1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,384 @@
1.4 +/*
1.5 + * Copyright 2002-2007 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +// This class keeps statistical information and computes the
1.29 +// optimal free space for both the young and old generation
1.30 +// based on current application characteristics (based on gc cost
1.31 +// and application footprint).
1.32 +//
1.33 +// It also computes an optimal tenuring threshold between the young
1.34 +// and old generations, so as to equalize the cost of collections
1.35 +// of those generations, as well as optimial survivor space sizes
1.36 +// for the young generation.
1.37 +//
1.38 +// While this class is specifically intended for a generational system
1.39 +// consisting of a young gen (containing an Eden and two semi-spaces)
1.40 +// and a tenured gen, as well as a perm gen for reflective data, it
1.41 +// makes NO references to specific generations.
1.42 +//
1.43 +// 05/02/2003 Update
1.44 +// The 1.5 policy makes use of data gathered for the costs of GC on
1.45 +// specific generations. That data does reference specific
1.46 +// generation. Also diagnostics specific to generations have
1.47 +// been added.
1.48 +
1.49 +// Forward decls
1.50 +class elapsedTimer;
1.51 +
1.52 +class PSAdaptiveSizePolicy : public AdaptiveSizePolicy {
1.53 + friend class PSGCAdaptivePolicyCounters;
1.54 + private:
1.55 + // These values are used to record decisions made during the
1.56 + // policy. For example, if the young generation was decreased
1.57 + // to decrease the GC cost of minor collections the value
1.58 + // decrease_young_gen_for_throughput_true is used.
1.59 +
1.60 + // Last calculated sizes, in bytes, and aligned
1.61 + // NEEDS_CLEANUP should use sizes.hpp, but it works in ints, not size_t's
1.62 +
1.63 + // Time statistics
1.64 + AdaptivePaddedAverage* _avg_major_pause;
1.65 +
1.66 + // Footprint statistics
1.67 + AdaptiveWeightedAverage* _avg_base_footprint;
1.68 +
1.69 + // Statistical data gathered for GC
1.70 + GCStats _gc_stats;
1.71 +
1.72 + size_t _survivor_size_limit; // Limit in bytes of survivor size
1.73 + const double _collection_cost_margin_fraction;
1.74 +
1.75 + // Variable for estimating the major and minor pause times.
1.76 + // These variables represent linear least-squares fits of
1.77 + // the data.
1.78 + // major pause time vs. old gen size
1.79 + LinearLeastSquareFit* _major_pause_old_estimator;
1.80 + // major pause time vs. young gen size
1.81 + LinearLeastSquareFit* _major_pause_young_estimator;
1.82 +
1.83 +
1.84 + // These record the most recent collection times. They
1.85 + // are available as an alternative to using the averages
1.86 + // for making ergonomic decisions.
1.87 + double _latest_major_mutator_interval_seconds;
1.88 +
1.89 + const size_t _intra_generation_alignment; // alignment for eden, survivors
1.90 +
1.91 + const double _gc_minor_pause_goal_sec; // goal for maximum minor gc pause
1.92 +
1.93 + // The amount of live data in the heap at the last full GC, used
1.94 + // as a baseline to help us determine when we need to perform the
1.95 + // next full GC.
1.96 + size_t _live_at_last_full_gc;
1.97 +
1.98 + // decrease/increase the old generation for minor pause time
1.99 + int _change_old_gen_for_min_pauses;
1.100 +
1.101 + // increase/decrease the young generation for major pause time
1.102 + int _change_young_gen_for_maj_pauses;
1.103 +
1.104 +
1.105 + // Flag indicating that the adaptive policy is ready to use
1.106 + bool _old_gen_policy_is_ready;
1.107 +
1.108 + // Changing the generation sizing depends on the data that is
1.109 + // gathered about the effects of changes on the pause times and
1.110 + // throughput. These variable count the number of data points
1.111 + // gathered. The policy may use these counters as a threshhold
1.112 + // for reliable data.
1.113 + julong _young_gen_change_for_major_pause_count;
1.114 +
1.115 + // To facilitate faster growth at start up, supplement the normal
1.116 + // growth percentage for the young gen eden and the
1.117 + // old gen space for promotion with these value which decay
1.118 + // with increasing collections.
1.119 + uint _young_gen_size_increment_supplement;
1.120 + uint _old_gen_size_increment_supplement;
1.121 +
1.122 + // The number of bytes absorbed from eden into the old gen by moving the
1.123 + // boundary over live data.
1.124 + size_t _bytes_absorbed_from_eden;
1.125 +
1.126 + private:
1.127 +
1.128 + // Accessors
1.129 + AdaptivePaddedAverage* avg_major_pause() const { return _avg_major_pause; }
1.130 + double gc_minor_pause_goal_sec() const { return _gc_minor_pause_goal_sec; }
1.131 +
1.132 + // Change the young generation size to achieve a minor GC pause time goal
1.133 + void adjust_for_minor_pause_time(bool is_full_gc,
1.134 + size_t* desired_promo_size_ptr,
1.135 + size_t* desired_eden_size_ptr);
1.136 + // Change the generation sizes to achieve a GC pause time goal
1.137 + // Returned sizes are not necessarily aligned.
1.138 + void adjust_for_pause_time(bool is_full_gc,
1.139 + size_t* desired_promo_size_ptr,
1.140 + size_t* desired_eden_size_ptr);
1.141 + // Change the generation sizes to achieve an application throughput goal
1.142 + // Returned sizes are not necessarily aligned.
1.143 + void adjust_for_throughput(bool is_full_gc,
1.144 + size_t* desired_promo_size_ptr,
1.145 + size_t* desired_eden_size_ptr);
1.146 + // Change the generation sizes to achieve minimum footprint
1.147 + // Returned sizes are not aligned.
1.148 + size_t adjust_promo_for_footprint(size_t desired_promo_size,
1.149 + size_t desired_total);
1.150 + size_t adjust_eden_for_footprint(size_t desired_promo_size,
1.151 + size_t desired_total);
1.152 +
1.153 + // Size in bytes for an increment or decrement of eden.
1.154 + virtual size_t eden_increment(size_t cur_eden, uint percent_change);
1.155 + virtual size_t eden_decrement(size_t cur_eden);
1.156 + size_t eden_decrement_aligned_down(size_t cur_eden);
1.157 + size_t eden_increment_with_supplement_aligned_up(size_t cur_eden);
1.158 +
1.159 + // Size in bytes for an increment or decrement of the promotion area
1.160 + virtual size_t promo_increment(size_t cur_promo, uint percent_change);
1.161 + virtual size_t promo_decrement(size_t cur_promo);
1.162 + size_t promo_decrement_aligned_down(size_t cur_promo);
1.163 + size_t promo_increment_with_supplement_aligned_up(size_t cur_promo);
1.164 +
1.165 + // Decay the supplemental growth additive.
1.166 + void decay_supplemental_growth(bool is_full_gc);
1.167 +
1.168 + // Returns a change that has been scaled down. Result
1.169 + // is not aligned. (If useful, move to some shared
1.170 + // location.)
1.171 + size_t scale_down(size_t change, double part, double total);
1.172 +
1.173 + protected:
1.174 + // Time accessors
1.175 +
1.176 + // Footprint accessors
1.177 + size_t live_space() const {
1.178 + return (size_t)(avg_base_footprint()->average() +
1.179 + avg_young_live()->average() +
1.180 + avg_old_live()->average());
1.181 + }
1.182 + size_t free_space() const {
1.183 + return _eden_size + _promo_size;
1.184 + }
1.185 +
1.186 + void set_promo_size(size_t new_size) {
1.187 + _promo_size = new_size;
1.188 + }
1.189 + void set_survivor_size(size_t new_size) {
1.190 + _survivor_size = new_size;
1.191 + }
1.192 +
1.193 + // Update estimators
1.194 + void update_minor_pause_old_estimator(double minor_pause_in_ms);
1.195 +
1.196 + virtual GCPolicyKind kind() const { return _gc_ps_adaptive_size_policy; }
1.197 +
1.198 + public:
1.199 + // Use by ASPSYoungGen and ASPSOldGen to limit boundary moving.
1.200 + size_t eden_increment_aligned_up(size_t cur_eden);
1.201 + size_t eden_increment_aligned_down(size_t cur_eden);
1.202 + size_t promo_increment_aligned_up(size_t cur_promo);
1.203 + size_t promo_increment_aligned_down(size_t cur_promo);
1.204 +
1.205 + virtual size_t eden_increment(size_t cur_eden);
1.206 + virtual size_t promo_increment(size_t cur_promo);
1.207 +
1.208 + // Accessors for use by performance counters
1.209 + AdaptivePaddedNoZeroDevAverage* avg_promoted() const {
1.210 + return _gc_stats.avg_promoted();
1.211 + }
1.212 + AdaptiveWeightedAverage* avg_base_footprint() const {
1.213 + return _avg_base_footprint;
1.214 + }
1.215 +
1.216 + // Input arguments are initial free space sizes for young and old
1.217 + // generations, the initial survivor space size, the
1.218 + // alignment values and the pause & throughput goals.
1.219 + //
1.220 + // NEEDS_CLEANUP this is a singleton object
1.221 + PSAdaptiveSizePolicy(size_t init_eden_size,
1.222 + size_t init_promo_size,
1.223 + size_t init_survivor_size,
1.224 + size_t intra_generation_alignment,
1.225 + double gc_pause_goal_sec,
1.226 + double gc_minor_pause_goal_sec,
1.227 + uint gc_time_ratio);
1.228 +
1.229 + // Methods indicating events of interest to the adaptive size policy,
1.230 + // called by GC algorithms. It is the responsibility of users of this
1.231 + // policy to call these methods at the correct times!
1.232 + void major_collection_begin();
1.233 + void major_collection_end(size_t amount_live, GCCause::Cause gc_cause);
1.234 +
1.235 + //
1.236 + void tenured_allocation(size_t size) {
1.237 + _avg_pretenured->sample(size);
1.238 + }
1.239 +
1.240 + // Accessors
1.241 + // NEEDS_CLEANUP should use sizes.hpp
1.242 +
1.243 + size_t calculated_old_free_size_in_bytes() const {
1.244 + return (size_t)(_promo_size + avg_promoted()->padded_average());
1.245 + }
1.246 +
1.247 + size_t average_old_live_in_bytes() const {
1.248 + return (size_t) avg_old_live()->average();
1.249 + }
1.250 +
1.251 + size_t average_promoted_in_bytes() const {
1.252 + return (size_t)avg_promoted()->average();
1.253 + }
1.254 +
1.255 + size_t padded_average_promoted_in_bytes() const {
1.256 + return (size_t)avg_promoted()->padded_average();
1.257 + }
1.258 +
1.259 + int change_young_gen_for_maj_pauses() {
1.260 + return _change_young_gen_for_maj_pauses;
1.261 + }
1.262 + void set_change_young_gen_for_maj_pauses(int v) {
1.263 + _change_young_gen_for_maj_pauses = v;
1.264 + }
1.265 +
1.266 + int change_old_gen_for_min_pauses() {
1.267 + return _change_old_gen_for_min_pauses;
1.268 + }
1.269 + void set_change_old_gen_for_min_pauses(int v) {
1.270 + _change_old_gen_for_min_pauses = v;
1.271 + }
1.272 +
1.273 + // Return true if the old generation size was changed
1.274 + // to try to reach a pause time goal.
1.275 + bool old_gen_changed_for_pauses() {
1.276 + bool result = _change_old_gen_for_maj_pauses != 0 ||
1.277 + _change_old_gen_for_min_pauses != 0;
1.278 + return result;
1.279 + }
1.280 +
1.281 + // Return true if the young generation size was changed
1.282 + // to try to reach a pause time goal.
1.283 + bool young_gen_changed_for_pauses() {
1.284 + bool result = _change_young_gen_for_min_pauses != 0 ||
1.285 + _change_young_gen_for_maj_pauses != 0;
1.286 + return result;
1.287 + }
1.288 + // end flags for pause goal
1.289 +
1.290 + // Return true if the old generation size was changed
1.291 + // to try to reach a throughput goal.
1.292 + bool old_gen_changed_for_throughput() {
1.293 + bool result = _change_old_gen_for_throughput != 0;
1.294 + return result;
1.295 + }
1.296 +
1.297 + // Return true if the young generation size was changed
1.298 + // to try to reach a throughput goal.
1.299 + bool young_gen_changed_for_throughput() {
1.300 + bool result = _change_young_gen_for_throughput != 0;
1.301 + return result;
1.302 + }
1.303 +
1.304 + int decrease_for_footprint() { return _decrease_for_footprint; }
1.305 +
1.306 +
1.307 + // Accessors for estimators. The slope of the linear fit is
1.308 + // currently all that is used for making decisions.
1.309 +
1.310 + LinearLeastSquareFit* major_pause_old_estimator() {
1.311 + return _major_pause_old_estimator;
1.312 + }
1.313 +
1.314 + LinearLeastSquareFit* major_pause_young_estimator() {
1.315 + return _major_pause_young_estimator;
1.316 + }
1.317 +
1.318 +
1.319 + virtual void clear_generation_free_space_flags();
1.320 +
1.321 + float major_pause_old_slope() { return _major_pause_old_estimator->slope(); }
1.322 + float major_pause_young_slope() {
1.323 + return _major_pause_young_estimator->slope();
1.324 + }
1.325 + float major_collection_slope() { return _major_collection_estimator->slope();}
1.326 +
1.327 + bool old_gen_policy_is_ready() { return _old_gen_policy_is_ready; }
1.328 +
1.329 + // Given the amount of live data in the heap, should we
1.330 + // perform a Full GC?
1.331 + bool should_full_GC(size_t live_in_old_gen);
1.332 +
1.333 + // Calculates optimial free space sizes for both the old and young
1.334 + // generations. Stores results in _eden_size and _promo_size.
1.335 + // Takes current used space in all generations as input, as well
1.336 + // as an indication if a full gc has just been performed, for use
1.337 + // in deciding if an OOM error should be thrown.
1.338 + void compute_generation_free_space(size_t young_live,
1.339 + size_t eden_live,
1.340 + size_t old_live,
1.341 + size_t perm_live,
1.342 + size_t cur_eden, // current eden in bytes
1.343 + size_t max_old_gen_size,
1.344 + size_t max_eden_size,
1.345 + bool is_full_gc,
1.346 + GCCause::Cause gc_cause);
1.347 +
1.348 + // Calculates new survivor space size; returns a new tenuring threshold
1.349 + // value. Stores new survivor size in _survivor_size.
1.350 + int compute_survivor_space_size_and_threshold(bool is_survivor_overflow,
1.351 + int tenuring_threshold,
1.352 + size_t survivor_limit);
1.353 +
1.354 + // Return the maximum size of a survivor space if the young generation were of
1.355 + // size gen_size.
1.356 + size_t max_survivor_size(size_t gen_size) {
1.357 + // Never allow the target survivor size to grow more than MinSurvivorRatio
1.358 + // of the young generation size. We cannot grow into a two semi-space
1.359 + // system, with Eden zero sized. Even if the survivor space grows, from()
1.360 + // might grow by moving the bottom boundary "down" -- so from space will
1.361 + // remain almost full anyway (top() will be near end(), but there will be a
1.362 + // large filler object at the bottom).
1.363 + const size_t sz = gen_size / MinSurvivorRatio;
1.364 + const size_t alignment = _intra_generation_alignment;
1.365 + return sz > alignment ? align_size_down(sz, alignment) : alignment;
1.366 + }
1.367 +
1.368 + size_t live_at_last_full_gc() {
1.369 + return _live_at_last_full_gc;
1.370 + }
1.371 +
1.372 + size_t bytes_absorbed_from_eden() const { return _bytes_absorbed_from_eden; }
1.373 + void reset_bytes_absorbed_from_eden() { _bytes_absorbed_from_eden = 0; }
1.374 +
1.375 + void set_bytes_absorbed_from_eden(size_t val) {
1.376 + _bytes_absorbed_from_eden = val;
1.377 + }
1.378 +
1.379 + // Update averages that are always used (even
1.380 + // if adaptive sizing is turned off).
1.381 + void update_averages(bool is_survivor_overflow,
1.382 + size_t survived,
1.383 + size_t promoted);
1.384 +
1.385 + // Printing support
1.386 + virtual bool print_adaptive_size_policy_on(outputStream* st) const;
1.387 +};
