diagnosing interrupt storms?

[Doug White]

On Mon, 8 Mar 2004, Alfred Perlstein wrote:

> At a certain point after booting my SMP 5-current box gets all
> weird, typically I see 50%+ time spent in interrupt.  If I run "top
> -S" I typically see one of the ithreads using 50% cpu.
>
> I'm trying to figure out what it's doing, what has gone wrong etc.
>
> Are there any sysctls to look at or things I can do to diagnose
> this?

vmstat -i is useful for figuring out exactly which interrupt is storming,
although the ithread might hint it too.

Which one is it?

-- 
Doug White                    |  FreeBSD: The Power to Serve
dwhite at gumbysoft.com          |  www.FreeBSD.org