1 /*
   2  * Copyright (c) 2001, 2015, 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.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc/g1/g1CollectedHeap.inline.hpp"
  27 #include "gc/g1/g1Predictions.hpp"
  28 #include "gc/g1/heapRegion.hpp"
  29 #include "gc/g1/survRateGroup.hpp"
  30 #include "logging/log.hpp"
  31 #include "memory/allocation.hpp"
  32 
  33 SurvRateGroup::SurvRateGroup() :
  34   _stats_arrays_length(0),
  35   _accum_surv_rate_pred(NULL),
  36   _last_pred(0.0),
  37   _surv_rate_pred(NULL),
  38   _all_regions_allocated(0),
  39   _region_num(0),
  40   _setup_seq_num(0)
  41 {
  42   reset();
  43   start_adding_regions();
  44 }
  45 
  46 void SurvRateGroup::reset() {
  47   _all_regions_allocated = 0;
  48   _setup_seq_num         = 0;
  49   _last_pred             = 0.0;
  50   // the following will set up the arrays with length 1
  51   _region_num            = 1;
  52 
  53   // The call to stop_adding_regions() will use "new" to refill
  54   // the _surv_rate_pred array, so we need to make sure to call
  55   // "delete".
  56   for (size_t i = 0; i < _stats_arrays_length; ++i) {
  57     delete _surv_rate_pred[i];
  58   }
  59   _stats_arrays_length = 0;
  60 
  61   stop_adding_regions();
  62 
  63   // Seed initial _surv_rate_pred and _accum_surv_rate_pred values
  64   guarantee( _stats_arrays_length == 1, "invariant" );
  65   guarantee( _surv_rate_pred[0] != NULL, "invariant" );
  66   const double initial_surv_rate = 0.4;
  67   _surv_rate_pred[0]->add(initial_surv_rate);
  68   _last_pred = _accum_surv_rate_pred[0] = initial_surv_rate;
  69 
  70   _region_num = 0;
  71 }
  72 
  73 void SurvRateGroup::start_adding_regions() {
  74   _setup_seq_num   = _stats_arrays_length;
  75   _region_num      = 0;
  76 }
  77 
  78 void SurvRateGroup::stop_adding_regions() {
  79   if (_region_num > _stats_arrays_length) {
  80     _accum_surv_rate_pred = REALLOC_C_HEAP_ARRAY(double, _accum_surv_rate_pred, _region_num, mtGC);
  81     _surv_rate_pred = REALLOC_C_HEAP_ARRAY(TruncatedSeq*, _surv_rate_pred, _region_num, mtGC);
  82 
  83     for (size_t i = _stats_arrays_length; i < _region_num; ++i) {
  84       _surv_rate_pred[i] = new TruncatedSeq(10);
  85     }
  86 
  87     _stats_arrays_length = _region_num;
  88   }
  89 }
  90 
  91 void SurvRateGroup::record_surviving_words(int age_in_group, size_t surv_words) {
  92   guarantee( 0 <= age_in_group && (size_t) age_in_group < _region_num,
  93              "pre-condition" );
  94 
  95   double surv_rate = (double) surv_words / (double) HeapRegion::GrainWords;
  96   _surv_rate_pred[age_in_group]->add(surv_rate);
  97 }
  98 
  99 void SurvRateGroup::all_surviving_words_recorded(const G1Predictions& predictor, bool update_predictors) {
 100   if (update_predictors) {
 101     fill_in_last_surv_rates();
 102   }
 103   finalize_predictions(predictor);
 104 }
 105 
 106 void SurvRateGroup::fill_in_last_surv_rates() {
 107   if (_region_num > 0) { // conservative
 108     double surv_rate = _surv_rate_pred[_region_num-1]->last();
 109     for (size_t i = _region_num; i < _stats_arrays_length; ++i) {
 110       _surv_rate_pred[i]->add(surv_rate);
 111     }
 112   }
 113 }
 114 
 115 void SurvRateGroup::finalize_predictions(const G1Predictions& predictor) {
 116   double accum = 0.0;
 117   double pred = 0.0;
 118   for (size_t i = 0; i < _stats_arrays_length; ++i) {
 119     pred = predictor.get_new_prediction(_surv_rate_pred[i]);
 120     if (pred > 1.0) pred = 1.0;
 121     accum += pred;
 122     _accum_surv_rate_pred[i] = accum;
 123   }
 124   _last_pred = pred;
 125 }