Running on only some cores

[Barney Cordoba]

--- On Tue, 1/20/09, Christoph Mallon <christoph.mallon at gmx.de> wrote:

> From: Christoph Mallon <christoph.mallon at gmx.de>
> Subject: Re: Running on only some cores
> To: barney_cordoba at yahoo.com
> Cc: freebsd-current at freebsd.org
> Date: Tuesday, January 20, 2009, 6:25 AM
> Barney Cordoba schrieb:
> > 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.
> 
> man 4 smp
> look for machdep.hlt_cpus

Ok, I see this does something when run after boot. So there is no way to get the OS to simply not launch the CPU? We have something that reads the number of cpus, which doesn't seem to change.

Barney