1 /*
   2  * Copyright (c) 2016, 2020, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  24 
  25 #ifndef SHARE_GC_G1_G1ANALYTICS_HPP
  26 #define SHARE_GC_G1_G1ANALYTICS_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "utilities/globalDefinitions.hpp"
  30 
  31 class TruncatedSeq;
  32 class G1Predictions;
  33 
  34 class G1Analytics: public CHeapObj<mtGC> {
  35   const static int TruncatedSeqLength = 10;
  36   const static int NumPrevPausesForHeuristics = 10;
  37   const G1Predictions* _predictor;
  38 
  39   // These exclude marking times.
  40   TruncatedSeq* _recent_gc_times_ms;
  41 
  42   TruncatedSeq* _concurrent_mark_remark_times_ms;
  43   TruncatedSeq* _concurrent_mark_cleanup_times_ms;
  44 
  45   TruncatedSeq* _alloc_rate_ms_seq;
  46   double        _prev_collection_pause_end_ms;
  47 
  48   TruncatedSeq* _rs_length_diff_seq;
  49   TruncatedSeq* _concurrent_refine_rate_ms_seq;
  50   TruncatedSeq* _dirtied_cards_rate_ms_seq;
  51   // The ratio between the number of merged cards and actually scanned cards, for
  52   // young-only and mixed gcs.
  53   TruncatedSeq* _young_card_merge_to_scan_ratio_seq;
  54   TruncatedSeq* _mixed_card_merge_to_scan_ratio_seq;
  55 
  56   // The cost to scan a card during young-only and mixed gcs in ms.
  57   TruncatedSeq* _young_cost_per_card_scan_ms_seq;
  58   TruncatedSeq* _mixed_cost_per_card_scan_ms_seq;
  59 
  60   // The cost to merge a card during young-only and mixed gcs in ms.
  61   TruncatedSeq* _young_cost_per_card_merge_ms_seq;
  62   TruncatedSeq* _mixed_cost_per_card_merge_ms_seq;
  63 
  64   // The cost to copy a byte in ms.
  65   TruncatedSeq* _copy_cost_per_byte_ms_seq;
  66   TruncatedSeq* _constant_other_time_ms_seq;
  67   TruncatedSeq* _young_other_cost_per_region_ms_seq;
  68   TruncatedSeq* _non_young_other_cost_per_region_ms_seq;
  69 
  70   TruncatedSeq* _pending_cards_seq;
  71   TruncatedSeq* _rs_length_seq;
  72 
  73   TruncatedSeq* _cost_per_byte_ms_during_cm_seq;
  74 
  75   // Statistics kept per GC stoppage, pause or full.
  76   TruncatedSeq* _recent_prev_end_times_for_all_gcs_sec;
  77 
  78   // Cached values for long and short term pause time ratios. See
  79   // compute_pause_time_ratios() for how they are computed.
  80   double _long_term_pause_time_ratio;
  81   double _short_term_pause_time_ratio;
  82 
  83   // Returns whether the sequence have enough samples to get a "good" prediction.
  84   // The constant used is random but "small".
  85   bool enough_samples_available(TruncatedSeq const* seq) const;
  86 
  87   double predict_in_unit_interval(TruncatedSeq const* seq) const;
  88   size_t predict_size(TruncatedSeq const* seq) const;
  89   double predict_zero_bounded(TruncatedSeq const* seq) const;
  90 
  91 public:
  92   G1Analytics(const G1Predictions* predictor);
  93 
  94   double prev_collection_pause_end_ms() const {
  95     return _prev_collection_pause_end_ms;
  96   }
  97 
  98   double long_term_pause_time_ratio() const {
  99     return _long_term_pause_time_ratio;
 100   }
 101 
 102   double short_term_pause_time_ratio() const {
 103     return _short_term_pause_time_ratio;
 104   }
 105 
 106   uint number_of_recorded_pause_times() const {
 107     return NumPrevPausesForHeuristics;
 108   }
 109 
 110   void append_prev_collection_pause_end_ms(double ms) {
 111     _prev_collection_pause_end_ms += ms;
 112   }
 113 
 114   void report_concurrent_mark_remark_times_ms(double ms);
 115   void report_concurrent_mark_cleanup_times_ms(double ms);
 116   void report_alloc_rate_ms(double alloc_rate);
 117   void report_concurrent_refine_rate_ms(double cards_per_ms);
 118   void report_dirtied_cards_rate_ms(double cards_per_ms);
 119   void report_cost_per_card_scan_ms(double cost_per_remset_card_ms, bool for_young_gc);
 120   void report_cost_per_card_merge_ms(double cost_per_card_ms, bool for_young_gc);
 121   void report_card_merge_to_scan_ratio(double cards_per_entry_ratio, bool for_young_gc);
 122   void report_rs_length_diff(double rs_length_diff);
 123   void report_cost_per_byte_ms(double cost_per_byte_ms, bool mark_or_rebuild_in_progress);
 124   void report_young_other_cost_per_region_ms(double other_cost_per_region_ms);
 125   void report_non_young_other_cost_per_region_ms(double other_cost_per_region_ms);
 126   void report_constant_other_time_ms(double constant_other_time_ms);
 127   void report_pending_cards(double pending_cards);
 128   void report_rs_length(double rs_length);
 129 
 130   double predict_alloc_rate_ms() const;
 131   int num_alloc_rate_ms() const;
 132 
 133   double predict_concurrent_refine_rate_ms() const;
 134   double predict_dirtied_cards_rate_ms() const;
 135   double predict_young_card_merge_to_scan_ratio() const;
 136 
 137   double predict_mixed_card_merge_to_scan_ratio() const;
 138 
 139   size_t predict_scan_card_num(size_t rs_length, bool for_young_gc) const;
 140 
 141   double predict_card_merge_time_ms(size_t card_num, bool for_young_gc) const;
 142   double predict_card_scan_time_ms(size_t card_num, bool for_young_gc) const;
 143 
 144   double predict_object_copy_time_ms_during_cm(size_t bytes_to_copy) const;
 145 
 146   double predict_object_copy_time_ms(size_t bytes_to_copy, bool during_concurrent_mark) const;
 147 
 148   double predict_constant_other_time_ms() const;
 149 
 150   double predict_young_other_time_ms(size_t young_num) const;
 151 
 152   double predict_non_young_other_time_ms(size_t non_young_num) const;
 153 
 154   double predict_remark_time_ms() const;
 155 
 156   double predict_cleanup_time_ms() const;
 157 
 158   size_t predict_rs_length() const;
 159   size_t predict_pending_cards() const;
 160 
 161   // Add a new GC of the given duration and end time to the record.
 162   void update_recent_gc_times(double end_time_sec, double elapsed_ms);
 163   void compute_pause_time_ratio(double interval_ms, double pause_time_ms);
 164 
 165   double last_known_gc_end_time_sec() const;
 166 };
 167 
 168 #endif // SHARE_GC_G1_G1ANALYTICS_HPP