kernel: interrupt storm detected on "irq22:"; throttling interrupt source [7.0-RELEASE]

[Oliver Peter]

On Tue, Sep 09, 2008 at 02:24:16PM -0400, John Baldwin wrote:
> On Monday 08 September 2008 07:08:05 pm Oliver Peter wrote:
> > ...
> > ... of course I could do that - but could you please be so kind and
> > explain how to do that?  :-)
> 
> Well, you could start by adding a printf to ata's interrupt handler, but that 
> would result in a flood on your screen.  You could maybe use a KTR instead, 
> but only do it if the interrupt handler doesn't find any work to do (e.g. no 
> pending request) perhaps.  I think the ATA interrrupt handler already reads a 
> status register of some sort, but I could be wrong.

I feels like I need a rosetta stone for that...  :)

This is my "production" machine in the datacenter 2,000km away -
I would love to debug that interrupt storm with KTR, but I'm not sure
what I'm doing at all and nobody can ensure that my machine will
come up again after that...

Anyway I would like to learn more about the KTR stuff.
I've never heard about that before, is that a good point to start out?

     http://www.watson.org/~robert/freebsd/netperf/ktr/

Furthermore I found out that this interrupt storm actally HAS a very bad
impact in I/O performance of the harddisks...  I'm at 9MB/s writing speed
with dd.  Normally I'm at about 60MB/s.

Cheers.

-- 
Oliver PETER, email: oliver at peter.de.com, ICQ# 113969174
"If it feels good, you're doing something wrong."
                                      -- Coach McTavish