1 /*
2 * Copyright (c) 2002, 2010, 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/parallelScavenge/generationSizer.hpp"
27 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
28 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
29 #include "gc_implementation/parallelScavenge/psGCAdaptivePolicyCounters.hpp"
30 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
31 #include "gc_implementation/shared/gcPolicyCounters.hpp"
32 #include "gc_interface/gcCause.hpp"
33 #include "memory/collectorPolicy.hpp"
34 #include "runtime/timer.hpp"
35 #include "utilities/top.hpp"
36
37 #include <math.h>
38
39 PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size,
40 size_t init_promo_size,
41 size_t init_survivor_size,
42 size_t intra_generation_alignment,
43 double gc_pause_goal_sec,
44 double gc_minor_pause_goal_sec,
45 uint gc_cost_ratio) :
46 AdaptiveSizePolicy(init_eden_size,
47 init_promo_size,
48 init_survivor_size,
49 gc_pause_goal_sec,
50 gc_cost_ratio),
51 _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin/
52 100.0),
53 _intra_generation_alignment(intra_generation_alignment),
54 _live_at_last_full_gc(init_promo_size),
55 _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec),
56 _latest_major_mutator_interval_seconds(0),
57 _young_gen_change_for_major_pause_count(0)
58 {
59 // Sizing policy statistics
60 _avg_major_pause =
61 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
62 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
63 _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
64
65 _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
66 _major_pause_old_estimator =
67 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
68 _major_pause_young_estimator =
69 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
70 _major_collection_estimator =
71 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
72
73 _young_gen_size_increment_supplement = YoungGenerationSizeSupplement;
74 _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement;
75
76 // Start the timers
77 _major_timer.start();
78
79 _old_gen_policy_is_ready = false;
80 }
81
82 size_t PSAdaptiveSizePolicy::calculate_free_based_on_live(size_t live, uintx ratio_as_percentage) {
83 // We want to calculate how much free memory there can be based on the
84 // amount of live data currently in the old gen. Using the formula:
85 // ratio * (free + live) = free
86 // Some equation solving later we get:
87 // free = (live * ratio) / (1 - ratio)
88
89 const double ratio = ratio_as_percentage / 100.0;
90 const double ratio_inverse = 1.0 - ratio;
91 const double tmp = live * ratio;
92 size_t free = (size_t)(tmp / ratio_inverse);
93
94 return free;
95 }
96
97 size_t PSAdaptiveSizePolicy::calculated_old_free_size_in_bytes() const {
98 size_t free_size = (size_t)(_promo_size + avg_promoted()->padded_average());
99 size_t live = ParallelScavengeHeap::heap()->old_gen()->used_in_bytes();
100
101 if (MinHeapFreeRatio != 0) {
102 size_t min_free = calculate_free_based_on_live(live, MinHeapFreeRatio);
103 free_size = MAX2(free_size, min_free);
104 }
105
106 if (MaxHeapFreeRatio != 100) {
107 size_t max_free = calculate_free_based_on_live(live, MaxHeapFreeRatio);
108 free_size = MIN2(max_free, free_size);
109 }
110
111 return free_size;
112 }
113
114 void PSAdaptiveSizePolicy::major_collection_begin() {
115 // Update the interval time
116 _major_timer.stop();
117 // Save most recent collection time
118 _latest_major_mutator_interval_seconds = _major_timer.seconds();
119 _major_timer.reset();
120 _major_timer.start();
121 }
122
123 void PSAdaptiveSizePolicy::update_minor_pause_old_estimator(
124 double minor_pause_in_ms) {
125 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
126 _minor_pause_old_estimator->update(promo_size_in_mbytes,
127 minor_pause_in_ms);
128 }
129
130 void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live,
131 GCCause::Cause gc_cause) {
132 // Update the pause time.
133 _major_timer.stop();
134
135 if (gc_cause != GCCause::_java_lang_system_gc ||
136 UseAdaptiveSizePolicyWithSystemGC) {
137 double major_pause_in_seconds = _major_timer.seconds();
138 double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS;
139
140 // Sample for performance counter
141 _avg_major_pause->sample(major_pause_in_seconds);
142
143 // Cost of collection (unit-less)
144 double collection_cost = 0.0;
145 if ((_latest_major_mutator_interval_seconds > 0.0) &&
146 (major_pause_in_seconds > 0.0)) {
147 double interval_in_seconds =
148 _latest_major_mutator_interval_seconds + major_pause_in_seconds;
149 collection_cost =
150 major_pause_in_seconds / interval_in_seconds;
151 avg_major_gc_cost()->sample(collection_cost);
152
153 // Sample for performance counter
154 _avg_major_interval->sample(interval_in_seconds);
155 }
156
157 // Calculate variables used to estimate pause time vs. gen sizes
158 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
159 double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
160 _major_pause_old_estimator->update(promo_size_in_mbytes,
161 major_pause_in_ms);
162 _major_pause_young_estimator->update(eden_size_in_mbytes,
163 major_pause_in_ms);
164
165 if (PrintAdaptiveSizePolicy && Verbose) {
166 gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: "
167 "major gc cost: %f average: %f", collection_cost,
168 avg_major_gc_cost()->average());
169 gclog_or_tty->print_cr(" major pause: %f major period %f",
170 major_pause_in_ms,
171 _latest_major_mutator_interval_seconds * MILLIUNITS);
172 }
173
174 // Calculate variable used to estimate collection cost vs. gen sizes
175 assert(collection_cost >= 0.0, "Expected to be non-negative");
176 _major_collection_estimator->update(promo_size_in_mbytes,
177 collection_cost);
178 }
179
180 // Update the amount live at the end of a full GC
181 _live_at_last_full_gc = amount_live;
182
183 // The policy does not have enough data until at least some major collections
184 // have been done.
185 if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) {
186 _old_gen_policy_is_ready = true;
187 }
188
189 // Interval times use this timer to measure the interval that
190 // the mutator runs. Reset after the GC pause has been measured.
191 _major_timer.reset();
192 _major_timer.start();
193 }
194
195 // If the remaining free space in the old generation is less that
196 // that expected to be needed by the next collection, do a full
197 // collection now.
198 bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) {
199
200 // A similar test is done in the scavenge's should_attempt_scavenge(). If
201 // this is changed, decide if that test should also be changed.
202 bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes;
203 if (PrintGCDetails && Verbose) {
204 if (result) {
205 gclog_or_tty->print(" full after scavenge: ");
206 } else {
207 gclog_or_tty->print(" no full after scavenge: ");
208 }
209 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
210 " padded_average_promoted " SIZE_FORMAT
211 " free in old gen " SIZE_FORMAT,
212 (size_t) average_promoted_in_bytes(),
213 (size_t) padded_average_promoted_in_bytes(),
214 old_free_in_bytes);
215 }
216 return result;
217 }
218
219 void PSAdaptiveSizePolicy::clear_generation_free_space_flags() {
220
221 AdaptiveSizePolicy::clear_generation_free_space_flags();
222
223 set_change_old_gen_for_min_pauses(0);
224
225 set_change_young_gen_for_maj_pauses(0);
226 }
227
228 // If this is not a full GC, only test and modify the young generation.
229
230 void PSAdaptiveSizePolicy::compute_generation_free_space(
231 size_t young_live,
232 size_t eden_live,
233 size_t old_live,
234 size_t perm_live,
235 size_t cur_eden,
236 size_t max_old_gen_size,
237 size_t max_eden_size,
238 bool is_full_gc,
239 GCCause::Cause gc_cause,
240 CollectorPolicy* collector_policy) {
241
242 // Update statistics
243 // Time statistics are updated as we go, update footprint stats here
244 _avg_base_footprint->sample(BaseFootPrintEstimate + perm_live);
245 avg_young_live()->sample(young_live);
246 avg_eden_live()->sample(eden_live);
247 if (is_full_gc) {
248 // old_live is only accurate after a full gc
249 avg_old_live()->sample(old_live);
250 }
251
252 // This code used to return if the policy was not ready , i.e.,
253 // policy_is_ready() returning false. The intent was that
254 // decisions below needed major collection times and so could
255 // not be made before two major collections. A consequence was
256 // adjustments to the young generation were not done until after
257 // two major collections even if the minor collections times
258 // exceeded the requested goals. Now let the young generation
259 // adjust for the minor collection times. Major collection times
260 // will be zero for the first collection and will naturally be
261 // ignored. Tenured generation adjustments are only made at the
262 // full collections so until the second major collection has
263 // been reached, no tenured generation adjustments will be made.
264
265 // Until we know better, desired promotion size uses the last calculation
266 size_t desired_promo_size = _promo_size;
267
268 // Start eden at the current value. The desired value that is stored
269 // in _eden_size is not bounded by constraints of the heap and can
270 // run away.
271 //
272 // As expected setting desired_eden_size to the current
273 // value of desired_eden_size as a starting point
274 // caused desired_eden_size to grow way too large and caused
275 // an overflow down stream. It may have improved performance in
276 // some case but is dangerous.
277 size_t desired_eden_size = cur_eden;
278
279 #ifdef ASSERT
280 size_t original_promo_size = desired_promo_size;
281 size_t original_eden_size = desired_eden_size;
282 #endif
283
284 // Cache some values. There's a bit of work getting these, so
285 // we might save a little time.
286 const double major_cost = major_gc_cost();
287 const double minor_cost = minor_gc_cost();
288
289 // Used for diagnostics
290 clear_generation_free_space_flags();
291
292 // Limits on our growth
293 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
294
295 // This method sets the desired eden size. That plus the
296 // desired survivor space sizes sets the desired young generation
297 // size. This methods does not know what the desired survivor
298 // size is but expects that other policy will attempt to make
299 // the survivor sizes compatible with the live data in the
300 // young generation. This limit is an estimate of the space left
301 // in the young generation after the survivor spaces have been
302 // subtracted out.
303 size_t eden_limit = max_eden_size;
304
305 // But don't force a promo size below the current promo size. Otherwise,
306 // the promo size will shrink for no good reason.
307 promo_limit = MAX2(promo_limit, _promo_size);
308
309 const double gc_cost_limit = GCTimeLimit/100.0;
310
311 // Which way should we go?
312 // if pause requirement is not met
313 // adjust size of any generation with average paus exceeding
314 // the pause limit. Adjust one pause at a time (the larger)
315 // and only make adjustments for the major pause at full collections.
316 // else if throughput requirement not met
317 // adjust the size of the generation with larger gc time. Only
318 // adjust one generation at a time.
319 // else
320 // adjust down the total heap size. Adjust down the larger of the
321 // generations.
322
323 // Add some checks for a threshhold for a change. For example,
324 // a change less than the necessary alignment is probably not worth
325 // attempting.
326
327
328 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
329 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
330 //
331 // Check pauses
332 //
333 // Make changes only to affect one of the pauses (the larger)
334 // at a time.
335 adjust_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
336
337 } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
338 // Adjust only for the minor pause time goal
339 adjust_for_minor_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
340
341 } else if(adjusted_mutator_cost() < _throughput_goal) {
342 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
343 // This sometimes resulted in skipping to the minimize footprint
344 // code. Change this to try and reduce GC time if mutator time is
345 // negative for whatever reason. Or for future consideration,
346 // bail out of the code if mutator time is negative.
347 //
348 // Throughput
349 //
350 assert(major_cost >= 0.0, "major cost is < 0.0");
351 assert(minor_cost >= 0.0, "minor cost is < 0.0");
352 // Try to reduce the GC times.
353 adjust_for_throughput(is_full_gc, &desired_promo_size, &desired_eden_size);
354
355 } else {
356
357 // Be conservative about reducing the footprint.
358 // Do a minimum number of major collections first.
359 // Have reasonable averages for major and minor collections costs.
360 if (UseAdaptiveSizePolicyFootprintGoal &&
361 young_gen_policy_is_ready() &&
362 avg_major_gc_cost()->average() >= 0.0 &&
363 avg_minor_gc_cost()->average() >= 0.0) {
364 size_t desired_sum = desired_eden_size + desired_promo_size;
365 desired_eden_size = adjust_eden_for_footprint(desired_eden_size,
366 desired_sum);
367 if (is_full_gc) {
368 set_decide_at_full_gc(decide_at_full_gc_true);
369 desired_promo_size = adjust_promo_for_footprint(desired_promo_size,
370 desired_sum);
371 }
372 }
373 }
374
375 // Note we make the same tests as in the code block below; the code
376 // seems a little easier to read with the printing in another block.
377 if (PrintAdaptiveSizePolicy) {
378 if (desired_promo_size > promo_limit) {
379 // "free_in_old_gen" was the original value for used for promo_limit
380 size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
381 gclog_or_tty->print_cr(
382 "PSAdaptiveSizePolicy::compute_generation_free_space limits:"
383 " desired_promo_size: " SIZE_FORMAT
384 " promo_limit: " SIZE_FORMAT
385 " free_in_old_gen: " SIZE_FORMAT
386 " max_old_gen_size: " SIZE_FORMAT
387 " avg_old_live: " SIZE_FORMAT,
388 desired_promo_size, promo_limit, free_in_old_gen,
389 max_old_gen_size, (size_t) avg_old_live()->average());
390 }
391 if (desired_eden_size > eden_limit) {
392 gclog_or_tty->print_cr(
393 "AdaptiveSizePolicy::compute_generation_free_space limits:"
394 " desired_eden_size: " SIZE_FORMAT
395 " old_eden_size: " SIZE_FORMAT
396 " eden_limit: " SIZE_FORMAT
397 " cur_eden: " SIZE_FORMAT
398 " max_eden_size: " SIZE_FORMAT
399 " avg_young_live: " SIZE_FORMAT,
400 desired_eden_size, _eden_size, eden_limit, cur_eden,
401 max_eden_size, (size_t)avg_young_live()->average());
402 }
403 if (gc_cost() > gc_cost_limit) {
404 gclog_or_tty->print_cr(
405 "AdaptiveSizePolicy::compute_generation_free_space: gc time limit"
406 " gc_cost: %f "
407 " GCTimeLimit: %d",
408 gc_cost(), GCTimeLimit);
409 }
410 }
411
412 // Align everything and make a final limit check
413 const size_t alignment = _intra_generation_alignment;
414 desired_eden_size = align_size_up(desired_eden_size, alignment);
415 desired_eden_size = MAX2(desired_eden_size, alignment);
416 desired_promo_size = align_size_up(desired_promo_size, alignment);
417 desired_promo_size = MAX2(desired_promo_size, alignment);
418
419 eden_limit = align_size_down(eden_limit, alignment);
420 promo_limit = align_size_down(promo_limit, alignment);
421
422 // Is too much time being spent in GC?
423 // Is the heap trying to grow beyond it's limits?
424
425 const size_t free_in_old_gen =
426 (size_t)(max_old_gen_size - avg_old_live()->average());
427 if (desired_promo_size > free_in_old_gen && desired_eden_size > eden_limit) {
428 check_gc_overhead_limit(young_live,
429 eden_live,
430 max_old_gen_size,
431 max_eden_size,
432 is_full_gc,
433 gc_cause,
434 collector_policy);
435 }
436
437
438 // And one last limit check, now that we've aligned things.
439 if (desired_eden_size > eden_limit) {
440 // If the policy says to get a larger eden but
441 // is hitting the limit, don't decrease eden.
442 // This can lead to a general drifting down of the
443 // eden size. Let the tenuring calculation push more
444 // into the old gen.
445 desired_eden_size = MAX2(eden_limit, cur_eden);
446 }
447 desired_promo_size = MIN2(desired_promo_size, promo_limit);
448
449
450 if (PrintAdaptiveSizePolicy) {
451 // Timing stats
452 gclog_or_tty->print(
453 "PSAdaptiveSizePolicy::compute_generation_free_space: costs"
454 " minor_time: %f"
455 " major_cost: %f"
456 " mutator_cost: %f"
457 " throughput_goal: %f",
458 minor_gc_cost(), major_gc_cost(), mutator_cost(),
459 _throughput_goal);
460
461 // We give more details if Verbose is set
462 if (Verbose) {
463 gclog_or_tty->print( " minor_pause: %f"
464 " major_pause: %f"
465 " minor_interval: %f"
466 " major_interval: %f"
467 " pause_goal: %f",
468 _avg_minor_pause->padded_average(),
469 _avg_major_pause->padded_average(),
470 _avg_minor_interval->average(),
471 _avg_major_interval->average(),
472 gc_pause_goal_sec());
473 }
474
475 // Footprint stats
476 gclog_or_tty->print( " live_space: " SIZE_FORMAT
477 " free_space: " SIZE_FORMAT,
478 live_space(), free_space());
479 // More detail
480 if (Verbose) {
481 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
482 " avg_young_live: " SIZE_FORMAT
483 " avg_old_live: " SIZE_FORMAT,
484 (size_t)_avg_base_footprint->average(),
485 (size_t)avg_young_live()->average(),
486 (size_t)avg_old_live()->average());
487 }
488
489 // And finally, our old and new sizes.
490 gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT
491 " old_eden_size: " SIZE_FORMAT
492 " desired_promo_size: " SIZE_FORMAT
493 " desired_eden_size: " SIZE_FORMAT,
494 _promo_size, _eden_size,
495 desired_promo_size, desired_eden_size);
496 gclog_or_tty->cr();
497 }
498
499 decay_supplemental_growth(is_full_gc);
500
501 set_promo_size(desired_promo_size);
502 set_eden_size(desired_eden_size);
503 };
504
505 void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) {
506 // Decay the supplemental increment? Decay the supplement growth
507 // factor even if it is not used. It is only meant to give a boost
508 // to the initial growth and if it is not used, then it was not
509 // needed.
510 if (is_full_gc) {
511 // Don't wait for the threshold value for the major collections. If
512 // here, the supplemental growth term was used and should decay.
513 if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay)
514 == 0) {
515 _old_gen_size_increment_supplement =
516 _old_gen_size_increment_supplement >> 1;
517 }
518 } else {
519 if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) &&
520 (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) {
521 _young_gen_size_increment_supplement =
522 _young_gen_size_increment_supplement >> 1;
523 }
524 }
525 }
526
527 void PSAdaptiveSizePolicy::adjust_for_minor_pause_time(bool is_full_gc,
528 size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) {
529
530 // Adjust the young generation size to reduce pause time of
531 // of collections.
532 //
533 // The AdaptiveSizePolicyInitializingSteps test is not used
534 // here. It has not seemed to be needed but perhaps should
535 // be added for consistency.
536 if (minor_pause_young_estimator()->decrement_will_decrease()) {
537 // reduce eden size
538 set_change_young_gen_for_min_pauses(
539 decrease_young_gen_for_min_pauses_true);
540 *desired_eden_size_ptr = *desired_eden_size_ptr -
541 eden_decrement_aligned_down(*desired_eden_size_ptr);
542 } else {
543 // EXPERIMENTAL ADJUSTMENT
544 // Only record that the estimator indicated such an action.
545 // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta;
546 set_change_young_gen_for_min_pauses(
547 increase_young_gen_for_min_pauses_true);
548 }
549 if (PSAdjustTenuredGenForMinorPause) {
550 // If the desired eden size is as small as it will get,
551 // try to adjust the old gen size.
552 if (*desired_eden_size_ptr <= _intra_generation_alignment) {
553 // Vary the old gen size to reduce the young gen pause. This
554 // may not be a good idea. This is just a test.
555 if (minor_pause_old_estimator()->decrement_will_decrease()) {
556 set_change_old_gen_for_min_pauses(
557 decrease_old_gen_for_min_pauses_true);
558 *desired_promo_size_ptr =
559 _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr);
560 } else {
561 set_change_old_gen_for_min_pauses(
562 increase_old_gen_for_min_pauses_true);
563 size_t promo_heap_delta =
564 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
565 if ((*desired_promo_size_ptr + promo_heap_delta) >
566 *desired_promo_size_ptr) {
567 *desired_promo_size_ptr =
568 _promo_size + promo_heap_delta;
569 }
570 }
571 }
572 }
573 }
574
575 void PSAdaptiveSizePolicy::adjust_for_pause_time(bool is_full_gc,
576 size_t* desired_promo_size_ptr,
577 size_t* desired_eden_size_ptr) {
578
579 size_t promo_heap_delta = 0;
580 size_t eden_heap_delta = 0;
581 // Add some checks for a threshhold for a change. For example,
582 // a change less than the required alignment is probably not worth
583 // attempting.
584 if (is_full_gc) {
585 set_decide_at_full_gc(decide_at_full_gc_true);
586 }
587
588 if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
589 adjust_for_minor_pause_time(is_full_gc,
590 desired_promo_size_ptr,
591 desired_eden_size_ptr);
592 // major pause adjustments
593 } else if (is_full_gc) {
594 // Adjust for the major pause time only at full gc's because the
595 // affects of a change can only be seen at full gc's.
596
597 // Reduce old generation size to reduce pause?
598 if (major_pause_old_estimator()->decrement_will_decrease()) {
599 // reduce old generation size
600 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
601 promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr);
602 *desired_promo_size_ptr = _promo_size - promo_heap_delta;
603 } else {
604 // EXPERIMENTAL ADJUSTMENT
605 // Only record that the estimator indicated such an action.
606 // *desired_promo_size_ptr = _promo_size +
607 // promo_increment_aligned_up(*desired_promo_size_ptr);
608 set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true);
609 }
610 if (PSAdjustYoungGenForMajorPause) {
611 // If the promo size is at the minimum (i.e., the old gen
612 // size will not actually decrease), consider changing the
613 // young gen size.
614 if (*desired_promo_size_ptr < _intra_generation_alignment) {
615 // If increasing the young generation will decrease the old gen
616 // pause, do it.
617 // During startup there is noise in the statistics for deciding
618 // on whether to increase or decrease the young gen size. For
619 // some number of iterations, just try to increase the young
620 // gen size if the major pause is too long to try and establish
621 // good statistics for later decisions.
622 if (major_pause_young_estimator()->increment_will_decrease() ||
623 (_young_gen_change_for_major_pause_count
624 <= AdaptiveSizePolicyInitializingSteps)) {
625 set_change_young_gen_for_maj_pauses(
626 increase_young_gen_for_maj_pauses_true);
627 eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr);
628 *desired_eden_size_ptr = _eden_size + eden_heap_delta;
629 _young_gen_change_for_major_pause_count++;
630 } else {
631 // Record that decreasing the young gen size would decrease
632 // the major pause
633 set_change_young_gen_for_maj_pauses(
634 decrease_young_gen_for_maj_pauses_true);
635 eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr);
636 *desired_eden_size_ptr = _eden_size - eden_heap_delta;
637 }
638 }
639 }
640 }
641
642 if (PrintAdaptiveSizePolicy && Verbose) {
643 gclog_or_tty->print_cr(
644 "AdaptiveSizePolicy::compute_generation_free_space "
645 "adjusting gen sizes for major pause (avg %f goal %f). "
646 "desired_promo_size " SIZE_FORMAT "desired_eden_size "
647 SIZE_FORMAT
648 " promo delta " SIZE_FORMAT " eden delta " SIZE_FORMAT,
649 _avg_major_pause->average(), gc_pause_goal_sec(),
650 *desired_promo_size_ptr, *desired_eden_size_ptr,
651 promo_heap_delta, eden_heap_delta);
652 }
653 }
654
655 void PSAdaptiveSizePolicy::adjust_for_throughput(bool is_full_gc,
656 size_t* desired_promo_size_ptr,
657 size_t* desired_eden_size_ptr) {
658
659 // Add some checks for a threshhold for a change. For example,
660 // a change less than the required alignment is probably not worth
661 // attempting.
662 if (is_full_gc) {
663 set_decide_at_full_gc(decide_at_full_gc_true);
664 }
665
666 if ((gc_cost() + mutator_cost()) == 0.0) {
667 return;
668 }
669
670 if (PrintAdaptiveSizePolicy && Verbose) {
671 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_for_throughput("
672 "is_full: %d, promo: " SIZE_FORMAT ", cur_eden: " SIZE_FORMAT "): ",
673 is_full_gc, *desired_promo_size_ptr, *desired_eden_size_ptr);
674 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f "
675 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
676 }
677
678 // Tenured generation
679 if (is_full_gc) {
680
681 // Calculate the change to use for the tenured gen.
682 size_t scaled_promo_heap_delta = 0;
683 // Can the increment to the generation be scaled?
684 if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) {
685 size_t promo_heap_delta =
686 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
687 double scale_by_ratio = major_gc_cost() / gc_cost();
688 scaled_promo_heap_delta =
689 (size_t) (scale_by_ratio * (double) promo_heap_delta);
690 if (PrintAdaptiveSizePolicy && Verbose) {
691 gclog_or_tty->print_cr(
692 "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
693 SIZE_FORMAT,
694 promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta);
695 }
696 } else if (major_gc_cost() >= 0.0) {
697 // Scaling is not going to work. If the major gc time is the
698 // larger, give it a full increment.
699 if (major_gc_cost() >= minor_gc_cost()) {
700 scaled_promo_heap_delta =
701 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
702 }
703 } else {
704 // Don't expect to get here but it's ok if it does
705 // in the product build since the delta will be 0
706 // and nothing will change.
707 assert(false, "Unexpected value for gc costs");
708 }
709
710 switch (AdaptiveSizeThroughPutPolicy) {
711 case 1:
712 // Early in the run the statistics might not be good. Until
713 // a specific number of collections have been, use the heuristic
714 // that a larger generation size means lower collection costs.
715 if (major_collection_estimator()->increment_will_decrease() ||
716 (_old_gen_change_for_major_throughput
717 <= AdaptiveSizePolicyInitializingSteps)) {
718 // Increase tenured generation size to reduce major collection cost
719 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
720 *desired_promo_size_ptr) {
721 *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta;
722 }
723 set_change_old_gen_for_throughput(
724 increase_old_gen_for_throughput_true);
725 _old_gen_change_for_major_throughput++;
726 } else {
727 // EXPERIMENTAL ADJUSTMENT
728 // Record that decreasing the old gen size would decrease
729 // the major collection cost but don't do it.
730 // *desired_promo_size_ptr = _promo_size -
731 // promo_decrement_aligned_down(*desired_promo_size_ptr);
732 set_change_old_gen_for_throughput(
733 decrease_old_gen_for_throughput_true);
734 }
735
736 break;
737 default:
738 // Simplest strategy
739 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
740 *desired_promo_size_ptr) {
741 *desired_promo_size_ptr = *desired_promo_size_ptr +
742 scaled_promo_heap_delta;
743 }
744 set_change_old_gen_for_throughput(
745 increase_old_gen_for_throughput_true);
746 _old_gen_change_for_major_throughput++;
747 }
748
749 if (PrintAdaptiveSizePolicy && Verbose) {
750 gclog_or_tty->print_cr(
751 "adjusting tenured gen for throughput (avg %f goal %f). "
752 "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT ,
753 mutator_cost(), _throughput_goal,
754 *desired_promo_size_ptr, scaled_promo_heap_delta);
755 }
756 }
757
758 // Young generation
759 size_t scaled_eden_heap_delta = 0;
760 // Can the increment to the generation be scaled?
761 if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) {
762 size_t eden_heap_delta =
763 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
764 double scale_by_ratio = minor_gc_cost() / gc_cost();
765 assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong");
766 scaled_eden_heap_delta =
767 (size_t) (scale_by_ratio * (double) eden_heap_delta);
768 if (PrintAdaptiveSizePolicy && Verbose) {
769 gclog_or_tty->print_cr(
770 "Scaled eden increment: " SIZE_FORMAT " by %f down to "
771 SIZE_FORMAT,
772 eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta);
773 }
774 } else if (minor_gc_cost() >= 0.0) {
775 // Scaling is not going to work. If the minor gc time is the
776 // larger, give it a full increment.
777 if (minor_gc_cost() > major_gc_cost()) {
778 scaled_eden_heap_delta =
779 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
780 }
781 } else {
782 // Don't expect to get here but it's ok if it does
783 // in the product build since the delta will be 0
784 // and nothing will change.
785 assert(false, "Unexpected value for gc costs");
786 }
787
788 // Use a heuristic for some number of collections to give
789 // the averages time to settle down.
790 switch (AdaptiveSizeThroughPutPolicy) {
791 case 1:
792 if (minor_collection_estimator()->increment_will_decrease() ||
793 (_young_gen_change_for_minor_throughput
794 <= AdaptiveSizePolicyInitializingSteps)) {
795 // Expand young generation size to reduce frequency of
796 // of collections.
797 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
798 *desired_eden_size_ptr) {
799 *desired_eden_size_ptr =
800 *desired_eden_size_ptr + scaled_eden_heap_delta;
801 }
802 set_change_young_gen_for_throughput(
803 increase_young_gen_for_througput_true);
804 _young_gen_change_for_minor_throughput++;
805 } else {
806 // EXPERIMENTAL ADJUSTMENT
807 // Record that decreasing the young gen size would decrease
808 // the minor collection cost but don't do it.
809 // *desired_eden_size_ptr = _eden_size -
810 // eden_decrement_aligned_down(*desired_eden_size_ptr);
811 set_change_young_gen_for_throughput(
812 decrease_young_gen_for_througput_true);
813 }
814 break;
815 default:
816 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
817 *desired_eden_size_ptr) {
818 *desired_eden_size_ptr =
819 *desired_eden_size_ptr + scaled_eden_heap_delta;
820 }
821 set_change_young_gen_for_throughput(
822 increase_young_gen_for_througput_true);
823 _young_gen_change_for_minor_throughput++;
824 }
825
826 if (PrintAdaptiveSizePolicy && Verbose) {
827 gclog_or_tty->print_cr(
828 "adjusting eden for throughput (avg %f goal %f). desired_eden_size "
829 SIZE_FORMAT " eden delta " SIZE_FORMAT "\n",
830 mutator_cost(), _throughput_goal,
831 *desired_eden_size_ptr, scaled_eden_heap_delta);
832 }
833 }
834
835 size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint(
836 size_t desired_promo_size, size_t desired_sum) {
837 assert(desired_promo_size <= desired_sum, "Inconsistent parameters");
838 set_decrease_for_footprint(decrease_old_gen_for_footprint_true);
839
840 size_t change = promo_decrement(desired_promo_size);
841 change = scale_down(change, desired_promo_size, desired_sum);
842
843 size_t reduced_size = desired_promo_size - change;
844
845 if (PrintAdaptiveSizePolicy && Verbose) {
846 gclog_or_tty->print_cr(
847 "AdaptiveSizePolicy::compute_generation_free_space "
848 "adjusting tenured gen for footprint. "
849 "starting promo size " SIZE_FORMAT
850 " reduced promo size " SIZE_FORMAT,
851 " promo delta " SIZE_FORMAT,
852 desired_promo_size, reduced_size, change );
853 }
854
855 assert(reduced_size <= desired_promo_size, "Inconsistent result");
856 return reduced_size;
857 }
858
859 size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint(
860 size_t desired_eden_size, size_t desired_sum) {
861 assert(desired_eden_size <= desired_sum, "Inconsistent parameters");
862 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
863
864 size_t change = eden_decrement(desired_eden_size);
865 change = scale_down(change, desired_eden_size, desired_sum);
866
867 size_t reduced_size = desired_eden_size - change;
868
869 if (PrintAdaptiveSizePolicy && Verbose) {
870 gclog_or_tty->print_cr(
871 "AdaptiveSizePolicy::compute_generation_free_space "
872 "adjusting eden for footprint. "
873 " starting eden size " SIZE_FORMAT
874 " reduced eden size " SIZE_FORMAT
875 " eden delta " SIZE_FORMAT,
876 desired_eden_size, reduced_size, change);
877 }
878
879 assert(reduced_size <= desired_eden_size, "Inconsistent result");
880 return reduced_size;
881 }
882
883 // Scale down "change" by the factor
884 // part / total
885 // Don't align the results.
886
887 size_t PSAdaptiveSizePolicy::scale_down(size_t change,
888 double part,
889 double total) {
890 assert(part <= total, "Inconsistent input");
891 size_t reduced_change = change;
892 if (total > 0) {
893 double fraction = part / total;
894 reduced_change = (size_t) (fraction * (double) change);
895 }
896 assert(reduced_change <= change, "Inconsistent result");
897 return reduced_change;
898 }
899
900 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden,
901 uint percent_change) {
902 size_t eden_heap_delta;
903 eden_heap_delta = cur_eden / 100 * percent_change;
904 return eden_heap_delta;
905 }
906
907 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) {
908 return eden_increment(cur_eden, YoungGenerationSizeIncrement);
909 }
910
911 size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
912 size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement);
913 return align_size_up(result, _intra_generation_alignment);
914 }
915
916 size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) {
917 size_t result = eden_increment(cur_eden);
918 return align_size_down(result, _intra_generation_alignment);
919 }
920
921 size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up(
922 size_t cur_eden) {
923 size_t result = eden_increment(cur_eden,
924 YoungGenerationSizeIncrement + _young_gen_size_increment_supplement);
925 return align_size_up(result, _intra_generation_alignment);
926 }
927
928 size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
929 size_t eden_heap_delta = eden_decrement(cur_eden);
930 return align_size_down(eden_heap_delta, _intra_generation_alignment);
931 }
932
933 size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
934 size_t eden_heap_delta = eden_increment(cur_eden) /
935 AdaptiveSizeDecrementScaleFactor;
936 return eden_heap_delta;
937 }
938
939 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo,
940 uint percent_change) {
941 size_t promo_heap_delta;
942 promo_heap_delta = cur_promo / 100 * percent_change;
943 return promo_heap_delta;
944 }
945
946 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) {
947 return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
948 }
949
950 size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
951 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
952 return align_size_up(result, _intra_generation_alignment);
953 }
954
955 size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) {
956 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement);
957 return align_size_down(result, _intra_generation_alignment);
958 }
959
960 size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up(
961 size_t cur_promo) {
962 size_t result = promo_increment(cur_promo,
963 TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement);
964 return align_size_up(result, _intra_generation_alignment);
965 }
966
967 size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
968 size_t promo_heap_delta = promo_decrement(cur_promo);
969 return align_size_down(promo_heap_delta, _intra_generation_alignment);
970 }
971
972 size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
973 size_t promo_heap_delta = promo_increment(cur_promo);
974 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
975 return promo_heap_delta;
976 }
977
978 int PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
979 bool is_survivor_overflow,
980 int tenuring_threshold,
981 size_t survivor_limit) {
982 assert(survivor_limit >= _intra_generation_alignment,
983 "survivor_limit too small");
984 assert((size_t)align_size_down(survivor_limit, _intra_generation_alignment)
985 == survivor_limit, "survivor_limit not aligned");
986
987 // This method is called even if the tenuring threshold and survivor
988 // spaces are not adjusted so that the averages are sampled above.
989 if (!UsePSAdaptiveSurvivorSizePolicy ||
990 !young_gen_policy_is_ready()) {
991 return tenuring_threshold;
992 }
993
994 // We'll decide whether to increase or decrease the tenuring
995 // threshold based partly on the newly computed survivor size
996 // (if we hit the maximum limit allowed, we'll always choose to
997 // decrement the threshold).
998 bool incr_tenuring_threshold = false;
999 bool decr_tenuring_threshold = false;
1000
1001 set_decrement_tenuring_threshold_for_gc_cost(false);
1002 set_increment_tenuring_threshold_for_gc_cost(false);
1003 set_decrement_tenuring_threshold_for_survivor_limit(false);
1004
1005 if (!is_survivor_overflow) {
1006 // Keep running averages on how much survived
1007
1008 // We use the tenuring threshold to equalize the cost of major
1009 // and minor collections.
1010 // ThresholdTolerance is used to indicate how sensitive the
1011 // tenuring threshold is to differences in cost betweent the
1012 // collection types.
1013
1014 // Get the times of interest. This involves a little work, so
1015 // we cache the values here.
1016 const double major_cost = major_gc_cost();
1017 const double minor_cost = minor_gc_cost();
1018
1019 if (minor_cost > major_cost * _threshold_tolerance_percent) {
1020 // Minor times are getting too long; lower the threshold so
1021 // less survives and more is promoted.
1022 decr_tenuring_threshold = true;
1023 set_decrement_tenuring_threshold_for_gc_cost(true);
1024 } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
1025 // Major times are too long, so we want less promotion.
1026 incr_tenuring_threshold = true;
1027 set_increment_tenuring_threshold_for_gc_cost(true);
1028 }
1029
1030 } else {
1031 // Survivor space overflow occurred, so promoted and survived are
1032 // not accurate. We'll make our best guess by combining survived
1033 // and promoted and count them as survivors.
1034 //
1035 // We'll lower the tenuring threshold to see if we can correct
1036 // things. Also, set the survivor size conservatively. We're
1037 // trying to avoid many overflows from occurring if defnew size
1038 // is just too small.
1039
1040 decr_tenuring_threshold = true;
1041 }
1042
1043 // The padded average also maintains a deviation from the average;
1044 // we use this to see how good of an estimate we have of what survived.
1045 // We're trying to pad the survivor size as little as possible without
1046 // overflowing the survivor spaces.
1047 size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
1048 _intra_generation_alignment);
1049 target_size = MAX2(target_size, _intra_generation_alignment);
1050
1051 if (target_size > survivor_limit) {
1052 // Target size is bigger than we can handle. Let's also reduce
1053 // the tenuring threshold.
1054 target_size = survivor_limit;
1055 decr_tenuring_threshold = true;
1056 set_decrement_tenuring_threshold_for_survivor_limit(true);
1057 }
1058
1059 // Finally, increment or decrement the tenuring threshold, as decided above.
1060 // We test for decrementing first, as we might have hit the target size
1061 // limit.
1062 if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1063 if (tenuring_threshold > 1) {
1064 tenuring_threshold--;
1065 }
1066 } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1067 if (tenuring_threshold < MaxTenuringThreshold) {
1068 tenuring_threshold++;
1069 }
1070 }
1071
1072 // We keep a running average of the amount promoted which is used
1073 // to decide when we should collect the old generation (when
1074 // the amount of old gen free space is less than what we expect to
1075 // promote).
1076
1077 if (PrintAdaptiveSizePolicy) {
1078 // A little more detail if Verbose is on
1079 if (Verbose) {
1080 gclog_or_tty->print( " avg_survived: %f"
1081 " avg_deviation: %f",
1082 _avg_survived->average(),
1083 _avg_survived->deviation());
1084 }
1085
1086 gclog_or_tty->print( " avg_survived_padded_avg: %f",
1087 _avg_survived->padded_average());
1088
1089 if (Verbose) {
1090 gclog_or_tty->print( " avg_promoted_avg: %f"
1091 " avg_promoted_dev: %f",
1092 avg_promoted()->average(),
1093 avg_promoted()->deviation());
1094 }
1095
1096 gclog_or_tty->print( " avg_promoted_padded_avg: %f"
1097 " avg_pretenured_padded_avg: %f"
1098 " tenuring_thresh: %d"
1099 " target_size: " SIZE_FORMAT,
1100 avg_promoted()->padded_average(),
1101 _avg_pretenured->padded_average(),
1102 tenuring_threshold, target_size);
1103 tty->cr();
1104 }
1105
1106 set_survivor_size(target_size);
1107
1108 return tenuring_threshold;
1109 }
1110
1111 void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow,
1112 size_t survived,
1113 size_t promoted) {
1114 // Update averages
1115 if (!is_survivor_overflow) {
1116 // Keep running averages on how much survived
1117 _avg_survived->sample(survived);
1118 } else {
1119 size_t survived_guess = survived + promoted;
1120 _avg_survived->sample(survived_guess);
1121 }
1122 avg_promoted()->sample(promoted + _avg_pretenured->padded_average());
1123
1124 if (PrintAdaptiveSizePolicy) {
1125 gclog_or_tty->print(
1126 "AdaptiveSizePolicy::compute_survivor_space_size_and_thresh:"
1127 " survived: " SIZE_FORMAT
1128 " promoted: " SIZE_FORMAT
1129 " overflow: %s",
1130 survived, promoted, is_survivor_overflow ? "true" : "false");
1131 }
1132 }
1133
1134 bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st)
1135 const {
1136
1137 if (!UseAdaptiveSizePolicy) return false;
1138
1139 return AdaptiveSizePolicy::print_adaptive_size_policy_on(
1140 st,
1141 PSScavenge::tenuring_threshold());
1142 }
1143
1144 #ifndef PRODUCT
1145
1146 void TestOldFreeSpaceCalculation_test() {
1147 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 20) == 25, "Calculation of free memory failed");
1148 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 50) == 100, "Calculation of free memory failed");
1149 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 60) == 150, "Calculation of free memory failed");
1150 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(100, 75) == 300, "Calculation of free memory failed");
1151 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 20) == 100, "Calculation of free memory failed");
1152 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 50) == 400, "Calculation of free memory failed");
1153 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 60) == 600, "Calculation of free memory failed");
1154 assert(PSAdaptiveSizePolicy::calculate_free_based_on_live(400, 75) == 1200, "Calculation of free memory failed");
1155 }
1156
1157 #endif /* !PRODUCT */