Score:1

Kernel worker uses one core at 80% all the time

cn flag

I'm having a problem with kernel using much cpu on latest ubuntu 21.10.

one core is used at 80%

the kworker uses actually 10% of CPU which is 80% on one core

I've tried to do this workaround: https://www.linuxquestions.org/questions/linux-software-2/high-cpu-usage-by-kworker-4175563563/ but matter what I did, I can't modify the dirty_writeback_centisecs file. Sometimes after some "Main components update" or GPU driver update problem goes away, but then it returns, and I have no idea what to do.

vanadium avatar
cn flag
A bug as old as the street, not frequently reported because many users find it normal that the fan is on all the time. The accepted answer in the thread I referred to helped me. It is rather complicated, though: you have to identify and disable interrupts that cause the problem. For me, it was enough to disable gpe13. I have this in effect since 2019 - would need to test if it is still needed in Ubuntu 21.10.
dronostyka avatar
cn flag
So I've just tried these solutuions: https://askubuntu.com/questions/176565/why-does-kworker-cpu-usage-get-so-high but it says no permision when i try to disable interrurpt which has high number I get permision denied.
dronostyka avatar
cn flag
How did you disable them? Because for me even using sudo won't let it disable. I'm wondering if disabling whole ACPI would help..
vanadium avatar
cn flag
I just followed the instructions. I live with a line in my crontab, and with a `/etc/pm/sleep.d/30_disable_gpe6F` file that executes the same command after sleep or hibernate. Still from 19.10: against better advise, I have been upgrading since then rather than installing anew.
dronostyka avatar
cn flag
Seems like it says no permission, but now CPU usage loks good.
vanadium avatar
cn flag
I cannot see where it could say that, but anyway, keep a watch. If not solved, the problem will reappear any time sooner or later after rebooting.
dronostyka avatar
cn flag
Yes you were right, usage seems to go away while working on battery. I had to reinstall ubuntu yesterday and now it's ok.
dronostyka avatar
cn flag
I have also noticed that reconnecting external display removes the problem for some time.
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