Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261153AbUKUNaH (ORCPT ); Sun, 21 Nov 2004 08:30:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261158AbUKUNaH (ORCPT ); Sun, 21 Nov 2004 08:30:07 -0500 Received: from mx1.elte.hu ([157.181.1.137]:61063 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S261153AbUKUNaD (ORCPT ); Sun, 21 Nov 2004 08:30:03 -0500 Date: Sun, 21 Nov 2004 15:32:34 +0100 From: Ingo Molnar To: Florian Schmidt Cc: Lee Revell , linux-kernel@vger.kernel.org, Rui Nuno Capela , Mark_H_Johnson@Raytheon.com, "K.R. Foley" , Bill Huey , Adam Heath , Thomas Gleixner , Michal Schmidt , Fernando Pablo Lopez-Lezcano , Karsten Wiese , Gunther Persoons , emann@mrv.com, Shane Shrybman , Amit Shah Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.29-0 Message-ID: <20041121143234.GA23773@elte.hu> References: <20041118123521.GA29091@elte.hu> <20041118164612.GA17040@elte.hu> <1100920963.1424.1.camel@krustophenia.net> <20041120125536.GC8091@elte.hu> <1100971141.6879.18.camel@krustophenia.net> <20041120191403.GA16262@elte.hu> <1100975745.6879.35.camel@krustophenia.net> <20041120201155.6dc43c39@mango.fruits.de> <20041120214035.2deceaeb@mango.fruits.de> <20041121124555.GA7972@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041121124555.GA7972@elte.hu> 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: 850 Lines: 21 * Ingo Molnar wrote: > > So i don't really know how to go about this. I suppose i just run > > PREEMPT kernels instead of PREEMPT_REALTIME. Maybe it's the overhead > > which is killing jackd performance with PREEMPT_REALTIME, but i don't > > believe so (50ms? nah!). > > agreed, no way can 50msec be related to overhead. there's one exception: if the RT workload is _just_ below 100% CPU utilization, then PREEMPT_RT's overhead could push it above 100% and trigger CPU overload, with big delays. What is the maximum CPU usage during the test, while the system is otherwise idle? 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/