[arch-general] High CPU on one core, but unable to find process responsible

David Rosenstrauch darose at darose.net
Tue Mar 13 02:03:28 UTC 2018

On 03/12/2018 09:56 PM, Carsten Mattner via arch-general wrote:
> Any BIOS updates or kernel updates recently (4.15.8)?
> Try with 3.16 or 4.9 or another old lts kernel from archive.archlinux.org
> just for testing (not production).
> It's more likely that the kernel regressed rather than IRQ issues popping
> up suddenly. It's possible but less likely.

No BIOS updates.  As far as kernel updates, I do those all the time, so 
not sure that would be the cause.

After doing some digging, though, I did "cat /proc/interrupts", and this 
line stood out, for having an astronomically high number:

            CPU0       CPU1       CPU2       CPU3
  16: 2424156658          0          0          0   IO-APIC  16-fasteoi 
  uhci_hcd:usb5, parport1

I have an old PCI card in the machine that's powers an old parallel port 
printer I used to use with it.  Perhaps that's failing.  I don't need 
the card anymore, so I might as well try taking it out and see if that
makes things better.  If not, I'll be back.  :-)



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