Re: Redirectable IRQs

[Grant Grundler <iod00d@hp.com>]

On Thu, May 12, 2005 at 12:15:41PM -0700, Michael.Meduna@Bull.com wrote:
> Is there a way to permanently disable interrupts for specific CPUs.

Yes - but it may not be exactly what you want.
See /proc/irq/*/smp_affinity.

I'm not sure what /sys/class/pci_bus/*/cpuaffinity does.
It looks like a cpu set mask though.

...
> I have a few critical applications each bound to a cpuset with its
> own processor.  Ideally, I would not want these CPUs to take interrupts.

Simple solution is to bind each IRQ "manually" to a single processor.

> Is there a way to set the XTP register such that processors
> 4-7 will never take an interrupt?

ISTR, HP IA64 platforms do not implement XTP.
Binding IRQs 1:1 with CPUs was seen as a better choice.
MSI-X allows intelligent 1:N if devices really need to load
multiple CPUs.

grant