From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754303AbXD0SWh (ORCPT ); Fri, 27 Apr 2007 14:22:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756984AbXD0SWh (ORCPT ); Fri, 27 Apr 2007 14:22:37 -0400 Received: from mail.tmr.com ([64.65.253.246]:48597 "EHLO gaimboi.tmr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754303AbXD0SWg (ORCPT ); Fri, 27 Apr 2007 14:22:36 -0400 Message-ID: <46323F6F.6070903@tmr.com> Date: Fri, 27 Apr 2007 14:22:39 -0400 From: Bill Davidsen Organization: TMR Associates Inc, Schenectady NY User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061105 SeaMonkey/1.0.6 MIME-Version: 1.0 To: Con Kolivas CC: Ingo Molnar , Ed Tomlinson , Linux Kernel M/L Subject: Re: [REPORT] First "glitch1" results, 2.6.21-rc7-git6-CFSv5 + SD 0.46 References: <462D2BDD.4040406@tmr.com> <20070424065709.GB19802@elte.hu> <46312116.1030506@tmr.com> <200704270856.17210.kernel@kolivas.org> In-Reply-To: <200704270856.17210.kernel@kolivas.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Con Kolivas wrote: > On Friday 27 April 2007 08:00, Bill Davidsen wrote: > >> Ingo Molnar wrote: >> >>> * Ed Tomlinson wrote: >>> >>>>> SD 0.46 1-2 FPS >>>>> cfs v5 nice -19 219-233 FPS >>>>> cfs v5 nice 0 1000-1996 >>>>> >>>> cfs v5 nice -10 60-65 FPS >>>> >>> the problem is, the glxgears portion of this test is an _inverse_ >>> testcase. >>> >>> The reason? glxgears on true 3D hardware will _not_ use X, it will >>> directly use the 3D driver of the kernel. So by renicing X to -19 you >>> give the xterms more chance to show stuff - the performance of the >>> glxgears will 'degrade' - but that is what you asked for: glxgears is >>> 'just another CPU hog' that competes with X, it's not a "true" X client. >>> >>> if you are after glxgears performance in this test then you'll get the >>> best performance out of this by renicing X to +19 or even SCHED_BATCH. >>> >> Several points on this... >> >> First, I don't think this is accelerated in the way you mean, the >> machine is a test server, with motherboard video using the 945G video >> driver. Given the limitations of the support in that setup, I don't >> think it qualified as "true 3D hardware," although I guess I could try >> using the vesafb version as a test. >> >> The 2nd thing I note is that on FC6 this scheduler seems to confuse >> 'top' to some degree, since the glxgears is shown as taking 51% of the >> CPU (one core), while the state breakdown shows about 73% in idle, >> waitio, and int. image attached. >> > > top by itself certainly cannot be trusted to give true representation of the > cpu usage I'm afraid. It's not as convoluted as, say, trying to track memory > usage of an application, but top's resolution being tied to HZ accounting > makes it not reliable in that regard. > >> After I upgrade the kernel and cfs to the absolute latest I'll repeat >> this, as well as test with vesafb, and my planned run under heavy load. >> > > I have a problem with your test case Bill. Its behaviour would depend on how > gpu bound vs cpu bound vs accelerated vs non-accelerated your graphics card > is. I get completely different results to those of the other testers given > the different hardware configuration and I don't think my results are > valuable. My problem with this testcase is - What would you define > as "perfect" behaviour for your test case? It seems far too arbitrary. > > It was more intended to give an immediate feedback on gross behavior. On some old schedulers (2.4.x) it visibly ran one xterm after the other, while on 2.6.2[01] that behavior is gone and all schedulers give equal time as seen by the eye. Looking at the behavior with line and jump scroll, under load or not, X nice or nasty, allows a quick check on where the bad cases are if any exist. I intended it as a quick way to determine really, visibly, bad scheduling, not a a test for quantifying performance. The fact that fps varies by almost an order of magnitude with some earlier versions of the schedulers is certainly a red flag to me that there's a corner case, and something I care more about than glxgears will be inconsistent as well. Hopefully in that context, as a relatively quick way to try nice and load values, it's a useful tool. -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979