Re: Graphics performance on wayland vs eglfs

["Paulo Sherring" <pauloasherring@xxxxxxxxx>]

Hello Marius,
Thanks for the quick reply, as always :)
I know that KPIs and more information were really missing, I was
trying to find a way to reliability measure FPS to no avail.
Thanks for suggesting the GALLIUM_HUD, worked really nice! Please, see
below for some more information.

> Platform:
The platform I use is RPi4, 2GiB.
Configs are the same stock agl-compositor, except for
transform=normal. Full config: https://pastebin.com/2a8nn7DV
App is built using default compiler flags and in debug.

> Use-case:
QML based app, that plays a video on startup, applies a fade-out as
the video gets closer to the end.
The QML app uses some animations to change properties on a QML Glow object.
Side note on this Glow stuff: Qt (5.14.2) version I am using likely
has some memory leak because when enabled, memory gets chewed up in 3
minutes or so.

> Measurements with GALLIUM_HUD:
eglfs:
Still pic: https://imgur.com/wqlcVHe
Video: https://youtu.be/42G7x8G4JcE
Observed behavior: smoother playback, fadeout, lower CPU usage, higher
and steadier fps

wayland (agl-compositor):
Still pic: https://imgur.com/fCuSUEo
Video: https://youtu.be/V3woUyn1Pts
Observed behavior: worse in all aspects wrt to eglfs.

> Are you sure you're using the GPU and not llvmpipe/softpipe?
No, at this point, I am not sure at all. Both runs were using the same
built image, I just changed the platform.
But, as you mentioned, I'd expect that agl-compositor and the DRM
backend are making use of the GPU.
In regards to eglfs vs using wayland, I'd expect that there would be
some extra effort to move around requests to the compositor, but not
to necessarily to the point impacting like this the performance.
Using gstreamer (gst-launcher) + weston directly, I found that I can
playback a video with no glitches. I couldn't use gst-launcher
directly with agl-compositor (nothing showed on the screen), but I'd
expect that as agl-compositor uses some extra APIs (shell extensions?)
to enable the surface visibility. Do I get this right?

So, I am now thinking that there is something going on with Qt itself.
Are there some knobs I could turn to change things in regards to
wayland platform on Qt?

Regards, Paulo.

On Tue, Feb 8, 2022 at 2:43 PM Marius Vlad <marius.vlad@xxxxxxxxxxxxx> wrote:
>
> 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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