Re: Graphics performance on wayland vs eglfs

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Hello,

I think that it is expected to get better performance out of Qt rendering with EGLFS instead of having compositor in the middle. 
With EGLFS Qt can directly render to the screen but without it it would cycle through Weston (or what ever compositor is used) causing separate buffers being composited.

One way to optimize the performance is replace the reference compositor with your own which can be easily done with Qt Wayland compositor API's or by using Qt Application Manager.
Both allows you to have 1st class rendering (directly to screen using EGLFS) and 2nd class rendering through Wayland. In this case only the parts that would be using 2nd would suffer from the extra cycle.

How well something works depends from GPU and GPU Drivers e.g. I've seen use cases where proprietary Vivante drivers have been faster than etnaviv and vice versa.
In any case single full screen rendering will be fastest if you do it directly with GPU without separate compositor in the between. 

Best regards,
Risto Avila

From: agl-dev-community@xxxxxxxxxxxxxxxxxxxxxxxxx <agl-dev-community@xxxxxxxxxxxxxxxxxxxxxxxxx> on behalf of Marius Vlad via lists.automotivelinux.org <marius.vlad=collabora.com@xxxxxxxxxxxxxxxxxxxxxxxxx>
Sent: Tuesday, February 8, 2022 16:43
To: agl-dev-community@xxxxxxxxxxxxxxxxxxxxxxxxx <agl-dev-community@xxxxxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: Graphics performance on wayland vs eglfs
 
Wrt to the cluster question, see Scott's answer:

https://lists.automotivelinux.org/g/agl-dev-community/message/9626


On 2/8/22 2:41 PM, Paulo Sherring wrote:
> Hello all,
>
> I am working (more accurately playing around) on an Instrument Cluster
> application. I am currently based on master and it is basically the same IC
> application we had in past branches.
> I am currently experimenting with GFX (effects, animations, fade in, fade
> out) and video playback.
>
> One thing that I noticed is that if I don't use Wayland (i.e., no
> running compositor and passing QT_QPA_PLATFORM=eglfs), I get much smoother
> graphics, so much that it is visible to the eyes: smoother opacity
> changing, smoother video playback, visual effects such as QML Glow becomes
> really efficient.
>
> So, my question is: is there a way of getting eglfs equivalent performance
> when using Wayland?


This is quite vague, I guess some real numbers could tell how much of a
difference you're seeing between the two. With mesa drivers you could
use GALLIUM_HUD=cpu,fps and have a look at both. Probably that's
possible with rpi4 but probably not with r-car. Same with vivante vs
etnaviv. What platform you're using? Are you sure you're using the GPU
and not llvmpipe/softpipe?

Itself wayland is just a protocol not a drawing API so there's nothing
to make it much for faster, than it currently is. Not really sure what
to recommend at this point, but I guess a difference between the two is
the fact that with Wayland you have multiple clients
and you have composite imagine, while with eglfs you have a single,
full-screen application. But even so,
compositors attempts to make use of the HW, if available, just like
probably happens with eglfs and the KMS backend.

It is rather hard at this point to tell, without some specific use-cases
to compare and more information on the matter.

>
> BTW, in regards to IC images on the master branch, do we still get
> agl-cluster somehow? If not, will we get it again? I couldn't find it on
> master nor on the docs and proceedings.
>
> Kind regards,
> Paulo Sherring.
>
>
>
>
>
>

--
Marius Vlad





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