view src/share/vm/gc_implementation/g1/survRateGroup.hpp @ 453:c96030fff130

6684579: SoftReference processing can be made more efficient Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not. Reviewed-by: jmasa
author ysr
date Thu, 20 Nov 2008 16:56:09 -0800
parents 37f87013dfd8
children 58054a18d735
line wrap: on
line source

/*
 * 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.
 *
 */

class G1CollectorPolicy;

class SurvRateGroup : public CHeapObj {
private:
  G1CollectorPolicy* _g1p;
  const char* _name;

  size_t  _array_length;
  double* _surv_rate;
  double* _accum_surv_rate_pred;
  double  _last_pred;
  double  _accum_surv_rate;
  TruncatedSeq** _surv_rate_pred;
  NumberSeq**    _summary_surv_rates;
  size_t         _summary_surv_rates_len;
  size_t         _summary_surv_rates_max_len;

  int _all_regions_allocated;
  size_t _curr_length;
  size_t _scan_only_prefix;
  size_t _setup_seq_num;

public:
  SurvRateGroup(G1CollectorPolicy* g1p,
                const char* name,
                size_t summary_surv_rates_len);
  void start_adding_regions();
  void stop_adding_regions();
  void record_scan_only_prefix(size_t scan_only_prefix);
  void record_surviving_words(int age_in_group, size_t surv_words);
  void all_surviving_words_recorded(bool propagate);
  const char* name() { return _name; }

  size_t region_num() { return _curr_length; }
  size_t scan_only_length() { return _scan_only_prefix; }
  double accum_surv_rate_pred(int age) {
    assert(age >= 0, "must be");
    if ((size_t)age < _array_length)
      return _accum_surv_rate_pred[age];
    else {
      double diff = (double) (age - _array_length + 1);
      return _accum_surv_rate_pred[_array_length-1] + diff * _last_pred;
    }
  }

  double accum_surv_rate(size_t adjustment);

  TruncatedSeq* get_seq(size_t age) {
    guarantee( 0 <= age, "pre-condition" );
    if (age >= _setup_seq_num) {
      guarantee( _setup_seq_num > 0, "invariant" );
      age = _setup_seq_num-1;
    }
    TruncatedSeq* seq = _surv_rate_pred[age];
    guarantee( seq != NULL, "invariant" );
    return seq;
  }

  int next_age_index();
  int age_in_group(int age_index) {
    int ret = (int) (_all_regions_allocated -  age_index);
    assert( ret >= 0, "invariant" );
    return ret;
  }
  int recalculate_age_index(int age_index) {
    int new_age_index = (int) _scan_only_prefix - age_in_group(age_index);
    guarantee( new_age_index >= 0, "invariant" );
    return new_age_index;
  }
  void finished_recalculating_age_indexes() {
    _all_regions_allocated = (int) _scan_only_prefix;
  }

#ifndef PRODUCT
  void print();
  void print_surv_rate_summary();
#endif // PRODUCT
};