From owner-freebsd-hackers@FreeBSD.ORG Thu Jun 3 06:10:27 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 43C9416A4CE for ; Thu, 3 Jun 2004 06:10:27 -0700 (PDT) Received: from multiplay.co.uk (www1.multiplay.co.uk [212.42.16.7]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9ABE343D48 for ; Thu, 3 Jun 2004 06:10:26 -0700 (PDT) (envelope-from killing@multiplay.co.uk) Received: from steven ([193.123.241.40]) by multiplay.co.uk (multiplay.co.uk [212.42.16.7]) (MDaemon.PRO.v7.1.0.R) with ESMTP id md50000259305.msg for ; Thu, 03 Jun 2004 14:07:15 +0100 Message-ID: <184b01c4496c$4ea3a6a0$7b07000a@int.mediasurface.com> From: "Steven Hartland" To: Date: Thu, 3 Jun 2004 14:11:39 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Spam-Processed: multiplay.co.uk, Thu, 03 Jun 2004 14:07:15 +0100 (not processed: message from valid local sender) X-MDRemoteIP: 193.123.241.40 X-Return-Path: killing@multiplay.co.uk X-MDaemon-Deliver-To: freebsd-hackers@freebsd.org X-MDAV-Processed: multiplay.co.uk, Thu, 03 Jun 2004 14:07:15 +0100 Subject: FreeBSD vs Linux cpu usage measurements 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: Thu, 03 Jun 2004 13:10:27 -0000 I've been trying to do a direct comparison of game server cpu usages across various OS. Our current primary OS is FreeBSD 5.X running a 200HZ kernel. Initial tests on a dual boot opteron showed Linux using 0% CPU for 32 player servers so I got suspicious. >From talking to people it appears that Linux only registers cpu usage on the click tick so if a process was scheduled on the previous tick but yielded before the current tick it would have 0% cpu usage. In and extreme case could mean a process using 90% cpu or more could still be show in top as using 0% This seemed to be extremely noticeable on a 2.4.15 kernel but the values seem to me "more" correct on 2.6.5 but I believe this will be entirely down to the increase from 100Hz in 2.4 -> 1000Hz in 2.6. Anyway that's the background now to the question. Is there a fundamental difference in the way that FreeBSD records process cpu usage as I've seen this behaviour while running FreeBSD ever. Steve ================================================ This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. In the event of misdirection, illegible or incomplete transmission please telephone (023) 8024 3137 or return the E.mail to postmaster@multiplay.co.uk.