jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/concurrentG1RefineThread.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, 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

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    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

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    25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINETHREAD_HPP

    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINETHREAD_HPP

    28 #include "gc_implementation/shared/concurrentGCThread.hpp"

    30 // Forward Decl.

    31 class CardTableEntryClosure;

    32 class ConcurrentG1Refine;

    34 // The G1 Concurrent Refinement Thread (could be several in the future).

    36 class ConcurrentG1RefineThread: public ConcurrentGCThread {

    37   friend class VMStructs;

    38   friend class G1CollectedHeap;

    40   double _vtime_start;  // Initial virtual time.

    41   double _vtime_accum;  // Initial virtual time.

    42   uint _worker_id;

    43   uint _worker_id_offset;

    45   // The refinement threads collection is linked list. A predecessor can activate a successor

    46   // when the number of the rset update buffer crosses a certain threshold. A successor

    47   // would self-deactivate when the number of the buffers falls below the threshold.

    48   bool _active;

    49   ConcurrentG1RefineThread* _next;

    50   Monitor* _monitor;

    51   ConcurrentG1Refine* _cg1r;

    53   // The closure applied to completed log buffers.

    54   CardTableEntryClosure* _refine_closure;

    56   int _thread_threshold_step;

    57   // This thread activation threshold

    58   int _threshold;

    59   // This thread deactivation threshold

    60   int _deactivation_threshold;

    62   void sample_young_list_rs_lengths();

    63   void run_young_rs_sampling();

    64   void wait_for_completed_buffers();

    66   void set_active(bool x) { _active = x; }

    67   bool is_active();

    68   void activate();

    69   void deactivate();

    71 public:

    72   virtual void run();

    73   // Constructor

    74   ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread* next,

    75                            CardTableEntryClosure* refine_closure,

    76                            uint worker_id_offset, uint worker_id);

    78   void initialize();

    80   // Printing

    81   void print() const;

    82   void print_on(outputStream* st) const;

    84   // Total virtual time so far.

    85   double vtime_accum() { return _vtime_accum; }

    87   ConcurrentG1Refine* cg1r() { return _cg1r;     }

    89   // shutdown

    90   void stop();

    91 };

    93 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINETHREAD_HPP

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

src/share/vm/gc_implementation/g1/concurrentG1RefineThread.hpp@e7d0505c8a30

src/share/vm/gc_implementation/g1/concurrentG1RefineThread.hpp