On 24. Dec 2008, at 14:10, Robert Osfield wrote:
If things are performing under Windows it's most likely a driver issue. I can't see any reason why the way that the OSG is opening up windows under Windows, or he lack of gpu affinity extension as being the problem as normally the screen number and GPU attached to to the associated physical screen should provide all the info the driver needs to map things correctly. Linux/X11 works just fine with just the screen number so doesn't have any more information or controls that would make it behave differently, so it's all down to the driver/windowing system. Now it might be that the NVidia drivers under windows are a bit screwed when it comes to driving multiple displays and that one has to add the extra extension usage to give it the kick up the butt that it needs to do the right thing. Try experimenting with the gpu affinity extension see if it makes any difference.
The default under windows is that all GL commands go to all GPU's, so that one can drag a window across multiple GPU's.
The default on X11 is the opposite - you only see GL on the screen you've used to open the display connection.
The GPU affinity extension limits the GL commands to a subset of your GPU's. I've done tests showing that it gives you ~15% faster performance on a dual-GPU system. The window was only on one screen/ GPU. Sample code and tests can be easily done with Equalizer (see signature).
The extension is only available on Quadro cards, and a bit tricky to use. You have to create a temporary GL context to get the extension function pointers _on a screen driven by an nVidia card_.
HTH, Stefan. -- http://www.eyescale.ch http://www.equalizergraphics.com http://www.linkedin.com/in/eilemann _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
