From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 3/3] xfs simplify and speed up direct I/O completions
Date: Tue, 20 Jul 2010 18:08:52 +1000 [thread overview]
Message-ID: <20100720080852.GN32635@dastard> (raw)
In-Reply-To: <20100718211820.739557136@bombadil.infradead.org>
On Sun, Jul 18, 2010 at 05:17:11PM -0400, Christoph Hellwig wrote:
> Our current handling of direct I/O completions is rather suboptimal,
> because we defer it to a workqueue more often than needed, and we
> perform a much to aggressive flush of the workqueue in case unwritten
> extent conversions happen.
>
> This patch changes the direct I/O reads to not even use a completion
> handler, as we don't bother to use it at all, and to perform the unwritten
> extent conversions in caller context for synchronous direct I/O.
>
> For a small I/O size direct I/O workload on a consumer grade SSD, such as
> the untar of a kernel tree inside qemu this patch gives speedups of
> about 5%. Getting us much closer to the speed of a native block device,
> or a fully allocated XFS file.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Looks a lot saner - getting rid of the workqueue flushes is a good
thing.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
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prev parent reply other threads:[~2010-07-20 8:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-18 21:17 [PATCH 0/3] direct I/O fixes and speedups Christoph Hellwig
2010-07-18 21:17 ` [PATCH 1/3] direct-io: move aio_complete into ->end_io Christoph Hellwig
2010-07-18 21:17 ` [PATCH 2/3] xfs: move aio completion after unwritten extent conversion Christoph Hellwig
2010-07-20 7:59 ` Dave Chinner
2010-07-18 21:17 ` [PATCH 3/3] xfs simplify and speed up direct I/O completions Christoph Hellwig
2010-07-20 8:08 ` Dave Chinner [this message]
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