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

[retardxfce]

You invent your own theories., an example:



A property that has values auto, on and off can not be half on. Tearfree is a digital value, not analog. Wayland is garbage and will never replace X, see:
https://gitlab.freedesktop.org/wayland/wayland/issues

http://lmgtfy.com/?q=xfce+how+to+fix+screen+tearing

[oiaohm]

In gnome3, kde and some others you have tearing, but not with the Xfce desktop. The Xfce desktop is light and fast without compositing and any vsync on.

Note that when Tearfree is auto, it is off normally. See man amdgpu.

Really debianxfce you cannot read and understand.

If this option isn't set, the default value of the property is auto, which means that TearFree is on for rotated outputs, outputs with RandR transforms applied and for RandR 1.4 slave outputs, otherwise off.

Tearfree auto is half on. Heres the fun fact with xfce when screen it not rotated it sets RandR rotation of 0 what effectively means you have turns on TearFree to on because to the system the screen is rotated. Welcome to X11 stupidity.

XFCE TearFree is on unless you particularly set it off.

[aufkrawall]

Without compositor or TearFree, Xorg can only be free of tearing for fullscreen windows (because they trigger page flipping). Drag a video player window playing a juddertest video to the very top or bottom of the screen to spot the tearing in windowed mode. That has nothing to do with the chosen DE, believing otherwise is just a proof of incompetence.

That being said, I don't know why anyone should care about the tearing without compositor or TearFree. These features are there for a purpose and should function without issues (otherwise fill a bug report)...

[oiaohm]

I see only tearing when moving windows fast around the Xfce desktop. Applications work fine without compositing and scrolling in the web browser does not cause tearing. So I do not use the compositor or anything that slows down system performance.

X11 server will in fact tear with vsync on with compositor off if you drag windows fast enough because the X11 server vsync implementation is nice and buggy.. Lets just say tearing gets worse when you turn X11 vsync off as well.

Vsync total off scrolling the web browser it will from time to time tear there as well on x11 server. The fact you said it was not tearing you have left the servers vsync on..

[oiaohm]

oiaohm I just fired up AC: Unity on both Windows and Linux to check for a shadow rendering bug, and it both equally tears like hell in fullscreen without vsync.

That test shows issues just with userspace disable of vsync in form. Run X11 without a compositor with vsync off in the x11 server you will see a change for the worse. You cannot even drag basic windows around the X11 screen without them tearing in that setup let alone more fancy test. Of course that does not help the Unity test..

[aufkrawall]

oiaohm I just fired up AC: Unity on both Windows and Linux to check for a shadow rendering bug, and it both equally tears like hell in fullscreen without vsync.

[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.

[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.

[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.

[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...