--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp	Thu Jun 05 15:57:56 2008 -0700
@@ -0,0 +1,1199 @@
+/*
+ * Copyright 2001-2007 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.
+ *
+ */
+
+// 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 PopPreambleSummary;
+
+class PauseSummary {
+  define_num_seq(total)
+    define_num_seq(other)
+
+public:
+  virtual MainBodySummary*    main_body_summary()    { return NULL; }
+  virtual PopPreambleSummary* pop_preamble_summary() { return NULL; }
+};
+
+class MainBodySummary {
+  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(scan_only)
+    define_num_seq(update_rs)
+    define_num_seq(scan_rs)
+    define_num_seq(scan_new_refs) // Only for temp use; added to
+                                  // in parallel case.
+    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 PopPreambleSummary {
+  define_num_seq(pop_preamble)
+    define_num_seq(pop_update_rs)
+    define_num_seq(pop_scan_rs)
+    define_num_seq(pop_closure_app)
+    define_num_seq(pop_evacuation)
+    define_num_seq(pop_other)
+};
+
+class NonPopSummary: public PauseSummary,
+                     public MainBodySummary {
+public:
+  virtual MainBodySummary*    main_body_summary()    { return this; }
+};
+
+class PopSummary: public PauseSummary,
+                  public MainBodySummary,
+                  public PopPreambleSummary {
+public:
+  virtual MainBodySummary*    main_body_summary()    { return this; }
+  virtual PopPreambleSummary* pop_preamble_summary() { return this; }
+};
+
+class NonPopAbandonedSummary: public PauseSummary {
+};
+
+class PopAbandonedSummary: public PauseSummary,
+                           public PopPreambleSummary {
+public:
+  virtual PopPreambleSummary* pop_preamble_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,
+    NumPrevGCsForHeuristics = 10,
+    NumAPIs = HeapRegion::MaxAge
+  };
+
+  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;
+  double _cur_popular_preamble_start_ms;
+  double _cur_popular_preamble_time_ms;
+  double _cur_popular_compute_rc_time_ms;
+  double _cur_popular_evac_time_ms;
+
+  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;
+
+  NonPopSummary*           _non_pop_summary;
+  PopSummary*              _pop_summary;
+  NonPopAbandonedSummary*  _non_pop_abandoned_summary;
+  PopAbandonedSummary*     _pop_abandoned_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_ext_root_scan_times_ms;
+  double* _par_last_mark_stack_scan_times_ms;
+  double* _par_last_scan_only_times_ms;
+  double* _par_last_scan_only_regions_scanned;
+  double* _par_last_update_rs_start_times_ms;
+  double* _par_last_update_rs_times_ms;
+  double* _par_last_update_rs_processed_buffers;
+  double* _par_last_scan_rs_start_times_ms;
+  double* _par_last_scan_rs_times_ms;
+  double* _par_last_scan_new_refs_times_ms;
+  double* _par_last_obj_copy_times_ms;
+  double* _par_last_termination_times_ms;
+
+  // there are two pases during popular pauses, so we need to store
+  // somewhere the results of the first pass
+  double* _pop_par_last_update_rs_start_times_ms;
+  double* _pop_par_last_update_rs_times_ms;
+  double* _pop_par_last_update_rs_processed_buffers;
+  double* _pop_par_last_scan_rs_start_times_ms;
+  double* _pop_par_last_scan_rs_times_ms;
+  double* _pop_par_last_closure_app_times_ms;
+
+  double _pop_compute_rc_start;
+  double _pop_evac_start;
+
+  // 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_so_prefix_length;
+  size_t _young_list_fixed_length;
+
+  size_t _young_cset_length;
+  bool   _last_young_gc_full;
+
+  double _target_pause_time_ms;
+
+  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
+
+  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* _cost_per_scan_only_region_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* _cost_per_scan_only_region_ms_during_cm_seq;
+
+  TruncatedSeq* _young_gc_eff_seq;
+
+  TruncatedSeq* _max_conc_overhead_seq;
+
+  size_t _recorded_young_regions;
+  size_t _recorded_scan_only_regions;
+  size_t _recorded_non_young_regions;
+  size_t _recorded_region_num;
+
+  size_t _free_regions_at_end_of_collection;
+  size_t _scan_only_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_scan_only_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
+
+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
+
+  void tag_scan_only(size_t short_lived_scan_only_length);
+
+  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_scan_only_time_ms_during_cm(size_t scan_only_region_num) {
+    if (_cost_per_scan_only_region_ms_during_cm_seq->num() < 3)
+      return 1.5 * (double) scan_only_region_num *
+        get_new_prediction(_cost_per_scan_only_region_ms_seq);
+    else
+      return (double) scan_only_region_num *
+        get_new_prediction(_cost_per_scan_only_region_ms_during_cm_seq);
+  }
+
+  double predict_scan_only_time_ms(size_t scan_only_region_num) {
+    if (_in_marking_window_im)
+      return predict_scan_only_time_ms_during_cm(scan_only_region_num);
+    else
+      return (double) scan_only_region_num *
+        get_new_prediction(_cost_per_scan_only_region_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_optimal_so_length(length)
+  void predict_gc_eff(size_t young_region_num,
+                      size_t so_length,
+                      double base_time_ms,
+                      double *gc_eff,
+                      double *pause_time_ms);
+
+  // for use by: calculate_young_list_target_config(rs_length)
+  bool predict_gc_eff(size_t young_region_num,
+                      size_t so_length,
+                      double base_time_with_so_ms,
+                      size_t init_free_regions,
+                      double target_pause_time_ms,
+                      double* gc_eff);
+
+  void start_recording_regions();
+  void record_cset_region(HeapRegion* hr, bool young);
+  void record_scan_only_regions(size_t scan_only_length);
+  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);
+  }
+
+  // </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 predict_init_time_ms() {
+    return get_new_prediction(_concurrent_mark_init_times_ms);
+  }
+
+  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) {
+    TruncatedSeq* seq = _short_lived_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 accum_yg_surv_rate_pred(int age) {
+    return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
+  }
+
+protected:
+  void print_stats (int level, const char* str, double value);
+  void print_stats (int level, const char* str, int value);
+  void print_par_stats (int level, const char* str, double* data) {
+    print_par_stats(level, str, data, true);
+  }
+  void print_par_stats (int level, const char* str, double* data, bool summary);
+  void print_par_buffers (int level, const char* str, double* data, bool summary);
+
+  void check_other_times(int level,
+                         NumberSeq* other_times_ms,
+                         NumberSeq* calc_other_times_ms) const;
+
+  void print_summary (PauseSummary* stats) const;
+  void print_abandoned_summary(PauseSummary* non_pop_summary,
+                               PauseSummary* pop_summary) const;
+
+  void print_summary (int level, const char* str, NumberSeq* seq) const;
+  void print_summary_sd (int level, const char* str, NumberSeq* seq) const;
+
+  double avg_value (double* data);
+  double max_value (double* data);
+  double sum_of_values (double* data);
+  double max_sum (double* data1, double* data2);
+
+  int _last_satb_drain_processed_buffers;
+  int _last_update_rs_processed_buffers;
+  double _last_pause_time_ms;
+
+  size_t _bytes_in_to_space_before_gc;
+  size_t _bytes_in_to_space_after_gc;
+  size_t bytes_in_to_space_during_gc() {
+    return
+      _bytes_in_to_space_after_gc - _bytes_in_to_space_before_gc;
+  }
+  size_t _bytes_in_collection_set_before_gc;
+  // Used to count used bytes in CS.
+  friend class CountCSClosure;
+
+  // Statistics kept per GC stoppage, pause or full.
+  TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
+
+  // We track markings.
+  int _num_markings;
+  double _mark_thread_startup_sec;       // Time at startup of marking thread
+
+  // 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.
+  HeapRegion* _collection_set;
+  size_t _collection_set_size;
+  size_t _collection_set_bytes_used_before;
+
+  // Info about marking.
+  int _n_marks; // Sticky at 2, so we know when we've done at least 2.
+
+  // The number of collection pauses at the end of the last mark.
+  size_t _n_pauses_at_mark_end;
+
+  // ==== This section is for stats related to starting Conc Refinement on time.
+  size_t _conc_refine_enabled;
+  size_t _conc_refine_zero_traversals;
+  size_t _conc_refine_max_traversals;
+  // In # of heap regions.
+  size_t _conc_refine_current_delta;
+
+  // At the beginning of a collection pause, update the variables above,
+  // especially the "delta".
+  void update_conc_refine_data();
+  // ====
+
+  // Stash a pointer to the g1 heap.
+  G1CollectedHeap* _g1;
+
+  // The average time in ms per collection pause, averaged over recent pauses.
+  double recent_avg_time_for_pauses_ms();
+
+  // The average time in ms for processing CollectedHeap strong roots, per
+  // collection pause, averaged over recent pauses.
+  double recent_avg_time_for_CH_strong_ms();
+
+  // The average time in ms for processing the G1 remembered set, per
+  // pause, averaged over recent pauses.
+  double recent_avg_time_for_G1_strong_ms();
+
+  // The average time in ms for "evacuating followers", per pause, averaged
+  // over recent pauses.
+  double recent_avg_time_for_evac_ms();
+
+  // The number of "recent" GCs recorded in the number sequences
+  int number_of_recent_gcs();
+
+  // The average survival ratio, computed by the total number of bytes
+  // suriviving / total number of bytes before collection over the last
+  // several recent pauses.
+  double recent_avg_survival_fraction();
+  // The survival fraction of the most recent pause; if there have been no
+  // pauses, returns 1.0.
+  double last_survival_fraction();
+
+  // Returns a "conservative" estimate of the recent survival rate, i.e.,
+  // one that may be higher than "recent_avg_survival_fraction".
+  // This is conservative in several ways:
+  //   If there have been few pauses, it will assume a potential high
+  //     variance, and err on the side of caution.
+  //   It puts a lower bound (currently 0.1) on the value it will return.
+  //   To try to detect phase changes, if the most recent pause ("latest") has a
+  //     higher-than average ("avg") survival rate, it returns that rate.
+  // "work" version is a utility function; young is restricted to young regions.
+  double conservative_avg_survival_fraction_work(double avg,
+                                                 double latest);
+
+  // The arguments are the two sequences that keep track of the number of bytes
+  //   surviving and the total number of bytes before collection, resp.,
+  //   over the last evereal recent pauses
+  // Returns the survival rate for the category in the most recent pause.
+  // If there have been no pauses, returns 1.0.
+  double last_survival_fraction_work(TruncatedSeq* surviving,
+                                     TruncatedSeq* before);
+
+  // The arguments are the two sequences that keep track of the number of bytes
+  //   surviving and the total number of bytes before collection, resp.,
+  //   over the last several recent pauses
+  // Returns the average survival ration over the last several recent pauses
+  // If there have been no pauses, return 1.0
+  double recent_avg_survival_fraction_work(TruncatedSeq* surviving,
+                                           TruncatedSeq* before);
+
+  double conservative_avg_survival_fraction() {
+    double avg = recent_avg_survival_fraction();
+    double latest = last_survival_fraction();
+    return conservative_avg_survival_fraction_work(avg, latest);
+  }
+
+  // The ratio of gc time to elapsed time, computed over recent pauses.
+  double _recent_avg_pause_time_ratio;
+
+  double recent_avg_pause_time_ratio() {
+    return _recent_avg_pause_time_ratio;
+  }
+
+  // Number of pauses between concurrent marking.
+  size_t _pauses_btwn_concurrent_mark;
+
+  size_t _n_marks_since_last_pause;
+
+  // True iff CM has been initiated.
+  bool _conc_mark_initiated;
+
+  // True iff CM should be initiated
+  bool _should_initiate_conc_mark;
+  bool _should_revert_to_full_young_gcs;
+  bool _last_full_young_gc;
+
+  // This set of variables tracks the collector efficiency, in order to
+  // determine whether we should initiate a new marking.
+  double _cur_mark_stop_world_time_ms;
+  double _mark_init_start_sec;
+  double _mark_remark_start_sec;
+  double _mark_cleanup_start_sec;
+  double _mark_closure_time_ms;
+
+  void   calculate_young_list_min_length();
+  void   calculate_young_list_target_config();
+  void   calculate_young_list_target_config(size_t rs_lengths);
+  size_t calculate_optimal_so_length(size_t young_list_length);
+
+public:
+
+  G1CollectorPolicy();
+
+  virtual G1CollectorPolicy* as_g1_policy() { return this; }
+
+  virtual CollectorPolicy::Name kind() {
+    return CollectorPolicy::G1CollectorPolicyKind;
+  }
+
+  void check_prediction_validity();
+
+  size_t bytes_in_collection_set() {
+    return _bytes_in_collection_set_before_gc;
+  }
+
+  size_t bytes_in_to_space() {
+    return bytes_in_to_space_during_gc();
+  }
+
+  unsigned calc_gc_alloc_time_stamp() {
+    return _all_pause_times_ms->num() + 1;
+  }
+
+protected:
+
+  // Count the number of bytes used in the CS.
+  void count_CS_bytes_used();
+
+  // Together these do the base cleanup-recording work.  Subclasses might
+  // want to put something between them.
+  void record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
+                                                size_t max_live_bytes);
+  void record_concurrent_mark_cleanup_end_work2();
+
+public:
+
+  virtual void init();
+
+  virtual HeapWord* mem_allocate_work(size_t size,
+                                      bool is_tlab,
+                                      bool* gc_overhead_limit_was_exceeded);
+
+  // This method controls how a collector handles one or more
+  // of its generations being fully allocated.
+  virtual HeapWord* satisfy_failed_allocation(size_t size,
+                                              bool is_tlab);
+
+  BarrierSet::Name barrier_set_name() { return BarrierSet::G1SATBCTLogging; }
+
+  GenRemSet::Name  rem_set_name()     { return GenRemSet::CardTable; }
+
+  // The number of collection pauses so far.
+  long n_pauses() const { return _n_pauses; }
+
+  // Update the heuristic info to record a collection pause of the given
+  // start time, where the given number of bytes were used at the start.
+  // This may involve changing the desired size of a collection set.
+
+  virtual void record_stop_world_start();
+
+  virtual void record_collection_pause_start(double start_time_sec,
+                                             size_t start_used);
+
+  virtual void record_popular_pause_preamble_start();
+  virtual void record_popular_pause_preamble_end();
+
+  // Must currently be called while the world is stopped.
+  virtual void record_concurrent_mark_init_start();
+  virtual void record_concurrent_mark_init_end();
+  void record_concurrent_mark_init_end_pre(double
+                                           mark_init_elapsed_time_ms);
+
+  void record_mark_closure_time(double mark_closure_time_ms);
+
+  virtual void record_concurrent_mark_remark_start();
+  virtual void record_concurrent_mark_remark_end();
+
+  virtual void record_concurrent_mark_cleanup_start();
+  virtual void record_concurrent_mark_cleanup_end(size_t freed_bytes,
+                                                  size_t max_live_bytes);
+  virtual void record_concurrent_mark_cleanup_completed();
+
+  virtual void record_concurrent_pause();
+  virtual void record_concurrent_pause_end();
+
+  virtual void record_collection_pause_end_CH_strong_roots();
+  virtual void record_collection_pause_end_G1_strong_roots();
+
+  virtual void record_collection_pause_end(bool popular, bool abandoned);
+
+  // Record the fact that a full collection occurred.
+  virtual void record_full_collection_start();
+  virtual void record_full_collection_end();
+
+  void record_ext_root_scan_time(int worker_i, double ms) {
+    _par_last_ext_root_scan_times_ms[worker_i] = ms;
+  }
+
+  void record_mark_stack_scan_time(int worker_i, double ms) {
+    _par_last_mark_stack_scan_times_ms[worker_i] = ms;
+  }
+
+  void record_scan_only_time(int worker_i, double ms, int n) {
+    _par_last_scan_only_times_ms[worker_i] = ms;
+    _par_last_scan_only_regions_scanned[worker_i] = (double) n;
+  }
+
+  void record_satb_drain_time(double ms) {
+    _cur_satb_drain_time_ms = ms;
+    _satb_drain_time_set    = true;
+  }
+
+  void record_satb_drain_processed_buffers (int processed_buffers) {
+    _last_satb_drain_processed_buffers = processed_buffers;
+  }
+
+  void record_mod_union_time(double ms) {
+    _all_mod_union_times_ms->add(ms);
+  }
+
+  void record_update_rs_start_time(int thread, double ms) {
+    _par_last_update_rs_start_times_ms[thread] = ms;
+  }
+
+  void record_update_rs_time(int thread, double ms) {
+    _par_last_update_rs_times_ms[thread] = ms;
+  }
+
+  void record_update_rs_processed_buffers (int thread,
+                                           double processed_buffers) {
+    _par_last_update_rs_processed_buffers[thread] = processed_buffers;
+  }
+
+  void record_scan_rs_start_time(int thread, double ms) {
+    _par_last_scan_rs_start_times_ms[thread] = ms;
+  }
+
+  void record_scan_rs_time(int thread, double ms) {
+    _par_last_scan_rs_times_ms[thread] = ms;
+  }
+
+  void record_scan_new_refs_time(int thread, double ms) {
+    _par_last_scan_new_refs_times_ms[thread] = ms;
+  }
+
+  double get_scan_new_refs_time(int thread) {
+    return _par_last_scan_new_refs_times_ms[thread];
+  }
+
+  void reset_obj_copy_time(int thread) {
+    _par_last_obj_copy_times_ms[thread] = 0.0;
+  }
+
+  void reset_obj_copy_time() {
+    reset_obj_copy_time(0);
+  }
+
+  void record_obj_copy_time(int thread, double ms) {
+    _par_last_obj_copy_times_ms[thread] += ms;
+  }
+
+  void record_obj_copy_time(double ms) {
+    record_obj_copy_time(0, ms);
+  }
+
+  void record_termination_time(int thread, double ms) {
+    _par_last_termination_times_ms[thread] = ms;
+  }
+
+  void record_termination_time(double ms) {
+    record_termination_time(0, ms);
+  }
+
+  void record_pause_time(double ms) {
+    _last_pause_time_ms = ms;
+  }
+
+  void record_clear_ct_time(double ms) {
+    _cur_clear_ct_time_ms = ms;
+  }
+
+  void record_par_time(double ms) {
+    _cur_collection_par_time_ms = ms;
+  }
+
+  void record_aux_start_time(int i) {
+    guarantee(i < _aux_num, "should be within range");
+    _cur_aux_start_times_ms[i] = os::elapsedTime() * 1000.0;
+  }
+
+  void record_aux_end_time(int i) {
+    guarantee(i < _aux_num, "should be within range");
+    double ms = os::elapsedTime() * 1000.0 - _cur_aux_start_times_ms[i];
+    _cur_aux_times_set[i] = true;
+    _cur_aux_times_ms[i] += ms;
+  }
+
+  void record_pop_compute_rc_start();
+  void record_pop_compute_rc_end();
+
+  void record_pop_evac_start();
+  void record_pop_evac_end();
+
+  // Record the fact that "bytes" bytes allocated in a region.
+  void record_before_bytes(size_t bytes);
+  void record_after_bytes(size_t bytes);
+
+  // Returns "true" if this is a good time to do a collection pause.
+  // The "word_size" argument, if non-zero, indicates the size of an
+  // allocation request that is prompting this query.
+  virtual bool should_do_collection_pause(size_t word_size) = 0;
+
+  // Choose a new collection set.  Marks the chosen regions as being
+  // "in_collection_set", and links them together.  The head and number of
+  // the collection set are available via access methods.
+  // If "pop_region" is non-NULL, it is a popular region that has already
+  // been added to the collection set.
+  virtual void choose_collection_set(HeapRegion* pop_region = NULL) = 0;
+
+  void clear_collection_set() { _collection_set = NULL; }
+
+  // The head of the list (via "next_in_collection_set()") representing the
+  // current collection set.
+  HeapRegion* collection_set() { return _collection_set; }
+
+  // Sets the collection set to the given single region.
+  virtual void set_single_region_collection_set(HeapRegion* hr);
+
+  // The number of elements in the current collection set.
+  size_t collection_set_size() { return _collection_set_size; }
+
+  // Add "hr" to the CS.
+  void add_to_collection_set(HeapRegion* hr);
+
+  bool should_initiate_conc_mark()      { return _should_initiate_conc_mark; }
+  void set_should_initiate_conc_mark()  { _should_initiate_conc_mark = true; }
+  void unset_should_initiate_conc_mark(){ _should_initiate_conc_mark = false; }
+
+  void checkpoint_conc_overhead();
+
+  // If an expansion would be appropriate, because recent GC overhead had
+  // exceeded the desired limit, return an amount to expand by.
+  virtual size_t expansion_amount();
+
+  // note start of mark thread
+  void note_start_of_mark_thread();
+
+  // The marked bytes of the "r" has changed; reclassify it's desirability
+  // for marking.  Also asserts that "r" is eligible for a CS.
+  virtual void note_change_in_marked_bytes(HeapRegion* r) = 0;
+
+#ifndef PRODUCT
+  // Check any appropriate marked bytes info, asserting false if
+  // something's wrong, else returning "true".
+  virtual bool assertMarkedBytesDataOK() = 0;
+#endif
+
+  // Print tracing information.
+  void print_tracing_info() const;
+
+  // Print stats on young survival ratio
+  void print_yg_surv_rate_info() const;
+
+  void finished_recalculating_age_indexes() {
+    _short_lived_surv_rate_group->finished_recalculating_age_indexes();
+    // do that for any other surv rate groups
+  }
+
+  bool should_add_next_region_to_young_list();
+
+  bool in_young_gc_mode() {
+    return _in_young_gc_mode;
+  }
+  void set_in_young_gc_mode(bool in_young_gc_mode) {
+    _in_young_gc_mode = in_young_gc_mode;
+  }
+
+  bool full_young_gcs() {
+    return _full_young_gcs;
+  }
+  void set_full_young_gcs(bool full_young_gcs) {
+    _full_young_gcs = full_young_gcs;
+  }
+
+  bool adaptive_young_list_length() {
+    return _adaptive_young_list_length;
+  }
+  void set_adaptive_young_list_length(bool adaptive_young_list_length) {
+    _adaptive_young_list_length = adaptive_young_list_length;
+  }
+
+  inline double get_gc_eff_factor() {
+    double ratio = _known_garbage_ratio;
+
+    double square = ratio * ratio;
+    // square = square * square;
+    double ret = square * 9.0 + 1.0;
+#if 0
+    gclog_or_tty->print_cr("ratio = %1.2lf, ret = %1.2lf", ratio, ret);
+#endif // 0
+    guarantee(0.0 <= ret && ret < 10.0, "invariant!");
+    return ret;
+  }
+
+  //
+  // Survivor regions policy.
+  //
+protected:
+
+  // Current tenuring threshold, set to 0 if the collector reaches the
+  // maximum amount of suvivors regions.
+  int _tenuring_threshold;
+
+public:
+
+  inline GCAllocPurpose
+    evacuation_destination(HeapRegion* src_region, int age, size_t word_sz) {
+      if (age < _tenuring_threshold && src_region->is_young()) {
+        return GCAllocForSurvived;
+      } else {
+        return GCAllocForTenured;
+      }
+  }
+
+  inline bool track_object_age(GCAllocPurpose purpose) {
+    return purpose == GCAllocForSurvived;
+  }
+
+  inline GCAllocPurpose alternative_purpose(int purpose) {
+    return GCAllocForTenured;
+  }
+
+  uint max_regions(int purpose);
+
+  // The limit on regions for a particular purpose is reached.
+  void note_alloc_region_limit_reached(int purpose) {
+    if (purpose == GCAllocForSurvived) {
+      _tenuring_threshold = 0;
+    }
+  }
+
+  void note_start_adding_survivor_regions() {
+    _survivor_surv_rate_group->start_adding_regions();
+  }
+
+  void note_stop_adding_survivor_regions() {
+    _survivor_surv_rate_group->stop_adding_regions();
+  }
+};
+
+// This encapsulates a particular strategy for a g1 Collector.
+//
+//      Start a concurrent mark when our heap size is n bytes
+//            greater then our heap size was at the last concurrent
+//            mark.  Where n is a function of the CMSTriggerRatio
+//            and the MinHeapFreeRatio.
+//
+//      Start a g1 collection pause when we have allocated the
+//            average number of bytes currently being freed in
+//            a collection, but only if it is at least one region
+//            full
+//
+//      Resize Heap based on desired
+//      allocation space, where desired allocation space is
+//      a function of survival rate and desired future to size.
+//
+//      Choose collection set by first picking all older regions
+//      which have a survival rate which beats our projected young
+//      survival rate.  Then fill out the number of needed regions
+//      with young regions.
+
+class G1CollectorPolicy_BestRegionsFirst: public G1CollectorPolicy {
+  CollectionSetChooser* _collectionSetChooser;
+  // If the estimated is less then desirable, resize if possible.
+  void expand_if_possible(size_t numRegions);
+
+  virtual void choose_collection_set(HeapRegion* pop_region = NULL);
+  virtual void record_collection_pause_start(double start_time_sec,
+                                             size_t start_used);
+  virtual void record_concurrent_mark_cleanup_end(size_t freed_bytes,
+                                                  size_t max_live_bytes);
+  virtual void record_full_collection_end();
+
+public:
+  G1CollectorPolicy_BestRegionsFirst() {
+    _collectionSetChooser = new CollectionSetChooser();
+  }
+  void record_collection_pause_end(bool popular, bool abandoned);
+  bool should_do_collection_pause(size_t word_size);
+  virtual void set_single_region_collection_set(HeapRegion* hr);
+  // This is not needed any more, after the CSet choosing code was
+  // changed to use the pause prediction work. But let's leave the
+  // hook in just in case.
+  void note_change_in_marked_bytes(HeapRegion* r) { }
+#ifndef PRODUCT
+  bool assertMarkedBytesDataOK();
+#endif
+};
+
+// This should move to some place more general...
+
+// If we have "n" measurements, and we've kept track of their "sum" and the
+// "sum_of_squares" of the measurements, this returns the variance of the
+// sequence.
+inline double variance(int n, double sum_of_squares, double sum) {
+  double n_d = (double)n;
+  double avg = sum/n_d;
+  return (sum_of_squares - 2.0 * avg * sum + n_d * avg * avg) / n_d;
+}
+
+// Local Variables: ***
+// c-indentation-style: gnu ***
+// End: ***