From owner-freebsd-stable@FreeBSD.ORG Thu Aug 24 19:00:39 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org 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 AEF0416A4DD for ; Thu, 24 Aug 2006 19:00:39 +0000 (UTC) (envelope-from josh@tcbug.org) Received: from rwcrmhc11.comcast.net (rwcrmhc11.comcast.net [204.127.192.81]) by mx1.FreeBSD.org (Postfix) with ESMTP id 50C2143D4C for ; Thu, 24 Aug 2006 19:00:38 +0000 (GMT) (envelope-from josh@tcbug.org) Received: from gimpy (c-24-118-173-219.hsd1.mn.comcast.net[24.118.173.219]) by comcast.net (rwcrmhc11) with ESMTP id <20060824190034m110030bjqe>; Thu, 24 Aug 2006 19:00:38 +0000 From: Josh Paetzel To: freebsd-stable@freebsd.org Date: Thu, 24 Aug 2006 14:00:29 -0500 User-Agent: KMail/1.9.1 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200608241400.29903.josh@tcbug.org> Cc: Laurent C Subject: Re: [AMD64-SMP] I can't get my cpus working at 100% X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Aug 2006 19:00:39 -0000 On Thursday 24 August 2006 13:09, Laurent C wrote: > Hello all, > > I can't get my athlon x2 processor working at 100% on cpu-intensive > apps. I've made some tests with "john --test" and "transcode", wich > are both multithreaded apps. > > For example if I launch transcode it takes between 50% and 55% cpu > (on top), and if I launch > a second transcode session on another file, the total cpu used on > top is 100%, without lower the speed > of the first transcode session. > > The same behavior occurs with john. A single "john --test" give me > some speed results, and the same > command with a transcode or second "john --test" give me the same > speed results but now with 100% > cpu used. > > I made a "portupgrade -auf" just after building and installing my > SMP kernel and World, to be sure all is up-to-date. > > So it's seems it's not a "top" output problem, but a real underuse > of the computing power. > > %uname -a > FreeBSD wks02.chez.oim 6.1-STABLE FreeBSD 6.1-STABLE #0: Thu Aug 17 > 18:47:31 CEST 2006 > laurent@wks02.chez.oim:/usr/obj/usr/src/sys/WKS02_SMP amd64 > > Does anyone could explain me what's happening with my system ? An application that is not written to take advantage of a multi-cpu system is unable to max out more than one CPU at a time. top isn't really SMP 'aware' so in a dual CPU system something that is using 50% of the CPU is in reality maxing one CPU. This is a bit over-simplified because the process will bounce between the two CPUs but it will never execute on more than one at a time. -- Thanks, Josh Paetzel