Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750807AbWERIkB (ORCPT ); Thu, 18 May 2006 04:40:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751118AbWERIkA (ORCPT ); Thu, 18 May 2006 04:40:00 -0400 Received: from ecfrec.frec.bull.fr ([129.183.4.8]:51334 "EHLO ecfrec.frec.bull.fr") by vger.kernel.org with ESMTP id S1751037AbWERIj7 convert rfc822-to-8bit (ORCPT ); Thu, 18 May 2006 04:39:59 -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: <200605151830.23544.dvhltc@us.ibm.com> References: <200605121924.53917.dvhltc@us.ibm.com> <200605131601.31880.dvhltc@us.ibm.com> <20060515081341.GB24523@elte.hu> <200605151830.23544.dvhltc@us.ibm.com> Date: Thu, 18 May 2006 10:44:22 +0200 Message-Id: <1147941862.4996.15.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 10:43:06, Serialize by Router on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 18/05/2006 10:43:08, Serialize complete at 18/05/2006 10:43:08 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: 900 Lines: 25 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. 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/