XOpenDisplay takes a long time to return

[tom fogal]

You might try 'strace' to see what call[s] are taking that time.

This might be an issue with the nvidia drivers too, which AFAIK are not 
part of X.org or even open source.  But strace should hopefully 
elucidate whether or not that's the case.

-tom

On 06/28/2013 09:09 PM, Divick Kishore wrote:
> Hi,
>      I have installed nvidia OpenGL drivers on amazon gpu cluster
> instance which has two Tesla M2050 GPUs and I see a weird behavior
> when I run any two apps in quick succession.
>
> I am running the server in a headless mode with xorg.conf generated
> using the following options:
>
> sudo nvidia-xconfig -a --no-xinerama --no-dynamic-twinview
> --use-display-device=None --virtual=1280x1024
>
> which maps two screens each of them to two devices.
>
> Finally I run X Server using:
>
> sudo /usr/bin/X :0
>
> and then I run any application on any one of the GPUs using:
>
> #Runs it on first GPU
> export DISPLAY=:0.0 glxgears
>
> #Runs it on second GPU
> export DISPLAY=:0.1 glxgears
>
> I noticed that sometimes it takes a very very long time (~couple of
> seconds to a minute) before a call to XOpenDisplay succeeds. It is not
> clear if the issue is with X server or with nvidia drivers or possibly
> with my xorg settings.
>
> I notice that when an application exits the output is similar to the
> following output (see below below this paragraph) on the terminal
> where I started the X. Only when this is dumped when the previous
> application exits / closes the display, the XOpenDisplay succeeds. So
> it seems that only after either the driver of X does some cleanup the
> subsequent XOpenDisplay succeeds.
>
> 12 XSELINUXs still allocated at reset
> SCREEN: 0 objects of 344 bytes = 0 total bytes 0 private allocs
> COLORMAP: 0 objects of 8 bytes = 0 total bytes 0 private allocs
> DEVICE: 0 objects of 104 bytes = 0 total bytes 0 private allocs
> CLIENT: 0 objects of 152 bytes = 0 total bytes 0 private allocs
> WINDOW: 0 objects of 72 bytes = 0 total bytes 0 private allocs
> PIXMAP: 4 objects of 112 bytes = 448 total bytes 0 private allocs
> ...
> ...
> TOTAL: 8 objects, 320 bytes, 0 allocs
>
>
> Is there someone who could help?
> Regards,
> Divick
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