From: Andrew Morton <akpm@osdl.org>
To: jlnance@unity.ncsu.edu
Cc: linux-kernel@vger.kernel.org
Subject: Re: Test program with VM or FS problems
Date: Sat, 20 Dec 2003 08:03:27 -0800 [thread overview]
Message-ID: <20031220080327.2aef4c11.akpm@osdl.org> (raw)
In-Reply-To: <20031220154315.GA12763@ncsu.edu>
jlnance@unity.ncsu.edu wrote:
>
> Hello Andrew,
> About a year ago I told you I would get you some more information
> about a problem I was seeing that might be in the Linux VM or ext{2,3}
> code.
I thought you'd forgotten!
> For most of the run the temp file is smaller
> than this. So for most of the run both files will fit into the
> memory of the machine. Thus I would expect the program to run
> quickly, because it will not need to touch the disk. Things are
> in cache. This is not what I see. Instead the program seems to
> be very much disk bound.
I bet the use-once page replacement heuristic is doing the wrong thing. I
noticed it playing up once - the machine had 30M on the inactive list and
reading a 40M file repeatedly caused that file to never get cached. it
just kept on reclaiming itself.
next prev parent reply other threads:[~2003-12-20 16:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-20 15:43 jlnance
2003-12-20 16:03 ` Andrew Morton [this message]
2003-12-21 0:54 ` Rik van Riel
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