Re: filesystem benchmarking fun

From: Chris Mason
Date: Wed May 16 2007 - 15:29:30 EST


On Wed, May 16, 2007 at 08:12:09PM +0200, Jan Engelhardt wrote:
>
> On May 16 2007 10:42, Chris Mason wrote:
> >
> >For example, I'll pick on xfs for a minute. compilebench shows the
> >default FS you get from mkfs.xfs is pretty slow for untarring a bunch of
> >kernel trees.
>
> I suppose you used 'nobarrier'? [ http://lkml.org/lkml/2006/5/19/33 ]

Oddly, xfs fails barriers on this sata drive although the other filesystems
don't. But yes, I tried both ways.

>
> >Dave Chinner gave me some mount options that make it
> >dramatically better,
>
> and `mkfs.xfs -l version=2` is also said to make it better

I used mkfs.xfs -l size=128m,version=2
mount -o logbsize=256k,nobarrier

>
> >but it still writes at 10MB/s on a sata drive that
> >can do 80MB/s. Ext3 is better, but still only 20MB/s.
> >
> >Both are presumably picking a reasonable file and directory layout.
> >Still, our writeback algorithms are clearly not optimized for this kind
> >of workload. Should we fix it?
>
> Also try with tmpfs.
>
Sorry, I'm not entirely clear on what we learn from trying tmpfs?

-chris

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