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annotate src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp @ 6725:da91efe96a93
6964458: Reimplement class meta-data storage to use native memory
Summary: Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes
Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland
Contributed-by: jmasa <jon.masamitsu@oracle.com>, stefank <stefan.karlsson@oracle.com>, mgerdin <mikael.gerdin@oracle.com>, never <tom.rodriguez@oracle.com>
| author | coleenp |
|---|---|
| date | Sat, 01 Sep 2012 13:25:18 -0400 |
| parents | f95d63e2154a |
| children | 22b8d3d181d9 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSADAPTIVESIZEPOLICY_HPP |
| 26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSADAPTIVESIZEPOLICY_HPP | |
| 27 | |
| 28 #include "gc_implementation/shared/adaptiveSizePolicy.hpp" | |
| 29 #include "gc_implementation/shared/gcStats.hpp" | |
| 30 #include "gc_implementation/shared/gcUtil.hpp" | |
| 31 #include "gc_interface/gcCause.hpp" | |
| 32 | |
| 0 | 33 // This class keeps statistical information and computes the |
| 34 // optimal free space for both the young and old generation | |
| 35 // based on current application characteristics (based on gc cost | |
| 36 // and application footprint). | |
| 37 // | |
| 38 // It also computes an optimal tenuring threshold between the young | |
| 39 // and old generations, so as to equalize the cost of collections | |
| 40 // of those generations, as well as optimial survivor space sizes | |
| 41 // for the young generation. | |
| 42 // | |
| 43 // While this class is specifically intended for a generational system | |
| 44 // consisting of a young gen (containing an Eden and two semi-spaces) | |
| 45 // and a tenured gen, as well as a perm gen for reflective data, it | |
| 46 // makes NO references to specific generations. | |
| 47 // | |
| 48 // 05/02/2003 Update | |
| 49 // The 1.5 policy makes use of data gathered for the costs of GC on | |
| 50 // specific generations. That data does reference specific | |
| 51 // generation. Also diagnostics specific to generations have | |
| 52 // been added. | |
| 53 | |
| 54 // Forward decls | |
| 55 class elapsedTimer; | |
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56 class GenerationSizer; |
| 0 | 57 |
| 58 class PSAdaptiveSizePolicy : public AdaptiveSizePolicy { | |
| 59 friend class PSGCAdaptivePolicyCounters; | |
| 60 private: | |
| 61 // These values are used to record decisions made during the | |
| 62 // policy. For example, if the young generation was decreased | |
| 63 // to decrease the GC cost of minor collections the value | |
| 64 // decrease_young_gen_for_throughput_true is used. | |
| 65 | |
| 66 // Last calculated sizes, in bytes, and aligned | |
| 67 // NEEDS_CLEANUP should use sizes.hpp, but it works in ints, not size_t's | |
| 68 | |
| 69 // Time statistics | |
| 70 AdaptivePaddedAverage* _avg_major_pause; | |
| 71 | |
| 72 // Footprint statistics | |
| 73 AdaptiveWeightedAverage* _avg_base_footprint; | |
| 74 | |
| 75 // Statistical data gathered for GC | |
| 76 GCStats _gc_stats; | |
| 77 | |
| 78 size_t _survivor_size_limit; // Limit in bytes of survivor size | |
| 79 const double _collection_cost_margin_fraction; | |
| 80 | |
| 81 // Variable for estimating the major and minor pause times. | |
| 82 // These variables represent linear least-squares fits of | |
| 83 // the data. | |
| 84 // major pause time vs. old gen size | |
| 85 LinearLeastSquareFit* _major_pause_old_estimator; | |
| 86 // major pause time vs. young gen size | |
| 87 LinearLeastSquareFit* _major_pause_young_estimator; | |
| 88 | |
| 89 | |
| 90 // These record the most recent collection times. They | |
| 91 // are available as an alternative to using the averages | |
| 92 // for making ergonomic decisions. | |
| 93 double _latest_major_mutator_interval_seconds; | |
| 94 | |
| 95 const size_t _intra_generation_alignment; // alignment for eden, survivors | |
| 96 | |
| 97 const double _gc_minor_pause_goal_sec; // goal for maximum minor gc pause | |
| 98 | |
| 99 // The amount of live data in the heap at the last full GC, used | |
| 100 // as a baseline to help us determine when we need to perform the | |
| 101 // next full GC. | |
| 102 size_t _live_at_last_full_gc; | |
| 103 | |
| 104 // decrease/increase the old generation for minor pause time | |
| 105 int _change_old_gen_for_min_pauses; | |
| 106 | |
| 107 // increase/decrease the young generation for major pause time | |
| 108 int _change_young_gen_for_maj_pauses; | |
| 109 | |
| 110 | |
| 111 // Flag indicating that the adaptive policy is ready to use | |
| 112 bool _old_gen_policy_is_ready; | |
| 113 | |
| 114 // Changing the generation sizing depends on the data that is | |
| 115 // gathered about the effects of changes on the pause times and | |
| 116 // throughput. These variable count the number of data points | |
| 117 // gathered. The policy may use these counters as a threshhold | |
| 118 // for reliable data. | |
| 119 julong _young_gen_change_for_major_pause_count; | |
| 120 | |
| 121 // To facilitate faster growth at start up, supplement the normal | |
| 122 // growth percentage for the young gen eden and the | |
| 123 // old gen space for promotion with these value which decay | |
| 124 // with increasing collections. | |
| 125 uint _young_gen_size_increment_supplement; | |
| 126 uint _old_gen_size_increment_supplement; | |
| 127 | |
| 128 // The number of bytes absorbed from eden into the old gen by moving the | |
| 129 // boundary over live data. | |
| 130 size_t _bytes_absorbed_from_eden; | |
| 131 | |
| 132 private: | |
| 133 | |
| 134 // Accessors | |
| 135 AdaptivePaddedAverage* avg_major_pause() const { return _avg_major_pause; } | |
| 136 double gc_minor_pause_goal_sec() const { return _gc_minor_pause_goal_sec; } | |
| 137 | |
| 138 // Change the young generation size to achieve a minor GC pause time goal | |
| 139 void adjust_for_minor_pause_time(bool is_full_gc, | |
| 140 size_t* desired_promo_size_ptr, | |
| 141 size_t* desired_eden_size_ptr); | |
| 142 // Change the generation sizes to achieve a GC pause time goal | |
| 143 // Returned sizes are not necessarily aligned. | |
| 144 void adjust_for_pause_time(bool is_full_gc, | |
| 145 size_t* desired_promo_size_ptr, | |
| 146 size_t* desired_eden_size_ptr); | |
| 147 // Change the generation sizes to achieve an application throughput goal | |
| 148 // Returned sizes are not necessarily aligned. | |
| 149 void adjust_for_throughput(bool is_full_gc, | |
| 150 size_t* desired_promo_size_ptr, | |
| 151 size_t* desired_eden_size_ptr); | |
| 152 // Change the generation sizes to achieve minimum footprint | |
| 153 // Returned sizes are not aligned. | |
| 154 size_t adjust_promo_for_footprint(size_t desired_promo_size, | |
| 155 size_t desired_total); | |
| 156 size_t adjust_eden_for_footprint(size_t desired_promo_size, | |
| 157 size_t desired_total); | |
| 158 | |
| 159 // Size in bytes for an increment or decrement of eden. | |
| 160 virtual size_t eden_increment(size_t cur_eden, uint percent_change); | |
| 161 virtual size_t eden_decrement(size_t cur_eden); | |
| 162 size_t eden_decrement_aligned_down(size_t cur_eden); | |
| 163 size_t eden_increment_with_supplement_aligned_up(size_t cur_eden); | |
| 164 | |
| 165 // Size in bytes for an increment or decrement of the promotion area | |
| 166 virtual size_t promo_increment(size_t cur_promo, uint percent_change); | |
| 167 virtual size_t promo_decrement(size_t cur_promo); | |
| 168 size_t promo_decrement_aligned_down(size_t cur_promo); | |
| 169 size_t promo_increment_with_supplement_aligned_up(size_t cur_promo); | |
| 170 | |
| 171 // Decay the supplemental growth additive. | |
| 172 void decay_supplemental_growth(bool is_full_gc); | |
| 173 | |
| 174 // Returns a change that has been scaled down. Result | |
| 175 // is not aligned. (If useful, move to some shared | |
| 176 // location.) | |
| 177 size_t scale_down(size_t change, double part, double total); | |
| 178 | |
| 179 protected: | |
| 180 // Time accessors | |
| 181 | |
| 182 // Footprint accessors | |
| 183 size_t live_space() const { | |
| 184 return (size_t)(avg_base_footprint()->average() + | |
| 185 avg_young_live()->average() + | |
| 186 avg_old_live()->average()); | |
| 187 } | |
| 188 size_t free_space() const { | |
| 189 return _eden_size + _promo_size; | |
| 190 } | |
| 191 | |
| 192 void set_promo_size(size_t new_size) { | |
| 193 _promo_size = new_size; | |
| 194 } | |
| 195 void set_survivor_size(size_t new_size) { | |
| 196 _survivor_size = new_size; | |
| 197 } | |
| 198 | |
| 199 // Update estimators | |
| 200 void update_minor_pause_old_estimator(double minor_pause_in_ms); | |
| 201 | |
| 202 virtual GCPolicyKind kind() const { return _gc_ps_adaptive_size_policy; } | |
| 203 | |
| 204 public: | |
| 205 // Use by ASPSYoungGen and ASPSOldGen to limit boundary moving. | |
| 206 size_t eden_increment_aligned_up(size_t cur_eden); | |
| 207 size_t eden_increment_aligned_down(size_t cur_eden); | |
| 208 size_t promo_increment_aligned_up(size_t cur_promo); | |
| 209 size_t promo_increment_aligned_down(size_t cur_promo); | |
| 210 | |
| 211 virtual size_t eden_increment(size_t cur_eden); | |
| 212 virtual size_t promo_increment(size_t cur_promo); | |
| 213 | |
| 214 // Accessors for use by performance counters | |
| 215 AdaptivePaddedNoZeroDevAverage* avg_promoted() const { | |
| 216 return _gc_stats.avg_promoted(); | |
| 217 } | |
| 218 AdaptiveWeightedAverage* avg_base_footprint() const { | |
| 219 return _avg_base_footprint; | |
| 220 } | |
| 221 | |
| 222 // Input arguments are initial free space sizes for young and old | |
| 223 // generations, the initial survivor space size, the | |
| 224 // alignment values and the pause & throughput goals. | |
| 225 // | |
| 226 // NEEDS_CLEANUP this is a singleton object | |
| 227 PSAdaptiveSizePolicy(size_t init_eden_size, | |
| 228 size_t init_promo_size, | |
| 229 size_t init_survivor_size, | |
| 230 size_t intra_generation_alignment, | |
| 231 double gc_pause_goal_sec, | |
| 232 double gc_minor_pause_goal_sec, | |
| 233 uint gc_time_ratio); | |
| 234 | |
| 235 // Methods indicating events of interest to the adaptive size policy, | |
| 236 // called by GC algorithms. It is the responsibility of users of this | |
| 237 // policy to call these methods at the correct times! | |
| 238 void major_collection_begin(); | |
| 239 void major_collection_end(size_t amount_live, GCCause::Cause gc_cause); | |
| 240 | |
| 241 // | |
| 242 void tenured_allocation(size_t size) { | |
| 243 _avg_pretenured->sample(size); | |
| 244 } | |
| 245 | |
| 246 // Accessors | |
| 247 // NEEDS_CLEANUP should use sizes.hpp | |
| 248 | |
| 249 size_t calculated_old_free_size_in_bytes() const { | |
| 250 return (size_t)(_promo_size + avg_promoted()->padded_average()); | |
| 251 } | |
| 252 | |
| 253 size_t average_old_live_in_bytes() const { | |
| 254 return (size_t) avg_old_live()->average(); | |
| 255 } | |
| 256 | |
| 257 size_t average_promoted_in_bytes() const { | |
| 258 return (size_t)avg_promoted()->average(); | |
| 259 } | |
| 260 | |
| 261 size_t padded_average_promoted_in_bytes() const { | |
| 262 return (size_t)avg_promoted()->padded_average(); | |
| 263 } | |
| 264 | |
| 265 int change_young_gen_for_maj_pauses() { | |
| 266 return _change_young_gen_for_maj_pauses; | |
| 267 } | |
| 268 void set_change_young_gen_for_maj_pauses(int v) { | |
| 269 _change_young_gen_for_maj_pauses = v; | |
| 270 } | |
| 271 | |
| 272 int change_old_gen_for_min_pauses() { | |
| 273 return _change_old_gen_for_min_pauses; | |
| 274 } | |
| 275 void set_change_old_gen_for_min_pauses(int v) { | |
| 276 _change_old_gen_for_min_pauses = v; | |
| 277 } | |
| 278 | |
| 279 // Return true if the old generation size was changed | |
| 280 // to try to reach a pause time goal. | |
| 281 bool old_gen_changed_for_pauses() { | |
| 282 bool result = _change_old_gen_for_maj_pauses != 0 || | |
| 283 _change_old_gen_for_min_pauses != 0; | |
| 284 return result; | |
| 285 } | |
| 286 | |
| 287 // Return true if the young generation size was changed | |
| 288 // to try to reach a pause time goal. | |
| 289 bool young_gen_changed_for_pauses() { | |
| 290 bool result = _change_young_gen_for_min_pauses != 0 || | |
| 291 _change_young_gen_for_maj_pauses != 0; | |
| 292 return result; | |
| 293 } | |
| 294 // end flags for pause goal | |
| 295 | |
| 296 // Return true if the old generation size was changed | |
| 297 // to try to reach a throughput goal. | |
| 298 bool old_gen_changed_for_throughput() { | |
| 299 bool result = _change_old_gen_for_throughput != 0; | |
| 300 return result; | |
| 301 } | |
| 302 | |
| 303 // Return true if the young generation size was changed | |
| 304 // to try to reach a throughput goal. | |
| 305 bool young_gen_changed_for_throughput() { | |
| 306 bool result = _change_young_gen_for_throughput != 0; | |
| 307 return result; | |
| 308 } | |
| 309 | |
| 310 int decrease_for_footprint() { return _decrease_for_footprint; } | |
| 311 | |
| 312 | |
| 313 // Accessors for estimators. The slope of the linear fit is | |
| 314 // currently all that is used for making decisions. | |
| 315 | |
| 316 LinearLeastSquareFit* major_pause_old_estimator() { | |
| 317 return _major_pause_old_estimator; | |
| 318 } | |
| 319 | |
| 320 LinearLeastSquareFit* major_pause_young_estimator() { | |
| 321 return _major_pause_young_estimator; | |
| 322 } | |
| 323 | |
| 324 | |
| 325 virtual void clear_generation_free_space_flags(); | |
| 326 | |
| 327 float major_pause_old_slope() { return _major_pause_old_estimator->slope(); } | |
| 328 float major_pause_young_slope() { | |
| 329 return _major_pause_young_estimator->slope(); | |
| 330 } | |
| 331 float major_collection_slope() { return _major_collection_estimator->slope();} | |
| 332 | |
| 333 bool old_gen_policy_is_ready() { return _old_gen_policy_is_ready; } | |
| 334 | |
| 335 // Given the amount of live data in the heap, should we | |
| 336 // perform a Full GC? | |
| 337 bool should_full_GC(size_t live_in_old_gen); | |
| 338 | |
| 339 // Calculates optimial free space sizes for both the old and young | |
| 340 // generations. Stores results in _eden_size and _promo_size. | |
| 341 // Takes current used space in all generations as input, as well | |
| 342 // as an indication if a full gc has just been performed, for use | |
| 343 // in deciding if an OOM error should be thrown. | |
| 344 void compute_generation_free_space(size_t young_live, | |
| 345 size_t eden_live, | |
| 346 size_t old_live, | |
| 347 size_t cur_eden, // current eden in bytes | |
| 348 size_t max_old_gen_size, | |
| 349 size_t max_eden_size, | |
| 350 bool is_full_gc, | |
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351 GCCause::Cause gc_cause, |
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352 CollectorPolicy* collector_policy); |
| 0 | 353 |
| 354 // Calculates new survivor space size; returns a new tenuring threshold | |
| 355 // value. Stores new survivor size in _survivor_size. | |
| 356 int compute_survivor_space_size_and_threshold(bool is_survivor_overflow, | |
| 357 int tenuring_threshold, | |
| 358 size_t survivor_limit); | |
| 359 | |
| 360 // Return the maximum size of a survivor space if the young generation were of | |
| 361 // size gen_size. | |
| 362 size_t max_survivor_size(size_t gen_size) { | |
| 363 // Never allow the target survivor size to grow more than MinSurvivorRatio | |
| 364 // of the young generation size. We cannot grow into a two semi-space | |
| 365 // system, with Eden zero sized. Even if the survivor space grows, from() | |
| 366 // might grow by moving the bottom boundary "down" -- so from space will | |
| 367 // remain almost full anyway (top() will be near end(), but there will be a | |
| 368 // large filler object at the bottom). | |
| 369 const size_t sz = gen_size / MinSurvivorRatio; | |
| 370 const size_t alignment = _intra_generation_alignment; | |
| 371 return sz > alignment ? align_size_down(sz, alignment) : alignment; | |
| 372 } | |
| 373 | |
| 374 size_t live_at_last_full_gc() { | |
| 375 return _live_at_last_full_gc; | |
| 376 } | |
| 377 | |
| 378 size_t bytes_absorbed_from_eden() const { return _bytes_absorbed_from_eden; } | |
| 379 void reset_bytes_absorbed_from_eden() { _bytes_absorbed_from_eden = 0; } | |
| 380 | |
| 381 void set_bytes_absorbed_from_eden(size_t val) { | |
| 382 _bytes_absorbed_from_eden = val; | |
| 383 } | |
| 384 | |
| 385 // Update averages that are always used (even | |
| 386 // if adaptive sizing is turned off). | |
| 387 void update_averages(bool is_survivor_overflow, | |
| 388 size_t survived, | |
| 389 size_t promoted); | |
| 390 | |
| 391 // Printing support | |
| 392 virtual bool print_adaptive_size_policy_on(outputStream* st) const; | |
| 393 }; | |
| 1972 | 394 |
| 395 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSADAPTIVESIZEPOLICY_HPP |