Re: [PATCH 1/2] msi: Invert the sense of the MSI enables.

[Jonathan Lundell]

On May 24, 2007, at 10:51 PM, Andi Kleen wrote:

> > Do we have a feel for how much performace we're losing on those
> > systems which _could_ do MSI, but which will end up defaulting
> > to not using it?
>
> At least on 10GB ethernet it is a significant difference; you usually
> cannot go anywhere near line speed without MSI
>
> I suspect it is visible on high performance / multiple GB NICs too.

Why would that be? As the packet rate goes up and NAPI polling kicks  
in, wouldn't MSI make less and less difference?

I like the fact that MSI gives us finer control over CPU affinity  
than many INTx implementations, but that's a different issue.

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