From owner-freebsd-current@FreeBSD.ORG  Tue May 20 02:52:08 2003
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To: Heiko Schaefer <hschaefer@fto.de>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Tue, 20 May 2003 11:08:07 +0200."
             <20030520105030.U60060@daneel.foundation.hs> 
Date: Tue, 20 May 2003 11:52:03 +0200
Message-ID: <31414.1053424323@critter.freebsd.dk>
cc: current@freebsd.org
Subject: Re: gbde performance question 
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In message <20030520105030.U60060@daneel.foundation.hs>, Heiko Schaefer writes:

>i figure this is the amount of cpu time that is used by raw number
>crunching (and for example does not include disk-io or anything of that
>sort). that would mean that ~1/3 of my cpu can do ~8 MB/s of gbde's
>crypto. if so, i could estimate that gbde can theoretically process
>roughly 25MB/s on this athlon 1800+.
>
>that looks like an rather low number to me. sites such as
>
>http://www.tcs.hut.fi/~helger/aes/rijndael.html
>
>suggest that on a cpu of that speed, memory bandwidth should be the
>limiting factor when using AES/Rijndael.
>
>am i overlooking something ?!

Make sure you use as large as possible a sectorisize on your
GBDE devices, you set this with "gbde init /dev/bla -i", this
does affect your performance a fair bit.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.