Arch Linux

PeerK

Member

Registered: 2020-06-24

Posts: 40

After hours of work normally kworker consumes suddenly 100% CPU

Hi all,

I am running Arch with KDE Plasma on a Ryzen 8840 (8C/16T, 16 GB RAM) and while the machine works nicely for hours, it suddenly gets nearly unusable: Keyboard and mouse reacts delayed by 1-3 sec. I went to a console and in top/htop it turns out, that a kworker process consumes 100% of one cpu.

Since I just learned, that kworker "is a placeholder process for kernel worker threads, which perform most of the actual processing for the kernel", there are probably some tools, to log what is going on in more detail.

It usually happens while using Firefox and editing some text. But this doesn't mean too much, since I spend almost 70% of the time working with Firefox.

Could anybody give me a helping hand, how and what to log to get a better understanding, what is going on?

System:
  Host: xxxx Kernel: 6.12.1-arch1-1 arch: x86_64 bits: 64 compiler: gcc
    v: 14.2.1 clocksource: hpet avail: acpi_pm
    parameters: initrd=\initramfs-linux.img
    cryptdevice=UUID=xxxxxxxxxxxxxxxxxxxxxxxx:luks
    root=/dev/mapper/xxxxxxxx-root pcie_aspm=off rw
  Desktop: KDE Plasma v: 6.2.4 tk: Qt v: N/A wm: kwin_wayland dm: SDDM
    Distro: Arch Linux
Memory:
  System RAM: total: 16 GiB available: 13.4 GiB used: 4.76 GiB (35.5%)
  Array-1: capacity: 16 GiB slots: 4 modules: 4 EC: None

Thank you and kind regards, Peer

Last edited by PeerK (2024-12-01 10:12:38)

pvtvega

Member

Registered: 2024-11-25

Posts: 90

Re: After hours of work normally kworker consumes suddenly 100% CPU

It's difficult to say what could be the reason without some more detail. Can you post the output of

top

next time this happens? Is your system usually close to 100% RAM usage when you notice the spike in CPU?

seth

Member

Registered: 2012-09-03

Posts: 59,885

Re: After hours of work normally kworker consumes suddenly 100% CPU

Next to the ram (free -h) and what consumes it (top, /proc/meminfo), please post the output of

swapon

tl;Dr - don't use zswap AND zram and if you're using zswap you need a physical swap device to support it (doesn't have to be a partition, can be a swapfile)

Sidebar: "UUID=xxxxxxxxxxxxxxxxxxxxxxxx", the UUID doesn't reveal anything and isn't bound to your hardware - it exists for collision prevention when addressing partitions.
The only thing is that it's traceable (ie. if you post it around the internet, one can link those posts as referring to the same system)

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