view src/share/vm/gc_implementation/g1/survRateGroup.cpp @ 2034:7e37af9d69ef

7011379: G1: overly long concurrent marking cycles Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads. Reviewed-by: johnc, ysr
author tonyp
date Wed, 19 Jan 2011 09:35:17 -0500
parents c18cbe5936b8
children 2c0751569716
line wrap: on
line source
/*
 * Copyright (c) 2001, 2010, 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_implementation/g1/g1CollectedHeap.inline.hpp"
#include "gc_implementation/g1/g1CollectorPolicy.hpp"
#include "gc_implementation/g1/heapRegion.hpp"
#include "gc_implementation/g1/survRateGroup.hpp"
#include "memory/allocation.hpp"

SurvRateGroup::SurvRateGroup(G1CollectorPolicy* g1p,
                             const char* name,
                             size_t summary_surv_rates_len) :
    _g1p(g1p), _name(name),
    _summary_surv_rates_len(summary_surv_rates_len),
    _summary_surv_rates_max_len(0),
    _summary_surv_rates(NULL),
    _surv_rate(NULL),
    _accum_surv_rate_pred(NULL),
    _surv_rate_pred(NULL)
{
  reset();
  if (summary_surv_rates_len > 0) {
    size_t length = summary_surv_rates_len;
      _summary_surv_rates = NEW_C_HEAP_ARRAY(NumberSeq*, length);
    if (_summary_surv_rates == NULL) {
      vm_exit_out_of_memory(sizeof(NumberSeq*) * length,
                            "Not enough space for surv rate summary");
    }
    for (size_t i = 0; i < length; ++i)
      _summary_surv_rates[i] = new NumberSeq();
  }

  start_adding_regions();
}


void SurvRateGroup::reset()
{
  _all_regions_allocated = 0;
  _setup_seq_num         = 0;
  _stats_arrays_length   = 0;
  _accum_surv_rate       = 0.0;
  _last_pred             = 0.0;
  // the following will set up the arrays with length 1
  _region_num            = 1;
  stop_adding_regions();
  guarantee( _stats_arrays_length == 1, "invariant" );
  guarantee( _surv_rate_pred[0] != NULL, "invariant" );
  _surv_rate_pred[0]->add(0.4);
  all_surviving_words_recorded(false);
  _region_num = 0;
}


void
SurvRateGroup::start_adding_regions() {
  _setup_seq_num   = _stats_arrays_length;
  _region_num      = 0;
  _accum_surv_rate = 0.0;

#if 0
  gclog_or_tty->print_cr("[%s] start adding regions, seq num %d, length %d",
                         _name, _setup_seq_num, _region_num);
#endif // 0
}

void
SurvRateGroup::stop_adding_regions() {

#if 0
  gclog_or_tty->print_cr("[%s] stop adding regions, length %d", _name, _region_num);
#endif // 0

  if (_region_num > _stats_arrays_length) {
    double* old_surv_rate = _surv_rate;
    double* old_accum_surv_rate_pred = _accum_surv_rate_pred;
    TruncatedSeq** old_surv_rate_pred = _surv_rate_pred;

    _surv_rate = NEW_C_HEAP_ARRAY(double, _region_num);
    if (_surv_rate == NULL) {
      vm_exit_out_of_memory(sizeof(double) * _region_num,
                            "Not enough space for surv rate array.");
    }
    _accum_surv_rate_pred = NEW_C_HEAP_ARRAY(double, _region_num);
    if (_accum_surv_rate_pred == NULL) {
      vm_exit_out_of_memory(sizeof(double) * _region_num,
                         "Not enough space for accum surv rate pred array.");
    }
    _surv_rate_pred = NEW_C_HEAP_ARRAY(TruncatedSeq*, _region_num);
    if (_surv_rate == NULL) {
      vm_exit_out_of_memory(sizeof(TruncatedSeq*) * _region_num,
                            "Not enough space for surv rate pred array.");
    }

    for (size_t i = 0; i < _stats_arrays_length; ++i)
      _surv_rate_pred[i] = old_surv_rate_pred[i];

#if 0
    gclog_or_tty->print_cr("[%s] stop adding regions, new seqs %d to %d",
                  _name, _array_length, _region_num - 1);
#endif // 0

    for (size_t i = _stats_arrays_length; i < _region_num; ++i) {
      _surv_rate_pred[i] = new TruncatedSeq(10);
      // _surv_rate_pred[i]->add(last_pred);
    }

    _stats_arrays_length = _region_num;

    if (old_surv_rate != NULL)
      FREE_C_HEAP_ARRAY(double, old_surv_rate);
    if (old_accum_surv_rate_pred != NULL)
      FREE_C_HEAP_ARRAY(double, old_accum_surv_rate_pred);
    if (old_surv_rate_pred != NULL)
      FREE_C_HEAP_ARRAY(NumberSeq*, old_surv_rate_pred);
  }

  for (size_t i = 0; i < _stats_arrays_length; ++i)
    _surv_rate[i] = 0.0;
}

double
SurvRateGroup::accum_surv_rate(size_t adjustment) {
  // we might relax this one in the future...
  guarantee( adjustment == 0 || adjustment == 1, "pre-condition" );

  double ret = _accum_surv_rate;
  if (adjustment > 0) {
    TruncatedSeq* seq = get_seq(_region_num+1);
    double surv_rate = _g1p->get_new_prediction(seq);
    ret += surv_rate;
  }

  return ret;
}

int
SurvRateGroup::next_age_index() {
  TruncatedSeq* seq = get_seq(_region_num);
  double surv_rate = _g1p->get_new_prediction(seq);
  _accum_surv_rate += surv_rate;

  ++_region_num;
  return (int) ++_all_regions_allocated;
}

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" );
  guarantee( _surv_rate[age_in_group] <= 0.00001,
             "should only update each slot once" );

  double surv_rate = (double) surv_words / (double) HeapRegion::GrainWords;
  _surv_rate[age_in_group] = surv_rate;
  _surv_rate_pred[age_in_group]->add(surv_rate);
  if ((size_t)age_in_group < _summary_surv_rates_len) {
    _summary_surv_rates[age_in_group]->add(surv_rate);
    if ((size_t)(age_in_group+1) > _summary_surv_rates_max_len)
      _summary_surv_rates_max_len = age_in_group+1;
  }
}

void
SurvRateGroup::all_surviving_words_recorded(bool propagate) {
  if (propagate && _region_num > 0) { // conservative
    double surv_rate = _surv_rate_pred[_region_num-1]->last();

#if 0
    gclog_or_tty->print_cr("propagating %1.2lf from %d to %d",
                  surv_rate, _curr_length, _array_length - 1);
#endif // 0

    for (size_t i = _region_num; i < _stats_arrays_length; ++i) {
      guarantee( _surv_rate[i] <= 0.00001,
                 "the slot should not have been updated" );
      _surv_rate_pred[i]->add(surv_rate);
    }
  }

  double accum = 0.0;
  double pred = 0.0;
  for (size_t i = 0; i < _stats_arrays_length; ++i) {
    pred = _g1p->get_new_prediction(_surv_rate_pred[i]);
    if (pred > 1.0) pred = 1.0;
    accum += pred;
    _accum_surv_rate_pred[i] = accum;
    // gclog_or_tty->print_cr("age %3d, accum %10.2lf", i, accum);
  }
  _last_pred = pred;
}

#ifndef PRODUCT
void
SurvRateGroup::print() {
  gclog_or_tty->print_cr("Surv Rate Group: %s (%d entries)",
                _name, _region_num);
  for (size_t i = 0; i < _region_num; ++i) {
    gclog_or_tty->print_cr("    age %4d   surv rate %6.2lf %%   pred %6.2lf %%",
                  i, _surv_rate[i] * 100.0,
                  _g1p->get_new_prediction(_surv_rate_pred[i]) * 100.0);
  }
}

void
SurvRateGroup::print_surv_rate_summary() {
  size_t length = _summary_surv_rates_max_len;
  if (length == 0)
    return;

  gclog_or_tty->print_cr("");
  gclog_or_tty->print_cr("%s Rate Summary (for up to age %d)", _name, length-1);
  gclog_or_tty->print_cr("      age range     survival rate (avg)      samples (avg)");
  gclog_or_tty->print_cr("  ---------------------------------------------------------");

  size_t index = 0;
  size_t limit = MIN2((int) length, 10);
  while (index < limit) {
    gclog_or_tty->print_cr("           %4d                 %6.2lf%%             %6.2lf",
                  index, _summary_surv_rates[index]->avg() * 100.0,
                  (double) _summary_surv_rates[index]->num());
    ++index;
  }

  gclog_or_tty->print_cr("  ---------------------------------------------------------");

  int num = 0;
  double sum = 0.0;
  int samples = 0;
  while (index < length) {
    ++num;
    sum += _summary_surv_rates[index]->avg() * 100.0;
    samples += _summary_surv_rates[index]->num();
    ++index;

    if (index == length || num % 10 == 0) {
      gclog_or_tty->print_cr("   %4d .. %4d                 %6.2lf%%             %6.2lf",
                    (index-1) / 10 * 10, index-1, sum / (double) num,
                    (double) samples / (double) num);
      sum = 0.0;
      num = 0;
      samples = 0;
    }
  }

  gclog_or_tty->print_cr("  ---------------------------------------------------------");
}
#endif // PRODUCT