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src/share/vm/gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.cpp@f90c822e73f8
src/share/vm/gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.cpp
Wed, 27 Apr 2016 01:25:04 +0800
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- aoqi
- date
- Wed, 27 Apr 2016 01:25:04 +0800
- changeset 0
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http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/
changeset: 6782:28b50d07f6f8
tag: jdk8u25-b17
1 /*
2 * Copyright (c) 2004, 2013, 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 */
25 #include "precompiled.hpp"
26 #include "gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp"
27 #include "gc_implementation/shared/gcStats.hpp"
28 #include "memory/defNewGeneration.hpp"
29 #include "memory/genCollectedHeap.hpp"
30 #include "runtime/thread.hpp"
31 #ifdef TARGET_OS_FAMILY_linux
32 # include "os_linux.inline.hpp"
33 #endif
34 #ifdef TARGET_OS_FAMILY_solaris
35 # include "os_solaris.inline.hpp"
36 #endif
37 #ifdef TARGET_OS_FAMILY_windows
38 # include "os_windows.inline.hpp"
39 #endif
40 #ifdef TARGET_OS_FAMILY_aix
41 # include "os_aix.inline.hpp"
42 #endif
43 #ifdef TARGET_OS_FAMILY_bsd
44 # include "os_bsd.inline.hpp"
45 #endif
46 elapsedTimer CMSAdaptiveSizePolicy::_concurrent_timer;
47 elapsedTimer CMSAdaptiveSizePolicy::_STW_timer;
49 // Defined if the granularity of the time measurements is potentially too large.
50 #define CLOCK_GRANULARITY_TOO_LARGE
52 CMSAdaptiveSizePolicy::CMSAdaptiveSizePolicy(size_t init_eden_size,
53 size_t init_promo_size,
54 size_t init_survivor_size,
55 double max_gc_minor_pause_sec,
56 double max_gc_pause_sec,
57 uint gc_cost_ratio) :
58 AdaptiveSizePolicy(init_eden_size,
59 init_promo_size,
60 init_survivor_size,
61 max_gc_pause_sec,
62 gc_cost_ratio) {
64 clear_internal_time_intervals();
66 _processor_count = os::active_processor_count();
68 if (CMSConcurrentMTEnabled && (ConcGCThreads > 1)) {
69 assert(_processor_count > 0, "Processor count is suspect");
70 _concurrent_processor_count = MIN2((uint) ConcGCThreads,
71 (uint) _processor_count);
72 } else {
73 _concurrent_processor_count = 1;
74 }
76 _avg_concurrent_time = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
77 _avg_concurrent_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
78 _avg_concurrent_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
80 _avg_initial_pause = new AdaptivePaddedAverage(AdaptiveTimeWeight,
81 PausePadding);
82 _avg_remark_pause = new AdaptivePaddedAverage(AdaptiveTimeWeight,
83 PausePadding);
85 _avg_cms_STW_time = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
86 _avg_cms_STW_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
88 _avg_cms_free = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
89 _avg_cms_free_at_sweep = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
90 _avg_cms_promo = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
92 // Mark-sweep-compact
93 _avg_msc_pause = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
94 _avg_msc_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
95 _avg_msc_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
97 // Mark-sweep
98 _avg_ms_pause = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
99 _avg_ms_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
100 _avg_ms_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
102 // Variables that estimate pause times as a function of generation
103 // size.
104 _remark_pause_old_estimator =
105 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
106 _initial_pause_old_estimator =
107 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
108 _remark_pause_young_estimator =
109 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
110 _initial_pause_young_estimator =
111 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
113 // Alignment comes from that used in ReservedSpace.
114 _generation_alignment = os::vm_allocation_granularity();
116 // Start the concurrent timer here so that the first
117 // concurrent_phases_begin() measures a finite mutator
118 // time. A finite mutator time is used to determine
119 // if a concurrent collection has been started. If this
120 // proves to be a problem, use some explicit flag to
121 // signal that a concurrent collection has been started.
122 _concurrent_timer.start();
123 _STW_timer.start();
124 }
126 double CMSAdaptiveSizePolicy::concurrent_processor_fraction() {
127 // For now assume no other daemon threads are taking alway
128 // cpu's from the application.
129 return ((double) _concurrent_processor_count / (double) _processor_count);
130 }
132 double CMSAdaptiveSizePolicy::concurrent_collection_cost(
133 double interval_in_seconds) {
134 // When the precleaning and sweeping phases use multiple
135 // threads, change one_processor_fraction to
136 // concurrent_processor_fraction().
137 double one_processor_fraction = 1.0 / ((double) processor_count());
138 double concurrent_cost =
139 collection_cost(_latest_cms_concurrent_marking_time_secs,
140 interval_in_seconds) * concurrent_processor_fraction() +
141 collection_cost(_latest_cms_concurrent_precleaning_time_secs,
142 interval_in_seconds) * one_processor_fraction +
143 collection_cost(_latest_cms_concurrent_sweeping_time_secs,
144 interval_in_seconds) * one_processor_fraction;
145 if (PrintAdaptiveSizePolicy && Verbose) {
146 gclog_or_tty->print_cr(
147 "\nCMSAdaptiveSizePolicy::scaled_concurrent_collection_cost(%f) "
148 "_latest_cms_concurrent_marking_cost %f "
149 "_latest_cms_concurrent_precleaning_cost %f "
150 "_latest_cms_concurrent_sweeping_cost %f "
151 "concurrent_processor_fraction %f "
152 "concurrent_cost %f ",
153 interval_in_seconds,
154 collection_cost(_latest_cms_concurrent_marking_time_secs,
155 interval_in_seconds),
156 collection_cost(_latest_cms_concurrent_precleaning_time_secs,
157 interval_in_seconds),
158 collection_cost(_latest_cms_concurrent_sweeping_time_secs,
159 interval_in_seconds),
160 concurrent_processor_fraction(),
161 concurrent_cost);
162 }
163 return concurrent_cost;
164 }
166 double CMSAdaptiveSizePolicy::concurrent_collection_time() {
167 double latest_cms_sum_concurrent_phases_time_secs =
168 _latest_cms_concurrent_marking_time_secs +
169 _latest_cms_concurrent_precleaning_time_secs +
170 _latest_cms_concurrent_sweeping_time_secs;
171 return latest_cms_sum_concurrent_phases_time_secs;
172 }
174 double CMSAdaptiveSizePolicy::scaled_concurrent_collection_time() {
175 // When the precleaning and sweeping phases use multiple
176 // threads, change one_processor_fraction to
177 // concurrent_processor_fraction().
178 double one_processor_fraction = 1.0 / ((double) processor_count());
179 double latest_cms_sum_concurrent_phases_time_secs =
180 _latest_cms_concurrent_marking_time_secs * concurrent_processor_fraction() +
181 _latest_cms_concurrent_precleaning_time_secs * one_processor_fraction +
182 _latest_cms_concurrent_sweeping_time_secs * one_processor_fraction ;
183 if (PrintAdaptiveSizePolicy && Verbose) {
184 gclog_or_tty->print_cr(
185 "\nCMSAdaptiveSizePolicy::scaled_concurrent_collection_time "
186 "_latest_cms_concurrent_marking_time_secs %f "
187 "_latest_cms_concurrent_precleaning_time_secs %f "
188 "_latest_cms_concurrent_sweeping_time_secs %f "
189 "concurrent_processor_fraction %f "
190 "latest_cms_sum_concurrent_phases_time_secs %f ",
191 _latest_cms_concurrent_marking_time_secs,
192 _latest_cms_concurrent_precleaning_time_secs,
193 _latest_cms_concurrent_sweeping_time_secs,
194 concurrent_processor_fraction(),
195 latest_cms_sum_concurrent_phases_time_secs);
196 }
197 return latest_cms_sum_concurrent_phases_time_secs;
198 }
200 void CMSAdaptiveSizePolicy::update_minor_pause_old_estimator(
201 double minor_pause_in_ms) {
202 // Get the equivalent of the free space
203 // that is available for promotions in the CMS generation
204 // and use that to update _minor_pause_old_estimator
206 // Don't implement this until it is needed. A warning is
207 // printed if _minor_pause_old_estimator is used.
208 }
210 void CMSAdaptiveSizePolicy::concurrent_marking_begin() {
211 if (PrintAdaptiveSizePolicy && Verbose) {
212 gclog_or_tty->print(" ");
213 gclog_or_tty->stamp();
214 gclog_or_tty->print(": concurrent_marking_begin ");
215 }
216 // Update the interval time
217 _concurrent_timer.stop();
218 _latest_cms_collection_end_to_collection_start_secs = _concurrent_timer.seconds();
219 if (PrintAdaptiveSizePolicy && Verbose) {
220 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_marking_begin: "
221 "mutator time %f", _latest_cms_collection_end_to_collection_start_secs);
222 }
223 _concurrent_timer.reset();
224 _concurrent_timer.start();
225 }
227 void CMSAdaptiveSizePolicy::concurrent_marking_end() {
228 if (PrintAdaptiveSizePolicy && Verbose) {
229 gclog_or_tty->stamp();
230 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_marking_end()");
231 }
233 _concurrent_timer.stop();
234 _latest_cms_concurrent_marking_time_secs = _concurrent_timer.seconds();
236 if (PrintAdaptiveSizePolicy && Verbose) {
237 gclog_or_tty->print_cr("\n CMSAdaptiveSizePolicy::concurrent_marking_end"
238 ":concurrent marking time (s) %f",
239 _latest_cms_concurrent_marking_time_secs);
240 }
241 }
243 void CMSAdaptiveSizePolicy::concurrent_precleaning_begin() {
244 if (PrintAdaptiveSizePolicy && Verbose) {
245 gclog_or_tty->stamp();
246 gclog_or_tty->print_cr(
247 "CMSAdaptiveSizePolicy::concurrent_precleaning_begin()");
248 }
249 _concurrent_timer.reset();
250 _concurrent_timer.start();
251 }
254 void CMSAdaptiveSizePolicy::concurrent_precleaning_end() {
255 if (PrintAdaptiveSizePolicy && Verbose) {
256 gclog_or_tty->stamp();
257 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_precleaning_end()");
258 }
260 _concurrent_timer.stop();
261 // May be set again by a second call during the same collection.
262 _latest_cms_concurrent_precleaning_time_secs = _concurrent_timer.seconds();
264 if (PrintAdaptiveSizePolicy && Verbose) {
265 gclog_or_tty->print_cr("\n CMSAdaptiveSizePolicy::concurrent_precleaning_end"
266 ":concurrent precleaning time (s) %f",
267 _latest_cms_concurrent_precleaning_time_secs);
268 }
269 }
271 void CMSAdaptiveSizePolicy::concurrent_sweeping_begin() {
272 if (PrintAdaptiveSizePolicy && Verbose) {
273 gclog_or_tty->stamp();
274 gclog_or_tty->print_cr(
275 "CMSAdaptiveSizePolicy::concurrent_sweeping_begin()");
276 }
277 _concurrent_timer.reset();
278 _concurrent_timer.start();
279 }
282 void CMSAdaptiveSizePolicy::concurrent_sweeping_end() {
283 if (PrintAdaptiveSizePolicy && Verbose) {
284 gclog_or_tty->stamp();
285 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_sweeping_end()");
286 }
288 _concurrent_timer.stop();
289 _latest_cms_concurrent_sweeping_time_secs = _concurrent_timer.seconds();
291 if (PrintAdaptiveSizePolicy && Verbose) {
292 gclog_or_tty->print_cr("\n CMSAdaptiveSizePolicy::concurrent_sweeping_end"
293 ":concurrent sweeping time (s) %f",
294 _latest_cms_concurrent_sweeping_time_secs);
295 }
296 }
298 void CMSAdaptiveSizePolicy::concurrent_phases_end(GCCause::Cause gc_cause,
299 size_t cur_eden,
300 size_t cur_promo) {
301 if (PrintAdaptiveSizePolicy && Verbose) {
302 gclog_or_tty->print(" ");
303 gclog_or_tty->stamp();
304 gclog_or_tty->print(": concurrent_phases_end ");
305 }
307 // Update the concurrent timer
308 _concurrent_timer.stop();
310 if (gc_cause != GCCause::_java_lang_system_gc ||
311 UseAdaptiveSizePolicyWithSystemGC) {
313 avg_cms_free()->sample(cur_promo);
314 double latest_cms_sum_concurrent_phases_time_secs =
315 concurrent_collection_time();
317 _avg_concurrent_time->sample(latest_cms_sum_concurrent_phases_time_secs);
319 // Cost of collection (unit-less)
321 // Total interval for collection. May not be valid. Tests
322 // below determine whether to use this.
323 //
324 if (PrintAdaptiveSizePolicy && Verbose) {
325 gclog_or_tty->print_cr("\nCMSAdaptiveSizePolicy::concurrent_phases_end \n"
326 "_latest_cms_reset_end_to_initial_mark_start_secs %f \n"
327 "_latest_cms_initial_mark_start_to_end_time_secs %f \n"
328 "_latest_cms_remark_start_to_end_time_secs %f \n"
329 "_latest_cms_concurrent_marking_time_secs %f \n"
330 "_latest_cms_concurrent_precleaning_time_secs %f \n"
331 "_latest_cms_concurrent_sweeping_time_secs %f \n"
332 "latest_cms_sum_concurrent_phases_time_secs %f \n"
333 "_latest_cms_collection_end_to_collection_start_secs %f \n"
334 "concurrent_processor_fraction %f",
335 _latest_cms_reset_end_to_initial_mark_start_secs,
336 _latest_cms_initial_mark_start_to_end_time_secs,
337 _latest_cms_remark_start_to_end_time_secs,
338 _latest_cms_concurrent_marking_time_secs,
339 _latest_cms_concurrent_precleaning_time_secs,
340 _latest_cms_concurrent_sweeping_time_secs,
341 latest_cms_sum_concurrent_phases_time_secs,
342 _latest_cms_collection_end_to_collection_start_secs,
343 concurrent_processor_fraction());
344 }
345 double interval_in_seconds =
346 _latest_cms_initial_mark_start_to_end_time_secs +
347 _latest_cms_remark_start_to_end_time_secs +
348 latest_cms_sum_concurrent_phases_time_secs +
349 _latest_cms_collection_end_to_collection_start_secs;
350 assert(interval_in_seconds >= 0.0,
351 "Bad interval between cms collections");
353 // Sample for performance counter
354 avg_concurrent_interval()->sample(interval_in_seconds);
356 // STW costs (initial and remark pauses)
357 // Cost of collection (unit-less)
358 assert(_latest_cms_initial_mark_start_to_end_time_secs >= 0.0,
359 "Bad initial mark pause");
360 assert(_latest_cms_remark_start_to_end_time_secs >= 0.0,
361 "Bad remark pause");
362 double STW_time_in_seconds =
363 _latest_cms_initial_mark_start_to_end_time_secs +
364 _latest_cms_remark_start_to_end_time_secs;
365 double STW_collection_cost = 0.0;
366 if (interval_in_seconds > 0.0) {
367 // cost for the STW phases of the concurrent collection.
368 STW_collection_cost = STW_time_in_seconds / interval_in_seconds;
369 avg_cms_STW_gc_cost()->sample(STW_collection_cost);
370 }
371 if (PrintAdaptiveSizePolicy && Verbose) {
372 gclog_or_tty->print("cmsAdaptiveSizePolicy::STW_collection_end: "
373 "STW gc cost: %f average: %f", STW_collection_cost,
374 avg_cms_STW_gc_cost()->average());
375 gclog_or_tty->print_cr(" STW pause: %f (ms) STW period %f (ms)",
376 (double) STW_time_in_seconds * MILLIUNITS,
377 (double) interval_in_seconds * MILLIUNITS);
378 }
380 double concurrent_cost = 0.0;
381 if (latest_cms_sum_concurrent_phases_time_secs > 0.0) {
382 concurrent_cost = concurrent_collection_cost(interval_in_seconds);
384 avg_concurrent_gc_cost()->sample(concurrent_cost);
385 // Average this ms cost into all the other types gc costs
387 if (PrintAdaptiveSizePolicy && Verbose) {
388 gclog_or_tty->print("cmsAdaptiveSizePolicy::concurrent_phases_end: "
389 "concurrent gc cost: %f average: %f",
390 concurrent_cost,
391 _avg_concurrent_gc_cost->average());
392 gclog_or_tty->print_cr(" concurrent time: %f (ms) cms period %f (ms)"
393 " processor fraction: %f",
394 latest_cms_sum_concurrent_phases_time_secs * MILLIUNITS,
395 interval_in_seconds * MILLIUNITS,
396 concurrent_processor_fraction());
397 }
398 }
399 double total_collection_cost = STW_collection_cost + concurrent_cost;
400 avg_major_gc_cost()->sample(total_collection_cost);
402 // Gather information for estimating future behavior
403 double initial_pause_in_ms = _latest_cms_initial_mark_start_to_end_time_secs * MILLIUNITS;
404 double remark_pause_in_ms = _latest_cms_remark_start_to_end_time_secs * MILLIUNITS;
406 double cur_promo_size_in_mbytes = ((double)cur_promo)/((double)M);
407 initial_pause_old_estimator()->update(cur_promo_size_in_mbytes,
408 initial_pause_in_ms);
409 remark_pause_old_estimator()->update(cur_promo_size_in_mbytes,
410 remark_pause_in_ms);
411 major_collection_estimator()->update(cur_promo_size_in_mbytes,
412 total_collection_cost);
414 // This estimate uses the average eden size. It could also
415 // have used the latest eden size. Which is better?
416 double cur_eden_size_in_mbytes = ((double)cur_eden)/((double) M);
417 initial_pause_young_estimator()->update(cur_eden_size_in_mbytes,
418 initial_pause_in_ms);
419 remark_pause_young_estimator()->update(cur_eden_size_in_mbytes,
420 remark_pause_in_ms);
421 }
423 clear_internal_time_intervals();
425 set_first_after_collection();
427 // The concurrent phases keeps track of it's own mutator interval
428 // with this timer. This allows the stop-the-world phase to
429 // be included in the mutator time so that the stop-the-world time
430 // is not double counted. Reset and start it.
431 _concurrent_timer.reset();
432 _concurrent_timer.start();
434 // The mutator time between STW phases does not include the
435 // concurrent collection time.
436 _STW_timer.reset();
437 _STW_timer.start();
438 }
440 void CMSAdaptiveSizePolicy::checkpoint_roots_initial_begin() {
441 // Update the interval time
442 _STW_timer.stop();
443 _latest_cms_reset_end_to_initial_mark_start_secs = _STW_timer.seconds();
444 // Reset for the initial mark
445 _STW_timer.reset();
446 _STW_timer.start();
447 }
449 void CMSAdaptiveSizePolicy::checkpoint_roots_initial_end(
450 GCCause::Cause gc_cause) {
451 _STW_timer.stop();
453 if (gc_cause != GCCause::_java_lang_system_gc ||
454 UseAdaptiveSizePolicyWithSystemGC) {
455 _latest_cms_initial_mark_start_to_end_time_secs = _STW_timer.seconds();
456 avg_initial_pause()->sample(_latest_cms_initial_mark_start_to_end_time_secs);
458 if (PrintAdaptiveSizePolicy && Verbose) {
459 gclog_or_tty->print(
460 "cmsAdaptiveSizePolicy::checkpoint_roots_initial_end: "
461 "initial pause: %f ", _latest_cms_initial_mark_start_to_end_time_secs);
462 }
463 }
465 _STW_timer.reset();
466 _STW_timer.start();
467 }
469 void CMSAdaptiveSizePolicy::checkpoint_roots_final_begin() {
470 _STW_timer.stop();
471 _latest_cms_initial_mark_end_to_remark_start_secs = _STW_timer.seconds();
472 // Start accumumlating time for the remark in the STW timer.
473 _STW_timer.reset();
474 _STW_timer.start();
475 }
477 void CMSAdaptiveSizePolicy::checkpoint_roots_final_end(
478 GCCause::Cause gc_cause) {
479 _STW_timer.stop();
480 if (gc_cause != GCCause::_java_lang_system_gc ||
481 UseAdaptiveSizePolicyWithSystemGC) {
482 // Total initial mark pause + remark pause.
483 _latest_cms_remark_start_to_end_time_secs = _STW_timer.seconds();
484 double STW_time_in_seconds = _latest_cms_initial_mark_start_to_end_time_secs +
485 _latest_cms_remark_start_to_end_time_secs;
486 double STW_time_in_ms = STW_time_in_seconds * MILLIUNITS;
488 avg_remark_pause()->sample(_latest_cms_remark_start_to_end_time_secs);
490 // Sample total for initial mark + remark
491 avg_cms_STW_time()->sample(STW_time_in_seconds);
493 if (PrintAdaptiveSizePolicy && Verbose) {
494 gclog_or_tty->print("cmsAdaptiveSizePolicy::checkpoint_roots_final_end: "
495 "remark pause: %f", _latest_cms_remark_start_to_end_time_secs);
496 }
498 }
499 // Don't start the STW times here because the concurrent
500 // sweep and reset has not happened.
501 // Keep the old comment above in case I don't understand
502 // what is going on but now
503 // Start the STW timer because it is used by ms_collection_begin()
504 // and ms_collection_end() to get the sweep time if a MS is being
505 // done in the foreground.
506 _STW_timer.reset();
507 _STW_timer.start();
508 }
510 void CMSAdaptiveSizePolicy::msc_collection_begin() {
511 if (PrintAdaptiveSizePolicy && Verbose) {
512 gclog_or_tty->print(" ");
513 gclog_or_tty->stamp();
514 gclog_or_tty->print(": msc_collection_begin ");
515 }
516 _STW_timer.stop();
517 _latest_cms_msc_end_to_msc_start_time_secs = _STW_timer.seconds();
518 if (PrintAdaptiveSizePolicy && Verbose) {
519 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::msc_collection_begin: "
520 "mutator time %f",
521 _latest_cms_msc_end_to_msc_start_time_secs);
522 }
523 avg_msc_interval()->sample(_latest_cms_msc_end_to_msc_start_time_secs);
524 _STW_timer.reset();
525 _STW_timer.start();
526 }
528 void CMSAdaptiveSizePolicy::msc_collection_end(GCCause::Cause gc_cause) {
529 if (PrintAdaptiveSizePolicy && Verbose) {
530 gclog_or_tty->print(" ");
531 gclog_or_tty->stamp();
532 gclog_or_tty->print(": msc_collection_end ");
533 }
534 _STW_timer.stop();
535 if (gc_cause != GCCause::_java_lang_system_gc ||
536 UseAdaptiveSizePolicyWithSystemGC) {
537 double msc_pause_in_seconds = _STW_timer.seconds();
538 if ((_latest_cms_msc_end_to_msc_start_time_secs > 0.0) &&
539 (msc_pause_in_seconds > 0.0)) {
540 avg_msc_pause()->sample(msc_pause_in_seconds);
541 double mutator_time_in_seconds = 0.0;
542 if (_latest_cms_collection_end_to_collection_start_secs == 0.0) {
543 // This assertion may fail because of time stamp gradularity.
544 // Comment it out and investiage it at a later time. The large
545 // time stamp granularity occurs on some older linux systems.
546 #ifndef CLOCK_GRANULARITY_TOO_LARGE
547 assert((_latest_cms_concurrent_marking_time_secs == 0.0) &&
548 (_latest_cms_concurrent_precleaning_time_secs == 0.0) &&
549 (_latest_cms_concurrent_sweeping_time_secs == 0.0),
550 "There should not be any concurrent time");
551 #endif
552 // A concurrent collection did not start. Mutator time
553 // between collections comes from the STW MSC timer.
554 mutator_time_in_seconds = _latest_cms_msc_end_to_msc_start_time_secs;
555 } else {
556 // The concurrent collection did start so count the mutator
557 // time to the start of the concurrent collection. In this
558 // case the _latest_cms_msc_end_to_msc_start_time_secs measures
559 // the time between the initial mark or remark and the
560 // start of the MSC. That has no real meaning.
561 mutator_time_in_seconds = _latest_cms_collection_end_to_collection_start_secs;
562 }
564 double latest_cms_sum_concurrent_phases_time_secs =
565 concurrent_collection_time();
566 double interval_in_seconds =
567 mutator_time_in_seconds +
568 _latest_cms_initial_mark_start_to_end_time_secs +
569 _latest_cms_remark_start_to_end_time_secs +
570 latest_cms_sum_concurrent_phases_time_secs +
571 msc_pause_in_seconds;
573 if (PrintAdaptiveSizePolicy && Verbose) {
574 gclog_or_tty->print_cr(" interval_in_seconds %f \n"
575 " mutator_time_in_seconds %f \n"
576 " _latest_cms_initial_mark_start_to_end_time_secs %f\n"
577 " _latest_cms_remark_start_to_end_time_secs %f\n"
578 " latest_cms_sum_concurrent_phases_time_secs %f\n"
579 " msc_pause_in_seconds %f\n",
580 interval_in_seconds,
581 mutator_time_in_seconds,
582 _latest_cms_initial_mark_start_to_end_time_secs,
583 _latest_cms_remark_start_to_end_time_secs,
584 latest_cms_sum_concurrent_phases_time_secs,
585 msc_pause_in_seconds);
586 }
588 // The concurrent cost is wasted cost but it should be
589 // included.
590 double concurrent_cost = concurrent_collection_cost(interval_in_seconds);
592 // Initial mark and remark, also wasted.
593 double STW_time_in_seconds = _latest_cms_initial_mark_start_to_end_time_secs +
594 _latest_cms_remark_start_to_end_time_secs;
595 double STW_collection_cost =
596 collection_cost(STW_time_in_seconds, interval_in_seconds) +
597 concurrent_cost;
599 if (PrintAdaptiveSizePolicy && Verbose) {
600 gclog_or_tty->print_cr(" msc_collection_end:\n"
601 "_latest_cms_collection_end_to_collection_start_secs %f\n"
602 "_latest_cms_msc_end_to_msc_start_time_secs %f\n"
603 "_latest_cms_initial_mark_start_to_end_time_secs %f\n"
604 "_latest_cms_remark_start_to_end_time_secs %f\n"
605 "latest_cms_sum_concurrent_phases_time_secs %f\n",
606 _latest_cms_collection_end_to_collection_start_secs,
607 _latest_cms_msc_end_to_msc_start_time_secs,
608 _latest_cms_initial_mark_start_to_end_time_secs,
609 _latest_cms_remark_start_to_end_time_secs,
610 latest_cms_sum_concurrent_phases_time_secs);
612 gclog_or_tty->print_cr(" msc_collection_end: \n"
613 "latest_cms_sum_concurrent_phases_time_secs %f\n"
614 "STW_time_in_seconds %f\n"
615 "msc_pause_in_seconds %f\n",
616 latest_cms_sum_concurrent_phases_time_secs,
617 STW_time_in_seconds,
618 msc_pause_in_seconds);
619 }
621 double cost = concurrent_cost + STW_collection_cost +
622 collection_cost(msc_pause_in_seconds, interval_in_seconds);
624 _avg_msc_gc_cost->sample(cost);
626 // Average this ms cost into all the other types gc costs
627 avg_major_gc_cost()->sample(cost);
629 // Sample for performance counter
630 _avg_msc_interval->sample(interval_in_seconds);
631 if (PrintAdaptiveSizePolicy && Verbose) {
632 gclog_or_tty->print("cmsAdaptiveSizePolicy::msc_collection_end: "
633 "MSC gc cost: %f average: %f", cost,
634 _avg_msc_gc_cost->average());
636 double msc_pause_in_ms = msc_pause_in_seconds * MILLIUNITS;
637 gclog_or_tty->print_cr(" MSC pause: %f (ms) MSC period %f (ms)",
638 msc_pause_in_ms, (double) interval_in_seconds * MILLIUNITS);
639 }
640 }
641 }
643 clear_internal_time_intervals();
645 // Can this call be put into the epilogue?
646 set_first_after_collection();
648 // The concurrent phases keeps track of it's own mutator interval
649 // with this timer. This allows the stop-the-world phase to
650 // be included in the mutator time so that the stop-the-world time
651 // is not double counted. Reset and start it.
652 _concurrent_timer.stop();
653 _concurrent_timer.reset();
654 _concurrent_timer.start();
656 _STW_timer.reset();
657 _STW_timer.start();
658 }
660 void CMSAdaptiveSizePolicy::ms_collection_begin() {
661 if (PrintAdaptiveSizePolicy && Verbose) {
662 gclog_or_tty->print(" ");
663 gclog_or_tty->stamp();
664 gclog_or_tty->print(": ms_collection_begin ");
665 }
666 _STW_timer.stop();
667 _latest_cms_ms_end_to_ms_start = _STW_timer.seconds();
668 if (PrintAdaptiveSizePolicy && Verbose) {
669 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::ms_collection_begin: "
670 "mutator time %f",
671 _latest_cms_ms_end_to_ms_start);
672 }
673 avg_ms_interval()->sample(_STW_timer.seconds());
674 _STW_timer.reset();
675 _STW_timer.start();
676 }
678 void CMSAdaptiveSizePolicy::ms_collection_end(GCCause::Cause gc_cause) {
679 if (PrintAdaptiveSizePolicy && Verbose) {
680 gclog_or_tty->print(" ");
681 gclog_or_tty->stamp();
682 gclog_or_tty->print(": ms_collection_end ");
683 }
684 _STW_timer.stop();
685 if (gc_cause != GCCause::_java_lang_system_gc ||
686 UseAdaptiveSizePolicyWithSystemGC) {
687 // The MS collection is a foreground collection that does all
688 // the parts of a mostly concurrent collection.
689 //
690 // For this collection include the cost of the
691 // initial mark
692 // remark
693 // all concurrent time (scaled down by the
694 // concurrent_processor_fraction). Some
695 // may be zero if the baton was passed before
696 // it was reached.
697 // concurrent marking
698 // sweeping
699 // resetting
700 // STW after baton was passed (STW_in_foreground_in_seconds)
701 double STW_in_foreground_in_seconds = _STW_timer.seconds();
703 double latest_cms_sum_concurrent_phases_time_secs =
704 concurrent_collection_time();
705 if (PrintAdaptiveSizePolicy && Verbose) {
706 gclog_or_tty->print_cr("\nCMSAdaptiveSizePolicy::ms_collecton_end "
707 "STW_in_foreground_in_seconds %f "
708 "_latest_cms_initial_mark_start_to_end_time_secs %f "
709 "_latest_cms_remark_start_to_end_time_secs %f "
710 "latest_cms_sum_concurrent_phases_time_secs %f "
711 "_latest_cms_ms_marking_start_to_end_time_secs %f "
712 "_latest_cms_ms_end_to_ms_start %f",
713 STW_in_foreground_in_seconds,
714 _latest_cms_initial_mark_start_to_end_time_secs,
715 _latest_cms_remark_start_to_end_time_secs,
716 latest_cms_sum_concurrent_phases_time_secs,
717 _latest_cms_ms_marking_start_to_end_time_secs,
718 _latest_cms_ms_end_to_ms_start);
719 }
721 double STW_marking_in_seconds = _latest_cms_initial_mark_start_to_end_time_secs +
722 _latest_cms_remark_start_to_end_time_secs;
723 #ifndef CLOCK_GRANULARITY_TOO_LARGE
724 assert(_latest_cms_ms_marking_start_to_end_time_secs == 0.0 ||
725 latest_cms_sum_concurrent_phases_time_secs == 0.0,
726 "marking done twice?");
727 #endif
728 double ms_time_in_seconds = STW_marking_in_seconds +
729 STW_in_foreground_in_seconds +
730 _latest_cms_ms_marking_start_to_end_time_secs +
731 scaled_concurrent_collection_time();
732 avg_ms_pause()->sample(ms_time_in_seconds);
733 // Use the STW costs from the initial mark and remark plus
734 // the cost of the concurrent phase to calculate a
735 // collection cost.
736 double cost = 0.0;
737 if ((_latest_cms_ms_end_to_ms_start > 0.0) &&
738 (ms_time_in_seconds > 0.0)) {
739 double interval_in_seconds =
740 _latest_cms_ms_end_to_ms_start + ms_time_in_seconds;
742 if (PrintAdaptiveSizePolicy && Verbose) {
743 gclog_or_tty->print_cr("\n ms_time_in_seconds %f "
744 "latest_cms_sum_concurrent_phases_time_secs %f "
745 "interval_in_seconds %f",
746 ms_time_in_seconds,
747 latest_cms_sum_concurrent_phases_time_secs,
748 interval_in_seconds);
749 }
751 cost = collection_cost(ms_time_in_seconds, interval_in_seconds);
753 _avg_ms_gc_cost->sample(cost);
754 // Average this ms cost into all the other types gc costs
755 avg_major_gc_cost()->sample(cost);
757 // Sample for performance counter
758 _avg_ms_interval->sample(interval_in_seconds);
759 }
760 if (PrintAdaptiveSizePolicy && Verbose) {
761 gclog_or_tty->print("cmsAdaptiveSizePolicy::ms_collection_end: "
762 "MS gc cost: %f average: %f", cost, _avg_ms_gc_cost->average());
764 double ms_time_in_ms = ms_time_in_seconds * MILLIUNITS;
765 gclog_or_tty->print_cr(" MS pause: %f (ms) MS period %f (ms)",
766 ms_time_in_ms,
767 _latest_cms_ms_end_to_ms_start * MILLIUNITS);
768 }
769 }
771 // Consider putting this code (here to end) into a
772 // method for convenience.
773 clear_internal_time_intervals();
775 set_first_after_collection();
777 // The concurrent phases keeps track of it's own mutator interval
778 // with this timer. This allows the stop-the-world phase to
779 // be included in the mutator time so that the stop-the-world time
780 // is not double counted. Reset and start it.
781 _concurrent_timer.stop();
782 _concurrent_timer.reset();
783 _concurrent_timer.start();
785 _STW_timer.reset();
786 _STW_timer.start();
787 }
789 void CMSAdaptiveSizePolicy::clear_internal_time_intervals() {
790 _latest_cms_reset_end_to_initial_mark_start_secs = 0.0;
791 _latest_cms_initial_mark_end_to_remark_start_secs = 0.0;
792 _latest_cms_collection_end_to_collection_start_secs = 0.0;
793 _latest_cms_concurrent_marking_time_secs = 0.0;
794 _latest_cms_concurrent_precleaning_time_secs = 0.0;
795 _latest_cms_concurrent_sweeping_time_secs = 0.0;
796 _latest_cms_msc_end_to_msc_start_time_secs = 0.0;
797 _latest_cms_ms_end_to_ms_start = 0.0;
798 _latest_cms_remark_start_to_end_time_secs = 0.0;
799 _latest_cms_initial_mark_start_to_end_time_secs = 0.0;
800 _latest_cms_ms_marking_start_to_end_time_secs = 0.0;
801 }
803 void CMSAdaptiveSizePolicy::clear_generation_free_space_flags() {
804 AdaptiveSizePolicy::clear_generation_free_space_flags();
806 set_change_young_gen_for_maj_pauses(0);
807 }
809 void CMSAdaptiveSizePolicy::concurrent_phases_resume() {
810 if (PrintAdaptiveSizePolicy && Verbose) {
811 gclog_or_tty->stamp();
812 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_phases_resume()");
813 }
814 _concurrent_timer.start();
815 }
817 double CMSAdaptiveSizePolicy::time_since_major_gc() const {
818 _concurrent_timer.stop();
819 double time_since_cms_gc = _concurrent_timer.seconds();
820 _concurrent_timer.start();
821 _STW_timer.stop();
822 double time_since_STW_gc = _STW_timer.seconds();
823 _STW_timer.start();
825 return MIN2(time_since_cms_gc, time_since_STW_gc);
826 }
828 double CMSAdaptiveSizePolicy::major_gc_interval_average_for_decay() const {
829 double cms_interval = _avg_concurrent_interval->average();
830 double msc_interval = _avg_msc_interval->average();
831 double ms_interval = _avg_ms_interval->average();
833 return MAX3(cms_interval, msc_interval, ms_interval);
834 }
836 double CMSAdaptiveSizePolicy::cms_gc_cost() const {
837 return avg_major_gc_cost()->average();
838 }
840 void CMSAdaptiveSizePolicy::ms_collection_marking_begin() {
841 _STW_timer.stop();
842 // Start accumumlating time for the marking in the STW timer.
843 _STW_timer.reset();
844 _STW_timer.start();
845 }
847 void CMSAdaptiveSizePolicy::ms_collection_marking_end(
848 GCCause::Cause gc_cause) {
849 _STW_timer.stop();
850 if (gc_cause != GCCause::_java_lang_system_gc ||
851 UseAdaptiveSizePolicyWithSystemGC) {
852 _latest_cms_ms_marking_start_to_end_time_secs = _STW_timer.seconds();
853 if (PrintAdaptiveSizePolicy && Verbose) {
854 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::"
855 "msc_collection_marking_end: mutator time %f",
856 _latest_cms_ms_marking_start_to_end_time_secs);
857 }
858 }
859 _STW_timer.reset();
860 _STW_timer.start();
861 }
863 double CMSAdaptiveSizePolicy::gc_cost() const {
864 double cms_gen_cost = cms_gc_cost();
865 double result = MIN2(1.0, minor_gc_cost() + cms_gen_cost);
866 assert(result >= 0.0, "Both minor and major costs are non-negative");
867 return result;
868 }
870 // Cost of collection (unit-less)
871 double CMSAdaptiveSizePolicy::collection_cost(double pause_in_seconds,
872 double interval_in_seconds) {
873 // Cost of collection (unit-less)
874 double cost = 0.0;
875 if ((interval_in_seconds > 0.0) &&
876 (pause_in_seconds > 0.0)) {
877 cost =
878 pause_in_seconds / interval_in_seconds;
879 }
880 return cost;
881 }
883 size_t CMSAdaptiveSizePolicy::adjust_eden_for_pause_time(size_t cur_eden) {
884 size_t change = 0;
885 size_t desired_eden = cur_eden;
887 // reduce eden size
888 change = eden_decrement_aligned_down(cur_eden);
889 desired_eden = cur_eden - change;
891 if (PrintAdaptiveSizePolicy && Verbose) {
892 gclog_or_tty->print_cr(
893 "CMSAdaptiveSizePolicy::adjust_eden_for_pause_time "
894 "adjusting eden for pause time. "
895 " starting eden size " SIZE_FORMAT
896 " reduced eden size " SIZE_FORMAT
897 " eden delta " SIZE_FORMAT,
898 cur_eden, desired_eden, change);
899 }
901 return desired_eden;
902 }
904 size_t CMSAdaptiveSizePolicy::adjust_eden_for_throughput(size_t cur_eden) {
906 size_t desired_eden = cur_eden;
908 set_change_young_gen_for_throughput(increase_young_gen_for_througput_true);
910 size_t change = eden_increment_aligned_up(cur_eden);
911 size_t scaled_change = scale_by_gen_gc_cost(change, minor_gc_cost());
913 if (cur_eden + scaled_change > cur_eden) {
914 desired_eden = cur_eden + scaled_change;
915 }
917 _young_gen_change_for_minor_throughput++;
919 if (PrintAdaptiveSizePolicy && Verbose) {
920 gclog_or_tty->print_cr(
921 "CMSAdaptiveSizePolicy::adjust_eden_for_throughput "
922 "adjusting eden for throughput. "
923 " starting eden size " SIZE_FORMAT
924 " increased eden size " SIZE_FORMAT
925 " eden delta " SIZE_FORMAT,
926 cur_eden, desired_eden, scaled_change);
927 }
929 return desired_eden;
930 }
932 size_t CMSAdaptiveSizePolicy::adjust_eden_for_footprint(size_t cur_eden) {
934 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
936 size_t change = eden_decrement(cur_eden);
937 size_t desired_eden_size = cur_eden - change;
939 if (PrintAdaptiveSizePolicy && Verbose) {
940 gclog_or_tty->print_cr(
941 "CMSAdaptiveSizePolicy::adjust_eden_for_footprint "
942 "adjusting eden for footprint. "
943 " starting eden size " SIZE_FORMAT
944 " reduced eden size " SIZE_FORMAT
945 " eden delta " SIZE_FORMAT,
946 cur_eden, desired_eden_size, change);
947 }
948 return desired_eden_size;
949 }
951 // The eden and promo versions should be combined if possible.
952 // They are the same except that the sizes of the decrement
953 // and increment are different for eden and promo.
954 size_t CMSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
955 size_t delta = eden_decrement(cur_eden);
956 return align_size_down(delta, generation_alignment());
957 }
959 size_t CMSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
960 size_t delta = eden_increment(cur_eden);
961 return align_size_up(delta, generation_alignment());
962 }
964 size_t CMSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
965 size_t delta = promo_decrement(cur_promo);
966 return align_size_down(delta, generation_alignment());
967 }
969 size_t CMSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
970 size_t delta = promo_increment(cur_promo);
971 return align_size_up(delta, generation_alignment());
972 }
975 void CMSAdaptiveSizePolicy::compute_eden_space_size(size_t cur_eden,
976 size_t max_eden_size)
977 {
978 size_t desired_eden_size = cur_eden;
979 size_t eden_limit = max_eden_size;
981 // Printout input
982 if (PrintGC && PrintAdaptiveSizePolicy) {
983 gclog_or_tty->print_cr(
984 "CMSAdaptiveSizePolicy::compute_eden_space_size: "
985 "cur_eden " SIZE_FORMAT,
986 cur_eden);
987 }
989 // Used for diagnostics
990 clear_generation_free_space_flags();
992 if (_avg_minor_pause->padded_average() > gc_pause_goal_sec()) {
993 if (minor_pause_young_estimator()->decrement_will_decrease()) {
994 // If the minor pause is too long, shrink the young gen.
995 set_change_young_gen_for_min_pauses(
996 decrease_young_gen_for_min_pauses_true);
997 desired_eden_size = adjust_eden_for_pause_time(desired_eden_size);
998 }
999 } else if ((avg_remark_pause()->padded_average() > gc_pause_goal_sec()) ||
1000 (avg_initial_pause()->padded_average() > gc_pause_goal_sec())) {
1001 // The remark or initial pauses are not meeting the goal. Should
1002 // the generation be shrunk?
1003 if (get_and_clear_first_after_collection() &&
1004 ((avg_remark_pause()->padded_average() > gc_pause_goal_sec() &&
1005 remark_pause_young_estimator()->decrement_will_decrease()) ||
1006 (avg_initial_pause()->padded_average() > gc_pause_goal_sec() &&
1007 initial_pause_young_estimator()->decrement_will_decrease()))) {
1009 set_change_young_gen_for_maj_pauses(
1010 decrease_young_gen_for_maj_pauses_true);
1012 // If the remark or initial pause is too long and this is the
1013 // first young gen collection after a cms collection, shrink
1014 // the young gen.
1015 desired_eden_size = adjust_eden_for_pause_time(desired_eden_size);
1016 }
1017 // If not the first young gen collection after a cms collection,
1018 // don't do anything. In this case an adjustment has already
1019 // been made and the results of the adjustment has not yet been
1020 // measured.
1021 } else if ((minor_gc_cost() >= 0.0) &&
1022 (adjusted_mutator_cost() < _throughput_goal)) {
1023 desired_eden_size = adjust_eden_for_throughput(desired_eden_size);
1024 } else {
1025 desired_eden_size = adjust_eden_for_footprint(desired_eden_size);
1026 }
1028 if (PrintGC && PrintAdaptiveSizePolicy) {
1029 gclog_or_tty->print_cr(
1030 "CMSAdaptiveSizePolicy::compute_eden_space_size limits:"
1031 " desired_eden_size: " SIZE_FORMAT
1032 " old_eden_size: " SIZE_FORMAT,
1033 desired_eden_size, cur_eden);
1034 }
1036 set_eden_size(desired_eden_size);
1037 }
1039 size_t CMSAdaptiveSizePolicy::adjust_promo_for_pause_time(size_t cur_promo) {
1040 size_t change = 0;
1041 size_t desired_promo = cur_promo;
1042 // Move this test up to caller like the adjust_eden_for_pause_time()
1043 // call.
1044 if ((AdaptiveSizePausePolicy == 0) &&
1045 ((avg_remark_pause()->padded_average() > gc_pause_goal_sec()) ||
1046 (avg_initial_pause()->padded_average() > gc_pause_goal_sec()))) {
1047 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
1048 change = promo_decrement_aligned_down(cur_promo);
1049 desired_promo = cur_promo - change;
1050 } else if ((AdaptiveSizePausePolicy > 0) &&
1051 (((avg_remark_pause()->padded_average() > gc_pause_goal_sec()) &&
1052 remark_pause_old_estimator()->decrement_will_decrease()) ||
1053 ((avg_initial_pause()->padded_average() > gc_pause_goal_sec()) &&
1054 initial_pause_old_estimator()->decrement_will_decrease()))) {
1055 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
1056 change = promo_decrement_aligned_down(cur_promo);
1057 desired_promo = cur_promo - change;
1058 }
1060 if ((change != 0) &&PrintAdaptiveSizePolicy && Verbose) {
1061 gclog_or_tty->print_cr(
1062 "CMSAdaptiveSizePolicy::adjust_promo_for_pause_time "
1063 "adjusting promo for pause time. "
1064 " starting promo size " SIZE_FORMAT
1065 " reduced promo size " SIZE_FORMAT
1066 " promo delta " SIZE_FORMAT,
1067 cur_promo, desired_promo, change);
1068 }
1070 return desired_promo;
1071 }
1073 // Try to share this with PS.
1074 size_t CMSAdaptiveSizePolicy::scale_by_gen_gc_cost(size_t base_change,
1075 double gen_gc_cost) {
1077 // Calculate the change to use for the tenured gen.
1078 size_t scaled_change = 0;
1079 // Can the increment to the generation be scaled?
1080 if (gc_cost() >= 0.0 && gen_gc_cost >= 0.0) {
1081 double scale_by_ratio = gen_gc_cost / gc_cost();
1082 scaled_change =
1083 (size_t) (scale_by_ratio * (double) base_change);
1084 if (PrintAdaptiveSizePolicy && Verbose) {
1085 gclog_or_tty->print_cr(
1086 "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
1087 SIZE_FORMAT,
1088 base_change, scale_by_ratio, scaled_change);
1089 }
1090 } else if (gen_gc_cost >= 0.0) {
1091 // Scaling is not going to work. If the major gc time is the
1092 // larger than the other GC costs, give it a full increment.
1093 if (gen_gc_cost >= (gc_cost() - gen_gc_cost)) {
1094 scaled_change = base_change;
1095 }
1096 } else {
1097 // Don't expect to get here but it's ok if it does
1098 // in the product build since the delta will be 0
1099 // and nothing will change.
1100 assert(false, "Unexpected value for gc costs");
1101 }
1103 return scaled_change;
1104 }
1106 size_t CMSAdaptiveSizePolicy::adjust_promo_for_throughput(size_t cur_promo) {
1108 size_t desired_promo = cur_promo;
1110 set_change_old_gen_for_throughput(increase_old_gen_for_throughput_true);
1112 size_t change = promo_increment_aligned_up(cur_promo);
1113 size_t scaled_change = scale_by_gen_gc_cost(change, major_gc_cost());
1115 if (cur_promo + scaled_change > cur_promo) {
1116 desired_promo = cur_promo + scaled_change;
1117 }
1119 _old_gen_change_for_major_throughput++;
1121 if (PrintAdaptiveSizePolicy && Verbose) {
1122 gclog_or_tty->print_cr(
1123 "CMSAdaptiveSizePolicy::adjust_promo_for_throughput "
1124 "adjusting promo for throughput. "
1125 " starting promo size " SIZE_FORMAT
1126 " increased promo size " SIZE_FORMAT
1127 " promo delta " SIZE_FORMAT,
1128 cur_promo, desired_promo, scaled_change);
1129 }
1131 return desired_promo;
1132 }
1134 size_t CMSAdaptiveSizePolicy::adjust_promo_for_footprint(size_t cur_promo,
1135 size_t cur_eden) {
1137 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
1139 size_t change = promo_decrement(cur_promo);
1140 size_t desired_promo_size = cur_promo - change;
1142 if (PrintAdaptiveSizePolicy && Verbose) {
1143 gclog_or_tty->print_cr(
1144 "CMSAdaptiveSizePolicy::adjust_promo_for_footprint "
1145 "adjusting promo for footprint. "
1146 " starting promo size " SIZE_FORMAT
1147 " reduced promo size " SIZE_FORMAT
1148 " promo delta " SIZE_FORMAT,
1149 cur_promo, desired_promo_size, change);
1150 }
1151 return desired_promo_size;
1152 }
1154 void CMSAdaptiveSizePolicy::compute_tenured_generation_free_space(
1155 size_t cur_tenured_free,
1156 size_t max_tenured_available,
1157 size_t cur_eden) {
1158 // This can be bad if the desired value grows/shrinks without
1159 // any connection to the read free space
1160 size_t desired_promo_size = promo_size();
1161 size_t tenured_limit = max_tenured_available;
1163 // Printout input
1164 if (PrintGC && PrintAdaptiveSizePolicy) {
1165 gclog_or_tty->print_cr(
1166 "CMSAdaptiveSizePolicy::compute_tenured_generation_free_space: "
1167 "cur_tenured_free " SIZE_FORMAT
1168 " max_tenured_available " SIZE_FORMAT,
1169 cur_tenured_free, max_tenured_available);
1170 }
1172 // Used for diagnostics
1173 clear_generation_free_space_flags();
1175 set_decide_at_full_gc(decide_at_full_gc_true);
1176 if (avg_remark_pause()->padded_average() > gc_pause_goal_sec() ||
1177 avg_initial_pause()->padded_average() > gc_pause_goal_sec()) {
1178 desired_promo_size = adjust_promo_for_pause_time(cur_tenured_free);
1179 } else if (avg_minor_pause()->padded_average() > gc_pause_goal_sec()) {
1180 // Nothing to do since the minor collections are too large and
1181 // this method only deals with the cms generation.
1182 } else if ((cms_gc_cost() >= 0.0) &&
1183 (adjusted_mutator_cost() < _throughput_goal)) {
1184 desired_promo_size = adjust_promo_for_throughput(cur_tenured_free);
1185 } else {
1186 desired_promo_size = adjust_promo_for_footprint(cur_tenured_free,
1187 cur_eden);
1188 }
1190 if (PrintGC && PrintAdaptiveSizePolicy) {
1191 gclog_or_tty->print_cr(
1192 "CMSAdaptiveSizePolicy::compute_tenured_generation_free_space limits:"
1193 " desired_promo_size: " SIZE_FORMAT
1194 " old_promo_size: " SIZE_FORMAT,
1195 desired_promo_size, cur_tenured_free);
1196 }
1198 set_promo_size(desired_promo_size);
1199 }
1201 uint CMSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
1202 bool is_survivor_overflow,
1203 uint tenuring_threshold,
1204 size_t survivor_limit) {
1205 assert(survivor_limit >= generation_alignment(),
1206 "survivor_limit too small");
1207 assert((size_t)align_size_down(survivor_limit, generation_alignment())
1208 == survivor_limit, "survivor_limit not aligned");
1210 // Change UsePSAdaptiveSurvivorSizePolicy -> UseAdaptiveSurvivorSizePolicy?
1211 if (!UsePSAdaptiveSurvivorSizePolicy ||
1212 !young_gen_policy_is_ready()) {
1213 return tenuring_threshold;
1214 }
1216 // We'll decide whether to increase or decrease the tenuring
1217 // threshold based partly on the newly computed survivor size
1218 // (if we hit the maximum limit allowed, we'll always choose to
1219 // decrement the threshold).
1220 bool incr_tenuring_threshold = false;
1221 bool decr_tenuring_threshold = false;
1223 set_decrement_tenuring_threshold_for_gc_cost(false);
1224 set_increment_tenuring_threshold_for_gc_cost(false);
1225 set_decrement_tenuring_threshold_for_survivor_limit(false);
1227 if (!is_survivor_overflow) {
1228 // Keep running averages on how much survived
1230 // We use the tenuring threshold to equalize the cost of major
1231 // and minor collections.
1232 // ThresholdTolerance is used to indicate how sensitive the
1233 // tenuring threshold is to differences in cost betweent the
1234 // collection types.
1236 // Get the times of interest. This involves a little work, so
1237 // we cache the values here.
1238 const double major_cost = major_gc_cost();
1239 const double minor_cost = minor_gc_cost();
1241 if (minor_cost > major_cost * _threshold_tolerance_percent) {
1242 // Minor times are getting too long; lower the threshold so
1243 // less survives and more is promoted.
1244 decr_tenuring_threshold = true;
1245 set_decrement_tenuring_threshold_for_gc_cost(true);
1246 } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
1247 // Major times are too long, so we want less promotion.
1248 incr_tenuring_threshold = true;
1249 set_increment_tenuring_threshold_for_gc_cost(true);
1250 }
1252 } else {
1253 // Survivor space overflow occurred, so promoted and survived are
1254 // not accurate. We'll make our best guess by combining survived
1255 // and promoted and count them as survivors.
1256 //
1257 // We'll lower the tenuring threshold to see if we can correct
1258 // things. Also, set the survivor size conservatively. We're
1259 // trying to avoid many overflows from occurring if defnew size
1260 // is just too small.
1262 decr_tenuring_threshold = true;
1263 }
1265 // The padded average also maintains a deviation from the average;
1266 // we use this to see how good of an estimate we have of what survived.
1267 // We're trying to pad the survivor size as little as possible without
1268 // overflowing the survivor spaces.
1269 size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
1270 generation_alignment());
1271 target_size = MAX2(target_size, generation_alignment());
1273 if (target_size > survivor_limit) {
1274 // Target size is bigger than we can handle. Let's also reduce
1275 // the tenuring threshold.
1276 target_size = survivor_limit;
1277 decr_tenuring_threshold = true;
1278 set_decrement_tenuring_threshold_for_survivor_limit(true);
1279 }
1281 // Finally, increment or decrement the tenuring threshold, as decided above.
1282 // We test for decrementing first, as we might have hit the target size
1283 // limit.
1284 if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1285 if (tenuring_threshold > 1) {
1286 tenuring_threshold--;
1287 }
1288 } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1289 if (tenuring_threshold < MaxTenuringThreshold) {
1290 tenuring_threshold++;
1291 }
1292 }
1294 // We keep a running average of the amount promoted which is used
1295 // to decide when we should collect the old generation (when
1296 // the amount of old gen free space is less than what we expect to
1297 // promote).
1299 if (PrintAdaptiveSizePolicy) {
1300 // A little more detail if Verbose is on
1301 GenCollectedHeap* gch = GenCollectedHeap::heap();
1302 if (Verbose) {
1303 gclog_or_tty->print( " avg_survived: %f"
1304 " avg_deviation: %f",
1305 _avg_survived->average(),
1306 _avg_survived->deviation());
1307 }
1309 gclog_or_tty->print( " avg_survived_padded_avg: %f",
1310 _avg_survived->padded_average());
1312 if (Verbose) {
1313 gclog_or_tty->print( " avg_promoted_avg: %f"
1314 " avg_promoted_dev: %f",
1315 gch->gc_stats(1)->avg_promoted()->average(),
1316 gch->gc_stats(1)->avg_promoted()->deviation());
1317 }
1319 gclog_or_tty->print( " avg_promoted_padded_avg: %f"
1320 " avg_pretenured_padded_avg: %f"
1321 " tenuring_thresh: %u"
1322 " target_size: " SIZE_FORMAT
1323 " survivor_limit: " SIZE_FORMAT,
1324 gch->gc_stats(1)->avg_promoted()->padded_average(),
1325 _avg_pretenured->padded_average(),
1326 tenuring_threshold, target_size, survivor_limit);
1327 gclog_or_tty->cr();
1328 }
1330 set_survivor_size(target_size);
1332 return tenuring_threshold;
1333 }
1335 bool CMSAdaptiveSizePolicy::get_and_clear_first_after_collection() {
1336 bool result = _first_after_collection;
1337 _first_after_collection = false;
1338 return result;
1339 }
1341 bool CMSAdaptiveSizePolicy::print_adaptive_size_policy_on(
1342 outputStream* st) const {
1344 if (!UseAdaptiveSizePolicy) return false;
1346 GenCollectedHeap* gch = GenCollectedHeap::heap();
1347 Generation* gen0 = gch->get_gen(0);
1348 DefNewGeneration* def_new = gen0->as_DefNewGeneration();
1349 return
1350 AdaptiveSizePolicy::print_adaptive_size_policy_on(
1351 st,
1352 def_new->tenuring_threshold());
1353 }
