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Subject: Re: [PATCH] genirq: Set initial default irq affinity to just CPU0
From: David Miller <davem@davemloft.net>
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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Sun, 26 Oct 2008 17:48:43 +1100

> 
> > What does this all mean to my GigE (dual 1.1 GHz 7455s)? Is this
> > thing supposed to be able to spread irq between its cpus?
> 
> Depends on the interrupt controller. I don't know that machine
> but for example the Apple Dual G5's use an MPIC that can spread
> based on an internal HW round robin scheme. This isn't always
> the best idea tho for cache reasons... depends if an at what level
> your caches are shared between CPUs.

it's always going to be the wrong thing to do for networking cards,
especially once we start doing RX flow seperation in software