Mercurial > hg > graal-jvmci-8

comparison src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp @ 0:a61af66fc99e jdk7-b24

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Initial load
author duke
date Sat, 01 Dec 2007 00:00:00 +0000
parents
children 0bfd3fb24150
comparison
equal deleted inserted replaced
-1:000000000000 0:a61af66fc99e
1 /*
2 * Copyright 2004-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24 #include "incls/_precompiled.incl"
25 #include "incls/_adaptiveSizePolicy.cpp.incl"
26
27 elapsedTimer AdaptiveSizePolicy::_minor_timer;
28 elapsedTimer AdaptiveSizePolicy::_major_timer;
29
30 // The throughput goal is implemented as
31 // _throughput_goal = 1 - ( 1 / (1 + gc_cost_ratio))
32 // gc_cost_ratio is the ratio
33 // application cost / gc cost
34 // For example a gc_cost_ratio of 4 translates into a
35 // throughput goal of .80
36
37 AdaptiveSizePolicy::AdaptiveSizePolicy(size_t init_eden_size,
38 size_t init_promo_size,
39 size_t init_survivor_size,
40 double gc_pause_goal_sec,
41 uint gc_cost_ratio) :
42 _eden_size(init_eden_size),
43 _promo_size(init_promo_size),
44 _survivor_size(init_survivor_size),
45 _gc_pause_goal_sec(gc_pause_goal_sec),
46 _throughput_goal(1.0 - double(1.0 / (1.0 + (double) gc_cost_ratio))),
47 _gc_time_limit_exceeded(false),
48 _print_gc_time_limit_would_be_exceeded(false),
49 _gc_time_limit_count(0),
50 _latest_minor_mutator_interval_seconds(0),
51 _threshold_tolerance_percent(1.0 + ThresholdTolerance/100.0),
52 _young_gen_change_for_minor_throughput(0),
53 _old_gen_change_for_major_throughput(0) {
54 _avg_minor_pause =
55 new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
56 _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
57 _avg_minor_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
58 _avg_major_gc_cost = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
59
60 _avg_young_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
61 _avg_old_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
62 _avg_eden_live = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
63
64 _avg_survived = new AdaptivePaddedAverage(AdaptiveSizePolicyWeight,
65 SurvivorPadding);
66 _avg_pretenured = new AdaptivePaddedNoZeroDevAverage(
67 AdaptiveSizePolicyWeight,
68 SurvivorPadding);
69
70 _minor_pause_old_estimator =
71 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
72 _minor_pause_young_estimator =
73 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
74 _minor_collection_estimator =
75 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
76 _major_collection_estimator =
77 new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
78
79 // Start the timers
80 _minor_timer.start();
81
82 _young_gen_policy_is_ready = false;
83 }
84
85 bool AdaptiveSizePolicy::tenuring_threshold_change() const {
86 return decrement_tenuring_threshold_for_gc_cost() ||
87 increment_tenuring_threshold_for_gc_cost() ||
88 decrement_tenuring_threshold_for_survivor_limit();
89 }
90
91 void AdaptiveSizePolicy::minor_collection_begin() {
92 // Update the interval time
93 _minor_timer.stop();
94 // Save most recent collection time
95 _latest_minor_mutator_interval_seconds = _minor_timer.seconds();
96 _minor_timer.reset();
97 _minor_timer.start();
98 }
99
100 void AdaptiveSizePolicy::update_minor_pause_young_estimator(
101 double minor_pause_in_ms) {
102 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
103 _minor_pause_young_estimator->update(eden_size_in_mbytes,
104 minor_pause_in_ms);
105 }
106
107 void AdaptiveSizePolicy::minor_collection_end(GCCause::Cause gc_cause) {
108 // Update the pause time.
109 _minor_timer.stop();
110
111 if (gc_cause != GCCause::_java_lang_system_gc ||
112 UseAdaptiveSizePolicyWithSystemGC) {
113 double minor_pause_in_seconds = _minor_timer.seconds();
114 double minor_pause_in_ms = minor_pause_in_seconds * MILLIUNITS;
115
116 // Sample for performance counter
117 _avg_minor_pause->sample(minor_pause_in_seconds);
118
119 // Cost of collection (unit-less)
120 double collection_cost = 0.0;
121 if ((_latest_minor_mutator_interval_seconds > 0.0) &&
122 (minor_pause_in_seconds > 0.0)) {
123 double interval_in_seconds =
124 _latest_minor_mutator_interval_seconds + minor_pause_in_seconds;
125 collection_cost =
126 minor_pause_in_seconds / interval_in_seconds;
127 _avg_minor_gc_cost->sample(collection_cost);
128 // Sample for performance counter
129 _avg_minor_interval->sample(interval_in_seconds);
130 }
131
132 // The policy does not have enough data until at least some
133 // minor collections have been done.
134 _young_gen_policy_is_ready =
135 (_avg_minor_gc_cost->count() >= AdaptiveSizePolicyReadyThreshold);
136
137 // Calculate variables used to estimate pause time vs. gen sizes
138 double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
139 update_minor_pause_young_estimator(minor_pause_in_ms);
140 update_minor_pause_old_estimator(minor_pause_in_ms);
141
142 if (PrintAdaptiveSizePolicy && Verbose) {
143 gclog_or_tty->print("AdaptiveSizePolicy::minor_collection_end: "
144 "minor gc cost: %f average: %f", collection_cost,
145 _avg_minor_gc_cost->average());
146 gclog_or_tty->print_cr(" minor pause: %f minor period %f",
147 minor_pause_in_ms,
148 _latest_minor_mutator_interval_seconds * MILLIUNITS);
149 }
150
151 // Calculate variable used to estimate collection cost vs. gen sizes
152 assert(collection_cost >= 0.0, "Expected to be non-negative");
153 _minor_collection_estimator->update(eden_size_in_mbytes, collection_cost);
154 }
155
156 // Interval times use this timer to measure the mutator time.
157 // Reset the timer after the GC pause.
158 _minor_timer.reset();
159 _minor_timer.start();
160 }
161
162 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden,
163 uint percent_change) {
164 size_t eden_heap_delta;
165 eden_heap_delta = cur_eden / 100 * percent_change;
166 return eden_heap_delta;
167 }
168
169 size_t AdaptiveSizePolicy::eden_increment(size_t cur_eden) {
170 return eden_increment(cur_eden, YoungGenerationSizeIncrement);
171 }
172
173 size_t AdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
174 size_t eden_heap_delta = eden_increment(cur_eden) /
175 AdaptiveSizeDecrementScaleFactor;
176 return eden_heap_delta;
177 }
178
179 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo,
180 uint percent_change) {
181 size_t promo_heap_delta;
182 promo_heap_delta = cur_promo / 100 * percent_change;
183 return promo_heap_delta;
184 }
185
186 size_t AdaptiveSizePolicy::promo_increment(size_t cur_promo) {
187 return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
188 }
189
190 size_t AdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
191 size_t promo_heap_delta = promo_increment(cur_promo);
192 promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
193 return promo_heap_delta;
194 }
195
196 double AdaptiveSizePolicy::time_since_major_gc() const {
197 _major_timer.stop();
198 double result = _major_timer.seconds();
199 _major_timer.start();
200 return result;
201 }
202
203 // Linear decay of major gc cost
204 double AdaptiveSizePolicy::decaying_major_gc_cost() const {
205 double major_interval = major_gc_interval_average_for_decay();
206 double major_gc_cost_average = major_gc_cost();
207 double decayed_major_gc_cost = major_gc_cost_average;
208 if(time_since_major_gc() > 0.0) {
209 decayed_major_gc_cost = major_gc_cost() *
210 (((double) AdaptiveSizeMajorGCDecayTimeScale) * major_interval)
211 / time_since_major_gc();
212 }
213
214 // The decayed cost should always be smaller than the
215 // average cost but the vagaries of finite arithmetic could
216 // produce a larger value in decayed_major_gc_cost so protect
217 // against that.
218 return MIN2(major_gc_cost_average, decayed_major_gc_cost);
219 }
220
221 // Use a value of the major gc cost that has been decayed
222 // by the factor
223 //
224 // average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale /
225 // time-since-last-major-gc
226 //
227 // if the average-interval-between-major-gc * AdaptiveSizeMajorGCDecayTimeScale
228 // is less than time-since-last-major-gc.
229 //
230 // In cases where there are initial major gc's that
231 // are of a relatively high cost but no later major
232 // gc's, the total gc cost can remain high because
233 // the major gc cost remains unchanged (since there are no major
234 // gc's). In such a situation the value of the unchanging
235 // major gc cost can keep the mutator throughput below
236 // the goal when in fact the major gc cost is becoming diminishingly
237 // small. Use the decaying gc cost only to decide whether to
238 // adjust for throughput. Using it also to determine the adjustment
239 // to be made for throughput also seems reasonable but there is
240 // no test case to use to decide if it is the right thing to do
241 // don't do it yet.
242
243 double AdaptiveSizePolicy::decaying_gc_cost() const {
244 double decayed_major_gc_cost = major_gc_cost();
245 double avg_major_interval = major_gc_interval_average_for_decay();
246 if (UseAdaptiveSizeDecayMajorGCCost &&
247 (AdaptiveSizeMajorGCDecayTimeScale > 0) &&
248 (avg_major_interval > 0.00)) {
249 double time_since_last_major_gc = time_since_major_gc();
250
251 // Decay the major gc cost?
252 if (time_since_last_major_gc >
253 ((double) AdaptiveSizeMajorGCDecayTimeScale) * avg_major_interval) {
254
255 // Decay using the time-since-last-major-gc
256 decayed_major_gc_cost = decaying_major_gc_cost();
257 if (PrintGCDetails && Verbose) {
258 gclog_or_tty->print_cr("\ndecaying_gc_cost: major interval average:"
259 " %f time since last major gc: %f",
260 avg_major_interval, time_since_last_major_gc);
261 gclog_or_tty->print_cr(" major gc cost: %f decayed major gc cost: %f",
262 major_gc_cost(), decayed_major_gc_cost);
263 }
264 }
265 }
266 double result = MIN2(1.0, decayed_major_gc_cost + minor_gc_cost());
267 return result;
268 }
269
270
271 void AdaptiveSizePolicy::clear_generation_free_space_flags() {
272 set_change_young_gen_for_min_pauses(0);
273 set_change_old_gen_for_maj_pauses(0);
274
275 set_change_old_gen_for_throughput(0);
276 set_change_young_gen_for_throughput(0);
277 set_decrease_for_footprint(0);
278 set_decide_at_full_gc(0);
279 }
280
281 // Printing
282
283 bool AdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st) const {
284
285 // Should only be used with adaptive size policy turned on.
286 // Otherwise, there may be variables that are undefined.
287 if (!UseAdaptiveSizePolicy) return false;
288
289 // Print goal for which action is needed.
290 char* action = NULL;
291 bool change_for_pause = false;
292 if ((change_old_gen_for_maj_pauses() ==
293 decrease_old_gen_for_maj_pauses_true) ||
294 (change_young_gen_for_min_pauses() ==
295 decrease_young_gen_for_min_pauses_true)) {
296 action = (char*) " *** pause time goal ***";
297 change_for_pause = true;
298 } else if ((change_old_gen_for_throughput() ==
299 increase_old_gen_for_throughput_true) ||
300 (change_young_gen_for_throughput() ==
301 increase_young_gen_for_througput_true)) {
302 action = (char*) " *** throughput goal ***";
303 } else if (decrease_for_footprint()) {
304 action = (char*) " *** reduced footprint ***";
305 } else {
306 // No actions were taken. This can legitimately be the
307 // situation if not enough data has been gathered to make
308 // decisions.
309 return false;
310 }
311
312 // Pauses
313 // Currently the size of the old gen is only adjusted to
314 // change the major pause times.
315 char* young_gen_action = NULL;
316 char* tenured_gen_action = NULL;
317
318 char* shrink_msg = (char*) "(attempted to shrink)";
319 char* grow_msg = (char*) "(attempted to grow)";
320 char* no_change_msg = (char*) "(no change)";
321 if (change_young_gen_for_min_pauses() ==
322 decrease_young_gen_for_min_pauses_true) {
323 young_gen_action = shrink_msg;
324 } else if (change_for_pause) {
325 young_gen_action = no_change_msg;
326 }
327
328 if (change_old_gen_for_maj_pauses() == decrease_old_gen_for_maj_pauses_true) {
329 tenured_gen_action = shrink_msg;
330 } else if (change_for_pause) {
331 tenured_gen_action = no_change_msg;
332 }
333
334 // Throughput
335 if (change_old_gen_for_throughput() == increase_old_gen_for_throughput_true) {
336 assert(change_young_gen_for_throughput() ==
337 increase_young_gen_for_througput_true,
338 "Both generations should be growing");
339 young_gen_action = grow_msg;
340 tenured_gen_action = grow_msg;
341 } else if (change_young_gen_for_throughput() ==
342 increase_young_gen_for_througput_true) {
343 // Only the young generation may grow at start up (before
344 // enough full collections have been done to grow the old generation).
345 young_gen_action = grow_msg;
346 tenured_gen_action = no_change_msg;
347 }
348
349 // Minimum footprint
350 if (decrease_for_footprint() != 0) {
351 young_gen_action = shrink_msg;
352 tenured_gen_action = shrink_msg;
353 }
354
355 st->print_cr(" UseAdaptiveSizePolicy actions to meet %s", action);
356 st->print_cr(" GC overhead (%%)");
357 st->print_cr(" Young generation: %7.2f\t %s",
358 100.0 * avg_minor_gc_cost()->average(),
359 young_gen_action);
360 st->print_cr(" Tenured generation: %7.2f\t %s",
361 100.0 * avg_major_gc_cost()->average(),
362 tenured_gen_action);
363 return true;
364 }
365
366 bool AdaptiveSizePolicy::print_adaptive_size_policy_on(
367 outputStream* st,
368 int tenuring_threshold_arg) const {
369 if (!AdaptiveSizePolicy::print_adaptive_size_policy_on(st)) {
370 return false;
371 }
372
373 // Tenuring threshold
374 bool tenuring_threshold_changed = true;
375 if (decrement_tenuring_threshold_for_survivor_limit()) {
376 st->print(" Tenuring threshold: (attempted to decrease to avoid"
377 " survivor space overflow) = ");
378 } else if (decrement_tenuring_threshold_for_gc_cost()) {
379 st->print(" Tenuring threshold: (attempted to decrease to balance"
380 " GC costs) = ");
381 } else if (increment_tenuring_threshold_for_gc_cost()) {
382 st->print(" Tenuring threshold: (attempted to increase to balance"
383 " GC costs) = ");
384 } else {
385 tenuring_threshold_changed = false;
386 assert(!tenuring_threshold_change(), "(no change was attempted)");
387 }
388 if (tenuring_threshold_changed) {
389 st->print_cr("%d", tenuring_threshold_arg);
390 }
391 return true;
392 }