jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp@4dfb2df418f2 (annotated)

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp@4dfb2df418f2 (annotated)

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

Thu, 22 Sep 2011 10:57:37 -0700

author: johnc
date: Thu, 22 Sep 2011 10:57:37 -0700
changeset 3175: 4dfb2df418f2
parent 2314: f95d63e2154a
child 4037: da91efe96a93
permissions: -rw-r--r--

6484982: G1: process references during evacuation pauses
Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate.
Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp

 /*
  * 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
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 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSADAPTIVESIZEPOLICY_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSADAPTIVESIZEPOLICY_HPP
 #include "gc_implementation/shared/adaptiveSizePolicy.hpp"
 #include "gc_implementation/shared/gcStats.hpp"
 #include "gc_implementation/shared/gcUtil.hpp"
 #include "gc_interface/gcCause.hpp"
 // 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;
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSADAPTIVESIZEPOLICY_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp@4dfb2df418f2 (annotated)

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