Re: interrupt misrouting and storms in dom0?

[Thor Lancelot Simon <tls%rek.tjls.com@localhost>]

On Tue, Apr 28, 2009 at 11:23:18AM -0400, Thor Lancelot Simon wrote:
>
> I have a system which seems to generate a huge number of spurious
> interrupts in the dom0 under load.  I should note that this system
> requires ACPI to be disabled in order to run properly *without* xen
> but I have never figured out why (mpt seems to never get interrupts).
> With xen, device interrupts are delivered -- oh, are they ever!

I updated to today's sources -- same problem.  Funny that it's the
same ioapic, but the pin is off by one from the device that _should_
be generating (many less) interrupts.  I know Andy recently saw some
kind of severe problem with the ioapic interrupt code and had to back
out interrupt shielding -- I wonder if there's an off-by-one error in
the interrupt delivery or acknowledgment somewhere?

I've looked at that code before and found it completely impenetrable
after several hours' work so I fear I will be little help if that or
something like it is the case. :-/

Thor