Date: Fri, 9 Jan 2004 11:44:37 -0800
From: Andrew Morton <akpm@osdl.org>
To: Ram Pai <linuxram@us.ibm.com>
Cc: ornati@lycos.it, gandalf@wlug.westbo.se, linux-kernel@vger.kernel.org
Subject: Re: Strange IDE performance change in 2.6.1-rc1 (again)
Message-Id: <20040109114437.550fa5f4.akpm@osdl.org>
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Ram Pai <linuxram@us.ibm.com> wrote:
>
> 1) see whether you see a regression with files replacing the 
>     cat command in your script with
>         dd if=big_file of=/dev/null bs=1M count=256

You'll need to unmount and remount the fs in between to remove the file
from pagecache.  Or use fadvise() to remove the pagecache.  There's a
little tool which does that in 

http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz

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