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From: Alan <alan@lxorguk.ukuu.org.uk>
To: Arjan van de Ven <arjan@infradead.org>
Cc: "Martin A. Fink" <fink@mpe.mpg.de>,
	Matthias Schniedermeyer <ms@citd.de>,
	linux-kernel@vger.kernel.org
Subject: Re: SATA-performance: Linux vs. FreeBSD
Date: Tue, 13 Feb 2007 11:27:58 +0000	[thread overview]
Message-ID: <20070213112758.5920a28e@localhost.localdomain> (raw)
In-Reply-To: <1171361290.12771.77.camel@laptopd505.fenrus.org>

> there's several tunables you can do;
> 1) increase /sys/block/<device>/queue/nr_requests
>    the linux default is on the low side
> 5) echo a larger value into /sys/block/<device>/queue/max_sectors_kb
>    the default seems to be 512 which is... really low. The hw max is in
>    another file in that directory; if you want max throughput set the
>    max_sectors_kb value to the hw max. (you pay in terms of fairness for


There are two more factors that play into #1 and #5. Firstly there is a
per command completion overhead in ATA without NCQ being active and that
isn't yet a heavily optimised libata path. Secondly erase block size
matters with flash drives so the bigger each I/O the better erase block
behaviour we should get.

  parent reply	other threads:[~2007-02-13 11:15 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-12 14:02 SATA-performance: Linux vs. FreeBSD Martin A. Fink
2007-02-12 17:04 ` Andi Kleen
2007-02-12 16:27   ` Martin A. Fink
2007-02-12 18:41     ` Andi Kleen
2007-02-12 17:56       ` Martin A. Fink
2007-02-12 18:17         ` Ray Lee
2007-02-12 19:08         ` Alan
2007-02-12 20:34           ` Nigel Cunningham
2007-02-13  9:34           ` Martin A. Fink
2007-02-13 11:25             ` Alan
2007-02-13 12:32               ` Martin A. Fink
2007-02-13 14:47                 ` Theodore Tso
2007-02-13 15:03                   ` Alan
2007-02-13 17:12               ` Jeff Garzik
2007-02-12 23:31         ` Matthias Schniedermeyer
2007-02-13  9:25           ` Martin A. Fink
2007-02-13 10:08             ` Arjan van de Ven
2007-02-13 11:18               ` Andi Kleen
2007-02-13 10:25                 ` Arjan van de Ven
2007-02-13 11:27               ` Alan [this message]
2007-02-13 11:59                 ` Jörn Engel
2007-02-13 19:54               ` Jeffrey Hundstad
2007-02-13 10:16             ` Matthias Schniedermeyer
2007-02-13 10:29               ` Martin A. Fink
2007-02-13 12:04                 ` Jörn Engel
2007-02-13 12:24                 ` Matthias Schniedermeyer
2007-02-13 12:49                   ` Martin A. Fink
2007-02-13 13:53                     ` Matthias Schniedermeyer
2007-02-12 16:37   ` Martin A. Fink
2007-02-12 18:19     ` Stefan Richter
2007-02-13 19:09     ` Jeff Carr
2007-02-12 17:42   ` Martin A. Fink
2007-02-15  5:48 ` Tejun Heo

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