[Spice-devel] SPICE Fedora 15 guest X running at 100%

[John A. Sullivan III]

On Wed, 2011-06-15 at 16:08 -0400, John A. Sullivan III wrote:
> Since we were having some trouble as just outlined on our Windows tests,
> we thought we would let SPICE put its best foot forward and try a Fedora
> 15 guest running on a Fedora 15 KVM host.
> 
> When it worked, it was amazing.  However, most of the time, the system
> was barely responsive and the X process was consuming 100% of the CPU.
> We initially thought this might be from KDE4 so we installed twm and
> experienced the same.  We then launched a few applications without any
> Windows Manager at all and saw the same results.
> 
> Alon was helpful on IRC and mentioned that it was because there was no
> kernel module for the driver.
> 
> Does this mean that there is no driver for the QXL driver and thus it
> runs in user space and drives up the utilization? If so, what are people
> doing who are running this in production?
> 
> This leads to another question.  Our understanding is that rendering is
> done on the client and not the guest unless the client is unable to do
> so (haven't read enough on the protocol to understand how this is
> determined).  Does this mean that, in cases where rendering is happening
> on the guest that a high end graphics card in the physical host would
> improve performance? Our experience with using NX is that the physical
> hardware is never involved but that is a completely different paradigm.
> 
> If the rendering is taking place on the client, why is the lack of a
> kernel module for QXL causing a problem? Thanks - John

I checked my Xorg.0.log file and noticed that I was getting persistent
messages about cache failures and out of memory.  It looks like the vram
parameter was set to something like 9216.

So I changed it to 256000.  To my surprise, the SPICE client connected
but I had no mouse and no keyboard.  I stopped the VM and redefined it
with 128000 and I now had keyboard and video but still had the same
excessive X utilization - John