[Xcb] Question about xcb performance and threading support

[Benoît Minisini]

> HI Benoît,
>
> > I have currently using valgrind / callgrind & kcachegrind with the Gambas
> > IDE to try to understand why QT4.4 is slower than QT3.
>
> QT4 is now double-buffered, furthermore it uses antialiasing for a lot
> of its widgets and has a new painting engine which uses XRender
> trapezoids. Unfourtunatly the trapezoids are not hw accalerated, so
> they are slow compared to what QT3 did.
>
> I am not 100% sure, but when running your benchmarks pay attention to
> the time spent in Xorg in relation to the QT client.
>
> - Clemens

For information:

The slowness of QT4 seems to come more from lack of optimizations in their 
backings store routines than from XRender. That should be solved in QT 4.5, 
according to their blogs:

http://labs.trolltech.com/blogs/2009/02/13/bnilsenflush/

Regards,

-- 
Benoît