Re: [PATCH 3/6] writeback: sync expired inodes first in background writeback

Dave Chinner
2011-04-21T01:01:40Z

On Wed, Apr 20, 2011 at 03:38:22PM +0800, Wu Fengguang wrote:
> > make. Please test against a vanilla kernel if that is what you are
> > aiming these patches for. If you aren't aiming for a vanilla kernel,
> > please say so in the patch series header...
>
> Here are the test results for vanilla kernel. It's again shows better
> numbers for dd, tar and overall run time.
>
> 2.6.39-rc3 2.6.39-rc3-dyn-expire+
> ------------------------------------------------
> all elapsed 256.043 252.367
> stddev 24.381 12.530
>
> tar elapsed 30.097 28.808
> dd elapsed 13.214 11.782

The big reduction in run-to-run variance is very convincing - moreso
than the reduction in runtime - That's kind of what I had hoped
would occur once I understood the implications of the change. Thanks
for running the test to close the loop. :)

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com