From owner-freebsd-questions Fri Nov 2 21:51:16 2001 Delivered-To: freebsd-questions@freebsd.org Received: from dv-db.com (dv-db.com [207.159.141.95]) by hub.freebsd.org (Postfix) with ESMTP id 87BCA37B40A for ; Fri, 2 Nov 2001 21:51:13 -0800 (PST) Received: from mark2 (host217-35-43-63.in-addr.btopenworld.com [217.35.43.63]) by dv-db.com (8.9.3/8.9.3) with SMTP id FAA03098; Sat, 3 Nov 2001 05:51:07 GMT Message-ID: <006101c1642b$57af4480$0200a8c0@mark2> From: "Mark Hughes" To: "Andrew C. Hornback" , References: <000701c1642a$11a7d3e0$6600000a@columbia> Subject: Re: SMP kernel with 1 processor.... Date: Sat, 3 Nov 2001 05:49:13 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > > So, is it okay to compile a kernel with the following options uncommented, > > and will it impact performance at all to do so: > > > > # To make an SMP kernel, the next two are needed > > #options SMP # Symmetric MultiProcessor Kernel > > #options APIC_IO # Symmetric (APIC) I/O > > > > Also, other than these two options, is there anything else that > > needs to be > > enabled/disabled to work with SMP? > > No, that'll set it up as SMP, but I don't think you want to do that. I'm > not aware of the hazards of doing such, but I don't think it's a "best > practice". right. > Also, how long is it going to take to install a second processor and do a > kernel recompile? You've gotta take the machine fully off-line and powered > down to add the second proc (unless you're running hardware that allows hot > swap of processors, which would be REALLY cool)... indeed it would... if only :-) > And even then, you could compile the SMP kernel and leave it sitting on the > machine, run it on a single proc kernel, and switch it over once you've got > the second processor in. this is true, and sounds like a good idea. So, other than those two lines in the kernel config, is there anything else that one needs to change in order to enable the use of two processors? Thanks, Mark To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message