src/share/vm/gc_implementation/g1/survRateGroup.cpp

Tue, 10 Jan 2012 18:58:13 -0500

author
tonyp
date
Tue, 10 Jan 2012 18:58:13 -0500
changeset 3416
2ace1c4ee8da
parent 2314
f95d63e2154a
child 3641
2c0751569716
permissions
-rw-r--r--

6888336: G1: avoid explicitly marking and pushing objects in survivor spaces
Summary: This change simplifies the interaction between GC and concurrent marking. By disabling survivor spaces during the initial-mark pause we don't need to propagate marks of objects we copy during each GC (since we never need to copy an explicitly marked object).
Reviewed-by: johnc, brutisso

     1 /*
     2  * Copyright (c) 2001, 2010, 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  */
    25 #include "precompiled.hpp"
    26 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
    27 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
    28 #include "gc_implementation/g1/heapRegion.hpp"
    29 #include "gc_implementation/g1/survRateGroup.hpp"
    30 #include "memory/allocation.hpp"
    32 SurvRateGroup::SurvRateGroup(G1CollectorPolicy* g1p,
    33                              const char* name,
    34                              size_t summary_surv_rates_len) :
    35     _g1p(g1p), _name(name),
    36     _summary_surv_rates_len(summary_surv_rates_len),
    37     _summary_surv_rates_max_len(0),
    38     _summary_surv_rates(NULL),
    39     _surv_rate(NULL),
    40     _accum_surv_rate_pred(NULL),
    41     _surv_rate_pred(NULL)
    42 {
    43   reset();
    44   if (summary_surv_rates_len > 0) {
    45     size_t length = summary_surv_rates_len;
    46       _summary_surv_rates = NEW_C_HEAP_ARRAY(NumberSeq*, length);
    47     if (_summary_surv_rates == NULL) {
    48       vm_exit_out_of_memory(sizeof(NumberSeq*) * length,
    49                             "Not enough space for surv rate summary");
    50     }
    51     for (size_t i = 0; i < length; ++i)
    52       _summary_surv_rates[i] = new NumberSeq();
    53   }
    55   start_adding_regions();
    56 }
    59 void SurvRateGroup::reset()
    60 {
    61   _all_regions_allocated = 0;
    62   _setup_seq_num         = 0;
    63   _stats_arrays_length   = 0;
    64   _accum_surv_rate       = 0.0;
    65   _last_pred             = 0.0;
    66   // the following will set up the arrays with length 1
    67   _region_num            = 1;
    68   stop_adding_regions();
    69   guarantee( _stats_arrays_length == 1, "invariant" );
    70   guarantee( _surv_rate_pred[0] != NULL, "invariant" );
    71   _surv_rate_pred[0]->add(0.4);
    72   all_surviving_words_recorded(false);
    73   _region_num = 0;
    74 }
    77 void
    78 SurvRateGroup::start_adding_regions() {
    79   _setup_seq_num   = _stats_arrays_length;
    80   _region_num      = 0;
    81   _accum_surv_rate = 0.0;
    83 #if 0
    84   gclog_or_tty->print_cr("[%s] start adding regions, seq num %d, length %d",
    85                          _name, _setup_seq_num, _region_num);
    86 #endif // 0
    87 }
    89 void
    90 SurvRateGroup::stop_adding_regions() {
    92 #if 0
    93   gclog_or_tty->print_cr("[%s] stop adding regions, length %d", _name, _region_num);
    94 #endif // 0
    96   if (_region_num > _stats_arrays_length) {
    97     double* old_surv_rate = _surv_rate;
    98     double* old_accum_surv_rate_pred = _accum_surv_rate_pred;
    99     TruncatedSeq** old_surv_rate_pred = _surv_rate_pred;
   101     _surv_rate = NEW_C_HEAP_ARRAY(double, _region_num);
   102     if (_surv_rate == NULL) {
   103       vm_exit_out_of_memory(sizeof(double) * _region_num,
   104                             "Not enough space for surv rate array.");
   105     }
   106     _accum_surv_rate_pred = NEW_C_HEAP_ARRAY(double, _region_num);
   107     if (_accum_surv_rate_pred == NULL) {
   108       vm_exit_out_of_memory(sizeof(double) * _region_num,
   109                          "Not enough space for accum surv rate pred array.");
   110     }
   111     _surv_rate_pred = NEW_C_HEAP_ARRAY(TruncatedSeq*, _region_num);
   112     if (_surv_rate == NULL) {
   113       vm_exit_out_of_memory(sizeof(TruncatedSeq*) * _region_num,
   114                             "Not enough space for surv rate pred array.");
   115     }
   117     for (size_t i = 0; i < _stats_arrays_length; ++i)
   118       _surv_rate_pred[i] = old_surv_rate_pred[i];
   120 #if 0
   121     gclog_or_tty->print_cr("[%s] stop adding regions, new seqs %d to %d",
   122                   _name, _array_length, _region_num - 1);
   123 #endif // 0
   125     for (size_t i = _stats_arrays_length; i < _region_num; ++i) {
   126       _surv_rate_pred[i] = new TruncatedSeq(10);
   127       // _surv_rate_pred[i]->add(last_pred);
   128     }
   130     _stats_arrays_length = _region_num;
   132     if (old_surv_rate != NULL)
   133       FREE_C_HEAP_ARRAY(double, old_surv_rate);
   134     if (old_accum_surv_rate_pred != NULL)
   135       FREE_C_HEAP_ARRAY(double, old_accum_surv_rate_pred);
   136     if (old_surv_rate_pred != NULL)
   137       FREE_C_HEAP_ARRAY(NumberSeq*, old_surv_rate_pred);
   138   }
   140   for (size_t i = 0; i < _stats_arrays_length; ++i)
   141     _surv_rate[i] = 0.0;
   142 }
   144 double
   145 SurvRateGroup::accum_surv_rate(size_t adjustment) {
   146   // we might relax this one in the future...
   147   guarantee( adjustment == 0 || adjustment == 1, "pre-condition" );
   149   double ret = _accum_surv_rate;
   150   if (adjustment > 0) {
   151     TruncatedSeq* seq = get_seq(_region_num+1);
   152     double surv_rate = _g1p->get_new_prediction(seq);
   153     ret += surv_rate;
   154   }
   156   return ret;
   157 }
   159 int
   160 SurvRateGroup::next_age_index() {
   161   TruncatedSeq* seq = get_seq(_region_num);
   162   double surv_rate = _g1p->get_new_prediction(seq);
   163   _accum_surv_rate += surv_rate;
   165   ++_region_num;
   166   return (int) ++_all_regions_allocated;
   167 }
   169 void
   170 SurvRateGroup::record_surviving_words(int age_in_group, size_t surv_words) {
   171   guarantee( 0 <= age_in_group && (size_t) age_in_group < _region_num,
   172              "pre-condition" );
   173   guarantee( _surv_rate[age_in_group] <= 0.00001,
   174              "should only update each slot once" );
   176   double surv_rate = (double) surv_words / (double) HeapRegion::GrainWords;
   177   _surv_rate[age_in_group] = surv_rate;
   178   _surv_rate_pred[age_in_group]->add(surv_rate);
   179   if ((size_t)age_in_group < _summary_surv_rates_len) {
   180     _summary_surv_rates[age_in_group]->add(surv_rate);
   181     if ((size_t)(age_in_group+1) > _summary_surv_rates_max_len)
   182       _summary_surv_rates_max_len = age_in_group+1;
   183   }
   184 }
   186 void
   187 SurvRateGroup::all_surviving_words_recorded(bool propagate) {
   188   if (propagate && _region_num > 0) { // conservative
   189     double surv_rate = _surv_rate_pred[_region_num-1]->last();
   191 #if 0
   192     gclog_or_tty->print_cr("propagating %1.2lf from %d to %d",
   193                   surv_rate, _curr_length, _array_length - 1);
   194 #endif // 0
   196     for (size_t i = _region_num; i < _stats_arrays_length; ++i) {
   197       guarantee( _surv_rate[i] <= 0.00001,
   198                  "the slot should not have been updated" );
   199       _surv_rate_pred[i]->add(surv_rate);
   200     }
   201   }
   203   double accum = 0.0;
   204   double pred = 0.0;
   205   for (size_t i = 0; i < _stats_arrays_length; ++i) {
   206     pred = _g1p->get_new_prediction(_surv_rate_pred[i]);
   207     if (pred > 1.0) pred = 1.0;
   208     accum += pred;
   209     _accum_surv_rate_pred[i] = accum;
   210     // gclog_or_tty->print_cr("age %3d, accum %10.2lf", i, accum);
   211   }
   212   _last_pred = pred;
   213 }
   215 #ifndef PRODUCT
   216 void
   217 SurvRateGroup::print() {
   218   gclog_or_tty->print_cr("Surv Rate Group: %s (%d entries)",
   219                 _name, _region_num);
   220   for (size_t i = 0; i < _region_num; ++i) {
   221     gclog_or_tty->print_cr("    age %4d   surv rate %6.2lf %%   pred %6.2lf %%",
   222                   i, _surv_rate[i] * 100.0,
   223                   _g1p->get_new_prediction(_surv_rate_pred[i]) * 100.0);
   224   }
   225 }
   227 void
   228 SurvRateGroup::print_surv_rate_summary() {
   229   size_t length = _summary_surv_rates_max_len;
   230   if (length == 0)
   231     return;
   233   gclog_or_tty->print_cr("");
   234   gclog_or_tty->print_cr("%s Rate Summary (for up to age %d)", _name, length-1);
   235   gclog_or_tty->print_cr("      age range     survival rate (avg)      samples (avg)");
   236   gclog_or_tty->print_cr("  ---------------------------------------------------------");
   238   size_t index = 0;
   239   size_t limit = MIN2((int) length, 10);
   240   while (index < limit) {
   241     gclog_or_tty->print_cr("           %4d                 %6.2lf%%             %6.2lf",
   242                   index, _summary_surv_rates[index]->avg() * 100.0,
   243                   (double) _summary_surv_rates[index]->num());
   244     ++index;
   245   }
   247   gclog_or_tty->print_cr("  ---------------------------------------------------------");
   249   int num = 0;
   250   double sum = 0.0;
   251   int samples = 0;
   252   while (index < length) {
   253     ++num;
   254     sum += _summary_surv_rates[index]->avg() * 100.0;
   255     samples += _summary_surv_rates[index]->num();
   256     ++index;
   258     if (index == length || num % 10 == 0) {
   259       gclog_or_tty->print_cr("   %4d .. %4d                 %6.2lf%%             %6.2lf",
   260                     (index-1) / 10 * 10, index-1, sum / (double) num,
   261                     (double) samples / (double) num);
   262       sum = 0.0;
   263       num = 0;
   264       samples = 0;
   265     }
   266   }
   268   gclog_or_tty->print_cr("  ---------------------------------------------------------");
   269 }
   270 #endif // PRODUCT

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