Changeset 165687 in webkit for trunk/Source/WTF/wtf/ThreadingPthreads.cpp

Timestamp:

Mar 15, 2014, 5:44:51 PM (11 years ago)

Author:

[email protected]

Message:

It should be possible to adjust DFG and FTL compiler thread priorities
​https://bugs.webkit.org/show_bug.cgi?id=130288

Reviewed by Filip Pizlo.

Added ability to change thread priorities relative to its current priority.
Created options to adjust the priority of the DFG and FTL compilation work thread
pools. For two core systems, there might be three runnable threads, the main thread,
the DFG compilation thread and the FTL compilation thread. With the same priority,
the scheduler is free to schedule whatever thread it wants. By lowering the
compilation threads, the main thread can run. Further tests may suggest better values
for the new options, priorityDeltaOfDFGCompilerThreads and priorityDeltaOfFTLCompilerThreads.

For a two-core device, this change has a net positive improvement of 1-3% across
SunSpider, Octane, Kraken and AsmBench.

File:

• trunk/Source/WTF/wtf/ThreadingPthreads.cpp (modified) (1 diff)

trunk/Source/WTF/wtf/ThreadingPthreads.cpp

@@ -204 +204 @@
     ThreadIdentifierData::initialize(id);
 }
-
+    
+void changeThreadPriority(ThreadIdentifier threadID, int delta)
+{
+    pthread_t pthreadHandle;
+    ASSERT(threadID);
+
+    {
+        // We don't want to lock across the call to join, since that can block our thread and cause deadlock.
+        MutexLocker locker(threadMapMutex());
+        pthreadHandle = pthreadHandleForIdentifierWithLockAlreadyHeld(threadID);
+        ASSERT(pthreadHandle);
+    }
+
+    int policy;
+    struct sched_param param;
+
+    if (pthread_getschedparam(pthread_self(), &policy, &param))
+        return;
+
+    param.sched_priority += delta;
+
+    pthread_setschedparam(pthread_self(), policy, &param);
+}
+    
 int waitForThreadCompletion(ThreadIdentifier threadID)
 {