Mercurial > hg > truffle
comparison src/share/vm/gc_implementation/shared/adaptiveSizePolicy.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 0bfd3fb24150 |
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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 } |