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From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Mel Gorman <mgorman@suse.de>,
	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 02:32:26 -0400	[thread overview]
Message-ID: <20120702063226.GA32151@infradead.org> (raw)
In-Reply-To: <20120701235458.GM19223@dastard>

On Mon, Jul 02, 2012 at 09:54:58AM +1000, Dave Chinner wrote:
> 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...

I think the patch to do that conversion still needs review..

> 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...

When I checked it it could only be called twice, and we'd already
optimize away the second call.  I'd defintively like to track down where
the performance changes happend, at least to a major version but even
better to a -rc or git commit.

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  reply	other threads:[~2012-07-02  6:32 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-20 11:32 MMTests 0.04 Mel Gorman
2012-06-29 11:19 ` Mel Gorman
2012-06-29 11:21   ` [MMTests] Page allocator Mel Gorman
2012-06-29 11:22   ` [MMTests] Network performance Mel Gorman
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 [this message]
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
2012-07-04 15:52   ` [MMTests] Page reclaim performance on ext3 Mel Gorman
2012-07-04 15:53   ` [MMTests] Page reclaim performance on ext4 Mel Gorman
2012-07-04 15:53   ` [MMTests] Page reclaim performance on xfs 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 21:12   ` [MMTests] Scheduler Mel Gorman
2012-07-23 21:13   ` [MMTests] Sysbench read-only on ext3 Mel Gorman
2012-07-24  2:29     ` Mike Galbraith
2012-07-24  8:19       ` Mel Gorman
2012-07-24  8:32         ` Mike Galbraith
2012-07-23 21:14   ` [MMTests] Sysbench read-only on ext4 Mel Gorman
2012-07-23 21:15   ` [MMTests] Sysbench read-only on xfs Mel Gorman
2012-07-23 21:17   ` [MMTests] memcachetest and parallel IO on ext3 Mel Gorman
2012-07-23 21:19   ` [MMTests] memcachetest and parallel IO on xfs Mel Gorman
2012-07-23 21:20   ` [MMTests] Stress high-order allocations on ext3 Mel Gorman
2012-07-23 21:21   ` [MMTests] dbench4 async " 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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