From owner-freebsd-current Tue Jan 28 11:23:52 2003 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 83E8637B401 for ; Tue, 28 Jan 2003 11:23:50 -0800 (PST) Received: from garple.migus.org (pcp243391pcs.howard01.md.comcast.net [68.55.83.143]) by mx1.FreeBSD.org (Postfix) with ESMTP id D4E1943F3F for ; Tue, 28 Jan 2003 11:23:49 -0800 (PST) (envelope-from adam@migus.org) Received: from migus.org (xwcdl89sjoqa0bnl@garple.migus.org [192.168.4.4]) by garple.migus.org (8.12.6/8.12.6) with SMTP id h0SJNmVq040268; Tue, 28 Jan 2003 14:23:48 -0500 (EST) (envelope-from adam@migus.org) Received: from 192.168.4.2 (SquirrelMail authenticated user adam) by mail.migus.org with HTTP; Tue, 28 Jan 2003 14:23:48 -0500 (EST) Message-ID: <49567.192.168.4.2.1043781828.squirrel@mail.migus.org> Date: Tue, 28 Jan 2003 14:23:48 -0500 (EST) Subject: Re: Force 1 CPU on SMP kernel? From: "Adam Migus" To: X-Priority: 3 Importance: Normal Cc: , X-Mailer: SquirrelMail (version 1.2.8) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=-3.4 required=5.7 tests=AWL,QUOTED_EMAIL_TEXT,SPAM_PHRASE_00_01 version=2.41 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > > > On Tue, 28 Jan 2003, Adam Migus wrote: > >> Yes, just to be more explicit. What I want to do is get >> the >> 'real' difference a second processor makes. ie. If I run >> GENERIC I'm not incurring the overhead associated with >> SMP/APIC. >> I want to use the same kernel making as small a change as >> nessessary to have the machine start/use just one CPU. > > I'm not aware of any hacks to disable APs through > loader.conf. > If you're trying to benchmark the system's performance with > 1 > vs N CPUs, you're best off pulling all but the BSP CPU out > of > the machine. For such a benchmark to be accurate, you > shouldn't make any software changes (kernel, daemons or > startup configs). I tend to agree but things like warrenties and flakey boards preclude removal of CPU(s). All the same I think the ability to turn on/off AP's at boot would be useful in general. -- Adam Migus - Research Scientist Network Associates Laboratories (http://www.nailabs.com) TrustedBSD (http://www.trustedbsd.org) FreeBSD (http://www.freebsd.org) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message