jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1StringDedupThread.cpp@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) 2014, 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.

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    23  */

    25 #include "precompiled.hpp"

    26 #include "gc_implementation/g1/g1Log.hpp"

    27 #include "gc_implementation/g1/g1StringDedup.hpp"

    28 #include "gc_implementation/g1/g1StringDedupTable.hpp"

    29 #include "gc_implementation/g1/g1StringDedupThread.hpp"

    30 #include "gc_implementation/g1/g1StringDedupQueue.hpp"

    32 G1StringDedupThread* G1StringDedupThread::_thread = NULL;

    34 G1StringDedupThread::G1StringDedupThread() :

    35   ConcurrentGCThread() {

    36   set_name("String Deduplication Thread");

    37   create_and_start();

    38 }

    40 G1StringDedupThread::~G1StringDedupThread() {

    41   ShouldNotReachHere();

    42 }

    44 void G1StringDedupThread::create() {

    45   assert(G1StringDedup::is_enabled(), "String deduplication not enabled");

    46   assert(_thread == NULL, "One string deduplication thread allowed");

    47   _thread = new G1StringDedupThread();

    48 }

    50 G1StringDedupThread* G1StringDedupThread::thread() {

    51   assert(G1StringDedup::is_enabled(), "String deduplication not enabled");

    52   assert(_thread != NULL, "String deduplication thread not created");

    53   return _thread;

    54 }

    56 void G1StringDedupThread::print_on(outputStream* st) const {

    57   st->print("\"%s\" ", name());

    58   Thread::print_on(st);

    59   st->cr();

    60 }

    62 void G1StringDedupThread::run() {

    63   G1StringDedupStat total_stat;

    65   initialize_in_thread();

    66   wait_for_universe_init();

    68   // Main loop

    69   for (;;) {

    70     G1StringDedupStat stat;

    72     stat.mark_idle();

    74     // Wait for the queue to become non-empty

    75     G1StringDedupQueue::wait();

    76     if (_should_terminate) {

    77       break;

    78     }

    80     {

    81       // Include thread in safepoints

    82       SuspendibleThreadSetJoiner sts;

    84       stat.mark_exec();

    86       // Process the queue

    87       for (;;) {

    88         oop java_string = G1StringDedupQueue::pop();

    89         if (java_string == NULL) {

    90           break;

    91         }

    93         G1StringDedupTable::deduplicate(java_string, stat);

    95         // Safepoint this thread if needed

    96         if (sts.should_yield()) {

    97           stat.mark_block();

    98           sts.yield();

    99           stat.mark_unblock();

   100         }

   101       }

   103       G1StringDedupTable::trim_entry_cache();

   105       stat.mark_done();

   107       // Print statistics

   108       total_stat.add(stat);

   109       print(gclog_or_tty, stat, total_stat);

   110     }

   111   }

   113   terminate();

   114 }

   116 void G1StringDedupThread::stop() {

   117   {

   118     MonitorLockerEx ml(Terminator_lock);

   119     _thread->_should_terminate = true;

   120   }

   122   G1StringDedupQueue::cancel_wait();

   124   {

   125     MonitorLockerEx ml(Terminator_lock);

   126     while (!_thread->_has_terminated) {

   127       ml.wait();

   128     }

   129   }

   130 }

   132 void G1StringDedupThread::print(outputStream* st, const G1StringDedupStat& last_stat, const G1StringDedupStat& total_stat) {

   133   if (G1Log::fine() || PrintStringDeduplicationStatistics) {

   134     G1StringDedupStat::print_summary(st, last_stat, total_stat);

   135     if (PrintStringDeduplicationStatistics) {

   136       G1StringDedupStat::print_statistics(st, last_stat, false);

   137       G1StringDedupStat::print_statistics(st, total_stat, true);

   138       G1StringDedupTable::print_statistics(st);

   139       G1StringDedupQueue::print_statistics(st);

   140     }

   141   }

   142 }

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

src/share/vm/gc_implementation/g1/g1StringDedupThread.cpp@e7d0505c8a30

src/share/vm/gc_implementation/g1/g1StringDedupThread.cpp