Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751324AbWERJxu (ORCPT ); Thu, 18 May 2006 05:53:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751326AbWERJxu (ORCPT ); Thu, 18 May 2006 05:53:50 -0400 Received: from ecfrec.frec.bull.fr ([129.183.4.8]:5291 "EHLO ecfrec.frec.bull.fr") by vger.kernel.org with ESMTP id S1751324AbWERJxt convert rfc822-to-8bit (ORCPT ); Thu, 18 May 2006 05:53:49 -0400 Subject: Re: rt20 scheduling latency testcase and failure data From: =?ISO-8859-1?Q?S=E9bastien_Dugu=E9?= To: Darren Hart Cc: Ingo Molnar , Lee Revell , lkml , Thomas Gleixner , Mike Galbraith , Steven Rostedt , Florian Schmidt In-Reply-To: <200605180238.33044.dvhltc@us.ibm.com> References: <200605121924.53917.dvhltc@us.ibm.com> <20060518084722.GA3343@elte.hu> <1147942687.4996.28.camel@frecb000686> <200605180238.33044.dvhltc@us.ibm.com> Date: Thu, 18 May 2006 11:58:10 +0200 Message-Id: <1147946290.4996.33.camel@frecb000686> Mime-Version: 1.0 X-Mailer: Evolution 2.4.2.1 X-MIMETrack: Itemize by SMTP Server on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 18/05/2006 11:56:55, Serialize by Router on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 18/05/2006 11:56:58, Serialize complete at 18/05/2006 11:56:58 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1793 Lines: 43 On Thu, 2006-05-18 at 02:38 -0700, Darren Hart wrote: > On Thursday 18 May 2006 01:58, S?bastien Dugu? wrote: > > On Thu, 2006-05-18 at 10:47 +0200, Ingo Molnar wrote: > > > * S?bastien Dugu? wrote: > > > > Darren, > > > > > > > > On Mon, 2006-05-15 at 18:30 -0700, Darren Hart wrote: > > > > > Following Ingo's example I have included the modified test case > > > > > (please see the original mail for librt.h) that starts the trace > > > > > before each sleep and disables it after we wake up. If we have > > > > > missed a period, we print the trace. > > > > > > > > Your test program fails (at least on my box) as the overhead of > > > > starting and stopping the trace in the 5 ms period is just too high. > > > > > > > > By moving the latency_trace_start() at the start of the thread > > > > function and latency_trace_stop() at the end, everything runs fine. I > > > > did not have any period missed even under heavy load. > > > > > > could you send us the fixed testcase? > > > > No problem, see attachment. > > I found several similar problems in my original test case, please see my > earlier mail from today where I included a completely rewritten test case > with buffered output and new periodic logic. > > The case attached here seems to try to print the trace without first stopping > it. I don't think that will result in the desired output. My new test case > addresses that issue as well. > > I'd appreciate any feedback, thanks. > Just saw your post, testing now... S?bastien. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/