[Qt-interest] Xorg performance

[Andre Somers]

On 28-5-2010 13:41, Matthew Fincham wrote:
> On 27-05-10 19:23, Zeljko wrote:
>    
>> Matthew Fincham wrote:
>>
>>
>>
>>      
>>> Further investigation has found that using the command line option
>>> "-graphicssystem raster" improves the performance dramatically.
>>> The downside to this is that the application I am working on uses
>>> "qt_x11Handler(QPaintDevice*)" to resolve a drawable for a QPaintDevice
>>> and this is returning 0 in this mode.
>>>
>>> Any hints would be appreciated.
>>>
>>>        
>> Why don't you use update() instead of repaint() in timer
>>      
> I found that setting Xorg to use the EXA architecture improved the
> performance dramatically. This poses a problem though, as this software
> is running on older systems that do not support the EXA architecture,
> only XAA.
>
> Does anyone know what is causing this?
>
> It is quite disappointing. Updating to the latest and greatest Qt only
> to find that even a simple program runs with appalling performance, and
> software that was running fine with Qt3, under Qt4, performance wise, is
> unusable.
>
>    
I think you have no idea on how to measure the real life performance of 
an application. Your test, IMHO, shows nothing. Real life Qt 
applications do not have an "appaling" or "unusable" performance at all.

I am not a specialist on this topic either, but perhaps you should 
re-read some of the old blogs of "Graphics Ninja" Zack Russin. He 
blogged about this kind of so-called benchmarks several times.

André