[sprash]

X11 applications are able to directly render pixels on the screen via OpenGL. In Wayland those pixels are always rendered to a buffer which will then be composed on the screen.

This doesn't mean games will be "unplayable". It just means that the performance will depend on the compositor. And since the compositor also includes functionality originally provided by window managers you might get into a situation where you can't use you tiling or whatever desktop for gaming and have to switch compositors for different applications with different priorities.

Fun times...

[Crinus]

Note that Wayland introduces latency between input (you doing something) and output (seeing the result of your action), see my other posts for detail. While this latency wont make a game unplayable, it will make the experience worse for fast paced games (especially games where you control the camera directly with the mouse). However this is an issue if you are running a game in a window, the compositor should get out of the way when running fullscreen (or at least i hope it does, but that is the same with X11, some compositors see a fullscreen window and consider it perfectly fine to keep going on).

[chousuke]

Do you actually have benchmarks and evidence showing that Wayland introduces latency over X11, or is it just a guess based on how you think Wayland works?

I mean, sure it might in some cases where you can use X11 to "directly" draw stuff on the screen, but most games would be double-buffering or triple-buffering anyway. I don't really see why Wayland would add any latency there, considering all the compositing is going to happen on the GPU anyway.

[Crinus]

See my other posts where i explain why that would be the issue as well as how it could be addressed, but that would require hardware that AFAIK doesn't exist.

I do not have any benchmark as the only way i can think of for performing a proper benchmark that measures input-to-output latency would be using something like rigging a mouse to a robotic hand (or something like that) and capturing the screen output with a very high speed (e.g. 1000fps) camera. Sadly i do not have the necessary equipment for doing that.