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.
NelsonMinar
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.
prhn
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.
Aurornis
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.
cgyvbunji
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.
seba_dos1
Been dealing with this a bit at Breaka Club. We teach kids to code with a modded version of Overcooked 2!.
We stream OC2[1] with our mod preinstalled over WebRTC. This ensures that kids/schools don't have to try and install the mod. This is particularly important since we support running on school provided hardware. Installing a game without a mod would be hard enough. Added advantage though is kids play with a virtual (on screen) gamepad on iPads in Mobile Safari.
Game instances run in Docker containers in Kubernetes/k3s atop very outdated nVidia hardware. Given we're already going across the Internet into school networks, we've tried very hard to optimize latency across the board. Using NVidia NVEnc with DMABuf (zero copy) etc. We're unfortunately using XWayland at present so experience the documented input overhead. Although our inputs are virtual devices at this point, so the overhead may be a bit different. Trying to optimize this whole thing end to end has been a challenge. I would say that performance is currently "acceptable".
[1] We've bought a limited number of copies of OC2 and pods claim a license on startup. If we're at capacity, kids play something else.
Benjamin_Dobell
I am not super familiar with Wayland, but basically how composited rendering under X11 works, is if you have a fullscreen window, you can give an 'unredirect' hint to the compositor, in which case when nothing else is drawing your screen, it will stop compositing, and pass your app's swapchain directly to the screen.
This is pretty much optimal, and you can't really do much better than this.
Once a stray window appears on top, or something makes the compositor think it can't do this, it'll do the intermediate step of compositing your app window with others into a temp buffer, and render that.
Sometimes the unredirect breaks for some reason (I remember a case where for some inexplicable reason my app kept creating a window 1px smaller than the screen height), or you use XWayland, you get bad latency.
Since this is a fundamental constraint, other compositors on different OSes must work like this, and you can run into issues like this as well.
Another thing - Wayland afaik started exporing 'display planes' - which are a HW feature of GPUs, that allow it to composite multiple layers together - which means the game can render at full FPS and all the windows on top will be drawn into a different plane and get composited with no ill effects - not sure if this is actually used in production yet.
torginus
Something interesting is the author right away wants to isolate and reduce placebo. But surely, latency is all about "placebo" and "vibes" and "feel" is it not? The ultimate test is how it feels to use on a personal level.
Of course, where gathering this sort of data _is_ useful is diagnosing and fixing real latency so it obviously has merit. I just think it's ok to lean on taste and experience for most things UI/UX, including latency.
Another point, by couching the comparison in a less technical form (for example, rating a configuration/setup out of 5 stars or some similar approach), it protects from being "too methodological" during testing and data-gathering. One possible issue with the author's methods is if there are degenerative cases that are common in the day-to-day experience of a given configuration, they are unlikely to be present during the precise test that they have setup.
url00
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?
hs86
Addressing all the people here talking about latency of under 10ms, I direct you towards these:
comments (10)
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.
NelsonMinar
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.
prhn
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.
Aurornis
cgyvbunji
I wonder where the XWayland's added latency comes from though, it seems suspiciously high to just be easily hand-waved as overhead.
seba_dos1
We stream OC2[1] with our mod preinstalled over WebRTC. This ensures that kids/schools don't have to try and install the mod. This is particularly important since we support running on school provided hardware. Installing a game without a mod would be hard enough. Added advantage though is kids play with a virtual (on screen) gamepad on iPads in Mobile Safari.
Game instances run in Docker containers in Kubernetes/k3s atop very outdated nVidia hardware. Given we're already going across the Internet into school networks, we've tried very hard to optimize latency across the board. Using NVidia NVEnc with DMABuf (zero copy) etc. We're unfortunately using XWayland at present so experience the documented input overhead. Although our inputs are virtual devices at this point, so the overhead may be a bit different. Trying to optimize this whole thing end to end has been a challenge. I would say that performance is currently "acceptable".
OC2 coding: https://www.youtube.com/watch?v=ITWSL5lTLig (not streamed in this case)
[1] We've bought a limited number of copies of OC2 and pods claim a license on startup. If we're at capacity, kids play something else.
Benjamin_Dobell
This is pretty much optimal, and you can't really do much better than this.
Once a stray window appears on top, or something makes the compositor think it can't do this, it'll do the intermediate step of compositing your app window with others into a temp buffer, and render that.
Sometimes the unredirect breaks for some reason (I remember a case where for some inexplicable reason my app kept creating a window 1px smaller than the screen height), or you use XWayland, you get bad latency.
Since this is a fundamental constraint, other compositors on different OSes must work like this, and you can run into issues like this as well.
Another thing - Wayland afaik started exporing 'display planes' - which are a HW feature of GPUs, that allow it to composite multiple layers together - which means the game can render at full FPS and all the windows on top will be drawn into a different plane and get composited with no ill effects - not sure if this is actually used in production yet.
torginus
Of course, where gathering this sort of data _is_ useful is diagnosing and fixing real latency so it obviously has merit. I just think it's ok to lean on taste and experience for most things UI/UX, including latency.
Another point, by couching the comparison in a less technical form (for example, rating a configuration/setup out of 5 stars or some similar approach), it protects from being "too methodological" during testing and data-gathering. One possible issue with the author's methods is if there are degenerative cases that are common in the day-to-day experience of a given configuration, they are unlikely to be present during the precise test that they have setup.
url00
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?
hs86
https://www.youtube.com/watch?v=vOvQCPLkPt4
https://www.youtube.com/watch?v=fE-P_7-YiVM
https://news.ycombinator.com/item?id=42832155
coldblues