Go to System Settings > Display and Monitor > Compositor and set Latency to Force smoothest animations. That fixed it for me.

Thank you, it makes thing better, but from time to time it still stutters.
Under X11, I can move that slider all the way to the left and still have a butter smooth performances with dropped frames from time to time.
Also, I wonder if the added latency by kwin under wayland could be a problem when gaming and if there is a way to disable the effects like it is possible under Xorg right now.

My hardware is not comparable to yours, but for me Wayland has been really good this time around.

Switched full time at new years and haven't looked back. I've tried Wayland many times in the past and finally this time there were no showstoppers left.
No stutter or input lag, it's very smooth using the Balance setting for Kwin compositor. It even feels like gaming performance improved, for DX12 games in Steam/Proton at least. Running dual monitors with different refresh rate and orientation.

KDE + Wayland isn't perfect, but I'm not switching back. That's how good it is.

Quoting: dpanterMy hardware is not comparable to yours, but for me Wayland has been really good this time around.

Switched full time at new years and haven't looked back. I've tried Wayland many times in the past and finally this time there were no showstoppers left.
No stutter or input lag, it's very smooth using the Balance setting for Kwin compositor. It even feels like gaming performance improved, for DX12 games in Steam/Proton at least. Running dual monitors with different refresh rate and orientation.

KDE + Wayland isn't perfect, but I'm not switching back. That's how good it is.

There has to be some input lag since kwin forces vsync on, right?
I often disable desktop effects to force vsync off when not needed, buf AFAIK, this is just not yet possible.

Quoting: kokoko3kThank you, it makes thing better, but from time to time it still stutters.
Under X11, I can move that slider all the way to the left and still have a butter smooth performances with dropped frames from time to time.
Also, I wonder if the added latency by kwin under wayland could be a problem when gaming and if there is a way to disable the effects like it is possible under Xorg right now.

On Wayland, compositor is bypassed for full screen windows, so it should not effect gaming.

One other thing you can try is to switch to Crocus driver and see if it helps. You can do so by adding

MESA_LOADER_DRIVER_OVERRIDE=crocus

to etc/environment

Quoting: Sputnik_tr_02

Quoting: kokoko3kThank you, it makes thing better, but from time to time it still stutters.
Under X11, I can move that slider all the way to the left and still have a butter smooth performances with dropped frames from time to time.
Also, I wonder if the added latency by kwin under wayland could be a problem when gaming and if there is a way to disable the effects like it is possible under Xorg right now.

On Wayland, compositor is bypassed for full screen windows, so it should not effect gaming.

One other thing you can try is to switch to Crocus driver and see if it helps. You can do so by adding

MESA_LOADER_DRIVER_OVERRIDE=crocus

to etc/environment

Even if compositor is bypassed, vsync is still enforced, there are patches flying around that have yet to be merged about it.
I'm already using crocus to no avail, thanks.
One thing i found is that forcing the igp to use higher frequencies make things better (the tradeoff is a bunch of watts).
Another thing that bugs me is that for some reason it is using the software cursor, so when i switch to high latency/smoother animations, the mouse lags too; going to open a bug report about it.

Quoting: kokoko3kThere has to be some input lag

I can't see it or feel it, so I don't really have a cause for concern. I don't have the equipment to measure it accurately and frankly don't feel like I need to. It would be interesting of course.

All the workarounds for preventing tearing in X11 come at some cost, regardless of GPU make. On my AMD GPU/KDE/Wayland machine there's no tearing at all, ever, and that's very important to me. If there's a slight increase in input lag that I cannot detect, I'm fine with that.

It's absolutely possible that powerful hardware brute-forces its way through issues that more modest machines can not avoid.

Quoting: dpanter

Quoting: kokoko3kThere has to be some input lag

I can't see it or feel it, so I don't really have a cause for concern. I don't have the equipment to measure it accurately and frankly don't feel like I need to. It would be interesting of course.

All the workarounds for preventing tearing in X11 come at some cost, regardless of GPU make. On my AMD GPU/KDE/Wayland machine there's no tearing at all, ever, and that's very important to me. If there's a slight increase in input lag that I cannot detect, I'm fine with that.

It's absolutely possible that powerful hardware brute-forces its way through issues that more modest machines can not avoid.

I hope you dont!
From your PC info i can see you're driving a 120hz panel with a 6900Xt, so you never hit the gpu limits in desktop use and your pointer and everything else is always moving in a 1/120 second.
But i can assure you that setting an higher latency in kwin because it is too heavy for your gpu (or whatever) to even maximize a window under wayland and then having hard times to move the pointer and click an icon because it lags is not a nice experience!

Also, I verified that the problem of laggy/stuttering mouse is not only dependant on kwin, as i verified it to happen in gnome-shell (which i found extremely more performant than kwin btw), and even the reference wayland compositor, weston.
https://gitlab.freedesktop.org/wayland/weston/-/issues/602#note_1322457

I can't yet say if it is not picking the hardware cursor from me, or having the cursor sincronized with the rest of the screen is a wayland "feature"

Last edited by kokoko3k on 1 April 2022 at 1:01 pm UTC

Interesting find. As a side note, my secondary monitor is portrait 1080x1920@60Hz, no lag or stutter. Don't remember any lag or stutter even on my old and terrible AMD APU laptop.