jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp@c18cbe5936b8 (annotated)

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp@c18cbe5936b8 (annotated)

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp

Thu, 27 May 2010 19:08:38 -0700

author: trims
date: Thu, 27 May 2010 19:08:38 -0700
changeset 1907: c18cbe5936b8
parent 1822: 0bfd3fb24150
child 2314: f95d63e2154a
permissions: -rw-r--r--

6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

 /*
  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 // This class keeps statistical information and computes the
 // optimal free space for both the young and old generation
 // based on current application characteristics (based on gc cost
 // and application footprint).
 //
 // It also computes an optimal tenuring threshold between the young
 // and old generations, so as to equalize the cost of collections
 // of those generations, as well as optimial survivor space sizes
 // for the young generation.
 //
 // While this class is specifically intended for a generational system
 // consisting of a young gen (containing an Eden and two semi-spaces)
 // and a tenured gen, as well as a perm gen for reflective data, it
 // makes NO references to specific generations.
 //
 // 05/02/2003 Update
 // The 1.5 policy makes use of data gathered for the costs of GC on
 // specific generations.  That data does reference specific
 // generation.  Also diagnostics specific to generations have
 // been added.
 // Forward decls
 class elapsedTimer;
 class GenerationSizer;
 class PSAdaptiveSizePolicy : public AdaptiveSizePolicy {
  friend class PSGCAdaptivePolicyCounters;
  private:
   // These values are used to record decisions made during the
   // policy.  For example, if the young generation was decreased
   // to decrease the GC cost of minor collections the value
   // decrease_young_gen_for_throughput_true is used.
   // Last calculated sizes, in bytes, and aligned
   // NEEDS_CLEANUP should use sizes.hpp,  but it works in ints, not size_t's
   // Time statistics
   AdaptivePaddedAverage* _avg_major_pause;
   // Footprint statistics
   AdaptiveWeightedAverage* _avg_base_footprint;
   // Statistical data gathered for GC
   GCStats _gc_stats;
   size_t _survivor_size_limit;   // Limit in bytes of survivor size
   const double _collection_cost_margin_fraction;
   // Variable for estimating the major and minor pause times.
   // These variables represent linear least-squares fits of
   // the data.
   //   major pause time vs. old gen size
   LinearLeastSquareFit* _major_pause_old_estimator;
   //   major pause time vs. young gen size
   LinearLeastSquareFit* _major_pause_young_estimator;
   // These record the most recent collection times.  They
   // are available as an alternative to using the averages
   // for making ergonomic decisions.
   double _latest_major_mutator_interval_seconds;
   const size_t _intra_generation_alignment; // alignment for eden, survivors
   const double _gc_minor_pause_goal_sec;    // goal for maximum minor gc pause
   // The amount of live data in the heap at the last full GC, used
   // as a baseline to help us determine when we need to perform the
   // next full GC.
   size_t _live_at_last_full_gc;
   // decrease/increase the old generation for minor pause time
   int _change_old_gen_for_min_pauses;
   // increase/decrease the young generation for major pause time
   int _change_young_gen_for_maj_pauses;
   // Flag indicating that the adaptive policy is ready to use
   bool _old_gen_policy_is_ready;
   // Changing the generation sizing depends on the data that is
   // gathered about the effects of changes on the pause times and
   // throughput.  These variable count the number of data points
   // gathered.  The policy may use these counters as a threshhold
   // for reliable data.
   julong _young_gen_change_for_major_pause_count;
   // To facilitate faster growth at start up, supplement the normal
   // growth percentage for the young gen eden and the
   // old gen space for promotion with these value which decay
   // with increasing collections.
   uint _young_gen_size_increment_supplement;
   uint _old_gen_size_increment_supplement;
   // The number of bytes absorbed from eden into the old gen by moving the
   // boundary over live data.
   size_t _bytes_absorbed_from_eden;
  private:
   // Accessors
   AdaptivePaddedAverage* avg_major_pause() const { return _avg_major_pause; }
   double gc_minor_pause_goal_sec() const { return _gc_minor_pause_goal_sec; }
   // Change the young generation size to achieve a minor GC pause time goal
   void adjust_for_minor_pause_time(bool is_full_gc,
                                    size_t* desired_promo_size_ptr,
                                    size_t* desired_eden_size_ptr);
   // Change the generation sizes to achieve a GC pause time goal
   // Returned sizes are not necessarily aligned.
   void adjust_for_pause_time(bool is_full_gc,
                          size_t* desired_promo_size_ptr,
                          size_t* desired_eden_size_ptr);
   // Change the generation sizes to achieve an application throughput goal
   // Returned sizes are not necessarily aligned.
   void adjust_for_throughput(bool is_full_gc,
                              size_t* desired_promo_size_ptr,
                              size_t* desired_eden_size_ptr);
   // Change the generation sizes to achieve minimum footprint
   // Returned sizes are not aligned.
   size_t adjust_promo_for_footprint(size_t desired_promo_size,
                                     size_t desired_total);
   size_t adjust_eden_for_footprint(size_t desired_promo_size,
                                    size_t desired_total);
   // Size in bytes for an increment or decrement of eden.
   virtual size_t eden_increment(size_t cur_eden, uint percent_change);
   virtual size_t eden_decrement(size_t cur_eden);
   size_t eden_decrement_aligned_down(size_t cur_eden);
   size_t eden_increment_with_supplement_aligned_up(size_t cur_eden);
   // Size in bytes for an increment or decrement of the promotion area
   virtual size_t promo_increment(size_t cur_promo, uint percent_change);
   virtual size_t promo_decrement(size_t cur_promo);
   size_t promo_decrement_aligned_down(size_t cur_promo);
   size_t promo_increment_with_supplement_aligned_up(size_t cur_promo);
   // Decay the supplemental growth additive.
   void decay_supplemental_growth(bool is_full_gc);
   // Returns a change that has been scaled down.  Result
   // is not aligned.  (If useful, move to some shared
   // location.)
   size_t scale_down(size_t change, double part, double total);
  protected:
   // Time accessors
   // Footprint accessors
   size_t live_space() const {
     return (size_t)(avg_base_footprint()->average() +
                     avg_young_live()->average() +
                     avg_old_live()->average());
   }
   size_t free_space() const {
     return _eden_size + _promo_size;
   }
   void set_promo_size(size_t new_size) {
     _promo_size = new_size;
   }
   void set_survivor_size(size_t new_size) {
     _survivor_size = new_size;
   }
   // Update estimators
   void update_minor_pause_old_estimator(double minor_pause_in_ms);
   virtual GCPolicyKind kind() const { return _gc_ps_adaptive_size_policy; }
  public:
   // Use by ASPSYoungGen and ASPSOldGen to limit boundary moving.
   size_t eden_increment_aligned_up(size_t cur_eden);
   size_t eden_increment_aligned_down(size_t cur_eden);
   size_t promo_increment_aligned_up(size_t cur_promo);
   size_t promo_increment_aligned_down(size_t cur_promo);
   virtual size_t eden_increment(size_t cur_eden);
   virtual size_t promo_increment(size_t cur_promo);
   // Accessors for use by performance counters
   AdaptivePaddedNoZeroDevAverage*  avg_promoted() const {
     return _gc_stats.avg_promoted();
   }
   AdaptiveWeightedAverage* avg_base_footprint() const {
     return _avg_base_footprint;
   }
   // Input arguments are initial free space sizes for young and old
   // generations, the initial survivor space size, the
   // alignment values and the pause & throughput goals.
   //
   // NEEDS_CLEANUP this is a singleton object
   PSAdaptiveSizePolicy(size_t init_eden_size,
                        size_t init_promo_size,
                        size_t init_survivor_size,
                        size_t intra_generation_alignment,
                        double gc_pause_goal_sec,
                        double gc_minor_pause_goal_sec,
                        uint gc_time_ratio);
   // Methods indicating events of interest to the adaptive size policy,
   // called by GC algorithms. It is the responsibility of users of this
   // policy to call these methods at the correct times!
   void major_collection_begin();
   void major_collection_end(size_t amount_live, GCCause::Cause gc_cause);
   //
   void tenured_allocation(size_t size) {
     _avg_pretenured->sample(size);
   }
   // Accessors
   // NEEDS_CLEANUP   should use sizes.hpp
   size_t calculated_old_free_size_in_bytes() const {
     return (size_t)(_promo_size + avg_promoted()->padded_average());
   }
   size_t average_old_live_in_bytes() const {
     return (size_t) avg_old_live()->average();
   }
   size_t average_promoted_in_bytes() const {
     return (size_t)avg_promoted()->average();
   }
   size_t padded_average_promoted_in_bytes() const {
     return (size_t)avg_promoted()->padded_average();
   }
   int change_young_gen_for_maj_pauses() {
     return _change_young_gen_for_maj_pauses;
   }
   void set_change_young_gen_for_maj_pauses(int v) {
     _change_young_gen_for_maj_pauses = v;
   }
   int change_old_gen_for_min_pauses() {
     return _change_old_gen_for_min_pauses;
   }
   void set_change_old_gen_for_min_pauses(int v) {
     _change_old_gen_for_min_pauses = v;
   }
   // Return true if the old generation size was changed
   // to try to reach a pause time goal.
   bool old_gen_changed_for_pauses() {
     bool result = _change_old_gen_for_maj_pauses != 0 ||
                   _change_old_gen_for_min_pauses != 0;
     return result;
   }
   // Return true if the young generation size was changed
   // to try to reach a pause time goal.
   bool young_gen_changed_for_pauses() {
     bool result = _change_young_gen_for_min_pauses != 0 ||
                   _change_young_gen_for_maj_pauses != 0;
     return result;
   }
   // end flags for pause goal
   // Return true if the old generation size was changed
   // to try to reach a throughput goal.
   bool old_gen_changed_for_throughput() {
     bool result = _change_old_gen_for_throughput != 0;
     return result;
   }
   // Return true if the young generation size was changed
   // to try to reach a throughput goal.
   bool young_gen_changed_for_throughput() {
     bool result = _change_young_gen_for_throughput != 0;
     return result;
   }
   int decrease_for_footprint() { return _decrease_for_footprint; }
   // Accessors for estimators.  The slope of the linear fit is
   // currently all that is used for making decisions.
   LinearLeastSquareFit* major_pause_old_estimator() {
     return _major_pause_old_estimator;
   }
   LinearLeastSquareFit* major_pause_young_estimator() {
     return _major_pause_young_estimator;
   }
   virtual void clear_generation_free_space_flags();
   float major_pause_old_slope() { return _major_pause_old_estimator->slope(); }
   float major_pause_young_slope() {
     return _major_pause_young_estimator->slope();
   }
   float major_collection_slope() { return _major_collection_estimator->slope();}
   bool old_gen_policy_is_ready() { return _old_gen_policy_is_ready; }
   // Given the amount of live data in the heap, should we
   // perform a Full GC?
   bool should_full_GC(size_t live_in_old_gen);
   // Calculates optimial free space sizes for both the old and young
   // generations.  Stores results in _eden_size and _promo_size.
   // Takes current used space in all generations as input, as well
   // as an indication if a full gc has just been performed, for use
   // in deciding if an OOM error should be thrown.
   void compute_generation_free_space(size_t young_live,
                                      size_t eden_live,
                                      size_t old_live,
                                      size_t perm_live,
                                      size_t cur_eden,  // current eden in bytes
                                      size_t max_old_gen_size,
                                      size_t max_eden_size,
                                      bool   is_full_gc,
                                      GCCause::Cause gc_cause,
                                      CollectorPolicy* collector_policy);
   // Calculates new survivor space size;  returns a new tenuring threshold
   // value. Stores new survivor size in _survivor_size.
   int compute_survivor_space_size_and_threshold(bool   is_survivor_overflow,
                                                 int    tenuring_threshold,
                                                 size_t survivor_limit);
   // Return the maximum size of a survivor space if the young generation were of
   // size gen_size.
   size_t max_survivor_size(size_t gen_size) {
     // Never allow the target survivor size to grow more than MinSurvivorRatio
     // of the young generation size.  We cannot grow into a two semi-space
     // system, with Eden zero sized.  Even if the survivor space grows, from()
     // might grow by moving the bottom boundary "down" -- so from space will
     // remain almost full anyway (top() will be near end(), but there will be a
     // large filler object at the bottom).
     const size_t sz = gen_size / MinSurvivorRatio;
     const size_t alignment = _intra_generation_alignment;
     return sz > alignment ? align_size_down(sz, alignment) : alignment;
   }
   size_t live_at_last_full_gc() {
     return _live_at_last_full_gc;
   }
   size_t bytes_absorbed_from_eden() const { return _bytes_absorbed_from_eden; }
   void   reset_bytes_absorbed_from_eden() { _bytes_absorbed_from_eden = 0; }
   void set_bytes_absorbed_from_eden(size_t val) {
     _bytes_absorbed_from_eden = val;
   }
   // Update averages that are always used (even
   // if adaptive sizing is turned off).
   void update_averages(bool is_survivor_overflow,
                        size_t survived,
                        size_t promoted);
   // Printing support
   virtual bool print_adaptive_size_policy_on(outputStream* st) const;
 };

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp@c18cbe5936b8 (annotated)

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp