From owner-freebsd-current@FreeBSD.ORG Thu Apr 12 10:46:30 2007 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 47C3416A405 for ; Thu, 12 Apr 2007 10:46:30 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.freebsd.org (Postfix) with ESMTP id 05B3013C4BF for ; Thu, 12 Apr 2007 10:46:29 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 81D1A46B60; Thu, 12 Apr 2007 06:46:29 -0400 (EDT) Date: Thu, 12 Apr 2007 11:46:29 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Randall Stewart In-Reply-To: <461E0078.3050001@cisco.com> Message-ID: <20070412114344.G64803@fledge.watson.org> References: <461E0078.3050001@cisco.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-current@freebsd.org, Brad Penoff , Janardhan Iyengar Subject: Re: CPU utilization X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Apr 2007 10:46:30 -0000 On Thu, 12 Apr 2007, Randall Stewart wrote: > I have probably an old question that has been asked.. but here goes anyway. > > I have three machines. > > 1) stewart - running 7.0 (2.8gig p4 dual core) > 2) bsd1 - running 7.0 (2.8gig Xeon Hyperthreaded) > 3) bsd2 - running 6.2 (2.4gig Xeon Hyperthreaded) > > Now if I run tests that max out cpu (at least I think they do).. I see <1> > or <2> drag down to 1% idle/ even 0 %idle. > > However <3> never drops below 50% idle.. it preforms a lot slower too.. > which I expect since it is somewhat of an older processor.. but in running > say top -S It strikes me that there are two possibilities here, and it could be both are true: (1) In 7.x, there are scheduling and accounting changes that could result in both better utilization and different measurement. (2) In 7.x, certain debugging features default to on (WITNESS, INVARIANTS, user space malloc debugging) that add significant (!) overhead. I'd confirm first that (2) isn't the cause of the change -- make sure you have a kernel without debugging features turned on, and change the man page on malloc.conf to make sure user debugging is turned off for malloc. Then let's revisit (1). Robert N M Watson Computer Laboratory University of Cambridge > > I see CPU 1 always running the idle process... > > Is this an accounting error that is being seen? aka top > does not know how to display things .. or is this a > scheduling error.. i.e.. move to 7.0 and life will > be better :-D > > Thanks > > R > -- > Randall Stewart > NSSTG - Cisco Systems Inc. > 803-345-0369 803-317-4952 (cell) > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >