Re: [RFC PATCH] cfq-iosched: IOPS mode for group scheduling and newgroup_idle tunable

From: Vivek Goyal
Date: Mon Jul 26 2010 - 09:54:29 EST

On Mon, Jul 26, 2010 at 09:48:18AM -0400, Christoph Hellwig wrote:
> On Mon, Jul 26, 2010 at 09:43:29AM -0400, Vivek Goyal wrote:
> > > Don't know if this is related, but I'm not quite shure if XFS (which I use
> > > exclusively) uses the jbd/jbd2 journaling layer at all.
> >
> > I also don't know. But because this patch is making a difference with your
> > XFS file system performance, may be it does use.
> >
> > CCing Christoph, he can tell us.
> No, of course XFS doesn't use jbd.

Hmm.., interesting. So somewhere WRITE_SYNC idling in CFQ is hurting XFS
performance also. This time for some other reason and not jbd/jbd2.


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