Changeset 167526 in webkit

Timestamp:

Apr 18, 2014 8:23:03 PM (10 years ago)

Author:

ggaren@apple.com

Message:

bmalloc: AsyncTask should use Mutex instead of std::mutex
​https://bugs.webkit.org/show_bug.cgi?id=131865

Reviewed by Gavin Barraclough.

std::mutex is so slow that it makes parallelizing simple tasks through
AsyncTask a net regression. Mutex fixes this.

• bmalloc/AsyncTask.h:

(bmalloc::Function>::AsyncTask):
(bmalloc::Function>::join):
(bmalloc::Function>::runSlowCase):
(bmalloc::Function>::entryPoint):

• bmalloc/Mutex.h:

(bmalloc::Mutex::init):

Location:

trunk/Source/bmalloc

Files:

• ChangeLog (modified) (1 diff)
• bmalloc/AsyncTask.h (modified) (6 diffs)
• bmalloc/Mutex.h (modified) (2 diffs)

trunk/Source/bmalloc/ChangeLog

@@ +1 @@
+2014-04-18  Geoffrey Garen  <ggaren@apple.com>
+
+        bmalloc: AsyncTask should use Mutex instead of std::mutex
+        https://bugs.webkit.org/show_bug.cgi?id=131865
+
+        Reviewed by Gavin Barraclough.
+
+        std::mutex is so slow that it makes parallelizing simple tasks through
+        AsyncTask a net regression. Mutex fixes this.
+
+        * bmalloc/AsyncTask.h:
+        (bmalloc::Function>::AsyncTask):
+        (bmalloc::Function>::join):
+        (bmalloc::Function>::runSlowCase):
+        (bmalloc::Function>::entryPoint):
+        * bmalloc/Mutex.h:
+        (bmalloc::Mutex::init):
+
 2014-04-18  Geoffrey Garen  <ggaren@apple.com>
 

trunk/Source/bmalloc/bmalloc/AsyncTask.h

@@ -29 +29 @@
 #include "BAssert.h"
 #include "Inline.h"
+#include "Mutex.h"
 #include <atomic>
 #include <condition_variable>
@@ -56 +57 @@
     std::atomic<State> m_state;
 
-    std::mutex m_conditionMutex;
-    std::condition_variable m_condition;
+    Mutex m_conditionMutex;
+    std::condition_variable_any m_condition;
     pthread_t m_thread;
 
@@ -74 +75 @@
     , m_function(function)
 {
+    m_conditionMutex.init();
 }
 
@@ -82 +84 @@
         return;
 
-    { std::lock_guard<std::mutex> lock(m_conditionMutex); }
+    { std::lock_guard<Mutex> lock(m_conditionMutex); }
     m_condition.notify_one();
 
@@ -105 +107 @@
 
     if (oldState == Sleeping) {
-        { std::lock_guard<std::mutex> lock(m_conditionMutex); }
+        { std::lock_guard<Mutex> lock(m_conditionMutex); }
         m_condition.notify_one();
         return;
@@ -132 +134 @@
         expectedState = Running;
         if (m_state.compare_exchange_weak(expectedState, Sleeping)) {
-            std::unique_lock<std::mutex> lock(m_conditionMutex);
+            std::unique_lock<Mutex> lock(m_conditionMutex);
             m_condition.wait_for(lock, exitDelay, [=]() { return this->m_state != Sleeping; });
         }

trunk/Source/bmalloc/bmalloc/Mutex.h

@@ -34 +34 @@
 namespace bmalloc {
 
-class Mutex {
+struct Mutex {
 public:
+    void init();
+
     void lock();
     bool try_lock();
@@ -45 +47 @@
     std::atomic_flag m_flag;
 };
+
+inline void Mutex::init()
+{
+    m_flag.clear();
+}
 
 inline bool Mutex::try_lock()