Bug 478417 - System Monitor doesn't display any CPU usage for most applications
Summary: System Monitor doesn't display any CPU usage for most applications
Status: REPORTED
Alias: None
Product: ksystemstats
Classification: Frameworks and Libraries
Component: General (other bugs)
Version First Reported In: unspecified
Platform: Fedora RPMs Linux
: NOR normal
Target Milestone: ---
Assignee: KSysGuard Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-12-11 22:12 UTC by lynne
Modified: 2024-02-08 21:03 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Screenshot of the Applications tab showing that most processes have 0% CPU usage. (162.44 KB, image/png)
2023-12-11 22:12 UTC, lynne
Details
systemd-cgls output (34.81 KB, text/plain)
2023-12-16 21:50 UTC, lynne
Details
htop output vs plasma system monitor (391.75 KB, image/png)
2023-12-16 21:52 UTC, lynne
Details

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Description lynne 2023-12-11 22:12:28 UTC
Created attachment 164097 [details]
Screenshot of the Applications tab showing that most processes have 0% CPU usage.

SUMMARY
Very few applications/processes in Plasma's System Monitor display any CPU usage at all. Htop is able to reliably display this information.


STEPS TO REPRODUCE
1. Open System Monitor
2. Switch to Applications or Processes tab

OBSERVED RESULT
Most applications have a blank entry for CPU usage.

EXPECTED RESULT
Most applications have some level of CPU usage.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kernel 6.5.12-300.fc39.x86_64
(available in About System)
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.111.0
Qt Version: 5.15.11

ADDITIONAL INFORMATION

Screenshots of System Monitor (and htop for comparison) are provided here: https://imgur.com/a/VFwN209
Comment 1 fanzhuyifan 2023-12-14 06:55:13 UTC
I think that is intended behavior. The applications having the blank entries just mean they basically have no CPU usage. Do you see a significant difference between the numbers reported by system monitor and htop?
Comment 2 Arjen Hiemstra 2023-12-14 13:02:09 UTC
It's not intentional, but it seems something is messed up with your CGroup hierarchy. Can you share the output of `systemd-cgls`?
Comment 3 lynne 2023-12-16 21:50:00 UTC
Created attachment 164232 [details]
systemd-cgls output
Comment 4 lynne 2023-12-16 21:52:00 UTC
Created attachment 164233 [details]
htop output vs plasma system monitor
Comment 5 lynne 2023-12-16 21:52:43 UTC
(In reply to fanzhuyifan from comment #1)
> I think that is intended behavior. The applications having the blank entries
> just mean they basically have no CPU usage. Do you see a significant
> difference between the numbers reported by system monitor and htop?

I do, yes. I've attached a screenshot comparing the two. See this attachment: https://bugs.kde.org/attachment.cgi?id=164233
Comment 6 lynne 2023-12-16 21:53:02 UTC
(In reply to Arjen Hiemstra from comment #2)
> It's not intentional, but it seems something is messed up with your CGroup
> hierarchy. Can you share the output of `systemd-cgls`?

I've attached the output of the command here: https://bugs.kde.org/attachment.cgi?id=164232
Comment 7 Bug Janitor Service 2023-12-31 03:46:05 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!