Hi,
Just a recap:
We aren't using CompositeViewer- just a Viewer with 4 slave cameras each in
its own window. Each window is opened on a separate graphics card. We're
running X11 which has no issues with graphics card affinity. We aren't
using mosaic mode, twinview, xinerama or anything else fancy- just a simple
mapping of one X display to one graphics card.
We can run four copies of our program at the same time, each displaying to a
separate card and all four can run as fast as a single copy.
If I try running one copy of the program displaying to multiple windows the
frame rate drops as the number of windows increases. If the frame rate for
one window is N, then opening 2 windows gives roughly N/2 FPS, three windows
gives N/3 and so forth. I also get the same results if I open multiple
windows on just one card. I can see N draw threads by running top.
This is true if I use just one copy of the scenegraph, set in the viewer, or
four separate copies of the scenegraph, each loaded in a single slave
camera.
I get similar results for setting serial draw to on or off. (Actually
setting it to on, the default is a bit faster.) I'm using the
culldrawthreadpercontext threading model.
At this point I've run out of OSG things to try, but am open to suggestions.
At this point I'm assuming it's either an Nvidia driver bug or an OSG bug.
(Latest Nvidia driver, OSG 2.8.3)
Thanks,
John
On Wed, 20 Oct 2010, Paul Martz wrote:
On 10/20/2010 1:44 AM, Serge Lages wrote:
Hi,
Here we had a setup with 2 NVidia cards and 4 screens on Linux (2 twinviews), on
the application side we used a CompositeViewer with 2 views and 4 cameras (2
contexts), and we had a solid 60fps without problems :
I think John can also hit 60fps, if he uses a small enough data set, so the
framerate itself is irrelevant. The question is: Do the draw traversals occur
simultaneously, and do they take the same time in the multi-window case as they
do in the single-window case?
In other words, if your data set running single windowed has a combined cull and
draw that just barely fits in 16ms and therefore runs at 60hz, how does that
software perform in the multi-window case? For John, that case drops to 30fps or
15fps, because the combined cull-draw for each window quadruples.
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