From owner-freebsd-current@FreeBSD.ORG  Thu Jun 12 10:22:14 2003
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id 5220A37B404; Thu, 12 Jun 2003 10:22:14 -0700 (PDT)
Received: from misery.sdf.com (misery.sdf.com [207.200.153.226])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 5940143FBD; Thu, 12 Jun 2003 10:22:11 -0700 (PDT)
	(envelope-from tom@sdf.com)
Received: from tom (helo=localhost)
	by misery.sdf.com with local-esmtp (Exim 2.12 #1)
	id 19QU9q-0005Lo-00; Thu, 12 Jun 2003 08:38:34 -0700
Date: Thu, 12 Jun 2003 08:38:08 -0700 (PDT)
From: Tom Samplonius <tom@sdf.com>
To: Killing <killing@barrysworld.com>
In-Reply-To: <024201c330f4$e58fdcf0$7b07000a@int.mediasurface.com>
Message-ID: <Pine.BSF.4.05.10306120834480.2674-100000@misery.sdf.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
cc: freebsd-smp@freebsd.org
cc: freebsd-current@freebsd.org
Subject: Re: SMP in 5.1 cant deactivate hyperthreading
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 12 Jun 2003 17:22:14 -0000


On Thu, 12 Jun 2003, Killing wrote:

> ----- Original Message ----- 
> From: "Doug White" <dwhite@gumbysoft.com>
> > > sysctl machdep.hlt_logical_cpus:
> > > machdep.hlt_logical_cpus: 1
> > 
> > Halting them will still cause the CPUs to be detected. They just won't do
> > any useful work.
> 
> Yep but the issue is that all the core admin tools are unaware of this and
> hence include the virtual cores in idle calcs etc making load monitoring
> impossible without nasty cludges :(
> 
> So what's the way forward?
> 1. Dont just use halt have a compile or other directive to disable them?
> 2. Update all tools to be halt aware?
> 
> Personally I'd go with 2 all be it more work / ramifications on other 3rd party
> tools as it gives the benefit of also working when physical CPU's are halted.

  Well, hyperthreading can be disabled via a kernel directive, right?

> Which ever it needs someone to pick it up ASAP dont you think?

  Really?  What's the hurry?  FreeBSD 5.x isn't even bootable/installable
on a number of SMP machines yet (ex.  Dell Poweredge 6350).

>     Steve


Tom