From: Dave Chinner <david@fromorbit.com>
To: Mel Gorman <mgorman@suse.de>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: [MMTests] IO metadata on XFS
Date: Mon, 2 Jul 2012 09:54:58 +1000 [thread overview]
Message-ID: <20120701235458.GM19223@dastard> (raw)
In-Reply-To: <20120629112505.GF14154@suse.de>
On Fri, Jun 29, 2012 at 12:25:06PM +0100, Mel Gorman wrote:
> Configuration: global-dhp__io-metadata-xfs
> Benchmarks: dbench3, fsmark-single, fsmark-threaded
>
> Summary
> =======
> Most of the figures look good and in general there has been consistent good
> performance from XFS. However, fsmark-single is showing a severe performance
> dip in a few cases somewhere between 3.1 and 3.4. fs-mark running a single
> thread took a particularly bad dive in 3.4 for two machines that is worth
> examining closer.
That will be caused by the fact we changed all the metadata updates
to be logged, which means a transaction every time .dirty_inode is
called.
This should mostly go away when XFS is converted to use .update_time
rather than .dirty_inode to only issue transactions when the VFS
updates the atime rather than every .dirty_inode call...
> Unfortunately it is harder to easy conclusions as the
> gains/losses are not consistent between machines which may be related to
> the available number of CPU threads.
It increases the CPU overhead (dirty_inode can be called up to 4
times per write(2) call, IIRC), so with limited numbers of
threads/limited CPU power it will result in lower performance. Where
you have lots of CPU power, there will be little difference in
performance...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2012-07-01 23:54 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 [this message]
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
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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