From cbaf52b09971edf6f3e1458f7dd677b80a1568ed Mon Sep 17 00:00:00 2001
From: Konstantin Ritt <ritt.ks@gmail.com>
Date: Mon, 16 Apr 2012 14:43:27 +0300
Subject: [PATCH] QThreadPool: optimize enqueueTask() for common case
the most-common case is: queue is empty or filled with tasks of
the same priority; so the runnable would be put at the end of queue.
both checks are cheap for us.
also avoid detach()'ing by using const iterators
Change-Id: Iab2255f852211f9accc8d717f778671661210ef3
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
---
src/corelib/thread/qthreadpool.cpp | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
diff --git a/src/corelib/thread/qthreadpool.cpp b/src/corelib/thread/qthreadpool.cpp
index b7021817c52..870f943a63c 100644
--- a/src/corelib/thread/qthreadpool.cpp
+++ b/src/corelib/thread/qthreadpool.cpp
@@ -47,15 +47,6 @@
QT_BEGIN_NAMESPACE
-inline bool operator<(int priority, const QPair<QRunnable *, int> &p)
-{
- return p.second < priority;
-}
-inline bool operator<(const QPair<QRunnable *, int> &p, int priority)
-{
- return priority < p.second;
-}
-
Q_GLOBAL_STATIC(QThreadPool, theInstance)
/*
@@ -209,15 +200,22 @@ bool QThreadPoolPrivate::tryStart(QRunnable *task)
return true;
}
+inline bool operator<(int priority, const QPair<QRunnable *, int> &p)
+{ return p.second < priority; }
+inline bool operator<(const QPair<QRunnable *, int> &p, int priority)
+{ return priority < p.second; }
+
void QThreadPoolPrivate::enqueueTask(QRunnable *runnable, int priority)
{
if (runnable->autoDelete())
++runnable->ref;
// put it on the queue
- QList<QPair<QRunnable *, int> >::iterator at =
- qUpperBound(queue.begin(), queue.end(), priority);
- queue.insert(at, qMakePair(runnable, priority));
+ QList<QPair<QRunnable *, int> >::const_iterator begin = queue.constBegin();
+ QList<QPair<QRunnable *, int> >::const_iterator it = queue.constEnd();
+ if (it != begin && priority < (*(it - 1)).second)
+ it = qUpperBound(begin, --it, priority);
+ queue.insert(it - begin, qMakePair(runnable, priority));
runnableReady.wakeOne();
}
--
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