KWin-LowLatency: An Effort To Yield Less Stutter & Lower Latency With The KDE Desktop

[royce]

More importantly, you won't be driving acceptably mixed dpi display scenarios out of X11. 4k is relatively rare now, but it is gaining ground same as 1080p has done.

[czz0]

Speak for yourself. Even though my gaming PC uses X11, I deliberately keep vsync on because I prefer a tear-free experience over input latency. Sure, a hard cap of 60Hz is dumb (assuming your display goes higher) and I agree there should be a [user-friendly] way to disable vsync, but you are heavily exaggerating your preferences as though they're what everyone else prefers.

I explicitly was talking about gaming, so stop with the strawman argument of Vsync for desktop usage which I said nothing about.

Vsync off for fast pace games is not just my preference, it is horrible for any FPS or fast paced game, literally 100% of any professional competitive FPS players, and the vast majority of any regular competitive FPS players, have Vsync off.

No one with a brain will tell you Vsync is okay to have enabled for a game like CSGO or Overwatch.

[oiaohm]

Vsync off for fast pace games is not just my preference, it is horrible for any FPS or fast paced game, literally 100% of any professional competitive FPS players, and the vast majority of any regular competitive FPS players, have Vsync off..

This is a lie because there are two different forms of vsync disable. Even when you turn off vsync on Windows or OS X the buffer to screen is still processed to screen by vsync. The opengl library lies to application and say start rendering next frame instead of waiting for the vsync window.

When you disable vsync on X11 server you do something major worse. You disable vsync in the present code so you get tearing from hell.

You don't want option to turn off vsync in the compositor. You want option to lie to application so it does not wait for a vsync before starting to render stuff but this is really a opengl quirk flag.

Basically you don't want Vsync blanket off as this is half rendered buffers being displayed to users and fairly much make you not be able to see players lining up to attack you in FPS.

Pro players in fact want vsync half off.

[czz0]

This is a lie because there are two different forms of vsync disable. Even when you turn off vsync on Windows or OS X the buffer to screen is still processed to screen by vsync. The opengl library lies to application and say start rendering next frame instead of waiting for the vsync window.

When you disable vsync on X11 server you do something major worse. You disable vsync in the present code so you get tearing from hell.

You don't want option to turn off vsync in the compositor. You want option to lie to application so it does not wait for a vsync before starting to render stuff but this is really a opengl quirk flag.

Basically you don't want Vsync blanket off as this is half rendered buffers being displayed to users and fairly much make you not be able to see players lining up to attack you in FPS.

Pro players in fact want vsync half off.

You want Vsync completely disabled all the way through, on Windows or Linux.

You do not want Vsync disabled in the game, but still running through a desktop compositor with Vsync

It's true that Vsync is force enabled for Windows 10 with no way to disable, but fullscreen games are supposed to fully bypass the compositor, just like Gnome is supposed to do.

Tearing is infinitely better than Vsync input lag for competitive FPS games.

Professional CSGO players use 240Hz or 144Hz monitors and do not care about tearing which is almost unnoticeable at that refresh rate anyway.

[oiaohm]

It's true that Vsync is force enabled for Windows 10 with no way to disable, but fullscreen games are supposed to fully bypass the compositor, just like Gnome is supposed to do.

Try again. Vsync enabled was in fact forced in Windows since windows 3.5 with the in kernel graphic solution.

If you think you have turned Vsync off under windows you have in fact failed. Windows 10 removed the bogus in fact do nothing vsync option.

Professional CSGO players use 240Hz or 144Hz monitors and do not care about tearing which is almost unnoticeable at that refresh rate anyway.

Tearing is a lot worse than you think. Even at 240HZ proper tearing of rendering a no ready buffer multi times over is still absolute horrible.

You want Vsync completely disabled all the way through, on Windows or Linux.

You are only saying this because you are not aware that no matter what you do on Windows you are not turn off the vsync option enabled by the NT kernel.

Last time you could in fact run on windows with Vsync fully off was Windows Me the last of the 9x series.

Be very careful what you are asking for that is really what you want. Min Vsync is smart this buffer is half done and not ready skip it display last fully complete buffer when line up for vsync. Applications don't really need to know this is going on. You do not ever want Vsync complete off.

[aksdb]

Wrong. The majority uses Mesa drivers and KWin on Wayland works just fine with them. There are a few regressions but far from "completely broken".

Interesting. I tried it with Mesa drivers and get black borders around windows, some tray icons not showing properly and some applications outright crashing.
So for me it is still a no-go, while it works fine on X11.

[schmidtbag]

I explicitly was talking about gaming, so stop with the strawman argument of Vsync for desktop usage which I said nothing about.

Actually, so was I. So if you're going to use logical fallacies, how about don't accuse me of one I actually didn't do?

No one with a brain will tell you Vsync is okay to have enabled for a game like CSGO or Overwatch.

And everyone plays CSGO or Overwatch? Look who is strawmanning now...

[aufkrawall]

Where do these idiotic ideas originate from?
Nothing has changed with Windows 10 in terms of vsync, except of some limitations of UWP games with upscaling/downscaling.

[b15hop]

I agree with the comments of several others, ideally we need to get a low latency Kwin based on Wayland and Vulkan.

I love the idea of Vulkan, but I agree that it's a mountain of new technology to learn.

My issue with kWin is more along the lines of microstutter and slightly high cpu overhead. I use a 780gtx and binary blob driver. All 4 cores seem to be used just sitting there but admit that it's not always kWin chewing up cpu. I think it's some KDE index daemon which eventually settles down given enough time. I also use a HD video background which I am sure doesn't help much either. kWin has to be one of the nicest looking desktop environments. If those two issues were fixed, it would be near perfect.

[oiaohm]

Where do these idiotic ideas originate from?
Nothing has changed with Windows 10 in terms of vsync, except of some limitations of UWP games with upscaling/downscaling.

There is one change adding the registry key to turn vsync full off of under 9x/Me under windows 10 gets auto deleted. Its not like that registry key has been doing anything it was never connected up in 2000 forwards todo anything so it just sat wasting registry space. People have been turning it on and claiming differences for ages and it basically been a placebo effect. Its like how people for a long time would mess with Linux kernel nice settings on processes and claim differences before it was even hooked up.

The fact that windows only party turns vsync limitations off gamers have not complained about. Only party turning of massively reduces tearing by not displaying part ready buffers.