From: Mel Gorman <mgorman@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [MMTests] dbench4 async on ext3
Date: Wed, 22 Aug 2012 11:48:06 +0100 [thread overview]
Message-ID: <20120822104806.GD15058@suse.de> (raw)
In-Reply-To: <20120821220038.GA19171@quack.suse.cz>
On Wed, Aug 22, 2012 at 12:00:38AM +0200, Jan Kara wrote:
> On Mon 23-07-12 22:21:46, Mel Gorman wrote:
> > Configuration: global-dhp__io-dbench4-async-ext3
> > Result: http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-dbench4-async-ext3
> > Benchmarks: dbench4
> >
> > Summary
> > =======
> >
> > In general there was a massive drop in throughput after 3.0. Very broadly
> > speaking it looks like the Read operation got faster but at the cost of
> > a big regression in the Flush operation.
>
> Mel, I had a look into this and it's actually very likely only a
> configuration issue. In 3.1 ext3 started to default to enabled barriers
> (barrier=1 in mount options) which is a safer but slower choice. When I set
> barriers explicitely, I see no performance difference for dbench4 between
> 3.0 and 3.1.
>
I've confirmed that disabling barriers fixed it, for one test machine and
one test at least. I'll reschedule the tests to run with barriers disabled
at some point in the future. Thanks for tracking it down, I was at least
two weeks away before I got the chance to even look.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2012-08-22 10:48 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120620113252.GE4011@suse.de>
[not found] ` <20120629111932.GA14154@suse.de>
2012-06-29 11:23 ` [MMTests] IO metadata on ext3 Mel Gorman
2012-06-29 11:24 ` [MMTests] IO metadata on ext4 Mel Gorman
2012-06-29 11:25 ` [MMTests] IO metadata on XFS Mel Gorman
2012-07-01 23:54 ` Dave Chinner
2012-07-02 6:32 ` Christoph Hellwig
2012-07-02 14:32 ` Mel Gorman
2012-07-02 19:35 ` Mel Gorman
2012-07-03 0:19 ` Dave Chinner
2012-07-03 10:59 ` Mel Gorman
2012-07-03 11:44 ` Mel Gorman
2012-07-03 12:31 ` Daniel Vetter
2012-07-03 13:08 ` Mel Gorman
2012-07-03 13:28 ` Eugeni Dodonov
2012-07-04 0:47 ` Dave Chinner
2012-07-04 9:51 ` Mel Gorman
2012-07-03 13:04 ` Mel Gorman
2012-07-03 14:04 ` Daniel Vetter
2012-07-02 13:30 ` Mel Gorman
2012-07-05 14:56 ` [MMTests] Interactivity during IO on ext3 Mel Gorman
2012-07-10 9:49 ` Jan Kara
2012-07-10 11:30 ` Mel Gorman
2012-07-05 14:57 ` [MMTests] Interactivity during IO on ext4 Mel Gorman
2012-07-23 21:21 ` [MMTests] dbench4 async on ext3 Mel Gorman
2012-08-16 14:52 ` Jan Kara
2012-08-21 22:00 ` Jan Kara
2012-08-22 10:48 ` Mel Gorman [this message]
2012-07-23 21:23 ` [MMTests] dbench4 async on ext4 Mel Gorman
2012-07-23 21:24 ` [MMTests] Threaded IO Performance on ext3 Mel Gorman
2012-07-23 21:25 ` [MMTests] Threaded IO Performance on xfs Mel Gorman
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