Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright 2004-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  *

  */

 // This class keeps statistical information and computes the

 // size of the heap for the concurrent mark sweep collector.

 //

 // Cost for garbage collector include cost for

 //   minor collection

 //   concurrent collection

 //      stop-the-world component

 //      concurrent component

 //   major compacting collection

 //      uses decaying cost

 // Forward decls

 class elapsedTimer;

 class CMSAdaptiveSizePolicy : public AdaptiveSizePolicy {

  friend class CMSGCAdaptivePolicyCounters;

  friend class CMSCollector;

  private:

   // Total number of processors available

   int _processor_count;

   // Number of processors used by the concurrent phases of GC

   // This number is assumed to be the same for all concurrent

   // phases.

   int _concurrent_processor_count;

   // Time that the mutators run exclusive of a particular

   // phase.  For example, the time the mutators run excluding

   // the time during which the cms collector runs concurrently

   // with the mutators.

   //   Between end of most recent cms reset and start of initial mark

                 // This may be redundant

   double _latest_cms_reset_end_to_initial_mark_start_secs;

   //   Between end of the most recent initial mark and start of remark

   double _latest_cms_initial_mark_end_to_remark_start_secs;

   //   Between end of most recent collection and start of

   //   a concurrent collection

   double _latest_cms_collection_end_to_collection_start_secs;

   //   Times of the concurrent phases of the most recent

   //   concurrent collection

   double _latest_cms_concurrent_marking_time_secs;

   double _latest_cms_concurrent_precleaning_time_secs;

   double _latest_cms_concurrent_sweeping_time_secs;

   //   Between end of most recent STW MSC and start of next STW MSC

   double _latest_cms_msc_end_to_msc_start_time_secs;

   //   Between end of most recent MS and start of next MS

   //   This does not include any time spent during a concurrent

   // collection.

   double _latest_cms_ms_end_to_ms_start;

   //   Between start and end of the initial mark of the most recent

   // concurrent collection.

   double _latest_cms_initial_mark_start_to_end_time_secs;

   //   Between start and end of the remark phase of the most recent

   // concurrent collection

   double _latest_cms_remark_start_to_end_time_secs;

   //   Between start and end of the most recent MS STW marking phase

   double _latest_cms_ms_marking_start_to_end_time_secs;

   // Pause time timers

   static elapsedTimer _STW_timer;

   // Concurrent collection timer.  Used for total of all concurrent phases

   // during 1 collection cycle.

   static elapsedTimer _concurrent_timer;

   // When the size of the generation is changed, the size

   // of the change will rounded up or down (depending on the

   // type of change) by this value.

   size_t _generation_alignment;

   // If this variable is true, the size of the young generation

   // may be changed in order to reduce the pause(s) of the

   // collection of the tenured generation in order to meet the

   // pause time goal.  It is common to change the size of the

   // tenured generation in order to meet the pause time goal

   // for the tenured generation.  With the CMS collector for

   // the tenured generation, the size of the young generation

   // can have an significant affect on the pause times for collecting the

   // tenured generation.

   // This is a duplicate of a variable in PSAdaptiveSizePolicy.  It

   // is duplicated because it is not clear that it is general enough

   // to go into AdaptiveSizePolicy.

   int _change_young_gen_for_maj_pauses;

   // Variable that is set to true after a collection.

   bool _first_after_collection;

   // Fraction of collections that are of each type

   double concurrent_fraction() const;

   double STW_msc_fraction() const;

   double STW_ms_fraction() const;

   // This call cannot be put into the epilogue as long as some

   // of the counters can be set during concurrent phases.

   virtual void clear_generation_free_space_flags();

   void set_first_after_collection() { _first_after_collection = true; }

  protected:

   // Average of the sum of the concurrent times for

   // one collection in seconds.

   AdaptiveWeightedAverage* _avg_concurrent_time;

   // Average time between concurrent collections in seconds.

   AdaptiveWeightedAverage* _avg_concurrent_interval;

   // Average cost of the concurrent part of a collection

   // in seconds.

   AdaptiveWeightedAverage* _avg_concurrent_gc_cost;

   // Average of the initial pause of a concurrent collection in seconds.

   AdaptivePaddedAverage* _avg_initial_pause;

   // Average of the remark pause of a concurrent collection in seconds.

   AdaptivePaddedAverage* _avg_remark_pause;

   // Average of the stop-the-world (STW) (initial mark + remark)

   // times in seconds for concurrent collections.

   AdaptiveWeightedAverage* _avg_cms_STW_time;

   // Average of the STW collection cost for concurrent collections.

   AdaptiveWeightedAverage* _avg_cms_STW_gc_cost;

   // Average of the bytes free at the start of the sweep.

   AdaptiveWeightedAverage* _avg_cms_free_at_sweep;

   // Average of the bytes free at the end of the collection.

   AdaptiveWeightedAverage* _avg_cms_free;

   // Average of the bytes promoted between cms collections.

   AdaptiveWeightedAverage* _avg_cms_promo;

   // stop-the-world (STW) mark-sweep-compact

   // Average of the pause time in seconds for STW mark-sweep-compact

   // collections.

   AdaptiveWeightedAverage* _avg_msc_pause;

   // Average of the interval in seconds between STW mark-sweep-compact

   // collections.

   AdaptiveWeightedAverage* _avg_msc_interval;

   // Average of the collection costs for STW mark-sweep-compact

   // collections.

   AdaptiveWeightedAverage* _avg_msc_gc_cost;

   // Averages for mark-sweep collections.

   // The collection may have started as a background collection

   // that completes in a stop-the-world (STW) collection.

   // Average of the pause time in seconds for mark-sweep

   // collections.

   AdaptiveWeightedAverage* _avg_ms_pause;

   // Average of the interval in seconds between mark-sweep

   // collections.

   AdaptiveWeightedAverage* _avg_ms_interval;

   // Average of the collection costs for mark-sweep

   // collections.

   AdaptiveWeightedAverage* _avg_ms_gc_cost;

   // These variables contain a linear fit of

   // a generation size as the independent variable

   // and a pause time as the dependent variable.

   // For example _remark_pause_old_estimator

   // is a fit of the old generation size as the

   // independent variable and the remark pause

   // as the dependent variable.

   //   remark pause time vs. cms gen size

   LinearLeastSquareFit* _remark_pause_old_estimator;

   //   initial pause time vs. cms gen size

   LinearLeastSquareFit* _initial_pause_old_estimator;

   //   remark pause time vs. young gen size

   LinearLeastSquareFit* _remark_pause_young_estimator;

   //   initial pause time vs. young gen size

   LinearLeastSquareFit* _initial_pause_young_estimator;

   // Accessors

   int processor_count() const { return _processor_count; }

   int concurrent_processor_count() const { return _concurrent_processor_count; }

   AdaptiveWeightedAverage* avg_concurrent_time() const {

     return _avg_concurrent_time;

   }

   AdaptiveWeightedAverage* avg_concurrent_interval() const {

     return _avg_concurrent_interval;

   }

   AdaptiveWeightedAverage* avg_concurrent_gc_cost() const {

     return _avg_concurrent_gc_cost;

   }

   AdaptiveWeightedAverage* avg_cms_STW_time() const {

     return _avg_cms_STW_time;

   }

   AdaptiveWeightedAverage* avg_cms_STW_gc_cost() const {

     return _avg_cms_STW_gc_cost;

   }

   AdaptivePaddedAverage* avg_initial_pause() const {

     return _avg_initial_pause;

   }

   AdaptivePaddedAverage* avg_remark_pause() const {

     return _avg_remark_pause;

   }

   AdaptiveWeightedAverage* avg_cms_free() const {

     return _avg_cms_free;

   }

   AdaptiveWeightedAverage* avg_cms_free_at_sweep() const {

     return _avg_cms_free_at_sweep;

   }

   AdaptiveWeightedAverage* avg_msc_pause() const {

     return _avg_msc_pause;

   }

   AdaptiveWeightedAverage* avg_msc_interval() const {

     return _avg_msc_interval;

   }

   AdaptiveWeightedAverage* avg_msc_gc_cost() const {

     return _avg_msc_gc_cost;

   }

   AdaptiveWeightedAverage* avg_ms_pause() const {

     return _avg_ms_pause;

   }

   AdaptiveWeightedAverage* avg_ms_interval() const {

     return _avg_ms_interval;

   }

   AdaptiveWeightedAverage* avg_ms_gc_cost() const {

     return _avg_ms_gc_cost;

   }

   LinearLeastSquareFit* remark_pause_old_estimator() {

     return _remark_pause_old_estimator;

   }

   LinearLeastSquareFit* initial_pause_old_estimator() {

     return _initial_pause_old_estimator;

   }

   LinearLeastSquareFit* remark_pause_young_estimator() {

     return _remark_pause_young_estimator;

   }

   LinearLeastSquareFit* initial_pause_young_estimator() {

     return _initial_pause_young_estimator;

   }

   // These *slope() methods return the slope

   // m for the linear fit of an independent

   // variable vs. a dependent variable.  For

   // example

   //  remark_pause = m * old_generation_size + c

   // These may be used to determine if an

   // adjustment should be made to achieve a goal.

   // For example, if remark_pause_old_slope() is

   // positive, a reduction of the old generation

   // size has on average resulted in the reduction

   // of the remark pause.

   float remark_pause_old_slope() {

     return _remark_pause_old_estimator->slope();

   }

   float initial_pause_old_slope() {

     return _initial_pause_old_estimator->slope();

   }

   float remark_pause_young_slope() {

     return _remark_pause_young_estimator->slope();

   }

   float initial_pause_young_slope() {

     return _initial_pause_young_estimator->slope();

   }

   // Update estimators

   void update_minor_pause_old_estimator(double minor_pause_in_ms);

   // Fraction of processors used by the concurrent phases.

   double concurrent_processor_fraction();

   // Returns the total times for the concurrent part of the

   // latest collection in seconds.

   double concurrent_collection_time();

   // Return the total times for the concurrent part of the

   // latest collection in seconds where the times of the various

   // concurrent phases are scaled by the processor fraction used

   // during the phase.

   double scaled_concurrent_collection_time();

   // Dimensionless concurrent GC cost for all the concurrent phases.

   double concurrent_collection_cost(double interval_in_seconds);

   // Dimensionless GC cost

   double collection_cost(double pause_in_seconds, double interval_in_seconds);

   virtual GCPolicyKind kind() const { return _gc_cms_adaptive_size_policy; }

   virtual double time_since_major_gc() const;

   // This returns the maximum average for the concurrent, ms, and

   // msc collections.  This is meant to be used for the calculation

   // of the decayed major gc cost and is not in general the

   // average of all the different types of major collections.

   virtual double major_gc_interval_average_for_decay() const;

  public:

   CMSAdaptiveSizePolicy(size_t init_eden_size,

                         size_t init_promo_size,

                         size_t init_survivor_size,

                         double max_gc_minor_pause_sec,

                         double max_gc_pause_sec,

                         uint gc_cost_ratio);

   // The timers for the stop-the-world phases measure a total

   // stop-the-world time.  The timer is started and stopped

   // for each phase but is only reset after the final checkpoint.

   void checkpoint_roots_initial_begin();

   void checkpoint_roots_initial_end(GCCause::Cause gc_cause);

   void checkpoint_roots_final_begin();

   void checkpoint_roots_final_end(GCCause::Cause gc_cause);

   // Methods for gathering information about the

   // concurrent marking phase of the collection.

   // Records the mutator times and

   // resets the concurrent timer.

   void concurrent_marking_begin();

   // Resets concurrent phase timer in the begin methods and

   // saves the time for a phase in the end methods.

   void concurrent_marking_end();

   void concurrent_sweeping_begin();

   void concurrent_sweeping_end();

   // Similar to the above (e.g., concurrent_marking_end()) and

   // is used for both the precleaning an abortable precleaing

   // phases.

   void concurrent_precleaning_begin();

   void concurrent_precleaning_end();

   // Stops the concurrent phases time.  Gathers

   // information and resets the timer.

   void concurrent_phases_end(GCCause::Cause gc_cause,

                               size_t cur_eden,

                               size_t cur_promo);

   // Methods for gather information about STW Mark-Sweep-Compact

   void msc_collection_begin();

   void msc_collection_end(GCCause::Cause gc_cause);

   // Methods for gather information about Mark-Sweep done

   // in the foreground.

   void ms_collection_begin();

   void ms_collection_end(GCCause::Cause gc_cause);

   // Cost for a mark-sweep tenured gen collection done in the foreground

   double ms_gc_cost() const {

     return MAX2(0.0F, _avg_ms_gc_cost->average());

   }

   // Cost of collecting the tenured generation.  Includes

   // concurrent collection and STW collection costs

   double cms_gc_cost() const;

   // Cost of STW mark-sweep-compact tenured gen collection.

   double msc_gc_cost() const {

     return MAX2(0.0F, _avg_msc_gc_cost->average());

   }

   //

   double compacting_gc_cost() const {

     double result = MIN2(1.0, minor_gc_cost() + msc_gc_cost());

     assert(result >= 0.0, "Both minor and major costs are non-negative");

     return result;

   }

    // Restarts the concurrent phases timer.

    void concurrent_phases_resume();

    // Time beginning and end of the marking phase for

    // a synchronous MS collection.  A MS collection

    // that finishes in the foreground can have started

    // in the background.  These methods capture the

    // completion of the marking (after the initial

    // marking) that is done in the foreground.

    void ms_collection_marking_begin();

    void ms_collection_marking_end(GCCause::Cause gc_cause);

    static elapsedTimer* concurrent_timer_ptr() {

      return &_concurrent_timer;

    }

   AdaptiveWeightedAverage* avg_cms_promo() const {

     return _avg_cms_promo;

   }

   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;

   }

   void clear_internal_time_intervals();

   // Either calculated_promo_size_in_bytes() or promo_size()

   // should be deleted.

   size_t promo_size() { return _promo_size; }

   void set_promo_size(size_t v) { _promo_size = v; }

   // Cost of GC for all types of collections.

   virtual double gc_cost() const;

   size_t generation_alignment() { return _generation_alignment; }

   virtual void compute_young_generation_free_space(size_t cur_eden,

                                                    size_t max_eden_size);

   // Calculates new survivor space size;  returns a new tenuring threshold

   // value. Stores new survivor size in _survivor_size.

   virtual int compute_survivor_space_size_and_threshold(

                                                 bool   is_survivor_overflow,

                                                 int    tenuring_threshold,

                                                 size_t survivor_limit);

   virtual void compute_tenured_generation_free_space(size_t cur_tenured_free,

                                            size_t max_tenured_available,

                                            size_t cur_eden);

   size_t eden_decrement_aligned_down(size_t cur_eden);

   size_t eden_increment_aligned_up(size_t cur_eden);

   size_t adjust_eden_for_pause_time(size_t cur_eden);

   size_t adjust_eden_for_throughput(size_t cur_eden);

   size_t adjust_eden_for_footprint(size_t cur_eden);

   size_t promo_decrement_aligned_down(size_t cur_promo);

   size_t promo_increment_aligned_up(size_t cur_promo);

   size_t adjust_promo_for_pause_time(size_t cur_promo);

   size_t adjust_promo_for_throughput(size_t cur_promo);

   size_t adjust_promo_for_footprint(size_t cur_promo, size_t cur_eden);

   // Scale down the input size by the ratio of the cost to collect the

   // generation to the total GC cost.

   size_t scale_by_gen_gc_cost(size_t base_change, double gen_gc_cost);

   // Return the value and clear it.

   bool get_and_clear_first_after_collection();

   // Printing support

   virtual bool print_adaptive_size_policy_on(outputStream* st) const;

 };