virt-manager and virgl / Spice / OpenGL

[Scott Talbert]

On Tue, 19 May 2020, Marc-André Lureau wrote:

>> Hi,
>>
>> Is virgl/OpenGL support through virt-manager supposed to work and perform
>> well?
>>
>> I have the following:
>> Host OS: Fedora 32
>> Guest OS: Debian Unstable
>>
>> In virt-manager, I have the following:
>> Display Spice
>>    Type: Spice server
>>    Listen type: None
>>    Password: Blank
>>    Keymap: Blank
>>    OpenGL: Checked & /dev/dri/renderD128
>>
>> Video Virtio
>>    Model: Virtio
>>    Ram: -
>>    Heads: 1
>>    3D acceleration: Checked
>>
>> In the guest OS:
>> talbert at debian-unstable:~$ sudo dmesg | grep '\[drm\]'
>> [    1.947975] [drm] pci: virtio-vga detected at 0000:00:01.0
>> [    2.019988] [drm] features: +virgl +edid
>> [    2.022522] [drm] number of scanouts: 1
>> [    2.022529] [drm] number of cap sets: 2
>> [    2.048982] [drm] cap set 0: id 1, max-version 1, max-size 308
>> [    2.049125] [drm] cap set 1: id 2, max-version 2, max-size 688
>> [    2.049332] [drm] Initialized virtio_gpu 0.1.0 0 for virtio0 on minor 0
>>
>> So it *seems* like things are configured correctly?  However, performance
>> is not great.  Performance is much better if I switch back to QXL video.
>
> It looks like your setup should be fine. What performance are you
> running? Local or remote? If it's 2D based anyway, chances are you get
> similar results with QXL or virtio, probably with better QXL results
> with the QXL Xorg driver.

It's local.  I don't have any quantitative data on performance, just my 
observations on performance.  In the guest, I'm just running the default 
Debian DE (Gnome Shell) on Xorg.  Wayland performs worse.  Gnome Shell is 
3D, right?

Thanks,
Scott