[Spice-devel] video performance in rhel/centos 7 vs fedora 20

[Marc-André Lureau]

Hi

----- Original Message -----
> Hi All,
> 
> We have been piloting deployments of VM using Fedora 20 host and guest
> and have been very happy with performance and stability in almost every
> respect, so a big thanks to all for this hard work. Things are looking
> great.
> 
> Now we have been testing deployments of these same VMs (F20 guests) on
> rhel 7 (centos 7). We migrated one over and one of the issues seems to
> be a severe degradation of video performance vis-a-vis the F20 host.

The difference between rhel7 and f20 host is quite surprising. I get
quite bad performance with f20 host as well (spice 0.12.4-3, qemu 2.0.0-5)

Are your host configured with the same spice settings (in particular
streaming-video and other compression settings) ?

> The setup is a C7 host, F20 guest and either C7 or F20 client, either
> local to the host or on the LAN.
> 
> In this setup, the video plays fine for a few seconds, but eventually
> degrades to about 1fps with severe tearing of the video. Video does
> remain in sync with audio and there are no audio breakups.
>
> Any pointers on things to try?

I have been investigating some video rendering issues with rhel7 guest
on rhel7 host, see https://bugzilla.redhat.com/show_bug.cgi?id=1030024

However, even with the cogl fix and "PutImage BIG-REQUEST", the video
regions seems to vary too much for the Spice video filter to perform
well (using firefox/html5 video youtube). I believe it will need to be
improved.

(the cogl fix allows much more accurate region invalidation, the
big-request allows to update whole region atomically and not by chunks)

> I'm willing to rebuild some host components (e.g. spice-server or qemu
> or whatever) or try some patches or configuration changes to address
> this to track it down.

Your help would be most welcome to investigate and improve this further.