[ovirt-users] 100% memory usage on desktop environments

[David Jaša]

On St, 2016-05-18 at 16:52 +0100, Nicolás wrote:
> Hi,
> 
> Probably not an oVirt issue, but maybe someone can help. I've deployed a 
> pretty basic VM (ubuntu 14.04 server, 4GB RAM, 4 CPUs, 15GB storage). 
> Each time I install an additional desktop environment (Gnome, KDE, 
> whatever...), CPU usage rises to 100% all time to the extreme that 
> interacting with the machine becomes impossible (maybe a mouse movement 
> is propagated 3 minutes later or so...).
> 
> To debug this, I installed LXDE, which is a lightweight desktop 
> environment based on Xorg. I could see there is an Xorg process 
> consuming one of the CPUs and the machine stops responding as far as the 
> desktop environment goes. I have not changed anything in the 
> configuration file.
> 
> I could also see this only happens when QXL is chosen as the display 
> driver. When CIRRUS is chosen, everything works smoothly and CPU is 
> ~100% idle. The downside is that we want to use SPICE and CIRRUS won't 
> allow it.
> 
> Why does this happen? Is this an OS-side driver issue? Any hint how can 
> it be fixed?
> 
> Thanks.
> 
> Nicolás
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Try disabling KMS (by blacklisting qxl module). IIRC it was new by 14.04
release time while UMS was already mature.

David