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Date: Mon, 4 Jan 2010 14:28:49 -0800
From: Greg Lewis <glewis@eyesbeyond.com>
To: Dino Vliet <dino_vliet@yahoo.com>
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Cc: simon@olofsson.de, glewis@freebsd.org, freebsd-questions@freebsd.org
Subject: Re: tweak FreeBSD 8 for optimal java/weka performance
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On Mon, Jan 04, 2010 at 06:54:22AM -0800, Dino Vliet wrote:
> Dear freebsd people,
> ?
> in a few days I will install freebsd 8.0 amd64 on my 8GB RAM dual core
> machine and use the system as a application server. I will install
> the /usr/ports/textproc/weka toolkit, a program written in java. I
> will use the diablo jdk port in /usr/ports/java.
> ?
> Due to the nature of the research I will be doing I will need to max
> out my machine for optimal java performance. For example, I will use
> the?-Xmx7g flag frequently to set?the maximun java heap size?to 7GB.
> ?
> Are there any other tweaks I should think of to get as much RAM for
> my java programs?
> Like building custom and small kernel, in order to minimize te size
> of the kernel?
> ?

I'd recommend using openjdk6 instead of Diablo if you want to maximise
performance.  Diablo is getting old and isn't available natively for 8.x
(its runs as a compatible binary with the compat7x port installed).

IIRC there is an option to tell the JVM to use as much RAM as possible,
but I don't recall it off the top of my head.  There should be some docs
on this on the main Java site at Sun and they will be equally relevant to
FreeBSD as they are to any other OS.

-- 
Greg Lewis                          Email   : glewis@eyesbeyond.com
Eyes Beyond                         Web     : http://www.eyesbeyond.com
Information Technology              FreeBSD : glewis@FreeBSD.org