jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/survRateGroup.hpp@e7d0505c8a30

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

     1 /*

     2  * Copyright (c) 2001, 2012, 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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_SURVRATEGROUP_HPP

    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_SURVRATEGROUP_HPP

    28 #include "utilities/numberSeq.hpp"

    30 class G1CollectorPolicy;

    32 class SurvRateGroup : public CHeapObj<mtGC> {

    33 private:

    34   G1CollectorPolicy* _g1p;

    35   const char* _name;

    37   size_t  _stats_arrays_length;

    38   double* _surv_rate;

    39   double* _accum_surv_rate_pred;

    40   double  _last_pred;

    41   double  _accum_surv_rate;

    42   TruncatedSeq** _surv_rate_pred;

    43   NumberSeq**    _summary_surv_rates;

    44   size_t         _summary_surv_rates_len;

    45   size_t         _summary_surv_rates_max_len;

    47   int _all_regions_allocated;

    48   size_t _region_num;

    49   size_t _setup_seq_num;

    51 public:

    52   SurvRateGroup(G1CollectorPolicy* g1p,

    53                 const char* name,

    54                 size_t summary_surv_rates_len);

    55   void reset();

    56   void start_adding_regions();

    57   void stop_adding_regions();

    58   void record_surviving_words(int age_in_group, size_t surv_words);

    59   void all_surviving_words_recorded(bool propagate);

    60   const char* name() { return _name; }

    62   size_t region_num() { return _region_num; }

    63   double accum_surv_rate_pred(int age) {

    64     assert(age >= 0, "must be");

    65     if ((size_t)age < _stats_arrays_length)

    66       return _accum_surv_rate_pred[age];

    67     else {

    68       double diff = (double) (age - _stats_arrays_length + 1);

    69       return _accum_surv_rate_pred[_stats_arrays_length-1] + diff * _last_pred;

    70     }

    71   }

    73   double accum_surv_rate(size_t adjustment);

    75   TruncatedSeq* get_seq(size_t age) {

    76     if (age >= _setup_seq_num) {

    77       guarantee( _setup_seq_num > 0, "invariant" );

    78       age = _setup_seq_num-1;

    79     }

    80     TruncatedSeq* seq = _surv_rate_pred[age];

    81     guarantee( seq != NULL, "invariant" );

    82     return seq;

    83   }

    85   int next_age_index();

    86   int age_in_group(int age_index) {

    87     int ret = (int) (_all_regions_allocated - age_index);

    88     assert( ret >= 0, "invariant" );

    89     return ret;

    90   }

    91   void finished_recalculating_age_indexes() {

    92     _all_regions_allocated = 0;

    93   }

    95 #ifndef PRODUCT

    96   void print();

    97   void print_surv_rate_summary();

    98 #endif // PRODUCT

    99 };

   101 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_SURVRATEGROUP_HPP

Mercurial > jdk8-mips64-public > hotspot / file revision

src/share/vm/gc_implementation/g1/survRateGroup.hpp@e7d0505c8a30

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