Message-ID: <4069B6F8.1020506@techsource.com>
Date: Tue, 30 Mar 2004 13:05:44 -0500
From: Timothy Miller <miller@techsource.com>
MIME-Version: 1.0
To: Jens Axboe <axboe@suse.de>
CC: Jeff Garzik <jgarzik@pobox.com>, Andrea Arcangeli <andrea@suse.de>,
       Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>,
       William Lee Irwin III <wli@holomorphy.com>,
       Nick Piggin <nickpiggin@yahoo.com.au>, linux-ide@vger.kernel.org,
       Linux Kernel <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH] speed up SATA
References: <4066021A.20308@pobox.com> <200403282030.11743.bzolnier@elka.pw.edu.pl> <20040328183010.GQ24370@suse.de> <200403282045.07246.bzolnier@elka.pw.edu.pl> <406720A7.1050501@pobox.com> <20040329005502.GG3039@dualathlon.random> <40679FE3.3080007@pobox.com> <20040329130410.GH3039@dualathlon.random> <40687CF0.3040206@pobox.com> <20040330110928.GR24370@suse.de>
In-Reply-To: <20040330110928.GR24370@suse.de>
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Jens Axboe wrote:

> - The optimal_sectors calculation is just an average of previous maximum
>   with current maximum. The scheme has a number of break down points,
>   for instance writes starving reads will give you a bad read execution
>   time, further limiting ->optimal_sectors[READ]


I did look through your code a bit, but one thing to be concerned with 
is that going only on max throughput might be fooled by cache hits on 
the drive.

-
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