Hitting X limit in launching maximum number of vkcube instances

[Olivier Fourdan]

Hi

On Thu, May 18, 2023 at 10:45 AM Anuj Phogat <anuj.phogat at gmail.com> wrote:
>
> On Sat, May 6, 2023 at 9:04 AM Alan Coopersmith
> <alan.coopersmith at oracle.com> wrote:
> >
> > On 5/5/23 16:07, Anuj Phogat wrote:
> > > Thanks for the quick response Adam. I've seen this behavior across multiple
> > > graphics applications
> > > and graphics drivers. This is an extreme use case I'm trying out. So, there's a
> > > possibility of this use
> > > case not being handled correctly by any of the applications or graphics drivers.
> > > But I also see some basic X functionality, like closing the window using the "x"
> > > button, not working
> > > properly with windows opened past the 256 limit. This happens with a modified
> > > limit of 512. I had to
> > > use xkill to close those windows. Any thoughts about this?
> >
> > Closing the window with the "x" button is a function of the window manager.
> > Does the window manager you are using assume the number of X clients is
> > limited to 256?  That xkill works suggests the X server is handling it
> > correctly.
> Alan, I took the window manager out of the equation by running multiple
> instances of vkcube with Xorg without running any window manager.
> Xorg.0.log file does show a log about set max clients through a .conf file:
> (**) Option "MaxClients" "512"
>
> But, I start seeing below error messages at the end of the log file once
> the number of vkcube instances go past 256:
> "_XSERVTransSocketUNIXAccept: accept() failed"
>
> Seems like the modified max clients limit of 512 is not getting configured
> correctly in X.
>
> What can I do to fix / debug this error ?

I didn't find a mention of the actual version of the Xserver you're
running (not knowing what Ubuntu ships), but this may be relevant for
your issue:

https://gitlab.freedesktop.org/xorg/xserver/-/issues/1310

Fixed with:

https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/937

And backported to the 21.1 branch with:

https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/953

HTH

Cheers

Olivier