Since the upgrade to Plasma 6.6.0 it seems the overall cpu usage has gone up a bit. My fan is spinning almost constantly. Firefox uses a bit more cpu, and even plasma-system-monitor keeps using about 10-20% cpu most of the time. Anyone else who has experienced this?
I have not seen any change in idle CPU usage since the upgrade. I do find Plasma to be a bit slower, but given the added bloat, that is not surprising. I have had issues in the past that caused CPU usage to be high. Typically this was due to a driver (wifi or video). I would suggest taking a look at those two drivers and see if there is a conflict or perhaps a newer driver available.
What added bloat do you mean?
plasma-system-monitor is notoriously not optimal, neither is firefox. Monitoring resources per-application/cgroup as plasma-system-monitor does, is ironically resource hungry, regarding the network and the gpu measurements.
Neither are part of plasma per-se (system-monitor is an application), what matters is plasmashell and kwin_wayland mostly and some of its background daemon, when you speak about plasma resource usage.
Also that could be largely varying depending on your activity. And your measurement is largely un-scientific, in the perception range.
Thank you for the reply. I hope that not being scientific doesn’t exclude me from being a human or being entitled to use KDE plasma… 
Of course it is in the perception range as it is my perception… I just wondered whether others observed something similar.
Sure but your impressions don’t give them any point of comparison, it encourages others to do the same.
This could induce readers into Confirmation bias one way or the other.
Worse this can fuel some FUD regarding performance of KDE Plasma…
All the while not being at all useful to devs, while we (community developer) welcome data points.
I think there is something here, though.
It’s not directly related to the 6.6 upgrade by itself, but my system has also become extremely weird. Frequently high CPU usage and it feels like lots of things are… lagging? System Monitor is close to unusable, every app takes at last 10 seconds to start, even htop takes ~15 seconds to load. Perhaps it’s a problem with the Firefox 148 version combined with Plasma 6.6? But I’m not quite understanding it.
Leaving this comment here just to mention I’m also experiencing something strange now. I’ll try to investigate further and hopefully come with some more detailed and useful bug report.
Do you by any chance happen to use Flatpak? Are you running Firefox in Flatpak?
@meven:
I’m starting to suspect that there is a problem with KWin in 6.6 and Flatpak. Firefox, Spotify client (Electron), Godot, VLC, etc. all run in Flatpak here, and the computer really struggles with them, especially while they do anything slightly CPU intensive, if seems.
I’ll keep investigating.
I use flatpak, and have about 20 apps running on flatpak, but not firefox (mainly because the differential update doesn’t work, it always downloads almost the whole package again).
Thanks for the clarification. What kind of information would be helpful?
I just realized that plasma panel has a lag when clicking on the “start” button (or whatever that’s called). It takes about 1/2 a second to open, whereas it used to open immediately. Is that a hint?
I don’t use the default application menu but the fullscreen one (whatever it is called, my language isn’t set to English).
I have that lag when opening the launcher as well, though I’m using the Application Menu.
But here’s something you can try:
Restart and when you log back in, try using your computer without starting any of the Flatpak apps. If my hypothesis is correct, you shouldn’t experience any problems then.
Also: what kind of graphics card do you have? (Not sure if that’s important, I’m just fumbling around still). I have a laptop with an integrated AMD Radeon Graphics.
Okay, I’m very sure this is a bug now, exactly what is happening I can’t say, but as far as I can tell:
With Kwin 6.6, if any Flatpak app does any I/O (display, network, reading files, etc.) it seems there are quite a few interrupts or short locks in the main loop of Kwin.
This can cause delays in everything in the system, which can be observed in:
- laggy keyboard input or graphics (sometimes System Settings lags so I get to see the different controls on a page before the layout is applied)
- stuttering in video playback
- slow launching of applications (Application Menu, System Settings, and Discover have all been observed to be badly affected)
- Plasma itself (desktop, panels, popup windows, etc.) or any application can appear unresponsive or frozen, sometimes for up to several seconds
- high CPU utilization
- other random bugs (at one point the LSP Client in Kate only started in some of the instances I opened!)
The effects are not constant and seem to vary, but it seems that simply having a Flatpak based application running doesn’t seem to be a problem, as long as it does no IO.
I made this as a bug report: https://bugs.kde.org/show_bug.cgi?id=516721
Feel free to chime in an report if it affects you too, @HinzundKunz.
No, doesn’t help here. Even when no flatpak app is running, I still have this lag. I also experience it in other places as well (like sometimes when hitting Space-Alt to open krunner. But not always).
I have an AMD Radeon Graphics Card, too, so that might be a factor…
Things like emoji colors.