Hypertherading

[Barney Cordoba]

--- On Wed, 5/6/09, pluknet <pluknet at gmail.com> wrote:

> From: pluknet <pluknet at gmail.com>
> Subject: Re: Hypertherading
> To: "Barney Cordoba" <barney_cordoba at yahoo.com>
> Cc: "Current at freebsd.org" <Current at freebsd.org>
> Date: Wednesday, May 6, 2009, 10:55 PM
> 2009/5/7 Barney Cordoba <barney_cordoba at yahoo.com>:
> >
> > I just got a shiny new nehalem box and it comes up
> with 16 processors with dual quads installed. Is there any
> benefit or should hyperthreading be disabled?
> >
> 
> Hi. There is a measurable win if hyperthreading is enabled
> [1].
> You can switch it off via machdep.hyperthreading_enabled
> loader tunable.
> 
> [1]
> http://lists.freebsd.org/pipermail/freebsd-stable/2009-January/047460.html
> 
> 
> -- 
> wbr,
> pluknet

I assume you mean hyperthreading-allowed?

I set 

sysctl -a | grep hyper

machdep.hyperthreading_allowed: 0


but it still launches 16 cpus. Is that expected? It doesn't seem correct.

Barney