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Re: mysterious dbench results

To: linux-xfs@xxxxxxxxxxx
Subject: Re: mysterious dbench results
From: Thomas Graichen <news-innominate.list.sgi.xfs@xxxxxxxxxxxxx>
Date: 18 Feb 2001 08:40:12 GMT
Distribution: local
Organization: innominate AG, Berlin, Germany
References: <96nvna$goj$1@mate.bln.innominate.de>
Reply-to: Thomas Graichen <graichen@xxxxxxxxxxxxx>
Reply-to: thomas.graichen@xxxxxxxxxxxxxx
Sender: owner-linux-xfs@xxxxxxxxxxx
User-agent: tin/1.4.4-20000803 ("Vet for the Insane") (UNIX) (Linux/2.4.1-XFS (i686))
small addition: another test - running pgbench from postgres against
postgres 7.1beta4 on the same partition with all three filesystems
on the same machines results in much more logic results: on both
systems the results are best when xfs is used as filesystem -
so looks like the below problem is very specific to dbench
and smp ...

t

p.s.: btw. i reproducable and constantly see about 15% better results
      for the pgbench produced tpc numbers then running the data-
      base on an xfs filesystem compared to ext2 and reiserfs
      which looks pretty good i think - this is for 7.1beta4
      - 7.0.x is worse because of the required fsyncs in it
      which results in xfs being not as good as the others
      (at least ext2 which i compared it to)

Thomas Graichen <graichen@xxxxxxxxxxxxx> wrote:
> i have done some simple dbench test with ext2, reiserfs and xfs - all
> with the same kernel, same partition and run multiple times ... i did
> them on one machine (1 p233mmx, 64mb, ide) and the results looked
> like i expected them to be: all three filesystems are in about the
> same class with xfs the last - but for xfs the io between the dbench
> clients are much better balanced (all end close to eachother at the
> end of the run) - so - as steve once said - this might account for the
> a bit lower xfs results ... ok - then i ran them on another machine
> (2 pII333, 128mb, ide) and on this smp machine i now get only about
> 1/4 of the performance of ext2 and reiserfs with xfs ... it's in this
> setup absolutely reproducable (~1.5mb/sec vs. ~5.5mb/sec) ... i'll
> try to check this on another machine too if i find the time on monday
> - but maybe someone else may try it too - any idea?

> t

> p.s.: all this is with 2.4.1-XFS from about a week ago and without
>       any kio stuff on ide with udma2 enabled

> -- 
> thomas.graichen@xxxxxxxxxxxxxx
>                                                          innominate AG
>                                                   the linux architects
> tel: +49-30-308806-13   fax: -77             http://www.innominate.com

-- 
thomas.graichen@xxxxxxxxxxxxxx
                                                         innominate AG
                                                  the linux architects
tel: +49-30-308806-13   fax: -77             http://www.innominate.com

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