Arch Linux

gfurst

Member

Registered: 2014-09-27

Posts: 8

I got something 100% hogging CPU but I cannot figure out what it is

Pretty much the title, but picture show it better:

Neither Ksysguard or top shows any relevant processes, I've tried stopping all superfluous services and but it still remains.
A brief search tells me it could be interrupt calls from something going wrong, but the methods I tried didn't show anything off.

I don't know when this start, if from the last update or something else, but I only noticed because the CPU was being slightly noisier when it shouldn't be, its hogging only one core out of twelve, so it really didn't bother otherwise. Still, feels like something important to figure out why its happening.

Sys info:
Operating System: Arch Linux
KDE Plasma Version: 5.27.6
KDE Frameworks Version: 5.108.0
Qt Version: 5.15.10
Kernel Version: 6.4.6-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 12 × AMD Ryzen 5 4600G with Radeon Graphics
Memory: 27,3 GiB of RAM
Graphics Processor: AMD Radeon RX 570 Series
Manufacturer: Micro-Star International Co., Ltd.
Product Name: MS-7C51

also of note: I know I should be upgrading before complaining, but I have yet another issue with sys-upgrades that I need to figure before doing that.

Last edited by gfurst (2023-09-16 18:26:47)

loqs

Member

Registered: 2014-03-06

Posts: 18,180

Re: I got something 100% hogging CPU but I cannot figure out what it is

Have you tried finding what interrupts are on the 100% CPU from /proc/interrupts then finding out what that interrupt is from `lsirq`?

Last edited by loqs (2023-09-16 18:36:20)

gfurst

Member

Registered: 2014-09-27

Posts: 8

Re: I got something 100% hogging CPU but I cannot figure out what it is

Have you tried finding what interrupts are on the 100% CPU from /proc/interrupts then finding out what that interrupt is from `lsirq`?

I don't know how to do that.
All I had was "watch -n1 cat /proc/interrupts" that didn't seem to have anything relevant, tho now maybe the enp37 is standing out?

loqs

Member

Registered: 2014-03-06

Posts: 18,180

Re: I got something 100% hogging CPU but I cannot figure out what it is

Assuming CPU11 from the first image is CPU10 from the second with the difference being due to counting from 1 rather than 0 then yes you have identified enp37.

gfurst

Member

Registered: 2014-09-27

Posts: 8

Re: I got something 100% hogging CPU but I cannot figure out what it is

Assuming CPU11 from the first image is CPU10 from the second with the difference being due to counting from 1 rather than 0 then yes you have identified enp37.

Yes that would be my assumption, and enp37s0 should be the ethernet module right? So what does that tell me?
Also a previous suspect I had from top was:

4466    guiu     20  0   228,4m  6,8m   5,3   0,0   10:30.43  S ksgrd_network_h

Which supposedly has to do with monitoring internet traffic, I've found this weird but just in case, removed any eth monitor applets, and even ending the process, but without success.
Edit: Just to add to this, I'm pretty sure ksgrd is not to blame, while its high usage while its open, CPU usage never drops below 8%( which is about 1/12 core).

Last edited by gfurst (2023-09-16 19:24:59)

gfurst

Member

Registered: 2014-09-27

Posts: 8

Re: I got something 100% hogging CPU but I cannot figure out what it is

Well that got me puzzled.
But anyway, I risked a sys-upgrade and it went well, on top of that, doesn't seem like the issue persisted.
So good news on both fronts.