Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262069AbUK3NVL (ORCPT ); Tue, 30 Nov 2004 08:21:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262067AbUK3NVK (ORCPT ); Tue, 30 Nov 2004 08:21:10 -0500 Received: from mx2.elte.hu ([157.181.151.9]:57773 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S262070AbUK3NUx (ORCPT ); Tue, 30 Nov 2004 08:20:53 -0500 Date: Tue, 30 Nov 2004 14:19:56 +0100 From: Ingo Molnar To: Rui Nuno Capela Cc: linux-kernel@vger.kernel.org, Lee Revell , mark_h_johnson@raytheon.com, "K.R. Foley" , Bill Huey , Adam Heath , Florian Schmidt , Thomas Gleixner , Michal Schmidt , Fernando Pablo Lopez-Lezcano , Karsten Wiese , Gunther Persoons , emann@mrv.com, Shane Shrybman , Amit Shah , Esben Nielsen Subject: Re: Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.31-7 Message-ID: <20041130131956.GA23451@elte.hu> References: <36536.195.245.190.93.1101471176.squirrel@195.245.190.93> <20041129111634.GB10123@elte.hu> <41358.195.245.190.93.1101734020.squirrel@195.245.190.93> <20041129143316.GA3746@elte.hu> <20041129152344.GA9938@elte.hu> <48590.195.245.190.94.1101810584.squirrel@195.245.190.94> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48590.195.245.190.94.1101810584.squirrel@195.245.190.94> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1286 Lines: 39 * Rui Nuno Capela wrote: > xruntrace1-2.6.10-rc2-mm3-RT-V0.7.31-13-*.trc.gz > - the captured traces, as dumped with xruntrace1_watch.sh script. > Each trace shows only the first XRUN occurrence on a distinct jackd > session. Every other trace were triggered and captured after > restarting jackd. interesting - the trace shows only a latency of 20-40 usecs. Perhaps the tracing should be done over two periods? Could you try to hack alsa_driver.c to do the gettimeofday(1,1) call for only every second case. Something like this ought to be enough: { static count = 0; if (!(count++ & 1)) gettimeofday(0,1); } (only one thread accesses this particular variable so there are no threading issues.) with this variant there's a 50% chance that we get the trace of the last 2 poll() instances. (and there's a 50% chance that we get only 1 period covered.) in any case, the scripts & approach seems to be almost there, i hope we only need the above change to see the true source of the xruns. Ingo - 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/