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Re: [Jfs-discussion] benchmark results

To: Larry McVoy <lm@xxxxxxxxxxxx>, tytso@xxxxxxx, Christian Kujau <lists@xxxxxxxxxxxxxxx>, jim owens <jowens@xxxxxx>, jfs-discussion@xxxxxxxxxxxxxxxxxxxxx, linux-nilfs@xxxxxxxxxxxxxxx, xfs@xxxxxxxxxxx, reiserfs-devel@xxxxxxxxxxxxxxx, Peter Grandi <pg_jf2@xxxxxxxxxxxxxxxxxx>, ext-users <ext3-users@xxxxxxxxxx>, linux-ext4@xxxxxxxxxxxxxxx, linux-btrfs@xxxxxxxxxxxxxxx
Subject: Re: [Jfs-discussion] benchmark results
From: Edward Shishkin <edward.shishkin@xxxxxxxxx>
Date: Fri, 15 Jan 2010 22:42:38 +0100
In-reply-to: <20091228140855.GD10982@xxxxxxxxxxxx>
References: <20091224212756.GM21594@xxxxxxxxx> <alpine.DEB.2.01.0912241739160.3483@xxxxxxxxxxxxxxxxxx> <20091225161453.GD32757@xxxxxxxxx> <20091225162238.GB19303@xxxxxxxxxxxx> <alpine.DEB.2.01.0912251042540.3483@xxxxxxxxxxxxxxxxxx> <4B36333B.3030600@xxxxxx> <4B365EBE.5050804@xxxxxxxxxxxxxxx> <4B37BA76.7050403@xxxxxx> <alpine.DEB.2.01.0912271346240.3483@xxxxxxxxxxxxxxxxxx> <20091227223307.GA4429@xxxxxxxxx> <20091228140855.GD10982@xxxxxxxxxxxx>
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When things didn't match up that was a clue that either

    - the benchmark was broken
    - the code was broken
[...]

I would carry out an object-oriented dualism here.


[1] methods (kernel module) ---- [2] objects (formatted partition)

|                                |
|                                |

[3] benchmarks ----------------- [4] user-space utilities (fsck)


User-space utilities investigate "object corruptions",
whereas benchmarks investigate "software corruptions"
(including bugs in source code, broken design, etc, etc..)

It is clear that "software" can be "corrupted" by a larger
number of ways than "objects". Indeed, it is known that
dual space V* (of all linear functions over V) is a much
more complex object than V.

So benchmark is a process which takes a set of methods
(we consider only "software" benchmarks) and puts numerical
values populated with a special (the worst) value CRASH.

Three main categories of benchmarks using:

1) Internal testing

An engineer makes optimizations in a file system (e.g. for a
customer) via choosing functions or plugins as winners in
a set of internal (local) "nominations".

2) Business plans

A system administrator chooses a "winner" in some (global)
"nomination" of file systems in accordance with internal
business-plans.

3) Flame and politics

Someone presents a "nomination" (usually with the "winner"
among restricted number of nominated members) to the public
while nobody asked him to do it.

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