Subject: Re: [net-next-2.6 PATCH 2/3] ixgbe: Set MSI-X vectors to NOBALANCING and set affinity

From: Stephen Hemminger <[email-masked]>
Date: Fri, 23 Oct 2009 06:45:52 +0900

On Thu, 22 Oct 2009 03:56:01 -0700 (PDT)
David Miller <[email-masked]> wrote:

> From: Peter P Waskiewicz Jr <[email-masked]>
> Date: Thu, 22 Oct 2009 01:22:36 -0700
> 
> > The first thing any performance guide says is to disable irqbalance
> 
> Such guides are wrong, and that's the end of this discussion.
> 
> These kinds of guides also say to do all kinds of crazy things with
> the socket sysctl settings.  That's wrong too and we absolutely do not
> do things to accomodate nor support those guide suggestions.
> 
> And we won't do that here.
> 
> I'm especially not going to succumb in this case because Arjan has
> been more than responsive to making sure irqbalanced in userspace does
> the right thing for networking devices, even multiqueue ones.
> 
> So we can make it do the right thing when flow director is present.
> In fact, the thing you want for flow director makes sense in the
> general case too.

irqbalance daemon already has IRQBALANCE_BANNED_INTERRUPTS
to work around this. It also has code to special case devices, if you
think ixgbe needs special treatment, why not do it there.