1/*
2 * Copyright (c) 2016, 2018, 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/os.hpp"
29#include "utilities/debug.hpp"
30#include "utilities/numberSeq.hpp"
31
32// Different defaults for different number of GC threads
33// They were chosen by running GCOld and SPECjbb on debris with different
34// numbers of GC threads and choosing them based on the results
35
36// all the same
37static double rs_length_diff_defaults[] = {
38 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
39};
40
41static double cost_per_card_ms_defaults[] = {
42 0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
43};
44
45// all the same
46static double young_cards_per_entry_ratio_defaults[] = {
47 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
48};
49
50static double cost_per_entry_ms_defaults[] = {
51 0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
52};
53
54static double cost_per_byte_ms_defaults[] = {
55 0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
56};
57
58// these should be pretty consistent
59static double constant_other_time_ms_defaults[] = {
60 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
61};
62
63
64static double young_other_cost_per_region_ms_defaults[] = {
65 0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
66};
67
68static double non_young_other_cost_per_region_ms_defaults[] = {
69 1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
70};
71
72G1Analytics::G1Analytics(const G1Predictions* predictor) :
73 _predictor(predictor),
74 _recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
75 _concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
76 _concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
77 _alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
78 _prev_collection_pause_end_ms(0.0),
79 _rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
80 _cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
81 _cost_scan_hcc_seq(new TruncatedSeq(TruncatedSeqLength)),
82 _young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
83 _mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
84 _cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
85 _mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
86 _cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
87 _constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
88 _young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
89 _non_young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
90 _pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
91 _rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
92 _cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
93 _recent_prev_end_times_for_all_gcs_sec(new TruncatedSeq(NumPrevPausesForHeuristics)),
94 _recent_avg_pause_time_ratio(0.0),
95 _last_pause_time_ratio(0.0) {
96
97 // Seed sequences with initial values.
98 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
99 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
100
101 int index = MIN2(ParallelGCThreads - 1, 7u);
102
103 _rs_length_diff_seq->add(rs_length_diff_defaults[index]);
104 _cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
105 _cost_scan_hcc_seq->add(0.0);
106 _young_cards_per_entry_ratio_seq->add(young_cards_per_entry_ratio_defaults[index]);
107 _cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
108 _cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
109 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
110 _young_other_cost_per_region_ms_seq->add(young_other_cost_per_region_ms_defaults[index]);
111 _non_young_other_cost_per_region_ms_seq->add(non_young_other_cost_per_region_ms_defaults[index]);
112
113 // start conservatively (around 50ms is about right)
114 _concurrent_mark_remark_times_ms->add(0.05);
115 _concurrent_mark_cleanup_times_ms->add(0.20);
116}
117
118double G1Analytics::get_new_prediction(TruncatedSeq const* seq) const {
119 return _predictor->get_new_prediction(seq);
120}
121
122size_t G1Analytics::get_new_size_prediction(TruncatedSeq const* seq) const {
123 return (size_t)get_new_prediction(seq);
124}
125
126int G1Analytics::num_alloc_rate_ms() const {
127 return _alloc_rate_ms_seq->num();
128}
129
130void G1Analytics::report_concurrent_mark_remark_times_ms(double ms) {
131 _concurrent_mark_remark_times_ms->add(ms);
132}
133
134void G1Analytics::report_alloc_rate_ms(double alloc_rate) {
135 _alloc_rate_ms_seq->add(alloc_rate);
136}
137
138void G1Analytics::compute_pause_time_ratio(double interval_ms, double pause_time_ms) {
139 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum() / interval_ms;
140 if (_recent_avg_pause_time_ratio < 0.0 ||
141 (_recent_avg_pause_time_ratio - 1.0 > 0.0)) {
142 // Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
143 // CR 6902692 by redoing the manner in which the ratio is incrementally computed.
144 if (_recent_avg_pause_time_ratio < 0.0) {
145 _recent_avg_pause_time_ratio = 0.0;
146 } else {
147 assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
148 _recent_avg_pause_time_ratio = 1.0;
149 }
150 }
151
152 // Compute the ratio of just this last pause time to the entire time range stored
153 // in the vectors. Comparing this pause to the entire range, rather than only the
154 // most recent interval, has the effect of smoothing over a possible transient 'burst'
155 // of more frequent pauses that don't really reflect a change in heap occupancy.
156 // This reduces the likelihood of a needless heap expansion being triggered.
157 _last_pause_time_ratio =
158 (pause_time_ms * _recent_prev_end_times_for_all_gcs_sec->num()) / interval_ms;
159}
160
161void G1Analytics::report_cost_per_card_ms(double cost_per_card_ms) {
162 _cost_per_card_ms_seq->add(cost_per_card_ms);
163}
164
165void G1Analytics::report_cost_scan_hcc(double cost_scan_hcc) {
166 _cost_scan_hcc_seq->add(cost_scan_hcc);
167}
168
169void G1Analytics::report_cost_per_entry_ms(double cost_per_entry_ms, bool for_young_gc) {
170 if (for_young_gc) {
171 _cost_per_entry_ms_seq->add(cost_per_entry_ms);
172 } else {
173 _mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
174 }
175}
176
177void G1Analytics::report_cards_per_entry_ratio(double cards_per_entry_ratio, bool for_young_gc) {
178 if (for_young_gc) {
179 _young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
180 } else {
181 _mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
182 }
183}
184
185void G1Analytics::report_rs_length_diff(double rs_length_diff) {
186 _rs_length_diff_seq->add(rs_length_diff);
187}
188
189void G1Analytics::report_cost_per_byte_ms(double cost_per_byte_ms, bool mark_or_rebuild_in_progress) {
190 if (mark_or_rebuild_in_progress) {
191 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
192 } else {
193 _cost_per_byte_ms_seq->add(cost_per_byte_ms);
194 }
195}
196
197void G1Analytics::report_young_other_cost_per_region_ms(double other_cost_per_region_ms) {
198 _young_other_cost_per_region_ms_seq->add(other_cost_per_region_ms);
199}
200
201void G1Analytics::report_non_young_other_cost_per_region_ms(double other_cost_per_region_ms) {
202 _non_young_other_cost_per_region_ms_seq->add(other_cost_per_region_ms);
203}
204
205void G1Analytics::report_constant_other_time_ms(double constant_other_time_ms) {
206 _constant_other_time_ms_seq->add(constant_other_time_ms);
207}
208
209void G1Analytics::report_pending_cards(double pending_cards) {
210 _pending_cards_seq->add(pending_cards);
211}
212
213void G1Analytics::report_rs_lengths(double rs_lengths) {
214 _rs_lengths_seq->add(rs_lengths);
215}
216
217size_t G1Analytics::predict_rs_length_diff() const {
218 return get_new_size_prediction(_rs_length_diff_seq);
219}
220
221double G1Analytics::predict_alloc_rate_ms() const {
222 return get_new_prediction(_alloc_rate_ms_seq);
223}
224
225double G1Analytics::predict_cost_per_card_ms() const {
226 return get_new_prediction(_cost_per_card_ms_seq);
227}
228
229double G1Analytics::predict_scan_hcc_ms() const {
230 return get_new_prediction(_cost_scan_hcc_seq);
231}
232
233double G1Analytics::predict_rs_update_time_ms(size_t pending_cards) const {
234 return pending_cards * predict_cost_per_card_ms() + predict_scan_hcc_ms();
235}
236
237double G1Analytics::predict_young_cards_per_entry_ratio() const {
238 return get_new_prediction(_young_cards_per_entry_ratio_seq);
239}
240
241double G1Analytics::predict_mixed_cards_per_entry_ratio() const {
242 if (_mixed_cards_per_entry_ratio_seq->num() < 2) {
243 return predict_young_cards_per_entry_ratio();
244 } else {
245 return get_new_prediction(_mixed_cards_per_entry_ratio_seq);
246 }
247}
248
249size_t G1Analytics::predict_card_num(size_t rs_length, bool for_young_gc) const {
250 if (for_young_gc) {
251 return (size_t) (rs_length * predict_young_cards_per_entry_ratio());
252 } else {
253 return (size_t) (rs_length * predict_mixed_cards_per_entry_ratio());
254 }
255}
256
257double G1Analytics::predict_rs_scan_time_ms(size_t card_num, bool for_young_gc) const {
258 if (for_young_gc) {
259 return card_num * get_new_prediction(_cost_per_entry_ms_seq);
260 } else {
261 return predict_mixed_rs_scan_time_ms(card_num);
262 }
263}
264
265double G1Analytics::predict_mixed_rs_scan_time_ms(size_t card_num) const {
266 if (_mixed_cost_per_entry_ms_seq->num() < 3) {
267 return card_num * get_new_prediction(_cost_per_entry_ms_seq);
268 } else {
269 return card_num * get_new_prediction(_mixed_cost_per_entry_ms_seq);
270 }
271}
272
273double G1Analytics::predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const {
274 if (_cost_per_byte_ms_during_cm_seq->num() < 3) {
275 return (1.1 * bytes_to_copy) * get_new_prediction(_cost_per_byte_ms_seq);
276 } else {
277 return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_during_cm_seq);
278 }
279}
280
281double G1Analytics::predict_object_copy_time_ms(size_t bytes_to_copy, bool during_concurrent_mark) const {
282 if (during_concurrent_mark) {
283 return predict_object_copy_time_ms_during_cm(bytes_to_copy);
284 } else {
285 return bytes_to_copy * get_new_prediction(_cost_per_byte_ms_seq);
286 }
287}
288
289double G1Analytics::predict_cost_per_byte_ms() const {
290 return get_new_prediction(_cost_per_byte_ms_seq);
291}
292
293double G1Analytics::predict_constant_other_time_ms() const {
294 return get_new_prediction(_constant_other_time_ms_seq);
295}
296
297double G1Analytics::predict_young_other_time_ms(size_t young_num) const {
298 return young_num * get_new_prediction(_young_other_cost_per_region_ms_seq);
299}
300
301double G1Analytics::predict_non_young_other_time_ms(size_t non_young_num) const {
302 return non_young_num * get_new_prediction(_non_young_other_cost_per_region_ms_seq);
303}
304
305double G1Analytics::predict_remark_time_ms() const {
306 return get_new_prediction(_concurrent_mark_remark_times_ms);
307}
308
309double G1Analytics::predict_cleanup_time_ms() const {
310 return get_new_prediction(_concurrent_mark_cleanup_times_ms);
311}
312
313size_t G1Analytics::predict_rs_lengths() const {
314 return get_new_size_prediction(_rs_lengths_seq);
315}
316
317size_t G1Analytics::predict_pending_cards() const {
318 return get_new_size_prediction(_pending_cards_seq);
319}
320
321double G1Analytics::last_known_gc_end_time_sec() const {
322 return _recent_prev_end_times_for_all_gcs_sec->oldest();
323}
324
325void G1Analytics::update_recent_gc_times(double end_time_sec,
326 double pause_time_ms) {
327 _recent_gc_times_ms->add(pause_time_ms);
328 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
329 _prev_collection_pause_end_ms = end_time_sec * 1000.0;
330}
331
332void G1Analytics::report_concurrent_mark_cleanup_times_ms(double ms) {
333 _concurrent_mark_cleanup_times_ms->add(ms);
334}
335