Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp @ 6735:aed758eda82a
7195833: NPG: Rename instanceClassLoaderKlass, instanceRefKlass and instanceMirrorKlass
Summary: Simple renaming to be consistent with instanceKlass->InstanceKlass renaming
Reviewed-by: stefank, jmasa
author | coleenp |
---|---|
date | Fri, 07 Sep 2012 12:04:16 -0400 |
parents | da91efe96a93 |
children | 22b8d3d181d9 |
rev | line source |
---|---|
0 | 1 /* |
6725
da91efe96a93
6964458: Reimplement class meta-data storage to use native memory
coleenp
parents:
1972
diff
changeset
|
2 * Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
1552
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1387
diff
changeset
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1387
diff
changeset
|
20 * or visit www.oracle.com if you need additional information or have any |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1387
diff
changeset
|
21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "gc_implementation/parallelScavenge/generationSizer.hpp" | |
27 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp" | |
28 #include "gc_implementation/parallelScavenge/psGCAdaptivePolicyCounters.hpp" | |
29 #include "gc_implementation/parallelScavenge/psScavenge.hpp" | |
30 #include "gc_implementation/shared/gcPolicyCounters.hpp" | |
31 #include "gc_interface/gcCause.hpp" | |
32 #include "memory/collectorPolicy.hpp" | |
33 #include "runtime/timer.hpp" | |
34 #include "utilities/top.hpp" | |
0 | 35 |
36 #include <math.h> | |
37 | |
38 PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size, | |
39 size_t init_promo_size, | |
40 size_t init_survivor_size, | |
41 size_t intra_generation_alignment, | |
42 double gc_pause_goal_sec, | |
43 double gc_minor_pause_goal_sec, | |
44 uint gc_cost_ratio) : | |
45 AdaptiveSizePolicy(init_eden_size, | |
46 init_promo_size, | |
47 init_survivor_size, | |
48 gc_pause_goal_sec, | |
49 gc_cost_ratio), | |
50 _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin/ | |
51 100.0), | |
52 _intra_generation_alignment(intra_generation_alignment), | |
53 _live_at_last_full_gc(init_promo_size), | |
54 _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec), | |
55 _latest_major_mutator_interval_seconds(0), | |
56 _young_gen_change_for_major_pause_count(0) | |
57 { | |
58 // Sizing policy statistics | |
59 _avg_major_pause = | |
60 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding); | |
61 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight); | |
62 _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight); | |
63 | |
64 _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight); | |
65 _major_pause_old_estimator = | |
66 new LinearLeastSquareFit(AdaptiveSizePolicyWeight); | |
67 _major_pause_young_estimator = | |
68 new LinearLeastSquareFit(AdaptiveSizePolicyWeight); | |
69 _major_collection_estimator = | |
70 new LinearLeastSquareFit(AdaptiveSizePolicyWeight); | |
71 | |
72 _young_gen_size_increment_supplement = YoungGenerationSizeSupplement; | |
73 _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement; | |
74 | |
75 // Start the timers | |
76 _major_timer.start(); | |
77 | |
78 _old_gen_policy_is_ready = false; | |
79 } | |
80 | |
81 void PSAdaptiveSizePolicy::major_collection_begin() { | |
82 // Update the interval time | |
83 _major_timer.stop(); | |
84 // Save most recent collection time | |
85 _latest_major_mutator_interval_seconds = _major_timer.seconds(); | |
86 _major_timer.reset(); | |
87 _major_timer.start(); | |
88 } | |
89 | |
90 void PSAdaptiveSizePolicy::update_minor_pause_old_estimator( | |
91 double minor_pause_in_ms) { | |
92 double promo_size_in_mbytes = ((double)_promo_size)/((double)M); | |
93 _minor_pause_old_estimator->update(promo_size_in_mbytes, | |
94 minor_pause_in_ms); | |
95 } | |
96 | |
97 void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live, | |
98 GCCause::Cause gc_cause) { | |
99 // Update the pause time. | |
100 _major_timer.stop(); | |
101 | |
102 if (gc_cause != GCCause::_java_lang_system_gc || | |
103 UseAdaptiveSizePolicyWithSystemGC) { | |
104 double major_pause_in_seconds = _major_timer.seconds(); | |
105 double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS; | |
106 | |
107 // Sample for performance counter | |
108 _avg_major_pause->sample(major_pause_in_seconds); | |
109 | |
110 // Cost of collection (unit-less) | |
111 double collection_cost = 0.0; | |
112 if ((_latest_major_mutator_interval_seconds > 0.0) && | |
113 (major_pause_in_seconds > 0.0)) { | |
114 double interval_in_seconds = | |
115 _latest_major_mutator_interval_seconds + major_pause_in_seconds; | |
116 collection_cost = | |
117 major_pause_in_seconds / interval_in_seconds; | |
118 avg_major_gc_cost()->sample(collection_cost); | |
119 | |
120 // Sample for performance counter | |
121 _avg_major_interval->sample(interval_in_seconds); | |
122 } | |
123 | |
124 // Calculate variables used to estimate pause time vs. gen sizes | |
125 double eden_size_in_mbytes = ((double)_eden_size)/((double)M); | |
126 double promo_size_in_mbytes = ((double)_promo_size)/((double)M); | |
127 _major_pause_old_estimator->update(promo_size_in_mbytes, | |
128 major_pause_in_ms); | |
129 _major_pause_young_estimator->update(eden_size_in_mbytes, | |
130 major_pause_in_ms); | |
131 | |
132 if (PrintAdaptiveSizePolicy && Verbose) { | |
133 gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: " | |
134 "major gc cost: %f average: %f", collection_cost, | |
135 avg_major_gc_cost()->average()); | |
136 gclog_or_tty->print_cr(" major pause: %f major period %f", | |
137 major_pause_in_ms, | |
138 _latest_major_mutator_interval_seconds * MILLIUNITS); | |
139 } | |
140 | |
141 // Calculate variable used to estimate collection cost vs. gen sizes | |
142 assert(collection_cost >= 0.0, "Expected to be non-negative"); | |
143 _major_collection_estimator->update(promo_size_in_mbytes, | |
144 collection_cost); | |
145 } | |
146 | |
147 // Update the amount live at the end of a full GC | |
148 _live_at_last_full_gc = amount_live; | |
149 | |
150 // The policy does not have enough data until at least some major collections | |
151 // have been done. | |
152 if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) { | |
153 _old_gen_policy_is_ready = true; | |
154 } | |
155 | |
156 // Interval times use this timer to measure the interval that | |
157 // the mutator runs. Reset after the GC pause has been measured. | |
158 _major_timer.reset(); | |
159 _major_timer.start(); | |
160 } | |
161 | |
162 // If the remaining free space in the old generation is less that | |
163 // that expected to be needed by the next collection, do a full | |
164 // collection now. | |
165 bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) { | |
166 | |
167 // A similar test is done in the scavenge's should_attempt_scavenge(). If | |
168 // this is changed, decide if that test should also be changed. | |
169 bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes; | |
170 if (PrintGCDetails && Verbose) { | |
171 if (result) { | |
172 gclog_or_tty->print(" full after scavenge: "); | |
173 } else { | |
174 gclog_or_tty->print(" no full after scavenge: "); | |
175 } | |
176 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT | |
177 " padded_average_promoted " SIZE_FORMAT | |
178 " free in old gen " SIZE_FORMAT, | |
179 (size_t) average_promoted_in_bytes(), | |
180 (size_t) padded_average_promoted_in_bytes(), | |
181 old_free_in_bytes); | |
182 } | |
183 return result; | |
184 } | |
185 | |
186 void PSAdaptiveSizePolicy::clear_generation_free_space_flags() { | |
187 | |
188 AdaptiveSizePolicy::clear_generation_free_space_flags(); | |
189 | |
190 set_change_old_gen_for_min_pauses(0); | |
191 | |
192 set_change_young_gen_for_maj_pauses(0); | |
193 } | |
194 | |
195 // If this is not a full GC, only test and modify the young generation. | |
196 | |
1387
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
197 void PSAdaptiveSizePolicy::compute_generation_free_space( |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
198 size_t young_live, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
199 size_t eden_live, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
200 size_t old_live, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
201 size_t cur_eden, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
202 size_t max_old_gen_size, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
203 size_t max_eden_size, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
204 bool is_full_gc, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
205 GCCause::Cause gc_cause, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
206 CollectorPolicy* collector_policy) { |
0 | 207 |
208 // Update statistics | |
209 // Time statistics are updated as we go, update footprint stats here | |
6725
da91efe96a93
6964458: Reimplement class meta-data storage to use native memory
coleenp
parents:
1972
diff
changeset
|
210 _avg_base_footprint->sample(BaseFootPrintEstimate); |
0 | 211 avg_young_live()->sample(young_live); |
212 avg_eden_live()->sample(eden_live); | |
213 if (is_full_gc) { | |
214 // old_live is only accurate after a full gc | |
215 avg_old_live()->sample(old_live); | |
216 } | |
217 | |
218 // This code used to return if the policy was not ready , i.e., | |
219 // policy_is_ready() returning false. The intent was that | |
220 // decisions below needed major collection times and so could | |
221 // not be made before two major collections. A consequence was | |
222 // adjustments to the young generation were not done until after | |
223 // two major collections even if the minor collections times | |
224 // exceeded the requested goals. Now let the young generation | |
225 // adjust for the minor collection times. Major collection times | |
226 // will be zero for the first collection and will naturally be | |
227 // ignored. Tenured generation adjustments are only made at the | |
228 // full collections so until the second major collection has | |
229 // been reached, no tenured generation adjustments will be made. | |
230 | |
231 // Until we know better, desired promotion size uses the last calculation | |
232 size_t desired_promo_size = _promo_size; | |
233 | |
234 // Start eden at the current value. The desired value that is stored | |
235 // in _eden_size is not bounded by constraints of the heap and can | |
236 // run away. | |
237 // | |
238 // As expected setting desired_eden_size to the current | |
239 // value of desired_eden_size as a starting point | |
240 // caused desired_eden_size to grow way too large and caused | |
241 // an overflow down stream. It may have improved performance in | |
242 // some case but is dangerous. | |
243 size_t desired_eden_size = cur_eden; | |
244 | |
245 #ifdef ASSERT | |
246 size_t original_promo_size = desired_promo_size; | |
247 size_t original_eden_size = desired_eden_size; | |
248 #endif | |
249 | |
250 // Cache some values. There's a bit of work getting these, so | |
251 // we might save a little time. | |
252 const double major_cost = major_gc_cost(); | |
253 const double minor_cost = minor_gc_cost(); | |
254 | |
255 // Used for diagnostics | |
256 clear_generation_free_space_flags(); | |
257 | |
258 // Limits on our growth | |
259 size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average()); | |
260 | |
261 // This method sets the desired eden size. That plus the | |
262 // desired survivor space sizes sets the desired young generation | |
263 // size. This methods does not know what the desired survivor | |
264 // size is but expects that other policy will attempt to make | |
265 // the survivor sizes compatible with the live data in the | |
266 // young generation. This limit is an estimate of the space left | |
267 // in the young generation after the survivor spaces have been | |
268 // subtracted out. | |
269 size_t eden_limit = max_eden_size; | |
270 | |
271 // But don't force a promo size below the current promo size. Otherwise, | |
272 // the promo size will shrink for no good reason. | |
273 promo_limit = MAX2(promo_limit, _promo_size); | |
274 | |
275 const double gc_cost_limit = GCTimeLimit/100.0; | |
276 | |
277 // Which way should we go? | |
278 // if pause requirement is not met | |
279 // adjust size of any generation with average paus exceeding | |
280 // the pause limit. Adjust one pause at a time (the larger) | |
281 // and only make adjustments for the major pause at full collections. | |
282 // else if throughput requirement not met | |
283 // adjust the size of the generation with larger gc time. Only | |
284 // adjust one generation at a time. | |
285 // else | |
286 // adjust down the total heap size. Adjust down the larger of the | |
287 // generations. | |
288 | |
289 // Add some checks for a threshhold for a change. For example, | |
290 // a change less than the necessary alignment is probably not worth | |
291 // attempting. | |
292 | |
293 | |
294 if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) || | |
295 (_avg_major_pause->padded_average() > gc_pause_goal_sec())) { | |
296 // | |
297 // Check pauses | |
298 // | |
299 // Make changes only to affect one of the pauses (the larger) | |
300 // at a time. | |
301 adjust_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size); | |
302 | |
303 } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) { | |
304 // Adjust only for the minor pause time goal | |
305 adjust_for_minor_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size); | |
306 | |
307 } else if(adjusted_mutator_cost() < _throughput_goal) { | |
308 // This branch used to require that (mutator_cost() > 0.0 in 1.4.2. | |
309 // This sometimes resulted in skipping to the minimize footprint | |
310 // code. Change this to try and reduce GC time if mutator time is | |
311 // negative for whatever reason. Or for future consideration, | |
312 // bail out of the code if mutator time is negative. | |
313 // | |
314 // Throughput | |
315 // | |
316 assert(major_cost >= 0.0, "major cost is < 0.0"); | |
317 assert(minor_cost >= 0.0, "minor cost is < 0.0"); | |
318 // Try to reduce the GC times. | |
319 adjust_for_throughput(is_full_gc, &desired_promo_size, &desired_eden_size); | |
320 | |
321 } else { | |
322 | |
323 // Be conservative about reducing the footprint. | |
324 // Do a minimum number of major collections first. | |
325 // Have reasonable averages for major and minor collections costs. | |
326 if (UseAdaptiveSizePolicyFootprintGoal && | |
327 young_gen_policy_is_ready() && | |
328 avg_major_gc_cost()->average() >= 0.0 && | |
329 avg_minor_gc_cost()->average() >= 0.0) { | |
330 size_t desired_sum = desired_eden_size + desired_promo_size; | |
331 desired_eden_size = adjust_eden_for_footprint(desired_eden_size, | |
332 desired_sum); | |
333 if (is_full_gc) { | |
334 set_decide_at_full_gc(decide_at_full_gc_true); | |
335 desired_promo_size = adjust_promo_for_footprint(desired_promo_size, | |
336 desired_sum); | |
337 } | |
338 } | |
339 } | |
340 | |
341 // Note we make the same tests as in the code block below; the code | |
342 // seems a little easier to read with the printing in another block. | |
343 if (PrintAdaptiveSizePolicy) { | |
344 if (desired_promo_size > promo_limit) { | |
345 // "free_in_old_gen" was the original value for used for promo_limit | |
346 size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average()); | |
347 gclog_or_tty->print_cr( | |
348 "PSAdaptiveSizePolicy::compute_generation_free_space limits:" | |
349 " desired_promo_size: " SIZE_FORMAT | |
350 " promo_limit: " SIZE_FORMAT | |
351 " free_in_old_gen: " SIZE_FORMAT | |
352 " max_old_gen_size: " SIZE_FORMAT | |
353 " avg_old_live: " SIZE_FORMAT, | |
354 desired_promo_size, promo_limit, free_in_old_gen, | |
355 max_old_gen_size, (size_t) avg_old_live()->average()); | |
356 } | |
357 if (desired_eden_size > eden_limit) { | |
358 gclog_or_tty->print_cr( | |
359 "AdaptiveSizePolicy::compute_generation_free_space limits:" | |
360 " desired_eden_size: " SIZE_FORMAT | |
361 " old_eden_size: " SIZE_FORMAT | |
362 " eden_limit: " SIZE_FORMAT | |
363 " cur_eden: " SIZE_FORMAT | |
364 " max_eden_size: " SIZE_FORMAT | |
365 " avg_young_live: " SIZE_FORMAT, | |
366 desired_eden_size, _eden_size, eden_limit, cur_eden, | |
367 max_eden_size, (size_t)avg_young_live()->average()); | |
368 } | |
369 if (gc_cost() > gc_cost_limit) { | |
370 gclog_or_tty->print_cr( | |
371 "AdaptiveSizePolicy::compute_generation_free_space: gc time limit" | |
372 " gc_cost: %f " | |
373 " GCTimeLimit: %d", | |
374 gc_cost(), GCTimeLimit); | |
375 } | |
376 } | |
377 | |
378 // Align everything and make a final limit check | |
379 const size_t alignment = _intra_generation_alignment; | |
380 desired_eden_size = align_size_up(desired_eden_size, alignment); | |
381 desired_eden_size = MAX2(desired_eden_size, alignment); | |
382 desired_promo_size = align_size_up(desired_promo_size, alignment); | |
383 desired_promo_size = MAX2(desired_promo_size, alignment); | |
384 | |
385 eden_limit = align_size_down(eden_limit, alignment); | |
386 promo_limit = align_size_down(promo_limit, alignment); | |
387 | |
388 // Is too much time being spent in GC? | |
389 // Is the heap trying to grow beyond it's limits? | |
390 | |
1387
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
391 const size_t free_in_old_gen = |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
392 (size_t)(max_old_gen_size - avg_old_live()->average()); |
0 | 393 if (desired_promo_size > free_in_old_gen && desired_eden_size > eden_limit) { |
1387
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
394 check_gc_overhead_limit(young_live, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
395 eden_live, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
396 max_old_gen_size, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
397 max_eden_size, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
398 is_full_gc, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
399 gc_cause, |
0bfd3fb24150
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
jmasa
parents:
0
diff
changeset
|
400 collector_policy); |
0 | 401 } |
402 | |
403 | |
404 // And one last limit check, now that we've aligned things. | |
405 if (desired_eden_size > eden_limit) { | |
406 // If the policy says to get a larger eden but | |
407 // is hitting the limit, don't decrease eden. | |
408 // This can lead to a general drifting down of the | |
409 // eden size. Let the tenuring calculation push more | |
410 // into the old gen. | |
411 desired_eden_size = MAX2(eden_limit, cur_eden); | |
412 } | |
413 desired_promo_size = MIN2(desired_promo_size, promo_limit); | |
414 | |
415 | |
416 if (PrintAdaptiveSizePolicy) { | |
417 // Timing stats | |
418 gclog_or_tty->print( | |
419 "PSAdaptiveSizePolicy::compute_generation_free_space: costs" | |
420 " minor_time: %f" | |
421 " major_cost: %f" | |
422 " mutator_cost: %f" | |
423 " throughput_goal: %f", | |
424 minor_gc_cost(), major_gc_cost(), mutator_cost(), | |
425 _throughput_goal); | |
426 | |
427 // We give more details if Verbose is set | |
428 if (Verbose) { | |
429 gclog_or_tty->print( " minor_pause: %f" | |
430 " major_pause: %f" | |
431 " minor_interval: %f" | |
432 " major_interval: %f" | |
433 " pause_goal: %f", | |
434 _avg_minor_pause->padded_average(), | |
435 _avg_major_pause->padded_average(), | |
436 _avg_minor_interval->average(), | |
437 _avg_major_interval->average(), | |
438 gc_pause_goal_sec()); | |
439 } | |
440 | |
441 // Footprint stats | |
442 gclog_or_tty->print( " live_space: " SIZE_FORMAT | |
443 " free_space: " SIZE_FORMAT, | |
444 live_space(), free_space()); | |
445 // More detail | |
446 if (Verbose) { | |
447 gclog_or_tty->print( " base_footprint: " SIZE_FORMAT | |
448 " avg_young_live: " SIZE_FORMAT | |
449 " avg_old_live: " SIZE_FORMAT, | |
450 (size_t)_avg_base_footprint->average(), | |
451 (size_t)avg_young_live()->average(), | |
452 (size_t)avg_old_live()->average()); | |
453 } | |
454 | |
455 // And finally, our old and new sizes. | |
456 gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT | |
457 " old_eden_size: " SIZE_FORMAT | |
458 " desired_promo_size: " SIZE_FORMAT | |
459 " desired_eden_size: " SIZE_FORMAT, | |
460 _promo_size, _eden_size, | |
461 desired_promo_size, desired_eden_size); | |
462 gclog_or_tty->cr(); | |
463 } | |
464 | |
465 decay_supplemental_growth(is_full_gc); | |
466 | |
467 set_promo_size(desired_promo_size); | |
468 set_eden_size(desired_eden_size); | |
469 }; | |
470 | |
471 void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) { | |
472 // Decay the supplemental increment? Decay the supplement growth | |
473 // factor even if it is not used. It is only meant to give a boost | |
474 // to the initial growth and if it is not used, then it was not | |
475 // needed. | |
476 if (is_full_gc) { | |
477 // Don't wait for the threshold value for the major collections. If | |
478 // here, the supplemental growth term was used and should decay. | |
479 if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay) | |
480 == 0) { | |
481 _old_gen_size_increment_supplement = | |
482 _old_gen_size_increment_supplement >> 1; | |
483 } | |
484 } else { | |
485 if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) && | |
486 (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) { | |
487 _young_gen_size_increment_supplement = | |
488 _young_gen_size_increment_supplement >> 1; | |
489 } | |
490 } | |
491 } | |
492 | |
493 void PSAdaptiveSizePolicy::adjust_for_minor_pause_time(bool is_full_gc, | |
494 size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) { | |
495 | |
496 // Adjust the young generation size to reduce pause time of | |
497 // of collections. | |
498 // | |
499 // The AdaptiveSizePolicyInitializingSteps test is not used | |
500 // here. It has not seemed to be needed but perhaps should | |
501 // be added for consistency. | |
502 if (minor_pause_young_estimator()->decrement_will_decrease()) { | |
503 // reduce eden size | |
504 set_change_young_gen_for_min_pauses( | |
505 decrease_young_gen_for_min_pauses_true); | |
506 *desired_eden_size_ptr = *desired_eden_size_ptr - | |
507 eden_decrement_aligned_down(*desired_eden_size_ptr); | |
508 } else { | |
509 // EXPERIMENTAL ADJUSTMENT | |
510 // Only record that the estimator indicated such an action. | |
511 // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta; | |
512 set_change_young_gen_for_min_pauses( | |
513 increase_young_gen_for_min_pauses_true); | |
514 } | |
515 if (PSAdjustTenuredGenForMinorPause) { | |
516 // If the desired eden size is as small as it will get, | |
517 // try to adjust the old gen size. | |
518 if (*desired_eden_size_ptr <= _intra_generation_alignment) { | |
519 // Vary the old gen size to reduce the young gen pause. This | |
520 // may not be a good idea. This is just a test. | |
521 if (minor_pause_old_estimator()->decrement_will_decrease()) { | |
522 set_change_old_gen_for_min_pauses( | |
523 decrease_old_gen_for_min_pauses_true); | |
524 *desired_promo_size_ptr = | |
525 _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr); | |
526 } else { | |
527 set_change_old_gen_for_min_pauses( | |
528 increase_old_gen_for_min_pauses_true); | |
529 size_t promo_heap_delta = | |
530 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr); | |
531 if ((*desired_promo_size_ptr + promo_heap_delta) > | |
532 *desired_promo_size_ptr) { | |
533 *desired_promo_size_ptr = | |
534 _promo_size + promo_heap_delta; | |
535 } | |
536 } | |
537 } | |
538 } | |
539 } | |
540 | |
541 void PSAdaptiveSizePolicy::adjust_for_pause_time(bool is_full_gc, | |
542 size_t* desired_promo_size_ptr, | |
543 size_t* desired_eden_size_ptr) { | |
544 | |
545 size_t promo_heap_delta = 0; | |
546 size_t eden_heap_delta = 0; | |
547 // Add some checks for a threshhold for a change. For example, | |
548 // a change less than the required alignment is probably not worth | |
549 // attempting. | |
550 if (is_full_gc) { | |
551 set_decide_at_full_gc(decide_at_full_gc_true); | |
552 } | |
553 | |
554 if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) { | |
555 adjust_for_minor_pause_time(is_full_gc, | |
556 desired_promo_size_ptr, | |
557 desired_eden_size_ptr); | |
558 // major pause adjustments | |
559 } else if (is_full_gc) { | |
560 // Adjust for the major pause time only at full gc's because the | |
561 // affects of a change can only be seen at full gc's. | |
562 | |
563 // Reduce old generation size to reduce pause? | |
564 if (major_pause_old_estimator()->decrement_will_decrease()) { | |
565 // reduce old generation size | |
566 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true); | |
567 promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr); | |
568 *desired_promo_size_ptr = _promo_size - promo_heap_delta; | |
569 } else { | |
570 // EXPERIMENTAL ADJUSTMENT | |
571 // Only record that the estimator indicated such an action. | |
572 // *desired_promo_size_ptr = _promo_size + | |
573 // promo_increment_aligned_up(*desired_promo_size_ptr); | |
574 set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true); | |
575 } | |
576 if (PSAdjustYoungGenForMajorPause) { | |
577 // If the promo size is at the minimum (i.e., the old gen | |
578 // size will not actually decrease), consider changing the | |
579 // young gen size. | |
580 if (*desired_promo_size_ptr < _intra_generation_alignment) { | |
581 // If increasing the young generation will decrease the old gen | |
582 // pause, do it. | |
583 // During startup there is noise in the statistics for deciding | |
584 // on whether to increase or decrease the young gen size. For | |
585 // some number of iterations, just try to increase the young | |
586 // gen size if the major pause is too long to try and establish | |
587 // good statistics for later decisions. | |
588 if (major_pause_young_estimator()->increment_will_decrease() || | |
589 (_young_gen_change_for_major_pause_count | |
590 <= AdaptiveSizePolicyInitializingSteps)) { | |
591 set_change_young_gen_for_maj_pauses( | |
592 increase_young_gen_for_maj_pauses_true); | |
593 eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr); | |
594 *desired_eden_size_ptr = _eden_size + eden_heap_delta; | |
595 _young_gen_change_for_major_pause_count++; | |
596 } else { | |
597 // Record that decreasing the young gen size would decrease | |
598 // the major pause | |
599 set_change_young_gen_for_maj_pauses( | |
600 decrease_young_gen_for_maj_pauses_true); | |
601 eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr); | |
602 *desired_eden_size_ptr = _eden_size - eden_heap_delta; | |
603 } | |
604 } | |
605 } | |
606 } | |
607 | |
608 if (PrintAdaptiveSizePolicy && Verbose) { | |
609 gclog_or_tty->print_cr( | |
610 "AdaptiveSizePolicy::compute_generation_free_space " | |
611 "adjusting gen sizes for major pause (avg %f goal %f). " | |
612 "desired_promo_size " SIZE_FORMAT "desired_eden_size " | |
613 SIZE_FORMAT | |
614 " promo delta " SIZE_FORMAT " eden delta " SIZE_FORMAT, | |
615 _avg_major_pause->average(), gc_pause_goal_sec(), | |
616 *desired_promo_size_ptr, *desired_eden_size_ptr, | |
617 promo_heap_delta, eden_heap_delta); | |
618 } | |
619 } | |
620 | |
621 void PSAdaptiveSizePolicy::adjust_for_throughput(bool is_full_gc, | |
622 size_t* desired_promo_size_ptr, | |
623 size_t* desired_eden_size_ptr) { | |
624 | |
625 // Add some checks for a threshhold for a change. For example, | |
626 // a change less than the required alignment is probably not worth | |
627 // attempting. | |
628 if (is_full_gc) { | |
629 set_decide_at_full_gc(decide_at_full_gc_true); | |
630 } | |
631 | |
632 if ((gc_cost() + mutator_cost()) == 0.0) { | |
633 return; | |
634 } | |
635 | |
636 if (PrintAdaptiveSizePolicy && Verbose) { | |
637 gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_for_throughput(" | |
638 "is_full: %d, promo: " SIZE_FORMAT ", cur_eden: " SIZE_FORMAT "): ", | |
639 is_full_gc, *desired_promo_size_ptr, *desired_eden_size_ptr); | |
640 gclog_or_tty->print_cr("mutator_cost %f major_gc_cost %f " | |
641 "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost()); | |
642 } | |
643 | |
644 // Tenured generation | |
645 if (is_full_gc) { | |
646 | |
647 // Calculate the change to use for the tenured gen. | |
648 size_t scaled_promo_heap_delta = 0; | |
649 // Can the increment to the generation be scaled? | |
650 if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) { | |
651 size_t promo_heap_delta = | |
652 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr); | |
653 double scale_by_ratio = major_gc_cost() / gc_cost(); | |
654 scaled_promo_heap_delta = | |
655 (size_t) (scale_by_ratio * (double) promo_heap_delta); | |
656 if (PrintAdaptiveSizePolicy && Verbose) { | |
657 gclog_or_tty->print_cr( | |
658 "Scaled tenured increment: " SIZE_FORMAT " by %f down to " | |
659 SIZE_FORMAT, | |
660 promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta); | |
661 } | |
662 } else if (major_gc_cost() >= 0.0) { | |
663 // Scaling is not going to work. If the major gc time is the | |
664 // larger, give it a full increment. | |
665 if (major_gc_cost() >= minor_gc_cost()) { | |
666 scaled_promo_heap_delta = | |
667 promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr); | |
668 } | |
669 } else { | |
670 // Don't expect to get here but it's ok if it does | |
671 // in the product build since the delta will be 0 | |
672 // and nothing will change. | |
673 assert(false, "Unexpected value for gc costs"); | |
674 } | |
675 | |
676 switch (AdaptiveSizeThroughPutPolicy) { | |
677 case 1: | |
678 // Early in the run the statistics might not be good. Until | |
679 // a specific number of collections have been, use the heuristic | |
680 // that a larger generation size means lower collection costs. | |
681 if (major_collection_estimator()->increment_will_decrease() || | |
682 (_old_gen_change_for_major_throughput | |
683 <= AdaptiveSizePolicyInitializingSteps)) { | |
684 // Increase tenured generation size to reduce major collection cost | |
685 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) > | |
686 *desired_promo_size_ptr) { | |
687 *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta; | |
688 } | |
689 set_change_old_gen_for_throughput( | |
690 increase_old_gen_for_throughput_true); | |
691 _old_gen_change_for_major_throughput++; | |
692 } else { | |
693 // EXPERIMENTAL ADJUSTMENT | |
694 // Record that decreasing the old gen size would decrease | |
695 // the major collection cost but don't do it. | |
696 // *desired_promo_size_ptr = _promo_size - | |
697 // promo_decrement_aligned_down(*desired_promo_size_ptr); | |
698 set_change_old_gen_for_throughput( | |
699 decrease_old_gen_for_throughput_true); | |
700 } | |
701 | |
702 break; | |
703 default: | |
704 // Simplest strategy | |
705 if ((*desired_promo_size_ptr + scaled_promo_heap_delta) > | |
706 *desired_promo_size_ptr) { | |
707 *desired_promo_size_ptr = *desired_promo_size_ptr + | |
708 scaled_promo_heap_delta; | |
709 } | |
710 set_change_old_gen_for_throughput( | |
711 increase_old_gen_for_throughput_true); | |
712 _old_gen_change_for_major_throughput++; | |
713 } | |
714 | |
715 if (PrintAdaptiveSizePolicy && Verbose) { | |
716 gclog_or_tty->print_cr( | |
717 "adjusting tenured gen for throughput (avg %f goal %f). " | |
718 "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT , | |
719 mutator_cost(), _throughput_goal, | |
720 *desired_promo_size_ptr, scaled_promo_heap_delta); | |
721 } | |
722 } | |
723 | |
724 // Young generation | |
725 size_t scaled_eden_heap_delta = 0; | |
726 // Can the increment to the generation be scaled? | |
727 if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) { | |
728 size_t eden_heap_delta = | |
729 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr); | |
730 double scale_by_ratio = minor_gc_cost() / gc_cost(); | |
731 assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong"); | |
732 scaled_eden_heap_delta = | |
733 (size_t) (scale_by_ratio * (double) eden_heap_delta); | |
734 if (PrintAdaptiveSizePolicy && Verbose) { | |
735 gclog_or_tty->print_cr( | |
736 "Scaled eden increment: " SIZE_FORMAT " by %f down to " | |
737 SIZE_FORMAT, | |
738 eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta); | |
739 } | |
740 } else if (minor_gc_cost() >= 0.0) { | |
741 // Scaling is not going to work. If the minor gc time is the | |
742 // larger, give it a full increment. | |
743 if (minor_gc_cost() > major_gc_cost()) { | |
744 scaled_eden_heap_delta = | |
745 eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr); | |
746 } | |
747 } else { | |
748 // Don't expect to get here but it's ok if it does | |
749 // in the product build since the delta will be 0 | |
750 // and nothing will change. | |
751 assert(false, "Unexpected value for gc costs"); | |
752 } | |
753 | |
754 // Use a heuristic for some number of collections to give | |
755 // the averages time to settle down. | |
756 switch (AdaptiveSizeThroughPutPolicy) { | |
757 case 1: | |
758 if (minor_collection_estimator()->increment_will_decrease() || | |
759 (_young_gen_change_for_minor_throughput | |
760 <= AdaptiveSizePolicyInitializingSteps)) { | |
761 // Expand young generation size to reduce frequency of | |
762 // of collections. | |
763 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) > | |
764 *desired_eden_size_ptr) { | |
765 *desired_eden_size_ptr = | |
766 *desired_eden_size_ptr + scaled_eden_heap_delta; | |
767 } | |
768 set_change_young_gen_for_throughput( | |
769 increase_young_gen_for_througput_true); | |
770 _young_gen_change_for_minor_throughput++; | |
771 } else { | |
772 // EXPERIMENTAL ADJUSTMENT | |
773 // Record that decreasing the young gen size would decrease | |
774 // the minor collection cost but don't do it. | |
775 // *desired_eden_size_ptr = _eden_size - | |
776 // eden_decrement_aligned_down(*desired_eden_size_ptr); | |
777 set_change_young_gen_for_throughput( | |
778 decrease_young_gen_for_througput_true); | |
779 } | |
780 break; | |
781 default: | |
782 if ((*desired_eden_size_ptr + scaled_eden_heap_delta) > | |
783 *desired_eden_size_ptr) { | |
784 *desired_eden_size_ptr = | |
785 *desired_eden_size_ptr + scaled_eden_heap_delta; | |
786 } | |
787 set_change_young_gen_for_throughput( | |
788 increase_young_gen_for_througput_true); | |
789 _young_gen_change_for_minor_throughput++; | |
790 } | |
791 | |
792 if (PrintAdaptiveSizePolicy && Verbose) { | |
793 gclog_or_tty->print_cr( | |
794 "adjusting eden for throughput (avg %f goal %f). desired_eden_size " | |
795 SIZE_FORMAT " eden delta " SIZE_FORMAT "\n", | |
796 mutator_cost(), _throughput_goal, | |
797 *desired_eden_size_ptr, scaled_eden_heap_delta); | |
798 } | |
799 } | |
800 | |
801 size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint( | |
802 size_t desired_promo_size, size_t desired_sum) { | |
803 assert(desired_promo_size <= desired_sum, "Inconsistent parameters"); | |
804 set_decrease_for_footprint(decrease_old_gen_for_footprint_true); | |
805 | |
806 size_t change = promo_decrement(desired_promo_size); | |
807 change = scale_down(change, desired_promo_size, desired_sum); | |
808 | |
809 size_t reduced_size = desired_promo_size - change; | |
810 | |
811 if (PrintAdaptiveSizePolicy && Verbose) { | |
812 gclog_or_tty->print_cr( | |
813 "AdaptiveSizePolicy::compute_generation_free_space " | |
814 "adjusting tenured gen for footprint. " | |
815 "starting promo size " SIZE_FORMAT | |
816 " reduced promo size " SIZE_FORMAT, | |
817 " promo delta " SIZE_FORMAT, | |
818 desired_promo_size, reduced_size, change ); | |
819 } | |
820 | |
821 assert(reduced_size <= desired_promo_size, "Inconsistent result"); | |
822 return reduced_size; | |
823 } | |
824 | |
825 size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint( | |
826 size_t desired_eden_size, size_t desired_sum) { | |
827 assert(desired_eden_size <= desired_sum, "Inconsistent parameters"); | |
828 set_decrease_for_footprint(decrease_young_gen_for_footprint_true); | |
829 | |
830 size_t change = eden_decrement(desired_eden_size); | |
831 change = scale_down(change, desired_eden_size, desired_sum); | |
832 | |
833 size_t reduced_size = desired_eden_size - change; | |
834 | |
835 if (PrintAdaptiveSizePolicy && Verbose) { | |
836 gclog_or_tty->print_cr( | |
837 "AdaptiveSizePolicy::compute_generation_free_space " | |
838 "adjusting eden for footprint. " | |
839 " starting eden size " SIZE_FORMAT | |
840 " reduced eden size " SIZE_FORMAT | |
841 " eden delta " SIZE_FORMAT, | |
842 desired_eden_size, reduced_size, change); | |
843 } | |
844 | |
845 assert(reduced_size <= desired_eden_size, "Inconsistent result"); | |
846 return reduced_size; | |
847 } | |
848 | |
849 // Scale down "change" by the factor | |
850 // part / total | |
851 // Don't align the results. | |
852 | |
853 size_t PSAdaptiveSizePolicy::scale_down(size_t change, | |
854 double part, | |
855 double total) { | |
856 assert(part <= total, "Inconsistent input"); | |
857 size_t reduced_change = change; | |
858 if (total > 0) { | |
859 double fraction = part / total; | |
860 reduced_change = (size_t) (fraction * (double) change); | |
861 } | |
862 assert(reduced_change <= change, "Inconsistent result"); | |
863 return reduced_change; | |
864 } | |
865 | |
866 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden, | |
867 uint percent_change) { | |
868 size_t eden_heap_delta; | |
869 eden_heap_delta = cur_eden / 100 * percent_change; | |
870 return eden_heap_delta; | |
871 } | |
872 | |
873 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) { | |
874 return eden_increment(cur_eden, YoungGenerationSizeIncrement); | |
875 } | |
876 | |
877 size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) { | |
878 size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement); | |
879 return align_size_up(result, _intra_generation_alignment); | |
880 } | |
881 | |
882 size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) { | |
883 size_t result = eden_increment(cur_eden); | |
884 return align_size_down(result, _intra_generation_alignment); | |
885 } | |
886 | |
887 size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up( | |
888 size_t cur_eden) { | |
889 size_t result = eden_increment(cur_eden, | |
890 YoungGenerationSizeIncrement + _young_gen_size_increment_supplement); | |
891 return align_size_up(result, _intra_generation_alignment); | |
892 } | |
893 | |
894 size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) { | |
895 size_t eden_heap_delta = eden_decrement(cur_eden); | |
896 return align_size_down(eden_heap_delta, _intra_generation_alignment); | |
897 } | |
898 | |
899 size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) { | |
900 size_t eden_heap_delta = eden_increment(cur_eden) / | |
901 AdaptiveSizeDecrementScaleFactor; | |
902 return eden_heap_delta; | |
903 } | |
904 | |
905 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo, | |
906 uint percent_change) { | |
907 size_t promo_heap_delta; | |
908 promo_heap_delta = cur_promo / 100 * percent_change; | |
909 return promo_heap_delta; | |
910 } | |
911 | |
912 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) { | |
913 return promo_increment(cur_promo, TenuredGenerationSizeIncrement); | |
914 } | |
915 | |
916 size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) { | |
917 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement); | |
918 return align_size_up(result, _intra_generation_alignment); | |
919 } | |
920 | |
921 size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) { | |
922 size_t result = promo_increment(cur_promo, TenuredGenerationSizeIncrement); | |
923 return align_size_down(result, _intra_generation_alignment); | |
924 } | |
925 | |
926 size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up( | |
927 size_t cur_promo) { | |
928 size_t result = promo_increment(cur_promo, | |
929 TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement); | |
930 return align_size_up(result, _intra_generation_alignment); | |
931 } | |
932 | |
933 size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) { | |
934 size_t promo_heap_delta = promo_decrement(cur_promo); | |
935 return align_size_down(promo_heap_delta, _intra_generation_alignment); | |
936 } | |
937 | |
938 size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) { | |
939 size_t promo_heap_delta = promo_increment(cur_promo); | |
940 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor; | |
941 return promo_heap_delta; | |
942 } | |
943 | |
944 int PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold( | |
945 bool is_survivor_overflow, | |
946 int tenuring_threshold, | |
947 size_t survivor_limit) { | |
948 assert(survivor_limit >= _intra_generation_alignment, | |
949 "survivor_limit too small"); | |
950 assert((size_t)align_size_down(survivor_limit, _intra_generation_alignment) | |
951 == survivor_limit, "survivor_limit not aligned"); | |
952 | |
953 // This method is called even if the tenuring threshold and survivor | |
954 // spaces are not adjusted so that the averages are sampled above. | |
955 if (!UsePSAdaptiveSurvivorSizePolicy || | |
956 !young_gen_policy_is_ready()) { | |
957 return tenuring_threshold; | |
958 } | |
959 | |
960 // We'll decide whether to increase or decrease the tenuring | |
961 // threshold based partly on the newly computed survivor size | |
962 // (if we hit the maximum limit allowed, we'll always choose to | |
963 // decrement the threshold). | |
964 bool incr_tenuring_threshold = false; | |
965 bool decr_tenuring_threshold = false; | |
966 | |
967 set_decrement_tenuring_threshold_for_gc_cost(false); | |
968 set_increment_tenuring_threshold_for_gc_cost(false); | |
969 set_decrement_tenuring_threshold_for_survivor_limit(false); | |
970 | |
971 if (!is_survivor_overflow) { | |
972 // Keep running averages on how much survived | |
973 | |
974 // We use the tenuring threshold to equalize the cost of major | |
975 // and minor collections. | |
976 // ThresholdTolerance is used to indicate how sensitive the | |
977 // tenuring threshold is to differences in cost betweent the | |
978 // collection types. | |
979 | |
980 // Get the times of interest. This involves a little work, so | |
981 // we cache the values here. | |
982 const double major_cost = major_gc_cost(); | |
983 const double minor_cost = minor_gc_cost(); | |
984 | |
985 if (minor_cost > major_cost * _threshold_tolerance_percent) { | |
986 // Minor times are getting too long; lower the threshold so | |
987 // less survives and more is promoted. | |
988 decr_tenuring_threshold = true; | |
989 set_decrement_tenuring_threshold_for_gc_cost(true); | |
990 } else if (major_cost > minor_cost * _threshold_tolerance_percent) { | |
991 // Major times are too long, so we want less promotion. | |
992 incr_tenuring_threshold = true; | |
993 set_increment_tenuring_threshold_for_gc_cost(true); | |
994 } | |
995 | |
996 } else { | |
997 // Survivor space overflow occurred, so promoted and survived are | |
998 // not accurate. We'll make our best guess by combining survived | |
999 // and promoted and count them as survivors. | |
1000 // | |
1001 // We'll lower the tenuring threshold to see if we can correct | |
1002 // things. Also, set the survivor size conservatively. We're | |
1003 // trying to avoid many overflows from occurring if defnew size | |
1004 // is just too small. | |
1005 | |
1006 decr_tenuring_threshold = true; | |
1007 } | |
1008 | |
1009 // The padded average also maintains a deviation from the average; | |
1010 // we use this to see how good of an estimate we have of what survived. | |
1011 // We're trying to pad the survivor size as little as possible without | |
1012 // overflowing the survivor spaces. | |
1013 size_t target_size = align_size_up((size_t)_avg_survived->padded_average(), | |
1014 _intra_generation_alignment); | |
1015 target_size = MAX2(target_size, _intra_generation_alignment); | |
1016 | |
1017 if (target_size > survivor_limit) { | |
1018 // Target size is bigger than we can handle. Let's also reduce | |
1019 // the tenuring threshold. | |
1020 target_size = survivor_limit; | |
1021 decr_tenuring_threshold = true; | |
1022 set_decrement_tenuring_threshold_for_survivor_limit(true); | |
1023 } | |
1024 | |
1025 // Finally, increment or decrement the tenuring threshold, as decided above. | |
1026 // We test for decrementing first, as we might have hit the target size | |
1027 // limit. | |
1028 if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) { | |
1029 if (tenuring_threshold > 1) { | |
1030 tenuring_threshold--; | |
1031 } | |
1032 } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) { | |
1033 if (tenuring_threshold < MaxTenuringThreshold) { | |
1034 tenuring_threshold++; | |
1035 } | |
1036 } | |
1037 | |
1038 // We keep a running average of the amount promoted which is used | |
1039 // to decide when we should collect the old generation (when | |
1040 // the amount of old gen free space is less than what we expect to | |
1041 // promote). | |
1042 | |
1043 if (PrintAdaptiveSizePolicy) { | |
1044 // A little more detail if Verbose is on | |
1045 if (Verbose) { | |
1046 gclog_or_tty->print( " avg_survived: %f" | |
1047 " avg_deviation: %f", | |
1048 _avg_survived->average(), | |
1049 _avg_survived->deviation()); | |
1050 } | |
1051 | |
1052 gclog_or_tty->print( " avg_survived_padded_avg: %f", | |
1053 _avg_survived->padded_average()); | |
1054 | |
1055 if (Verbose) { | |
1056 gclog_or_tty->print( " avg_promoted_avg: %f" | |
1057 " avg_promoted_dev: %f", | |
1058 avg_promoted()->average(), | |
1059 avg_promoted()->deviation()); | |
1060 } | |
1061 | |
1062 gclog_or_tty->print( " avg_promoted_padded_avg: %f" | |
1063 " avg_pretenured_padded_avg: %f" | |
1064 " tenuring_thresh: %d" | |
1065 " target_size: " SIZE_FORMAT, | |
1066 avg_promoted()->padded_average(), | |
1067 _avg_pretenured->padded_average(), | |
1068 tenuring_threshold, target_size); | |
1069 tty->cr(); | |
1070 } | |
1071 | |
1072 set_survivor_size(target_size); | |
1073 | |
1074 return tenuring_threshold; | |
1075 } | |
1076 | |
1077 void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow, | |
1078 size_t survived, | |
1079 size_t promoted) { | |
1080 // Update averages | |
1081 if (!is_survivor_overflow) { | |
1082 // Keep running averages on how much survived | |
1083 _avg_survived->sample(survived); | |
1084 } else { | |
1085 size_t survived_guess = survived + promoted; | |
1086 _avg_survived->sample(survived_guess); | |
1087 } | |
1088 avg_promoted()->sample(promoted + _avg_pretenured->padded_average()); | |
1089 | |
1090 if (PrintAdaptiveSizePolicy) { | |
1091 gclog_or_tty->print( | |
1092 "AdaptiveSizePolicy::compute_survivor_space_size_and_thresh:" | |
1093 " survived: " SIZE_FORMAT | |
1094 " promoted: " SIZE_FORMAT | |
1095 " overflow: %s", | |
1096 survived, promoted, is_survivor_overflow ? "true" : "false"); | |
1097 } | |
1098 } | |
1099 | |
1100 bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) | |
1101 const { | |
1102 | |
1103 if (!UseAdaptiveSizePolicy) return false; | |
1104 | |
1105 return AdaptiveSizePolicy::print_adaptive_size_policy_on( | |
1106 st, | |
1107 PSScavenge::tenuring_threshold()); | |
1108 } |