Bug 351448

Summary: The plasmashell starts to eat CPU power
Product: [Plasma] plasmashell Reporter: Andreas Schneider <asn>
Component: Desktop ContainmentAssignee: Sebastian Kügler <sebas>
Status: RESOLVED DUPLICATE    
Severity: normal CC: 2Kmm, jm.ouwerkerk, kde, kde, mkotl
Priority: NOR    
Version: 5.3.2   
Target Milestone: 1.0   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Attachments: plasmashell process strace
Screenshot of the issue
plasma-org.kde.plasma.desktop-appletsrc

Description Andreas Schneider 2015-08-18 14:27:51 UTC
Hi,

plasmashell process started to need ~15 percent of my cpu time which is more than one core. I do not know what caused it, but it spins on a futex. strace will folllow

Reproducible: Sometimes
Comment 1 Andreas Schneider 2015-08-18 14:29:11 UTC
Created attachment 94094 [details]
plasmashell process strace

This is a short strace capture of the plasmashell process which needed 100% of one cpu core ...
Comment 2 Andreas Schneider 2015-08-18 14:30:28 UTC
I do not have a CPU widget running ...
Comment 3 jm.ouwerkerk 2015-09-16 15:20:11 UTC
Can confirm: seems to be caused by hovering over something that provides a tooltip. For example the clipboard. Or a battery monitor.

If you taunt the shell a bit like this, it will also cause the plasma panel to start flickering.
Comment 4 jm.ouwerkerk 2015-09-16 15:23:36 UTC
Created attachment 94603 [details]
Screenshot of the issue

Displays ksysguard CPU monitor while hovering over the clipboard icon in the systray.
Comment 5 David Edmundson 2015-10-28 14:30:59 UTC
Please attach your .config/plasma-org.kde.plasma.desktop-appletsrc
Comment 6 Andreas Schneider 2015-10-29 11:14:18 UTC
Created attachment 95207 [details]
plasma-org.kde.plasma.desktop-appletsrc
Comment 7 Andreas Schneider 2015-10-29 11:16:20 UTC
Attached the requested file. It isn't a widget which is causing that ...
Comment 8 Manuel Mommertz 2015-11-18 11:41:14 UTC
Same problem here. I've tried debugging but I'm out of ideas how to proceed further.
What I found so far:
* top reports currently 76% cpu usage for plasmashell and 35% for X
* sysprof cannot pinpoint the exact function which causes the high load (no map) but the kernel is doing a lot of copying. So I think plasmashell is repeatedly repainting something.
* as comment 3 said it seems related to hovering: if I hover some task it often happens that other windows stay transparent after the mouse leaves the entry. I have to re-hover-and-leave the entry (sometimes a few times) to see all windows again.

Let me know if I can do anything to help solving this problem (testing patches, running some kind of debug-sofware).
Comment 9 Maciej Kotliński 2016-08-26 07:43:05 UTC
Same here. The problem exists from longer time. It is making KDE less responsible (scrolling, moving windows, etc.).
Comment 10 David Edmundson 2016-08-26 16:11:25 UTC

*** This bug has been marked as a duplicate of bug 356479 ***