I've updated to Plasma 5.4 on my Arch Linux, but now I have the problem that plasmashell will constantly consume exactly 17% CPU (I guess across all CPU cores, it's a quad core i5, no HT). Killing plasmashell and restarting it helps temporary, but the problem appears again after around 5-15 minutes. I've not figured out yet what action triggers this problem, but it seems to happen randomly after some time. I've also tried to remove all widgets (except the essential ones, like NM, KMixer, clock...)

Is this a known issue? Any idea where I could look at? Let me know if you need any log files (I'm not sure what might be useful in this case, at least dmesg didn't show up anything relevant)

Thanks!

Can you confirm you're not using any plotter widget (CPU, network....)?

I think I know what is causing this problem, it seems to be the new "Application Dashboard". I started this computer ~2 hours ago and plasmashell was at normal levels. Simply opening the app dashboard and scrolling through the menus with the mouse reproduces this issue every time for me. Then plasmashell consumes 17% CPU even when the dashboard is "closed".

Edit: I'm using the CPU load widget in my panel, but even with it removed the problem persists.

Please file a bug on bugs.kde.org with details on the problem and your hardware configuration.