Has implications for competitive FPS gaming on modern Linux — one more problem to fix. For example "The Finals" allows Linux players, but imagine having this much input delay and having to revert to classic x11 to play games, lol.
I haven't tried any games that use a cursor with Wayland yet so I don't know if it would have an impact there.
I think it has to do with whether or not the game in question is reading the mouse device directly (e.g. through SSL) or via the compositor. If it's reading the device directly it stands to reason that there would be less latency.
That has not been proven in the article. Input handling follows different paths for full screen games.
It would be more of a problem the other way around, if we had to resort to Wayland to get low latency. I think most of us using Linux for gaming and casual stuff are happy to stick to X11 for now and the foreseeable future. It has good support in software, its failure modes are well-documented, and it doesn't add one more layer to the pile of complexity that desktop linux already is; at least, not one us users have to consciously keep in mind as a common source of issues.
https://github.com/ValveSoftware/csgo-osx-linux/issues/3856
From outside it's hard to tell if it's truly protocol differences or just the age of the implementations on X11, but when Wayland came out every project has claimed improvements over the old X11 stack. Also, from the early Wayland days presentations bashed the protocol as something that couldn't be fixed without a rework that was not going to happen due to the dead weight of backwards compatibility and awful older hardware.
As a user applications running on Wayland have consistently improved on how nice things feel if you don't miss your latency deadlines. It's easy to perceive on apps, and straight out obvious in games.
Suppose two players notice each other at the same time (e.g. as would naturally happen when walking around a corner in a shooter), first to shoot wins, and their total latencies are identical Gaussians with a standard deviation of 100ms. Then a 6.5ms reduction in latency is worth an additional 2.5% chance of winning the trade. Maybe you won't notice this on a moment by moment basis, but take statistics and its impact should be measurable.
In ELO terms a 2.5% gain in win rate is around a 10 point increase (simplifying by assuming that single Gaussian is the entire game). That's small, but if you were a hardcore player and all it took to raise your ELO by 10 points was using a better monitor/mouse/OS... why not? Doing that is cheap compared to the time investment required to improve your ELO another 10 points with practice (unless you're just starting).
Also, I think you'd be surprised what people can perceive in a context where they are practiced. Speed runners hit frame perfect tricks in 60FPS games. That's not reaction time but it does intimately involve consistent control latency between practice and execution.
> Suppose two players notice each other at the same time (e.g. as would naturally happen when walking around a corner in a shooter)
This is not true for third person games. Depending on a left sided or right sided peek and your angle or approach, players see asymmetrically.
For example, Fortnite is a right side peek game. Peeking right is safer than peeking left as less of your body is exposed before your camera turns the corner.
I believe distance also plays a part in the angles.
> “I was working with Larry Mullen, Jr., on one of the U2 albums,” Eno told me. “ ‘All That You Don’t Leave Behind,’ or whatever it’s called.” Mullen was playing drums over a recording of the band and a click track—a computer-generated beat that was meant to keep all the overdubbed parts in synch. In this case, however, Mullen thought that the click track was slightly off: it was a fraction of a beat behind the rest of the band. “I said, ‘No, that can’t be so, Larry,’ ” Eno recalled. “ ‘We’ve all worked to that track, so it must be right.’ But he said, ‘Sorry, I just can’t play to it.’ ”
> Eno eventually adjusted the click to Mullen’s satisfaction, but he was just humoring him. It was only later, after the drummer had left, that Eno checked the original track again and realized that Mullen was right: the click was off by six milliseconds. “The thing is,” Eno told me, “when we were adjusting it I once had it two milliseconds to the wrong side of the beat, and he said, ‘No, you’ve got to come back a bit.’ Which I think is absolutely staggering.”
I didn’t think it was. But it is. I promise!
It’s not necessarily a reaction-time game-winning thing. It’s a feel.
With virtual instruments, my experience is that when you get down to ~3ms you don’t notice the latency anymore… but!, when you go below 3ms, it starts feeling more physically real.