tweak FreeBSD 8 for optimal java/weka performance

Dino Vliet dino_vliet at
Tue Jan 5 13:43:41 UTC 2010

--- On Mon, 1/4/10, Greg Lewis <glewis at> wrote:

From: Greg Lewis <glewis at>
Subject: Re: tweak FreeBSD 8 for optimal java/weka performance
To: "Dino Vliet" <dino_vliet at>
Cc: freebsd-questions at, glewis at, simon at
Date: Monday, January 4, 2010, 11:28 PM

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 at
Eyes Beyond                         Web     :
Information Technology              FreeBSD : glewis at
Thanks for the advice, but isn't weka depandent on diablo-jdk-, so I guess I'll have to do something (change makefile to what?) before I install weka? 


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