Re: IO queuing and complete affinity with threads (was Re: [PATCH 0/8] IO queuing and complete affinity)

Jens Axboe
2008-02-08T08:24:37Z

On Fri, Feb 08 2008, Nick Piggin wrote:
> On Fri, Feb 08, 2008 at 08:59:55AM +0100, Jens Axboe wrote:
> > On Fri, Feb 08 2008, Nick Piggin wrote:
> > > And if you don't?
> >
> > Well if you don't ask for anything, you wont get anything :-)
> > As I mentioned, the patch is a playing ground for trying various setups.
> > Everything defaults to 'do as usual', set options to setup certain test
> > scenarios.
>
> I mean if you don't know the completing CPU.

I still don't know quite what part of that patch you are referring to
here. If you don't have queue_affinity set, queueing a new request with
the hardware is generally done on the same CPU that just completed a
request. That is true even without any patches.

--
Jens Axboe