watchdog/n high CPU usage - how to check what's going on?

[Jarosław Górny]

Hi,

question as in the subject. I'd like to check what is causing this
before submitting to bugzilla. I'm on F19, and I checked this on last 3
kernels:
kernel-3.9.9-301.fc19.x86_64
kernel-3.9.9-302.fc19.x86_64
kernel-3.10.3-300.fc19.x86_64

CPU usage for watchdog/1 oscillates between 30% and even > 100%, only
falling below 10% for 1-2 second every 10 seconds.
Furthermore, kworker/n:m is next one to follow, using 10-40% CPU.

I noticed this couple of days ago. I tried to find something useful on
net, but without any luck.
Any hints where and how to start?

Thanks,
-- 
jaroslav