Measuring Input Latency on Linux: X11 vs. Wayland, VRR, and DXVK

overtone1000

This is why I read Hacker News. Thank you.

cgyvbunji

He seems confused at the end why people think wayland is so slow, but don't you think it's because of his xwayland result? People were probably running x11 games on wayland and noticed that significant lag. Just a wild guess. Very nice article, wish people did actual measurements like this more often, of all sorts of things.

hparadiz

Amazing work. Thank you for putting this together.

shmerl

> A lot of people still use X11 over Wayland because Wayland is said to have much worse input lag Wayland is fine. People should use AMD and KDE Plasma. I'd avoid Nvidia to begin with.

PcChip

I saw a very similar post a month or two ago, is this the same author? edit: no, this is the one I was remembering: https://farnoy.dev/posts/linux-latency

stusmall

Great article! Thank you. Also in case others walked away with the same question I had, I'll save you the googling: use the utility vrrtest to help validate if VRR is properly configured on your machine.

esseph

From the "Similar Efforts" section toward the bottom: --- David Ramiro built his m2p-latency and compared X11 vs Wayland in his article Building an Input Latency Meter (Because ‘Wayland Feels Off’ Isn’t a Metric) as well, coming to similar conclusions: Native Wayland is on par with native X11 (all tied at ~7 ms), while XWayland roughly doubled the latency in his tests. farnoy did extensive testing with the Open-Source-LDAT in his post Linux latency measurements and compositor tuning, also concluding that XWayland should be avoided.

prhn

Awesome article. I switched my daily driver / gaming rig to Fedora a few months back. Everything seems snappier compared to Windows, but not sure if it’s in my head, and I’ve been very curious about gaming input latency. This helps answer some questions. I recently switched to hyprland and I’m very interested how that fits in these results. hyprland uses Wayland so I hope the author might revisit now that hyprland is gaining in popularity. I’ve considered using gamescope to hopefully get in front of some of these concerns, but I’m on nvidia and there is some discussion about it not working well there. Now the author's got me thinking about gaming-optimized kernels, which I did not realize was a thing. I play competitive fighting games so input latency is a huge concern. Would love to hear from anyone else who’s been down this path.

seba_dos1

There's no such thing as "Wayland input latency". It's just a word salad, akin to "HTTP animation smoothness". The post is measuring Xorg vs. KWin (and also XWayland), other implementations of either X11 or Wayland will have different characteristics. I wonder where the XWayland's added latency comes from though, it seems suspiciously high to just be easily hand-waved as overhead.

modeless

This is awesome. I would like to see tests like this done at 60 Hz as well, and also with non-3D apps. I suspect the results might look different in those conditions. A 500 Hz monitor is not the common case. 2ms is a whole frame!

NelsonMinar

One thing that's lovely about Linux is this kind of analysis is not only possible, but meaningful. These results will get reported back to the graphics software authors and the distribution packagers and the ecosystem will improve. There's no sense with Microsoft that kind of improvement is possible. I recently switched to Linux after years on Windows desktop, mostly because the KDE Plasma desktop feels snappier than Windows 11. Also the feeling that if something isn't working right I can probably tinker and improve it. It's been really nice. If you haven't tried Linux desktops in awhile give Bazzite a whirl: it's a Fedora customized for gaming. Even if you don't game it's an easy way to get a very functional Linux desktop in no time at all.

calvinmorrison

X11 is a protocol. Xorg is an end of life'd project run by the Wayland team. Xlibre is an actively developed and maintained X11 protocol display server. Xfree86 is dead, long live Xorg. Xorg is dead, long live Xlibre!

dreamlayers

Why isn't Wayland better than X11?

hs86

It looks like consoles and PCs have settled on somewhat different gaming configurations. Consoles usually try to target a fixed output frame rate, while the resolution is often dynamic. On PCs, by contrast, the resolution stays static, while the frame rate and frame-time pacing are dynamic. How does this fit into the latency discussion? Especially in competitive gaming, I often see people targeting frame rates way beyond their display’s refresh rate. I’m not sure whether this actually provides a real benefit or whether they’re chasing a placebo effect. Am I out of touch, or is it the children with colored LEDs on their DRAM sticks who are wrong?

bsimpson

The Rock Band guitars have a photoresistor for precisely this purpose: the screen flashes and the guitar responds when the light hits it. It helps make the otherwise very painful calibration process transparent. It would be so cool to get that to work in Linux. I know the instrument code is in hid-sony. Here are some open tabs I've got in case anyone's curious: - https://pascal.giard.info/techreports/nguyen-daniel-autocali... - https://www.niangames.com/articles/reverse-engineering-rockb... - https://github.com/torvalds/linux/blob/master/drivers/hid/hi...

Telaneo

I have a vague memory of (X?)Wayland being much worse than X11 before, and some patch or protocol making it out to all the relevant implementations, but I might have imagined that, since these result show virtually no difference, and only XWayland shows a marginal difference. Or maybe it just came out of nowhere and was never true.

haunter

SteamOS and Bazzite both use Xwayland through gamescope which is the worst option as it seems https://github.com/ValveSoftware/gamescope >Avoid XWayland. It added 3.13 ms of latency, more than all other effects combined.

clodecloud

Linux is underrated and is only getting better. I am building a linux cloud platform so we can build unity and Godot games with mcps right in your browser. Not only is Linux the only option but I have realized it is the best option for AI

Havoc

Using Wayland (hyprland) for daily driver and it's the happiest I've been with an OS in a long time on feel. Feels crisp in that spartan way that windows & macos just don't - no animations, taskbar, popups or god knows what else.

Aurornis

This used a 500Hz display which hides a lot of the problems that would show up on slower displays. The XWayland result is 3ms slower, which at refresh rates this high makes me wonder if it was one frame behind. Running the tests at 120Hz or even 60Hz might be more interesting because we could start to separate out very small differences in timing from the much larger effects of being a full frame behind.