From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Martin Sustrik <sustrik@fastmq.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Martin Lucina <mato@kotelna.sk>,
linux-kernel@vger.kernel.org
Subject: Re: Higher than expected disk write(2) latency
Date: Thu, 10 Jul 2008 09:31:09 +0100 [thread overview]
Message-ID: <20080710093109.46db7c40@the-village.bc.nu> (raw)
In-Reply-To: <4875C45C.2010901@fastmq.com>
> What we see is that AIO performs rather bad while we are still
> enqueueing more writes (it misses right position on the disk and has to
> do superfluous disk revolvings), however, once we stop enqueueing new
> write request, those already in the queue are processed swiftly.
Which disk scheduler are you using - some of the disk schedulers
intentionally delay writes to try and get better block merging.
Alan
next prev parent reply other threads:[~2008-07-10 9:04 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-28 12:11 Martin Lucina
2008-06-28 13:11 ` Roger Heflin
2008-06-30 18:10 ` Martin Sustrik
2008-06-30 19:02 ` Roger Heflin
2008-06-30 22:20 ` Martin Sustrik
2008-07-01 0:11 ` Bernd Eckenfels
2008-07-02 16:48 ` Martin Sustrik
2008-07-02 18:15 ` Jeff Moyer
2008-07-02 18:20 ` Martin Sustrik
2008-07-04 3:16 ` David Dillow
2008-07-02 21:33 ` Roger Heflin
2008-06-28 14:47 ` David Newall
2008-06-29 11:34 ` Martin Sustrik
2008-07-10 5:27 ` Andrew Morton
2008-07-10 8:12 ` Martin Sustrik
2008-07-10 8:14 ` Andrew Morton
2008-07-10 13:29 ` Chris Mason
2008-07-10 13:41 ` Martin Lucina
2008-07-10 14:01 ` Arjan van de Ven
2008-07-10 14:18 ` Chris Mason
2008-07-10 8:31 ` Alan Cox [this message]
2008-07-10 13:17 ` Martin Sustrik
2008-07-10 13:18 ` Andrew Morton
2008-07-11 15:17 ` Martin Sustrik
[not found] <fa.OZMA74BZPX46rhnjz1am4hB786M@ifi.uio.no>
2008-06-30 6:41 ` Robert Hancock
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