->used_regions();
954 _pending_cards = _g1->pending_card_num();
955 _max_pending_cards = _g1->max_pending_card_num();
956
957 _bytes_in_collection_set_before_gc = 0;
958 _bytes_copied_during_gc = 0;
959
960 YoungList* young_list = _g1->young_list();
961 _eden_bytes_before_gc = young_list->eden_used_bytes();
962 _survivor_bytes_before_gc = young_list->survivor_used_bytes();
963 _capacity_before_gc = _g1->capacity();
964
965 #ifdef DEBUG
966 // initialise these to something well known so that we can spot
967 // if they are not set properly
968
969 for (int i = 0; i < _parallel_gc_threads; ++i) {
970 _par_last_gc_worker_start_times_ms[i] = -1234.0;
971 _par_last_ext_root_scan_times_ms[i] = -1234.0;
972 _par_last_mark_stack_scan_times_ms[i] = -1234.0;
973 _par_last_update_rs_times_ms[i] = -1234.0;
974 _par_last_update_rs_processed_buffers[i] = -1234.0;
975 _par_last_scan_rs_times_ms[i] = -1234.0;
976 _par_last_obj_copy_times_ms[i] = -1234.0;
977 _par_last_termination_times_ms[i] = -1234.0;
978 _par_last_termination_attempts[i] = -1234.0;
979 _par_last_gc_worker_end_times_ms[i] = -1234.0;
980 _par_last_gc_worker_times_ms[i] = -1234.0;
981 }
982 #endif
983
984 for (int i = 0; i < _aux_num; ++i) {
985 _cur_aux_times_ms[i] = 0.0;
986 _cur_aux_times_set[i] = false;
987 }
988
989 _satb_drain_time_set = false;
990 _last_satb_drain_processed_buffers = -1;
991
992 _last_young_gc_full = false;
993
994 // do that for any other surv rate groups
995 _short_lived_surv_rate_group->stop_adding_regions();
996 _survivors_age_table.clear();
997
998 assert( verify_young_ages(), "region age verification" );
999 }
1000
1001 void G1CollectorPolicy::record_mark_closure_time(double mark_closure_time_ms) {
1002 _mark_closure_time_ms = mark_closure_time_ms;
1003 }
1004
1005 void G1CollectorPolicy::record_concurrent_mark_init_end(double
1006 mark_init_elapsed_time_ms) {
1007 _during_marking = true;
1008 assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
1009 clear_during_initial_mark_pause();
1010 _cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
1011 }
1012
1013 void G1CollectorPolicy::record_concurrent_mark_remark_start() {
1014 _mark_remark_start_sec = os::elapsedTime();
1015 _during_marking = false;
1016 }
1017
1018 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
1019 double end_time_sec = os::elapsedTime();
1020 double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
1021 _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
1022 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1023 _prev_collection_pause_end_ms += elapsed_time_ms;
1024
1025 _mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
1026 }
1027
1028 void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
1029 _mark_cleanup_start_sec = os::elapsedTime();
1030 }
1031
1032 void
1033 G1CollectorPolicy::record_concurrent_mark_cleanup_end(size_t freed_bytes,
1034 size_t max_live_bytes) {
1035 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
1036 record_concurrent_mark_cleanup_end_work2();
1037 }
1038
1039 void
1040 G1CollectorPolicy::
1041 record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
1042 size_t max_live_bytes) {
1043 if (_n_marks < 2) {
1044 _n_marks++;
1045 }
1046 }
1047
1048 // The important thing about this is that it includes "os::elapsedTime".
1049 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
1050 double end_time_sec = os::elapsedTime();
1051 double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
1052 _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
1053 _cur_mark_stop_world_time_ms += elapsed_time_ms;
1054 _prev_collection_pause_end_ms += elapsed_time_ms;
1055
1056 _mmu_tracker->add_pause(_mark_cleanup_start_sec, end_time_sec, true);
1057
1058 _num_markings++;
1059 _n_pauses_at_mark_end = _n_pauses;
1060 _n_marks_since_last_pause++;
1061 }
1062
1063 void
1064 G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
1065 _should_revert_to_full_young_gcs = false;
1066 _last_full_young_gc = true;
1067 _in_marking_window = false;
1068 }
1069
1070 void G1CollectorPolicy::record_concurrent_pause() {
1071 if (_stop_world_start > 0.0) {
1072 double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
1073 _all_yield_times_ms->add(yield_ms);
1074 }
1075 }
1076
1077 void G1CollectorPolicy::record_concurrent_pause_end() {
1078 }
1079
1080 template<class T>
1081 T sum_of(T* sum_arr, int start, int n, int N) {
1082 T sum = (T)0;
1083 for (int i = 0; i < n; i++) {
1084 int j = (start + i) % N;
1085 sum += sum_arr[j];
1086 }
1087 return sum;
1088 }
1089
1090 void G1CollectorPolicy::print_par_stats(int level,
1091 const char* str,
1092 double* data) {
1093 double min = data[0], max = data[0];
1094 double total = 0.0;
1095 LineBuffer buf(level);
1096 buf.append("[%s (ms):", str);
1097 for (uint i = 0; i < ParallelGCThreads; ++i) {
1098 double val = data[i];
1099 if (val < min)
1100 min = val;
1101 if (val > max)
1102 max = val;
1103 total += val;
1104 buf.append(" %3.1lf", val);
1105 }
1106 buf.append_and_print_cr("");
1107 double avg = total / (double) ParallelGCThreads;
1108 buf.append_and_print_cr(" Avg: %5.1lf, Min: %5.1lf, Max: %5.1lf, Diff: %5.1lf]",
1109 avg, min, max, max - min);
1110 }
1111
1112 void G1CollectorPolicy::print_par_sizes(int level,
1113 const char* str,
1114 double* data) {
1115 double min = data[0], max = data[0];
1116 double total = 0.0;
1117 LineBuffer buf(level);
1118 buf.append("[%s :", str);
1119 for (uint i = 0; i < ParallelGCThreads; ++i) {
1120 double val = data[i];
1121 if (val < min)
1122 min = val;
1123 if (val > max)
1124 max = val;
1125 total += val;
1126 buf.append(" %d", (int) val);
1127 }
1128 buf.append_and_print_cr("");
1129 double avg = total / (double) ParallelGCThreads;
1130 buf.append_and_print_cr(" Sum: %d, Avg: %d, Min: %d, Max: %d, Diff: %d]",
1131 (int)total, (int)avg, (int)min, (int)max, (int)max - (int)min);
1132 }
1133
1134 void G1CollectorPolicy::print_stats (int level,
1135 const char* str,
1136 double value) {
1137 LineBuffer(level).append_and_print_cr("[%s: %5.1lf ms]", str, value);
1138 }
1139
1140 void G1CollectorPolicy::print_stats (int level,
1141 const char* str,
1142 int value) {
1143 LineBuffer(level).append_and_print_cr("[%s: %d]", str, value);
1144 }
1145
1146 double G1CollectorPolicy::avg_value (double* data) {
1147 if (G1CollectedHeap::use_parallel_gc_threads()) {
1148 double ret = 0.0;
1149 for (uint i = 0; i < ParallelGCThreads; ++i)
1150 ret += data[i];
1151 return ret / (double) ParallelGCThreads;
1152 } else {
1153 return data[0];
1154 }
1155 }
1156
1157 double G1CollectorPolicy::max_value (double* data) {
1158 if (G1CollectedHeap::use_parallel_gc_threads()) {
1159 double ret = data[0];
1160 for (uint i = 1; i < ParallelGCThreads; ++i)
1161 if (data[i] > ret)
1162 ret = data[i];
1163 return ret;
1164 } else {
1165 return data[0];
1166 }
1167 }
1168
1169 double G1CollectorPolicy::sum_of_values (double* data) {
1170 if (G1CollectedHeap::use_parallel_gc_threads()) {
1171 double sum = 0.0;
1172 for (uint i = 0; i < ParallelGCThreads; i++)
1173 sum += data[i];
1174 return sum;
1175 } else {
1176 return data[0];
1177 }
1178 }
1179
1180 double G1CollectorPolicy::max_sum (double* data1,
1181 double* data2) {
1182 double ret = data1[0] + data2[0];
1183
1184 if (G1CollectedHeap::use_parallel_gc_threads()) {
1185 for (uint i = 1; i < ParallelGCThreads; ++i) {
1186 double data = data1[i] + data2[i];
1187 if (data > ret)
1188 ret = data;
1189 }
1190 }
1191 return ret;
1192 }
1193
1194 // Anything below that is considered to be zero
1195 #define MIN_TIMER_GRANULARITY 0.0000001
1196
1197 void G1CollectorPolicy::record_collection_pause_end() {
1198 double end_time_sec = os::elapsedTime();
1199 double elapsed_ms = _last_pause_time_ms;
1200 bool parallel = G1CollectedHeap::use_parallel_gc_threads();
1201 size_t rs_size =
1202 _cur_collection_pause_used_regions_at_start - collection_set_size();
1203 size_t cur_used_bytes = _g1->used();
1204 assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
1205 bool last_pause_included_initial_mark = false;
1206 bool update_stats = !_g1->evacuation_failed();
1207
1208 #ifndef PRODUCT
1209 if (G1YoungSurvRateVerbose) {
1210 gclog_or_tty->print_cr("");
1211 _short_lived_surv_rate_group->print();
1212 // do that for any other surv rate groups too
1213 }
1214 #endif // PRODUCT
1215
1216 last_pause_included_initial_mark = during_initial_mark_pause();
1217 if (last_pause_included_initial_mark)
1218 record_concurrent_mark_init_end(0.0);
1219
1220 size_t marking_initiating_used_threshold =
1221 (_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
1222
1223 if (!_g1->mark_in_progress() && !_last_full_young_gc) {
1224 assert(!last_pause_included_initial_mark, "invariant");
1225 if (cur_used_bytes > marking_initiating_used_threshold) {
1226 if (cur_used_bytes > _prev_collection_pause_used_at_end_bytes) {
1227 assert(!during_initial_mark_pause(), "we should not see this here");
1228
1229 ergo_verbose3(ErgoConcCycles,
1230 "request concurrent cycle initiation",
1231 ergo_format_reason("occupancy higher than threshold")
1232 ergo_format_byte("occupancy")
1233 ergo_format_byte_perc("threshold"),
1234 cur_used_bytes,
1235 marking_initiating_used_threshold,
1236 (double) InitiatingHeapOccupancyPercent);
1237
1238 // Note: this might have already been set, if during the last
1239 // pause we decided to start a cycle but at the beginning of
1240 // this pause we decided to postpone it. That's OK.
1241 set_initiate_conc_mark_if_possible();
1242 } else {
1243 ergo_verbose2(ErgoConcCycles,
1244 "do not request concurrent cycle initiation",
1245 ergo_format_reason("occupancy lower than previous occupancy")
1246 ergo_format_byte("occupancy")
1247 ergo_format_byte("previous occupancy"),
1248 cur_used_bytes,
1249 _prev_collection_pause_used_at_end_bytes);
1250 }
1251 }
1252 }
1253
1254 _prev_collection_pause_used_at_end_bytes = cur_used_bytes;
1255
1256 _mmu_tracker->add_pause(end_time_sec - elapsed_ms/1000.0,
1257 end_time_sec, false);
1258
1259 guarantee(_cur_collection_pause_used_regions_at_start >=
1260 collection_set_size(),
1261 "Negative RS size?");
1262
1263 // This assert is exempted when we're doing parallel collection pauses,
1264 // because the fragmentation caused by the parallel GC allocation buffers
1265 // can lead to more memory being used during collection than was used
1266 // before. Best leave this out until the fragmentation problem is fixed.
1267 // Pauses in which evacuation failed can also lead to negative
1268 // collections, since no space is reclaimed from a region containing an
1269 // object whose evacuation failed.
1270 // Further, we're now always doing parallel collection. But I'm still
1271 // leaving this here as a placeholder for a more precise assertion later.
1272 // (DLD, 10/05.)
1273 assert((true || parallel) // Always using GC LABs now.
1274 || _g1->evacuation_failed()
1275 || _cur_collection_pause_used_at_start_bytes >= cur_used_bytes,
1276 "Negative collection");
1277
1278 size_t freed_bytes =
1279 _cur_collection_pause_used_at_start_bytes - cur_used_bytes;
1280 size_t surviving_bytes = _collection_set_bytes_used_before - freed_bytes;
1281
1282 double survival_fraction =
1283 (double)surviving_bytes/
1284 (double)_collection_set_bytes_used_before;
1285
1286 _n_pauses++;
1287
1288 double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
1289 double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
1290 double update_rs_time = avg_value(_par_last_update_rs_times_ms);
1291 double update_rs_processed_buffers =
1292 sum_of_values(_par_last_update_rs_processed_buffers);
1293 double scan_rs_time = avg_value(_par_last_scan_rs_times_ms);
1294 double obj_copy_time = avg_value(_par_last_obj_copy_times_ms);
1295 double termination_time = avg_value(_par_last_termination_times_ms);
1296
1297 double parallel_known_time = update_rs_time +
1298 ext_root_scan_time +
1299 mark_stack_scan_time +
1300 scan_rs_time +
1301 obj_copy_time +
1302 termination_time;
1303
1304 double parallel_other_time = _cur_collection_par_time_ms - parallel_known_time;
1305
1306 PauseSummary* summary = _summary;
1307
1308 if (update_stats) {
1309 _recent_rs_scan_times_ms->add(scan_rs_time);
1310 _recent_pause_times_ms->add(elapsed_ms);
1311 _recent_rs_sizes->add(rs_size);
1312
1313 MainBodySummary* body_summary = summary->main_body_summary();
1314 guarantee(body_summary != NULL, "should not be null!");
1315
1316 if (_satb_drain_time_set)
1317 body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
1318 else
1319 body_summary->record_satb_drain_time_ms(0.0);
1320
1321 body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
1322 body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
1323 body_summary->record_update_rs_time_ms(update_rs_time);
1324 body_summary->record_scan_rs_time_ms(scan_rs_time);
1325 body_summary->record_obj_copy_time_ms(obj_copy_time);
1326 if (parallel) {
1327 body_summary->record_parallel_time_ms(_cur_collection_par_time_ms);
1328 body_summary->record_clear_ct_time_ms(_cur_clear_ct_time_ms);
1329 body_summary->record_termination_time_ms(termination_time);
1330 body_summary->record_parallel_other_time_ms(parallel_other_time);
1331 }
1332 body_summary->record_mark_closure_time_ms(_mark_closure_time_ms);
1333
1334 // We exempt parallel collection from this check because Alloc Buffer
1335 // fragmentation can produce negative collections. Same with evac
1336 // failure.
1337 // Further, we're now always doing parallel collection. But I'm still
1338 // leaving this here as a placeholder for a more precise assertion later.
1339 // (DLD, 10/05.
1340 assert((true || parallel)
1341 || _g1->evacuation_failed()
1342 || surviving_bytes <= _collection_set_bytes_used_before,
1343 "Or else negative collection!");
1344 _recent_CS_bytes_used_before->add(_collection_set_bytes_used_before);
1345 _recent_CS_bytes_surviving->add(surviving_bytes);
1346
1347 // this is where we update the allocation rate of the application
1348 double app_time_ms =
1349 (_cur_collection_start_sec * 1000.0 - _prev_collection_pause_end_ms);
1350 if (app_time_ms < MIN_TIMER_GRANULARITY) {
1351 // This usually happens due to the timer not having the required
1352 // granularity. Some Linuxes are the usual culprits.
1353 // We'll just set it to something (arbitrarily) small.
1354 app_time_ms = 1.0;
1355 }
1356 size_t regions_allocated =
1357 (_region_num_young - _prev_region_num_young) +
1358 (_region_num_tenured - _prev_region_num_tenured);
1359 double alloc_rate_ms = (double) regions_allocated / app_time_ms;
1360 _alloc_rate_ms_seq->add(alloc_rate_ms);
1361 _prev_region_num_young = _region_num_young;
1362 _prev_region_num_tenured = _region_num_tenured;
1363
1364 double interval_ms =
1365 (end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
1366 update_recent_gc_times(end_time_sec, elapsed_ms);
1367 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
1368 if (recent_avg_pause_time_ratio() < 0.0 ||
1369 (recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
1370 #ifndef PRODUCT
1371 // Dump info to allow post-facto debugging
1372 gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
1373 gclog_or_tty->print_cr("-------------------------------------------");
1374 gclog_or_tty->print_cr("Recent GC Times (ms):");
1375 _recent_gc_times_ms->dump();
1376 gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
1377 _recent_prev_end_times_for_all_gcs_sec->dump();
1378 gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
1379 _recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
1380 // In debug mode, terminate the JVM if the user wants to debug at this point.
1381 assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
1382 #endif // !PRODUCT
1383 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
1384 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
1385 if (_recent_avg_pause_time_ratio < 0.0) {
1386 _recent_avg_pause_time_ratio = 0.0;
1387 } else {
1388 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
1389 _recent_avg_pause_time_ratio = 1.0;
1390 }
1391 }
1392 }
1393
1394 if (G1PolicyVerbose > 1) {
1395 gclog_or_tty->print_cr(" Recording collection pause(%d)", _n_pauses);
1396 }
1397
1398 if (G1PolicyVerbose > 1) {
1399 gclog_or_tty->print_cr(" ET: %10.6f ms (avg: %10.6f ms)\n"
1400 " ET-RS: %10.6f ms (avg: %10.6f ms)\n"
1401 " |RS|: " SIZE_FORMAT,
1402 elapsed_ms, recent_avg_time_for_pauses_ms(),
1403 scan_rs_time, recent_avg_time_for_rs_scan_ms(),
1404 rs_size);
1405
1406 gclog_or_tty->print_cr(" Used at start: " SIZE_FORMAT"K"
1407 " At end " SIZE_FORMAT "K\n"
1408 " garbage : " SIZE_FORMAT "K"
1409 " of " SIZE_FORMAT "K\n"
1410 " survival : %6.2f%% (%6.2f%% avg)",
1411 _cur_collection_pause_used_at_start_bytes/K,
1412 _g1->used()/K, freed_bytes/K,
1413 _collection_set_bytes_used_before/K,
1414 survival_fraction*100.0,
1415 recent_avg_survival_fraction()*100.0);
1416 gclog_or_tty->print_cr(" Recent %% gc pause time: %6.2f",
1417 recent_avg_pause_time_ratio() * 100.0);
1418 }
1419
1420 double other_time_ms = elapsed_ms;
1421
1422 if (_satb_drain_time_set) {
1423 other_time_ms -= _cur_satb_drain_time_ms;
1424 }
1425
1426 if (parallel) {
1427 other_time_ms -= _cur_collection_par_time_ms + _cur_clear_ct_time_ms;
1428 } else {
1429 other_time_ms -=
1430 update_rs_time +
1431 ext_root_scan_time + mark_stack_scan_time +
1432 scan_rs_time + obj_copy_time;
1433 }
1434
1435 if (PrintGCDetails) {
1436 gclog_or_tty->print_cr("%s, %1.8lf secs]",
1437 (last_pause_included_initial_mark) ? " (initial-mark)" : "",
1438 elapsed_ms / 1000.0);
1439
1440 if (_satb_drain_time_set) {
1441 print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
1442 }
1443 if (_last_satb_drain_processed_buffers >= 0) {
1444 print_stats(2, "Processed Buffers", _last_satb_drain_processed_buffers);
1445 }
1446 if (parallel) {
1447 print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
1448 print_par_stats(2, "GC Worker Start Time", _par_last_gc_worker_start_times_ms);
1449 print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
1450 print_par_sizes(3, "Processed Buffers", _par_last_update_rs_processed_buffers);
1451 print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
1452 print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
1453 print_par_stats(2, "Scan RS", _par_last_scan_rs_times_ms);
1454 print_par_stats(2, "Object Copy", _par_last_obj_copy_times_ms);
1455 print_par_stats(2, "Termination", _par_last_termination_times_ms);
1456 print_par_sizes(3, "Termination Attempts", _par_last_termination_attempts);
1457 print_par_stats(2, "GC Worker End Time", _par_last_gc_worker_end_times_ms);
1458
1459 for (int i = 0; i < _parallel_gc_threads; i++) {
1460 _par_last_gc_worker_times_ms[i] = _par_last_gc_worker_end_times_ms[i] - _par_last_gc_worker_start_times_ms[i];
1461 }
1462 print_par_stats(2, "GC Worker Times", _par_last_gc_worker_times_ms);
1463
1464 print_stats(2, "Parallel Other", parallel_other_time);
1465 print_stats(1, "Clear CT", _cur_clear_ct_time_ms);
1466 } else {
1467 print_stats(1, "Update RS", update_rs_time);
1468 print_stats(2, "Processed Buffers",
1469 (int)update_rs_processed_buffers);
1470 print_stats(1, "Ext Root Scanning", ext_root_scan_time);
1471 print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
1472 print_stats(1, "Scan RS", scan_rs_time);
1473 print_stats(1, "Object Copying", obj_copy_time);
1474 }
1475 #ifndef PRODUCT
1476 print_stats(1, "Cur Clear CC", _cur_clear_cc_time_ms);
1477 print_stats(1, "Cum Clear CC", _cum_clear_cc_time_ms);
1478 print_stats(1, "Min Clear CC", _min_clear_cc_time_ms);
1479 print_stats(1, "Max Clear CC", _max_clear_cc_time_ms);
1480 if (_num_cc_clears > 0) {
1481 print_stats(1, "Avg Clear CC", _cum_clear_cc_time_ms / ((double)_num_cc_clears));
1482 }
1483 #endif
1484 print_stats(1, "Other", other_time_ms);
1485 print_stats(2, "Choose CSet", _recorded_young_cset_choice_time_ms);
1486 print_stats(2, "Ref Proc", _cur_ref_proc_time_ms);
1487 print_stats(2, "Ref Enq", _cur_ref_enq_time_ms);
1488
1489 for (int i = 0; i < _aux_num; ++i) {
1490 if (_cur_aux_times_set[i]) {
1491 char buffer[96];
1492 sprintf(buffer, "Aux%d", i);
1493 print_stats(1, buffer, _cur_aux_times_ms[i]);
1494 }
1495 }
1496 }
1497
1498 _all_pause_times_ms->add(elapsed_ms);
1499 if (update_stats) {
1500 summary->record_total_time_ms(elapsed_ms);
1501 summary->record_other_time_ms(other_time_ms);
1502 }
1503 for (int i = 0; i < _aux_num; ++i)
1504 if (_cur_aux_times_set[i])
1505 _all_aux_times_ms[i].add(_cur_aux_times_ms[i]);
1506
1507 // Reset marks-between-pauses counter.
1508 _n_marks_since_last_pause = 0;
1509
1510 // Update the efficiency-since-mark vars.
1511 double proc_ms = elapsed_ms * (double) _parallel_gc_threads;
1512 if (elapsed_ms < MIN_TIMER_GRANULARITY) {
1513 // This usually happens due to the timer not having the required
1514 // granularity. Some Linuxes are the usual culprits.
1515 // We'll just set it to something (arbitrarily) small.
1516 proc_ms = 1.0;
1517 }
1518 double cur_efficiency = (double) freed_bytes / proc_ms;
1519
1520 bool new_in_marking_window = _in_marking_window;
1521 bool new_in_marking_window_im = false;
1522 if (during_initial_mark_pause()) {
1523 new_in_marking_window = true;
1524 new_in_marking_window_im = true;
1525 }
1526
1527 if (_last_full_young_gc) {
1528 ergo_verbose2(ErgoPartiallyYoungGCs,
1529 "start partially-young GCs",
1530 ergo_format_byte_perc("known garbage"),
1531 _known_garbage_bytes, _known_garbage_ratio * 100.0);
1532 set_full_young_gcs(false);
1533 _last_full_young_gc = false;
1534 }
1535
1536 if ( !_last_young_gc_full ) {
1537 if (_should_revert_to_full_young_gcs) {
1538 ergo_verbose2(ErgoPartiallyYoungGCs,
1539 "end partially-young GCs",
1540 ergo_format_reason("partially-young GCs end requested")
1541 ergo_format_byte_perc("known garbage"),
1542 _known_garbage_bytes, _known_garbage_ratio * 100.0);
1543 set_full_young_gcs(true);
1544 } else if (_known_garbage_ratio < 0.05) {
1545 ergo_verbose3(ErgoPartiallyYoungGCs,
1546 "end partially-young GCs",
1547 ergo_format_reason("known garbage percent lower than threshold")
1548 ergo_format_byte_perc("known garbage")
1549 ergo_format_perc("threshold"),
1550 _known_garbage_bytes, _known_garbage_ratio * 100.0,
1551 0.05 * 100.0);
1552 set_full_young_gcs(true);
1553 } else if (adaptive_young_list_length() &&
1554 (get_gc_eff_factor() * cur_efficiency < predict_young_gc_eff())) {
1555 ergo_verbose5(ErgoPartiallyYoungGCs,
1556 "end partially-young GCs",
1557 ergo_format_reason("current GC efficiency lower than "
1558 "predicted fully-young GC efficiency")
1559 ergo_format_double("GC efficiency factor")
1560 ergo_format_double("current GC efficiency")
1561 ergo_format_double("predicted fully-young GC efficiency")
1562 ergo_format_byte_perc("known garbage"),
1563 get_gc_eff_factor(), cur_efficiency,
1564 predict_young_gc_eff(),
1565 _known_garbage_bytes, _known_garbage_ratio * 100.0);
1566 set_full_young_gcs(true);
1567 }
1568 }
1569 _should_revert_to_full_young_gcs = false;
1570
1571 if (_last_young_gc_full && !_during_marking) {
1572 _young_gc_eff_seq->add(cur_efficiency);
1573 }
1574
1575 _short_lived_surv_rate_group->start_adding_regions();
1576 // do that for any other surv rate groupsx
1577
1578 // <NEW PREDICTION>
1579
1580 if (update_stats) {
1581 double pause_time_ms = elapsed_ms;
1582
1583 size_t diff = 0;
1584 if (_max_pending_cards >= _pending_cards)
1585 diff = _max_pending_cards - _pending_cards;
1586 _pending_card_diff_seq->add((double) diff);
1587
1588 double cost_per_card_ms = 0.0;
1589 if (_pending_cards > 0) {
1590 cost_per_card_ms = update_rs_time / (double) _pending_cards;
1591 _cost_per_card_ms_seq->add(cost_per_card_ms);
1592 }
1593
1594 size_t cards_scanned = _g1->cards_scanned();
1595
1596 double cost_per_entry_ms = 0.0;
1597 if (cards_scanned > 10) {
1598 cost_per_entry_ms = scan_rs_time / (double) cards_scanned;
1599 if (_last_young_gc_full)
1600 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
1601 else
1602 _partially_young_cost_per_entry_ms_seq->add(cost_per_entry_ms);
1603 }
1604
1605 if (_max_rs_lengths > 0) {
1606 double cards_per_entry_ratio =
1607 (double) cards_scanned / (double) _max_rs_lengths;
1608 if (_last_young_gc_full)
1609 _fully_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1610 else
1611 _partially_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
1612 }
1613
1614 size_t rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
1615 if (rs_length_diff >= 0)
1616 _rs_length_diff_seq->add((double) rs_length_diff);
1617
1618 size_t copied_bytes = surviving_bytes;
1619 double cost_per_byte_ms = 0.0;
1620 if (copied_bytes > 0) {
1621 cost_per_byte_ms = obj_copy_time / (double) copied_bytes;
1622 if (_in_marking_window)
1623 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
1624 else
1625 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
1626 }
1627
1628 double all_other_time_ms = pause_time_ms -
1629 (update_rs_time + scan_rs_time + obj_copy_time +
1630 _mark_closure_time_ms + termination_time);
1631
1632 double young_other_time_ms = 0.0;
1633 if (_recorded_young_regions > 0) {
1634 young_other_time_ms =
1635 _recorded_young_cset_choice_time_ms +
1636 _recorded_young_free_cset_time_ms;
1637 _young_other_cost_per_region_ms_seq->add(young_other_time_ms /
1638 (double) _recorded_young_regions);
1639 }
1640 double non_young_other_time_ms = 0.0;
1641 if (_recorded_non_young_regions > 0) {
1642 non_young_other_time_ms =
1643 _recorded_non_young_cset_choice_time_ms +
1644 _recorded_non_young_free_cset_time_ms;
1645
1646 _non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
1647 (double) _recorded_non_young_regions);
1648 }
1649
1650 double constant_other_time_ms = all_other_time_ms -
1651 (young_other_time_ms + non_young_other_time_ms);
1652 _constant_other_time_ms_seq->add(constant_other_time_ms);
1653
1654 double survival_ratio = 0.0;
1655 if (_bytes_in_collection_set_before_gc > 0) {
1656 survival_ratio = (double) _bytes_copied_during_gc /
1657 (double) _bytes_in_collection_set_before_gc;
1658 }
1659
1660 _pending_cards_seq->add((double) _pending_cards);
1661 _scanned_cards_seq->add((double) cards_scanned);
1662 _rs_lengths_seq->add((double) _max_rs_lengths);
1663
1664 double expensive_region_limit_ms =
1665 (double) MaxGCPauseMillis - predict_constant_other_time_ms();
1666 if (expensive_region_limit_ms < 0.0) {
1667 // this means that the other time was predicted to be longer than
1668 // than the max pause time
1669 expensive_region_limit_ms = (double) MaxGCPauseMillis;
1670 }
1671 _expensive_region_limit_ms = expensive_region_limit_ms;
1672
1673 if (PREDICTIONS_VERBOSE) {
1674 gclog_or_tty->print_cr("");
1675 gclog_or_tty->print_cr("PREDICTIONS %1.4lf %d "
1676 "REGIONS %d %d %d "
1677 "PENDING_CARDS %d %d "
1678 "CARDS_SCANNED %d %d "
1679 "RS_LENGTHS %d %d "
1680 "RS_UPDATE %1.6lf %1.6lf RS_SCAN %1.6lf %1.6lf "
1681 "SURVIVAL_RATIO %1.6lf %1.6lf "
1682 "OBJECT_COPY %1.6lf %1.6lf OTHER_CONSTANT %1.6lf %1.6lf "
1683 "OTHER_YOUNG %1.6lf %1.6lf "
1684 "OTHER_NON_YOUNG %1.6lf %1.6lf "
1685 "VTIME_DIFF %1.6lf TERMINATION %1.6lf "
1686 "ELAPSED %1.6lf %1.6lf ",
1687 _cur_collection_start_sec,
1688 (!_last_young_gc_full) ? 2 :
1689 (last_pause_included_initial_mark) ? 1 : 0,
1690 _recorded_region_num,
1691 _recorded_young_regions,
1692 _recorded_non_young_regions,
1693 _predicted_pending_cards, _pending_cards,
1694 _predicted_cards_scanned, cards_scanned,
1695 _predicted_rs_lengths, _max_rs_lengths,
1696 _predicted_rs_update_time_ms, update_rs_time,
1697 _predicted_rs_scan_time_ms, scan_rs_time,
1698 _predicted_survival_ratio, survival_ratio,
1699 _predicted_object_copy_time_ms, obj_copy_time,
1700 _predicted_constant_other_time_ms, constant_other_time_ms,
1701 _predicted_young_other_time_ms, young_other_time_ms,
1702 _predicted_non_young_other_time_ms,
1703 non_young_other_time_ms,
1704 _vtime_diff_ms, termination_time,
1705 _predicted_pause_time_ms, elapsed_ms);
1706 }
1707
1708 if (G1PolicyVerbose > 0) {
1709 gclog_or_tty->print_cr("Pause Time, predicted: %1.4lfms (predicted %s), actual: %1.4lfms",
1710 _predicted_pause_time_ms,
1711 (_within_target) ? "within" : "outside",
1712 elapsed_ms);
1713 }
1714
1715 }
1716
1717 _in_marking_window = new_in_marking_window;
1718 _in_marking_window_im = new_in_marking_window_im;
1719 _free_regions_at_end_of_collection = _g1->free_regions();
1720 update_young_list_target_length();
1721
1722 // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
1723 double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
1724 adjust_concurrent_refinement(update_rs_time, update_rs_processed_buffers, update_rs_time_goal_ms);
1725 // </NEW PREDICTION>
1726 }
1727
1728 #define EXT_SIZE_FORMAT "%d%s"
1729 #define EXT_SIZE_PARAMS(bytes) \
1730 byte_size_in_proper_unit((bytes)), \
1731 proper_unit_for_byte_size((bytes))
1732
1733 void G1CollectorPolicy::print_heap_transition() {
1734 if (PrintGCDetails) {
1735 YoungList* young_list = _g1->young_list();
1736 size_t eden_bytes = young_list->eden_used_bytes();
1737 size_t survivor_bytes = young_list->survivor_used_bytes();
1738 size_t used_before_gc = _cur_collection_pause_used_at_start_bytes;
1739 size_t used = _g1->used();
1740 size_t capacity = _g1->capacity();
1741 size_t eden_capacity =
1742 (_young_list_target_length * HeapRegion::GrainBytes) - survivor_bytes;
1743
1744 gclog_or_tty->print_cr(
1745 " [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
1746 "Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
1747 "Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
1748 EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
1749 EXT_SIZE_PARAMS(_eden_bytes_before_gc),
1750 EXT_SIZE_PARAMS(_prev_eden_capacity),
1751 EXT_SIZE_PARAMS(eden_bytes),
1752 EXT_SIZE_PARAMS(eden_capacity),
1753 EXT_SIZE_PARAMS(_survivor_bytes_before_gc),
1754 EXT_SIZE_PARAMS(survivor_bytes),
1755 EXT_SIZE_PARAMS(used_before_gc),
1756 EXT_SIZE_PARAMS(_capacity_before_gc),
1757 EXT_SIZE_PARAMS(used),
1758 EXT_SIZE_PARAMS(capacity));
1759
1760 _prev_eden_capacity = eden_capacity;
1761 } else if (PrintGC) {
1762 _g1->print_size_transition(gclog_or_tty,
1763 _cur_collection_pause_used_at_start_bytes,
1764 _g1->used(), _g1->capacity());
1765 }
1766 }
1767
1768 // <NEW PREDICTION>
1769
1770 void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
1771 double update_rs_processed_buffers,
1772 double goal_ms) {
1773 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
1774 ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
1775
1776 if (G1UseAdaptiveConcRefinement) {
1777 const int k_gy = 3, k_gr = 6;
1778 const double inc_k = 1.1, dec_k = 0.9;
1779
1780 int g = cg1r->green_zone();
1781 if (update_rs_time > goal_ms) {
1782 g = (int)(g * dec_k); // Can become 0, that's OK. That would mean a mutator-only processing.
1783 } else {
1784 if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
1785 g = (int)MAX2(g * inc_k, g + 1.0);
1786 }
1787 }
1788 // Change the refinement threads params
1789 cg1r->set_green_zone(g);
1790 cg1r->set_yellow_zone(g * k_gy);
1791 cg1r->set_red_zone(g * k_gr);
1792 cg1r->reinitialize_threads();
1793
1794 int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
1795 int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
1796 cg1r->yellow_zone());
1797 // Change the barrier params
1798 dcqs.set_process_completed_threshold(processing_threshold);
1799 dcqs.set_max_completed_queue(cg1r->red_zone());
1800 }
1801
1802 int curr_queue_size = dcqs.completed_buffers_num();
1803 if (curr_queue_size >= cg1r->yellow_zone()) {
1804 dcqs.set_completed_queue_padding(curr_queue_size);
1805 } else {
1806 dcqs.set_completed_queue_padding(0);
1807 }
1808 dcqs.notify_if_necessary();
1809 }
1810
1811 double
1812 G1CollectorPolicy::
1813 predict_young_collection_elapsed_time_ms(size_t adjustment) {
1814 guarantee( adjustment == 0 || adjustment == 1, "invariant" );
1815
1816 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1817 size_t young_num = g1h->young_list()->length();
1818 if (young_num == 0)
1819 return 0.0;
1820
1821 young_num += adjustment;
1822 size_t pending_cards = predict_pending_cards();
1823 size_t rs_lengths = g1h->young_list()->sampled_rs_lengths() +
1824 predict_rs_length_diff();
1825 size_t card_num;
1826 if (full_young_gcs())
1827 card_num = predict_young_card_num(rs_lengths);
1828 else
1829 card_num = predict_non_young_card_num(rs_lengths);
1830 size_t young_byte_size = young_num * HeapRegion::GrainBytes;
1831 double accum_yg_surv_rate =
1832 _short_lived_surv_rate_group->accum_surv_rate(adjustment);
1833
1834 size_t bytes_to_copy =
1835 (size_t) (accum_yg_surv_rate * (double) HeapRegion::GrainBytes);
1836
1837 return
1838 predict_rs_update_time_ms(pending_cards) +
1839 predict_rs_scan_time_ms(card_num) +
1840 predict_object_copy_time_ms(bytes_to_copy) +
1841 predict_young_other_time_ms(young_num) +
1842 predict_constant_other_time_ms();
1843 }
1844
1845 double
1846 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
1847 size_t rs_length = predict_rs_length_diff();
1848 size_t card_num;
1849 if (full_young_gcs())
1850 card_num = predict_young_card_num(rs_length);
1851 else
1852 card_num = predict_non_young_card_num(rs_length);
1853 return predict_base_elapsed_time_ms(pending_cards, card_num);
1854 }
1855
1856 double
1857 G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
1858 size_t scanned_cards) {
1859 return
1860 predict_rs_update_time_ms(pending_cards) +
1861 predict_rs_scan_time_ms(scanned_cards) +
1862 predict_constant_other_time_ms();
1863 }
1864
1865 double
1866 G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
1867 bool young) {
1868 size_t rs_length = hr->rem_set()->occupied();
1869 size_t card_num;
1870 if (full_young_gcs())
1871 card_num = predict_young_card_num(rs_length);
1872 else
1873 card_num = predict_non_young_card_num(rs_length);
1874 size_t bytes_to_copy = predict_bytes_to_copy(hr);
1875
1876 double region_elapsed_time_ms =
1877 predict_rs_scan_time_ms(card_num) +
1878 predict_object_copy_time_ms(bytes_to_copy);
1879
1880 if (young)
1881 region_elapsed_time_ms += predict_young_other_time_ms(1);
1882 else
1883 region_elapsed_time_ms += predict_non_young_other_time_ms(1);
1884
1885 return region_elapsed_time_ms;
1886 }
1887
1888 size_t
1889 G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
1890 size_t bytes_to_copy;
1891 if (hr->is_marked())
1892 bytes_to_copy = hr->max_live_bytes();
1893 else {
1894 guarantee( hr->is_young() && hr->age_in_surv_rate_group() != -1,
1895 "invariant" );
1896 int age = hr->age_in_surv_rate_group();
1897 double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
1898 bytes_to_copy = (size_t) ((double) hr->used() * yg_surv_rate);
1899 }
1900
1901 return bytes_to_copy;
1902 }
1903
1904 void
1905 G1CollectorPolicy::start_recording_regions() {
1906 _recorded_rs_lengths = 0;
1907 _recorded_young_regions = 0;
1908 _recorded_non_young_regions = 0;
1909
1910 #if PREDICTIONS_VERBOSE
1911 _recorded_marked_bytes = 0;
1912 _recorded_young_bytes = 0;
1913 _predicted_bytes_to_copy = 0;
1914 _predicted_rs_lengths = 0;
1915 _predicted_cards_scanned = 0;
1916 #endif // PREDICTIONS_VERBOSE
1917 }
1918
1919 void
1920 G1CollectorPolicy::record_cset_region_info(HeapRegion* hr, bool young) {
1921 #if PREDICTIONS_VERBOSE
1922 if (!young) {
1923 _recorded_marked_bytes += hr->max_live_bytes();
1924 }
1925 _predicted_bytes_to_copy += predict_bytes_to_copy(hr);
1926 #endif // PREDICTIONS_VERBOSE
1927
1928 size_t rs_length = hr->rem_set()->occupied();
1929 _recorded_rs_lengths += rs_length;
1930 }
1931
1932 void
1933 G1CollectorPolicy::record_non_young_cset_region(HeapRegion* hr) {
1934 assert(!hr->is_young(), "should not call this");
1935 ++_recorded_non_young_regions;
1936 record_cset_region_info(hr, false);
1937 }
1938
1939 void
1940 G1CollectorPolicy::set_recorded_young_regions(size_t n_regions) {
1941 _recorded_young_regions = n_regions;
1942 }
1943
1944 void G1CollectorPolicy::set_recorded_young_bytes(size_t bytes) {
1945 #if PREDICTIONS_VERBOSE
1946 _recorded_young_bytes = bytes;
1947 #endif // PREDICTIONS_VERBOSE
1948 }
1949
1950 void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
1951 _recorded_rs_lengths = rs_lengths;
1952 }
1953
1954 void G1CollectorPolicy::set_predicted_bytes_to_copy(size_t bytes) {
1955 _predicted_bytes_to_copy = bytes;
1956 }
1957
1958 void
1959 G1CollectorPolicy::end_recording_regions() {
1960 // The _predicted_pause_time_ms field is referenced in code
1961 // not under PREDICTIONS_VERBOSE. Let's initialize it.
1962 _predicted_pause_time_ms = -1.0;
1963
1964 #if PREDICTIONS_VERBOSE
1965 _predicted_pending_cards = predict_pending_cards();
1966 _predicted_rs_lengths = _recorded_rs_lengths + predict_rs_length_diff();
1967 if (full_young_gcs())
1968 _predicted_cards_scanned += predict_young_card_num(_predicted_rs_lengths);
1969 else
1970 _predicted_cards_scanned +=
1971 predict_non_young_card_num(_predicted_rs_lengths);
1972 _recorded_region_num = _recorded_young_regions + _recorded_non_young_regions;
1973
1974 _predicted_rs_update_time_ms =
1975 predict_rs_update_time_ms(_g1->pending_card_num());
1976 _predicted_rs_scan_time_ms =
1977 predict_rs_scan_time_ms(_predicted_cards_scanned);
1978 _predicted_object_copy_time_ms =
1979 predict_object_copy_time_ms(_predicted_bytes_to_copy);
1980 _predicted_constant_other_time_ms =
1981 predict_constant_other_time_ms();
1982 _predicted_young_other_time_ms =
1983 predict_young_other_time_ms(_recorded_young_regions);
1984 _predicted_non_young_other_time_ms =
1985 predict_non_young_other_time_ms(_recorded_non_young_regions);
1986
1987 _predicted_pause_time_ms =
1988 _predicted_rs_update_time_ms +
1989 _predicted_rs_scan_time_ms +
1990 _predicted_object_copy_time_ms +
1991 _predicted_constant_other_time_ms +
1992 _predicted_young_other_time_ms +
1993 _predicted_non_young_other_time_ms;
1994 #endif // PREDICTIONS_VERBOSE
1995 }
1996
1997 void G1CollectorPolicy::check_if_region_is_too_expensive(double
1998 predicted_time_ms) {
1999 // I don't think we need to do this when in young GC mode since
2000 // marking will be initiated next time we hit the soft limit anyway...
2001 if (predicted_time_ms > _expensive_region_limit_ms) {
2002 ergo_verbose2(ErgoPartiallyYoungGCs,
2003 "request partially-young GCs end",
2004 ergo_format_reason("predicted region time higher than threshold")
2005 ergo_format_ms("predicted region time")
2006 ergo_format_ms("threshold"),
2007 predicted_time_ms, _expensive_region_limit_ms);
2008 // no point in doing another partial one
2009 _should_revert_to_full_young_gcs = true;
2010 }
2011 }
2012
2013 // </NEW PREDICTION>
2014
2015
2016 void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
2017 double elapsed_ms) {
2018 _recent_gc_times_ms->add(elapsed_ms);
2019 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
2020 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
2021 }
2022
2023 double G1CollectorPolicy::recent_avg_time_for_pauses_ms() {
2024 if (_recent_pause_times_ms->num() == 0) {
2025 return (double) MaxGCPauseMillis;
2026 }
2027 return _recent_pause_times_ms->avg();
2028 }
2029
2030 double G1CollectorPolicy::recent_avg_time_for_rs_scan_ms() {
2031 if (_recent_rs_scan_times_ms->num() == 0) {
2032 return (double)MaxGCPauseMillis/3.0;
2033 }
2034 return _recent_rs_scan_times_ms->avg();
2035 }
2036
2037 int G1CollectorPolicy::number_of_recent_gcs() {
2038 assert(_recent_rs_scan_times_ms->num() ==
2039 _recent_pause_times_ms->num(), "Sequence out of sync");
2040 assert(_recent_pause_times_ms->num() ==
2041 _recent_CS_bytes_used_before->num(), "Sequence out of sync");
2042 assert(_recent_CS_bytes_used_before->num() ==
2043 _recent_CS_bytes_surviving->num(), "Sequence out of sync");
2044
2045 return _recent_pause_times_ms->num();
2046 }
2047
2048 double G1CollectorPolicy::recent_avg_survival_fraction() {
2049 return recent_avg_survival_fraction_work(_recent_CS_bytes_surviving,
2050 _recent_CS_bytes_used_before);
2051 }
2052
2053 double G1CollectorPolicy::last_survival_fraction() {
2054 return last_survival_fraction_work(_recent_CS_bytes_surviving,
2055 _recent_CS_bytes_used_before);
2056 }
2057
2058 double
2059 G1CollectorPolicy::recent_avg_survival_fraction_work(TruncatedSeq* surviving,
2060 TruncatedSeq* before) {
2061 assert(surviving->num() == before->num(), "Sequence out of sync");
2062 if (before->sum() > 0.0) {
2063 double recent_survival_rate = surviving->sum() / before->sum();
2064 // We exempt parallel collection from this check because Alloc Buffer
2065 // fragmentation can produce negative collections.
2066 // Further, we're now always doing parallel collection. But I'm still
2067 // leaving this here as a placeholder for a more precise assertion later.
2068 // (DLD, 10/05.)
2069 assert((true || G1CollectedHeap::use_parallel_gc_threads()) ||
2070 _g1->evacuation_failed() ||
2071 recent_survival_rate <= 1.0, "Or bad frac");
2072 return recent_survival_rate;
2073 } else {
2074 return 1.0; // Be conservative.
2075 }
2076 }
2077
2078 double
2079 G1CollectorPolicy::last_survival_fraction_work(TruncatedSeq* surviving,
2080 TruncatedSeq* before) {
2081 assert(surviving->num() == before->num(), "Sequence out of sync");
2082 if (surviving->num() > 0 && before->last() > 0.0) {
2083 double last_survival_rate = surviving->last() / before->last();
2084 // We exempt parallel collection from this check because Alloc Buffer
2085 // fragmentation can produce negative collections.
2086 // Further, we're now always doing parallel collection. But I'm still
2087 // leaving this here as a placeholder for a more precise assertion later.
2088 // (DLD, 10/05.)
2089 assert((true || G1CollectedHeap::use_parallel_gc_threads()) ||
2090 last_survival_rate <= 1.0, "Or bad frac");
2091 return last_survival_rate;
2092 } else {
2093 return 1.0;
2094 }
2095 }
2096
2097 static const int survival_min_obs = 5;
2098 static double survival_min_obs_limits[] = { 0.9, 0.7, 0.5, 0.3, 0.1 };
2099 static const double min_survival_rate = 0.1;
2100
2101 double
2102 G1CollectorPolicy::conservative_avg_survival_fraction_work(double avg,
2103 double latest) {
2104 double res = avg;
2105 if (number_of_recent_gcs() < survival_min_obs) {
2106 res = MAX2(res, survival_min_obs_limits[number_of_recent_gcs()]);
2107 }
2108 res = MAX2(res, latest);
2109 res = MAX2(res, min_survival_rate);
2110 // In the parallel case, LAB fragmentation can produce "negative
2111 // collections"; so can evac failure. Cap at 1.0
2112 res = MIN2(res, 1.0);
2113 return res;
2114 }
2115
2116 size_t G1CollectorPolicy::expansion_amount() {
2117 double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
2118 double threshold = _gc_overhead_perc;
2119 if (recent_gc_overhead > threshold) {
2120 // We will double the existing space, or take
2121 // G1ExpandByPercentOfAvailable % of the available expansion
2122 // space, whichever is smaller, bounded below by a minimum
2123 // expansion (unless that's all that's left.)
2124 const size_t min_expand_bytes = 1*M;
2125 size_t reserved_bytes = _g1->max_capacity();
2126 size_t committed_bytes = _g1->capacity();
2127 size_t uncommitted_bytes = reserved_bytes - committed_bytes;
2128 size_t expand_bytes;
2129 size_t expand_bytes_via_pct =
2130 uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
2131 expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
2132 expand_bytes = MAX2(expand_bytes, min_expand_bytes);
2133 expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
2134
2135 ergo_verbose5(ErgoHeapSizing,
2136 "attempt heap expansion",
2137 ergo_format_reason("recent GC overhead higher than "
2138 "threshold after GC")
2139 ergo_format_perc("recent GC overhead")
2140 ergo_format_perc("threshold")
2141 ergo_format_byte("uncommitted")
2142 ergo_format_byte_perc("calculated expansion amount"),
2143 recent_gc_overhead, threshold,
2144 uncommitted_bytes,
2145 expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
2146
2147 return expand_bytes;
2148 } else {
2149 return 0;
2150 }
2151 }
2152
2153 void G1CollectorPolicy::note_start_of_mark_thread() {
2154 _mark_thread_startup_sec = os::elapsedTime();
2155 }
2156
2157 class CountCSClosure: public HeapRegionClosure {
2158 G1CollectorPolicy* _g1_policy;
2159 public:
2160 CountCSClosure(G1CollectorPolicy* g1_policy) :
2161 _g1_policy(g1_policy) {}
2162 bool doHeapRegion(HeapRegion* r) {
2163 _g1_policy->_bytes_in_collection_set_before_gc += r->used();
2164 return false;
2165 }
2166 };
2167
2168 void G1CollectorPolicy::count_CS_bytes_used() {
2169 CountCSClosure cs_closure(this);
2170 _g1->collection_set_iterate(&cs_closure);
2171 }
2172
2173 void G1CollectorPolicy::print_summary (int level,
2174 const char* str,
2175 NumberSeq* seq) const {
2176 double sum = seq->sum();
2177 LineBuffer(level + 1).append_and_print_cr("%-24s = %8.2lf s (avg = %8.2lf ms)",
2178 str, sum / 1000.0, seq->avg());
2179 }
2180
2181 void G1CollectorPolicy::print_summary_sd (int level,
2182 const char* str,
2183 NumberSeq* seq) const {
2184 print_summary(level, str, seq);
2185 LineBuffer(level + 6).append_and_print_cr("(num = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
2186 seq->num(), seq->sd(), seq->maximum());
2187 }
2188
2189 void G1CollectorPolicy::check_other_times(int level,
2190 NumberSeq* other_times_ms,
2191 NumberSeq* calc_other_times_ms) const {
2192 bool should_print = false;
2193 LineBuffer buf(level + 2);
2194
2195 double max_sum = MAX2(fabs(other_times_ms->sum()),
2196 fabs(calc_other_times_ms->sum()));
2197 double min_sum = MIN2(fabs(other_times_ms->sum()),
2198 fabs(calc_other_times_ms->sum()));
2199 double sum_ratio = max_sum / min_sum;
2200 if (sum_ratio > 1.1) {
2201 should_print = true;
2202 buf.append_and_print_cr("## CALCULATED OTHER SUM DOESN'T MATCH RECORDED ###");
2203 }
2204
2205 double max_avg = MAX2(fabs(other_times_ms->avg()),
2206 fabs(calc_other_times_ms->avg()));
2207 double min_avg = MIN2(fabs(other_times_ms->avg()),
2208 fabs(calc_other_times_ms->avg()));
2209 double avg_ratio = max_avg / min_avg;
2210 if (avg_ratio > 1.1) {
2211 should_print = true;
2212 buf.append_and_print_cr("## CALCULATED OTHER AVG DOESN'T MATCH RECORDED ###");
2213 }
2214
2215 if (other_times_ms->sum() < -0.01) {
2216 buf.append_and_print_cr("## RECORDED OTHER SUM IS NEGATIVE ###");
2217 }
2218
2219 if (other_times_ms->avg() < -0.01) {
2220 buf.append_and_print_cr("## RECORDED OTHER AVG IS NEGATIVE ###");
2221 }
2222
2223 if (calc_other_times_ms->sum() < -0.01) {
2224 should_print = true;
2225 buf.append_and_print_cr("## CALCULATED OTHER SUM IS NEGATIVE ###");
2226 }
2227
2228 if (calc_other_times_ms->avg() < -0.01) {
2229 should_print = true;
2230 buf.append_and_print_cr("## CALCULATED OTHER AVG IS NEGATIVE ###");
2231 }
2232
2233 if (should_print)
2234 print_summary(level, "Other(Calc)", calc_other_times_ms);
2235 }
2236
2237 void G1CollectorPolicy::print_summary(PauseSummary* summary) const {
2238 bool parallel = G1CollectedHeap::use_parallel_gc_threads();
2239 MainBodySummary* body_summary = summary->main_body_summary();
2240 if (summary->get_total_seq()->num() > 0) {
2241 print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
2242 if (body_summary != NULL) {
2243 print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
2244 if (parallel) {
2245 print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
2246 print_summary(2, "Update RS", body_summary->get_update_rs_seq());
2247 print_summary(2, "Ext Root Scanning",
2248 body_summary->get_ext_root_scan_seq());
2249 print_summary(2, "Mark Stack Scanning",
2250 body_summary->get_mark_stack_scan_seq());
2251 print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
2252 print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
2253 print_summary(2, "Termination", body_summary->get_termination_seq());
2254 print_summary(2, "Other", body_summary->get_parallel_other_seq());
2255 {
2256 NumberSeq* other_parts[] = {
2257 body_summary->get_update_rs_seq(),
2258 body_summary->get_ext_root_scan_seq(),
2259 body_summary->get_mark_stack_scan_seq(),
2260 body_summary->get_scan_rs_seq(),
2261 body_summary->get_obj_copy_seq(),
2262 body_summary->get_termination_seq()
2263 };
2264 NumberSeq calc_other_times_ms(body_summary->get_parallel_seq(),
2265 6, other_parts);
2266 check_other_times(2, body_summary->get_parallel_other_seq(),
2267 &calc_other_times_ms);
2268 }
2269 print_summary(1, "Mark Closure", body_summary->get_mark_closure_seq());
2270 print_summary(1, "Clear CT", body_summary->get_clear_ct_seq());
2271 } else {
2272 print_summary(1, "Update RS", body_summary->get_update_rs_seq());
2273 print_summary(1, "Ext Root Scanning",
2274 body_summary->get_ext_root_scan_seq());
2275 print_summary(1, "Mark Stack Scanning",
2276 body_summary->get_mark_stack_scan_seq());
2277 print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
2278 print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
2279 }
2280 }
2281 print_summary(1, "Other", summary->get_other_seq());
2282 {
2283 if (body_summary != NULL) {
2284 NumberSeq calc_other_times_ms;
2285 if (parallel) {
2286 // parallel
2287 NumberSeq* other_parts[] = {
2288 body_summary->get_satb_drain_seq(),
2289 body_summary->get_parallel_seq(),
2290 body_summary->get_clear_ct_seq()
2291 };
2292 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2293 3, other_parts);
2294 } else {
2295 // serial
2296 NumberSeq* other_parts[] = {
2297 body_summary->get_satb_drain_seq(),
2298 body_summary->get_update_rs_seq(),
2299 body_summary->get_ext_root_scan_seq(),
2300 body_summary->get_mark_stack_scan_seq(),
2301 body_summary->get_scan_rs_seq(),
2302 body_summary->get_obj_copy_seq()
2303 };
2304 calc_other_times_ms = NumberSeq(summary->get_total_seq(),
2305 6, other_parts);
2306 }
2307 check_other_times(1, summary->get_other_seq(), &calc_other_times_ms);
2308 }
2309 }
2310 } else {
2311 LineBuffer(1).append_and_print_cr("none");
2312 }
2313 LineBuffer(0).append_and_print_cr("");
2314 }
2315
2316 void G1CollectorPolicy::print_tracing_info() const {
2317 if (TraceGen0Time) {
2318 gclog_or_tty->print_cr("ALL PAUSES");
2319 print_summary_sd(0, "Total", _all_pause_times_ms);
2320 gclog_or_tty->print_cr("");
2321 gclog_or_tty->print_cr("");
2322 gclog_or_tty->print_cr(" Full Young GC Pauses: %8d", _full_young_pause_num);
2323 gclog_or_tty->print_cr(" Partial Young GC Pauses: %8d", _partial_young_pause_num);
2324 gclog_or_tty->print_cr("");
2325
2326 gclog_or_tty->print_cr("EVACUATION PAUSES");
2327 print_summary(_summary);
2328
2329 gclog_or_tty->print_cr("MISC");
2330 print_summary_sd(0, "Stop World", _all_stop_world_times_ms);
2331 print_summary_sd(0, "Yields", _all_yield_times_ms);
2332 for (int i = 0; i < _aux_num; ++i) {
2333 if (_all_aux_times_ms[i].num() > 0) {
2334 char buffer[96];
2335 sprintf(buffer, "Aux%d", i);
2336 print_summary_sd(0, buffer, &_all_aux_times_ms[i]);
2337 }
2338 }
2339
2340 size_t all_region_num = _region_num_young + _region_num_tenured;
2341 gclog_or_tty->print_cr(" New Regions %8d, Young %8d (%6.2lf%%), "
2342 "Tenured %8d (%6.2lf%%)",
2343 all_region_num,
2344 _region_num_young,
2345 (double) _region_num_young / (double) all_region_num * 100.0,
2346 _region_num_tenured,
2347 (double) _region_num_tenured / (double) all_region_num * 100.0);
2348 }
2349 if (TraceGen1Time) {
2350 if (_all_full_gc_times_ms->num() > 0) {
2351 gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
2352 _all_full_gc_times_ms->num(),
2353 _all_full_gc_times_ms->sum() / 1000.0);
2354 gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times_ms->avg());
2355 gclog_or_tty->print_cr(" [std. dev = %8.2f ms, max = %8.2f ms]",
2356 _all_full_gc_times_ms->sd(),
2357 _all_full_gc_times_ms->maximum());
2358 }
2359 }
2360 }
2361
2362 void G1CollectorPolicy::print_yg_surv_rate_info() const {
2363 #ifndef PRODUCT
2364 _short_lived_surv_rate_group->print_surv_rate_summary();
2365 // add this call for any other surv rate groups
2366 #endif // PRODUCT
2367 }
2368
2369 void G1CollectorPolicy::update_region_num(bool young) {
2370 if (young) {
2371 ++_region_num_young;
2372 } else {
2373 ++_region_num_tenured;
2374 }
2375 }
2376
2377 #ifndef PRODUCT
2378 // for debugging, bit of a hack...
2379 static char*
2380 region_num_to_mbs(int length) {
2381 static char buffer[64];
2382 double bytes = (double) (length * HeapRegion::GrainBytes);
2383 double mbs = bytes / (double) (1024 * 1024);
2384 sprintf(buffer, "%7.2lfMB", mbs);
2385 return buffer;
2386 }
2387 #endif // PRODUCT
2388
2389 size_t G1CollectorPolicy::max_regions(int purpose) {
2390 switch (purpose) {
2391 case GCAllocForSurvived:
2392 return _max_survivor_regions;
2393 case GCAllocForTenured:
2394 return REGIONS_UNLIMITED;
2395 default:
2396 ShouldNotReachHere();
2397 return REGIONS_UNLIMITED;
2398 };
2399 }
2400
2401 void G1CollectorPolicy::update_max_gc_locker_expansion() {
2402 size_t expansion_region_num = 0;
2403 if (GCLockerEdenExpansionPercent > 0) {
2404 double perc = (double) GCLockerEdenExpansionPercent / 100.0;
2405 double expansion_region_num_d = perc * (double) _young_list_target_length;
2406 // We use ceiling so that if expansion_region_num_d is > 0.0 (but
2407 // less than 1.0) we'll get 1.
2408 expansion_region_num = (size_t) ceil(expansion_region_num_d);
2409 } else {
2410 assert(expansion_region_num == 0, "sanity");
2411 }
2412 _young_list_max_length = _young_list_target_length + expansion_region_num;
2413 assert(_young_list_target_length <= _young_list_max_length, "post-condition");
2414 }
2415
2416 // Calculates survivor space parameters.
2417 void G1CollectorPolicy::update_survivors_policy() {
2418 double max_survivor_regions_d =
2419 (double) _young_list_target_length / (double) SurvivorRatio;
2420 // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
2421 // smaller than 1.0) we'll get 1.
2422 _max_survivor_regions = (size_t) ceil(max_survivor_regions_d);
2423
2424 _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(
2425 HeapRegion::GrainWords * _max_survivor_regions);
2426 }
2427
2428 #ifndef PRODUCT
2429 class HRSortIndexIsOKClosure: public HeapRegionClosure {
2430 CollectionSetChooser* _chooser;
2431 public:
2432 HRSortIndexIsOKClosure(CollectionSetChooser* chooser) :
2433 _chooser(chooser) {}
2434
2435 bool doHeapRegion(HeapRegion* r) {
2436 if (!r->continuesHumongous()) {
2437 assert(_chooser->regionProperlyOrdered(r), "Ought to be.");
2438 }
2439 return false;
2440 }
2441 };
2442
2443 bool G1CollectorPolicy_BestRegionsFirst::assertMarkedBytesDataOK() {
2444 HRSortIndexIsOKClosure cl(_collectionSetChooser);
2445 _g1->heap_region_iterate(&cl);
2446 return true;
2447 }
2448 #endif
2449
2450 bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
2451 GCCause::Cause gc_cause) {
2452 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
2453 if (!during_cycle) {
2454 ergo_verbose1(ErgoConcCycles,
2455 "request concurrent cycle initiation",
2456 ergo_format_reason("requested by GC cause")
2457 ergo_format_str("GC cause"),
2458 GCCause::to_string(gc_cause));
2459 set_initiate_conc_mark_if_possible();
2460 return true;
2461 } else {
2462 ergo_verbose1(ErgoConcCycles,
2463 "do not request concurrent cycle initiation",
2464 ergo_format_reason("concurrent cycle already in progress")
2465 ergo_format_str("GC cause"),
2466 GCCause::to_string(gc_cause));
2467 return false;
2468 }
2469 }
2470
2471 void
2472 G1CollectorPolicy::decide_on_conc_mark_initiation() {
2473 // We are about to decide on whether this pause will be an
2474 // initial-mark pause.
2475
2476 // First, during_initial_mark_pause() should not be already set. We
2477 // will set it here if we have to. However, it should be cleared by
2478 // the end of the pause (it's only set for the duration of an
2479 // initial-mark pause).
2480 assert(!during_initial_mark_pause(), "pre-condition");
2481
2482 if (initiate_conc_mark_if_possible()) {
2483 // We had noticed on a previous pause that the heap occupancy has
2484 // gone over the initiating threshold and we should start a
2485 // concurrent marking cycle. So we might initiate one.
2486
2487 bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
2488 if (!during_cycle) {
2489 // The concurrent marking thread is not "during a cycle", i.e.,
2490 // it has completed the last one. So we can go ahead and
2491 // initiate a new cycle.
2492
2493 set_during_initial_mark_pause();
2494
2495 // And we can now clear initiate_conc_mark_if_possible() as
2496 // we've already acted on it.
2497 clear_initiate_conc_mark_if_possible();
2498
2499 ergo_verbose0(ErgoConcCycles,
2500 "initiate concurrent cycle",
2501 ergo_format_reason("concurrent cycle initiation requested"));
2502 } else {
2503 // The concurrent marking thread is still finishing up the
2504 // previous cycle. If we start one right now the two cycles
2505 // overlap. In particular, the concurrent marking thread might
2506 // be in the process of clearing the next marking bitmap (which
2507 // we will use for the next cycle if we start one). Starting a
2508 // cycle now will be bad given that parts of the marking
2509 // information might get cleared by the marking thread. And we
2510 // cannot wait for the marking thread to finish the cycle as it
2511 // periodically yields while clearing the next marking bitmap
2512 // and, if it's in a yield point, it's waiting for us to
2513 // finish. So, at this point we will not start a cycle and we'll
2514 // let the concurrent marking thread complete the last one.
2515 ergo_verbose0(ErgoConcCycles,
2516 "do not initiate concurrent cycle",
2517 ergo_format_reason("concurrent cycle already in progress"));
2518 }
2519 }
2520 }
2521
2522 void
2523 G1CollectorPolicy_BestRegionsFirst::
2524 record_collection_pause_start(double start_time_sec, size_t start_used) {
2525 G1CollectorPolicy::record_collection_pause_start(start_time_sec, start_used);
2526 }
2527
2528 class KnownGarbageClosure: public HeapRegionClosure {
2529 CollectionSetChooser* _hrSorted;
2530
2531 public:
2532 KnownGarbageClosure(CollectionSetChooser* hrSorted) :
2533 _hrSorted(hrSorted)
2534 {}
2535
2536 bool doHeapRegion(HeapRegion* r) {
2537 // We only include humongous regions in collection
2538 // sets when concurrent mark shows that their contained object is
2539 // unreachable.
2540
2541 // Do we have any marking information for this region?
2542 if (r->is_marked()) {
2543 // We don't include humongous regions in collection
2544 // sets because we collect them immediately at the end of a marking
2545 // cycle. We also don't include young regions because we *must*
2546 // include them in the next collection pause.
2547 if (!r->isHumongous() && !r->is_young()) {
2548 _hrSorted->addMarkedHeapRegion(r);
2549 }
2550 }
2551 return false;
2552 }
2553 };
2554
2555 class ParKnownGarbageHRClosure: public HeapRegionClosure {
2556 CollectionSetChooser* _hrSorted;
2557 jint _marked_regions_added;
2558 jint _chunk_size;
2559 jint _cur_chunk_idx;
2560 jint _cur_chunk_end; // Cur chunk [_cur_chunk_idx, _cur_chunk_end)
2561 int _worker;
2562 int _invokes;
2563
2564 void get_new_chunk() {
2565 _cur_chunk_idx = _hrSorted->getParMarkedHeapRegionChunk(_chunk_size);
2566 _cur_chunk_end = _cur_chunk_idx + _chunk_size;
2567 }
2568 void add_region(HeapRegion* r) {
2569 if (_cur_chunk_idx == _cur_chunk_end) {
2570 get_new_chunk();
2571 }
2572 assert(_cur_chunk_idx < _cur_chunk_end, "postcondition");
2573 _hrSorted->setMarkedHeapRegion(_cur_chunk_idx, r);
2574 _marked_regions_added++;
2575 _cur_chunk_idx++;
2576 }
2577
2578 public:
2579 ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
2580 jint chunk_size,
2581 int worker) :
2582 _hrSorted(hrSorted), _chunk_size(chunk_size), _worker(worker),
2583 _marked_regions_added(0), _cur_chunk_idx(0), _cur_chunk_end(0),
2584 _invokes(0)
2585 {}
2586
2587 bool doHeapRegion(HeapRegion* r) {
2588 // We only include humongous regions in collection
2589 // sets when concurrent mark shows that their contained object is
2590 // unreachable.
2591 _invokes++;
2592
2593 // Do we have any marking information for this region?
2594 if (r->is_marked()) {
2595 // We don't include humongous regions in collection
2596 // sets because we collect them immediately at the end of a marking
2597 // cycle.
2598 // We also do not include young regions in collection sets
2599 if (!r->isHumongous() && !r->is_young()) {
2600 add_region(r);
2601 }
2602 }
2603 return false;
2604 }
2605 jint marked_regions_added() { return _marked_regions_added; }
2606 int invokes() { return _invokes; }
2607 };
2608
2609 class ParKnownGarbageTask: public AbstractGangTask {
2610 CollectionSetChooser* _hrSorted;
2611 jint _chunk_size;
2612 G1CollectedHeap* _g1;
2613 public:
2614 ParKnownGarbageTask(CollectionSetChooser* hrSorted, jint chunk_size) :
2615 AbstractGangTask("ParKnownGarbageTask"),
2616 _hrSorted(hrSorted), _chunk_size(chunk_size),
2617 _g1(G1CollectedHeap::heap())
2618 {}
2619
2620 void work(int i) {
2621 ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size, i);
2622 // Back to zero for the claim value.
2623 _g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, i,
2624 HeapRegion::InitialClaimValue);
2625 jint regions_added = parKnownGarbageCl.marked_regions_added();
2626 _hrSorted->incNumMarkedHeapRegions(regions_added);
2627 if (G1PrintParCleanupStats) {
2628 gclog_or_tty->print_cr(" Thread %d called %d times, added %d regions to list.",
2629 i, parKnownGarbageCl.invokes(), regions_added);
2630 }
2631 }
2632 };
2633
2634 void
2635 G1CollectorPolicy_BestRegionsFirst::
2636 record_concurrent_mark_cleanup_end(size_t freed_bytes,
2637 size_t max_live_bytes) {
2638 double start;
2639 if (G1PrintParCleanupStats) start = os::elapsedTime();
2640 record_concurrent_mark_cleanup_end_work1(freed_bytes, max_live_bytes);
2641
2642 _collectionSetChooser->clearMarkedHeapRegions();
2643 double clear_marked_end;
2644 if (G1PrintParCleanupStats) {
2645 clear_marked_end = os::elapsedTime();
2646 gclog_or_tty->print_cr(" clear marked regions + work1: %8.3f ms.",
2647 (clear_marked_end - start)*1000.0);
2648 }
2649 if (G1CollectedHeap::use_parallel_gc_threads()) {
2650 const size_t OverpartitionFactor = 4;
2651 const size_t MinWorkUnit = 8;
2652 const size_t WorkUnit =
2653 MAX2(_g1->n_regions() / (ParallelGCThreads * OverpartitionFactor),
2654 MinWorkUnit);
2655 _collectionSetChooser->prepareForAddMarkedHeapRegionsPar(_g1->n_regions(),
2656 WorkUnit);
2657 ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
2658 (int) WorkUnit);
2659 _g1->workers()->run_task(&parKnownGarbageTask);
2660
2661 assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
2662 "sanity check");
2663 } else {
2664 KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
2665 _g1->heap_region_iterate(&knownGarbagecl);
2666 }
2667 double known_garbage_end;
2668 if (G1PrintParCleanupStats) {
2669 known_garbage_end = os::elapsedTime();
2670 gclog_or_tty->print_cr(" compute known garbage: %8.3f ms.",
2671 (known_garbage_end - clear_marked_end)*1000.0);
2672 }
2673 _collectionSetChooser->sortMarkedHeapRegions();
2674 double sort_end;
2675 if (G1PrintParCleanupStats) {
2676 sort_end = os::elapsedTime();
2677 gclog_or_tty->print_cr(" sorting: %8.3f ms.",
2678 (sort_end - known_garbage_end)*1000.0);
2679 }
2680
2681 record_concurrent_mark_cleanup_end_work2();
2682 double work2_end;
2683 if (G1PrintParCleanupStats) {
2684 work2_end = os::elapsedTime();
2685 gclog_or_tty->print_cr(" work2: %8.3f ms.",
2686 (work2_end - sort_end)*1000.0);
2687 }
2688 }
2689
2690 // Add the heap region at the head of the non-incremental collection set
2691 void G1CollectorPolicy::
2692 add_to_collection_set(HeapRegion* hr) {
2693 assert(_inc_cset_build_state == Active, "Precondition");
2694 assert(!hr->is_young(), "non-incremental add of young region");
2695
2696 if (_g1->mark_in_progress())
2697 _g1->concurrent_mark()->registerCSetRegion(hr);
2698
2699 assert(!hr->in_collection_set(), "should not already be in the CSet");
2700 hr->set_in_collection_set(true);
2701 hr->set_next_in_collection_set(_collection_set);
2702 _collection_set = hr;
2703 _collection_set_size++;
2704 _collection_set_bytes_used_before += hr->used();
2705 _g1->register_region_with_in_cset_fast_test(hr);
2706 }
2707
2708 // Initialize the per-collection-set information
2709 void G1CollectorPolicy::start_incremental_cset_building() {
2710 assert(_inc_cset_build_state == Inactive, "Precondition");
2711
2712 _inc_cset_head = NULL;
2713 _inc_cset_tail = NULL;
2714 _inc_cset_size = 0;
2715 _inc_cset_bytes_used_before = 0;
2716
2717 _inc_cset_young_index = 0;
2718
2719 _inc_cset_max_finger = 0;
2720 _inc_cset_recorded_young_bytes = 0;
2721 _inc_cset_recorded_rs_lengths = 0;
2722 _inc_cset_predicted_elapsed_time_ms = 0;
2723 _inc_cset_predicted_bytes_to_copy = 0;
2724 _inc_cset_build_state = Active;
2725 }
2726
2727 void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
2728 // This routine is used when:
2729 // * adding survivor regions to the incremental cset at the end of an
2730 // evacuation pause,
2731 // * adding the current allocation region to the incremental cset
2732 // when it is retired, and
2733 // * updating existing policy information for a region in the
2734 // incremental cset via young list RSet sampling.
2735 // Therefore this routine may be called at a safepoint by the
2736 // VM thread, or in-between safepoints by mutator threads (when
2737 // retiring the current allocation region) or a concurrent
2738 // refine thread (RSet sampling).
2739
2740 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, true);
2741 size_t used_bytes = hr->used();
2742
2743 _inc_cset_recorded_rs_lengths += rs_length;
2744 _inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
2745
2746 _inc_cset_bytes_used_before += used_bytes;
2747
2748 // Cache the values we have added to the aggregated informtion
2749 // in the heap region in case we have to remove this region from
2750 // the incremental collection set, or it is updated by the
2751 // rset sampling code
2752 hr->set_recorded_rs_length(rs_length);
2753 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
2754
2755 #if PREDICTIONS_VERBOSE
2756 size_t bytes_to_copy = predict_bytes_to_copy(hr);
2757 _inc_cset_predicted_bytes_to_copy += bytes_to_copy;
2758
2759 // Record the number of bytes used in this region
2760 _inc_cset_recorded_young_bytes += used_bytes;
2761
2762 // Cache the values we have added to the aggregated informtion
2763 // in the heap region in case we have to remove this region from
2764 // the incremental collection set, or it is updated by the
2765 // rset sampling code
2766 hr->set_predicted_bytes_to_copy(bytes_to_copy);
2767 #endif // PREDICTIONS_VERBOSE
2768 }
2769
2770 void G1CollectorPolicy::remove_from_incremental_cset_info(HeapRegion* hr) {
2771 // This routine is currently only called as part of the updating of
2772 // existing policy information for regions in the incremental cset that
2773 // is performed by the concurrent refine thread(s) as part of young list
2774 // RSet sampling. Therefore we should not be at a safepoint.
2775
2776 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
2777 assert(hr->is_young(), "it should be");
2778
2779 size_t used_bytes = hr->used();
2780 size_t old_rs_length = hr->recorded_rs_length();
2781 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
2782
2783 // Subtract the old recorded/predicted policy information for
2784 // the given heap region from the collection set info.
2785 _inc_cset_recorded_rs_lengths -= old_rs_length;
2786 _inc_cset_predicted_elapsed_time_ms -= old_elapsed_time_ms;
2787
2788 _inc_cset_bytes_used_before -= used_bytes;
2789
2790 // Clear the values cached in the heap region
2791 hr->set_recorded_rs_length(0);
2792 hr->set_predicted_elapsed_time_ms(0);
2793
2794 #if PREDICTIONS_VERBOSE
2795 size_t old_predicted_bytes_to_copy = hr->predicted_bytes_to_copy();
2796 _inc_cset_predicted_bytes_to_copy -= old_predicted_bytes_to_copy;
2797
2798 // Subtract the number of bytes used in this region
2799 _inc_cset_recorded_young_bytes -= used_bytes;
2800
2801 // Clear the values cached in the heap region
2802 hr->set_predicted_bytes_to_copy(0);
2803 #endif // PREDICTIONS_VERBOSE
2804 }
2805
2806 void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr, size_t new_rs_length) {
2807 // Update the collection set information that is dependent on the new RS length
2808 assert(hr->is_young(), "Precondition");
2809
2810 remove_from_incremental_cset_info(hr);
2811 add_to_incremental_cset_info(hr, new_rs_length);
2812 }
2813
2814 void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
2815 assert( hr->is_young(), "invariant");
2816 assert( hr->young_index_in_cset() == -1, "invariant" );
2817 assert(_inc_cset_build_state == Active, "Precondition");
2818
2819 // We need to clear and set the cached recorded/cached collection set
2820 // information in the heap region here (before the region gets added
2821 // to the collection set). An individual heap region's cached values
2822 // are calculated, aggregated with the policy collection set info,
2823 // and cached in the heap region here (initially) and (subsequently)
2824 // by the Young List sampling code.
2825
2826 size_t rs_length = hr->rem_set()->occupied();
2827 add_to_incremental_cset_info(hr, rs_length);
2828
2829 HeapWord* hr_end = hr->end();
2830 _inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
2831
2832 assert(!hr->in_collection_set(), "invariant");
2833 hr->set_in_collection_set(true);
2834 assert( hr->next_in_collection_set() == NULL, "invariant");
2835
2836 _inc_cset_size++;
2837 _g1->register_region_with_in_cset_fast_test(hr);
2838
2839 hr->set_young_index_in_cset((int) _inc_cset_young_index);
2840 ++_inc_cset_young_index;
2841 }
2842
2843 // Add the region at the RHS of the incremental cset
2844 void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
2845 // We should only ever be appending survivors at the end of a pause
2846 assert( hr->is_survivor(), "Logic");
2847
2848 // Do the 'common' stuff
2849 add_region_to_incremental_cset_common(hr);
2850
2851 // Now add the region at the right hand side
2852 if (_inc_cset_tail == NULL) {
2853 assert(_inc_cset_head == NULL, "invariant");
2854 _inc_cset_head = hr;
2855 } else {
2856 _inc_cset_tail->set_next_in_collection_set(hr);
2857 }
2858 _inc_cset_tail = hr;
2859 }
2860
2861 // Add the region to the LHS of the incremental cset
2862 void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
2863 // Survivors should be added to the RHS at the end of a pause
2864 assert(!hr->is_survivor(), "Logic");
2865
2866 // Do the 'common' stuff
2867 add_region_to_incremental_cset_common(hr);
2868
2869 // Add the region at the left hand side
2870 hr->set_next_in_collection_set(_inc_cset_head);
2871 if (_inc_cset_head == NULL) {
2872 assert(_inc_cset_tail == NULL, "Invariant");
2873 _inc_cset_tail = hr;
2874 }
2875 _inc_cset_head = hr;
2876 }
2877
2878 #ifndef PRODUCT
2879 void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
2880 assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
2881
2882 st->print_cr("\nCollection_set:");
2883 HeapRegion* csr = list_head;
2884 while (csr != NULL) {
2885 HeapRegion* next = csr->next_in_collection_set();
2886 assert(csr->in_collection_set(), "bad CS");
2887 st->print_cr(" [%08x-%08x], t: %08x, P: %08x, N: %08x, C: %08x, "
2888 "age: %4d, y: %d, surv: %d",
2889 csr->bottom(), csr->end(),
2890 csr->top(),
2891 csr->prev_top_at_mark_start(),
2892 csr->next_top_at_mark_start(),
2893 csr->top_at_conc_mark_count(),
2894 csr->age_in_surv_rate_group_cond(),
2895 csr->is_young(),
2896 csr->is_survivor());
2897 csr = next;
2898 }
2899 }
2900 #endif // !PRODUCT
2901
2902 void
2903 G1CollectorPolicy_BestRegionsFirst::choose_collection_set(
2904 double target_pause_time_ms) {
2905 // Set this here - in case we're not doing young collections.
2906 double non_young_start_time_sec = os::elapsedTime();
2907
2908 YoungList* young_list = _g1->young_list();
2909
2910 start_recording_regions();
2911
2912 guarantee(target_pause_time_ms > 0.0,
2913 err_msg("target_pause_time_ms = %1.6lf should be positive",
2914 target_pause_time_ms));
2915 guarantee(_collection_set == NULL, "Precondition");
2916
2917 double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
2918 double predicted_pause_time_ms = base_time_ms;
2919
2920 double time_remaining_ms = target_pause_time_ms - base_time_ms;
2921
2922 ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
2923 "start choosing CSet",
2924 ergo_format_ms("predicted base time")
2925 ergo_format_ms("remaining time")
2926 ergo_format_ms("target pause time"),
2927 base_time_ms, time_remaining_ms, target_pause_time_ms);
2928
2929 // the 10% and 50% values are arbitrary...
2930 double threshold = 0.10 * target_pause_time_ms;
2931 if (time_remaining_ms < threshold) {
2932 double prev_time_remaining_ms = time_remaining_ms;
2933 time_remaining_ms = 0.50 * target_pause_time_ms;
2934 _within_target = false;
2935 ergo_verbose3(ErgoCSetConstruction,
2936 "adjust remaining time",
2937 ergo_format_reason("remaining time lower than threshold")
2938 ergo_format_ms("remaining time")
2939 ergo_format_ms("threshold")
2940 ergo_format_ms("adjusted remaining time"),
2941 prev_time_remaining_ms, threshold, time_remaining_ms);
2942 } else {
2943 _within_target = true;
2944 }
2945
2946 size_t expansion_bytes = _g1->expansion_regions() * HeapRegion::GrainBytes;
2947
2948 HeapRegion* hr;
2949 double young_start_time_sec = os::elapsedTime();
2950
2951 _collection_set_bytes_used_before = 0;
2952 _collection_set_size = 0;
2953 _young_cset_length = 0;
2954 _last_young_gc_full = full_young_gcs() ? true : false;
2955
2956 if (_last_young_gc_full) {
2957 ++_full_young_pause_num;
2958 } else {
2959 ++_partial_young_pause_num;
2960 }
2961
2962 // The young list is laid with the survivor regions from the previous
2963 // pause are appended to the RHS of the young list, i.e.
2964 // [Newly Young Regions ++ Survivors from last pause].
2965
2966 size_t survivor_region_num = young_list->survivor_length();
2967 size_t eden_region_num = young_list->length() - survivor_region_num;
2968 size_t old_region_num = 0;
2969 hr = young_list->first_survivor_region();
2970 while (hr != NULL) {
2971 assert(hr->is_survivor(), "badly formed young list");
2972 hr->set_young();
2973 hr = hr->get_next_young_region();
2974 }
2975
2976 // Clear the fields that point to the survivor list - they are all young now.
2977 young_list->clear_survivors();
2978
2979 if (_g1->mark_in_progress())
2980 _g1->concurrent_mark()->register_collection_set_finger(_inc_cset_max_finger);
2981
2982 _young_cset_length = _inc_cset_young_index;
2983 _collection_set = _inc_cset_head;
2984 _collection_set_size = _inc_cset_size;
2985 _collection_set_bytes_used_before = _inc_cset_bytes_used_before;
2986 time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms;
2987 predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
2988
2989 ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
2990 "add young regions to CSet",
2991 ergo_format_region("eden")
2992 ergo_format_region("survivors")
2993 ergo_format_ms("predicted young region time"),
2994 eden_region_num, survivor_region_num,
2995 _inc_cset_predicted_elapsed_time_ms);
2996
2997 // The number of recorded young regions is the incremental
2998 // collection set's current size
2999 set_recorded_young_regions(_inc_cset_size);
3000 set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
3001 set_recorded_young_bytes(_inc_cset_recorded_young_bytes);
3002 #if PREDICTIONS_VERBOSE
3003 set_predicted_bytes_to_copy(_inc_cset_predicted_bytes_to_copy);
3004 #endif // PREDICTIONS_VERBOSE
3005
3006 assert(_inc_cset_size == young_list->length(), "Invariant");
3007
3008 double young_end_time_sec = os::elapsedTime();
3009 _recorded_young_cset_choice_time_ms =
3010 (young_end_time_sec - young_start_time_sec) * 1000.0;
3011
3012 // We are doing young collections so reset this.
3013 non_young_start_time_sec = young_end_time_sec;
3014
3015 if (!full_young_gcs()) {
3016 bool should_continue = true;
3017 NumberSeq seq;
3018 double avg_prediction = 100000000000000000.0; // something very large
3019
3020 size_t prev_collection_set_size = _collection_set_size;
3021 double prev_predicted_pause_time_ms = predicted_pause_time_ms;
3022 do {
3023 hr = _collectionSetChooser->getNextMarkedRegion(time_remaining_ms,
3024 avg_prediction);
3025 if (hr != NULL) {
3026 double predicted_time_ms = predict_region_elapsed_time_ms(hr, false);
3027 time_remaining_ms -= predicted_time_ms;
3028 predicted_pause_time_ms += predicted_time_ms;
3029 add_to_collection_set(hr);
3030 record_non_young_cset_region(hr);
3031 seq.add(predicted_time_ms);
3032 avg_prediction = seq.avg() + seq.sd();
3033 }
3034
3035 should_continue = true;
3036 if (hr == NULL) {
3037 // No need for an ergo verbose message here,
3038 // getNextMarkRegion() does this when it returns NULL.
3039 should_continue = false;
3040 } else {
3041 if (adaptive_young_list_length()) {
3042 if (time_remaining_ms < 0.0) {
3043 ergo_verbose1(ErgoCSetConstruction,
3044 "stop adding old regions to CSet",
3045 ergo_format_reason("remaining time is lower than 0")
3046 ergo_format_ms("remaining time"),
3047 time_remaining_ms);
3048 should_continue = false;
3049 }
3050 } else {
3051 if (_collection_set_size >= _young_list_fixed_length) {
3052 ergo_verbose2(ErgoCSetConstruction,
3053 "stop adding old regions to CSet",
3054 ergo_format_reason("CSet length reached target")
3055 ergo_format_region("CSet")
3056 ergo_format_region("young target"),
3057 _collection_set_size, _young_list_fixed_length);
3058 should_continue = false;
3059 }
3060 }
3061 }
3062 } while (should_continue);
3063
3064 if (!adaptive_young_list_length() &&
3065 _collection_set_size < _young_list_fixed_length) {
3066 ergo_verbose2(ErgoCSetConstruction,
3067 "request partially-young GCs end",
3068 ergo_format_reason("CSet length lower than target")
3069 ergo_format_region("CSet")
3070 ergo_format_region("young target"),
3071 _collection_set_size, _young_list_fixed_length);
3072 _should_revert_to_full_young_gcs = true;
3073 }
3074
3075 old_region_num = _collection_set_size - prev_collection_set_size;
3076
3077 ergo_verbose2(ErgoCSetConstruction | ErgoHigh,
3078 "add old regions to CSet",
3079 ergo_format_region("old")
3080 ergo_format_ms("predicted old region time"),
3081 old_region_num,
3082 predicted_pause_time_ms - prev_predicted_pause_time_ms);
3083 }
3084
3085 stop_incremental_cset_building();
3086
3087 count_CS_bytes_used();
3088
3089 end_recording_regions();
3090
3091 ergo_verbose5(ErgoCSetConstruction,
3092 "finish choosing CSet",
3093 ergo_format_region("eden")
3094 ergo_format_region("survivors")
3095 ergo_format_region("old")
3096 ergo_format_ms("predicted pause time")
3097 ergo_format_ms("target pause time"),
3098 eden_region_num, survivor_region_num, old_region_num,
3099 predicted_pause_time_ms, target_pause_time_ms);
3100
3101 double non_young_end_time_sec = os::elapsedTime();
3102 _recorded_non_young_cset_choice_time_ms =
3103 (non_young_end_time_sec - non_young_start_time_sec) * 1000.0;
3104 }
3105
3106 void G1CollectorPolicy_BestRegionsFirst::record_full_collection_end() {
3107 G1CollectorPolicy::record_full_collection_end();
3108 _collectionSetChooser->updateAfterFullCollection();
3109 }
3110
3111 void G1CollectorPolicy_BestRegionsFirst::
3112 record_collection_pause_end() {
3113 G1CollectorPolicy::record_collection_pause_end();
3114 assert(assertMarkedBytesDataOK(), "Marked regions not OK at pause end.");
3115 }