Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp @ 883:27f6a9b9c311
6864886: G1: rename -XX parameters related to update buffers
Summary: renaming a couple of update buffer-related parameters to make them more understandable and consistent.
Reviewed-by: iveresov, ysr
author | tonyp |
---|---|
date | Wed, 29 Jul 2009 11:01:26 -0400 |
parents | 0316eac49d5a |
children | 6cb8e9df7174 |
rev | line source |
---|---|
342 | 1 /* |
579 | 2 * Copyright 2001-2009 Sun Microsystems, Inc. All Rights Reserved. |
342 | 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 | |
25 // A G1CollectorPolicy makes policy decisions that determine the | |
26 // characteristics of the collector. Examples include: | |
27 // * choice of collection set. | |
28 // * when to collect. | |
29 | |
30 class HeapRegion; | |
31 class CollectionSetChooser; | |
32 | |
33 // Yes, this is a bit unpleasant... but it saves replicating the same thing | |
34 // over and over again and introducing subtle problems through small typos and | |
35 // cutting and pasting mistakes. The macros below introduces a number | |
36 // sequnce into the following two classes and the methods that access it. | |
37 | |
38 #define define_num_seq(name) \ | |
39 private: \ | |
40 NumberSeq _all_##name##_times_ms; \ | |
41 public: \ | |
42 void record_##name##_time_ms(double ms) { \ | |
43 _all_##name##_times_ms.add(ms); \ | |
44 } \ | |
45 NumberSeq* get_##name##_seq() { \ | |
46 return &_all_##name##_times_ms; \ | |
47 } | |
48 | |
49 class MainBodySummary; | |
50 | |
549
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6700941: G1: allocation spec missing for some G1 classes
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51 class PauseSummary: public CHeapObj { |
342 | 52 define_num_seq(total) |
53 define_num_seq(other) | |
54 | |
55 public: | |
56 virtual MainBodySummary* main_body_summary() { return NULL; } | |
57 }; | |
58 | |
549
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59 class MainBodySummary: public CHeapObj { |
342 | 60 define_num_seq(satb_drain) // optional |
61 define_num_seq(parallel) // parallel only | |
62 define_num_seq(ext_root_scan) | |
63 define_num_seq(mark_stack_scan) | |
64 define_num_seq(scan_only) | |
65 define_num_seq(update_rs) | |
66 define_num_seq(scan_rs) | |
67 define_num_seq(scan_new_refs) // Only for temp use; added to | |
68 // in parallel case. | |
69 define_num_seq(obj_copy) | |
70 define_num_seq(termination) // parallel only | |
71 define_num_seq(parallel_other) // parallel only | |
72 define_num_seq(mark_closure) | |
73 define_num_seq(clear_ct) // parallel only | |
74 }; | |
75 | |
677 | 76 class Summary: public PauseSummary, |
77 public MainBodySummary { | |
342 | 78 public: |
79 virtual MainBodySummary* main_body_summary() { return this; } | |
80 }; | |
81 | |
677 | 82 class AbandonedSummary: public PauseSummary { |
342 | 83 }; |
84 | |
85 class G1CollectorPolicy: public CollectorPolicy { | |
86 protected: | |
87 // The number of pauses during the execution. | |
88 long _n_pauses; | |
89 | |
90 // either equal to the number of parallel threads, if ParallelGCThreads | |
91 // has been set, or 1 otherwise | |
92 int _parallel_gc_threads; | |
93 | |
94 enum SomePrivateConstants { | |
95 NumPrevPausesForHeuristics = 10, | |
96 NumPrevGCsForHeuristics = 10, | |
97 NumAPIs = HeapRegion::MaxAge | |
98 }; | |
99 | |
100 G1MMUTracker* _mmu_tracker; | |
101 | |
102 void initialize_flags(); | |
103 | |
104 void initialize_all() { | |
105 initialize_flags(); | |
106 initialize_size_info(); | |
107 initialize_perm_generation(PermGen::MarkSweepCompact); | |
108 } | |
109 | |
110 virtual size_t default_init_heap_size() { | |
111 // Pick some reasonable default. | |
112 return 8*M; | |
113 } | |
114 | |
115 | |
116 double _cur_collection_start_sec; | |
117 size_t _cur_collection_pause_used_at_start_bytes; | |
118 size_t _cur_collection_pause_used_regions_at_start; | |
119 size_t _prev_collection_pause_used_at_end_bytes; | |
120 double _cur_collection_par_time_ms; | |
121 double _cur_satb_drain_time_ms; | |
122 double _cur_clear_ct_time_ms; | |
123 bool _satb_drain_time_set; | |
124 | |
125 double _cur_CH_strong_roots_end_sec; | |
126 double _cur_CH_strong_roots_dur_ms; | |
127 double _cur_G1_strong_roots_end_sec; | |
128 double _cur_G1_strong_roots_dur_ms; | |
129 | |
130 // Statistics for recent GC pauses. See below for how indexed. | |
131 TruncatedSeq* _recent_CH_strong_roots_times_ms; | |
132 TruncatedSeq* _recent_G1_strong_roots_times_ms; | |
133 TruncatedSeq* _recent_evac_times_ms; | |
134 // These exclude marking times. | |
135 TruncatedSeq* _recent_pause_times_ms; | |
136 TruncatedSeq* _recent_gc_times_ms; | |
137 | |
138 TruncatedSeq* _recent_CS_bytes_used_before; | |
139 TruncatedSeq* _recent_CS_bytes_surviving; | |
140 | |
141 TruncatedSeq* _recent_rs_sizes; | |
142 | |
143 TruncatedSeq* _concurrent_mark_init_times_ms; | |
144 TruncatedSeq* _concurrent_mark_remark_times_ms; | |
145 TruncatedSeq* _concurrent_mark_cleanup_times_ms; | |
146 | |
677 | 147 Summary* _summary; |
148 AbandonedSummary* _abandoned_summary; | |
342 | 149 |
150 NumberSeq* _all_pause_times_ms; | |
151 NumberSeq* _all_full_gc_times_ms; | |
152 double _stop_world_start; | |
153 NumberSeq* _all_stop_world_times_ms; | |
154 NumberSeq* _all_yield_times_ms; | |
155 | |
156 size_t _region_num_young; | |
157 size_t _region_num_tenured; | |
158 size_t _prev_region_num_young; | |
159 size_t _prev_region_num_tenured; | |
160 | |
161 NumberSeq* _all_mod_union_times_ms; | |
162 | |
163 int _aux_num; | |
164 NumberSeq* _all_aux_times_ms; | |
165 double* _cur_aux_start_times_ms; | |
166 double* _cur_aux_times_ms; | |
167 bool* _cur_aux_times_set; | |
168 | |
169 double* _par_last_ext_root_scan_times_ms; | |
170 double* _par_last_mark_stack_scan_times_ms; | |
171 double* _par_last_scan_only_times_ms; | |
172 double* _par_last_scan_only_regions_scanned; | |
173 double* _par_last_update_rs_start_times_ms; | |
174 double* _par_last_update_rs_times_ms; | |
175 double* _par_last_update_rs_processed_buffers; | |
176 double* _par_last_scan_rs_start_times_ms; | |
177 double* _par_last_scan_rs_times_ms; | |
178 double* _par_last_scan_new_refs_times_ms; | |
179 double* _par_last_obj_copy_times_ms; | |
180 double* _par_last_termination_times_ms; | |
181 | |
182 // indicates that we are in young GC mode | |
183 bool _in_young_gc_mode; | |
184 | |
185 // indicates whether we are in full young or partially young GC mode | |
186 bool _full_young_gcs; | |
187 | |
188 // if true, then it tries to dynamically adjust the length of the | |
189 // young list | |
190 bool _adaptive_young_list_length; | |
191 size_t _young_list_min_length; | |
192 size_t _young_list_target_length; | |
193 size_t _young_list_so_prefix_length; | |
194 size_t _young_list_fixed_length; | |
195 | |
196 size_t _young_cset_length; | |
197 bool _last_young_gc_full; | |
198 | |
199 double _target_pause_time_ms; | |
200 | |
201 unsigned _full_young_pause_num; | |
202 unsigned _partial_young_pause_num; | |
203 | |
204 bool _during_marking; | |
205 bool _in_marking_window; | |
206 bool _in_marking_window_im; | |
207 | |
208 SurvRateGroup* _short_lived_surv_rate_group; | |
209 SurvRateGroup* _survivor_surv_rate_group; | |
210 // add here any more surv rate groups | |
211 | |
212 bool during_marking() { | |
213 return _during_marking; | |
214 } | |
215 | |
216 // <NEW PREDICTION> | |
217 | |
218 private: | |
219 enum PredictionConstants { | |
220 TruncatedSeqLength = 10 | |
221 }; | |
222 | |
223 TruncatedSeq* _alloc_rate_ms_seq; | |
224 double _prev_collection_pause_end_ms; | |
225 | |
226 TruncatedSeq* _pending_card_diff_seq; | |
227 TruncatedSeq* _rs_length_diff_seq; | |
228 TruncatedSeq* _cost_per_card_ms_seq; | |
229 TruncatedSeq* _cost_per_scan_only_region_ms_seq; | |
230 TruncatedSeq* _fully_young_cards_per_entry_ratio_seq; | |
231 TruncatedSeq* _partially_young_cards_per_entry_ratio_seq; | |
232 TruncatedSeq* _cost_per_entry_ms_seq; | |
233 TruncatedSeq* _partially_young_cost_per_entry_ms_seq; | |
234 TruncatedSeq* _cost_per_byte_ms_seq; | |
235 TruncatedSeq* _constant_other_time_ms_seq; | |
236 TruncatedSeq* _young_other_cost_per_region_ms_seq; | |
237 TruncatedSeq* _non_young_other_cost_per_region_ms_seq; | |
238 | |
239 TruncatedSeq* _pending_cards_seq; | |
240 TruncatedSeq* _scanned_cards_seq; | |
241 TruncatedSeq* _rs_lengths_seq; | |
242 | |
243 TruncatedSeq* _cost_per_byte_ms_during_cm_seq; | |
244 TruncatedSeq* _cost_per_scan_only_region_ms_during_cm_seq; | |
245 | |
246 TruncatedSeq* _young_gc_eff_seq; | |
247 | |
248 TruncatedSeq* _max_conc_overhead_seq; | |
249 | |
250 size_t _recorded_young_regions; | |
251 size_t _recorded_scan_only_regions; | |
252 size_t _recorded_non_young_regions; | |
253 size_t _recorded_region_num; | |
254 | |
255 size_t _free_regions_at_end_of_collection; | |
256 size_t _scan_only_regions_at_end_of_collection; | |
257 | |
258 size_t _recorded_rs_lengths; | |
259 size_t _max_rs_lengths; | |
260 | |
261 size_t _recorded_marked_bytes; | |
262 size_t _recorded_young_bytes; | |
263 | |
264 size_t _predicted_pending_cards; | |
265 size_t _predicted_cards_scanned; | |
266 size_t _predicted_rs_lengths; | |
267 size_t _predicted_bytes_to_copy; | |
268 | |
269 double _predicted_survival_ratio; | |
270 double _predicted_rs_update_time_ms; | |
271 double _predicted_rs_scan_time_ms; | |
272 double _predicted_scan_only_scan_time_ms; | |
273 double _predicted_object_copy_time_ms; | |
274 double _predicted_constant_other_time_ms; | |
275 double _predicted_young_other_time_ms; | |
276 double _predicted_non_young_other_time_ms; | |
277 double _predicted_pause_time_ms; | |
278 | |
279 double _vtime_diff_ms; | |
280 | |
281 double _recorded_young_free_cset_time_ms; | |
282 double _recorded_non_young_free_cset_time_ms; | |
283 | |
284 double _sigma; | |
285 double _expensive_region_limit_ms; | |
286 | |
287 size_t _rs_lengths_prediction; | |
288 | |
289 size_t _known_garbage_bytes; | |
290 double _known_garbage_ratio; | |
291 | |
292 double sigma() { | |
293 return _sigma; | |
294 } | |
295 | |
296 // A function that prevents us putting too much stock in small sample | |
297 // sets. Returns a number between 2.0 and 1.0, depending on the number | |
298 // of samples. 5 or more samples yields one; fewer scales linearly from | |
299 // 2.0 at 1 sample to 1.0 at 5. | |
300 double confidence_factor(int samples) { | |
301 if (samples > 4) return 1.0; | |
302 else return 1.0 + sigma() * ((double)(5 - samples))/2.0; | |
303 } | |
304 | |
305 double get_new_neg_prediction(TruncatedSeq* seq) { | |
306 return seq->davg() - sigma() * seq->dsd(); | |
307 } | |
308 | |
309 #ifndef PRODUCT | |
310 bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group); | |
311 #endif // PRODUCT | |
312 | |
313 protected: | |
314 double _pause_time_target_ms; | |
315 double _recorded_young_cset_choice_time_ms; | |
316 double _recorded_non_young_cset_choice_time_ms; | |
317 bool _within_target; | |
318 size_t _pending_cards; | |
319 size_t _max_pending_cards; | |
320 | |
321 public: | |
322 | |
323 void set_region_short_lived(HeapRegion* hr) { | |
324 hr->install_surv_rate_group(_short_lived_surv_rate_group); | |
325 } | |
326 | |
327 void set_region_survivors(HeapRegion* hr) { | |
328 hr->install_surv_rate_group(_survivor_surv_rate_group); | |
329 } | |
330 | |
331 #ifndef PRODUCT | |
332 bool verify_young_ages(); | |
333 #endif // PRODUCT | |
334 | |
335 void tag_scan_only(size_t short_lived_scan_only_length); | |
336 | |
337 double get_new_prediction(TruncatedSeq* seq) { | |
338 return MAX2(seq->davg() + sigma() * seq->dsd(), | |
339 seq->davg() * confidence_factor(seq->num())); | |
340 } | |
341 | |
342 size_t young_cset_length() { | |
343 return _young_cset_length; | |
344 } | |
345 | |
346 void record_max_rs_lengths(size_t rs_lengths) { | |
347 _max_rs_lengths = rs_lengths; | |
348 } | |
349 | |
350 size_t predict_pending_card_diff() { | |
351 double prediction = get_new_neg_prediction(_pending_card_diff_seq); | |
352 if (prediction < 0.00001) | |
353 return 0; | |
354 else | |
355 return (size_t) prediction; | |
356 } | |
357 | |
358 size_t predict_pending_cards() { | |
359 size_t max_pending_card_num = _g1->max_pending_card_num(); | |
360 size_t diff = predict_pending_card_diff(); | |
361 size_t prediction; | |
362 if (diff > max_pending_card_num) | |
363 prediction = max_pending_card_num; | |
364 else | |
365 prediction = max_pending_card_num - diff; | |
366 | |
367 return prediction; | |
368 } | |
369 | |
370 size_t predict_rs_length_diff() { | |
371 return (size_t) get_new_prediction(_rs_length_diff_seq); | |
372 } | |
373 | |
374 double predict_alloc_rate_ms() { | |
375 return get_new_prediction(_alloc_rate_ms_seq); | |
376 } | |
377 | |
378 double predict_cost_per_card_ms() { | |
379 return get_new_prediction(_cost_per_card_ms_seq); | |
380 } | |
381 | |
382 double predict_rs_update_time_ms(size_t pending_cards) { | |
383 return (double) pending_cards * predict_cost_per_card_ms(); | |
384 } | |
385 | |
386 double predict_fully_young_cards_per_entry_ratio() { | |
387 return get_new_prediction(_fully_young_cards_per_entry_ratio_seq); | |
388 } | |
389 | |
390 double predict_partially_young_cards_per_entry_ratio() { | |
391 if (_partially_young_cards_per_entry_ratio_seq->num() < 2) | |
392 return predict_fully_young_cards_per_entry_ratio(); | |
393 else | |
394 return get_new_prediction(_partially_young_cards_per_entry_ratio_seq); | |
395 } | |
396 | |
397 size_t predict_young_card_num(size_t rs_length) { | |
398 return (size_t) ((double) rs_length * | |
399 predict_fully_young_cards_per_entry_ratio()); | |
400 } | |
401 | |
402 size_t predict_non_young_card_num(size_t rs_length) { | |
403 return (size_t) ((double) rs_length * | |
404 predict_partially_young_cards_per_entry_ratio()); | |
405 } | |
406 | |
407 double predict_rs_scan_time_ms(size_t card_num) { | |
408 if (full_young_gcs()) | |
409 return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq); | |
410 else | |
411 return predict_partially_young_rs_scan_time_ms(card_num); | |
412 } | |
413 | |
414 double predict_partially_young_rs_scan_time_ms(size_t card_num) { | |
415 if (_partially_young_cost_per_entry_ms_seq->num() < 3) | |
416 return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq); | |
417 else | |
418 return (double) card_num * | |
419 get_new_prediction(_partially_young_cost_per_entry_ms_seq); | |
420 } | |
421 | |
422 double predict_scan_only_time_ms_during_cm(size_t scan_only_region_num) { | |
423 if (_cost_per_scan_only_region_ms_during_cm_seq->num() < 3) | |
424 return 1.5 * (double) scan_only_region_num * | |
425 get_new_prediction(_cost_per_scan_only_region_ms_seq); | |
426 else | |
427 return (double) scan_only_region_num * | |
428 get_new_prediction(_cost_per_scan_only_region_ms_during_cm_seq); | |
429 } | |
430 | |
431 double predict_scan_only_time_ms(size_t scan_only_region_num) { | |
432 if (_in_marking_window_im) | |
433 return predict_scan_only_time_ms_during_cm(scan_only_region_num); | |
434 else | |
435 return (double) scan_only_region_num * | |
436 get_new_prediction(_cost_per_scan_only_region_ms_seq); | |
437 } | |
438 | |
439 double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) { | |
440 if (_cost_per_byte_ms_during_cm_seq->num() < 3) | |
441 return 1.1 * (double) bytes_to_copy * | |
442 get_new_prediction(_cost_per_byte_ms_seq); | |
443 else | |
444 return (double) bytes_to_copy * | |
445 get_new_prediction(_cost_per_byte_ms_during_cm_seq); | |
446 } | |
447 | |
448 double predict_object_copy_time_ms(size_t bytes_to_copy) { | |
449 if (_in_marking_window && !_in_marking_window_im) | |
450 return predict_object_copy_time_ms_during_cm(bytes_to_copy); | |
451 else | |
452 return (double) bytes_to_copy * | |
453 get_new_prediction(_cost_per_byte_ms_seq); | |
454 } | |
455 | |
456 double predict_constant_other_time_ms() { | |
457 return get_new_prediction(_constant_other_time_ms_seq); | |
458 } | |
459 | |
460 double predict_young_other_time_ms(size_t young_num) { | |
461 return | |
462 (double) young_num * | |
463 get_new_prediction(_young_other_cost_per_region_ms_seq); | |
464 } | |
465 | |
466 double predict_non_young_other_time_ms(size_t non_young_num) { | |
467 return | |
468 (double) non_young_num * | |
469 get_new_prediction(_non_young_other_cost_per_region_ms_seq); | |
470 } | |
471 | |
472 void check_if_region_is_too_expensive(double predicted_time_ms); | |
473 | |
474 double predict_young_collection_elapsed_time_ms(size_t adjustment); | |
475 double predict_base_elapsed_time_ms(size_t pending_cards); | |
476 double predict_base_elapsed_time_ms(size_t pending_cards, | |
477 size_t scanned_cards); | |
478 size_t predict_bytes_to_copy(HeapRegion* hr); | |
479 double predict_region_elapsed_time_ms(HeapRegion* hr, bool young); | |
480 | |
481 // for use by: calculate_optimal_so_length(length) | |
482 void predict_gc_eff(size_t young_region_num, | |
483 size_t so_length, | |
484 double base_time_ms, | |
485 double *gc_eff, | |
486 double *pause_time_ms); | |
487 | |
488 // for use by: calculate_young_list_target_config(rs_length) | |
489 bool predict_gc_eff(size_t young_region_num, | |
490 size_t so_length, | |
491 double base_time_with_so_ms, | |
492 size_t init_free_regions, | |
493 double target_pause_time_ms, | |
494 double* gc_eff); | |
495 | |
496 void start_recording_regions(); | |
497 void record_cset_region(HeapRegion* hr, bool young); | |
498 void record_scan_only_regions(size_t scan_only_length); | |
499 void end_recording_regions(); | |
500 | |
501 void record_vtime_diff_ms(double vtime_diff_ms) { | |
502 _vtime_diff_ms = vtime_diff_ms; | |
503 } | |
504 | |
505 void record_young_free_cset_time_ms(double time_ms) { | |
506 _recorded_young_free_cset_time_ms = time_ms; | |
507 } | |
508 | |
509 void record_non_young_free_cset_time_ms(double time_ms) { | |
510 _recorded_non_young_free_cset_time_ms = time_ms; | |
511 } | |
512 | |
513 double predict_young_gc_eff() { | |
514 return get_new_neg_prediction(_young_gc_eff_seq); | |
515 } | |
516 | |
545 | 517 double predict_survivor_regions_evac_time(); |
518 | |
342 | 519 // </NEW PREDICTION> |
520 | |
521 public: | |
522 void cset_regions_freed() { | |
523 bool propagate = _last_young_gc_full && !_in_marking_window; | |
524 _short_lived_surv_rate_group->all_surviving_words_recorded(propagate); | |
525 _survivor_surv_rate_group->all_surviving_words_recorded(propagate); | |
526 // also call it on any more surv rate groups | |
527 } | |
528 | |
529 void set_known_garbage_bytes(size_t known_garbage_bytes) { | |
530 _known_garbage_bytes = known_garbage_bytes; | |
531 size_t heap_bytes = _g1->capacity(); | |
532 _known_garbage_ratio = (double) _known_garbage_bytes / (double) heap_bytes; | |
533 } | |
534 | |
535 void decrease_known_garbage_bytes(size_t known_garbage_bytes) { | |
536 guarantee( _known_garbage_bytes >= known_garbage_bytes, "invariant" ); | |
537 | |
538 _known_garbage_bytes -= known_garbage_bytes; | |
539 size_t heap_bytes = _g1->capacity(); | |
540 _known_garbage_ratio = (double) _known_garbage_bytes / (double) heap_bytes; | |
541 } | |
542 | |
543 G1MMUTracker* mmu_tracker() { | |
544 return _mmu_tracker; | |
545 } | |
546 | |
547 double predict_init_time_ms() { | |
548 return get_new_prediction(_concurrent_mark_init_times_ms); | |
549 } | |
550 | |
551 double predict_remark_time_ms() { | |
552 return get_new_prediction(_concurrent_mark_remark_times_ms); | |
553 } | |
554 | |
555 double predict_cleanup_time_ms() { | |
556 return get_new_prediction(_concurrent_mark_cleanup_times_ms); | |
557 } | |
558 | |
559 // Returns an estimate of the survival rate of the region at yg-age | |
560 // "yg_age". | |
545 | 561 double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) { |
562 TruncatedSeq* seq = surv_rate_group->get_seq(age); | |
342 | 563 if (seq->num() == 0) |
564 gclog_or_tty->print("BARF! age is %d", age); | |
565 guarantee( seq->num() > 0, "invariant" ); | |
566 double pred = get_new_prediction(seq); | |
567 if (pred > 1.0) | |
568 pred = 1.0; | |
569 return pred; | |
570 } | |
571 | |
545 | 572 double predict_yg_surv_rate(int age) { |
573 return predict_yg_surv_rate(age, _short_lived_surv_rate_group); | |
574 } | |
575 | |
342 | 576 double accum_yg_surv_rate_pred(int age) { |
577 return _short_lived_surv_rate_group->accum_surv_rate_pred(age); | |
578 } | |
579 | |
580 protected: | |
581 void print_stats (int level, const char* str, double value); | |
582 void print_stats (int level, const char* str, int value); | |
583 void print_par_stats (int level, const char* str, double* data) { | |
584 print_par_stats(level, str, data, true); | |
585 } | |
586 void print_par_stats (int level, const char* str, double* data, bool summary); | |
587 void print_par_buffers (int level, const char* str, double* data, bool summary); | |
588 | |
589 void check_other_times(int level, | |
590 NumberSeq* other_times_ms, | |
591 NumberSeq* calc_other_times_ms) const; | |
592 | |
593 void print_summary (PauseSummary* stats) const; | |
677 | 594 void print_abandoned_summary(PauseSummary* summary) const; |
342 | 595 |
596 void print_summary (int level, const char* str, NumberSeq* seq) const; | |
597 void print_summary_sd (int level, const char* str, NumberSeq* seq) const; | |
598 | |
599 double avg_value (double* data); | |
600 double max_value (double* data); | |
601 double sum_of_values (double* data); | |
602 double max_sum (double* data1, double* data2); | |
603 | |
604 int _last_satb_drain_processed_buffers; | |
605 int _last_update_rs_processed_buffers; | |
606 double _last_pause_time_ms; | |
607 | |
608 size_t _bytes_in_to_space_before_gc; | |
609 size_t _bytes_in_to_space_after_gc; | |
610 size_t bytes_in_to_space_during_gc() { | |
611 return | |
612 _bytes_in_to_space_after_gc - _bytes_in_to_space_before_gc; | |
613 } | |
614 size_t _bytes_in_collection_set_before_gc; | |
615 // Used to count used bytes in CS. | |
616 friend class CountCSClosure; | |
617 | |
618 // Statistics kept per GC stoppage, pause or full. | |
619 TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec; | |
620 | |
621 // We track markings. | |
622 int _num_markings; | |
623 double _mark_thread_startup_sec; // Time at startup of marking thread | |
624 | |
625 // Add a new GC of the given duration and end time to the record. | |
626 void update_recent_gc_times(double end_time_sec, double elapsed_ms); | |
627 | |
628 // The head of the list (via "next_in_collection_set()") representing the | |
629 // current collection set. | |
630 HeapRegion* _collection_set; | |
631 size_t _collection_set_size; | |
632 size_t _collection_set_bytes_used_before; | |
633 | |
634 // Info about marking. | |
635 int _n_marks; // Sticky at 2, so we know when we've done at least 2. | |
636 | |
637 // The number of collection pauses at the end of the last mark. | |
638 size_t _n_pauses_at_mark_end; | |
639 | |
640 // Stash a pointer to the g1 heap. | |
641 G1CollectedHeap* _g1; | |
642 | |
643 // The average time in ms per collection pause, averaged over recent pauses. | |
644 double recent_avg_time_for_pauses_ms(); | |
645 | |
646 // The average time in ms for processing CollectedHeap strong roots, per | |
647 // collection pause, averaged over recent pauses. | |
648 double recent_avg_time_for_CH_strong_ms(); | |
649 | |
650 // The average time in ms for processing the G1 remembered set, per | |
651 // pause, averaged over recent pauses. | |
652 double recent_avg_time_for_G1_strong_ms(); | |
653 | |
654 // The average time in ms for "evacuating followers", per pause, averaged | |
655 // over recent pauses. | |
656 double recent_avg_time_for_evac_ms(); | |
657 | |
658 // The number of "recent" GCs recorded in the number sequences | |
659 int number_of_recent_gcs(); | |
660 | |
661 // The average survival ratio, computed by the total number of bytes | |
662 // suriviving / total number of bytes before collection over the last | |
663 // several recent pauses. | |
664 double recent_avg_survival_fraction(); | |
665 // The survival fraction of the most recent pause; if there have been no | |
666 // pauses, returns 1.0. | |
667 double last_survival_fraction(); | |
668 | |
669 // Returns a "conservative" estimate of the recent survival rate, i.e., | |
670 // one that may be higher than "recent_avg_survival_fraction". | |
671 // This is conservative in several ways: | |
672 // If there have been few pauses, it will assume a potential high | |
673 // variance, and err on the side of caution. | |
674 // It puts a lower bound (currently 0.1) on the value it will return. | |
675 // To try to detect phase changes, if the most recent pause ("latest") has a | |
676 // higher-than average ("avg") survival rate, it returns that rate. | |
677 // "work" version is a utility function; young is restricted to young regions. | |
678 double conservative_avg_survival_fraction_work(double avg, | |
679 double latest); | |
680 | |
681 // The arguments are the two sequences that keep track of the number of bytes | |
682 // surviving and the total number of bytes before collection, resp., | |
683 // over the last evereal recent pauses | |
684 // Returns the survival rate for the category in the most recent pause. | |
685 // If there have been no pauses, returns 1.0. | |
686 double last_survival_fraction_work(TruncatedSeq* surviving, | |
687 TruncatedSeq* before); | |
688 | |
689 // The arguments are the two sequences that keep track of the number of bytes | |
690 // surviving and the total number of bytes before collection, resp., | |
691 // over the last several recent pauses | |
692 // Returns the average survival ration over the last several recent pauses | |
693 // If there have been no pauses, return 1.0 | |
694 double recent_avg_survival_fraction_work(TruncatedSeq* surviving, | |
695 TruncatedSeq* before); | |
696 | |
697 double conservative_avg_survival_fraction() { | |
698 double avg = recent_avg_survival_fraction(); | |
699 double latest = last_survival_fraction(); | |
700 return conservative_avg_survival_fraction_work(avg, latest); | |
701 } | |
702 | |
703 // The ratio of gc time to elapsed time, computed over recent pauses. | |
704 double _recent_avg_pause_time_ratio; | |
705 | |
706 double recent_avg_pause_time_ratio() { | |
707 return _recent_avg_pause_time_ratio; | |
708 } | |
709 | |
710 // Number of pauses between concurrent marking. | |
711 size_t _pauses_btwn_concurrent_mark; | |
712 | |
713 size_t _n_marks_since_last_pause; | |
714 | |
715 // True iff CM has been initiated. | |
716 bool _conc_mark_initiated; | |
717 | |
718 // True iff CM should be initiated | |
719 bool _should_initiate_conc_mark; | |
720 bool _should_revert_to_full_young_gcs; | |
721 bool _last_full_young_gc; | |
722 | |
723 // This set of variables tracks the collector efficiency, in order to | |
724 // determine whether we should initiate a new marking. | |
725 double _cur_mark_stop_world_time_ms; | |
726 double _mark_init_start_sec; | |
727 double _mark_remark_start_sec; | |
728 double _mark_cleanup_start_sec; | |
729 double _mark_closure_time_ms; | |
730 | |
731 void calculate_young_list_min_length(); | |
732 void calculate_young_list_target_config(); | |
733 void calculate_young_list_target_config(size_t rs_lengths); | |
734 size_t calculate_optimal_so_length(size_t young_list_length); | |
735 | |
736 public: | |
737 | |
738 G1CollectorPolicy(); | |
739 | |
740 virtual G1CollectorPolicy* as_g1_policy() { return this; } | |
741 | |
742 virtual CollectorPolicy::Name kind() { | |
743 return CollectorPolicy::G1CollectorPolicyKind; | |
744 } | |
745 | |
746 void check_prediction_validity(); | |
747 | |
748 size_t bytes_in_collection_set() { | |
749 return _bytes_in_collection_set_before_gc; | |
750 } | |
751 | |
752 size_t bytes_in_to_space() { | |
753 return bytes_in_to_space_during_gc(); | |
754 } | |
755 | |
756 unsigned calc_gc_alloc_time_stamp() { | |
757 return _all_pause_times_ms->num() + 1; | |
758 } | |
759 | |
760 protected: | |
761 | |
762 // Count the number of bytes used in the CS. | |
763 void count_CS_bytes_used(); | |
764 | |
765 // Together these do the base cleanup-recording work. Subclasses might | |
766 // want to put something between them. | |
767 void record_concurrent_mark_cleanup_end_work1(size_t freed_bytes, | |
768 size_t max_live_bytes); | |
769 void record_concurrent_mark_cleanup_end_work2(); | |
770 | |
771 public: | |
772 | |
773 virtual void init(); | |
774 | |
545 | 775 // Create jstat counters for the policy. |
776 virtual void initialize_gc_policy_counters(); | |
777 | |
342 | 778 virtual HeapWord* mem_allocate_work(size_t size, |
779 bool is_tlab, | |
780 bool* gc_overhead_limit_was_exceeded); | |
781 | |
782 // This method controls how a collector handles one or more | |
783 // of its generations being fully allocated. | |
784 virtual HeapWord* satisfy_failed_allocation(size_t size, | |
785 bool is_tlab); | |
786 | |
787 BarrierSet::Name barrier_set_name() { return BarrierSet::G1SATBCTLogging; } | |
788 | |
789 GenRemSet::Name rem_set_name() { return GenRemSet::CardTable; } | |
790 | |
791 // The number of collection pauses so far. | |
792 long n_pauses() const { return _n_pauses; } | |
793 | |
794 // Update the heuristic info to record a collection pause of the given | |
795 // start time, where the given number of bytes were used at the start. | |
796 // This may involve changing the desired size of a collection set. | |
797 | |
798 virtual void record_stop_world_start(); | |
799 | |
800 virtual void record_collection_pause_start(double start_time_sec, | |
801 size_t start_used); | |
802 | |
803 // Must currently be called while the world is stopped. | |
804 virtual void record_concurrent_mark_init_start(); | |
805 virtual void record_concurrent_mark_init_end(); | |
806 void record_concurrent_mark_init_end_pre(double | |
807 mark_init_elapsed_time_ms); | |
808 | |
809 void record_mark_closure_time(double mark_closure_time_ms); | |
810 | |
811 virtual void record_concurrent_mark_remark_start(); | |
812 virtual void record_concurrent_mark_remark_end(); | |
813 | |
814 virtual void record_concurrent_mark_cleanup_start(); | |
815 virtual void record_concurrent_mark_cleanup_end(size_t freed_bytes, | |
816 size_t max_live_bytes); | |
817 virtual void record_concurrent_mark_cleanup_completed(); | |
818 | |
819 virtual void record_concurrent_pause(); | |
820 virtual void record_concurrent_pause_end(); | |
821 | |
822 virtual void record_collection_pause_end_CH_strong_roots(); | |
823 virtual void record_collection_pause_end_G1_strong_roots(); | |
824 | |
677 | 825 virtual void record_collection_pause_end(bool abandoned); |
342 | 826 |
827 // Record the fact that a full collection occurred. | |
828 virtual void record_full_collection_start(); | |
829 virtual void record_full_collection_end(); | |
830 | |
831 void record_ext_root_scan_time(int worker_i, double ms) { | |
832 _par_last_ext_root_scan_times_ms[worker_i] = ms; | |
833 } | |
834 | |
835 void record_mark_stack_scan_time(int worker_i, double ms) { | |
836 _par_last_mark_stack_scan_times_ms[worker_i] = ms; | |
837 } | |
838 | |
839 void record_scan_only_time(int worker_i, double ms, int n) { | |
840 _par_last_scan_only_times_ms[worker_i] = ms; | |
841 _par_last_scan_only_regions_scanned[worker_i] = (double) n; | |
842 } | |
843 | |
844 void record_satb_drain_time(double ms) { | |
845 _cur_satb_drain_time_ms = ms; | |
846 _satb_drain_time_set = true; | |
847 } | |
848 | |
849 void record_satb_drain_processed_buffers (int processed_buffers) { | |
850 _last_satb_drain_processed_buffers = processed_buffers; | |
851 } | |
852 | |
853 void record_mod_union_time(double ms) { | |
854 _all_mod_union_times_ms->add(ms); | |
855 } | |
856 | |
857 void record_update_rs_start_time(int thread, double ms) { | |
858 _par_last_update_rs_start_times_ms[thread] = ms; | |
859 } | |
860 | |
861 void record_update_rs_time(int thread, double ms) { | |
862 _par_last_update_rs_times_ms[thread] = ms; | |
863 } | |
864 | |
865 void record_update_rs_processed_buffers (int thread, | |
866 double processed_buffers) { | |
867 _par_last_update_rs_processed_buffers[thread] = processed_buffers; | |
868 } | |
869 | |
870 void record_scan_rs_start_time(int thread, double ms) { | |
871 _par_last_scan_rs_start_times_ms[thread] = ms; | |
872 } | |
873 | |
874 void record_scan_rs_time(int thread, double ms) { | |
875 _par_last_scan_rs_times_ms[thread] = ms; | |
876 } | |
877 | |
878 void record_scan_new_refs_time(int thread, double ms) { | |
879 _par_last_scan_new_refs_times_ms[thread] = ms; | |
880 } | |
881 | |
882 double get_scan_new_refs_time(int thread) { | |
883 return _par_last_scan_new_refs_times_ms[thread]; | |
884 } | |
885 | |
886 void reset_obj_copy_time(int thread) { | |
887 _par_last_obj_copy_times_ms[thread] = 0.0; | |
888 } | |
889 | |
890 void reset_obj_copy_time() { | |
891 reset_obj_copy_time(0); | |
892 } | |
893 | |
894 void record_obj_copy_time(int thread, double ms) { | |
895 _par_last_obj_copy_times_ms[thread] += ms; | |
896 } | |
897 | |
898 void record_obj_copy_time(double ms) { | |
899 record_obj_copy_time(0, ms); | |
900 } | |
901 | |
902 void record_termination_time(int thread, double ms) { | |
903 _par_last_termination_times_ms[thread] = ms; | |
904 } | |
905 | |
906 void record_termination_time(double ms) { | |
907 record_termination_time(0, ms); | |
908 } | |
909 | |
595
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910 void record_pause_time_ms(double ms) { |
342 | 911 _last_pause_time_ms = ms; |
912 } | |
913 | |
914 void record_clear_ct_time(double ms) { | |
915 _cur_clear_ct_time_ms = ms; | |
916 } | |
917 | |
918 void record_par_time(double ms) { | |
919 _cur_collection_par_time_ms = ms; | |
920 } | |
921 | |
922 void record_aux_start_time(int i) { | |
923 guarantee(i < _aux_num, "should be within range"); | |
924 _cur_aux_start_times_ms[i] = os::elapsedTime() * 1000.0; | |
925 } | |
926 | |
927 void record_aux_end_time(int i) { | |
928 guarantee(i < _aux_num, "should be within range"); | |
929 double ms = os::elapsedTime() * 1000.0 - _cur_aux_start_times_ms[i]; | |
930 _cur_aux_times_set[i] = true; | |
931 _cur_aux_times_ms[i] += ms; | |
932 } | |
933 | |
934 // Record the fact that "bytes" bytes allocated in a region. | |
935 void record_before_bytes(size_t bytes); | |
936 void record_after_bytes(size_t bytes); | |
937 | |
938 // Returns "true" if this is a good time to do a collection pause. | |
939 // The "word_size" argument, if non-zero, indicates the size of an | |
940 // allocation request that is prompting this query. | |
941 virtual bool should_do_collection_pause(size_t word_size) = 0; | |
942 | |
943 // Choose a new collection set. Marks the chosen regions as being | |
944 // "in_collection_set", and links them together. The head and number of | |
945 // the collection set are available via access methods. | |
677 | 946 virtual void choose_collection_set() = 0; |
342 | 947 |
948 void clear_collection_set() { _collection_set = NULL; } | |
949 | |
950 // The head of the list (via "next_in_collection_set()") representing the | |
951 // current collection set. | |
952 HeapRegion* collection_set() { return _collection_set; } | |
953 | |
954 // The number of elements in the current collection set. | |
955 size_t collection_set_size() { return _collection_set_size; } | |
956 | |
957 // Add "hr" to the CS. | |
958 void add_to_collection_set(HeapRegion* hr); | |
959 | |
960 bool should_initiate_conc_mark() { return _should_initiate_conc_mark; } | |
961 void set_should_initiate_conc_mark() { _should_initiate_conc_mark = true; } | |
962 void unset_should_initiate_conc_mark(){ _should_initiate_conc_mark = false; } | |
963 | |
964 void checkpoint_conc_overhead(); | |
965 | |
966 // If an expansion would be appropriate, because recent GC overhead had | |
967 // exceeded the desired limit, return an amount to expand by. | |
968 virtual size_t expansion_amount(); | |
969 | |
970 // note start of mark thread | |
971 void note_start_of_mark_thread(); | |
972 | |
973 // The marked bytes of the "r" has changed; reclassify it's desirability | |
974 // for marking. Also asserts that "r" is eligible for a CS. | |
975 virtual void note_change_in_marked_bytes(HeapRegion* r) = 0; | |
976 | |
977 #ifndef PRODUCT | |
978 // Check any appropriate marked bytes info, asserting false if | |
979 // something's wrong, else returning "true". | |
980 virtual bool assertMarkedBytesDataOK() = 0; | |
981 #endif | |
982 | |
983 // Print tracing information. | |
984 void print_tracing_info() const; | |
985 | |
986 // Print stats on young survival ratio | |
987 void print_yg_surv_rate_info() const; | |
988 | |
545 | 989 void finished_recalculating_age_indexes(bool is_survivors) { |
990 if (is_survivors) { | |
991 _survivor_surv_rate_group->finished_recalculating_age_indexes(); | |
992 } else { | |
993 _short_lived_surv_rate_group->finished_recalculating_age_indexes(); | |
994 } | |
342 | 995 // do that for any other surv rate groups |
996 } | |
997 | |
998 bool should_add_next_region_to_young_list(); | |
999 | |
1000 bool in_young_gc_mode() { | |
1001 return _in_young_gc_mode; | |
1002 } | |
1003 void set_in_young_gc_mode(bool in_young_gc_mode) { | |
1004 _in_young_gc_mode = in_young_gc_mode; | |
1005 } | |
1006 | |
1007 bool full_young_gcs() { | |
1008 return _full_young_gcs; | |
1009 } | |
1010 void set_full_young_gcs(bool full_young_gcs) { | |
1011 _full_young_gcs = full_young_gcs; | |
1012 } | |
1013 | |
1014 bool adaptive_young_list_length() { | |
1015 return _adaptive_young_list_length; | |
1016 } | |
1017 void set_adaptive_young_list_length(bool adaptive_young_list_length) { | |
1018 _adaptive_young_list_length = adaptive_young_list_length; | |
1019 } | |
1020 | |
1021 inline double get_gc_eff_factor() { | |
1022 double ratio = _known_garbage_ratio; | |
1023 | |
1024 double square = ratio * ratio; | |
1025 // square = square * square; | |
1026 double ret = square * 9.0 + 1.0; | |
1027 #if 0 | |
1028 gclog_or_tty->print_cr("ratio = %1.2lf, ret = %1.2lf", ratio, ret); | |
1029 #endif // 0 | |
1030 guarantee(0.0 <= ret && ret < 10.0, "invariant!"); | |
1031 return ret; | |
1032 } | |
1033 | |
1034 // | |
1035 // Survivor regions policy. | |
1036 // | |
1037 protected: | |
1038 | |
1039 // Current tenuring threshold, set to 0 if the collector reaches the | |
1040 // maximum amount of suvivors regions. | |
1041 int _tenuring_threshold; | |
1042 | |
545 | 1043 // The limit on the number of regions allocated for survivors. |
1044 size_t _max_survivor_regions; | |
1045 | |
1046 // The amount of survor regions after a collection. | |
1047 size_t _recorded_survivor_regions; | |
1048 // List of survivor regions. | |
1049 HeapRegion* _recorded_survivor_head; | |
1050 HeapRegion* _recorded_survivor_tail; | |
1051 | |
1052 ageTable _survivors_age_table; | |
1053 | |
342 | 1054 public: |
1055 | |
1056 inline GCAllocPurpose | |
1057 evacuation_destination(HeapRegion* src_region, int age, size_t word_sz) { | |
1058 if (age < _tenuring_threshold && src_region->is_young()) { | |
1059 return GCAllocForSurvived; | |
1060 } else { | |
1061 return GCAllocForTenured; | |
1062 } | |
1063 } | |
1064 | |
1065 inline bool track_object_age(GCAllocPurpose purpose) { | |
1066 return purpose == GCAllocForSurvived; | |
1067 } | |
1068 | |
1069 inline GCAllocPurpose alternative_purpose(int purpose) { | |
1070 return GCAllocForTenured; | |
1071 } | |
1072 | |
545 | 1073 static const size_t REGIONS_UNLIMITED = ~(size_t)0; |
1074 | |
1075 size_t max_regions(int purpose); | |
342 | 1076 |
1077 // The limit on regions for a particular purpose is reached. | |
1078 void note_alloc_region_limit_reached(int purpose) { | |
1079 if (purpose == GCAllocForSurvived) { | |
1080 _tenuring_threshold = 0; | |
1081 } | |
1082 } | |
1083 | |
1084 void note_start_adding_survivor_regions() { | |
1085 _survivor_surv_rate_group->start_adding_regions(); | |
1086 } | |
1087 | |
1088 void note_stop_adding_survivor_regions() { | |
1089 _survivor_surv_rate_group->stop_adding_regions(); | |
1090 } | |
545 | 1091 |
1092 void record_survivor_regions(size_t regions, | |
1093 HeapRegion* head, | |
1094 HeapRegion* tail) { | |
1095 _recorded_survivor_regions = regions; | |
1096 _recorded_survivor_head = head; | |
1097 _recorded_survivor_tail = tail; | |
1098 } | |
1099 | |
838
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1100 size_t recorded_survivor_regions() { |
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1101 return _recorded_survivor_regions; |
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1102 } |
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1103 |
545 | 1104 void record_thread_age_table(ageTable* age_table) |
1105 { | |
1106 _survivors_age_table.merge_par(age_table); | |
1107 } | |
1108 | |
1109 // Calculates survivor space parameters. | |
1110 void calculate_survivors_policy(); | |
1111 | |
342 | 1112 }; |
1113 | |
1114 // This encapsulates a particular strategy for a g1 Collector. | |
1115 // | |
1116 // Start a concurrent mark when our heap size is n bytes | |
1117 // greater then our heap size was at the last concurrent | |
1118 // mark. Where n is a function of the CMSTriggerRatio | |
1119 // and the MinHeapFreeRatio. | |
1120 // | |
1121 // Start a g1 collection pause when we have allocated the | |
1122 // average number of bytes currently being freed in | |
1123 // a collection, but only if it is at least one region | |
1124 // full | |
1125 // | |
1126 // Resize Heap based on desired | |
1127 // allocation space, where desired allocation space is | |
1128 // a function of survival rate and desired future to size. | |
1129 // | |
1130 // Choose collection set by first picking all older regions | |
1131 // which have a survival rate which beats our projected young | |
1132 // survival rate. Then fill out the number of needed regions | |
1133 // with young regions. | |
1134 | |
1135 class G1CollectorPolicy_BestRegionsFirst: public G1CollectorPolicy { | |
1136 CollectionSetChooser* _collectionSetChooser; | |
1137 // If the estimated is less then desirable, resize if possible. | |
1138 void expand_if_possible(size_t numRegions); | |
1139 | |
677 | 1140 virtual void choose_collection_set(); |
342 | 1141 virtual void record_collection_pause_start(double start_time_sec, |
1142 size_t start_used); | |
1143 virtual void record_concurrent_mark_cleanup_end(size_t freed_bytes, | |
1144 size_t max_live_bytes); | |
1145 virtual void record_full_collection_end(); | |
1146 | |
1147 public: | |
1148 G1CollectorPolicy_BestRegionsFirst() { | |
1149 _collectionSetChooser = new CollectionSetChooser(); | |
1150 } | |
677 | 1151 void record_collection_pause_end(bool abandoned); |
342 | 1152 bool should_do_collection_pause(size_t word_size); |
1153 // This is not needed any more, after the CSet choosing code was | |
1154 // changed to use the pause prediction work. But let's leave the | |
1155 // hook in just in case. | |
1156 void note_change_in_marked_bytes(HeapRegion* r) { } | |
1157 #ifndef PRODUCT | |
1158 bool assertMarkedBytesDataOK(); | |
1159 #endif | |
1160 }; | |
1161 | |
1162 // This should move to some place more general... | |
1163 | |
1164 // If we have "n" measurements, and we've kept track of their "sum" and the | |
1165 // "sum_of_squares" of the measurements, this returns the variance of the | |
1166 // sequence. | |
1167 inline double variance(int n, double sum_of_squares, double sum) { | |
1168 double n_d = (double)n; | |
1169 double avg = sum/n_d; | |
1170 return (sum_of_squares - 2.0 * avg * sum + n_d * avg * avg) / n_d; | |
1171 } | |
1172 | |
1173 // Local Variables: *** | |
1174 // c-indentation-style: gnu *** | |
1175 // End: *** |