1 /*
2 * Copyright (c) 2004, 2018, 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/shared/adaptiveSizePolicy.hpp"
27 #include "gc/shared/collectorPolicy.hpp"
28 #include "gc/shared/gcCause.hpp"
29 #include "gc/shared/gcUtil.inline.hpp"
30 #include "gc/shared/workgroup.hpp"
31 #include "logging/log.hpp"
32 #include "runtime/timer.hpp"
33 #include "utilities/ostream.hpp"
34
35 elapsedTimer AdaptiveSizePolicy::_minor_timer;
36 elapsedTimer AdaptiveSizePolicy::_major_timer;
37 bool AdaptiveSizePolicy::_debug_perturbation = false;
38
39 // The throughput goal is implemented as
40 // _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
41 // gc_cost_ratio is the ratio
42 // application cost / gc cost
43 // For example a gc_cost_ratio of 4 translates into a
44 // throughput goal of .80
45
46 AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
47 size_t init_promo_size,
48 size_t init_survivor_size,
49 double gc_pause_goal_sec,
50 uint gc_cost_ratio) :
51 _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
52 _eden_size(init_eden_size),
53 _promo_size(init_promo_size),
54 _survivor_size(init_survivor_size),
55 _latest_minor_mutator_interval_seconds(0),
56 _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
57 _gc_pause_goal_sec(gc_pause_goal_sec),
58 _young_gen_change_for_minor_throughput(0),
59 _old_gen_change_for_major_throughput(0) {
60 assert(AdaptiveSizePolicyGCTimeLimitThreshold > 0,
61 "No opportunity to clear SoftReferences before GC overhead limit");
62 _avg_minor_pause =
63 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
64 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
65 _avg_minor_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
66 _avg_major_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
67
68 _avg_young_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
69 _avg_old_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
70 _avg_eden_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
71
72 _avg_survived = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
73 SurvivorPadding);
74 _avg_pretenured = new AdaptivePaddedNoZeroDevAverage(
75 AdaptiveSizePolicyWeight,
76 SurvivorPadding);
77
78 _minor_pause_old_estimator =
79 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
80 _minor_pause_young_estimator =
81 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
82 _minor_collection_estimator =
83 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
84 _major_collection_estimator =
85 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
86
87 // Start the timers
88 _minor_timer.start();
89
90 _young_gen_policy_is_ready = false;
91 }
92
93 // If the number of GC threads was set on the command line,
94 // use it.
95 // Else
96 // Calculate the number of GC threads based on the number of Java threads.
97 // Calculate the number of GC threads based on the size of the heap.
98 // Use the larger.
99
100 uint AdaptiveSizePolicy::calc_default_active_workers(uintx total_workers,
101 const uintx min_workers,
102 uintx active_workers,
103 uintx application_workers) {
104 // If the user has specifically set the number of
105 // GC threads, use them.
106
107 // If the user has turned off using a dynamic number of GC threads
108 // or the users has requested a specific number, set the active
109 // number of workers to all the workers.
110
111 uintx new_active_workers = total_workers;
112 uintx prev_active_workers = active_workers;
113 uintx active_workers_by_JT = 0;
114 uintx active_workers_by_heap_size = 0;
115
116 // Always use at least min_workers but use up to
117 // GCThreadsPerJavaThreads * application threads.
118 active_workers_by_JT =
119 MAX2((uintx) GCWorkersPerJavaThread * application_workers,
120 min_workers);
121
122 // Choose a number of GC threads based on the current size
123 // of the heap. This may be complicated because the size of
124 // the heap depends on factors such as the throughput goal.
125 // Still a large heap should be collected by more GC threads.
126 active_workers_by_heap_size =
127 MAX2((size_t) 2U, Universe::heap()->capacity() / HeapSizePerGCThread);
128
129 uintx max_active_workers =
130 MAX2(active_workers_by_JT, active_workers_by_heap_size);
131
132 new_active_workers = MIN2(max_active_workers, (uintx) total_workers);
133
134 // Increase GC workers instantly but decrease them more
135 // slowly.
136 if (new_active_workers < prev_active_workers) {
137 new_active_workers =
138 MAX2(min_workers, (prev_active_workers + new_active_workers) / 2);
139 }
140
141 // Check once more that the number of workers is within the limits.
142 assert(min_workers <= total_workers, "Minimum workers not consistent with total workers");
143 assert(new_active_workers >= min_workers, "Minimum workers not observed");
144 assert(new_active_workers <= total_workers, "Total workers not observed");
145
146 if (ForceDynamicNumberOfGCThreads) {
147 // Assume this is debugging and jiggle the number of GC threads.
148 if (new_active_workers == prev_active_workers) {
149 if (new_active_workers < total_workers) {
150 new_active_workers++;
151 } else if (new_active_workers > min_workers) {
152 new_active_workers--;
153 }
154 }
155 if (new_active_workers == total_workers) {
156 if (_debug_perturbation) {
157 new_active_workers = min_workers;
158 }
159 _debug_perturbation = !_debug_perturbation;
160 }
161 assert((new_active_workers <= ParallelGCThreads) &&
162 (new_active_workers >= min_workers),
163 "Jiggled active workers too much");
164 }
165
166 log_trace(gc, task)("GCTaskManager::calc_default_active_workers() : "
167 "active_workers(): " UINTX_FORMAT " new_active_workers: " UINTX_FORMAT " "
168 "prev_active_workers: " UINTX_FORMAT "\n"
169 " active_workers_by_JT: " UINTX_FORMAT " active_workers_by_heap_size: " UINTX_FORMAT,
170 active_workers, new_active_workers, prev_active_workers,
171 active_workers_by_JT, active_workers_by_heap_size);
172 assert(new_active_workers > 0, "Always need at least 1");
173 return new_active_workers;
174 }
175
176 uint AdaptiveSizePolicy::calc_active_workers(uintx total_workers,
177 uintx active_workers,
178 uintx application_workers) {
179 // If the user has specifically set the number of
180 // GC threads, use them.
181
182 // If the user has turned off using a dynamic number of GC threads
183 // or the users has requested a specific number, set the active
184 // number of workers to all the workers.
185
186 uint new_active_workers;
187 if (!UseDynamicNumberOfGCThreads ||
188 (!FLAG_IS_DEFAULT(ParallelGCThreads) && !ForceDynamicNumberOfGCThreads)) {
189 new_active_workers = total_workers;
190 } else {
191 uintx min_workers = (total_workers == 1) ? 1 : 2;
192 new_active_workers = calc_default_active_workers(total_workers,
193 min_workers,
194 active_workers,
195 application_workers);
196 }
197 assert(new_active_workers > 0, "Always need at least 1");
198 return new_active_workers;
199 }
200
201 uint AdaptiveSizePolicy::calc_active_conc_workers(uintx total_workers,
202 uintx active_workers,
203 uintx application_workers) {
204 if (!UseDynamicNumberOfGCThreads ||
205 (!FLAG_IS_DEFAULT(ConcGCThreads) && !ForceDynamicNumberOfGCThreads)) {
206 return ConcGCThreads;
207 } else {
208 uint no_of_gc_threads = calc_default_active_workers(total_workers,
209 1, /* Minimum number of workers */
210 active_workers,
211 application_workers);
212 return no_of_gc_threads;
213 }
214 }
215
216 bool AdaptiveSizePolicy::tenuring_threshold_change() const {
217 return decrement_tenuring_threshold_for_gc_cost() ||
218 increment_tenuring_threshold_for_gc_cost() ||
219 decrement_tenuring_threshold_for_survivor_limit();
220 }
221
222 void AdaptiveSizePolicy::minor_collection_begin() {
223 // Update the interval time
224 _minor_timer.stop();
225 // Save most recent collection time
226 _latest_minor_mutator_interval_seconds = _minor_timer.seconds();
227 _minor_timer.reset();
228 _minor_timer.start();
229 }
230
231 void AdaptiveSizePolicy::update_minor_pause_young_estimator(
232 double minor_pause_in_ms) {
233 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
234 _minor_pause_young_estimator->update(eden_size_in_mbytes,
235 minor_pause_in_ms);
236 }
237
238 void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) {
239 // Update the pause time.
240 _minor_timer.stop();
241
242 if (!GCCause::is_user_requested_gc(gc_cause) ||
243 UseAdaptiveSizePolicyWithSystemGC) {
244 double minor_pause_in_seconds = _minor_timer.seconds();
245 double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS;
246
247 // Sample for performance counter
248 _avg_minor_pause->sample(minor_pause_in_seconds);
249
250 // Cost of collection (unit-less)
251 double collection_cost = 0.0;
252 if ((_latest_minor_mutator_interval_seconds > 0.0) &&
253 (minor_pause_in_seconds > 0.0)) {
254 double interval_in_seconds =
255 _latest_minor_mutator_interval_seconds + minor_pause_in_seconds;
256 collection_cost =
257 minor_pause_in_seconds / interval_in_seconds;
258 _avg_minor_gc_cost->sample(collection_cost);
259 // Sample for performance counter
260 _avg_minor_interval->sample(interval_in_seconds);
261 }
262
263 // The policy does not have enough data until at least some
264 // young collections have been done.
265 _young_gen_policy_is_ready =
266 (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold);
267
268 // Calculate variables used to estimate pause time vs. gen sizes
269 double eden_size_in_mbytes = ((double)_eden_size) / ((double)M);
270 update_minor_pause_young_estimator(minor_pause_in_ms);
271 update_minor_pause_old_estimator(minor_pause_in_ms);
272
273 log_trace(gc, ergo)("AdaptiveSizePolicy::minor_collection_end: minor gc cost: %f average: %f",
274 collection_cost, _avg_minor_gc_cost->average());
275 log_trace(gc, ergo)(" minor pause: %f minor period %f",
276 minor_pause_in_ms, _latest_minor_mutator_interval_seconds * MILLIUNITS);
277
278 // Calculate variable used to estimate collection cost vs. gen sizes
279 assert(collection_cost >= 0.0, "Expected to be non-negative");
280 _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost);
281 }
282
283 // Interval times use this timer to measure the mutator time.
284 // Reset the timer after the GC pause.
285 _minor_timer.reset();
286 _minor_timer.start();
287 }
288
289 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden, uint percent_change) {
290 size_t eden_heap_delta;
291 eden_heap_delta = cur_eden / 100 * percent_change;
292 return eden_heap_delta;
293 }
294
295 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) {
296 return eden_increment(cur_eden, YoungGenerationSizeIncrement);
297 }
298
299 size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
300 size_t eden_heap_delta = eden_increment(cur_eden) /
301 AdaptiveSizeDecrementScaleFactor;
302 return eden_heap_delta;
303 }
304
305 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo, uint percent_change) {
306 size_t promo_heap_delta;
307 promo_heap_delta = cur_promo / 100 * percent_change;
308 return promo_heap_delta;
309 }
310
311 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) {
312 return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
313 }
314
315 size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
316 size_t promo_heap_delta = promo_increment(cur_promo);
317 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
318 return promo_heap_delta;
319 }
320
321 double AdaptiveSizePolicy::time_since_major_gc() const {
322 _major_timer.stop();
323 double result = _major_timer.seconds();
324 _major_timer.start();
325 return result;
326 }
327
328 // Linear decay of major gc cost
329 double AdaptiveSizePolicy::decaying_major_gc_cost() const {
330 double major_interval = major_gc_interval_average_for_decay();
331 double major_gc_cost_average = major_gc_cost();
332 double decayed_major_gc_cost = major_gc_cost_average;
333 if(time_since_major_gc() > 0.0) {
334 decayed_major_gc_cost = major_gc_cost() *
335 (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval)
336 / time_since_major_gc();
337 }
338
339 // The decayed cost should always be smaller than the
340 // average cost but the vagaries of finite arithmetic could
341 // produce a larger value in decayed_major_gc_cost so protect
342 // against that.
343 return MIN2(major_gc_cost_average, decayed_major_gc_cost);
344 }
345
346 // Use a value of the major gc cost that has been decayed
347 // by the factor
348 //
349 // average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale /
350 // time-since-last-major-gc
351 //
352 // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale
353 // is less than time-since-last-major-gc.
354 //
355 // In cases where there are initial major gc's that
356 // are of a relatively high cost but no later major
357 // gc's, the total gc cost can remain high because
358 // the major gc cost remains unchanged (since there are no major
359 // gc's). In such a situation the value of the unchanging
360 // major gc cost can keep the mutator throughput below
361 // the goal when in fact the major gc cost is becoming diminishingly
362 // small. Use the decaying gc cost only to decide whether to
363 // adjust for throughput. Using it also to determine the adjustment
364 // to be made for throughput also seems reasonable but there is
365 // no test case to use to decide if it is the right thing to do
366 // don't do it yet.
367
368 double AdaptiveSizePolicy::decaying_gc_cost() const {
369 double decayed_major_gc_cost = major_gc_cost();
370 double avg_major_interval = major_gc_interval_average_for_decay();
371 if (UseAdaptiveSizeDecayMajorGCCost &&
372 (AdaptiveSizeMajorGCDecayTimeScale > 0) &&
373 (avg_major_interval > 0.00)) {
374 double time_since_last_major_gc = time_since_major_gc();
375
376 // Decay the major gc cost?
377 if (time_since_last_major_gc >
378 ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) {
379
380 // Decay using the time-since-last-major-gc
381 decayed_major_gc_cost = decaying_major_gc_cost();
382 log_trace(gc, ergo)("decaying_gc_cost: major interval average: %f time since last major gc: %f",
383 avg_major_interval, time_since_last_major_gc);
384 log_trace(gc, ergo)(" major gc cost: %f decayed major gc cost: %f",
385 major_gc_cost(), decayed_major_gc_cost);
386 }
387 }
388 double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
389 return result;
390 }
391
392
393 void AdaptiveSizePolicy::clear_generation_free_space_flags() {
394 set_change_young_gen_for_min_pauses(0);
395 set_change_old_gen_for_maj_pauses(0);
396
397 set_change_old_gen_for_throughput(0);
398 set_change_young_gen_for_throughput(0);
399 set_decrease_for_footprint(0);
400 set_decide_at_full_gc(0);
401 }
402
403 class AdaptiveSizePolicyTimeOverheadTester: public OverheadTester {
404 double _gc_cost;
405
406 public:
407 AdaptiveSizePolicyTimeOverheadTester(double gc_cost) : _gc_cost(gc_cost) {}
408
409 bool is_exceeded() {
410 // Note that the gc time limit test only works for the collections
411 // of the young gen + tenured gen and not for collections of the
412 // permanent gen. That is because the calculation of the space
413 // freed by the collection is the free space in the young gen +
414 // tenured gen.
415 return _gc_cost > (GCTimeLimit / 100.0);
416 }
417 };
418
419 class AdaptiveSizePolicySpaceOverheadTester: public OverheadTester {
420 size_t _eden_live;
421 size_t _max_old_gen_size;
422 size_t _max_eden_size;
423 size_t _promo_size;
424 double _avg_eden_live;
425 double _avg_old_live;
426
427 public:
428 AdaptiveSizePolicySpaceOverheadTester(size_t eden_live,
429 size_t max_old_gen_size,
430 size_t max_eden_size,
431 size_t promo_size,
432 double avg_eden_live,
433 double avg_old_live) :
434 _eden_live(eden_live),
435 _max_old_gen_size(max_old_gen_size),
436 _max_eden_size(max_eden_size),
437 _promo_size(promo_size),
438 _avg_eden_live(avg_eden_live),
439 _avg_old_live(avg_old_live) {}
440
441 bool is_exceeded() {
442 // _max_eden_size is the upper limit on the size of eden based on
443 // the maximum size of the young generation and the sizes
444 // of the survivor space.
445 // The question being asked is whether the space being recovered by
446 // a collection is low.
447 // free_in_eden is the free space in eden after a collection and
448 // free_in_old_gen is the free space in the old generation after
449 // a collection.
450 //
451 // Use the minimum of the current value of the live in eden
452 // or the average of the live in eden.
453 // If the current value drops quickly, that should be taken
454 // into account (i.e., don't trigger if the amount of free
455 // space has suddenly jumped up). If the current is much
456 // higher than the average, use the average since it represents
457 // the longer term behavior.
458 const size_t live_in_eden =
459 MIN2(_eden_live, (size_t)_avg_eden_live);
460 const size_t free_in_eden = _max_eden_size > live_in_eden ?
461 _max_eden_size - live_in_eden : 0;
462 const size_t free_in_old_gen = (size_t)(_max_old_gen_size - _avg_old_live);
463 const size_t total_free_limit = free_in_old_gen + free_in_eden;
464 const size_t total_mem = _max_old_gen_size + _max_eden_size;
465 const double free_limit_ratio = GCHeapFreeLimit / 100.0;
466 const double mem_free_limit = total_mem * free_limit_ratio;
467 const double mem_free_old_limit = _max_old_gen_size * free_limit_ratio;
468 const double mem_free_eden_limit = _max_eden_size * free_limit_ratio;
469 size_t promo_limit = (size_t)(_max_old_gen_size - _avg_old_live);
470 // But don't force a promo size below the current promo size. Otherwise,
471 // the promo size will shrink for no good reason.
472 promo_limit = MAX2(promo_limit, _promo_size);
473
474 log_trace(gc, ergo)(
475 "AdaptiveSizePolicySpaceOverheadTester::is_exceeded:"
476 " promo_limit: " SIZE_FORMAT
477 " max_eden_size: " SIZE_FORMAT
478 " total_free_limit: " SIZE_FORMAT
479 " max_old_gen_size: " SIZE_FORMAT
480 " max_eden_size: " SIZE_FORMAT
481 " mem_free_limit: " SIZE_FORMAT,
482 promo_limit, _max_eden_size, total_free_limit,
483 _max_old_gen_size, _max_eden_size,
484 (size_t)mem_free_limit);
485
486 return free_in_old_gen < (size_t)mem_free_old_limit &&
487 free_in_eden < (size_t)mem_free_eden_limit;
488 }
489
490 };
491
492 void AdaptiveSizePolicy::check_gc_overhead_limit(
493 size_t eden_live,
494 size_t max_old_gen_size,
495 size_t max_eden_size,
496 bool is_full_gc,
497 GCCause::Cause gc_cause,
498 SoftRefPolicy* soft_ref_policy) {
499
500 AdaptiveSizePolicyTimeOverheadTester time_overhead(gc_cost());
501 AdaptiveSizePolicySpaceOverheadTester space_overhead(eden_live,
502 max_old_gen_size,
503 max_eden_size,
504 _promo_size,
505 avg_eden_live()->average(),
506 avg_old_live()->average());
507 _overhead_checker.check_gc_overhead_limit(&time_overhead,
508 &space_overhead,
509 is_full_gc,
510 gc_cause,
511 soft_ref_policy);
512 }
513 // Printing
514
515 bool AdaptiveSizePolicy::print() const {
516 assert(UseAdaptiveSizePolicy, "UseAdaptiveSizePolicy need to be enabled.");
517
518 if (!log_is_enabled(Debug, gc, ergo)) {
519 return false;
520 }
521
522 // Print goal for which action is needed.
523 char* action = NULL;
524 bool change_for_pause = false;
525 if ((change_old_gen_for_maj_pauses() ==
526 decrease_old_gen_for_maj_pauses_true) ||
527 (change_young_gen_for_min_pauses() ==
528 decrease_young_gen_for_min_pauses_true)) {
529 action = (char*) " *** pause time goal ***";
530 change_for_pause = true;
531 } else if ((change_old_gen_for_throughput() ==
532 increase_old_gen_for_throughput_true) ||
533 (change_young_gen_for_throughput() ==
534 increase_young_gen_for_througput_true)) {
535 action = (char*) " *** throughput goal ***";
536 } else if (decrease_for_footprint()) {
537 action = (char*) " *** reduced footprint ***";
538 } else {
539 // No actions were taken. This can legitimately be the
540 // situation if not enough data has been gathered to make
541 // decisions.
542 return false;
543 }
544
545 // Pauses
546 // Currently the size of the old gen is only adjusted to
547 // change the major pause times.
548 char* young_gen_action = NULL;
549 char* tenured_gen_action = NULL;
550
551 char* shrink_msg = (char*) "(attempted to shrink)";
552 char* grow_msg = (char*) "(attempted to grow)";
553 char* no_change_msg = (char*) "(no change)";
554 if (change_young_gen_for_min_pauses() ==
555 decrease_young_gen_for_min_pauses_true) {
556 young_gen_action = shrink_msg;
557 } else if (change_for_pause) {
558 young_gen_action = no_change_msg;
559 }
560
561 if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) {
562 tenured_gen_action = shrink_msg;
563 } else if (change_for_pause) {
564 tenured_gen_action = no_change_msg;
565 }
566
567 // Throughput
568 if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) {
569 assert(change_young_gen_for_throughput() ==
570 increase_young_gen_for_througput_true,
571 "Both generations should be growing");
572 young_gen_action = grow_msg;
573 tenured_gen_action = grow_msg;
574 } else if (change_young_gen_for_throughput() ==
575 increase_young_gen_for_througput_true) {
576 // Only the young generation may grow at start up (before
577 // enough full collections have been done to grow the old generation).
578 young_gen_action = grow_msg;
579 tenured_gen_action = no_change_msg;
580 }
581
582 // Minimum footprint
583 if (decrease_for_footprint() != 0) {
584 young_gen_action = shrink_msg;
585 tenured_gen_action = shrink_msg;
586 }
587
588 log_debug(gc, ergo)("UseAdaptiveSizePolicy actions to meet %s", action);
589 log_debug(gc, ergo)(" GC overhead (%%)");
590 log_debug(gc, ergo)(" Young generation: %7.2f\t %s",
591 100.0 * avg_minor_gc_cost()->average(), young_gen_action);
592 log_debug(gc, ergo)(" Tenured generation: %7.2f\t %s",
593 100.0 * avg_major_gc_cost()->average(), tenured_gen_action);
594 return true;
595 }
596
597 void AdaptiveSizePolicy::print_tenuring_threshold( uint new_tenuring_threshold_arg) const {
598 // Tenuring threshold
599 if (decrement_tenuring_threshold_for_survivor_limit()) {
600 log_debug(gc, ergo)("Tenuring threshold: (attempted to decrease to avoid survivor space overflow) = %u", new_tenuring_threshold_arg);
601 } else if (decrement_tenuring_threshold_for_gc_cost()) {
602 log_debug(gc, ergo)("Tenuring threshold: (attempted to decrease to balance GC costs) = %u", new_tenuring_threshold_arg);
603 } else if (increment_tenuring_threshold_for_gc_cost()) {
604 log_debug(gc, ergo)("Tenuring threshold: (attempted to increase to balance GC costs) = %u", new_tenuring_threshold_arg);
605 } else {
606 assert(!tenuring_threshold_change(), "(no change was attempted)");
607 }
608 }