From owner-freebsd-questions  Wed May 16  6: 4:29 2001
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Date: Wed, 16 May 2001 15:04:11 +0200
From: Michael Schuster <michael.schuster@sun.com>
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To: dleimbac@earthlink.net
Cc: questions@FreeBSD.ORG, arch@FreeBSD.ORG
Subject: Re: python fork call raised my load over 400!
References: <200105161254.FAA14005@scaup.mail.pas.earthlink.net>
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dave wrote:
> 
> If you have a block of free time today check this out!
> 
> I keyed this in interactively with Python <it wasn't a file>
> ----SNIP--------
> 
> import os
> 
> while 1:
>         os.fork()
> -----SNIP-------

this is a classical fork bomb, and the system behaved very much as
designed. If you're using this to compare Linux to FreeBSD, you'd better
reconsider and get yourself proper benchmarks.

btw: pls. don't cross-post, questions is quite enough.


> This user run program brought my system to a load of 419 with the system
> using
> 94% of the resources and 500 user processes on my AMD Duron 800 box with
> 256MB RAM...

of course: every new process needs resources, and as new processes get more
CPU share than older ones, the newly forked processes would immediately
fork again.
 
> I don't know that the processor/RAM is relevant but I could not fork
> anymore!

of course you couldn't, you completely filled up your machine are were
still doing so - getting a word in egdeways was impossible.
 
> My ultimate question is ... should I be comparing FreeBSD to Linux?
> Does it really matter if Linux is performing better or worse than FreeBSD?

see above - this about the worst type of "benchmark" I've ever seen.

> Still  a user process probably shouldn't be able to hose the whole system
> IMHO.

sorry, that's the way Unix's fair-share scheduler works.
 
for more details, look into "Design and Implementation of 4.4 BSD"

HTH
Michael
-- 
Michael Schuster          / Michael.Schuster@sun.com
Sun Microsystems GmbH     / (+49 89) 46008-2974 | x62974
Sonnenallee 1, D-85551 Kirchheim-Heimstetten

Recursion, n.: see 'Recursion'

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