1 /*
2 * Copyright (c) 2004, 2016, 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/workgroup.hpp"
30 #include "logging/log.hpp"
31 #include "runtime/timer.hpp"
32 #include "utilities/ostream.hpp"
33 elapsedTimer AdaptiveSizePolicy::_minor_timer;
34 elapsedTimer AdaptiveSizePolicy::_major_timer;
35 bool AdaptiveSizePolicy::_debug_perturbation = false;
36
37 // The throughput goal is implemented as
38 // _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
39 // gc_cost_ratio is the ratio
40 // application cost / gc cost
41 // For example a gc_cost_ratio of 4 translates into a
42 // throughput goal of .80
43
44 AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
45 size_t init_promo_size,
46 size_t init_survivor_size,
47 double gc_pause_goal_sec,
48 uint gc_cost_ratio) :
49 _eden_size(init_eden_size),
50 _promo_size(init_promo_size),
51 _survivor_size(init_survivor_size),
52 _gc_pause_goal_sec(gc_pause_goal_sec),
53 _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
54 _gc_overhead_limit_exceeded(false),
55 _print_gc_overhead_limit_would_be_exceeded(false),
56 _gc_overhead_limit_count(0),
57 _latest_minor_mutator_interval_seconds(0),
58 _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
59 _young_gen_change_for_minor_throughput(0),
60 _old_gen_change_for_major_throughput(0) {
61 assert(AdaptiveSizePolicyGCTimeLimitThreshold > 0,
62 "No opportunity to clear SoftReferences before GC overhead limit");
63 _avg_minor_pause =
64 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
65 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
66 _avg_minor_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
67 _avg_major_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
68
69 _avg_young_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
70 _avg_old_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
71 _avg_eden_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
72
73 _avg_survived = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
74 SurvivorPadding);
75 _avg_pretenured = new AdaptivePaddedNoZeroDevAverage(
76 AdaptiveSizePolicyWeight,
77 SurvivorPadding);
78
79 _minor_pause_old_estimator =
80 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
81 _minor_pause_young_estimator =
82 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
83 _minor_collection_estimator =
84 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
85 _major_collection_estimator =
86 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
87
88 // Start the timers
89 _minor_timer.start();
90
91 _young_gen_policy_is_ready = false;
92 }
93
94 // If the number of GC threads was set on the command line,
95 // use it.
96 // Else
97 // Calculate the number of GC threads based on the number of Java threads.
98 // Calculate the number of GC threads based on the size of the heap.
99 // Use the larger.
100
101 uint AdaptiveSizePolicy::calc_default_active_workers(uintx total_workers,
102 const uintx min_workers,
103 uintx active_workers,
104 uintx application_workers) {
105 // If the user has specifically set the number of
106 // GC threads, use them.
107
108 // If the user has turned off using a dynamic number of GC threads
109 // or the users has requested a specific number, set the active
110 // number of workers to all the workers.
111
112 uintx new_active_workers = total_workers;
113 uintx prev_active_workers = active_workers;
114 uintx active_workers_by_JT = 0;
115 uintx active_workers_by_heap_size = 0;
116
117 // Always use at least min_workers but use up to
118 // GCThreadsPerJavaThreads * application threads.
119 active_workers_by_JT =
120 MAX2((uintx) GCWorkersPerJavaThread * application_workers,
121 min_workers);
122
123 // Choose a number of GC threads based on the current size
124 // of the heap. This may be complicated because the size of
125 // the heap depends on factors such as the throughput goal.
126 // Still a large heap should be collected by more GC threads.
127 active_workers_by_heap_size =
128 MAX2((size_t) 2U, GC::gc()->heap()->capacity() / HeapSizePerGCThread);
129
130 uintx max_active_workers =
131 MAX2(active_workers_by_JT, active_workers_by_heap_size);
132
133 new_active_workers = MIN2(max_active_workers, (uintx) total_workers);
134
135 // Increase GC workers instantly but decrease them more
136 // slowly.
137 if (new_active_workers < prev_active_workers) {
138 new_active_workers =
139 MAX2(min_workers, (prev_active_workers + new_active_workers) / 2);
140 }
141
142 // Check once more that the number of workers is within the limits.
143 assert(min_workers <= total_workers, "Minimum workers not consistent with total workers");
144 assert(new_active_workers >= min_workers, "Minimum workers not observed");
145 assert(new_active_workers <= total_workers, "Total workers not observed");
146
147 if (ForceDynamicNumberOfGCThreads) {
148 // Assume this is debugging and jiggle the number of GC threads.
149 if (new_active_workers == prev_active_workers) {
150 if (new_active_workers < total_workers) {
151 new_active_workers++;
152 } else if (new_active_workers > min_workers) {
153 new_active_workers--;
154 }
155 }
156 if (new_active_workers == total_workers) {
157 if (_debug_perturbation) {
158 new_active_workers = min_workers;
159 }
160 _debug_perturbation = !_debug_perturbation;
161 }
162 assert((new_active_workers <= ParallelGCThreads) &&
163 (new_active_workers >= min_workers),
164 "Jiggled active workers too much");
165 }
166
167 log_trace(gc, task)("GCTaskManager::calc_default_active_workers() : "
168 "active_workers(): " UINTX_FORMAT " new_active_workers: " UINTX_FORMAT " "
169 "prev_active_workers: " UINTX_FORMAT "\n"
170 " active_workers_by_JT: " UINTX_FORMAT " active_workers_by_heap_size: " UINTX_FORMAT,
171 active_workers, new_active_workers, prev_active_workers,
172 active_workers_by_JT, active_workers_by_heap_size);
173 assert(new_active_workers > 0, "Always need at least 1");
174 return new_active_workers;
175 }
176
177 uint AdaptiveSizePolicy::calc_active_workers(uintx total_workers,
178 uintx active_workers,
179 uintx application_workers) {
180 // If the user has specifically set the number of
181 // GC threads, use them.
182
183 // If the user has turned off using a dynamic number of GC threads
184 // or the users has requested a specific number, set the active
185 // number of workers to all the workers.
186
187 uint new_active_workers;
188 if (!UseDynamicNumberOfGCThreads ||
189 (!FLAG_IS_DEFAULT(ParallelGCThreads) && !ForceDynamicNumberOfGCThreads)) {
190 new_active_workers = total_workers;
191 } else {
192 uintx min_workers = (total_workers == 1) ? 1 : 2;
193 new_active_workers = calc_default_active_workers(total_workers,
194 min_workers,
195 active_workers,
196 application_workers);
197 }
198 assert(new_active_workers > 0, "Always need at least 1");
199 return new_active_workers;
200 }
201
202 uint AdaptiveSizePolicy::calc_active_conc_workers(uintx total_workers,
203 uintx active_workers,
204 uintx application_workers) {
205 if (!UseDynamicNumberOfGCThreads ||
206 (!FLAG_IS_DEFAULT(ConcGCThreads) && !ForceDynamicNumberOfGCThreads)) {
207 return ConcGCThreads;
208 } else {
209 uint no_of_gc_threads = calc_default_active_workers(total_workers,
210 1, /* Minimum number of workers */
211 active_workers,
212 application_workers);
213 return no_of_gc_threads;
214 }
215 }
216
217 bool AdaptiveSizePolicy::tenuring_threshold_change() const {
218 return decrement_tenuring_threshold_for_gc_cost() ||
219 increment_tenuring_threshold_for_gc_cost() ||
220 decrement_tenuring_threshold_for_survivor_limit();
221 }
222
223 void AdaptiveSizePolicy::minor_collection_begin() {
224 // Update the interval time
225 _minor_timer.stop();
226 // Save most recent collection time
227 _latest_minor_mutator_interval_seconds = _minor_timer.seconds();
228 _minor_timer.reset();
229 _minor_timer.start();
230 }
231
232 void AdaptiveSizePolicy::update_minor_pause_young_estimator(
233 double minor_pause_in_ms) {
234 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
235 _minor_pause_young_estimator->update(eden_size_in_mbytes,
236 minor_pause_in_ms);
237 }
238
239 void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) {
240 // Update the pause time.
241 _minor_timer.stop();
242
243 if (!GCCause::is_user_requested_gc(gc_cause) ||
244 UseAdaptiveSizePolicyWithSystemGC) {
245 double minor_pause_in_seconds = _minor_timer.seconds();
246 double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS;
247
248 // Sample for performance counter
249 _avg_minor_pause->sample(minor_pause_in_seconds);
250
251 // Cost of collection (unit-less)
252 double collection_cost = 0.0;
253 if ((_latest_minor_mutator_interval_seconds > 0.0) &&
254 (minor_pause_in_seconds > 0.0)) {
255 double interval_in_seconds =
256 _latest_minor_mutator_interval_seconds + minor_pause_in_seconds;
257 collection_cost =
258 minor_pause_in_seconds / interval_in_seconds;
259 _avg_minor_gc_cost->sample(collection_cost);
260 // Sample for performance counter
261 _avg_minor_interval->sample(interval_in_seconds);
262 }
263
264 // The policy does not have enough data until at least some
265 // young collections have been done.
266 _young_gen_policy_is_ready =
267 (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold);
268
269 // Calculate variables used to estimate pause time vs. gen sizes
270 double eden_size_in_mbytes = ((double)_eden_size) / ((double)M);
271 update_minor_pause_young_estimator(minor_pause_in_ms);
272 update_minor_pause_old_estimator(minor_pause_in_ms);
273
274 log_trace(gc, ergo)("AdaptiveSizePolicy::minor_collection_end: minor gc cost: %f average: %f",
275 collection_cost, _avg_minor_gc_cost->average());
276 log_trace(gc, ergo)(" minor pause: %f minor period %f",
277 minor_pause_in_ms, _latest_minor_mutator_interval_seconds * MILLIUNITS);
278
279 // Calculate variable used to estimate collection cost vs. gen sizes
280 assert(collection_cost >= 0.0, "Expected to be non-negative");
281 _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost);
282 }
283
284 // Interval times use this timer to measure the mutator time.
285 // Reset the timer after the GC pause.
286 _minor_timer.reset();
287 _minor_timer.start();
288 }
289
290 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden, uint percent_change) {
291 size_t eden_heap_delta;
292 eden_heap_delta = cur_eden / 100 * percent_change;
293 return eden_heap_delta;
294 }
295
296 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) {
297 return eden_increment(cur_eden, YoungGenerationSizeIncrement);
298 }
299
300 size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
301 size_t eden_heap_delta = eden_increment(cur_eden) /
302 AdaptiveSizeDecrementScaleFactor;
303 return eden_heap_delta;
304 }
305
306 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo, uint percent_change) {
307 size_t promo_heap_delta;
308 promo_heap_delta = cur_promo / 100 * percent_change;
309 return promo_heap_delta;
310 }
311
312 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) {
313 return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
314 }
315
316 size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
317 size_t promo_heap_delta = promo_increment(cur_promo);
318 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
319 return promo_heap_delta;
320 }
321
322 double AdaptiveSizePolicy::time_since_major_gc() const {
323 _major_timer.stop();
324 double result = _major_timer.seconds();
325 _major_timer.start();
326 return result;
327 }
328
329 // Linear decay of major gc cost
330 double AdaptiveSizePolicy::decaying_major_gc_cost() const {
331 double major_interval = major_gc_interval_average_for_decay();
332 double major_gc_cost_average = major_gc_cost();
333 double decayed_major_gc_cost = major_gc_cost_average;
334 if(time_since_major_gc() > 0.0) {
335 decayed_major_gc_cost = major_gc_cost() *
336 (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval)
337 / time_since_major_gc();
338 }
339
340 // The decayed cost should always be smaller than the
341 // average cost but the vagaries of finite arithmetic could
342 // produce a larger value in decayed_major_gc_cost so protect
343 // against that.
344 return MIN2(major_gc_cost_average, decayed_major_gc_cost);
345 }
346
347 // Use a value of the major gc cost that has been decayed
348 // by the factor
349 //
350 // average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale /
351 // time-since-last-major-gc
352 //
353 // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale
354 // is less than time-since-last-major-gc.
355 //
356 // In cases where there are initial major gc's that
357 // are of a relatively high cost but no later major
358 // gc's, the total gc cost can remain high because
359 // the major gc cost remains unchanged (since there are no major
360 // gc's). In such a situation the value of the unchanging
361 // major gc cost can keep the mutator throughput below
362 // the goal when in fact the major gc cost is becoming diminishingly
363 // small. Use the decaying gc cost only to decide whether to
364 // adjust for throughput. Using it also to determine the adjustment
365 // to be made for throughput also seems reasonable but there is
366 // no test case to use to decide if it is the right thing to do
367 // don't do it yet.
368
369 double AdaptiveSizePolicy::decaying_gc_cost() const {
370 double decayed_major_gc_cost = major_gc_cost();
371 double avg_major_interval = major_gc_interval_average_for_decay();
372 if (UseAdaptiveSizeDecayMajorGCCost &&
373 (AdaptiveSizeMajorGCDecayTimeScale > 0) &&
374 (avg_major_interval > 0.00)) {
375 double time_since_last_major_gc = time_since_major_gc();
376
377 // Decay the major gc cost?
378 if (time_since_last_major_gc >
379 ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) {
380
381 // Decay using the time-since-last-major-gc
382 decayed_major_gc_cost = decaying_major_gc_cost();
383 log_trace(gc, ergo)("decaying_gc_cost: major interval average: %f time since last major gc: %f",
384 avg_major_interval, time_since_last_major_gc);
385 log_trace(gc, ergo)(" major gc cost: %f decayed major gc cost: %f",
386 major_gc_cost(), decayed_major_gc_cost);
387 }
388 }
389 double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
390 return result;
391 }
392
393
394 void AdaptiveSizePolicy::clear_generation_free_space_flags() {
395 set_change_young_gen_for_min_pauses(0);
396 set_change_old_gen_for_maj_pauses(0);
397
398 set_change_old_gen_for_throughput(0);
399 set_change_young_gen_for_throughput(0);
400 set_decrease_for_footprint(0);
401 set_decide_at_full_gc(0);
402 }
403
404 void AdaptiveSizePolicy::check_gc_overhead_limit(
405 size_t young_live,
406 size_t eden_live,
407 size_t max_old_gen_size,
408 size_t max_eden_size,
409 bool is_full_gc,
410 GCCause::Cause gc_cause,
411 CollectorPolicy* collector_policy) {
412
413 // Ignore explicit GC's. Exiting here does not set the flag and
414 // does not reset the count. Updating of the averages for system
415 // GC's is still controlled by UseAdaptiveSizePolicyWithSystemGC.
416 if (GCCause::is_user_requested_gc(gc_cause) ||
417 GCCause::is_serviceability_requested_gc(gc_cause)) {
418 return;
419 }
420 // eden_limit is the upper limit on the size of eden based on
421 // the maximum size of the young generation and the sizes
422 // of the survivor space.
423 // The question being asked is whether the gc costs are high
424 // and the space being recovered by a collection is low.
425 // free_in_young_gen is the free space in the young generation
426 // after a collection and promo_live is the free space in the old
427 // generation after a collection.
428 //
429 // Use the minimum of the current value of the live in the
430 // young gen or the average of the live in the young gen.
431 // If the current value drops quickly, that should be taken
432 // into account (i.e., don't trigger if the amount of free
433 // space has suddenly jumped up). If the current is much
434 // higher than the average, use the average since it represents
435 // the longer term behavior.
436 const size_t live_in_eden =
437 MIN2(eden_live, (size_t) avg_eden_live()->average());
438 const size_t free_in_eden = max_eden_size > live_in_eden ?
439 max_eden_size - live_in_eden : 0;
440 const size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
441 const size_t total_free_limit = free_in_old_gen + free_in_eden;
442 const size_t total_mem = max_old_gen_size + max_eden_size;
443 const double mem_free_limit = total_mem * (GCHeapFreeLimit/100.0);
444 const double mem_free_old_limit = max_old_gen_size * (GCHeapFreeLimit/100.0);
445 const double mem_free_eden_limit = max_eden_size * (GCHeapFreeLimit/100.0);
446 const double gc_cost_limit = GCTimeLimit/100.0;
447 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
448 // But don't force a promo size below the current promo size. Otherwise,
449 // the promo size will shrink for no good reason.
450 promo_limit = MAX2(promo_limit, _promo_size);
451
452
453 log_trace(gc, ergo)(
454 "PSAdaptiveSizePolicy::check_gc_overhead_limit:"
455 " promo_limit: " SIZE_FORMAT
456 " max_eden_size: " SIZE_FORMAT
457 " total_free_limit: " SIZE_FORMAT
458 " max_old_gen_size: " SIZE_FORMAT
459 " max_eden_size: " SIZE_FORMAT
460 " mem_free_limit: " SIZE_FORMAT,
461 promo_limit, max_eden_size, total_free_limit,
462 max_old_gen_size, max_eden_size,
463 (size_t) mem_free_limit);
464
465 bool print_gc_overhead_limit_would_be_exceeded = false;
466 if (is_full_gc) {
467 if (gc_cost() > gc_cost_limit &&
468 free_in_old_gen < (size_t) mem_free_old_limit &&
469 free_in_eden < (size_t) mem_free_eden_limit) {
470 // Collections, on average, are taking too much time, and
471 // gc_cost() > gc_cost_limit
472 // we have too little space available after a full gc.
473 // total_free_limit < mem_free_limit
474 // where
475 // total_free_limit is the free space available in
476 // both generations
477 // total_mem is the total space available for allocation
478 // in both generations (survivor spaces are not included
479 // just as they are not included in eden_limit).
480 // mem_free_limit is a fraction of total_mem judged to be an
481 // acceptable amount that is still unused.
482 // The heap can ask for the value of this variable when deciding
483 // whether to thrown an OutOfMemory error.
484 // Note that the gc time limit test only works for the collections
485 // of the young gen + tenured gen and not for collections of the
486 // permanent gen. That is because the calculation of the space
487 // freed by the collection is the free space in the young gen +
488 // tenured gen.
489 // At this point the GC overhead limit is being exceeded.
490 inc_gc_overhead_limit_count();
491 if (UseGCOverheadLimit) {
492 if (gc_overhead_limit_count() >=
493 AdaptiveSizePolicyGCTimeLimitThreshold){
494 // All conditions have been met for throwing an out-of-memory
495 set_gc_overhead_limit_exceeded(true);
496 // Avoid consecutive OOM due to the gc time limit by resetting
497 // the counter.
498 reset_gc_overhead_limit_count();
499 } else {
500 // The required consecutive collections which exceed the
501 // GC time limit may or may not have been reached. We
502 // are approaching that condition and so as not to
503 // throw an out-of-memory before all SoftRef's have been
504 // cleared, set _should_clear_all_soft_refs in CollectorPolicy.
505 // The clearing will be done on the next GC.
506 bool near_limit = gc_overhead_limit_near();
507 if (near_limit) {
508 collector_policy->set_should_clear_all_soft_refs(true);
509 log_trace(gc, ergo)("Nearing GC overhead limit, will be clearing all SoftReference");
510 }
511 }
512 }
513 // Set this even when the overhead limit will not
514 // cause an out-of-memory. Diagnostic message indicating
515 // that the overhead limit is being exceeded is sometimes
516 // printed.
517 print_gc_overhead_limit_would_be_exceeded = true;
518
519 } else {
520 // Did not exceed overhead limits
521 reset_gc_overhead_limit_count();
522 }
523 }
524
525 if (UseGCOverheadLimit) {
526 if (gc_overhead_limit_exceeded()) {
527 log_trace(gc, ergo)("GC is exceeding overhead limit of " UINTX_FORMAT "%%", GCTimeLimit);
528 reset_gc_overhead_limit_count();
529 } else if (print_gc_overhead_limit_would_be_exceeded) {
530 assert(gc_overhead_limit_count() > 0, "Should not be printing");
531 log_trace(gc, ergo)("GC would exceed overhead limit of " UINTX_FORMAT "%% %d consecutive time(s)",
532 GCTimeLimit, gc_overhead_limit_count());
533 }
534 }
535 }
536 // Printing
537
538 bool AdaptiveSizePolicy::print() const {
539 assert(UseAdaptiveSizePolicy, "UseAdaptiveSizePolicy need to be enabled.");
540
541 if (!log_is_enabled(Debug, gc, ergo)) {
542 return false;
543 }
544
545 // Print goal for which action is needed.
546 char* action = NULL;
547 bool change_for_pause = false;
548 if ((change_old_gen_for_maj_pauses() ==
549 decrease_old_gen_for_maj_pauses_true) ||
550 (change_young_gen_for_min_pauses() ==
551 decrease_young_gen_for_min_pauses_true)) {
552 action = (char*) " *** pause time goal ***";
553 change_for_pause = true;
554 } else if ((change_old_gen_for_throughput() ==
555 increase_old_gen_for_throughput_true) ||
556 (change_young_gen_for_throughput() ==
557 increase_young_gen_for_througput_true)) {
558 action = (char*) " *** throughput goal ***";
559 } else if (decrease_for_footprint()) {
560 action = (char*) " *** reduced footprint ***";
561 } else {
562 // No actions were taken. This can legitimately be the
563 // situation if not enough data has been gathered to make
564 // decisions.
565 return false;
566 }
567
568 // Pauses
569 // Currently the size of the old gen is only adjusted to
570 // change the major pause times.
571 char* young_gen_action = NULL;
572 char* tenured_gen_action = NULL;
573
574 char* shrink_msg = (char*) "(attempted to shrink)";
575 char* grow_msg = (char*) "(attempted to grow)";
576 char* no_change_msg = (char*) "(no change)";
577 if (change_young_gen_for_min_pauses() ==
578 decrease_young_gen_for_min_pauses_true) {
579 young_gen_action = shrink_msg;
580 } else if (change_for_pause) {
581 young_gen_action = no_change_msg;
582 }
583
584 if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) {
585 tenured_gen_action = shrink_msg;
586 } else if (change_for_pause) {
587 tenured_gen_action = no_change_msg;
588 }
589
590 // Throughput
591 if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) {
592 assert(change_young_gen_for_throughput() ==
593 increase_young_gen_for_througput_true,
594 "Both generations should be growing");
595 young_gen_action = grow_msg;
596 tenured_gen_action = grow_msg;
597 } else if (change_young_gen_for_throughput() ==
598 increase_young_gen_for_througput_true) {
599 // Only the young generation may grow at start up (before
600 // enough full collections have been done to grow the old generation).
601 young_gen_action = grow_msg;
602 tenured_gen_action = no_change_msg;
603 }
604
605 // Minimum footprint
606 if (decrease_for_footprint() != 0) {
607 young_gen_action = shrink_msg;
608 tenured_gen_action = shrink_msg;
609 }
610
611 log_debug(gc, ergo)("UseAdaptiveSizePolicy actions to meet %s", action);
612 log_debug(gc, ergo)(" GC overhead (%%)");
613 log_debug(gc, ergo)(" Young generation: %7.2f\t %s",
614 100.0 * avg_minor_gc_cost()->average(), young_gen_action);
615 log_debug(gc, ergo)(" Tenured generation: %7.2f\t %s",
616 100.0 * avg_major_gc_cost()->average(), tenured_gen_action);
617 return true;
618 }
619
620 void AdaptiveSizePolicy::print_tenuring_threshold( uint new_tenuring_threshold_arg) const {
621 // Tenuring threshold
622 if (decrement_tenuring_threshold_for_survivor_limit()) {
623 log_debug(gc, ergo)("Tenuring threshold: (attempted to decrease to avoid survivor space overflow) = %u", new_tenuring_threshold_arg);
624 } else if (decrement_tenuring_threshold_for_gc_cost()) {
625 log_debug(gc, ergo)("Tenuring threshold: (attempted to decrease to balance GC costs) = %u", new_tenuring_threshold_arg);
626 } else if (increment_tenuring_threshold_for_gc_cost()) {
627 log_debug(gc, ergo)("Tenuring threshold: (attempted to increase to balance GC costs) = %u", new_tenuring_threshold_arg);
628 } else {
629 assert(!tenuring_threshold_change(), "(no change was attempted)");
630 }
631 }
632
633 bool AdaptiveSizePolicyOutput::enabled() {
634 return UseParallelGC &&
635 UseAdaptiveSizePolicy &&
636 log_is_enabled(Debug, gc, ergo);
637 }
638
639 void AdaptiveSizePolicyOutput::print() {
640 if (enabled()) {
641 GC::gc()->heap()->size_policy()->print();
642 }
643 }
644
645 void AdaptiveSizePolicyOutput::print(AdaptiveSizePolicy* size_policy, uint count) {
646 bool do_print =
647 enabled() &&
648 (AdaptiveSizePolicyOutputInterval > 0) &&
649 (count % AdaptiveSizePolicyOutputInterval) == 0;
650
651 if (do_print) {
652 size_policy->print();
653 }
654 }