Re: [PATCH 1/6] Rewrite MSI-HOWTO

Matthew Wilcox
2009-03-02T21:02:20Z

On Mon, Mar 02, 2009 at 01:33:40PM -0700, Grant Grundler wrote:
> AFAICT "round-robin" was a behavior of older kernels.
> All the x86 platforms I've looked at direct the MSI to exactly
> one CPU.

I think it's a factor of your chipset. For example, my laptop:

$ grep MSI /proc/interrupts
26: 33095 33046 PCI-MSI-edge eth0
27: 127014 126190 PCI-MSI-edge ahci
28: 0 0 PCI-MSI-edge ahci
29: 0 0 PCI-MSI-edge ahci
31: 525988 518310 PCI-MSI-edge iwlagn

I know my G33-based desktop also distributes interrupts equally across
all four cores. It is, of course, possibly to manually set the
affinity, and perhaps that's what you're seeing.

> > Did you see this is patch 1/6? ;-)
>
> yes....after I hit send and continued reviewing the rest of the patches. ;)

It's good to know somebody looked at patches 2-6 because I've not had
any comments yet.

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."