[SOLVED] CPU core spike

freebench · 2026-03-20 13:38:45

hi

One of the CPU cores - #6, all the time loaded near 100%.
This takes place right after reboot, so nothing that I manually run can trigger this.
It started to show up about a month ago.
When this takes place the system performance decrease.
Unfortunately a process list does not show a vivid suspect process that might've caused the spike.

I had some apps running which use libnotify(notification server) about the same time the issue started to pop, like showing custom notifications.
Although, I'm not sure whether this might cause it. Or how to investigate? Maybe there is a pending queue that needs to be cleaned up or smth like that.
Please advice.

HTOP

Last edited by freebench (2026-03-20 16:39:40)

twelveeighty · 2026-03-20 14:53:08

Please don't ask us to guess, give us actual logs: see Post complete logs.

seth · 2026-03-20 15:54:51

Also https://man.archlinux.org/man/htop.1#K but this likely causes some kernel messages as well.

freebench · 2026-03-20 16:39:20

For some reason the htop did not show the process causing spike, but the top did.
it was this `irq/88-nxp-nci_i2c` command
the top showed around 20-30% CPU util.

Here is the most likely cause
It's the NFC scanner in my laptop Lenovo ThinkPad Gen3 AMD.

# dmesg | grep -i nxp-nci` => `[   15.239853] nxp-nci_i2c i2c-NXP1001:00: NFC: Read failed with error -121`

I'm not sure whether the approach taken is the correct one
killing the process by ID does not fix it, it launched again right away

// check if this module loaded
$ lsmod | grep -i nxp_nci_i2c
// after module removal, the system calmed down instantly
# rmmod nxp_nci_i2c

Blacklist module
I used kernel command line method
After reboot it's back to normal

Arch Linux

#1 2026-03-20 13:38:45

[SOLVED] CPU core spike

#2 2026-03-20 14:53:08

Re: [SOLVED] CPU core spike

#3 2026-03-20 15:54:51

Re: [SOLVED] CPU core spike

#4 2026-03-20 16:39:20

Re: [SOLVED] CPU core spike

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