Mailing List Archive

On 03/05/2021 12:39, Eyal Lebedinsky wrote:
> For a while I avoided using mythfrontend under kvm as it was mostly
> useless for me.
> Today I tried again and it works better, but playback, while
> watchable, is not smooth at all.
>
> On the VM, watching FHD, when paused it consumes 75% of a cpu, when
> playing 100%.
> Watching HD (720p) it uses 65% playing or paused.
>
> The host and VM are f32 (soon to be f34).
> The host is an 8 core "i7-9700 CPU @ 3.00GHz" with Intel GPU on board
> and no second GPU.

1. What display method are you using between the client and the VM? VNC
is a relatively "dumb" protocol and can be quite bandwidth heavy for
full-screen video, where many pixels change each frame. Consider,
instead, using SPICE which allows for some considerable acceleration, as
well as forwarding of sound from the VM to the client.

2. Is the Intel GPU new enough to support GVT? GVT allows certain Intel
and NVIDIA cards to offer a "virtual card" to VMs. The virtual card can
be used by the host for OpenGL and VAAPI acceleration. While you still
hit the problem of how to get the image from the VM to the screen, being
able to offload MPEG decoding from the virtual CPU to the virtual GPU
might also help you.

https://wiki.archlinux.org/title/Intel_GVT-g gives a nice overview of
the process for getting GVT to work.


>
> What KVM/MythTV settings should I use for optimal performance?
>
> TIA
>

On 03/05/2021 22.16, Darac Marjal wrote:
>
> On 03/05/2021 12:39, Eyal Lebedinsky wrote:
>> For a while I avoided using mythfrontend under kvm as it was mostly
>> useless for me.
>> Today I tried again and it works better, but playback, while
>> watchable, is not smooth at all.
>>
>> On the VM, watching FHD, when paused it consumes 75% of a cpu, when
>> playing 100%.
>> Watching HD (720p) it uses 65% playing or paused.
>>
>> The host and VM are f32 (soon to be f34).
>> The host is an 8 core "i7-9700 CPU @ 3.00GHz" with Intel GPU on board
>> and no second GPU.
>
> 1. What display method are you using between the client and the VM? VNC
> is a relatively "dumb" protocol and can be quite bandwidth heavy for
> full-screen video, where many pixels change each frame. Consider,
> instead, using SPICE which allows for some considerable acceleration, as
> well as forwarding of sound from the VM to the client.

I do use spice for video.

> 2. Is the Intel GPU new enough to support GVT? GVT allows certain Intel
> and NVIDIA cards to offer a "virtual card" to VMs. The virtual card can
> be used by the host for OpenGL and VAAPI acceleration. While you still
> hit the problem of how to get the image from the VM to the screen, being
> able to offload MPEG decoding from the virtual CPU to the virtual GPU
> might also help you.
>
> https://wiki.archlinux.org/title/Intel_GVT-g gives a nice overview of
> the process for getting GVT to work.

I think that I looked into it before and found that this does not provide 4k virtual GPU.
I will need to add the necessary boot options to see the actual resolutions offered. The GPU is:
0000:00:02.0 VGA compatible controller [0300]: Intel Corporation CoffeeLake-S GT2 [UHD Graphics 630] [8086:3e98] (rev 02)

I try to limit experimenting on this machine but will consider this option.

>> What KVM/MythTV settings should I use for optimal performance?
>>
>> TIA

--
Eyal Lebedinsky (eyal@eyal.emu.id.au)
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