/*

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 * published by the Free Software Foundation.

 *

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 * 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.

 *

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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTORPOLICY_HPP

#define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTORPOLICY_HPP

#include "gc_implementation/g1/collectionSetChooser.hpp"

#include "gc_implementation/g1/g1MMUTracker.hpp"

#include "memory/collectorPolicy.hpp"

// A G1CollectorPolicy makes policy decisions that determine the

// characteristics of the collector.  Examples include:

//   * choice of collection set.

//   * when to collect.

class HeapRegion;

class CollectionSetChooser;

class G1GCPhaseTimes;

// TraceGen0Time collects data on _both_ young and mixed evacuation pauses

// (the latter may contain non-young regions - i.e. regions that are

// technically in Gen1) while TraceGen1Time collects data about full GCs.

class TraceGen0TimeData : public CHeapObj<mtGC> {

 private:

  unsigned  _young_pause_num;

  unsigned  _mixed_pause_num;

  NumberSeq _all_stop_world_times_ms;

  NumberSeq _all_yield_times_ms;

  NumberSeq _total;

  NumberSeq _other;

  NumberSeq _root_region_scan_wait;

  NumberSeq _parallel;

  NumberSeq _ext_root_scan;

  NumberSeq _satb_filtering;

  NumberSeq _update_rs;

  NumberSeq _scan_rs;

  NumberSeq _obj_copy;

  NumberSeq _termination;

  NumberSeq _parallel_other;

  NumberSeq _clear_ct;

  void print_summary(const char* str, const NumberSeq* seq) const;

  void print_summary_sd(const char* str, const NumberSeq* seq) const;

public:

   TraceGen0TimeData() : _young_pause_num(0), _mixed_pause_num(0) {};

  void record_start_collection(double time_to_stop_the_world_ms);

  void record_yield_time(double yield_time_ms);

  void record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times);

  void increment_young_collection_count();

  void increment_mixed_collection_count();

  void print() const;

};

class TraceGen1TimeData : public CHeapObj<mtGC> {

 private:

  NumberSeq _all_full_gc_times;

 public:

  void record_full_collection(double full_gc_time_ms);

  void print() const;

};

// There are three command line options related to the young gen size:

// NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is

// just a short form for NewSize==MaxNewSize). G1 will use its internal

// heuristics to calculate the actual young gen size, so these options

// basically only limit the range within which G1 can pick a young gen

// size. Also, these are general options taking byte sizes. G1 will

// internally work with a number of regions instead. So, some rounding

// will occur.

//

// If nothing related to the the young gen size is set on the command

// line we should allow the young gen to be between G1NewSizePercent

// and G1MaxNewSizePercent of the heap size. This means that every time

// the heap size changes, the limits for the young gen size will be

// recalculated.

//

// If only -XX:NewSize is set we should use the specified value as the

// minimum size for young gen. Still using G1MaxNewSizePercent of the

// heap as maximum.

//

// If only -XX:MaxNewSize is set we should use the specified value as the

// maximum size for young gen. Still using G1NewSizePercent of the heap

// as minimum.

//

// If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.

// No updates when the heap size changes. There is a special case when

// NewSize==MaxNewSize. This is interpreted as "fixed" and will use a

// different heuristic for calculating the collection set when we do mixed

// collection.

//

// If only -XX:NewRatio is set we should use the specified ratio of the heap

// as both min and max. This will be interpreted as "fixed" just like the

// NewSize==MaxNewSize case above. But we will update the min and max

// everytime the heap size changes.

//

// NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is

// combined with either NewSize or MaxNewSize. (A warning message is printed.)

class G1YoungGenSizer : public CHeapObj<mtGC> {

private:

  enum SizerKind {

    SizerDefaults,

    SizerNewSizeOnly,

    SizerMaxNewSizeOnly,

    SizerMaxAndNewSize,

    SizerNewRatio

  };

  SizerKind _sizer_kind;

  uint _min_desired_young_length;

  uint _max_desired_young_length;

  bool _adaptive_size;

  uint calculate_default_min_length(uint new_number_of_heap_regions);

  uint calculate_default_max_length(uint new_number_of_heap_regions);

public:

  G1YoungGenSizer();

  void heap_size_changed(uint new_number_of_heap_regions);

  uint min_desired_young_length() {

    return _min_desired_young_length;

  }

  uint max_desired_young_length() {

    return _max_desired_young_length;

  }

  bool adaptive_young_list_length() {

    return _adaptive_size;

  }

};

class G1CollectorPolicy: public CollectorPolicy {

private:

  // either equal to the number of parallel threads, if ParallelGCThreads

  // has been set, or 1 otherwise

  int _parallel_gc_threads;

  // The number of GC threads currently active.

  uintx _no_of_gc_threads;

  enum SomePrivateConstants {

    NumPrevPausesForHeuristics = 10

  };

  G1MMUTracker* _mmu_tracker;

  void initialize_flags();

  CollectionSetChooser* _collectionSetChooser;

  double _full_collection_start_sec;

  uint   _cur_collection_pause_used_regions_at_start;

  // These exclude marking times.

  TruncatedSeq* _recent_gc_times_ms;

  TruncatedSeq* _concurrent_mark_remark_times_ms;

  TruncatedSeq* _concurrent_mark_cleanup_times_ms;

  TraceGen0TimeData _trace_gen0_time_data;

  TraceGen1TimeData _trace_gen1_time_data;

  double _stop_world_start;

  // indicates whether we are in young or mixed GC mode

  bool _gcs_are_young;

  uint _young_list_target_length;

  uint _young_list_fixed_length;

  // The max number of regions we can extend the eden by while the GC

  // locker is active. This should be >= _young_list_target_length;

  uint _young_list_max_length;

  bool                  _last_gc_was_young;

  bool                  _during_marking;

  bool                  _in_marking_window;

  bool                  _in_marking_window_im;

  SurvRateGroup*        _short_lived_surv_rate_group;

  SurvRateGroup*        _survivor_surv_rate_group;

  // add here any more surv rate groups

  double                _gc_overhead_perc;

  double _reserve_factor;

  uint _reserve_regions;

  bool during_marking() {

    return _during_marking;

  }

  enum PredictionConstants {

    TruncatedSeqLength = 10

  };

  TruncatedSeq* _alloc_rate_ms_seq;

  double        _prev_collection_pause_end_ms;

  TruncatedSeq* _rs_length_diff_seq;

  TruncatedSeq* _cost_per_card_ms_seq;

  TruncatedSeq* _young_cards_per_entry_ratio_seq;

  TruncatedSeq* _mixed_cards_per_entry_ratio_seq;

  TruncatedSeq* _cost_per_entry_ms_seq;

  TruncatedSeq* _mixed_cost_per_entry_ms_seq;

  TruncatedSeq* _cost_per_byte_ms_seq;

  TruncatedSeq* _constant_other_time_ms_seq;

  TruncatedSeq* _young_other_cost_per_region_ms_seq;

  TruncatedSeq* _non_young_other_cost_per_region_ms_seq;

  TruncatedSeq* _pending_cards_seq;

  TruncatedSeq* _rs_lengths_seq;

  TruncatedSeq* _cost_per_byte_ms_during_cm_seq;

  G1YoungGenSizer* _young_gen_sizer;

  uint _eden_cset_region_length;

  uint _survivor_cset_region_length;

  uint _old_cset_region_length;

  void init_cset_region_lengths(uint eden_cset_region_length,

                                uint survivor_cset_region_length);

  uint eden_cset_region_length()     { return _eden_cset_region_length;     }

  uint survivor_cset_region_length() { return _survivor_cset_region_length; }

  uint old_cset_region_length()      { return _old_cset_region_length;      }

  uint _free_regions_at_end_of_collection;

  size_t _recorded_rs_lengths;

  size_t _max_rs_lengths;

  double _sigma;

  size_t _rs_lengths_prediction;

  double sigma() { return _sigma; }

  // A function that prevents us putting too much stock in small sample

  // sets.  Returns a number between 2.0 and 1.0, depending on the number

  // of samples.  5 or more samples yields one; fewer scales linearly from

  // 2.0 at 1 sample to 1.0 at 5.

  double confidence_factor(int samples) {

    if (samples > 4) return 1.0;

    else return  1.0 + sigma() * ((double)(5 - samples))/2.0;

  }

  double get_new_neg_prediction(TruncatedSeq* seq) {

    return seq->davg() - sigma() * seq->dsd();

  }

#ifndef PRODUCT

  bool verify_young_ages(HeapRegion* head, SurvRateGroup *surv_rate_group);

#endif // PRODUCT

  void adjust_concurrent_refinement(double update_rs_time,

                                    double update_rs_processed_buffers,

                                    double goal_ms);

  uintx no_of_gc_threads() { return _no_of_gc_threads; }

  void set_no_of_gc_threads(uintx v) { _no_of_gc_threads = v; }

  double _pause_time_target_ms;

  size_t _pending_cards;

public:

  // Accessors

  void set_region_eden(HeapRegion* hr, int young_index_in_cset) {

    hr->set_young();

    hr->install_surv_rate_group(_short_lived_surv_rate_group);

    hr->set_young_index_in_cset(young_index_in_cset);

  }

  void set_region_survivor(HeapRegion* hr, int young_index_in_cset) {

    assert(hr->is_young() && hr->is_survivor(), "pre-condition");

    hr->install_surv_rate_group(_survivor_surv_rate_group);

    hr->set_young_index_in_cset(young_index_in_cset);

  }

#ifndef PRODUCT

  bool verify_young_ages();

#endif // PRODUCT

  double get_new_prediction(TruncatedSeq* seq) {

    return MAX2(seq->davg() + sigma() * seq->dsd(),

                seq->davg() * confidence_factor(seq->num()));

  }

  void record_max_rs_lengths(size_t rs_lengths) {

    _max_rs_lengths = rs_lengths;

  }

  size_t predict_rs_length_diff() {

    return (size_t) get_new_prediction(_rs_length_diff_seq);

  }

  double predict_alloc_rate_ms() {

    return get_new_prediction(_alloc_rate_ms_seq);

  }

  double predict_cost_per_card_ms() {

    return get_new_prediction(_cost_per_card_ms_seq);

  }

  double predict_rs_update_time_ms(size_t pending_cards) {

    return (double) pending_cards * predict_cost_per_card_ms();

  }

  double predict_young_cards_per_entry_ratio() {

    return get_new_prediction(_young_cards_per_entry_ratio_seq);

  }

  double predict_mixed_cards_per_entry_ratio() {

    if (_mixed_cards_per_entry_ratio_seq->num() < 2) {

      return predict_young_cards_per_entry_ratio();

    } else {

      return get_new_prediction(_mixed_cards_per_entry_ratio_seq);

    }

  }

  size_t predict_young_card_num(size_t rs_length) {

    return (size_t) ((double) rs_length *

                     predict_young_cards_per_entry_ratio());

  }

  size_t predict_non_young_card_num(size_t rs_length) {

    return (size_t) ((double) rs_length *

                     predict_mixed_cards_per_entry_ratio());

  }

  double predict_rs_scan_time_ms(size_t card_num) {

    if (gcs_are_young()) {

      return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq);

    } else {

      return predict_mixed_rs_scan_time_ms(card_num);

    }

  }

  double predict_mixed_rs_scan_time_ms(size_t card_num) {

    if (_mixed_cost_per_entry_ms_seq->num() < 3) {

      return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq);

    } else {

      return (double) (card_num *

                       get_new_prediction(_mixed_cost_per_entry_ms_seq));

    }

  }

  double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) {

    if (_cost_per_byte_ms_during_cm_seq->num() < 3) {

      return (1.1 * (double) bytes_to_copy) *

              get_new_prediction(_cost_per_byte_ms_seq);

    } else {

      return (double) bytes_to_copy *

             get_new_prediction(_cost_per_byte_ms_during_cm_seq);

    }

  }

  double predict_object_copy_time_ms(size_t bytes_to_copy) {

    if (_in_marking_window && !_in_marking_window_im) {

      return predict_object_copy_time_ms_during_cm(bytes_to_copy);

    } else {

      return (double) bytes_to_copy *

              get_new_prediction(_cost_per_byte_ms_seq);

    }

  }

  double predict_constant_other_time_ms() {

    return get_new_prediction(_constant_other_time_ms_seq);

  }

  double predict_young_other_time_ms(size_t young_num) {

    return (double) young_num *

           get_new_prediction(_young_other_cost_per_region_ms_seq);

  }

  double predict_non_young_other_time_ms(size_t non_young_num) {

    return (double) non_young_num *

           get_new_prediction(_non_young_other_cost_per_region_ms_seq);

  }

  double predict_base_elapsed_time_ms(size_t pending_cards);

  double predict_base_elapsed_time_ms(size_t pending_cards,

                                      size_t scanned_cards);

  size_t predict_bytes_to_copy(HeapRegion* hr);

  double predict_region_elapsed_time_ms(HeapRegion* hr, bool for_young_gc);

  void set_recorded_rs_lengths(size_t rs_lengths);

  uint cset_region_length()       { return young_cset_region_length() +

                                           old_cset_region_length(); }

  uint young_cset_region_length() { return eden_cset_region_length() +

                                           survivor_cset_region_length(); }

  double predict_survivor_regions_evac_time();

  void cset_regions_freed() {

    bool propagate = _last_gc_was_young && !_in_marking_window;

    _short_lived_surv_rate_group->all_surviving_words_recorded(propagate);

    _survivor_surv_rate_group->all_surviving_words_recorded(propagate);

    // also call it on any more surv rate groups

  }

  G1MMUTracker* mmu_tracker() {

    return _mmu_tracker;

  }

  double max_pause_time_ms() {

    return _mmu_tracker->max_gc_time() * 1000.0;

  }

  double predict_remark_time_ms() {

    return get_new_prediction(_concurrent_mark_remark_times_ms);

  }

  double predict_cleanup_time_ms() {

    return get_new_prediction(_concurrent_mark_cleanup_times_ms);

  }

  // Returns an estimate of the survival rate of the region at yg-age

  // "yg_age".

  double predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) {

    TruncatedSeq* seq = surv_rate_group->get_seq(age);

    if (seq->num() == 0)

      gclog_or_tty->print("BARF! age is %d", age);

    guarantee( seq->num() > 0, "invariant" );

    double pred = get_new_prediction(seq);

    if (pred > 1.0)

      pred = 1.0;

    return pred;

  }

  double predict_yg_surv_rate(int age) {

    return predict_yg_surv_rate(age, _short_lived_surv_rate_group);

  }

  double accum_yg_surv_rate_pred(int age) {

    return _short_lived_surv_rate_group->accum_surv_rate_pred(age);

  }

private:

  // Statistics kept per GC stoppage, pause or full.

  TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;

  // Add a new GC of the given duration and end time to the record.

  void update_recent_gc_times(double end_time_sec, double elapsed_ms);

  // The head of the list (via "next_in_collection_set()") representing the

  // current collection set. Set from the incrementally built collection

  // set at the start of the pause.

  HeapRegion* _collection_set;

  // The number of bytes in the collection set before the pause. Set from

  // the incrementally built collection set at the start of an evacuation

  // pause, and incremented in finalize_cset() when adding old regions

  // (if any) to the collection set.

  size_t _collection_set_bytes_used_before;

  // The number of bytes copied during the GC.

  size_t _bytes_copied_during_gc;

  // The associated information that is maintained while the incremental

  // collection set is being built with young regions. Used to populate

  // the recorded info for the evacuation pause.

  enum CSetBuildType {

    Active,             // We are actively building the collection set

    Inactive            // We are not actively building the collection set

  };