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Changeset 92154 in webkit


Ignore:
Timestamp:
Aug 1, 2011, 5:10:21 PM (15 years ago)
Author:
levin@chromium.org
Message:

currentThread is too slow!
​https://bugs.webkit.org/show_bug.cgi?id=64577

Reviewed by Darin Adler and Dmitry Titov.

The problem is that currentThread results in a pthread_once call which always takes a lock.
With this change, currentThread is 10% faster than isMainThread in release mode and only
5% slower than isMainThread in debug.

  • wtf/ThreadIdentifierDataPthreads.cpp:

(WTF::ThreadIdentifierData::initializeOnce): Remove the pthread once stuff
which is no longer needed because this is called from initializeThreading().
(WTF::ThreadIdentifierData::identifier): Remove the initializeKeyOnce call because
intialization of the pthread key should already be done.
(WTF::ThreadIdentifierData::initialize): Ditto.

  • wtf/ThreadIdentifierDataPthreads.h:
  • wtf/ThreadingPthreads.cpp:

(WTF::initializeThreading): Acquire the pthread key here.

Location:
trunk/Source/JavaScriptCore
Files:
4 edited

Legend:

Unmodified
Added
Removed

  • trunk/Source/JavaScriptCore/ChangeLog

    r92148 r92154  
     12011-07-14  David Levin  <levin@chromium.org>
     2
     3        currentThread is too slow!
     4        https://bugs.webkit.org/show_bug.cgi?id=64577
     5
     6        Reviewed by Darin Adler and Dmitry Titov.
     7
     8        The problem is that currentThread results in a pthread_once call which always takes a lock.
     9        With this change, currentThread is 10% faster than isMainThread in release mode and only
     10        5% slower than isMainThread in debug.
     11
     12        * wtf/ThreadIdentifierDataPthreads.cpp:
     13        (WTF::ThreadIdentifierData::initializeOnce): Remove the pthread once stuff
     14        which is no longer needed because this is called from initializeThreading().
     15        (WTF::ThreadIdentifierData::identifier): Remove the initializeKeyOnce call because
     16        intialization of the pthread key should already be done.
     17        (WTF::ThreadIdentifierData::initialize): Ditto.
     18        * wtf/ThreadIdentifierDataPthreads.h:
     19        * wtf/ThreadingPthreads.cpp:
     20        (WTF::initializeThreading): Acquire the pthread key here.
     21
    1222011-08-01  Filip Pizlo  <fpizlo@apple.com>
    223

  • trunk/Source/JavaScriptCore/wtf/ThreadIdentifierDataPthreads.cpp

    r91444 r92154  
    3737#include "Threading.h"
    3838
     39#include <limits.h>
     40
    3941namespace WTF {
    4042
    41 pthread_key_t ThreadIdentifierData::m_key;
    42 static pthread_once_t onceControl = PTHREAD_ONCE_INIT;
     43pthread_key_t ThreadIdentifierData::m_key = PTHREAD_KEYS_MAX;
    4344
    4445void clearPthreadHandleForIdentifier(ThreadIdentifier);
    … …  
    4950}
    5051
     52void ThreadIdentifierData::initializeOnce()
     53{
     54    if (pthread_key_create(&m_key, destruct))
     55        CRASH();
     56}
     57
    5158ThreadIdentifier ThreadIdentifierData::identifier()
    5259{
    53     initializeKeyOnce();
     60    ASSERT(m_key != PTHREAD_KEYS_MAX);
    5461    ThreadIdentifierData* threadIdentifierData = static_cast<ThreadIdentifierData*>(pthread_getspecific(m_key));
    5562
    … …  
    6067{
    6168    ASSERT(!identifier());
    62 
    63     initializeKeyOnce();
    6469    pthread_setspecific(m_key, new ThreadIdentifierData(id));
    6570}
    … …  
    8085}
    8186
    82 void ThreadIdentifierData::initializeKeyOnceHelper()
    83 {
    84     if (pthread_key_create(&m_key, destruct))
    85         CRASH();
    86 }
    87 
    88 void ThreadIdentifierData::initializeKeyOnce()
    89 {
    90     if (pthread_once(&onceControl, initializeKeyOnceHelper))
    91         CRASH();
    92 }
    93 
    9487} // namespace WTF
    9588

  • trunk/Source/JavaScriptCore/wtf/ThreadIdentifierDataPthreads.h

    r91444 r92154  
    4343    ~ThreadIdentifierData();
    4444
     45    // One time initialization for this class as a whole.
     46    // This method must be called before initialize() and it is not thread-safe.
     47    static void initializeOnce();
     48
    4549    // Creates and puts an instance of ThreadIdentifierData into thread-specific storage.
    4650    static void initialize(ThreadIdentifier identifier);
    … …  
    6367    static void destruct(void* data);
    6468
    65     static void initializeKeyOnceHelper();
    66     static void initializeKeyOnce();
    67 
    6869    ThreadIdentifier m_identifier;
    6970    bool m_isDestroyedOnce;

  • trunk/Source/JavaScriptCore/wtf/ThreadingPthreads.cpp

    r92068 r92154  
    8787    threadMapMutex();
    8888    initializeRandomNumberGenerator();
     89    ThreadIdentifierData::initializeOnce();
    8990    wtfThreadData();
    9091#if ENABLE(WTF_MULTIPLE_THREADS)
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