1 /*
2 * Copyright (c) 2002, 2015, 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/parallel/parallelScavengeHeap.hpp"
27 #include "gc/parallel/psAdaptiveSizePolicy.hpp"
28 #include "gc/parallel/psGCAdaptivePolicyCounters.hpp"
29 #include "gc/parallel/psScavenge.hpp"
30 #include "gc/shared/collectorPolicy.hpp"
31 #include "gc/shared/gcCause.hpp"
32 #include "gc/shared/gcPolicyCounters.hpp"
33 #include "runtime/timer.hpp"
34 #include "utilities/top.hpp"
35
36 #include <math.h>
37
38 PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size,
39 size_t init_promo_size,
40 size_t init_survivor_size,
41 size_t space_alignment,
42 double gc_pause_goal_sec,
43 double gc_minor_pause_goal_sec,
44 uint gc_cost_ratio) :
45 AdaptiveSizePolicy(init_eden_size,
46 init_promo_size,
47 init_survivor_size,
48 gc_pause_goal_sec,
49 gc_cost_ratio),
50 _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin / 100.0),
51 _space_alignment(space_alignment),
52 _live_at_last_full_gc(init_promo_size),
53 _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec),
54 _latest_major_mutator_interval_seconds(0),
55 _young_gen_change_for_major_pause_count(0)
56 {
57 // Sizing policy statistics
58 _avg_major_pause =
59 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
60 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
61 _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
62
63 _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
64 _major_pause_old_estimator =
65 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
66 _major_pause_young_estimator =
67 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
68 _major_collection_estimator =
69 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
70
71 _young_gen_size_increment_supplement = YoungGenerationSizeSupplement;
72 _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement;
73
74 // Start the timers
75 _major_timer.start();
76
77 _old_gen_policy_is_ready = false;
78 }
79
80 size_t PSAdaptiveSizePolicy::calculate_free_based_on_live(size_t live, uintx ratio_as_percentage) {
81 // We want to calculate how much free memory there can be based on the
82 // amount of live data currently in the old gen. Using the formula:
83 // ratio * (free + live) = free
84 // Some equation solving later we get:
85 // free = (live * ratio) / (1 - ratio)
86
87 const double ratio = ratio_as_percentage / 100.0;
88 const double ratio_inverse = 1.0 - ratio;
89 const double tmp = live * ratio;
90 size_t free = (size_t)(tmp / ratio_inverse);
91
92 return free;
93 }
94
95 size_t PSAdaptiveSizePolicy::calculated_old_free_size_in_bytes() const {
96 size_t free_size = (size_t)(_promo_size + avg_promoted()->padded_average());
97 size_t live = ParallelScavengeHeap::heap()->old_gen()->used_in_bytes();
98
99 if (MinHeapFreeRatio != 0) {
100 size_t min_free = calculate_free_based_on_live(live, MinHeapFreeRatio);
101 free_size = MAX2(free_size, min_free);
102 }
103
104 if (MaxHeapFreeRatio != 100) {
105 size_t max_free = calculate_free_based_on_live(live, MaxHeapFreeRatio);
106 free_size = MIN2(max_free, free_size);
107 }
108
109 return free_size;
110 }
111
112 void PSAdaptiveSizePolicy::major_collection_begin() {
113 // Update the interval time
114 _major_timer.stop();
115 // Save most recent collection time
116 _latest_major_mutator_interval_seconds = _major_timer.seconds();
117 _major_timer.reset();
118 _major_timer.start();
119 }
120
121 void PSAdaptiveSizePolicy::update_minor_pause_old_estimator(
122 double minor_pause_in_ms) {
123 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
124 _minor_pause_old_estimator->update(promo_size_in_mbytes,
125 minor_pause_in_ms);
126 }
127
128 void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live,
129 GCCause::Cause gc_cause) {
130 // Update the pause time.
131 _major_timer.stop();
132
133 if (should_update_promo_stats(gc_cause)) {
134 double major_pause_in_seconds = _major_timer.seconds();
135 double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS;
136
137 // Sample for performance counter
138 _avg_major_pause->sample(major_pause_in_seconds);
139
140 // Cost of collection (unit-less)
141 double collection_cost = 0.0;
142 if ((_latest_major_mutator_interval_seconds > 0.0) &&
143 (major_pause_in_seconds > 0.0)) {
144 double interval_in_seconds =
145 _latest_major_mutator_interval_seconds + major_pause_in_seconds;
146 collection_cost =
147 major_pause_in_seconds / interval_in_seconds;
148 avg_major_gc_cost()->sample(collection_cost);
149
150 // Sample for performance counter
151 _avg_major_interval->sample(interval_in_seconds);
152 }
153
154 // Calculate variables used to estimate pause time vs. gen sizes
155 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
156 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
157 _major_pause_old_estimator->update(promo_size_in_mbytes,
158 major_pause_in_ms);
159 _major_pause_young_estimator->update(eden_size_in_mbytes,
160 major_pause_in_ms);
161
162 if (PrintAdaptiveSizePolicy && Verbose) {
163 gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: "
164 "major gc cost: %f average: %f", collection_cost,
165 avg_major_gc_cost()->average());
166 gclog_or_tty->print_cr(" major pause: %f major period %f",
167 major_pause_in_ms,
168 _latest_major_mutator_interval_seconds * MILLIUNITS);
169 }
170
171 // Calculate variable used to estimate collection cost vs. gen sizes
172 assert(collection_cost >= 0.0, "Expected to be non-negative");
173 _major_collection_estimator->update(promo_size_in_mbytes,
174 collection_cost);
175 }
176
177 // Update the amount live at the end of a full GC
178 _live_at_last_full_gc = amount_live;
179
180 // The policy does not have enough data until at least some major collections
181 // have been done.
182 if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) {
183 _old_gen_policy_is_ready = true;
184 }
185
186 // Interval times use this timer to measure the interval that
187 // the mutator runs. Reset after the GC pause has been measured.
188 _major_timer.reset();
189 _major_timer.start();
190 }
191
192 // If the remaining free space in the old generation is less that
193 // that expected to be needed by the next collection, do a full
194 // collection now.
195 bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) {
196
197 // A similar test is done in the scavenge's should_attempt_scavenge(). If
198 // this is changed, decide if that test should also be changed.
199 bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes;
200 if (PrintGCDetails && Verbose) {
201 if (result) {
202 gclog_or_tty->print(" full after scavenge: ");
203 } else {
204 gclog_or_tty->print(" no full after scavenge: ");
205 }
206 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
207 " padded_average_promoted " SIZE_FORMAT
208 " free in old gen " SIZE_FORMAT,
209 (size_t) average_promoted_in_bytes(),
210 (size_t) padded_average_promoted_in_bytes(),
211 old_free_in_bytes);
212 }
213 return result;
214 }
215
216 void PSAdaptiveSizePolicy::clear_generation_free_space_flags() {
217
218 AdaptiveSizePolicy::clear_generation_free_space_flags();
219
220 set_change_old_gen_for_min_pauses(0);
221
222 set_change_young_gen_for_maj_pauses(0);
223 }
224
225 // If this is not a full GC, only test and modify the young generation.
226
227 void PSAdaptiveSizePolicy::compute_generations_free_space(
228 size_t young_live,
229 size_t eden_live,
230 size_t old_live,
231 size_t cur_eden,
232 size_t max_old_gen_size,
233 size_t max_eden_size,
234 bool is_full_gc) {
235 compute_eden_space_size(young_live,
236 eden_live,
237 cur_eden,
238 max_eden_size,
239 is_full_gc);
240
241 compute_old_gen_free_space(old_live,
242 cur_eden,
243 max_old_gen_size,
244 is_full_gc);
245 }
246
247 void PSAdaptiveSizePolicy::compute_eden_space_size(
248 size_t young_live,
249 size_t eden_live,
250 size_t cur_eden,
251 size_t max_eden_size,
252 bool is_full_gc) {
253
254 // Update statistics
255 // Time statistics are updated as we go, update footprint stats here
256 _avg_base_footprint->sample(BaseFootPrintEstimate);
257 avg_young_live()->sample(young_live);
258 avg_eden_live()->sample(eden_live);
259
260 // This code used to return if the policy was not ready , i.e.,
261 // policy_is_ready() returning false. The intent was that
262 // decisions below needed major collection times and so could
263 // not be made before two major collections. A consequence was
264 // adjustments to the young generation were not done until after
265 // two major collections even if the minor collections times
266 // exceeded the requested goals. Now let the young generation
267 // adjust for the minor collection times. Major collection times
268 // will be zero for the first collection and will naturally be
269 // ignored. Tenured generation adjustments are only made at the
270 // full collections so until the second major collection has
271 // been reached, no tenured generation adjustments will be made.
272
273 // Until we know better, desired promotion size uses the last calculation
274 size_t desired_promo_size = _promo_size;
275
276 // Start eden at the current value. The desired value that is stored
277 // in _eden_size is not bounded by constraints of the heap and can
278 // run away.
279 //
280 // As expected setting desired_eden_size to the current
281 // value of desired_eden_size as a starting point
282 // caused desired_eden_size to grow way too large and caused
283 // an overflow down stream. It may have improved performance in
284 // some case but is dangerous.
285 size_t desired_eden_size = cur_eden;
286
287 // Cache some values. There's a bit of work getting these, so
288 // we might save a little time.
289 const double major_cost = major_gc_cost();
290 const double minor_cost = minor_gc_cost();
291
292 // This method sets the desired eden size. That plus the
293 // desired survivor space sizes sets the desired young generation
294 // size. This methods does not know what the desired survivor
295 // size is but expects that other policy will attempt to make
296 // the survivor sizes compatible with the live data in the
297 // young generation. This limit is an estimate of the space left
298 // in the young generation after the survivor spaces have been
299 // subtracted out.
300 size_t eden_limit = max_eden_size;
301
302 const double gc_cost_limit = GCTimeLimit / 100.0;
303
304 // Which way should we go?
305 // if pause requirement is not met
306 // adjust size of any generation with average paus exceeding
307 // the pause limit. Adjust one pause at a time (the larger)
308 // and only make adjustments for the major pause at full collections.
309 // else if throughput requirement not met
310 // adjust the size of the generation with larger gc time. Only
311 // adjust one generation at a time.
312 // else
313 // adjust down the total heap size. Adjust down the larger of the
314 // generations.
315
316 // Add some checks for a threshold for a change. For example,
317 // a change less than the necessary alignment is probably not worth
318 // attempting.
319
320
321 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
322 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
323 //
324 // Check pauses
325 //
326 // Make changes only to affect one of the pauses (the larger)
327 // at a time.
328 adjust_eden_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
329
330 } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
331 // Adjust only for the minor pause time goal
332 adjust_eden_for_minor_pause_time(is_full_gc, &desired_eden_size);
333
334 } else if(adjusted_mutator_cost() < _throughput_goal) {
335 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
336 // This sometimes resulted in skipping to the minimize footprint
337 // code. Change this to try and reduce GC time if mutator time is
338 // negative for whatever reason. Or for future consideration,
339 // bail out of the code if mutator time is negative.
340 //
341 // Throughput
342 //
343 assert(major_cost >= 0.0, "major cost is < 0.0");
344 assert(minor_cost >= 0.0, "minor cost is < 0.0");
345 // Try to reduce the GC times.
346 adjust_eden_for_throughput(is_full_gc, &desired_eden_size);
347
348 } else {
349
350 // Be conservative about reducing the footprint.
351 // Do a minimum number of major collections first.
352 // Have reasonable averages for major and minor collections costs.
353 if (UseAdaptiveSizePolicyFootprintGoal &&
354 young_gen_policy_is_ready() &&
355 avg_major_gc_cost()->average() >= 0.0 &&
356 avg_minor_gc_cost()->average() >= 0.0) {
357 size_t desired_sum = desired_eden_size + desired_promo_size;
358 desired_eden_size = adjust_eden_for_footprint(desired_eden_size, desired_sum);
359 }
360 }
361
362 // Note we make the same tests as in the code block below; the code
363 // seems a little easier to read with the printing in another block.
364 if (PrintAdaptiveSizePolicy) {
365 if (desired_eden_size > eden_limit) {
366 gclog_or_tty->print_cr(
367 "PSAdaptiveSizePolicy::compute_eden_space_size limits:"
368 " desired_eden_size: " SIZE_FORMAT
369 " old_eden_size: " SIZE_FORMAT
370 " eden_limit: " SIZE_FORMAT
371 " cur_eden: " SIZE_FORMAT
372 " max_eden_size: " SIZE_FORMAT
373 " avg_young_live: " SIZE_FORMAT,
374 desired_eden_size, _eden_size, eden_limit, cur_eden,
375 max_eden_size, (size_t)avg_young_live()->average());
376 }
377 if (gc_cost() > gc_cost_limit) {
378 gclog_or_tty->print_cr(
379 "PSAdaptiveSizePolicy::compute_eden_space_size: gc time limit"
380 " gc_cost: %f "
381 " GCTimeLimit: " UINTX_FORMAT,
382 gc_cost(), GCTimeLimit);
383 }
384 }
385
386 // Align everything and make a final limit check
387 desired_eden_size = align_size_up(desired_eden_size, _space_alignment);
388 desired_eden_size = MAX2(desired_eden_size, _space_alignment);
389
390 eden_limit = align_size_down(eden_limit, _space_alignment);
391
392 // And one last limit check, now that we've aligned things.
393 if (desired_eden_size > eden_limit) {
394 // If the policy says to get a larger eden but
395 // is hitting the limit, don't decrease eden.
396 // This can lead to a general drifting down of the
397 // eden size. Let the tenuring calculation push more
398 // into the old gen.
399 desired_eden_size = MAX2(eden_limit, cur_eden);
400 }
401
402 if (PrintAdaptiveSizePolicy) {
403 // Timing stats
404 gclog_or_tty->print(
405 "PSAdaptiveSizePolicy::compute_eden_space_size: costs"
406 " minor_time: %f"
407 " major_cost: %f"
408 " mutator_cost: %f"
409 " throughput_goal: %f",
410 minor_gc_cost(), major_gc_cost(), mutator_cost(),
411 _throughput_goal);
412
413 // We give more details if Verbose is set
414 if (Verbose) {
415 gclog_or_tty->print( " minor_pause: %f"
416 " major_pause: %f"
417 " minor_interval: %f"
418 " major_interval: %f"
419 " pause_goal: %f",
420 _avg_minor_pause->padded_average(),
421 _avg_major_pause->padded_average(),
422 _avg_minor_interval->average(),
423 _avg_major_interval->average(),
424 gc_pause_goal_sec());
425 }
426
427 // Footprint stats
428 gclog_or_tty->print( " live_space: " SIZE_FORMAT
429 " free_space: " SIZE_FORMAT,
430 live_space(), free_space());
431 // More detail
432 if (Verbose) {
433 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
434 " avg_young_live: " SIZE_FORMAT
435 " avg_old_live: " SIZE_FORMAT,
436 (size_t)_avg_base_footprint->average(),
437 (size_t)avg_young_live()->average(),
438 (size_t)avg_old_live()->average());
439 }
440
441 // And finally, our old and new sizes.
442 gclog_or_tty->print(" old_eden_size: " SIZE_FORMAT
443 " desired_eden_size: " SIZE_FORMAT,
444 _eden_size, desired_eden_size);
445 gclog_or_tty->cr();
446 }
447
448 set_eden_size(desired_eden_size);
449 }
450
451 void PSAdaptiveSizePolicy::compute_old_gen_free_space(
452 size_t old_live,
453 size_t cur_eden,
454 size_t max_old_gen_size,
455 bool is_full_gc) {
456
457 // Update statistics
458 // Time statistics are updated as we go, update footprint stats here
459 if (is_full_gc) {
460 // old_live is only accurate after a full gc
461 avg_old_live()->sample(old_live);
462 }
463
464 // This code used to return if the policy was not ready , i.e.,
465 // policy_is_ready() returning false. The intent was that
466 // decisions below needed major collection times and so could
467 // not be made before two major collections. A consequence was
468 // adjustments to the young generation were not done until after
469 // two major collections even if the minor collections times
470 // exceeded the requested goals. Now let the young generation
471 // adjust for the minor collection times. Major collection times
472 // will be zero for the first collection and will naturally be
473 // ignored. Tenured generation adjustments are only made at the
474 // full collections so until the second major collection has
475 // been reached, no tenured generation adjustments will be made.
476
477 // Until we know better, desired promotion size uses the last calculation
478 size_t desired_promo_size = _promo_size;
479
480 // Start eden at the current value. The desired value that is stored
481 // in _eden_size is not bounded by constraints of the heap and can
482 // run away.
483 //
484 // As expected setting desired_eden_size to the current
485 // value of desired_eden_size as a starting point
486 // caused desired_eden_size to grow way too large and caused
487 // an overflow down stream. It may have improved performance in
488 // some case but is dangerous.
489 size_t desired_eden_size = cur_eden;
490
491 // Cache some values. There's a bit of work getting these, so
492 // we might save a little time.
493 const double major_cost = major_gc_cost();
494 const double minor_cost = minor_gc_cost();
495
496 // Limits on our growth
497 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
498
499 // But don't force a promo size below the current promo size. Otherwise,
500 // the promo size will shrink for no good reason.
501 promo_limit = MAX2(promo_limit, _promo_size);
502
503 const double gc_cost_limit = GCTimeLimit/100.0;
504
505 // Which way should we go?
506 // if pause requirement is not met
507 // adjust size of any generation with average paus exceeding
508 // the pause limit. Adjust one pause at a time (the larger)
509 // and only make adjustments for the major pause at full collections.
510 // else if throughput requirement not met
511 // adjust the size of the generation with larger gc time. Only
512 // adjust one generation at a time.
513 // else
514 // adjust down the total heap size. Adjust down the larger of the
515 // generations.
516
517 // Add some checks for a threshold for a change. For example,
518 // a change less than the necessary alignment is probably not worth
519 // attempting.
520
521 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
522 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
523 //
524 // Check pauses
525 //
526 // Make changes only to affect one of the pauses (the larger)
527 // at a time.
528 if (is_full_gc) {
529 set_decide_at_full_gc(decide_at_full_gc_true);
530 adjust_promo_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
531 }
532 } else if (adjusted_mutator_cost() < _throughput_goal) {
533 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
534 // This sometimes resulted in skipping to the minimize footprint
535 // code. Change this to try and reduce GC time if mutator time is
536 // negative for whatever reason. Or for future consideration,
537 // bail out of the code if mutator time is negative.
538 //
539 // Throughput
540 //
541 assert(major_cost >= 0.0, "major cost is < 0.0");
542 assert(minor_cost >= 0.0, "minor cost is < 0.0");
543 // Try to reduce the GC times.
544 if (is_full_gc) {
545 set_decide_at_full_gc(decide_at_full_gc_true);
546 adjust_promo_for_throughput(is_full_gc, &desired_promo_size);
547 }
548 } else {
549
550 // Be conservative about reducing the footprint.
551 // Do a minimum number of major collections first.
552 // Have reasonable averages for major and minor collections costs.
553 if (UseAdaptiveSizePolicyFootprintGoal &&
554 young_gen_policy_is_ready() &&
555 avg_major_gc_cost()->average() >= 0.0 &&
556 avg_minor_gc_cost()->average() >= 0.0) {
557 if (is_full_gc) {
558 set_decide_at_full_gc(decide_at_full_gc_true);
559 size_t desired_sum = desired_eden_size + desired_promo_size;
560 desired_promo_size = adjust_promo_for_footprint(desired_promo_size, desired_sum);
561 }
562 }
563 }
564
565 // Note we make the same tests as in the code block below; the code
566 // seems a little easier to read with the printing in another block.
567 if (PrintAdaptiveSizePolicy) {
568 if (desired_promo_size > promo_limit) {
569 // "free_in_old_gen" was the original value for used for promo_limit
570 size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
571 gclog_or_tty->print_cr(
572 "PSAdaptiveSizePolicy::compute_old_gen_free_space limits:"
573 " desired_promo_size: " SIZE_FORMAT
574 " promo_limit: " SIZE_FORMAT
575 " free_in_old_gen: " SIZE_FORMAT
576 " max_old_gen_size: " SIZE_FORMAT
577 " avg_old_live: " SIZE_FORMAT,
578 desired_promo_size, promo_limit, free_in_old_gen,
579 max_old_gen_size, (size_t) avg_old_live()->average());
580 }
581 if (gc_cost() > gc_cost_limit) {
582 gclog_or_tty->print_cr(
583 "PSAdaptiveSizePolicy::compute_old_gen_free_space: gc time limit"
584 " gc_cost: %f "
585 " GCTimeLimit: " UINTX_FORMAT,
586 gc_cost(), GCTimeLimit);
587 }
588 }
589
590 // Align everything and make a final limit check
591 desired_promo_size = align_size_up(desired_promo_size, _space_alignment);
592 desired_promo_size = MAX2(desired_promo_size, _space_alignment);
593
594 promo_limit = align_size_down(promo_limit, _space_alignment);
595
596 // And one last limit check, now that we've aligned things.
597 desired_promo_size = MIN2(desired_promo_size, promo_limit);
598
599 if (PrintAdaptiveSizePolicy) {
600 // Timing stats
601 gclog_or_tty->print(
602 "PSAdaptiveSizePolicy::compute_old_gen_free_space: costs"
603 " minor_time: %f"
604 " major_cost: %f"
605 " mutator_cost: %f"
606 " throughput_goal: %f",
607 minor_gc_cost(), major_gc_cost(), mutator_cost(),
608 _throughput_goal);
609
610 // We give more details if Verbose is set
611 if (Verbose) {
612 gclog_or_tty->print( " minor_pause: %f"
613 " major_pause: %f"
614 " minor_interval: %f"
615 " major_interval: %f"
616 " pause_goal: %f",
617 _avg_minor_pause->padded_average(),
618 _avg_major_pause->padded_average(),
619 _avg_minor_interval->average(),
620 _avg_major_interval->average(),
621 gc_pause_goal_sec());
622 }
623
624 // Footprint stats
625 gclog_or_tty->print( " live_space: " SIZE_FORMAT
626 " free_space: " SIZE_FORMAT,
627 live_space(), free_space());
628 // More detail
629 if (Verbose) {
630 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
631 " avg_young_live: " SIZE_FORMAT
632 " avg_old_live: " SIZE_FORMAT,
633 (size_t)_avg_base_footprint->average(),
634 (size_t)avg_young_live()->average(),
635 (size_t)avg_old_live()->average());
636 }
637
638 // And finally, our old and new sizes.
639 gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT
640 " desired_promo_size: " SIZE_FORMAT,
641 _promo_size, desired_promo_size);
642 gclog_or_tty->cr();
643 }
644
645 set_promo_size(desired_promo_size);
646 }
647
648 void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) {
649 // Decay the supplemental increment? Decay the supplement growth
650 // factor even if it is not used. It is only meant to give a boost
651 // to the initial growth and if it is not used, then it was not
652 // needed.
653 if (is_full_gc) {
654 // Don't wait for the threshold value for the major collections. If
655 // here, the supplemental growth term was used and should decay.
656 if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay)
657 == 0) {
658 _old_gen_size_increment_supplement =
659 _old_gen_size_increment_supplement >> 1;
660 }
661 } else {
662 if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) &&
663 (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) {
664 _young_gen_size_increment_supplement =
665 _young_gen_size_increment_supplement >> 1;
666 }
667 }
668 }
669
670 void PSAdaptiveSizePolicy::adjust_eden_for_minor_pause_time(bool is_full_gc,
671 size_t* desired_eden_size_ptr) {
672
673 // Adjust the young generation size to reduce pause time of
674 // of collections.
675 //
676 // The AdaptiveSizePolicyInitializingSteps test is not used
677 // here. It has not seemed to be needed but perhaps should
678 // be added for consistency.
679 if (minor_pause_young_estimator()->decrement_will_decrease()) {
680 // reduce eden size
681 set_change_young_gen_for_min_pauses(
682 decrease_young_gen_for_min_pauses_true);
683 *desired_eden_size_ptr = *desired_eden_size_ptr -
684 eden_decrement_aligned_down(*desired_eden_size_ptr);
685 } else {
686 // EXPERIMENTAL ADJUSTMENT
687 // Only record that the estimator indicated such an action.
688 // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta;
689 set_change_young_gen_for_min_pauses(
690 increase_young_gen_for_min_pauses_true);
691 }
692 }
693
694 void PSAdaptiveSizePolicy::adjust_promo_for_pause_time(bool is_full_gc,
695 size_t* desired_promo_size_ptr,
696 size_t* desired_eden_size_ptr) {
697
698 size_t promo_heap_delta = 0;
699 // Add some checks for a threshold for a change. For example,
700 // a change less than the required alignment is probably not worth
701 // attempting.
702
703 if (_avg_minor_pause->padded_average() <= _avg_major_pause->padded_average() && is_full_gc) {
704 // Adjust for the major pause time only at full gc's because the
705 // affects of a change can only be seen at full gc's.
706
707 // Reduce old generation size to reduce pause?
708 if (major_pause_old_estimator()->decrement_will_decrease()) {
709 // reduce old generation size
710 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
711 promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr);
712 *desired_promo_size_ptr = _promo_size - promo_heap_delta;
713 } else {
714 // EXPERIMENTAL ADJUSTMENT
715 // Only record that the estimator indicated such an action.
716 // *desired_promo_size_ptr = _promo_size +
717 // promo_increment_aligned_up(*desired_promo_size_ptr);
718 set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true);
719 }
720 }
721
722 if (PrintAdaptiveSizePolicy && Verbose) {
723 gclog_or_tty->print_cr(
724 "PSAdaptiveSizePolicy::adjust_promo_for_pause_time "
725 "adjusting gen sizes for major pause (avg %f goal %f). "
726 "desired_promo_size " SIZE_FORMAT " promo delta " SIZE_FORMAT,
727 _avg_major_pause->average(), gc_pause_goal_sec(),
728 *desired_promo_size_ptr, promo_heap_delta);
729 }
730 }
731
732 void PSAdaptiveSizePolicy::adjust_eden_for_pause_time(bool is_full_gc,
733 size_t* desired_promo_size_ptr,
734 size_t* desired_eden_size_ptr) {
735
736 size_t eden_heap_delta = 0;
737 // Add some checks for a threshold for a change. For example,
738 // a change less than the required alignment is probably not worth
739 // attempting.
740 if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
741 adjust_eden_for_minor_pause_time(is_full_gc, desired_eden_size_ptr);
742 }
743 if (PrintAdaptiveSizePolicy && Verbose) {
744 gclog_or_tty->print_cr(
745 "PSAdaptiveSizePolicy::adjust_eden_for_pause_time "
746 "adjusting gen sizes for major pause (avg %f goal %f). "
747 "desired_eden_size " SIZE_FORMAT " eden delta " SIZE_FORMAT,
748 _avg_major_pause->average(), gc_pause_goal_sec(),
749 *desired_eden_size_ptr, eden_heap_delta);
750 }
751 }
752
753 void PSAdaptiveSizePolicy::adjust_promo_for_throughput(bool is_full_gc,
754 size_t* desired_promo_size_ptr) {
755
756 // Add some checks for a threshold for a change. For example,
757 // a change less than the required alignment is probably not worth
758 // attempting.
759
760 if ((gc_cost() + mutator_cost()) == 0.0) {
761 return;
762 }
763
764 if (PrintAdaptiveSizePolicy && Verbose) {
765 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_promo_for_throughput("
766 "is_full: %d, promo: " SIZE_FORMAT "): ",
767 is_full_gc, *desired_promo_size_ptr);
768 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
769 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
770 }
771
772 // Tenured generation
773 if (is_full_gc) {
774 // Calculate the change to use for the tenured gen.
775 size_t scaled_promo_heap_delta = 0;
776 // Can the increment to the generation be scaled?
777 if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) {
778 size_t promo_heap_delta =
779 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
780 double scale_by_ratio = major_gc_cost() / gc_cost();
781 scaled_promo_heap_delta =
782 (size_t) (scale_by_ratio * (double) promo_heap_delta);
783 if (PrintAdaptiveSizePolicy && Verbose) {
784 gclog_or_tty->print_cr(
785 "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
786 SIZE_FORMAT,
787 promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta);
788 }
789 } else if (major_gc_cost() >= 0.0) {
790 // Scaling is not going to work. If the major gc time is the
791 // larger, give it a full increment.
792 if (major_gc_cost() >= minor_gc_cost()) {
793 scaled_promo_heap_delta =
794 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
795 }
796 } else {
797 // Don't expect to get here but it's ok if it does
798 // in the product build since the delta will be 0
799 // and nothing will change.
800 assert(false, "Unexpected value for gc costs");
801 }
802
803 switch (AdaptiveSizeThroughPutPolicy) {
804 case 1:
805 // Early in the run the statistics might not be good. Until
806 // a specific number of collections have been, use the heuristic
807 // that a larger generation size means lower collection costs.
808 if (major_collection_estimator()->increment_will_decrease() ||
809 (_old_gen_change_for_major_throughput
810 <= AdaptiveSizePolicyInitializingSteps)) {
811 // Increase tenured generation size to reduce major collection cost
812 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
813 *desired_promo_size_ptr) {
814 *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta;
815 }
816 set_change_old_gen_for_throughput(
817 increase_old_gen_for_throughput_true);
818 _old_gen_change_for_major_throughput++;
819 } else {
820 // EXPERIMENTAL ADJUSTMENT
821 // Record that decreasing the old gen size would decrease
822 // the major collection cost but don't do it.
823 // *desired_promo_size_ptr = _promo_size -
824 // promo_decrement_aligned_down(*desired_promo_size_ptr);
825 set_change_old_gen_for_throughput(
826 decrease_old_gen_for_throughput_true);
827 }
828
829 break;
830 default:
831 // Simplest strategy
832 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
833 *desired_promo_size_ptr) {
834 *desired_promo_size_ptr = *desired_promo_size_ptr +
835 scaled_promo_heap_delta;
836 }
837 set_change_old_gen_for_throughput(
838 increase_old_gen_for_throughput_true);
839 _old_gen_change_for_major_throughput++;
840 }
841
842 if (PrintAdaptiveSizePolicy && Verbose) {
843 gclog_or_tty->print_cr(
844 "adjusting tenured gen for throughput (avg %f goal %f). "
845 "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT ,
846 mutator_cost(), _throughput_goal,
847 *desired_promo_size_ptr, scaled_promo_heap_delta);
848 }
849 }
850 }
851
852 void PSAdaptiveSizePolicy::adjust_eden_for_throughput(bool is_full_gc,
853 size_t* desired_eden_size_ptr) {
854
855 // Add some checks for a threshold for a change. For example,
856 // a change less than the required alignment is probably not worth
857 // attempting.
858
859 if ((gc_cost() + mutator_cost()) == 0.0) {
860 return;
861 }
862
863 if (PrintAdaptiveSizePolicy && Verbose) {
864 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_eden_for_throughput("
865 "is_full: %d, cur_eden: " SIZE_FORMAT "): ",
866 is_full_gc, *desired_eden_size_ptr);
867 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
868 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
869 }
870
871 // Young generation
872 size_t scaled_eden_heap_delta = 0;
873 // Can the increment to the generation be scaled?
874 if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) {
875 size_t eden_heap_delta =
876 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
877 double scale_by_ratio = minor_gc_cost() / gc_cost();
878 assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong");
879 scaled_eden_heap_delta =
880 (size_t) (scale_by_ratio * (double) eden_heap_delta);
881 if (PrintAdaptiveSizePolicy && Verbose) {
882 gclog_or_tty->print_cr(
883 "Scaled eden increment: " SIZE_FORMAT " by %f down to "
884 SIZE_FORMAT,
885 eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta);
886 }
887 } else if (minor_gc_cost() >= 0.0) {
888 // Scaling is not going to work. If the minor gc time is the
889 // larger, give it a full increment.
890 if (minor_gc_cost() > major_gc_cost()) {
891 scaled_eden_heap_delta =
892 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
893 }
894 } else {
895 // Don't expect to get here but it's ok if it does
896 // in the product build since the delta will be 0
897 // and nothing will change.
898 assert(false, "Unexpected value for gc costs");
899 }
900
901 // Use a heuristic for some number of collections to give
902 // the averages time to settle down.
903 switch (AdaptiveSizeThroughPutPolicy) {
904 case 1:
905 if (minor_collection_estimator()->increment_will_decrease() ||
906 (_young_gen_change_for_minor_throughput
907 <= AdaptiveSizePolicyInitializingSteps)) {
908 // Expand young generation size to reduce frequency of
909 // of collections.
910 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
911 *desired_eden_size_ptr) {
912 *desired_eden_size_ptr =
913 *desired_eden_size_ptr + scaled_eden_heap_delta;
914 }
915 set_change_young_gen_for_throughput(
916 increase_young_gen_for_througput_true);
917 _young_gen_change_for_minor_throughput++;
918 } else {
919 // EXPERIMENTAL ADJUSTMENT
920 // Record that decreasing the young gen size would decrease
921 // the minor collection cost but don't do it.
922 // *desired_eden_size_ptr = _eden_size -
923 // eden_decrement_aligned_down(*desired_eden_size_ptr);
924 set_change_young_gen_for_throughput(
925 decrease_young_gen_for_througput_true);
926 }
927 break;
928 default:
929 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
930 *desired_eden_size_ptr) {
931 *desired_eden_size_ptr =
932 *desired_eden_size_ptr + scaled_eden_heap_delta;
933 }
934 set_change_young_gen_for_throughput(
935 increase_young_gen_for_througput_true);
936 _young_gen_change_for_minor_throughput++;
937 }
938
939 if (PrintAdaptiveSizePolicy && Verbose) {
940 gclog_or_tty->print_cr(
941 "adjusting eden for throughput (avg %f goal %f). desired_eden_size "
942 SIZE_FORMAT " eden delta " SIZE_FORMAT "\n",
943 mutator_cost(), _throughput_goal,
944 *desired_eden_size_ptr, scaled_eden_heap_delta);
945 }
946 }
947
948 size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint(
949 size_t desired_promo_size, size_t desired_sum) {
950 assert(desired_promo_size <= desired_sum, "Inconsistent parameters");
951 set_decrease_for_footprint(decrease_old_gen_for_footprint_true);
952
953 size_t change = promo_decrement(desired_promo_size);
954 change = scale_down(change, desired_promo_size, desired_sum);
955
956 size_t reduced_size = desired_promo_size - change;
957
958 if (PrintAdaptiveSizePolicy && Verbose) {
959 gclog_or_tty->print_cr(
960 "AdaptiveSizePolicy::adjust_promo_for_footprint "
961 "adjusting tenured gen for footprint. "
962 "starting promo size " SIZE_FORMAT
963 " reduced promo size " SIZE_FORMAT
964 " promo delta " SIZE_FORMAT,
965 desired_promo_size, reduced_size, change );
966 }
967
968 assert(reduced_size <= desired_promo_size, "Inconsistent result");
969 return reduced_size;
970 }
971
972 size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint(
973 size_t desired_eden_size, size_t desired_sum) {
974 assert(desired_eden_size <= desired_sum, "Inconsistent parameters");
975 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
976
977 size_t change = eden_decrement(desired_eden_size);
978 change = scale_down(change, desired_eden_size, desired_sum);
979
980 size_t reduced_size = desired_eden_size - change;
981
982 if (PrintAdaptiveSizePolicy && Verbose) {
983 gclog_or_tty->print_cr(
984 "AdaptiveSizePolicy::adjust_eden_for_footprint "
985 "adjusting eden for footprint. "
986 " starting eden size " SIZE_FORMAT
987 " reduced eden size " SIZE_FORMAT
988 " eden delta " SIZE_FORMAT,
989 desired_eden_size, reduced_size, change);
990 }
991
992 assert(reduced_size <= desired_eden_size, "Inconsistent result");
993 return reduced_size;
994 }
995
996 // Scale down "change" by the factor
997 // part / total
998 // Don't align the results.
999
1000 size_t PSAdaptiveSizePolicy::scale_down(size_t change,
1001 double part,
1002 double total) {
1003 assert(part <= total, "Inconsistent input");
1004 size_t reduced_change = change;
1005 if (total > 0) {
1006 double fraction = part / total;
1007 reduced_change = (size_t) (fraction * (double) change);
1008 }
1009 assert(reduced_change <= change, "Inconsistent result");
1010 return reduced_change;
1011 }
1012
1013 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden,
1014 uint percent_change) {
1015 size_t eden_heap_delta;
1016 eden_heap_delta = cur_eden / 100 * percent_change;
1017 return eden_heap_delta;
1018 }
1019
1020 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) {
1021 return eden_increment(cur_eden, YoungGenerationSizeIncrement);
1022 }
1023
1024 size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
1025 size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement);
1026 return align_size_up(result, _space_alignment);
1027 }
1028
1029 size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) {
1030 size_t result = eden_increment(cur_eden);
1031 return align_size_down(result, _space_alignment);
1032 }
1033
1034 size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up(
1035 size_t cur_eden) {
1036 size_t result = eden_increment(cur_eden,
1037 YoungGenerationSizeIncrement + _young_gen_size_increment_supplement);
1038 return align_size_up(result, _space_alignment);
1039 }
1040
1041 size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
1042 size_t eden_heap_delta = eden_decrement(cur_eden);
1043 return align_size_down(eden_heap_delta, _space_alignment);
1044 }
1045
1046 size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
1047 size_t eden_heap_delta = eden_increment(cur_eden) /
1048 AdaptiveSizeDecrementScaleFactor;
1049 return eden_heap_delta;
1050 }
1051
1052 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo,
1053 uint percent_change) {
1054 size_t promo_heap_delta;
1055 promo_heap_delta = cur_promo / 100 * percent_change;
1056 return promo_heap_delta;
1057 }
1058
1059 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) {
1060 return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
1061 }
1062
1063 size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
1064 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
1065 return align_size_up(result, _space_alignment);
1066 }
1067
1068 size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) {
1069 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
1070 return align_size_down(result, _space_alignment);
1071 }
1072
1073 size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up(
1074 size_t cur_promo) {
1075 size_t result = promo_increment(cur_promo,
1076 TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement);
1077 return align_size_up(result, _space_alignment);
1078 }
1079
1080 size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
1081 size_t promo_heap_delta = promo_decrement(cur_promo);
1082 return align_size_down(promo_heap_delta, _space_alignment);
1083 }
1084
1085 size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
1086 size_t promo_heap_delta = promo_increment(cur_promo);
1087 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
1088 return promo_heap_delta;
1089 }
1090
1091 uint PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
1092 bool is_survivor_overflow,
1093 uint tenuring_threshold,
1094 size_t survivor_limit) {
1095 assert(survivor_limit >= _space_alignment,
1096 "survivor_limit too small");
1097 assert((size_t)align_size_down(survivor_limit, _space_alignment)
1098 == survivor_limit, "survivor_limit not aligned");
1099
1100 // This method is called even if the tenuring threshold and survivor
1101 // spaces are not adjusted so that the averages are sampled above.
1102 if (!UsePSAdaptiveSurvivorSizePolicy ||
1103 !young_gen_policy_is_ready()) {
1104 return tenuring_threshold;
1105 }
1106
1107 // We'll decide whether to increase or decrease the tenuring
1108 // threshold based partly on the newly computed survivor size
1109 // (if we hit the maximum limit allowed, we'll always choose to
1110 // decrement the threshold).
1111 bool incr_tenuring_threshold = false;
1112 bool decr_tenuring_threshold = false;
1113
1114 set_decrement_tenuring_threshold_for_gc_cost(false);
1115 set_increment_tenuring_threshold_for_gc_cost(false);
1116 set_decrement_tenuring_threshold_for_survivor_limit(false);
1117
1118 if (!is_survivor_overflow) {
1119 // Keep running averages on how much survived
1120
1121 // We use the tenuring threshold to equalize the cost of major
1122 // and minor collections.
1123 // ThresholdTolerance is used to indicate how sensitive the
1124 // tenuring threshold is to differences in cost between the
1125 // collection types.
1126
1127 // Get the times of interest. This involves a little work, so
1128 // we cache the values here.
1129 const double major_cost = major_gc_cost();
1130 const double minor_cost = minor_gc_cost();
1131
1132 if (minor_cost > major_cost * _threshold_tolerance_percent) {
1133 // Minor times are getting too long; lower the threshold so
1134 // less survives and more is promoted.
1135 decr_tenuring_threshold = true;
1136 set_decrement_tenuring_threshold_for_gc_cost(true);
1137 } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
1138 // Major times are too long, so we want less promotion.
1139 incr_tenuring_threshold = true;
1140 set_increment_tenuring_threshold_for_gc_cost(true);
1141 }
1142
1143 } else {
1144 // Survivor space overflow occurred, so promoted and survived are
1145 // not accurate. We'll make our best guess by combining survived
1146 // and promoted and count them as survivors.
1147 //
1148 // We'll lower the tenuring threshold to see if we can correct
1149 // things. Also, set the survivor size conservatively. We're
1150 // trying to avoid many overflows from occurring if defnew size
1151 // is just too small.
1152
1153 decr_tenuring_threshold = true;
1154 }
1155
1156 // The padded average also maintains a deviation from the average;
1157 // we use this to see how good of an estimate we have of what survived.
1158 // We're trying to pad the survivor size as little as possible without
1159 // overflowing the survivor spaces.
1160 size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
1161 _space_alignment);
1162 target_size = MAX2(target_size, _space_alignment);
1163
1164 if (target_size > survivor_limit) {
1165 // Target size is bigger than we can handle. Let's also reduce
1166 // the tenuring threshold.
1167 target_size = survivor_limit;
1168 decr_tenuring_threshold = true;
1169 set_decrement_tenuring_threshold_for_survivor_limit(true);
1170 }
1171
1172 // Finally, increment or decrement the tenuring threshold, as decided above.
1173 // We test for decrementing first, as we might have hit the target size
1174 // limit.
1175 if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1176 if (tenuring_threshold > 1) {
1177 tenuring_threshold--;
1178 }
1179 } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1180 if (tenuring_threshold < MaxTenuringThreshold) {
1181 tenuring_threshold++;
1182 }
1183 }
1184
1185 // We keep a running average of the amount promoted which is used
1186 // to decide when we should collect the old generation (when
1187 // the amount of old gen free space is less than what we expect to
1188 // promote).
1189
1190 if (PrintAdaptiveSizePolicy) {
1191 // A little more detail if Verbose is on
1192 if (Verbose) {
1193 gclog_or_tty->print( " avg_survived: %f"
1194 " avg_deviation: %f",
1195 _avg_survived->average(),
1196 _avg_survived->deviation());
1197 }
1198
1199 gclog_or_tty->print( " avg_survived_padded_avg: %f",
1200 _avg_survived->padded_average());
1201
1202 if (Verbose) {
1203 gclog_or_tty->print( " avg_promoted_avg: %f"
1204 " avg_promoted_dev: %f",
1205 avg_promoted()->average(),
1206 avg_promoted()->deviation());
1207 }
1208
1209 gclog_or_tty->print_cr( " avg_promoted_padded_avg: %f"
1210 " avg_pretenured_padded_avg: %f"
1211 " tenuring_thresh: %d"
1212 " target_size: " SIZE_FORMAT,
1213 avg_promoted()->padded_average(),
1214 _avg_pretenured->padded_average(),
1215 tenuring_threshold, target_size);
1216 }
1217
1218 set_survivor_size(target_size);
1219
1220 return tenuring_threshold;
1221 }
1222
1223 void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow,
1224 size_t survived,
1225 size_t promoted) {
1226 // Update averages
1227 if (!is_survivor_overflow) {
1228 // Keep running averages on how much survived
1229 _avg_survived->sample(survived);
1230 } else {
1231 size_t survived_guess = survived + promoted;
1232 _avg_survived->sample(survived_guess);
1233 }
1234 avg_promoted()->sample(promoted);
1235
1236 if (PrintAdaptiveSizePolicy) {
1237 gclog_or_tty->print_cr(
1238 "AdaptiveSizePolicy::update_averages:"
1239 " survived: " SIZE_FORMAT
1240 " promoted: " SIZE_FORMAT
1241 " overflow: %s",
1242 survived, promoted, is_survivor_overflow ? "true" : "false");
1243 }
1244 }
1245
1246 bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st)
1247 const {
1248
1249 if (!UseAdaptiveSizePolicy) return false;
1250
1251 return AdaptiveSizePolicy::print_adaptive_size_policy_on(
1252 st,
1253 PSScavenge::tenuring_threshold());
1254 }
1255
1256 #ifndef PRODUCT
1257
1258 void TestOldFreeSpaceCalculation_test() {
1259 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 20) == 25, "Calculation of free memory failed");
1260 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 50) == 100, "Calculation of free memory failed");
1261 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 60) == 150, "Calculation of free memory failed");
1262 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 75) == 300, "Calculation of free memory failed");
1263 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 20) == 100, "Calculation of free memory failed");
1264 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 50) == 400, "Calculation of free memory failed");
1265 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 60) == 600, "Calculation of free memory failed");
1266 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 75) == 1200, "Calculation of free memory failed");
1267 }
1268
1269 #endif /* !PRODUCT */