plasmashell is eating 100% cpu and all UI is slow

[DimanNe]

plasmashell (and Xorg) processes have recently started to eat 100% cpu and all UI operations are VERY slow now.

Some info from perf top:

Annotate _Z7qstrcmpRK10QByteArrayPKc
Zoom into plasmashell(2412) thread
Zoom into libQt5Core.so.5.5.1 DSO
Browse map details
Run scripts for samples of thread [plasmashell]
Run scripts for samples of symbol [_Z7qstrcmpRK10QByteArrayPKc]

Plasmashell thread
http://pastebin.com/CZtfCq7m

Xorg thread
http://pastebin.com/eAi9Ua9N

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: plasma-workspace 4:5.5.5.2-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-24.43-generic 4.4.10
Uname: Linux 4.4.0-24-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: KDE
Date: Wed Jun 15 09:50:25 2016
InstallationDate: Installed on 2012-11-28 (1294 days ago)
InstallationMedia: Kubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.1)
JournalErrors:
 Error: command ['journalctl', '-b', '--priority=warning', '--lines=1000'] failed with exit code 1: Hint: You are currently not seeing messages from other users and the system.
       Users in the 'systemd-journal' group can see all messages. Pass -q to
       turn off this notice.
 No journal files were opened due to insufficient permissions.
SourcePackage: plasma-workspace
UpgradeStatus: Upgraded to xenial on 2016-04-22 (53 days ago)

[DimanNe (dimanne)]

I notice, it starts to happen when psi icon (in tray) is blinking.
(But it also happens without running psi. So psi icon in tray is not the only cause of this bug)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Carl Nobile (cnobile1)]

This is definitely an issue on 16.04. If I kill plasmashell and restart it again the problem go away for about 6 hours then slowly returns.

[WitherSlick (witherslick)]

Definitely affects me as well, although I'm on mint 18.1 running KDE. I have to restart plasmashell at least twice daily to keep it responsive. However this command solves all my issues temporarily: "kquitapp5 plasmashell && kstart plasmashell"

I'd just like to know the cause of this issue, as it really shouldn't happen in a "desktop ready" OS.

[Christian Treczoks (ch.treczoks)]

Just updated to Kubuntu 17.4, and plasmashell is an epic disaster. On first boot, plasmashell ate 21 cpu minutes(!) before it became halfway responsive, but failed to render about half the letters in the system tray as well as in the startup menu. I killed and restared plasmashell, and it "only" ate 7 cpu minutes. All while running at 80+% cpu usage.

I have already killed bluetooth service, but this did not really make a difference.

And yes, plasmashell has always been a cpu hog, from 14.4 over 16.4, but at the moment, it is intolerable. WTF is this program doing there, burning CPU cycles for no apparent reasons? Did someone include a bitcoin miner for the kubuntu project into the startup? ;-)

As I have no idea what kind of information you need to debug this, just tell me what and how to get it, and I will provide. I want this issue gone for good. And it looks as if I'm not alone...

[vasilisc (vasilisc)]

plasmashell consumes 100% CPU and rendering programs becomes slow.
-----------
Thu, 27 Feb 2020 09:02:03 +0300
[Ubuntu]
Description: Ubuntu Focal Fossa (development branch)
Release: 20.04

[Kernel linux]
Linux vasilisc 5.4.0-14-generic #17-Ubuntu SMP Thu Feb 6 22:47:59 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

[Kernel command line]
BOOT_IMAGE=/vmlinuz-5.4.0-14-generic root=UUID=6d8ea6da-b2d9-406c-a812-2b21a2925731 ro rootflags=subvol=@ elevator=noop

[VGA]
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GK107 [GeForce GT 640] [10de:0fc1] (rev a1) (prog-if 00 [VGA controller])
        Subsystem: ASUSTeK Computer Inc. GK107 [GeForce GT 640] [1043:83f3]
        Flags: bus master, fast devsel, latency 0, IRQ 33
        Memory at f6000000 (32-bit, non-prefetchable) [size=16M]
        Memory at e0000000 (64-bit, prefetchable) [size=256M]
        Memory at f0000000 (64-bit, prefetchable) [size=32M]
        I/O ports at e000 [size=128]
        Expansion ROM at 000c0000 [virtual] [disabled] [size=128K]
        Capabilities: <access denied>
        Kernel driver in use: nvidia

[Versions]
libc6:amd64 2.30-0ubuntu3 amd64
libc6:i386 2.30-0ubuntu3 i386
libc6-dbg:amd64 2.30-0ubuntu3 amd64
libc6-dev:amd64 2.30-0ubuntu3 amd64
xserver-xorg-video-nouveau:
  Installed: 1:1.0.16-1
  Candidate: 1:1.0.16-1
  Version table:
 *** 1:1.0.16-1 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages
        100 /var/lib/dpkg/status

[Scarlett Gately Moore (scarlettmoore)]

This bug is very old, if it remains an issue please update the bug with info from a supported release.

[Launchpad Janitor (janitor)]

[Expired for plasma-workspace (Ubuntu) because there has been no activity for 60 days.]