From owner-freebsd-net@FreeBSD.ORG Tue Jan 8 15:57:09 2013 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 9F38470A for ; Tue, 8 Jan 2013 15:57:09 +0000 (UTC) (envelope-from yanegomi@gmail.com) Received: from mail-pa0-f46.google.com (mail-pa0-f46.google.com [209.85.220.46]) by mx1.freebsd.org (Postfix) with ESMTP id 7E0929E2 for ; Tue, 8 Jan 2013 15:57:09 +0000 (UTC) Received: by mail-pa0-f46.google.com with SMTP id bh2so408072pad.5 for ; Tue, 08 Jan 2013 07:57:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:subject:mime-version:content-type:from:in-reply-to:date :cc:content-transfer-encoding:message-id:references:to:x-mailer; bh=IY/p7SCZr2j+chvaaN6Ws4GyRSeMhL8dZGXjBrqcljY=; b=XkG7Cv72vgYxYQLI/rChYsCg6TozQMWf8tQYWw9u0vuuDVZydLAl4lj+ptF9TpRuSt g2XX6KnhpKC4FmQv12TGlhHtz6fhV9fLbL1s9LB65y9ppjRd5PRIywJfKU3Q8odnvA/R UZMgbBWcwUoStAt5zPsQSgvoZV3Hi36GxGLDF++aYiIexcwIOz5QDvsNxlHucMQpjGZN zOtbC0LeU8vSJFz25uO3OGaWmsh11XpKwhNCHN3RxvKUh3k4JgWHqxVpC425kn2KIHga f7o2MbYJ2E5t4zv/n4VpUnUVzAAAsMljkf+QAN50Vo+hjXQUI62KRpB4YpD8fvDOpMTP tV7A== X-Received: by 10.68.192.97 with SMTP id hf1mr199323505pbc.106.1357660628753; Tue, 08 Jan 2013 07:57:08 -0800 (PST) Received: from [192.168.20.11] (c-24-19-191-56.hsd1.wa.comcast.net. [24.19.191.56]) by mx.google.com with ESMTPS id oi3sm39849448pbb.1.2013.01.08.07.57.06 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 08 Jan 2013 07:57:06 -0800 (PST) Subject: Re: To SMP or not to SMP Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=us-ascii From: Garrett Cooper In-Reply-To: <1357660252.29936.YahooMailClassic@web121603.mail.ne1.yahoo.com> Date: Tue, 8 Jan 2013 07:57:04 -0800 Content-Transfer-Encoding: quoted-printable Message-Id: References: <1357660252.29936.YahooMailClassic@web121603.mail.ne1.yahoo.com> To: Barney Cordoba X-Mailer: Apple Mail (2.1283) Cc: freebsd-net@freebsd.org, Erich Dollansky X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Jan 2013 15:57:09 -0000 On Jan 8, 2013, at 7:50 AM, Barney Cordoba wrote: > --- On Mon, 1/7/13, Erich Dollansky = wrote: >=20 >> From: Erich Dollansky >> Subject: Re: To SMP or not to SMP >> To: "Barney Cordoba" >> Cc: freebsd-net@freebsd.org >> Date: Monday, January 7, 2013, 10:56 PM >> Hi, >>=20 >> On Mon, 7 Jan 2013 18:25:58 -0800 (PST) >> Barney Cordoba >> wrote: >>=20 >>> I have a situation where I have to run 9.1 on an old >> single core box. >>> Does anyone have a handle on whether it's better to >> build a non SMP >>> kernel or to just use a standard SMP build with just >> the one core? >>> Thanks. >>=20 >> I ran a single CPU version of FreeBSD until my last single >> CPU got hit >> by a lightning last April or May without any problems. >>=20 >> I never saw a reason to include the overhead of SMP for this >> kind of >> machine and I also never ran into problems with this. >=20 > Another "ass"umption based on logic rather than empirical evidence. It isn't really an offhanded assumption because there _is_ = additional overhead added into the kernel structures to make things work = SMP with locking :). Whether or not it's measurable for you and your = applications, I have no idea. HTH, -Garrett=