Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262376AbUJ0Kde (ORCPT ); Wed, 27 Oct 2004 06:33:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262385AbUJ0Kau (ORCPT ); Wed, 27 Oct 2004 06:30:50 -0400 Received: from mx2.elte.hu ([157.181.151.9]:59805 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S262362AbUJ0K2W (ORCPT ); Wed, 27 Oct 2004 06:28:22 -0400 Date: Wed, 27 Oct 2004 12:29:21 +0200 From: Ingo Molnar To: Florian Schmidt Cc: "K.R. Foley" , linux-kernel@vger.kernel.org, Lee Revell , Rui Nuno Capela , Mark_H_Johnson@Raytheon.com, Bill Huey , Adam Heath , Thomas Gleixner , Michal Schmidt , Fernando Pablo Lopez-Lezcano , Alexander Batyrshin Subject: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0 Message-ID: <20041027102921.GA28764@elte.hu> References: <417D4B5E.4010509@cybsft.com> <20041025203807.GB27865@elte.hu> <417E2CB7.4090608@cybsft.com> <20041027002455.GC31852@elte.hu> <417F16BB.3030300@cybsft.com> <20041027082831.GA15192@elte.hu> <20041027084401.GA15989@elte.hu> <20041027085221.GA16742@elte.hu> <20041027090620.GA17621@elte.hu> <20041027123329.14570992@mango.fruits.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041027123329.14570992@mango.fruits.de> 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: 2096 Lines: 50 * Florian Schmidt wrote: > jackd runs with a period size of 128 frames (48000hz samplerate) and with > SCHED_FIFO with prios from 60 to 70 (ps output is somewhat broken): > > mango:~# ps -cmL `pidof jackd` > PID LWP CLS PRI TTY STAT TIME COMMAND > 1286 - - - ? - 0:28 /usr/bin/jackd -R -P60 -t20000 -dalsa - > - 1286 TS 20 - SLsl 0:00 - > - 1287 TS 23 - SLsl 0:00 - > - 1288 FF 110 - SLsl 0:00 - > - 1289 FF 100 - SLsl 0:27 - > > ~$ chrt -p 1286 > pid 1286's current scheduling policy: SCHED_OTHER > pid 1286's current scheduling priority: 0 > ~$ chrt -p 1287 > pid 1287's current scheduling policy: SCHED_OTHER > pid 1287's current scheduling priority: 0 just curious, are these two important to the latency path of jackd, or are they lowprio things and are thus at SCHED_OTHER intentionally? > ~$ chrt -p 1288 > pid 1288's current scheduling policy: SCHED_FIFO > pid 1288's current scheduling priority: 70 > ~$ chrt -p 1289 > pid 1289's current scheduling policy: SCHED_FIFO > pid 1289's current scheduling priority: 60 > > Anyways i get xruns like crazy under load (like 200 in 10 minutes). It > seems the scheduling class and high priority don't matter really as > wiggling windows around on the screen or doing a "find /" can easily > provoke xruns. yeah, i'm hunting a quite similar bug: i can see 'realfeel' latencies generated by simple window scrolling. It is most likely a logic bug somewhere - a missing reschedule check, irqs left disabled accidentally, or something like that. Since some other workloads dont trigger it i dont think i broke RT scheduling by itself - it is most likely some non-core code somewhere missing a resched. Which doesnt make it less of a problem, but it makes it harder to find :-| 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/