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Date: Mon, 16 Jul 2001 05:10:46 +1200
From: Chris Wedgwood <cw@f00f.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andrew Morton <andrewm@uow.edu.au>,
        Andreas Dilger <adilger@turbolinux.com>,
        "Albert D. Cahalan" <acahalan@cs.uml.edu>,
        Ben LaHaise <bcrl@redhat.com>,
        Ragnar Kjxrstad <kernel@ragnark.vestdata.no>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        mike@bigstorage.com, kevin@bigstorage.com, linux-lvm@sistina.com
Subject: Re: [PATCH] 64 bit scsi read/write
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On Sat, Jul 14, 2001 at 09:45:44AM +0100, Alan Cox wrote:

    As far as I can tell none of them at least in the IDE world

Can you test with the code I posted a hour or so ago please?

I ask this because I tested writes to:

  -- buffered devices

  -- ide with caching on

  -- ide with caching off

  -- scsi (caching on?)

To a buffered device, I get something silly like 63000
writes/second. No big surprises there (other than Linux is bloody lean
these days).

To a SCSI device (10K RPM SCSI-3 160 drive), I get something like 167
writes/second, which seems moderately sane if caching is disabled.

To a cheap IDE drive (5400 RPM?) with caching off, I get about 87
writes/second.

To the same drive, with caching on, I get almost 4000 writes/second.

This seems to imply, at least for my test IDE drive, you can turn
caching off --- and its about half as fast as my SCSI drives which
rotate at about twice the speed (sanity check).

IDE drive:  IBM-DTTA-351010, ATA DISK drive
SCSI drive: SEAGATE ST318404LC




   --cw


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