Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 20 Jan 2009 15:56:38 +0000 (GMT)
From:      Robert Watson <rwatson@FreeBSD.org>
To:        Barney Cordoba <barney_cordoba@yahoo.com>
Cc:        freebsd-current@freebsd.org
Subject:   Re: Running on only some cores
Message-ID:  <alpine.BSF.2.00.0901201554320.74507@fledge.watson.org>
In-Reply-To: <844890.15272.qm@web63902.mail.re1.yahoo.com>
References:  <844890.15272.qm@web63902.mail.re1.yahoo.com>

next in thread | previous in thread | raw e-mail | index | archive | help

On Tue, 20 Jan 2009, Barney Cordoba wrote:

> Can FreeBSD be configured to only run on N cores? So for example, if I have 
> an 8 core system, can it be configured in loader.conf or through a simple 
> hack to only run on 2 cores?
>
> We're testing various configs, and its not terribly convenient to keep 
> swapping out CPUs.

You can use device.hints to disable specific CPUs using:

   hint.lapic.X.disabled=1

This prevents FreeBSD from probing the CPU.  If I had to guess, disabling the 
BSP would be a bad idea, but for the APs it should work fine. :-)

Robert N M Watson
Computer Laboratory
University of Cambridge



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?alpine.BSF.2.00.0901201554320.74507>