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

[David Mansfield]

On 07/15/2014 11:22 AM, Marc-André Lureau wrote:
> 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) ?
I have not specified any specific settings on the host for spice. If 
there are differences in the defaults then I could play around with 
that. Do you know what the differences might be?

In particular on the F20 side I have:
spice-server-0.12.5-2.fc20.x86_64
qemu-kvm-1.6.2-6.fc20.x86_64

And everything is peachy.

On c7 host I have:
spice-server-0.12.4-5.el7.x86_64
qemu-kvm-1.5.3-60.el7_0_0.2.x86_64


>> 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, seehttps://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.
I think these are both guest side fixes/changes, and my guest is F20, 
(actually the exact same VM as was running before on F20 host, but now 
on C7 host).

So I think the cogl fix is not relevant (and I'm not permitted to see 
the PutImage BIG-REQUEST issue because it's a restricted bug).

I have tried rebuilding the spice-server package from F20 and installing 
on C7 host, but it doesn't change anything.

Which leaves me with qemu changes.  Is there a "version" of the qxl 
hardware that's implemented in qemu that may be different?


> Your help would be most welcome to investigate and improve this further.
I'll do my best :-) .  Sometimes it's just a maze of twisty little 
passages, all alike...

-- 
Thanks,
David Mansfield
Cobite, INC.