1 /*
2 * Copyright (c) 2016, 2020, 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 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/g1Analytics.hpp"
27 #include "gc/g1/g1Predictions.hpp"
28 #include "runtime/globals.hpp"
29 #include "runtime/os.hpp"
30 #include "utilities/debug.hpp"
31 #include "utilities/globalDefinitions.hpp"
32 #include "utilities/numberSeq.hpp"
33
34 // Different defaults for different number of GC threads
35 // They were chosen by running GCOld and SPECjbb on debris with different
36 // numbers of GC threads and choosing them based on the results
37
38 // all the same
39 static double rs_length_diff_defaults[] = {
40 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
41 };
42
43 static double cost_per_logged_card_ms_defaults[] = {
44 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
45 };
46
47 // all the same
48 static double young_card_merge_to_scan_ratio_defaults[] = {
49 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
50 };
51
52 static double young_only_cost_per_card_scan_ms_defaults[] = {
53 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
54 };
55
56 static double cost_per_byte_ms_defaults[] = {
57 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
58 };
59
60 // these should be pretty consistent
61 static double constant_other_time_ms_defaults[] = {
62 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
63 };
64
65 static double young_other_cost_per_region_ms_defaults[] = {
66 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
67 };
68
69 static double non_young_other_cost_per_region_ms_defaults[] = {
70 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
71 };
72
73 G1Analytics::G1Analytics(const G1Predictions* predictor) :
74 _predictor(predictor),
75 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
76 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
77 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
78 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
79 _prev_collection_pause_end_ms(0.0),
80 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
81 _concurrent_refine_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
82 _dirtied_cards_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
83 _young_card_merge_to_scan_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
84 _mixed_card_merge_to_scan_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
85 _young_cost_per_card_scan_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
86 _mixed_cost_per_card_scan_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
87 _young_cost_per_card_merge_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
88 _mixed_cost_per_card_merge_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
89 _copy_cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
90 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
91 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
92 _non_young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
93 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
94 _rs_length_seq(new TruncatedSeq(TruncatedSeqLength)),
95 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
96 _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
97 _long_term_pause_time_ratio(0.0),
98 _short_term_pause_time_ratio(0.0) {
99
100 // Seed sequences with initial values.
101 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
102 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
103
104 int index = MIN2(ParallelGCThreads - 1, 7u);
105
106 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
107 // Start with inverse of maximum STW cost.
108 _concurrent_refine_rate_ms_seq->add(1/cost_per_logged_card_ms_defaults[0]);
109 // Some applications have very low rates for logging cards.
110 _dirtied_cards_rate_ms_seq->add(0.0);
111 _young_card_merge_to_scan_ratio_seq->add(young_card_merge_to_scan_ratio_defaults[index]);
112 _young_cost_per_card_scan_ms_seq->add(young_only_cost_per_card_scan_ms_defaults[index]);
113
114 _copy_cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
115 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
116 _young_other_cost_per_region_ms_seq->add(young_other_cost_per_region_ms_defaults[index]);
117 _non_young_other_cost_per_region_ms_seq->add(non_young_other_cost_per_region_ms_defaults[index]);
118
119 // start conservatively (around 50ms is about right)
120 _concurrent_mark_remark_times_ms->add(0.05);
121 _concurrent_mark_cleanup_times_ms->add(0.20);
122 }
123
124 bool G1Analytics::enough_samples_available(TruncatedSeq const* seq) const {
125 return seq->num() >= 3;
126 }
127
128 double G1Analytics::predict_in_unit_interval(TruncatedSeq const* seq) const {
129 return _predictor->predict_in_unit_interval(seq);
130 }
131
132 size_t G1Analytics::predict_size(TruncatedSeq const* seq) const {
133 return (size_t)predict_zero_bounded(seq);
134 }
135
136 double G1Analytics::predict_zero_bounded(TruncatedSeq const* seq) const {
137 return _predictor->predict_zero_bounded(seq);
138 }
139
140 int G1Analytics::num_alloc_rate_ms() const {
141 return _alloc_rate_ms_seq->num();
142 }
143
144 void G1Analytics::report_concurrent_mark_remark_times_ms(double ms) {
145 _concurrent_mark_remark_times_ms->add(ms);
146 }
147
148 void G1Analytics::report_alloc_rate_ms(double alloc_rate) {
149 _alloc_rate_ms_seq->add(alloc_rate);
150 }
151
152 void G1Analytics::compute_pause_time_ratio(double interval_ms, double pause_time_ms) {
153 _long_term_pause_time_ratio = _recent_gc_times_ms->sum() / interval_ms;
154 // Filter out nonsensical results due to bad input.
155 _long_term_pause_time_ratio = clamp(_long_term_pause_time_ratio, 0.0, 1.0);
156
157 // Compute the ratio of just this last pause time to the entire time range stored
158 // in the vectors. Comparing this pause to the entire range, rather than only the
159 // most recent interval, has the effect of smoothing over a possible transient 'burst'
160 // of more frequent pauses that don't really reflect a change in heap occupancy.
161 // This reduces the likelihood of a needless heap expansion being triggered.
162 _short_term_pause_time_ratio =
163 (pause_time_ms * _recent_prev_end_times_for_all_gcs_sec->num()) / interval_ms;
164 }
165
166 void G1Analytics::report_concurrent_refine_rate_ms(double cards_per_ms) {
167 _concurrent_refine_rate_ms_seq->add(cards_per_ms);
168 }
169
170 void G1Analytics::report_dirtied_cards_rate_ms(double cards_per_ms) {
171 _dirtied_cards_rate_ms_seq->add(cards_per_ms);
172 }
173
174 void G1Analytics::report_cost_per_card_scan_ms(double cost_per_card_ms, bool for_young_gc) {
175 if (for_young_gc) {
176 _young_cost_per_card_scan_ms_seq->add(cost_per_card_ms);
177 } else {
178 _mixed_cost_per_card_scan_ms_seq->add(cost_per_card_ms);
179 }
180 }
181
182 void G1Analytics::report_cost_per_card_merge_ms(double cost_per_card_ms, bool for_young_gc) {
183 if (for_young_gc) {
184 _young_cost_per_card_merge_ms_seq->add(cost_per_card_ms);
185 } else {
186 _mixed_cost_per_card_merge_ms_seq->add(cost_per_card_ms);
187 }
188 }
189
190 void G1Analytics::report_card_merge_to_scan_ratio(double merge_to_scan_ratio, bool for_young_gc) {
191 if (for_young_gc) {
192 _young_card_merge_to_scan_ratio_seq->add(merge_to_scan_ratio);
193 } else {
194 _mixed_card_merge_to_scan_ratio_seq->add(merge_to_scan_ratio);
195 }
196 }
197
198 void G1Analytics::report_rs_length_diff(double rs_length_diff) {
199 _rs_length_diff_seq->add(rs_length_diff);
200 }
201
202 void G1Analytics::report_cost_per_byte_ms(double cost_per_byte_ms, bool mark_or_rebuild_in_progress) {
203 if (mark_or_rebuild_in_progress) {
204 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
205 } else {
206 _copy_cost_per_byte_ms_seq->add(cost_per_byte_ms);
207 }
208 }
209
210 void G1Analytics::report_young_other_cost_per_region_ms(double other_cost_per_region_ms) {
211 _young_other_cost_per_region_ms_seq->add(other_cost_per_region_ms);
212 }
213
214 void G1Analytics::report_non_young_other_cost_per_region_ms(double other_cost_per_region_ms) {
215 _non_young_other_cost_per_region_ms_seq->add(other_cost_per_region_ms);
216 }
217
218 void G1Analytics::report_constant_other_time_ms(double constant_other_time_ms) {
219 _constant_other_time_ms_seq->add(constant_other_time_ms);
220 }
221
222 void G1Analytics::report_pending_cards(double pending_cards) {
223 _pending_cards_seq->add(pending_cards);
224 }
225
226 void G1Analytics::report_rs_length(double rs_length) {
227 _rs_length_seq->add(rs_length);
228 }
229
230 double G1Analytics::predict_alloc_rate_ms() const {
231 return predict_zero_bounded(_alloc_rate_ms_seq);
232 }
233
234 double G1Analytics::predict_concurrent_refine_rate_ms() const {
235 return predict_zero_bounded(_concurrent_refine_rate_ms_seq);
236 }
237
238 double G1Analytics::predict_dirtied_cards_rate_ms() const {
239 return predict_zero_bounded(_dirtied_cards_rate_ms_seq);
240 }
241
242 double G1Analytics::predict_young_card_merge_to_scan_ratio() const {
243 return predict_in_unit_interval(_young_card_merge_to_scan_ratio_seq);
244 }
245
246 size_t G1Analytics::predict_scan_card_num(size_t rs_length, bool for_young_gc) const {
247 if (for_young_gc || !enough_samples_available(_mixed_card_merge_to_scan_ratio_seq)) {
248 return (size_t)(rs_length * predict_young_card_merge_to_scan_ratio());
249 } else {
250 return (size_t)(rs_length * predict_in_unit_interval(_mixed_card_merge_to_scan_ratio_seq));
251 }
252 }
253
254 double G1Analytics::predict_card_merge_time_ms(size_t card_num, bool for_young_gc) const {
255 if (for_young_gc || !enough_samples_available(_mixed_cost_per_card_merge_ms_seq)) {
256 return card_num * predict_zero_bounded(_young_cost_per_card_merge_ms_seq);
257 } else {
258 return card_num * predict_zero_bounded(_mixed_cost_per_card_merge_ms_seq);
259 }
260 }
261
262 double G1Analytics::predict_card_scan_time_ms(size_t card_num, bool for_young_gc) const {
263 if (for_young_gc || !enough_samples_available(_mixed_cost_per_card_scan_ms_seq)) {
264 return card_num * predict_zero_bounded(_young_cost_per_card_scan_ms_seq);
265 } else {
266 return card_num * predict_zero_bounded(_mixed_cost_per_card_scan_ms_seq);
267 }
268 }
269
270 double G1Analytics::predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const {
271 if (!enough_samples_available(_cost_per_byte_ms_during_cm_seq)) {
272 return (1.1 * bytes_to_copy) * predict_zero_bounded(_copy_cost_per_byte_ms_seq);
273 } else {
274 return bytes_to_copy * predict_zero_bounded(_cost_per_byte_ms_during_cm_seq);
275 }
276 }
277
278 double G1Analytics::predict_object_copy_time_ms(size_t bytes_to_copy, bool during_concurrent_mark) const {
279 if (during_concurrent_mark) {
280 return predict_object_copy_time_ms_during_cm(bytes_to_copy);
281 } else {
282 return bytes_to_copy * predict_zero_bounded(_copy_cost_per_byte_ms_seq);
283 }
284 }
285
286 double G1Analytics::predict_constant_other_time_ms() const {
287 return predict_zero_bounded(_constant_other_time_ms_seq);
288 }
289
290 double G1Analytics::predict_young_other_time_ms(size_t young_num) const {
291 return young_num * predict_zero_bounded(_young_other_cost_per_region_ms_seq);
292 }
293
294 double G1Analytics::predict_non_young_other_time_ms(size_t non_young_num) const {
295 return non_young_num * predict_zero_bounded(_non_young_other_cost_per_region_ms_seq);
296 }
297
298 double G1Analytics::predict_remark_time_ms() const {
299 return predict_zero_bounded(_concurrent_mark_remark_times_ms);
300 }
301
302 double G1Analytics::predict_cleanup_time_ms() const {
303 return predict_zero_bounded(_concurrent_mark_cleanup_times_ms);
304 }
305
306 size_t G1Analytics::predict_rs_length() const {
307 return predict_size(_rs_length_seq) + predict_size(_rs_length_diff_seq);
308 }
309
310 size_t G1Analytics::predict_pending_cards() const {
311 return predict_size(_pending_cards_seq);
312 }
313
314 double G1Analytics::last_known_gc_end_time_sec() const {
315 return _recent_prev_end_times_for_all_gcs_sec->oldest();
316 }
317
318 void G1Analytics::update_recent_gc_times(double end_time_sec,
319 double pause_time_ms) {
320 _recent_gc_times_ms->add(pause_time_ms);
321 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
322 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
323 }
324
325 void G1Analytics::report_concurrent_mark_cleanup_times_ms(double ms) {
326 _concurrent_mark_cleanup_times_ms->add(ms);
327 }