From owner-freebsd-current@FreeBSD.ORG Mon Jul 7 06:55:04 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1AE5D37B404 for ; Mon, 7 Jul 2003 06:55:04 -0700 (PDT) Received: from krusty.dt.e-technik.uni-dortmund.de (mail.dt.E-Technik.Uni-Dortmund.DE [129.217.163.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id 557FB43F3F for ; Mon, 7 Jul 2003 06:55:03 -0700 (PDT) (envelope-from matthias.andree@gmx.de) Received: from m2a2.dyndns.org (krusty.dt.e-technik.uni-dortmund.de [129.217.163.1])47560A381D for ; Mon, 7 Jul 2003 15:55:02 +0200 (CEST) Received: by merlin.emma.line.org (Postfix, from userid 500) id 500818405B; Mon, 7 Jul 2003 15:54:59 +0200 (CEST) Date: Mon, 7 Jul 2003 15:54:59 +0200 From: Matthias Andree To: current@freebsd.org Message-ID: <20030707135459.GH10021@merlin.emma.line.org> Mail-Followup-To: current@freebsd.org References: <3F08B199.3050409@comcast.net> <3F08B79B.2040805@gmx.net> <20030707001443.GA1530@invisible-island.net> <20030707002347.GC5141@aurema.com> <20030706203440.D89894@vhost101.his.com> <3F08C4FD.8010107@gmx.net> <3F09663D.9020200@gmx.net> <20030707123707.GA18750@saltmine.radix.net> <3F097719.8030301@gmx.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3F097719.8030301@gmx.net> User-Agent: Mutt/1.5.4i Subject: Re: /dev/shm X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 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: Mon, 07 Jul 2003 13:55:04 -0000 On Mon, 07 Jul 2003, Marcin Dalecki wrote: > The point is that this is one of the reasons why the top command in > question takes a lot of relative CPU time under Linux. Some > "faster" versions of procps utils try to cache data but the trade off > is simply the fact that the results are not 100% accurate. Top data is not accurate (I though that was obvious ;-). It's an obsolete snapshot the very moment it's printed to your console, and I bet it changes as you read with a lot of implementations because no-one wants to beat the big kernel lock on the process list just because some user happens to run top, might be a nice DoS otherwise, fork-bombing top... If you want accurate data, use a kernel debugger with remote interface and make sure the machine does nothing except servicing the debugger interface. > I tought this was obvious? Why do I care? 0.58user 0.89system 1:00.91elapsed 2%CPU -- on a 266 MHz Pentium-II, Linux 2.4, 5 years old, with 190 processes. The box idles 73% of the time it's up, there's _ample_ CPU power left. -- Matthias Andree