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src/share/vm/gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.cpp@685df3c6f84b
src/share/vm/gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.cpp
Tue, 18 Sep 2012 23:35:42 -0700
- author
- jmasa
- date
- Tue, 18 Sep 2012 23:35:42 -0700
- changeset 4196
- 685df3c6f84b
- parent 4129
- 22b8d3d181d9
- child 5192
- 14d3f71f831d
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7045397: NPG: Add freelists to class loader arenas.
Reviewed-by: coleenp, stefank, jprovino, ohair
1 /*
2 * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
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_bsd
41 # include "os_bsd.inline.hpp"
42 #endif
43 elapsedTimer CMSAdaptiveSizePolicy::_concurrent_timer;
44 elapsedTimer CMSAdaptiveSizePolicy::_STW_timer;
46 // Defined if the granularity of the time measurements is potentially too large.
47 #define CLOCK_GRANULARITY_TOO_LARGE
49 CMSAdaptiveSizePolicy::CMSAdaptiveSizePolicy(size_t init_eden_size,
50 size_t init_promo_size,
51 size_t init_survivor_size,
52 double max_gc_minor_pause_sec,
53 double max_gc_pause_sec,
54 uint gc_cost_ratio) :
55 AdaptiveSizePolicy(init_eden_size,
56 init_promo_size,
57 init_survivor_size,
58 max_gc_pause_sec,
59 gc_cost_ratio) {
61 clear_internal_time_intervals();
63 _processor_count = os::active_processor_count();
65 if (CMSConcurrentMTEnabled && (ConcGCThreads > 1)) {
66 assert(_processor_count > 0, "Processor count is suspect");
67 _concurrent_processor_count = MIN2((uint) ConcGCThreads,
68 (uint) _processor_count);
69 } else {
70 _concurrent_processor_count = 1;
71 }
73 _avg_concurrent_time = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
74 _avg_concurrent_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
75 _avg_concurrent_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
77 _avg_initial_pause = new AdaptivePaddedAverage(AdaptiveTimeWeight,
78 PausePadding);
79 _avg_remark_pause = new AdaptivePaddedAverage(AdaptiveTimeWeight,
80 PausePadding);
82 _avg_cms_STW_time = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
83 _avg_cms_STW_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
85 _avg_cms_free = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
86 _avg_cms_free_at_sweep = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
87 _avg_cms_promo = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
89 // Mark-sweep-compact
90 _avg_msc_pause = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
91 _avg_msc_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
92 _avg_msc_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
94 // Mark-sweep
95 _avg_ms_pause = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
96 _avg_ms_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
97 _avg_ms_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
99 // Variables that estimate pause times as a function of generation
100 // size.
101 _remark_pause_old_estimator =
102 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
103 _initial_pause_old_estimator =
104 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
105 _remark_pause_young_estimator =
106 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
107 _initial_pause_young_estimator =
108 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
110 // Alignment comes from that used in ReservedSpace.
111 _generation_alignment = os::vm_allocation_granularity();
113 // Start the concurrent timer here so that the first
114 // concurrent_phases_begin() measures a finite mutator
115 // time. A finite mutator time is used to determine
116 // if a concurrent collection has been started. If this
117 // proves to be a problem, use some explicit flag to
118 // signal that a concurrent collection has been started.
119 _concurrent_timer.start();
120 _STW_timer.start();
121 }
123 double CMSAdaptiveSizePolicy::concurrent_processor_fraction() {
124 // For now assume no other daemon threads are taking alway
125 // cpu's from the application.
126 return ((double) _concurrent_processor_count / (double) _processor_count);
127 }
129 double CMSAdaptiveSizePolicy::concurrent_collection_cost(
130 double interval_in_seconds) {
131 // When the precleaning and sweeping phases use multiple
132 // threads, change one_processor_fraction to
133 // concurrent_processor_fraction().
134 double one_processor_fraction = 1.0 / ((double) processor_count());
135 double concurrent_cost =
136 collection_cost(_latest_cms_concurrent_marking_time_secs,
137 interval_in_seconds) * concurrent_processor_fraction() +
138 collection_cost(_latest_cms_concurrent_precleaning_time_secs,
139 interval_in_seconds) * one_processor_fraction +
140 collection_cost(_latest_cms_concurrent_sweeping_time_secs,
141 interval_in_seconds) * one_processor_fraction;
142 if (PrintAdaptiveSizePolicy && Verbose) {
143 gclog_or_tty->print_cr(
144 "\nCMSAdaptiveSizePolicy::scaled_concurrent_collection_cost(%f) "
145 "_latest_cms_concurrent_marking_cost %f "
146 "_latest_cms_concurrent_precleaning_cost %f "
147 "_latest_cms_concurrent_sweeping_cost %f "
148 "concurrent_processor_fraction %f "
149 "concurrent_cost %f ",
150 interval_in_seconds,
151 collection_cost(_latest_cms_concurrent_marking_time_secs,
152 interval_in_seconds),
153 collection_cost(_latest_cms_concurrent_precleaning_time_secs,
154 interval_in_seconds),
155 collection_cost(_latest_cms_concurrent_sweeping_time_secs,
156 interval_in_seconds),
157 concurrent_processor_fraction(),
158 concurrent_cost);
159 }
160 return concurrent_cost;
161 }
163 double CMSAdaptiveSizePolicy::concurrent_collection_time() {
164 double latest_cms_sum_concurrent_phases_time_secs =
165 _latest_cms_concurrent_marking_time_secs +
166 _latest_cms_concurrent_precleaning_time_secs +
167 _latest_cms_concurrent_sweeping_time_secs;
168 return latest_cms_sum_concurrent_phases_time_secs;
169 }
171 double CMSAdaptiveSizePolicy::scaled_concurrent_collection_time() {
172 // When the precleaning and sweeping phases use multiple
173 // threads, change one_processor_fraction to
174 // concurrent_processor_fraction().
175 double one_processor_fraction = 1.0 / ((double) processor_count());
176 double latest_cms_sum_concurrent_phases_time_secs =
177 _latest_cms_concurrent_marking_time_secs * concurrent_processor_fraction() +
178 _latest_cms_concurrent_precleaning_time_secs * one_processor_fraction +
179 _latest_cms_concurrent_sweeping_time_secs * one_processor_fraction ;
180 if (PrintAdaptiveSizePolicy && Verbose) {
181 gclog_or_tty->print_cr(
182 "\nCMSAdaptiveSizePolicy::scaled_concurrent_collection_time "
183 "_latest_cms_concurrent_marking_time_secs %f "
184 "_latest_cms_concurrent_precleaning_time_secs %f "
185 "_latest_cms_concurrent_sweeping_time_secs %f "
186 "concurrent_processor_fraction %f "
187 "latest_cms_sum_concurrent_phases_time_secs %f ",
188 _latest_cms_concurrent_marking_time_secs,
189 _latest_cms_concurrent_precleaning_time_secs,
190 _latest_cms_concurrent_sweeping_time_secs,
191 concurrent_processor_fraction(),
192 latest_cms_sum_concurrent_phases_time_secs);
193 }
194 return latest_cms_sum_concurrent_phases_time_secs;
195 }
197 void CMSAdaptiveSizePolicy::update_minor_pause_old_estimator(
198 double minor_pause_in_ms) {
199 // Get the equivalent of the free space
200 // that is available for promotions in the CMS generation
201 // and use that to update _minor_pause_old_estimator
203 // Don't implement this until it is needed. A warning is
204 // printed if _minor_pause_old_estimator is used.
205 }
207 void CMSAdaptiveSizePolicy::concurrent_marking_begin() {
208 if (PrintAdaptiveSizePolicy && Verbose) {
209 gclog_or_tty->print(" ");
210 gclog_or_tty->stamp();
211 gclog_or_tty->print(": concurrent_marking_begin ");
212 }
213 // Update the interval time
214 _concurrent_timer.stop();
215 _latest_cms_collection_end_to_collection_start_secs = _concurrent_timer.seconds();
216 if (PrintAdaptiveSizePolicy && Verbose) {
217 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_marking_begin: "
218 "mutator time %f", _latest_cms_collection_end_to_collection_start_secs);
219 }
220 _concurrent_timer.reset();
221 _concurrent_timer.start();
222 }
224 void CMSAdaptiveSizePolicy::concurrent_marking_end() {
225 if (PrintAdaptiveSizePolicy && Verbose) {
226 gclog_or_tty->stamp();
227 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_marking_end()");
228 }
230 _concurrent_timer.stop();
231 _latest_cms_concurrent_marking_time_secs = _concurrent_timer.seconds();
233 if (PrintAdaptiveSizePolicy && Verbose) {
234 gclog_or_tty->print_cr("\n CMSAdaptiveSizePolicy::concurrent_marking_end"
235 ":concurrent marking time (s) %f",
236 _latest_cms_concurrent_marking_time_secs);
237 }
238 }
240 void CMSAdaptiveSizePolicy::concurrent_precleaning_begin() {
241 if (PrintAdaptiveSizePolicy && Verbose) {
242 gclog_or_tty->stamp();
243 gclog_or_tty->print_cr(
244 "CMSAdaptiveSizePolicy::concurrent_precleaning_begin()");
245 }
246 _concurrent_timer.reset();
247 _concurrent_timer.start();
248 }
251 void CMSAdaptiveSizePolicy::concurrent_precleaning_end() {
252 if (PrintAdaptiveSizePolicy && Verbose) {
253 gclog_or_tty->stamp();
254 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_precleaning_end()");
255 }
257 _concurrent_timer.stop();
258 // May be set again by a second call during the same collection.
259 _latest_cms_concurrent_precleaning_time_secs = _concurrent_timer.seconds();
261 if (PrintAdaptiveSizePolicy && Verbose) {
262 gclog_or_tty->print_cr("\n CMSAdaptiveSizePolicy::concurrent_precleaning_end"
263 ":concurrent precleaning time (s) %f",
264 _latest_cms_concurrent_precleaning_time_secs);
265 }
266 }
268 void CMSAdaptiveSizePolicy::concurrent_sweeping_begin() {
269 if (PrintAdaptiveSizePolicy && Verbose) {
270 gclog_or_tty->stamp();
271 gclog_or_tty->print_cr(
272 "CMSAdaptiveSizePolicy::concurrent_sweeping_begin()");
273 }
274 _concurrent_timer.reset();
275 _concurrent_timer.start();
276 }
279 void CMSAdaptiveSizePolicy::concurrent_sweeping_end() {
280 if (PrintAdaptiveSizePolicy && Verbose) {
281 gclog_or_tty->stamp();
282 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_sweeping_end()");
283 }
285 _concurrent_timer.stop();
286 _latest_cms_concurrent_sweeping_time_secs = _concurrent_timer.seconds();
288 if (PrintAdaptiveSizePolicy && Verbose) {
289 gclog_or_tty->print_cr("\n CMSAdaptiveSizePolicy::concurrent_sweeping_end"
290 ":concurrent sweeping time (s) %f",
291 _latest_cms_concurrent_sweeping_time_secs);
292 }
293 }
295 void CMSAdaptiveSizePolicy::concurrent_phases_end(GCCause::Cause gc_cause,
296 size_t cur_eden,
297 size_t cur_promo) {
298 if (PrintAdaptiveSizePolicy && Verbose) {
299 gclog_or_tty->print(" ");
300 gclog_or_tty->stamp();
301 gclog_or_tty->print(": concurrent_phases_end ");
302 }
304 // Update the concurrent timer
305 _concurrent_timer.stop();
307 if (gc_cause != GCCause::_java_lang_system_gc ||
308 UseAdaptiveSizePolicyWithSystemGC) {
310 avg_cms_free()->sample(cur_promo);
311 double latest_cms_sum_concurrent_phases_time_secs =
312 concurrent_collection_time();
314 _avg_concurrent_time->sample(latest_cms_sum_concurrent_phases_time_secs);
316 // Cost of collection (unit-less)
318 // Total interval for collection. May not be valid. Tests
319 // below determine whether to use this.
320 //
321 if (PrintAdaptiveSizePolicy && Verbose) {
322 gclog_or_tty->print_cr("\nCMSAdaptiveSizePolicy::concurrent_phases_end \n"
323 "_latest_cms_reset_end_to_initial_mark_start_secs %f \n"
324 "_latest_cms_initial_mark_start_to_end_time_secs %f \n"
325 "_latest_cms_remark_start_to_end_time_secs %f \n"
326 "_latest_cms_concurrent_marking_time_secs %f \n"
327 "_latest_cms_concurrent_precleaning_time_secs %f \n"
328 "_latest_cms_concurrent_sweeping_time_secs %f \n"
329 "latest_cms_sum_concurrent_phases_time_secs %f \n"
330 "_latest_cms_collection_end_to_collection_start_secs %f \n"
331 "concurrent_processor_fraction %f",
332 _latest_cms_reset_end_to_initial_mark_start_secs,
333 _latest_cms_initial_mark_start_to_end_time_secs,
334 _latest_cms_remark_start_to_end_time_secs,
335 _latest_cms_concurrent_marking_time_secs,
336 _latest_cms_concurrent_precleaning_time_secs,
337 _latest_cms_concurrent_sweeping_time_secs,
338 latest_cms_sum_concurrent_phases_time_secs,
339 _latest_cms_collection_end_to_collection_start_secs,
340 concurrent_processor_fraction());
341 }
342 double interval_in_seconds =
343 _latest_cms_initial_mark_start_to_end_time_secs +
344 _latest_cms_remark_start_to_end_time_secs +
345 latest_cms_sum_concurrent_phases_time_secs +
346 _latest_cms_collection_end_to_collection_start_secs;
347 assert(interval_in_seconds >= 0.0,
348 "Bad interval between cms collections");
350 // Sample for performance counter
351 avg_concurrent_interval()->sample(interval_in_seconds);
353 // STW costs (initial and remark pauses)
354 // Cost of collection (unit-less)
355 assert(_latest_cms_initial_mark_start_to_end_time_secs >= 0.0,
356 "Bad initial mark pause");
357 assert(_latest_cms_remark_start_to_end_time_secs >= 0.0,
358 "Bad remark pause");
359 double STW_time_in_seconds =
360 _latest_cms_initial_mark_start_to_end_time_secs +
361 _latest_cms_remark_start_to_end_time_secs;
362 double STW_collection_cost = 0.0;
363 if (interval_in_seconds > 0.0) {
364 // cost for the STW phases of the concurrent collection.
365 STW_collection_cost = STW_time_in_seconds / interval_in_seconds;
366 avg_cms_STW_gc_cost()->sample(STW_collection_cost);
367 }
368 if (PrintAdaptiveSizePolicy && Verbose) {
369 gclog_or_tty->print("cmsAdaptiveSizePolicy::STW_collection_end: "
370 "STW gc cost: %f average: %f", STW_collection_cost,
371 avg_cms_STW_gc_cost()->average());
372 gclog_or_tty->print_cr(" STW pause: %f (ms) STW period %f (ms)",
373 (double) STW_time_in_seconds * MILLIUNITS,
374 (double) interval_in_seconds * MILLIUNITS);
375 }
377 double concurrent_cost = 0.0;
378 if (latest_cms_sum_concurrent_phases_time_secs > 0.0) {
379 concurrent_cost = concurrent_collection_cost(interval_in_seconds);
381 avg_concurrent_gc_cost()->sample(concurrent_cost);
382 // Average this ms cost into all the other types gc costs
384 if (PrintAdaptiveSizePolicy && Verbose) {
385 gclog_or_tty->print("cmsAdaptiveSizePolicy::concurrent_phases_end: "
386 "concurrent gc cost: %f average: %f",
387 concurrent_cost,
388 _avg_concurrent_gc_cost->average());
389 gclog_or_tty->print_cr(" concurrent time: %f (ms) cms period %f (ms)"
390 " processor fraction: %f",
391 latest_cms_sum_concurrent_phases_time_secs * MILLIUNITS,
392 interval_in_seconds * MILLIUNITS,
393 concurrent_processor_fraction());
394 }
395 }
396 double total_collection_cost = STW_collection_cost + concurrent_cost;
397 avg_major_gc_cost()->sample(total_collection_cost);
399 // Gather information for estimating future behavior
400 double initial_pause_in_ms = _latest_cms_initial_mark_start_to_end_time_secs * MILLIUNITS;
401 double remark_pause_in_ms = _latest_cms_remark_start_to_end_time_secs * MILLIUNITS;
403 double cur_promo_size_in_mbytes = ((double)cur_promo)/((double)M);
404 initial_pause_old_estimator()->update(cur_promo_size_in_mbytes,
405 initial_pause_in_ms);
406 remark_pause_old_estimator()->update(cur_promo_size_in_mbytes,
407 remark_pause_in_ms);
408 major_collection_estimator()->update(cur_promo_size_in_mbytes,
409 total_collection_cost);
411 // This estimate uses the average eden size. It could also
412 // have used the latest eden size. Which is better?
413 double cur_eden_size_in_mbytes = ((double)cur_eden)/((double) M);
414 initial_pause_young_estimator()->update(cur_eden_size_in_mbytes,
415 initial_pause_in_ms);
416 remark_pause_young_estimator()->update(cur_eden_size_in_mbytes,
417 remark_pause_in_ms);
418 }
420 clear_internal_time_intervals();
422 set_first_after_collection();
424 // The concurrent phases keeps track of it's own mutator interval
425 // with this timer. This allows the stop-the-world phase to
426 // be included in the mutator time so that the stop-the-world time
427 // is not double counted. Reset and start it.
428 _concurrent_timer.reset();
429 _concurrent_timer.start();
431 // The mutator time between STW phases does not include the
432 // concurrent collection time.
433 _STW_timer.reset();
434 _STW_timer.start();
435 }
437 void CMSAdaptiveSizePolicy::checkpoint_roots_initial_begin() {
438 // Update the interval time
439 _STW_timer.stop();
440 _latest_cms_reset_end_to_initial_mark_start_secs = _STW_timer.seconds();
441 // Reset for the initial mark
442 _STW_timer.reset();
443 _STW_timer.start();
444 }
446 void CMSAdaptiveSizePolicy::checkpoint_roots_initial_end(
447 GCCause::Cause gc_cause) {
448 _STW_timer.stop();
450 if (gc_cause != GCCause::_java_lang_system_gc ||
451 UseAdaptiveSizePolicyWithSystemGC) {
452 _latest_cms_initial_mark_start_to_end_time_secs = _STW_timer.seconds();
453 avg_initial_pause()->sample(_latest_cms_initial_mark_start_to_end_time_secs);
455 if (PrintAdaptiveSizePolicy && Verbose) {
456 gclog_or_tty->print(
457 "cmsAdaptiveSizePolicy::checkpoint_roots_initial_end: "
458 "initial pause: %f ", _latest_cms_initial_mark_start_to_end_time_secs);
459 }
460 }
462 _STW_timer.reset();
463 _STW_timer.start();
464 }
466 void CMSAdaptiveSizePolicy::checkpoint_roots_final_begin() {
467 _STW_timer.stop();
468 _latest_cms_initial_mark_end_to_remark_start_secs = _STW_timer.seconds();
469 // Start accumumlating time for the remark in the STW timer.
470 _STW_timer.reset();
471 _STW_timer.start();
472 }
474 void CMSAdaptiveSizePolicy::checkpoint_roots_final_end(
475 GCCause::Cause gc_cause) {
476 _STW_timer.stop();
477 if (gc_cause != GCCause::_java_lang_system_gc ||
478 UseAdaptiveSizePolicyWithSystemGC) {
479 // Total initial mark pause + remark pause.
480 _latest_cms_remark_start_to_end_time_secs = _STW_timer.seconds();
481 double STW_time_in_seconds = _latest_cms_initial_mark_start_to_end_time_secs +
482 _latest_cms_remark_start_to_end_time_secs;
483 double STW_time_in_ms = STW_time_in_seconds * MILLIUNITS;
485 avg_remark_pause()->sample(_latest_cms_remark_start_to_end_time_secs);
487 // Sample total for initial mark + remark
488 avg_cms_STW_time()->sample(STW_time_in_seconds);
490 if (PrintAdaptiveSizePolicy && Verbose) {
491 gclog_or_tty->print("cmsAdaptiveSizePolicy::checkpoint_roots_final_end: "
492 "remark pause: %f", _latest_cms_remark_start_to_end_time_secs);
493 }
495 }
496 // Don't start the STW times here because the concurrent
497 // sweep and reset has not happened.
498 // Keep the old comment above in case I don't understand
499 // what is going on but now
500 // Start the STW timer because it is used by ms_collection_begin()
501 // and ms_collection_end() to get the sweep time if a MS is being
502 // done in the foreground.
503 _STW_timer.reset();
504 _STW_timer.start();
505 }
507 void CMSAdaptiveSizePolicy::msc_collection_begin() {
508 if (PrintAdaptiveSizePolicy && Verbose) {
509 gclog_or_tty->print(" ");
510 gclog_or_tty->stamp();
511 gclog_or_tty->print(": msc_collection_begin ");
512 }
513 _STW_timer.stop();
514 _latest_cms_msc_end_to_msc_start_time_secs = _STW_timer.seconds();
515 if (PrintAdaptiveSizePolicy && Verbose) {
516 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::msc_collection_begin: "
517 "mutator time %f",
518 _latest_cms_msc_end_to_msc_start_time_secs);
519 }
520 avg_msc_interval()->sample(_latest_cms_msc_end_to_msc_start_time_secs);
521 _STW_timer.reset();
522 _STW_timer.start();
523 }
525 void CMSAdaptiveSizePolicy::msc_collection_end(GCCause::Cause gc_cause) {
526 if (PrintAdaptiveSizePolicy && Verbose) {
527 gclog_or_tty->print(" ");
528 gclog_or_tty->stamp();
529 gclog_or_tty->print(": msc_collection_end ");
530 }
531 _STW_timer.stop();
532 if (gc_cause != GCCause::_java_lang_system_gc ||
533 UseAdaptiveSizePolicyWithSystemGC) {
534 double msc_pause_in_seconds = _STW_timer.seconds();
535 if ((_latest_cms_msc_end_to_msc_start_time_secs > 0.0) &&
536 (msc_pause_in_seconds > 0.0)) {
537 avg_msc_pause()->sample(msc_pause_in_seconds);
538 double mutator_time_in_seconds = 0.0;
539 if (_latest_cms_collection_end_to_collection_start_secs == 0.0) {
540 // This assertion may fail because of time stamp gradularity.
541 // Comment it out and investiage it at a later time. The large
542 // time stamp granularity occurs on some older linux systems.
543 #ifndef CLOCK_GRANULARITY_TOO_LARGE
544 assert((_latest_cms_concurrent_marking_time_secs == 0.0) &&
545 (_latest_cms_concurrent_precleaning_time_secs == 0.0) &&
546 (_latest_cms_concurrent_sweeping_time_secs == 0.0),
547 "There should not be any concurrent time");
548 #endif
549 // A concurrent collection did not start. Mutator time
550 // between collections comes from the STW MSC timer.
551 mutator_time_in_seconds = _latest_cms_msc_end_to_msc_start_time_secs;
552 } else {
553 // The concurrent collection did start so count the mutator
554 // time to the start of the concurrent collection. In this
555 // case the _latest_cms_msc_end_to_msc_start_time_secs measures
556 // the time between the initial mark or remark and the
557 // start of the MSC. That has no real meaning.
558 mutator_time_in_seconds = _latest_cms_collection_end_to_collection_start_secs;
559 }
561 double latest_cms_sum_concurrent_phases_time_secs =
562 concurrent_collection_time();
563 double interval_in_seconds =
564 mutator_time_in_seconds +
565 _latest_cms_initial_mark_start_to_end_time_secs +
566 _latest_cms_remark_start_to_end_time_secs +
567 latest_cms_sum_concurrent_phases_time_secs +
568 msc_pause_in_seconds;
570 if (PrintAdaptiveSizePolicy && Verbose) {
571 gclog_or_tty->print_cr(" interval_in_seconds %f \n"
572 " mutator_time_in_seconds %f \n"
573 " _latest_cms_initial_mark_start_to_end_time_secs %f\n"
574 " _latest_cms_remark_start_to_end_time_secs %f\n"
575 " latest_cms_sum_concurrent_phases_time_secs %f\n"
576 " msc_pause_in_seconds %f\n",
577 interval_in_seconds,
578 mutator_time_in_seconds,
579 _latest_cms_initial_mark_start_to_end_time_secs,
580 _latest_cms_remark_start_to_end_time_secs,
581 latest_cms_sum_concurrent_phases_time_secs,
582 msc_pause_in_seconds);
583 }
585 // The concurrent cost is wasted cost but it should be
586 // included.
587 double concurrent_cost = concurrent_collection_cost(interval_in_seconds);
589 // Initial mark and remark, also wasted.
590 double STW_time_in_seconds = _latest_cms_initial_mark_start_to_end_time_secs +
591 _latest_cms_remark_start_to_end_time_secs;
592 double STW_collection_cost =
593 collection_cost(STW_time_in_seconds, interval_in_seconds) +
594 concurrent_cost;
596 if (PrintAdaptiveSizePolicy && Verbose) {
597 gclog_or_tty->print_cr(" msc_collection_end:\n"
598 "_latest_cms_collection_end_to_collection_start_secs %f\n"
599 "_latest_cms_msc_end_to_msc_start_time_secs %f\n"
600 "_latest_cms_initial_mark_start_to_end_time_secs %f\n"
601 "_latest_cms_remark_start_to_end_time_secs %f\n"
602 "latest_cms_sum_concurrent_phases_time_secs %f\n",
603 _latest_cms_collection_end_to_collection_start_secs,
604 _latest_cms_msc_end_to_msc_start_time_secs,
605 _latest_cms_initial_mark_start_to_end_time_secs,
606 _latest_cms_remark_start_to_end_time_secs,
607 latest_cms_sum_concurrent_phases_time_secs);
609 gclog_or_tty->print_cr(" msc_collection_end: \n"
610 "latest_cms_sum_concurrent_phases_time_secs %f\n"
611 "STW_time_in_seconds %f\n"
612 "msc_pause_in_seconds %f\n",
613 latest_cms_sum_concurrent_phases_time_secs,
614 STW_time_in_seconds,
615 msc_pause_in_seconds);
616 }
618 double cost = concurrent_cost + STW_collection_cost +
619 collection_cost(msc_pause_in_seconds, interval_in_seconds);
621 _avg_msc_gc_cost->sample(cost);
623 // Average this ms cost into all the other types gc costs
624 avg_major_gc_cost()->sample(cost);
626 // Sample for performance counter
627 _avg_msc_interval->sample(interval_in_seconds);
628 if (PrintAdaptiveSizePolicy && Verbose) {
629 gclog_or_tty->print("cmsAdaptiveSizePolicy::msc_collection_end: "
630 "MSC gc cost: %f average: %f", cost,
631 _avg_msc_gc_cost->average());
633 double msc_pause_in_ms = msc_pause_in_seconds * MILLIUNITS;
634 gclog_or_tty->print_cr(" MSC pause: %f (ms) MSC period %f (ms)",
635 msc_pause_in_ms, (double) interval_in_seconds * MILLIUNITS);
636 }
637 }
638 }
640 clear_internal_time_intervals();
642 // Can this call be put into the epilogue?
643 set_first_after_collection();
645 // The concurrent phases keeps track of it's own mutator interval
646 // with this timer. This allows the stop-the-world phase to
647 // be included in the mutator time so that the stop-the-world time
648 // is not double counted. Reset and start it.
649 _concurrent_timer.stop();
650 _concurrent_timer.reset();
651 _concurrent_timer.start();
653 _STW_timer.reset();
654 _STW_timer.start();
655 }
657 void CMSAdaptiveSizePolicy::ms_collection_begin() {
658 if (PrintAdaptiveSizePolicy && Verbose) {
659 gclog_or_tty->print(" ");
660 gclog_or_tty->stamp();
661 gclog_or_tty->print(": ms_collection_begin ");
662 }
663 _STW_timer.stop();
664 _latest_cms_ms_end_to_ms_start = _STW_timer.seconds();
665 if (PrintAdaptiveSizePolicy && Verbose) {
666 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::ms_collection_begin: "
667 "mutator time %f",
668 _latest_cms_ms_end_to_ms_start);
669 }
670 avg_ms_interval()->sample(_STW_timer.seconds());
671 _STW_timer.reset();
672 _STW_timer.start();
673 }
675 void CMSAdaptiveSizePolicy::ms_collection_end(GCCause::Cause gc_cause) {
676 if (PrintAdaptiveSizePolicy && Verbose) {
677 gclog_or_tty->print(" ");
678 gclog_or_tty->stamp();
679 gclog_or_tty->print(": ms_collection_end ");
680 }
681 _STW_timer.stop();
682 if (gc_cause != GCCause::_java_lang_system_gc ||
683 UseAdaptiveSizePolicyWithSystemGC) {
684 // The MS collection is a foreground collection that does all
685 // the parts of a mostly concurrent collection.
686 //
687 // For this collection include the cost of the
688 // initial mark
689 // remark
690 // all concurrent time (scaled down by the
691 // concurrent_processor_fraction). Some
692 // may be zero if the baton was passed before
693 // it was reached.
694 // concurrent marking
695 // sweeping
696 // resetting
697 // STW after baton was passed (STW_in_foreground_in_seconds)
698 double STW_in_foreground_in_seconds = _STW_timer.seconds();
700 double latest_cms_sum_concurrent_phases_time_secs =
701 concurrent_collection_time();
702 if (PrintAdaptiveSizePolicy && Verbose) {
703 gclog_or_tty->print_cr("\nCMSAdaptiveSizePolicy::ms_collecton_end "
704 "STW_in_foreground_in_seconds %f "
705 "_latest_cms_initial_mark_start_to_end_time_secs %f "
706 "_latest_cms_remark_start_to_end_time_secs %f "
707 "latest_cms_sum_concurrent_phases_time_secs %f "
708 "_latest_cms_ms_marking_start_to_end_time_secs %f "
709 "_latest_cms_ms_end_to_ms_start %f",
710 STW_in_foreground_in_seconds,
711 _latest_cms_initial_mark_start_to_end_time_secs,
712 _latest_cms_remark_start_to_end_time_secs,
713 latest_cms_sum_concurrent_phases_time_secs,
714 _latest_cms_ms_marking_start_to_end_time_secs,
715 _latest_cms_ms_end_to_ms_start);
716 }
718 double STW_marking_in_seconds = _latest_cms_initial_mark_start_to_end_time_secs +
719 _latest_cms_remark_start_to_end_time_secs;
720 #ifndef CLOCK_GRANULARITY_TOO_LARGE
721 assert(_latest_cms_ms_marking_start_to_end_time_secs == 0.0 ||
722 latest_cms_sum_concurrent_phases_time_secs == 0.0,
723 "marking done twice?");
724 #endif
725 double ms_time_in_seconds = STW_marking_in_seconds +
726 STW_in_foreground_in_seconds +
727 _latest_cms_ms_marking_start_to_end_time_secs +
728 scaled_concurrent_collection_time();
729 avg_ms_pause()->sample(ms_time_in_seconds);
730 // Use the STW costs from the initial mark and remark plus
731 // the cost of the concurrent phase to calculate a
732 // collection cost.
733 double cost = 0.0;
734 if ((_latest_cms_ms_end_to_ms_start > 0.0) &&
735 (ms_time_in_seconds > 0.0)) {
736 double interval_in_seconds =
737 _latest_cms_ms_end_to_ms_start + ms_time_in_seconds;
739 if (PrintAdaptiveSizePolicy && Verbose) {
740 gclog_or_tty->print_cr("\n ms_time_in_seconds %f "
741 "latest_cms_sum_concurrent_phases_time_secs %f "
742 "interval_in_seconds %f",
743 ms_time_in_seconds,
744 latest_cms_sum_concurrent_phases_time_secs,
745 interval_in_seconds);
746 }
748 cost = collection_cost(ms_time_in_seconds, interval_in_seconds);
750 _avg_ms_gc_cost->sample(cost);
751 // Average this ms cost into all the other types gc costs
752 avg_major_gc_cost()->sample(cost);
754 // Sample for performance counter
755 _avg_ms_interval->sample(interval_in_seconds);
756 }
757 if (PrintAdaptiveSizePolicy && Verbose) {
758 gclog_or_tty->print("cmsAdaptiveSizePolicy::ms_collection_end: "
759 "MS gc cost: %f average: %f", cost, _avg_ms_gc_cost->average());
761 double ms_time_in_ms = ms_time_in_seconds * MILLIUNITS;
762 gclog_or_tty->print_cr(" MS pause: %f (ms) MS period %f (ms)",
763 ms_time_in_ms,
764 _latest_cms_ms_end_to_ms_start * MILLIUNITS);
765 }
766 }
768 // Consider putting this code (here to end) into a
769 // method for convenience.
770 clear_internal_time_intervals();
772 set_first_after_collection();
774 // The concurrent phases keeps track of it's own mutator interval
775 // with this timer. This allows the stop-the-world phase to
776 // be included in the mutator time so that the stop-the-world time
777 // is not double counted. Reset and start it.
778 _concurrent_timer.stop();
779 _concurrent_timer.reset();
780 _concurrent_timer.start();
782 _STW_timer.reset();
783 _STW_timer.start();
784 }
786 void CMSAdaptiveSizePolicy::clear_internal_time_intervals() {
787 _latest_cms_reset_end_to_initial_mark_start_secs = 0.0;
788 _latest_cms_initial_mark_end_to_remark_start_secs = 0.0;
789 _latest_cms_collection_end_to_collection_start_secs = 0.0;
790 _latest_cms_concurrent_marking_time_secs = 0.0;
791 _latest_cms_concurrent_precleaning_time_secs = 0.0;
792 _latest_cms_concurrent_sweeping_time_secs = 0.0;
793 _latest_cms_msc_end_to_msc_start_time_secs = 0.0;
794 _latest_cms_ms_end_to_ms_start = 0.0;
795 _latest_cms_remark_start_to_end_time_secs = 0.0;
796 _latest_cms_initial_mark_start_to_end_time_secs = 0.0;
797 _latest_cms_ms_marking_start_to_end_time_secs = 0.0;
798 }
800 void CMSAdaptiveSizePolicy::clear_generation_free_space_flags() {
801 AdaptiveSizePolicy::clear_generation_free_space_flags();
803 set_change_young_gen_for_maj_pauses(0);
804 }
806 void CMSAdaptiveSizePolicy::concurrent_phases_resume() {
807 if (PrintAdaptiveSizePolicy && Verbose) {
808 gclog_or_tty->stamp();
809 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::concurrent_phases_resume()");
810 }
811 _concurrent_timer.start();
812 }
814 double CMSAdaptiveSizePolicy::time_since_major_gc() const {
815 _concurrent_timer.stop();
816 double time_since_cms_gc = _concurrent_timer.seconds();
817 _concurrent_timer.start();
818 _STW_timer.stop();
819 double time_since_STW_gc = _STW_timer.seconds();
820 _STW_timer.start();
822 return MIN2(time_since_cms_gc, time_since_STW_gc);
823 }
825 double CMSAdaptiveSizePolicy::major_gc_interval_average_for_decay() const {
826 double cms_interval = _avg_concurrent_interval->average();
827 double msc_interval = _avg_msc_interval->average();
828 double ms_interval = _avg_ms_interval->average();
830 return MAX3(cms_interval, msc_interval, ms_interval);
831 }
833 double CMSAdaptiveSizePolicy::cms_gc_cost() const {
834 return avg_major_gc_cost()->average();
835 }
837 void CMSAdaptiveSizePolicy::ms_collection_marking_begin() {
838 _STW_timer.stop();
839 // Start accumumlating time for the marking in the STW timer.
840 _STW_timer.reset();
841 _STW_timer.start();
842 }
844 void CMSAdaptiveSizePolicy::ms_collection_marking_end(
845 GCCause::Cause gc_cause) {
846 _STW_timer.stop();
847 if (gc_cause != GCCause::_java_lang_system_gc ||
848 UseAdaptiveSizePolicyWithSystemGC) {
849 _latest_cms_ms_marking_start_to_end_time_secs = _STW_timer.seconds();
850 if (PrintAdaptiveSizePolicy && Verbose) {
851 gclog_or_tty->print_cr("CMSAdaptiveSizePolicy::"
852 "msc_collection_marking_end: mutator time %f",
853 _latest_cms_ms_marking_start_to_end_time_secs);
854 }
855 }
856 _STW_timer.reset();
857 _STW_timer.start();
858 }
860 double CMSAdaptiveSizePolicy::gc_cost() const {
861 double cms_gen_cost = cms_gc_cost();
862 double result = MIN2(1.0, minor_gc_cost() + cms_gen_cost);
863 assert(result >= 0.0, "Both minor and major costs are non-negative");
864 return result;
865 }
867 // Cost of collection (unit-less)
868 double CMSAdaptiveSizePolicy::collection_cost(double pause_in_seconds,
869 double interval_in_seconds) {
870 // Cost of collection (unit-less)
871 double cost = 0.0;
872 if ((interval_in_seconds > 0.0) &&
873 (pause_in_seconds > 0.0)) {
874 cost =
875 pause_in_seconds / interval_in_seconds;
876 }
877 return cost;
878 }
880 size_t CMSAdaptiveSizePolicy::adjust_eden_for_pause_time(size_t cur_eden) {
881 size_t change = 0;
882 size_t desired_eden = cur_eden;
884 // reduce eden size
885 change = eden_decrement_aligned_down(cur_eden);
886 desired_eden = cur_eden - change;
888 if (PrintAdaptiveSizePolicy && Verbose) {
889 gclog_or_tty->print_cr(
890 "CMSAdaptiveSizePolicy::adjust_eden_for_pause_time "
891 "adjusting eden for pause time. "
892 " starting eden size " SIZE_FORMAT
893 " reduced eden size " SIZE_FORMAT
894 " eden delta " SIZE_FORMAT,
895 cur_eden, desired_eden, change);
896 }
898 return desired_eden;
899 }
901 size_t CMSAdaptiveSizePolicy::adjust_eden_for_throughput(size_t cur_eden) {
903 size_t desired_eden = cur_eden;
905 set_change_young_gen_for_throughput(increase_young_gen_for_througput_true);
907 size_t change = eden_increment_aligned_up(cur_eden);
908 size_t scaled_change = scale_by_gen_gc_cost(change, minor_gc_cost());
910 if (cur_eden + scaled_change > cur_eden) {
911 desired_eden = cur_eden + scaled_change;
912 }
914 _young_gen_change_for_minor_throughput++;
916 if (PrintAdaptiveSizePolicy && Verbose) {
917 gclog_or_tty->print_cr(
918 "CMSAdaptiveSizePolicy::adjust_eden_for_throughput "
919 "adjusting eden for throughput. "
920 " starting eden size " SIZE_FORMAT
921 " increased eden size " SIZE_FORMAT
922 " eden delta " SIZE_FORMAT,
923 cur_eden, desired_eden, scaled_change);
924 }
926 return desired_eden;
927 }
929 size_t CMSAdaptiveSizePolicy::adjust_eden_for_footprint(size_t cur_eden) {
931 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
933 size_t change = eden_decrement(cur_eden);
934 size_t desired_eden_size = cur_eden - change;
936 if (PrintAdaptiveSizePolicy && Verbose) {
937 gclog_or_tty->print_cr(
938 "CMSAdaptiveSizePolicy::adjust_eden_for_footprint "
939 "adjusting eden for footprint. "
940 " starting eden size " SIZE_FORMAT
941 " reduced eden size " SIZE_FORMAT
942 " eden delta " SIZE_FORMAT,
943 cur_eden, desired_eden_size, change);
944 }
945 return desired_eden_size;
946 }
948 // The eden and promo versions should be combined if possible.
949 // They are the same except that the sizes of the decrement
950 // and increment are different for eden and promo.
951 size_t CMSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
952 size_t delta = eden_decrement(cur_eden);
953 return align_size_down(delta, generation_alignment());
954 }
956 size_t CMSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
957 size_t delta = eden_increment(cur_eden);
958 return align_size_up(delta, generation_alignment());
959 }
961 size_t CMSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
962 size_t delta = promo_decrement(cur_promo);
963 return align_size_down(delta, generation_alignment());
964 }
966 size_t CMSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
967 size_t delta = promo_increment(cur_promo);
968 return align_size_up(delta, generation_alignment());
969 }
972 void CMSAdaptiveSizePolicy::compute_young_generation_free_space(size_t cur_eden,
973 size_t max_eden_size)
974 {
975 size_t desired_eden_size = cur_eden;
976 size_t eden_limit = max_eden_size;
978 // Printout input
979 if (PrintGC && PrintAdaptiveSizePolicy) {
980 gclog_or_tty->print_cr(
981 "CMSAdaptiveSizePolicy::compute_young_generation_free_space: "
982 "cur_eden " SIZE_FORMAT,
983 cur_eden);
984 }
986 // Used for diagnostics
987 clear_generation_free_space_flags();
989 if (_avg_minor_pause->padded_average() > gc_pause_goal_sec()) {
990 if (minor_pause_young_estimator()->decrement_will_decrease()) {
991 // If the minor pause is too long, shrink the young gen.
992 set_change_young_gen_for_min_pauses(
993 decrease_young_gen_for_min_pauses_true);
994 desired_eden_size = adjust_eden_for_pause_time(desired_eden_size);
995 }
996 } else if ((avg_remark_pause()->padded_average() > gc_pause_goal_sec()) ||
997 (avg_initial_pause()->padded_average() > gc_pause_goal_sec())) {
998 // The remark or initial pauses are not meeting the goal. Should
999 // the generation be shrunk?
1000 if (get_and_clear_first_after_collection() &&
1001 ((avg_remark_pause()->padded_average() > gc_pause_goal_sec() &&
1002 remark_pause_young_estimator()->decrement_will_decrease()) ||
1003 (avg_initial_pause()->padded_average() > gc_pause_goal_sec() &&
1004 initial_pause_young_estimator()->decrement_will_decrease()))) {
1006 set_change_young_gen_for_maj_pauses(
1007 decrease_young_gen_for_maj_pauses_true);
1009 // If the remark or initial pause is too long and this is the
1010 // first young gen collection after a cms collection, shrink
1011 // the young gen.
1012 desired_eden_size = adjust_eden_for_pause_time(desired_eden_size);
1013 }
1014 // If not the first young gen collection after a cms collection,
1015 // don't do anything. In this case an adjustment has already
1016 // been made and the results of the adjustment has not yet been
1017 // measured.
1018 } else if ((minor_gc_cost() >= 0.0) &&
1019 (adjusted_mutator_cost() < _throughput_goal)) {
1020 desired_eden_size = adjust_eden_for_throughput(desired_eden_size);
1021 } else {
1022 desired_eden_size = adjust_eden_for_footprint(desired_eden_size);
1023 }
1025 if (PrintGC && PrintAdaptiveSizePolicy) {
1026 gclog_or_tty->print_cr(
1027 "CMSAdaptiveSizePolicy::compute_young_generation_free_space limits:"
1028 " desired_eden_size: " SIZE_FORMAT
1029 " old_eden_size: " SIZE_FORMAT,
1030 desired_eden_size, cur_eden);
1031 }
1033 set_eden_size(desired_eden_size);
1034 }
1036 size_t CMSAdaptiveSizePolicy::adjust_promo_for_pause_time(size_t cur_promo) {
1037 size_t change = 0;
1038 size_t desired_promo = cur_promo;
1039 // Move this test up to caller like the adjust_eden_for_pause_time()
1040 // call.
1041 if ((AdaptiveSizePausePolicy == 0) &&
1042 ((avg_remark_pause()->padded_average() > gc_pause_goal_sec()) ||
1043 (avg_initial_pause()->padded_average() > gc_pause_goal_sec()))) {
1044 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
1045 change = promo_decrement_aligned_down(cur_promo);
1046 desired_promo = cur_promo - change;
1047 } else if ((AdaptiveSizePausePolicy > 0) &&
1048 (((avg_remark_pause()->padded_average() > gc_pause_goal_sec()) &&
1049 remark_pause_old_estimator()->decrement_will_decrease()) ||
1050 ((avg_initial_pause()->padded_average() > gc_pause_goal_sec()) &&
1051 initial_pause_old_estimator()->decrement_will_decrease()))) {
1052 set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
1053 change = promo_decrement_aligned_down(cur_promo);
1054 desired_promo = cur_promo - change;
1055 }
1057 if ((change != 0) &&PrintAdaptiveSizePolicy && Verbose) {
1058 gclog_or_tty->print_cr(
1059 "CMSAdaptiveSizePolicy::adjust_promo_for_pause_time "
1060 "adjusting promo for pause time. "
1061 " starting promo size " SIZE_FORMAT
1062 " reduced promo size " SIZE_FORMAT
1063 " promo delta " SIZE_FORMAT,
1064 cur_promo, desired_promo, change);
1065 }
1067 return desired_promo;
1068 }
1070 // Try to share this with PS.
1071 size_t CMSAdaptiveSizePolicy::scale_by_gen_gc_cost(size_t base_change,
1072 double gen_gc_cost) {
1074 // Calculate the change to use for the tenured gen.
1075 size_t scaled_change = 0;
1076 // Can the increment to the generation be scaled?
1077 if (gc_cost() >= 0.0 && gen_gc_cost >= 0.0) {
1078 double scale_by_ratio = gen_gc_cost / gc_cost();
1079 scaled_change =
1080 (size_t) (scale_by_ratio * (double) base_change);
1081 if (PrintAdaptiveSizePolicy && Verbose) {
1082 gclog_or_tty->print_cr(
1083 "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
1084 SIZE_FORMAT,
1085 base_change, scale_by_ratio, scaled_change);
1086 }
1087 } else if (gen_gc_cost >= 0.0) {
1088 // Scaling is not going to work. If the major gc time is the
1089 // larger than the other GC costs, give it a full increment.
1090 if (gen_gc_cost >= (gc_cost() - gen_gc_cost)) {
1091 scaled_change = base_change;
1092 }
1093 } else {
1094 // Don't expect to get here but it's ok if it does
1095 // in the product build since the delta will be 0
1096 // and nothing will change.
1097 assert(false, "Unexpected value for gc costs");
1098 }
1100 return scaled_change;
1101 }
1103 size_t CMSAdaptiveSizePolicy::adjust_promo_for_throughput(size_t cur_promo) {
1105 size_t desired_promo = cur_promo;
1107 set_change_old_gen_for_throughput(increase_old_gen_for_throughput_true);
1109 size_t change = promo_increment_aligned_up(cur_promo);
1110 size_t scaled_change = scale_by_gen_gc_cost(change, major_gc_cost());
1112 if (cur_promo + scaled_change > cur_promo) {
1113 desired_promo = cur_promo + scaled_change;
1114 }
1116 _old_gen_change_for_major_throughput++;
1118 if (PrintAdaptiveSizePolicy && Verbose) {
1119 gclog_or_tty->print_cr(
1120 "CMSAdaptiveSizePolicy::adjust_promo_for_throughput "
1121 "adjusting promo for throughput. "
1122 " starting promo size " SIZE_FORMAT
1123 " increased promo size " SIZE_FORMAT
1124 " promo delta " SIZE_FORMAT,
1125 cur_promo, desired_promo, scaled_change);
1126 }
1128 return desired_promo;
1129 }
1131 size_t CMSAdaptiveSizePolicy::adjust_promo_for_footprint(size_t cur_promo,
1132 size_t cur_eden) {
1134 set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
1136 size_t change = promo_decrement(cur_promo);
1137 size_t desired_promo_size = cur_promo - change;
1139 if (PrintAdaptiveSizePolicy && Verbose) {
1140 gclog_or_tty->print_cr(
1141 "CMSAdaptiveSizePolicy::adjust_promo_for_footprint "
1142 "adjusting promo for footprint. "
1143 " starting promo size " SIZE_FORMAT
1144 " reduced promo size " SIZE_FORMAT
1145 " promo delta " SIZE_FORMAT,
1146 cur_promo, desired_promo_size, change);
1147 }
1148 return desired_promo_size;
1149 }
1151 void CMSAdaptiveSizePolicy::compute_tenured_generation_free_space(
1152 size_t cur_tenured_free,
1153 size_t max_tenured_available,
1154 size_t cur_eden) {
1155 // This can be bad if the desired value grows/shrinks without
1156 // any connection to the read free space
1157 size_t desired_promo_size = promo_size();
1158 size_t tenured_limit = max_tenured_available;
1160 // Printout input
1161 if (PrintGC && PrintAdaptiveSizePolicy) {
1162 gclog_or_tty->print_cr(
1163 "CMSAdaptiveSizePolicy::compute_tenured_generation_free_space: "
1164 "cur_tenured_free " SIZE_FORMAT
1165 " max_tenured_available " SIZE_FORMAT,
1166 cur_tenured_free, max_tenured_available);
1167 }
1169 // Used for diagnostics
1170 clear_generation_free_space_flags();
1172 set_decide_at_full_gc(decide_at_full_gc_true);
1173 if (avg_remark_pause()->padded_average() > gc_pause_goal_sec() ||
1174 avg_initial_pause()->padded_average() > gc_pause_goal_sec()) {
1175 desired_promo_size = adjust_promo_for_pause_time(cur_tenured_free);
1176 } else if (avg_minor_pause()->padded_average() > gc_pause_goal_sec()) {
1177 // Nothing to do since the minor collections are too large and
1178 // this method only deals with the cms generation.
1179 } else if ((cms_gc_cost() >= 0.0) &&
1180 (adjusted_mutator_cost() < _throughput_goal)) {
1181 desired_promo_size = adjust_promo_for_throughput(cur_tenured_free);
1182 } else {
1183 desired_promo_size = adjust_promo_for_footprint(cur_tenured_free,
1184 cur_eden);
1185 }
1187 if (PrintGC && PrintAdaptiveSizePolicy) {
1188 gclog_or_tty->print_cr(
1189 "CMSAdaptiveSizePolicy::compute_tenured_generation_free_space limits:"
1190 " desired_promo_size: " SIZE_FORMAT
1191 " old_promo_size: " SIZE_FORMAT,
1192 desired_promo_size, cur_tenured_free);
1193 }
1195 set_promo_size(desired_promo_size);
1196 }
1198 uint CMSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
1199 bool is_survivor_overflow,
1200 uint tenuring_threshold,
1201 size_t survivor_limit) {
1202 assert(survivor_limit >= generation_alignment(),
1203 "survivor_limit too small");
1204 assert((size_t)align_size_down(survivor_limit, generation_alignment())
1205 == survivor_limit, "survivor_limit not aligned");
1207 // Change UsePSAdaptiveSurvivorSizePolicy -> UseAdaptiveSurvivorSizePolicy?
1208 if (!UsePSAdaptiveSurvivorSizePolicy ||
1209 !young_gen_policy_is_ready()) {
1210 return tenuring_threshold;
1211 }
1213 // We'll decide whether to increase or decrease the tenuring
1214 // threshold based partly on the newly computed survivor size
1215 // (if we hit the maximum limit allowed, we'll always choose to
1216 // decrement the threshold).
1217 bool incr_tenuring_threshold = false;
1218 bool decr_tenuring_threshold = false;
1220 set_decrement_tenuring_threshold_for_gc_cost(false);
1221 set_increment_tenuring_threshold_for_gc_cost(false);
1222 set_decrement_tenuring_threshold_for_survivor_limit(false);
1224 if (!is_survivor_overflow) {
1225 // Keep running averages on how much survived
1227 // We use the tenuring threshold to equalize the cost of major
1228 // and minor collections.
1229 // ThresholdTolerance is used to indicate how sensitive the
1230 // tenuring threshold is to differences in cost betweent the
1231 // collection types.
1233 // Get the times of interest. This involves a little work, so
1234 // we cache the values here.
1235 const double major_cost = major_gc_cost();
1236 const double minor_cost = minor_gc_cost();
1238 if (minor_cost > major_cost * _threshold_tolerance_percent) {
1239 // Minor times are getting too long; lower the threshold so
1240 // less survives and more is promoted.
1241 decr_tenuring_threshold = true;
1242 set_decrement_tenuring_threshold_for_gc_cost(true);
1243 } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
1244 // Major times are too long, so we want less promotion.
1245 incr_tenuring_threshold = true;
1246 set_increment_tenuring_threshold_for_gc_cost(true);
1247 }
1249 } else {
1250 // Survivor space overflow occurred, so promoted and survived are
1251 // not accurate. We'll make our best guess by combining survived
1252 // and promoted and count them as survivors.
1253 //
1254 // We'll lower the tenuring threshold to see if we can correct
1255 // things. Also, set the survivor size conservatively. We're
1256 // trying to avoid many overflows from occurring if defnew size
1257 // is just too small.
1259 decr_tenuring_threshold = true;
1260 }
1262 // The padded average also maintains a deviation from the average;
1263 // we use this to see how good of an estimate we have of what survived.
1264 // We're trying to pad the survivor size as little as possible without
1265 // overflowing the survivor spaces.
1266 size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
1267 generation_alignment());
1268 target_size = MAX2(target_size, generation_alignment());
1270 if (target_size > survivor_limit) {
1271 // Target size is bigger than we can handle. Let's also reduce
1272 // the tenuring threshold.
1273 target_size = survivor_limit;
1274 decr_tenuring_threshold = true;
1275 set_decrement_tenuring_threshold_for_survivor_limit(true);
1276 }
1278 // Finally, increment or decrement the tenuring threshold, as decided above.
1279 // We test for decrementing first, as we might have hit the target size
1280 // limit.
1281 if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1282 if (tenuring_threshold > 1) {
1283 tenuring_threshold--;
1284 }
1285 } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
1286 if (tenuring_threshold < MaxTenuringThreshold) {
1287 tenuring_threshold++;
1288 }
1289 }
1291 // We keep a running average of the amount promoted which is used
1292 // to decide when we should collect the old generation (when
1293 // the amount of old gen free space is less than what we expect to
1294 // promote).
1296 if (PrintAdaptiveSizePolicy) {
1297 // A little more detail if Verbose is on
1298 GenCollectedHeap* gch = GenCollectedHeap::heap();
1299 if (Verbose) {
1300 gclog_or_tty->print( " avg_survived: %f"
1301 " avg_deviation: %f",
1302 _avg_survived->average(),
1303 _avg_survived->deviation());
1304 }
1306 gclog_or_tty->print( " avg_survived_padded_avg: %f",
1307 _avg_survived->padded_average());
1309 if (Verbose) {
1310 gclog_or_tty->print( " avg_promoted_avg: %f"
1311 " avg_promoted_dev: %f",
1312 gch->gc_stats(1)->avg_promoted()->average(),
1313 gch->gc_stats(1)->avg_promoted()->deviation());
1314 }
1316 gclog_or_tty->print( " avg_promoted_padded_avg: %f"
1317 " avg_pretenured_padded_avg: %f"
1318 " tenuring_thresh: %u"
1319 " target_size: " SIZE_FORMAT
1320 " survivor_limit: " SIZE_FORMAT,
1321 gch->gc_stats(1)->avg_promoted()->padded_average(),
1322 _avg_pretenured->padded_average(),
1323 tenuring_threshold, target_size, survivor_limit);
1324 gclog_or_tty->cr();
1325 }
1327 set_survivor_size(target_size);
1329 return tenuring_threshold;
1330 }
1332 bool CMSAdaptiveSizePolicy::get_and_clear_first_after_collection() {
1333 bool result = _first_after_collection;
1334 _first_after_collection = false;
1335 return result;
1336 }
1338 bool CMSAdaptiveSizePolicy::print_adaptive_size_policy_on(
1339 outputStream* st) const {
1341 if (!UseAdaptiveSizePolicy) return false;
1343 GenCollectedHeap* gch = GenCollectedHeap::heap();
1344 Generation* gen0 = gch->get_gen(0);
1345 DefNewGeneration* def_new = gen0->as_DefNewGeneration();
1346 return
1347 AdaptiveSizePolicy::print_adaptive_size_policy_on(
1348 st,
1349 def_new->tenuring_threshold());
1350 }
