Re: [PATCH 1/3] xfs: introduce an allocation workqueue

Dave Chinner
2011-07-19T03:14:33Z

On Mon, Jul 18, 2011 at 10:02:14PM -0400, Christoph Hellwig wrote:
> On Tue, Jul 19, 2011 at 11:24:50AM +1000, Dave Chinner wrote:
> > Honestly, I'd prefer not to do that because it's a slippery slope.
> > I've got plenty more "do stuff in the background via workqueues"
> > patches lined up, so if we start adding knobs/mount options to turn
> > each of them off "just in case there's an issue".
> >
> > So far I haven't found any issues at all and I've been running this
> > split allocation stack like this in -all- my performance testing for
> > the past 2-3 months. I know that is not conclusive, but if the
> > bechmarks I've been using to improve XFS performance over the past
> > 18 months don't show regressions, that's fairly indicative of the
> > fact that most workloads won't even notice the change....
>
> Maybe. One thing I'd like to see is stuff like high-iop direct or
> O_SYNC I/O that actually calls the allocator.

What do you want me to run? I don't have any particularly high IOP
hardware here, but I might be able to do something that just hits
the BBWC....

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com