Re: [REGRESSION] 2.6.19/2.6.20-rc3 buffered write slowdown

From: David Chinner
Date: Wed Jan 10 2007 - 20:11:37 EST


On Thu, Jan 11, 2007 at 10:08:55AM +1100, David Chinner wrote:
> On Wed, Jan 10, 2007 at 03:04:15PM -0800, Christoph Lameter wrote:
> > On Thu, 11 Jan 2007, David Chinner wrote:
> >
> > > The performance and smoothness is fully restored on 2.6.20-rc3
> > > by setting dirty_ratio down to 10 (from the default 40), so
> > > something in the VM is not working as well as it used to....
> >
> > dirty_background_ratio is left as is at 10?
>
> Yes.

FWIW, setting dirty_ratio to 20 instead of 10 fixes the most of
the erraticness of the writeback and most of the performance as well.

Cheers,

Dave.
--
Dave Chinner
Principal Engineer
SGI Australian Software Group
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