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

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

#41

Post by 0x457 »

Aurornis wrote: post #36
hs86 wrote: post #22

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 be…

Many PC games have dynamic resolution, too. The reason consoles target 60fps is because that’s the frame rate you get with most TVs and everyone playing the game has the same hardware (or couple variants). > 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…

Consoles target 30fps though. Very rarely they target 60fps and even less rarely they can reach that.

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

#42

Post by retatop »

cgyvbunji wrote: post #3

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.

Isn't Wayland always one frame delayed compared to Xorg to avoid tearing or has that been changed? If so, his very high refresh rate would minimize that effect

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

#43

Post by torginus »

NelsonMinar wrote: post #15

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…

This kind of thing is certainly possible under Windows - you can basically patch any kernel API call, replace any COM object instantiation, install filter drivers that intercept any request to and from a device, replace userland DLLs with your own.

It's really scary what you can do, to the point that I often asked myself 'why allow this?' - seeing as hits on certain APIs took me to blackhat forums and articles about writing exploits.

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

#44

Post by Aurornis »

cgyvbunji wrote: post #3

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.

> and noticed that significant lag

Only xwayland showed that result. The difference was only a couple milliseconds. That’s in the range where I start to doubt that people are feeling the latency difference. If it was 10-20ms I could believe it, but not when it’s a couple milliseconds.

The author of this post did a good job of getting all of the other confounding settings out of the way. It’s possible that the people complaining that Wayland was slow were starting from an unoptimized situation and as part of switching to some low latency variant they set all the correct settings.

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

#46

Post by im3w1l »

tfrancisl wrote: post #17
bigyabai wrote: post #8

Earlier quoted context omitted.

AMD's Mesa drivers are better, but if you already have an Nvidia card then you can still use it just fine with Wayland. The biggest hit is Vulkan performance (~20% less than Windows iirc) but for desktop and casual gaming use, Nvidia's proprietary drivers are perfectly fine.

Seconding this. I'm not happy with the fact that the drivers are proprietary, I really prefer FOSS. But, I am tired of having to deal with FUD around performance and issues with NVIDIA devices which simply don't exist at scale. I have friends who are stuck on Windows not because they play games with Windows-only anticheat, but because theyve been told by GNU heads that NVIDIA drivers simply don't perform acceptably o…

Firefox is software rendered on linux-nvidia which leads to a bizarre situation of simple web animations lagging on decent computers.

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

#48

Post by 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.

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

#50

Post by Hikikomori »

NelsonMinar wrote: post #15

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…

Not Microsoft but Battlenonsense investigations on latency did get Nvidia to create reflex.
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