From owner-freebsd-stable@FreeBSD.ORG Tue Nov 4 04:52:24 2003 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 13C9A16A4CE for ; Tue, 4 Nov 2003 04:52:24 -0800 (PST) Received: from mizar.origin-it.net (mizar.origin-it.net [194.8.96.234]) by mx1.FreeBSD.org (Postfix) with ESMTP id 788A643FD7 for ; Tue, 4 Nov 2003 04:52:22 -0800 (PST) (envelope-from helge.oldach@atosorigin.com) Received: from matar.hbg.de.int.atosorigin.com (dehsfw3e.origin-it.net [194.8.96.68])hA4CqKUQ088816 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 4 Nov 2003 13:52:20 +0100 (CET) (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 hA4CqJ35084346; Tue, 4 Nov 2003 13:52:20 +0100 (CET) (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 NAA03072; Tue, 4 Nov 2003 13:52:16 +0100 (MET) Message-Id: <200311041252.NAA03072@galaxy.hbg.de.ao-srv.com> In-Reply-To: <200311040957.hA49vGD2070104@lurza.secnetix.de> from Oliver Fromme at "Nov 4, 2003 10:57:16 am" To: olli@lurza.secnetix.de (Oliver Fromme) Date: Tue, 4 Nov 2003 13:52:15 +0100 (MET) 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=US-ASCII Content-Transfer-Encoding: 7bit cc: freebsd-stable@freebsd.org Subject: Re: [4.9-RC] What happened to ``options HTT'' ? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Nov 2003 12:52:24 -0000 Oliver Fromme: >Brooks Davis wrote: > > On Tue, Oct 28, 2003 at 11:42:57PM +0200, Jaco van Tonder wrote: > > > I just cvsup'ed to that latest -STABLE and saw that option HTT > > > is no longer availible in LINT. Does anyone know why this is no > > > longer supported? I searched the stable@ list but cant seem to > > > find anything on this. > > It is no longer necessicary as HTT logical CPUs are now > > activated by default. If you wish to use them, set the sysctl > > machdep.hlt_logical_cpus to 0. >Can that sysctl be changed at runtime, or is it only possible to do it >in the loader? The UPDATING entry isn't completely clear about that. I can confirm from experience that changing this sysctl to 0 immediately started the second logical CPU. Turning it back to 1 apparently stops processes on the second logical CPU to start, instead everything runs on CPU0. However processes running on the second CPU remain there until they terminate. >By the way, are there any "real world" experiences whether it's worth >it to use the logical CPUs, say, on a PostgreSQL or Apache server, or >with Java stuff (jakarta/tomcat etc.)? That would interest me as well. In particular I would be interested where improvements might be expected - in CPU-intensive environments, interrupt-intensive enviroments, and I/O-intensive environments. I am running a system that walks a couple of thousand files every minute - would that benefit from HTT? (I seem to recall that UFS as part of the kernel is restricted to a single CPU?) Helge