From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945945AbXC3Ej2 (ORCPT ); Fri, 30 Mar 2007 00:39:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1945946AbXC3Ej2 (ORCPT ); Fri, 30 Mar 2007 00:39:28 -0400 Received: from wr-out-0506.google.com ([64.233.184.234]:16476 "EHLO wr-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945945AbXC3Ej0 (ORCPT ); Fri, 30 Mar 2007 00:39:26 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=af6cUn29814RhKXBAgh05G9QFwP+/7mnEPdGvRfM7qqUYTgeOB2DEM7dB3rkMG/l5GV5MjtkhgtXVcPATAFEkSWYBDzkJCdBr33uAO/qv/3cBHmBmywiQs0FUKVZ2StNW12WZZus6pf/NhZdRDRRDN0+BJcHjxXweojbCyzoq1g= Message-ID: <75b66ecd0703292139m371e023xc17b3124ef991919@mail.gmail.com> Date: Fri, 30 Mar 2007 00:39:23 -0400 From: "Lee Revell" To: "Elliott Johnson" Subject: Re: strange high system cpu usage. Cc: linux-kernel@vger.kernel.org In-Reply-To: <20070330035457.57A4124753@ws5-3.us4.outblaze.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20070330035457.57A4124753@ws5-3.us4.outblaze.com> X-Google-Sender-Auth: eca43daf6f0be0c4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 3/29/07, Elliott Johnson wrote: > >What problem are you trying to solve? IOW, how do you know it's not > >just an artifact of diferent load average calculation between 2.4 and > >2.6? > > > >Are you actually seeing reduced throughput/performance? Or are you > >just looking at load average? > > > >Lee > > Well the problem is apparent, we are having abnormally high cpu usage. It's about a > 20-40% performance hit. > Please post a kernel profile for the problematic workload with the "good" and "bad" kernels (search the list archive for Andrew Morton's instructions on doing it with oprofile, email me privately if you can't find it). > The vmstat man page has little information on this statistic and there seems to be varying > explanations on the web. I was hoping for a decisive explanation (or link) and possibly > advice in toggling this value (or reasons not to). The meaning of these numbers can change drastically from one minor release to the next, and the docs often lag behind the code. I would not focus on tweaking VM knobs, but on describing the problem in enough detail to fix the kernel - it's a bug if the same workload regresses significantly from one release to another. Lee