Profiling C++/Qt project in vs 2010 points to winEventFilter()

[pjuske]

I am trying to enhance the performance of my project which, in brief, captures image and does image processing tasks subsequently.
I am using the QT-library and Intel's IPP for image processing, being stuck with severe performance issue.

At the begin, I thought the image analysis functions would cause the time troubles, but when using the Instrumentation-Analysis of VS2010 Profiling tool, the WinEventFilter()calling QTCored4.dll consumes the most exclusive time, while processing time of the image ipp function insignificant.
To my understnding, the winEvent function handles e.g. mouse and keyboard interactions and all the things connected to display.

I could understand if Qt-Functions respectively the winEventFilter yield high inclusive time, but not high exclusive times?!

Does someone have an explanation or could turn my attention to some specific further investigation to isolate the problem?!

Thanks in advance, Peter

<pre>Profiler-Output:
86% exclusive time by QtCored4.dll
--> function details for QtCored4.dll:
Function that called QtCored4.dll : QCoreApplication::winEventFilter
Remarkably the winEventFilter has a very high 'elapsed exclusive time' but a small 'apllication exclusive time' (that is without IO and stuff)</pre>