diagnosing interrupt storms?

[Scott Long]

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?
>
> (also I my laptop still can't boot with top-of-the-tree current) :(
>

A dmesg here would help, of course.  You might have a similar problem as
me, where the SMI interrupt is misconfigured as active-low instead of
active-high, so it storms the system.  Does disabling ACPI make a
difference?  Since it's SMP, does disabling APIC (and thus turning it into
UP) make a difference?

Scott