From owner-freebsd-current Tue Jan 28 3: 2:50 2003 Delivered-To: freebsd-current@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 931) id CEEDC37B401; Tue, 28 Jan 2003 03:02:48 -0800 (PST) Date: Tue, 28 Jan 2003 03:02:48 -0800 From: Juli Mallett To: Odhiambo Washington Cc: Ceri Davies , Adam Migus , current@FreeBSD.org Subject: Re: Force 1 CPU on SMP kernel? Message-ID: <20030128030248.B45041@FreeBSD.org> References: <49857.192.168.4.2.1043728382.squirrel@mail.migus.org> <20030128095107.GA2628@submonkey.net> <20030128095349.GK36536@ns2.wananchi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <20030128095349.GK36536@ns2.wananchi.com>; from wash@wananchi.com on Tue, Jan 28, 2003 at 12:53:49PM +0300 Organisation: The FreeBSD Project X-Alternate-Addresses: , , , , X-Towel: Yes X-LiveJournal: flata, jmallett X-Negacore: Yes 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 * De: Odhiambo Washington [ Data: 2003-01-28 ] [ Subjecte: Re: Force 1 CPU on SMP kernel? ] > * Ceri Davies [20030128 12:50]: wrote: > > On Mon, Jan 27, 2003 at 11:33:02PM -0500, Adam Migus wrote: > > > Hi, > > > I'm doing some performance analysis on FreeBSD. I would like to > > > be able to make an SMP kernel use only one CPU. Of course I > > > realize running GENERIC would only use 1 CPU but the concern is > > > that the overhead assoicated with SMP will skew the statistics. > > > So my question is what would be the 'best' way to make an SMP > > > kernel only start/use CPU0? > > > > Yank the others ? > > > > What about building two kernels, one SMP, the other non-SMP, then > just boot wheichever kernel you want? Doesn't it server same purpose? > Better than Ceri's idea ;) You're missing the point. He wants to boot only the bootstrap processor, none of the APs, but still be running an SMP kernel. I think checking how much overhead "SMP" and "APIC_IO" add is a noble goal, and throwing real SMP into the mix would be dumb. -- Juli Mallett AIM: BSDFlata -- IRC: juli on EFnet OpenDarwin, Mono, FreeBSD Developer ircd-hybrid Developer, EFnet addict FreeBSD on MIPS-Anything on FreeBSD To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message