Re: Fall back io scheduler for 2.6.15?

From: Jens Axboe
Date: Mon Jan 16 2006 - 03:40:12 EST


On Fri, Jan 13 2006, Andrew Morton wrote:
> Mingming Cao <cmm@xxxxxxxxxx> wrote:
> >
> > On 2.6.14, the
> > fall back io scheduler (if the chosen io scheduler is not found) is set
> > to the default io scheduler (anticipatory, in this case), but since
> > 2.6.15-rc1, this semanistic is changed to fall back to noop.
>
> OK. And I assume that AS wasn't compiled, so that's why it fell back?
>
> I actually thought that elevator= got removed, now we have
> /sys/block/sda/queue/scheduler. But I guess that's not very useful with
> CONFIG_SYSFS=n.
>
> > Is there any reason to fall back to noop instead of as? It seems
> > anticipatory is much better than noop for ext3 with large sequential
> > write tests (i.e, 1G dd test) ...
>
> I suspect that was an accident. Jens?

It is, it makes more sense to fallback to the default of course.

--
Jens Axboe

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