Changeset 91082 in webkit for trunk/Source/JavaScriptCore/wtf/ThreadIdentifierDataPthreads.cpp

Timestamp:

Jul 15, 2011, 11:49:24 AM (14 years ago)

Author:

[email protected]

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.

File:

• trunk/Source/JavaScriptCore/wtf/ThreadIdentifierDataPthreads.cpp (modified) (4 diffs)

trunk/Source/JavaScriptCore/wtf/ThreadIdentifierDataPthreads.cpp

@@ -39 +39 @@
 namespace WTF {
 
-pthread_key_t ThreadIdentifierData::m_key;
-static pthread_once_t onceControl = PTHREAD_ONCE_INIT;
+pthread_key_t ThreadIdentifierData::m_key = PTHREAD_KEYS_MAX;
 
 void clearPthreadHandleForIdentifier(ThreadIdentifier);
@@ -49 +48 @@
 }
 
+void ThreadIdentifierData::initializeOnce()
+{
+    if (pthread_key_create(&m_key, destruct))
+        CRASH();
+}
+
 ThreadIdentifier ThreadIdentifierData::identifier()
 {
-    initializeKeyOnce();
+    ASSERT(m_key != PTHREAD_KEYS_MAX);
     ThreadIdentifierData* threadIdentifierData = static_cast<ThreadIdentifierData*>(pthread_getspecific(m_key));
 
@@ -60 +65 @@
 {
     ASSERT(!identifier());
-
-    initializeKeyOnce();
     pthread_setspecific(m_key, new ThreadIdentifierData(id));
 }
@@ -80 +83 @@
 }
 
-void ThreadIdentifierData::initializeKeyOnceHelper()
-{
-    if (pthread_key_create(&m_key, destruct))
-        CRASH();
-}
-
-void ThreadIdentifierData::initializeKeyOnce()
-{
-    if (pthread_once(&onceControl, initializeKeyOnceHelper))
-        CRASH();
-}
-
 } // namespace WTF