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Smit-Tay
11th December 2014, 12:08 PM
Can anyone explain the rcuos/rcuob processes that have suddenly appeared since upgrading from F20 to F21 ?

I currently have 64 instances of each running.

What are they ?
Is it normal to have 64 of each ?
Should I be afraid, very afraid ?

Smit-Tay
12th December 2014, 10:34 AM
As a follow up to my question...

I have discovered that these processes have something to do with the kernel's attempt at efficient thread use.

I'm not sure I understand how making additional processes helps anything, but hey, I'm no kernel developer.

Anyway, I'm still hoping someone can explain this, and perhaps how to eliminate them or at least make them disappear from the running processes list.

dobbi
12th December 2014, 12:08 PM
Don't know about the implementation of it but is about this.

https://en.wikipedia.org/wiki/Read-copy-update

Smit-Tay
12th December 2014, 01:09 PM
Yes, I got to that Wikipedia page as well. I understand the concept of RCU locks, and the need for them in the kernel.

What I don't understand is why I would suddenly see 64 rcuos and 64 rcuob processes running. I am fairly confident this was not occurring on my pre F21 (my previous installation of F20) task listl

dobbi
13th December 2014, 09:32 AM
A DB?logfile?

have you tried tracing it?

e.g.:

strace -o "/home/pinky&brains/Documents/2014-12-13-rcutrace.txt" -p 1490&

Counting sys calls.
e.g.:

strace -c -p 1490&

Smit-Tay
30th January 2015, 04:11 PM
Problem disappeared after update(?)/reboot