1 /* 2 * Copyright (c) 2016, 2019, 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 _logged_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 _survivor_ratio(new TruncatedSeq(TruncatedSeqLength)), 98 _recent_avg_pause_time_ratio(0.0), 99 _last_pause_time_ratio(0.0) { 100 101 // Seed sequences with initial values. 102 _recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime()); 103 _prev_collection_pause_end_ms = os::elapsedTime() * 1000.0; 104 105 int index = MIN2(ParallelGCThreads - 1, 7u); 106 107 _rs_length_diff_seq->add(rs_length_diff_defaults[index]); 108 // Start with inverse of maximum STW cost. 109 _concurrent_refine_rate_ms_seq->add(1/cost_per_logged_card_ms_defaults[0]); 110 // Some applications have very low rates for logging cards. 111 _logged_cards_rate_ms_seq->add(0.0); 112 _young_card_merge_to_scan_ratio_seq->add(young_card_merge_to_scan_ratio_defaults[index]); 113 _young_cost_per_card_scan_ms_seq->add(young_only_cost_per_card_scan_ms_defaults[index]); 114 115 _copy_cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]); 116 _constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]); 117 _young_other_cost_per_region_ms_seq->add(young_other_cost_per_region_ms_defaults[index]); 118 _non_young_other_cost_per_region_ms_seq->add(non_young_other_cost_per_region_ms_defaults[index]); 119 120 // start conservatively (around 50ms is about right) 121 _concurrent_mark_remark_times_ms->add(0.05); 122 _concurrent_mark_cleanup_times_ms->add(0.20); 123 124 _survivor_ratio->add(0.5); 125 } 126 127 bool G1Analytics::enough_samples_available(TruncatedSeq const* seq) const { 128 return seq->num() >= 3; 129 } 130 131 double G1Analytics::predict_in_unit_interval(TruncatedSeq const* seq) const { 132 return _predictor->predict_in_unit_interval(seq); 133 } 134 135 size_t G1Analytics::predict_size(TruncatedSeq const* seq) const { 136 return (size_t)predict_zero_bounded(seq); 137 } 138 139 double G1Analytics::predict_zero_bounded(TruncatedSeq const* seq) const { 140 return _predictor->predict_zero_bounded(seq); 141 } 142 143 int G1Analytics::num_alloc_rate_ms() const { 144 return _alloc_rate_ms_seq->num(); 145 } 146 147 void G1Analytics::report_concurrent_mark_remark_times_ms(double ms) { 148 _concurrent_mark_remark_times_ms->add(ms); 149 } 150 151 void G1Analytics::report_alloc_rate_ms(double alloc_rate) { 152 _alloc_rate_ms_seq->add(alloc_rate); 153 } 154 155 void G1Analytics::compute_pause_time_ratio(double interval_ms, double pause_time_ms) { 156 _recent_avg_pause_time_ratio = _recent_gc_times_ms->sum() / interval_ms; 157 158 // Clamp the result to [0.0 ... 1.0] to filter out nonsensical results due to bad input. 159 _recent_avg_pause_time_ratio = clamp(_recent_avg_pause_time_ratio, 0.0, 1.0); 160 161 // Compute the ratio of just this last pause time to the entire time range stored 162 // in the vectors. Comparing this pause to the entire range, rather than only the 163 // most recent interval, has the effect of smoothing over a possible transient 'burst' 164 // of more frequent pauses that don't really reflect a change in heap occupancy. 165 // This reduces the likelihood of a needless heap expansion being triggered. 166 _last_pause_time_ratio = 167 (pause_time_ms * _recent_prev_end_times_for_all_gcs_sec->num()) / interval_ms; 168 } 169 170 void G1Analytics::report_concurrent_refine_rate_ms(double cards_per_ms) { 171 _concurrent_refine_rate_ms_seq->add(cards_per_ms); 172 } 173 174 void G1Analytics::report_logged_cards_rate_ms(double cards_per_ms) { 175 _logged_cards_rate_ms_seq->add(cards_per_ms); 176 } 177 178 void G1Analytics::report_cost_per_card_scan_ms(double cost_per_card_ms, bool for_young_gc) { 179 if (for_young_gc) { 180 _young_cost_per_card_scan_ms_seq->add(cost_per_card_ms); 181 } else { 182 _mixed_cost_per_card_scan_ms_seq->add(cost_per_card_ms); 183 } 184 } 185 186 void G1Analytics::report_cost_per_card_merge_ms(double cost_per_card_ms, bool for_young_gc) { 187 if (for_young_gc) { 188 _young_cost_per_card_merge_ms_seq->add(cost_per_card_ms); 189 } else { 190 _mixed_cost_per_card_merge_ms_seq->add(cost_per_card_ms); 191 } 192 } 193 194 void G1Analytics::report_card_merge_to_scan_ratio(double merge_to_scan_ratio, bool for_young_gc) { 195 if (for_young_gc) { 196 _young_card_merge_to_scan_ratio_seq->add(merge_to_scan_ratio); 197 } else { 198 _mixed_card_merge_to_scan_ratio_seq->add(merge_to_scan_ratio); 199 } 200 } 201 202 void G1Analytics::report_rs_length_diff(double rs_length_diff) { 203 _rs_length_diff_seq->add(rs_length_diff); 204 } 205 206 void G1Analytics::report_cost_per_byte_ms(double cost_per_byte_ms, bool mark_or_rebuild_in_progress) { 207 if (mark_or_rebuild_in_progress) { 208 _cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms); 209 } else { 210 _copy_cost_per_byte_ms_seq->add(cost_per_byte_ms); 211 } 212 } 213 214 void G1Analytics::report_young_other_cost_per_region_ms(double other_cost_per_region_ms) { 215 _young_other_cost_per_region_ms_seq->add(other_cost_per_region_ms); 216 } 217 218 void G1Analytics::report_non_young_other_cost_per_region_ms(double other_cost_per_region_ms) { 219 _non_young_other_cost_per_region_ms_seq->add(other_cost_per_region_ms); 220 } 221 222 void G1Analytics::report_constant_other_time_ms(double constant_other_time_ms) { 223 _constant_other_time_ms_seq->add(constant_other_time_ms); 224 } 225 226 void G1Analytics::report_pending_cards(double pending_cards) { 227 _pending_cards_seq->add(pending_cards); 228 } 229 230 void G1Analytics::report_rs_length(double rs_length) { 231 _rs_length_seq->add(rs_length); 232 } 233 234 void G1Analytics::report_survivor_ratio(double ratio) { 235 _survivor_ratio->add(ratio); 236 } 237 238 double G1Analytics::predict_alloc_rate_ms() const { 239 return predict_zero_bounded(_alloc_rate_ms_seq); 240 } 241 242 double G1Analytics::predict_concurrent_refine_rate_ms() const { 243 return predict_zero_bounded(_concurrent_refine_rate_ms_seq); 244 } 245 246 double G1Analytics::predict_logged_cards_rate_ms() const { 247 return predict_zero_bounded(_logged_cards_rate_ms_seq); 248 } 249 250 double G1Analytics::predict_young_card_merge_to_scan_ratio() const { 251 return predict_in_unit_interval(_young_card_merge_to_scan_ratio_seq); 252 } 253 254 size_t G1Analytics::predict_scan_card_num(size_t rs_length, bool for_young_gc) const { 255 if (for_young_gc || !enough_samples_available(_mixed_card_merge_to_scan_ratio_seq)) { 256 return (size_t)(rs_length * predict_young_card_merge_to_scan_ratio()); 257 } else { 258 return (size_t)(rs_length * predict_in_unit_interval(_mixed_card_merge_to_scan_ratio_seq)); 259 } 260 } 261 262 double G1Analytics::predict_card_merge_time_ms(size_t card_num, bool for_young_gc) const { 263 if (for_young_gc || !enough_samples_available(_mixed_cost_per_card_merge_ms_seq)) { 264 return card_num * predict_zero_bounded(_young_cost_per_card_merge_ms_seq); 265 } else { 266 return card_num * predict_zero_bounded(_mixed_cost_per_card_merge_ms_seq); 267 } 268 } 269 270 double G1Analytics::predict_card_scan_time_ms(size_t card_num, bool for_young_gc) const { 271 if (for_young_gc || !enough_samples_available(_mixed_cost_per_card_scan_ms_seq)) { 272 return card_num * predict_zero_bounded(_young_cost_per_card_scan_ms_seq); 273 } else { 274 return card_num * predict_zero_bounded(_mixed_cost_per_card_scan_ms_seq); 275 } 276 } 277 278 double G1Analytics::predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const { 279 if (!enough_samples_available(_cost_per_byte_ms_during_cm_seq)) { 280 return (1.1 * bytes_to_copy) * predict_zero_bounded(_copy_cost_per_byte_ms_seq); 281 } else { 282 return bytes_to_copy * predict_zero_bounded(_cost_per_byte_ms_during_cm_seq); 283 } 284 } 285 286 double G1Analytics::predict_object_copy_time_ms(size_t bytes_to_copy, bool during_concurrent_mark) const { 287 if (during_concurrent_mark) { 288 return predict_object_copy_time_ms_during_cm(bytes_to_copy); 289 } else { 290 return bytes_to_copy * predict_zero_bounded(_copy_cost_per_byte_ms_seq); 291 } 292 } 293 294 double G1Analytics::predict_survivor_ratio() const { 295 return predict_in_unit_interval(_survivor_ratio); 296 } 297 298 double G1Analytics::predict_constant_other_time_ms() const { 299 return predict_zero_bounded(_constant_other_time_ms_seq); 300 } 301 302 double G1Analytics::predict_young_other_time_ms(size_t young_num) const { 303 return young_num * predict_zero_bounded(_young_other_cost_per_region_ms_seq); 304 } 305 306 double G1Analytics::predict_non_young_other_time_ms(size_t non_young_num) const { 307 return non_young_num * predict_zero_bounded(_non_young_other_cost_per_region_ms_seq); 308 } 309 310 double G1Analytics::predict_remark_time_ms() const { 311 return predict_zero_bounded(_concurrent_mark_remark_times_ms); 312 } 313 314 double G1Analytics::predict_cleanup_time_ms() const { 315 return predict_zero_bounded(_concurrent_mark_cleanup_times_ms); 316 } 317 318 size_t G1Analytics::predict_rs_length() const { 319 return predict_size(_rs_length_seq) + predict_size(_rs_length_diff_seq); 320 } 321 322 size_t G1Analytics::predict_pending_cards() const { 323 return predict_size(_pending_cards_seq); 324 } 325 326 double G1Analytics::last_known_gc_end_time_sec() const { 327 return _recent_prev_end_times_for_all_gcs_sec->oldest(); 328 } 329 330 void G1Analytics::update_recent_gc_times(double end_time_sec, 331 double pause_time_ms) { 332 _recent_gc_times_ms->add(pause_time_ms); 333 _recent_prev_end_times_for_all_gcs_sec->add(end_time_sec); 334 _prev_collection_pause_end_ms = end_time_sec * 1000.0; 335 } 336 337 void G1Analytics::report_concurrent_mark_cleanup_times_ms(double ms) { 338 _concurrent_mark_cleanup_times_ms->add(ms); 339 }