From owner-freebsd-hackers@FreeBSD.ORG Fri Apr 2 04:25:39 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CCD0716A4CF for ; Fri, 2 Apr 2004 04:25:39 -0800 (PST) Received: from mizar.origin-it.net (mizar.origin-it.net [194.8.96.234]) by mx1.FreeBSD.org (Postfix) with ESMTP id EDBDC43D31 for ; Fri, 2 Apr 2004 04:25:38 -0800 (PST) (envelope-from helge.oldach@atosorigin.com) Received: from matar.hbg.de.int.atosorigin.com (dehsfw3e.origin-it.net [194.8.96.68])i32CPb6W068695 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 2 Apr 2004 14:25:37 +0200 (CEST) (envelope-from helge.oldach@atosorigin.com) Received: from galaxy.hbg.de.ao-srv.com (galaxy.hbg.de.ao-srv.com [161.89.20.4])ESMTP id i32CPbNJ004261; Fri, 2 Apr 2004 14:25:37 +0200 (CEST) (envelope-from helge.oldach@atosorigin.com) Received: (from hmo@localhost) by galaxy.hbg.de.ao-srv.com (8.9.3p2/8.9.3/hmo30mar03) id OAA28162; Fri, 2 Apr 2004 14:25:35 +0200 (MET DST) Message-Id: <200404021225.OAA28162@galaxy.hbg.de.ao-srv.com> In-Reply-To: <200404011829.04221.thierry@herbelot.com> from Thierry Herbelot at "Apr 1, 2004 6:29: 4 pm" To: thierry@herbelot.com Date: Fri, 2 Apr 2004 14:25:35 +0200 (MET DST) From: Helge Oldach X-Address: Atos Origin GmbH, Friesenstraße 13, D-20097 Hamburg, Germany X-Phone: +49 40 7886 7464, Fax: +49 40 7886 9464, Mobile: +49 160 4782517 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit cc: freebsd-hackers@freebsd.org cc: bzeeb-lists@lists.zabbadoz.net Subject: Re: implications of SMP kernel on UP X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Apr 2004 12:25:39 -0000 Thierry Herbelot: >Le Thursday 01 April 2004 09:10, Bjoern A. Zeeb a écrit : >> what are the implications on running an SMP enabled kernel on a UP >> machine ? >> >> I first thought of things like: >> - performence (most likely not worth the discussion ?) > >I got an improvement with a factor of ten between an SMP and a UP >kernel on a HTT-enabled P4/2,6GHz/800MHz FSB on network transfers (with >gigabit Ethernet boards: SMP gives about 6MB/s for FTP transfer rate, >and UP gives up to 75MB/s) > >So: as long as the network stack is not fully locked (this is coming - >perhaps for 5.3), a server should definitely run a UP kernel. Ooops, that is indeed dramatic. Does the same locking impact also affect other, interrupt-bound subsystems, such as the disk subsystem (in particular SCSI)? I am asking because I have a HTT machine that walks some 35.000 files every few minutes with an aggreated disk I/O load of only 5 MBytes/second, while the SCSI hardware is able to do SCSI-3/160... It appears that a lot of processes are indeed disk bound ("D"). Helge