The situation on KDE/Kwin/Plasma performance

Okay, so, it seems the situation evolved meanwhile. I would like to express my warmest thank you to the Nvidia team as it was a major one.

One long standing and very annoying was apparently fixed, see : https://www.gamingonlinux.com/articles/nvidia-pushed-out-two-new-linux-drivers-recently-with-39645-and-39077.12184

“Fixed a bug that caused kwin OpenGL compositing to crash when launching certain OpenGL applications.”

I yet have to test in the long run but it seems the most annoying issue occuring with NVIDIA drivers & Kwin was fixed, that is to say : the panel / desktop freezing randomly when an app would interrupt and resume kwin compositing (they would still react to mouse clicks but wouldn’t update). It would be great if the NVIDIA team could get in touch with the kwin team (whose leader stepped down meanwhile) to tell them what was triggering it…

I still have the following problems with either no solution or requiring a work-around :

  • sub-optimal framerate on the desktop (occurs under GNOME too, but doesn’t occur with open source drivers (Nouveau, AMDGPU, Intel…).
  • work-around to get a tear-free experience (either : triple buffer ; GL_YIELD ; or force compositing pipeline). Not required either when using open source drivers. Also partly necessary under GNOME.

(also, applying “force compo pipeline” slows down a lot KDE startup, but maybe the problem is on KDE’s side this time !)

Cheers ! Thanks for caring for KDE users !

Actually, it does not seems so:
https://bugs.kde.org/show_bug.cgi?id=353983#c142
Is it still “fixed” for you?
If the answer is yes, maybe you could write your findings to the readers of that bug report.

@kokoko3k :

Well, there are improvements apparently.

Yes, the panel still freezes once in a while when compositing is interrupted. (started game, generally)

That’s a little annoying if you alt-tab to the desktop. But at least, the panel is restored when the game is exited.

In my experience, in the past, the big problem was that the panel would sometimes remain in this frozen state after then game had exited. (had to restart plasmashell which is not acceptable for normal users – yep I did install Neon onto some family PCs :)

So it’s half fixed…

OFF TOPIC : meanwhile, I gave GNOME another try (Manjaro & Ubuntu). I was surprised to realize :

  1. Gnome Shell would eat tons of CPU usage when just scrolling in Firefox. Animations are quite jerky (worse than in kwin actually !). Even with a non nvidia card they are not constantly smooth contrary to kwin (but cpu usage is normal with open source drivers). It’s apparently being optimized at the moment.
  2. you also need the tearing workaround under GNOME (to a lesser extent, but still).

So there are clearly issues on both major desktops with the NVIDIA drivers, which is sad to see as gaming performance is stellar and those cards are great (power efficiency). I really wonder why this situation remains after all those years, that’s strange.

Edit : double post

Hi !

Just checking if some people here had had better experience meanwhile ?

On the Arch wiki, there’s a slightly different solution
https://wiki.archlinux.org/index.php/NVIDIA/Troubleshooting#1._GL_threads
(applying USLEEP to kwin only).

I made several other attempts with different DEs meanwhile : (with my 1060 GTX and different drivers versions ranging from 390.x to 415.x)

  • I had very disappointing experience with the latest Gnome 3.30 (a lot of stuttering all the time on the desktop – especially terrible under Ubuntu 18.10 when used along with FF with hardware acceleration : 50% of the time, the FF scrolling is randomly very jerky for the very same pages. Some kind of sync issue I guess. I double checked under Manjaro – not great either.

  • I had a surprisingly GOOD experience with Cinnamon 3.8. The desktop feels constantly smooth. Even FF seems to suffer less than with the other DEs (in which for instance the “new tab” animation is not perfectly smooth).

  • Regardless of the DE used, some apps are always slower : i.e. scrolling in FF or in the Steam client in thumbnails mode.

  • With all DEs EXCEPT CINNAMON I have a significantly smoother desktop when using OSS drivers, Intel / AMD GPUs. (well, some cinnamon apps are intrinsically slower thank KDE ones but at least windows animations / Muffin is butter smooth).

AND UNDER KDE

  • Well, the framerate gets very frequently under 60 when moving windows & triggering effects. That’s really OK for most people I guess – but that’s not normal.
  • As soon as there is some significant CPU usage, apps / animations seems to stall. If you’re playing a video and starting a big app, the picture will freeze a little – which never happens with OSS drivers.
  • Just opening Dolphin and browsing feels a little bit sluggish. That’s not placebo but maybe a little subtle. Things that feel really instant with other GPUs are not when using the NVIDIA driver. As I said before it’s OK but frustrating when you have a great GPU.

–> when using Intel / AMD GPUs with OSS drivers, I get a constant 60 FPS framerate REGARDLESS OF the CPU usage. I never get a single app to “stall” under high CPU usage. Every app feels more responsive. <–

  • Also I noticed that when using “force compo pipeline” along with disabling VSYNC (in KWIN and in some games) I would frequently get no tearing and, it seems, less input lag. That’s especially noticeable in some games, like Hollow Knight. So it seems to be a good solution although I’m not sure what is optimal.

So well. It’s definitely usable. But it definitely make you feel you have a slower machine. I heard NVIDIA sent some cards to some KWin devs. I hope the situation will change, eventually ! :-)

I can confirm very slow Plasma responsiveness and jittery cursor with a GeForce GT 710 on a very fast machine, with both the recent short- and long-term Nvidia drivers. It doesn’t matter what the resolution is or what the refresh rate is set at, the Application Launcher menu, for example, takes 1-2 seconds to pop up, and I have all desktop effects off!

Firefox, however, renders fast, but menus etc. pop up just as slowly.

And Plasma with the VESA driver is fast.

It’s some combination of Plasma with the Nvidia drivers that seems to be causing the slowdown.

The tricks mentioned in this thread don’t help.

I’m using KDE Plasma 5.14.4.