/*

 * Copyright (c) 2001, 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.

 *

 */

// 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;

// Yes, this is a bit unpleasant... but it saves replicating the same thing

// over and over again and introducing subtle problems through small typos and

// cutting and pasting mistakes. The macros below introduces a number

// sequnce into the following two classes and the methods that access it.

#define define_num_seq(name)                                                  \

private:                                                                      \

  NumberSeq _all_##name##_times_ms;                                           \

public:                                                                       \

  void record_##name##_time_ms(double ms) {                                   \

    _all_##name##_times_ms.add(ms);                                           \

  }                                                                           \

  NumberSeq* get_##name##_seq() {                                             \

    return &_all_##name##_times_ms;                                           \

  }

class MainBodySummary;

class PauseSummary: public CHeapObj {

  define_num_seq(total)

    define_num_seq(other)

public:

  virtual MainBodySummary*    main_body_summary()    { return NULL; }

};

class MainBodySummary: public CHeapObj {

  define_num_seq(satb_drain) // optional

  define_num_seq(parallel) // parallel only

    define_num_seq(ext_root_scan)

    define_num_seq(mark_stack_scan)

    define_num_seq(update_rs)

    define_num_seq(scan_rs)

    define_num_seq(obj_copy)

    define_num_seq(termination) // parallel only

    define_num_seq(parallel_other) // parallel only

  define_num_seq(mark_closure)

  define_num_seq(clear_ct)  // parallel only

};

class Summary: public PauseSummary,

               public MainBodySummary {

public:

  virtual MainBodySummary*    main_body_summary()    { return this; }

};

class G1CollectorPolicy: public CollectorPolicy {

protected:

  // The number of pauses during the execution.

  long _n_pauses;

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

  // has been set, or 1 otherwise

  int _parallel_gc_threads;

  enum SomePrivateConstants {

    NumPrevPausesForHeuristics = 10

  };

  G1MMUTracker* _mmu_tracker;

  void initialize_flags();

  void initialize_all() {

    initialize_flags();

    initialize_size_info();

    initialize_perm_generation(PermGen::MarkSweepCompact);

  }

  virtual size_t default_init_heap_size() {

    // Pick some reasonable default.

    return 8*M;

  }

  double _cur_collection_start_sec;

  size_t _cur_collection_pause_used_at_start_bytes;

  size_t _cur_collection_pause_used_regions_at_start;

  size_t _prev_collection_pause_used_at_end_bytes;

  double _cur_collection_par_time_ms;

  double _cur_satb_drain_time_ms;

  double _cur_clear_ct_time_ms;

  bool   _satb_drain_time_set;

#ifndef PRODUCT

  // Card Table Count Cache stats

  double _min_clear_cc_time_ms;         // min

  double _max_clear_cc_time_ms;         // max

  double _cur_clear_cc_time_ms;         // clearing time during current pause

  double _cum_clear_cc_time_ms;         // cummulative clearing time

  jlong  _num_cc_clears;                // number of times the card count cache has been cleared

#endif

  double _cur_CH_strong_roots_end_sec;

  double _cur_CH_strong_roots_dur_ms;

  double _cur_G1_strong_roots_end_sec;

  double _cur_G1_strong_roots_dur_ms;

  // Statistics for recent GC pauses.  See below for how indexed.

  TruncatedSeq* _recent_CH_strong_roots_times_ms;

  TruncatedSeq* _recent_G1_strong_roots_times_ms;

  TruncatedSeq* _recent_evac_times_ms;

  // These exclude marking times.

  TruncatedSeq* _recent_pause_times_ms;

  TruncatedSeq* _recent_gc_times_ms;

  TruncatedSeq* _recent_CS_bytes_used_before;

  TruncatedSeq* _recent_CS_bytes_surviving;

  TruncatedSeq* _recent_rs_sizes;

  TruncatedSeq* _concurrent_mark_init_times_ms;

  TruncatedSeq* _concurrent_mark_remark_times_ms;

  TruncatedSeq* _concurrent_mark_cleanup_times_ms;

  Summary*           _summary;

  NumberSeq* _all_pause_times_ms;

  NumberSeq* _all_full_gc_times_ms;

  double _stop_world_start;

  NumberSeq* _all_stop_world_times_ms;

  NumberSeq* _all_yield_times_ms;

  size_t     _region_num_young;

  size_t     _region_num_tenured;

  size_t     _prev_region_num_young;

  size_t     _prev_region_num_tenured;

  NumberSeq* _all_mod_union_times_ms;

  int        _aux_num;

  NumberSeq* _all_aux_times_ms;

  double*    _cur_aux_start_times_ms;

  double*    _cur_aux_times_ms;

  bool*      _cur_aux_times_set;

  double* _par_last_gc_worker_start_times_ms;

  double* _par_last_ext_root_scan_times_ms;

  double* _par_last_mark_stack_scan_times_ms;

  double* _par_last_update_rs_times_ms;

  double* _par_last_update_rs_processed_buffers;

  double* _par_last_scan_rs_times_ms;

  double* _par_last_obj_copy_times_ms;

  double* _par_last_termination_times_ms;

  double* _par_last_termination_attempts;

  double* _par_last_gc_worker_end_times_ms;

  // indicates that we are in young GC mode

  bool _in_young_gc_mode;

  // indicates whether we are in full young or partially young GC mode

  bool _full_young_gcs;

  // if true, then it tries to dynamically adjust the length of the

  // young list

  bool _adaptive_young_list_length;

  size_t _young_list_min_length;

  size_t _young_list_target_length;

  size_t _young_list_fixed_length;

  size_t _young_cset_length;

  bool   _last_young_gc_full;

  unsigned              _full_young_pause_num;

  unsigned              _partial_young_pause_num;

  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;

  bool during_marking() {

    return _during_marking;

  }

  // <NEW PREDICTION>

private:

  enum PredictionConstants {

    TruncatedSeqLength = 10

  };

  TruncatedSeq* _alloc_rate_ms_seq;

  double        _prev_collection_pause_end_ms;

  TruncatedSeq* _pending_card_diff_seq;

  TruncatedSeq* _rs_length_diff_seq;

  TruncatedSeq* _cost_per_card_ms_seq;

  TruncatedSeq* _fully_young_cards_per_entry_ratio_seq;

  TruncatedSeq* _partially_young_cards_per_entry_ratio_seq;

  TruncatedSeq* _cost_per_entry_ms_seq;

  TruncatedSeq* _partially_young_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* _scanned_cards_seq;

  TruncatedSeq* _rs_lengths_seq;

  TruncatedSeq* _cost_per_byte_ms_during_cm_seq;

  TruncatedSeq* _young_gc_eff_seq;

  TruncatedSeq* _max_conc_overhead_seq;

  size_t _recorded_young_regions;

  size_t _recorded_non_young_regions;

  size_t _recorded_region_num;

  size_t _free_regions_at_end_of_collection;

  size_t _recorded_rs_lengths;

  size_t _max_rs_lengths;

  size_t _recorded_marked_bytes;

  size_t _recorded_young_bytes;

  size_t _predicted_pending_cards;

  size_t _predicted_cards_scanned;

  size_t _predicted_rs_lengths;

  size_t _predicted_bytes_to_copy;

  double _predicted_survival_ratio;

  double _predicted_rs_update_time_ms;

  double _predicted_rs_scan_time_ms;

  double _predicted_object_copy_time_ms;

  double _predicted_constant_other_time_ms;

  double _predicted_young_other_time_ms;

  double _predicted_non_young_other_time_ms;

  double _predicted_pause_time_ms;

  double _vtime_diff_ms;

  double _recorded_young_free_cset_time_ms;

  double _recorded_non_young_free_cset_time_ms;

  double _sigma;

  double _expensive_region_limit_ms;

  size_t _rs_lengths_prediction;

  size_t _known_garbage_bytes;

  double _known_garbage_ratio;

  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);

protected:

  double _pause_time_target_ms;

  double _recorded_young_cset_choice_time_ms;

  double _recorded_non_young_cset_choice_time_ms;

  bool   _within_target;

  size_t _pending_cards;

  size_t _max_pending_cards;

public:

  void set_region_short_lived(HeapRegion* hr) {

    hr->install_surv_rate_group(_short_lived_surv_rate_group);

  }

  void set_region_survivors(HeapRegion* hr) {

    hr->install_surv_rate_group(_survivor_surv_rate_group);

  }

#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()));

  }

  size_t young_cset_length() {

    return _young_cset_length;

  }

  void record_max_rs_lengths(size_t rs_lengths) {

    _max_rs_lengths = rs_lengths;

  }

  size_t predict_pending_card_diff() {

    double prediction = get_new_neg_prediction(_pending_card_diff_seq);

    if (prediction < 0.00001)

      return 0;

    else

      return (size_t) prediction;

  }

  size_t predict_pending_cards() {

    size_t max_pending_card_num = _g1->max_pending_card_num();

    size_t diff = predict_pending_card_diff();

    size_t prediction;

    if (diff > max_pending_card_num)

      prediction = max_pending_card_num;

    else

      prediction = max_pending_card_num - diff;

    return prediction;

  }

  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_fully_young_cards_per_entry_ratio() {

    return get_new_prediction(_fully_young_cards_per_entry_ratio_seq);

  }

  double predict_partially_young_cards_per_entry_ratio() {

    if (_partially_young_cards_per_entry_ratio_seq->num() < 2)

      return predict_fully_young_cards_per_entry_ratio();

    else

      return get_new_prediction(_partially_young_cards_per_entry_ratio_seq);

  }

  size_t predict_young_card_num(size_t rs_length) {

    return (size_t) ((double) rs_length *

                     predict_fully_young_cards_per_entry_ratio());

  }

  size_t predict_non_young_card_num(size_t rs_length) {

    return (size_t) ((double) rs_length *

                     predict_partially_young_cards_per_entry_ratio());

  }

  double predict_rs_scan_time_ms(size_t card_num) {

    if (full_young_gcs())

      return (double) card_num * get_new_prediction(_cost_per_entry_ms_seq);

    else

      return predict_partially_young_rs_scan_time_ms(card_num);

  }

  double predict_partially_young_rs_scan_time_ms(size_t card_num) {

    if (_partially_young_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(_partially_young_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);

  }

  void check_if_region_is_too_expensive(double predicted_time_ms);

  double predict_young_collection_elapsed_time_ms(size_t adjustment);

  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 young);

    // for use by: calculate_young_list_target_length(rs_length)

  bool predict_will_fit(size_t young_region_num,

                        double base_time_ms,

                        size_t init_free_regions,

                        double target_pause_time_ms);

  void start_recording_regions();

  void record_cset_region_info(HeapRegion* hr, bool young);

  void record_non_young_cset_region(HeapRegion* hr);

  void set_recorded_young_regions(size_t n_regions);

  void set_recorded_young_bytes(size_t bytes);

  void set_recorded_rs_lengths(size_t rs_lengths);

  void set_predicted_bytes_to_copy(size_t bytes);

  void end_recording_regions();

  void record_vtime_diff_ms(double vtime_diff_ms) {

    _vtime_diff_ms = vtime_diff_ms;

  }

  void record_young_free_cset_time_ms(double time_ms) {

    _recorded_young_free_cset_time_ms = time_ms;

  }

  void record_non_young_free_cset_time_ms(double time_ms) {

    _recorded_non_young_free_cset_time_ms = time_ms;

  }

  double predict_young_gc_eff() {

    return get_new_neg_prediction(_young_gc_eff_seq);

  }

  double predict_survivor_regions_evac_time();

  // </NEW PREDICTION>

public:

  void cset_regions_freed() {

    bool propagate = _last_young_gc_full && !_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

  }

  void set_known_garbage_bytes(size_t known_garbage_bytes) {

    _known_garbage_bytes = known_garbage_bytes;

    size_t heap_bytes = _g1->capacity();

    _known_garbage_ratio = (double) _known_garbage_bytes / (double) heap_bytes;

  }

  void decrease_known_garbage_bytes(size_t known_garbage_bytes) {

    guarantee( _known_garbage_bytes >= known_garbage_bytes, "invariant" );

    _known_garbage_bytes -= known_garbage_bytes;

    size_t heap_bytes = _g1->capacity();

    _known_garbage_ratio = (double) _known_garbage_bytes / (double) heap_bytes;

  }

  G1MMUTracker* mmu_tracker() {

    return _mmu_tracker;

  }

  double max_pause_time_ms() {

    return _mmu_tracker->max_gc_time() * 1000.0;

  }