/*

 * Copyright (c) 2001, 2015, 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.

 *

 */

#include "precompiled.hpp"

#include "gc/g1/g1CollectedHeap.inline.hpp"

#include "gc/g1/g1Predictions.hpp"

#include "gc/g1/heapRegion.hpp"

#include "gc/g1/survRateGroup.hpp"

#include "logging/log.hpp"

#include "memory/allocation.hpp"

SurvRateGroup::SurvRateGroup() :

  _stats_arrays_length(0),

  _accum_surv_rate_pred(NULL),

  _last_pred(0.0),

  _surv_rate_pred(NULL),

  _all_regions_allocated(0),

  _region_num(0),

  _setup_seq_num(0)

{

  reset();

  start_adding_regions();

}

void SurvRateGroup::reset() {

  _all_regions_allocated = 0;

  _setup_seq_num         = 0;

  _last_pred             = 0.0;

  // the following will set up the arrays with length 1

  _region_num            = 1;

  // The call to stop_adding_regions() will use "new" to refill

  // the _surv_rate_pred array, so we need to make sure to call

  // "delete".

  for (size_t i = 0; i < _stats_arrays_length; ++i) {

    delete _surv_rate_pred[i];

  }

  _stats_arrays_length = 0;

  stop_adding_regions();

  // Seed initial _surv_rate_pred and _accum_surv_rate_pred values

  guarantee( _stats_arrays_length == 1, "invariant" );

  guarantee( _surv_rate_pred[0] != NULL, "invariant" );

  const double initial_surv_rate = 0.4;

  _surv_rate_pred[0]->add(initial_surv_rate);

  _last_pred = _accum_surv_rate_pred[0] = initial_surv_rate;

  _region_num = 0;

}

void SurvRateGroup::start_adding_regions() {

  _setup_seq_num   = _stats_arrays_length;

  _region_num      = 0;

}

void SurvRateGroup::stop_adding_regions() {

  if (_region_num > _stats_arrays_length) {

    _accum_surv_rate_pred = REALLOC_C_HEAP_ARRAY(double, _accum_surv_rate_pred, _region_num, mtGC);

    _surv_rate_pred = REALLOC_C_HEAP_ARRAY(TruncatedSeq*, _surv_rate_pred, _region_num, mtGC);

    for (size_t i = _stats_arrays_length; i < _region_num; ++i) {

      _surv_rate_pred[i] = new TruncatedSeq(10);

    }

    _stats_arrays_length = _region_num;

  }

}

void SurvRateGroup::record_surviving_words(int age_in_group, size_t surv_words) {

  guarantee( 0 <= age_in_group && (size_t) age_in_group < _region_num,

             "pre-condition" );

  double surv_rate = (double) surv_words / (double) HeapRegion::GrainWords;

  _surv_rate_pred[age_in_group]->add(surv_rate);

}

void SurvRateGroup::all_surviving_words_recorded(const G1Predictions& predictor, bool update_predictors) {

  if (update_predictors) {

    fill_in_last_surv_rates();

  }

  finalize_predictions(predictor);

}

void SurvRateGroup::fill_in_last_surv_rates() {

  if (_region_num > 0) { // conservative

    double surv_rate = _surv_rate_pred[_region_num-1]->last();

    for (size_t i = _region_num; i < _stats_arrays_length; ++i) {

      _surv_rate_pred[i]->add(surv_rate);

    }

  }

}

void SurvRateGroup::finalize_predictions(const G1Predictions& predictor) {

  double accum = 0.0;

  double pred = 0.0;

  for (size_t i = 0; i < _stats_arrays_length; ++i) {

    pred = predictor.get_new_prediction(_surv_rate_pred[i]);

    if (pred > 1.0) pred = 1.0;

    accum += pred;

    _accum_surv_rate_pred[i] = accum;

  }

  _last_pred = pred;

}