Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757888AbWK1XXF (ORCPT ); Tue, 28 Nov 2006 18:23:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757909AbWK1XXF (ORCPT ); Tue, 28 Nov 2006 18:23:05 -0500 Received: from smtp3.Stanford.EDU ([171.67.20.26]:5819 "EHLO smtp3.stanford.edu") by vger.kernel.org with ESMTP id S1757888AbWK1XXC (ORCPT ); Tue, 28 Nov 2006 18:23:02 -0500 Subject: Re: 2.6.19-rc6-rt8: alsa xruns From: Fernando Lopez-Lezcano To: Ingo Molnar Cc: nando@ccrma.Stanford.EDU, "Linux-Kernel," In-Reply-To: <1164749755.15887.54.camel@cmn3.stanford.edu> References: <1164743931.15887.34.camel@cmn3.stanford.edu> <20061128200927.GA26934@elte.hu> <1164746224.15887.40.camel@cmn3.stanford.edu> <1164747854.15887.48.camel@cmn3.stanford.edu> <1164749755.15887.54.camel@cmn3.stanford.edu> Content-Type: text/plain Date: Tue, 28 Nov 2006 15:22:58 -0800 Message-Id: <1164756178.15887.60.camel@cmn3.stanford.edu> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-4.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4020 Lines: 90 On Tue, 2006-11-28 at 13:35 -0800, Fernando Lopez-Lezcano wrote: > On Tue, 2006-11-28 at 13:04 -0800, Fernando Lopez-Lezcano wrote: > > On Tue, 2006-11-28 at 12:37 -0800, Fernando Lopez-Lezcano wrote: > > > On Tue, 2006-11-28 at 21:09 +0100, Ingo Molnar wrote: > > > > * Fernando Lopez-Lezcano wrote: > > > > > > > > > Hi, I'm trying out the latest -rt patch and getting alsa xruns when > > > > > using jackd and jack clients. This is a sample from the output of > > > > > qjackctl / jackd (jack 0.102.25, qjackctl 0.2.21): > > > > > > > > > ( japa-4096 |#0): new 17 us maximum-latency wakeup. > > > > > ( beagled-3412 |#1): new 19 us maximum-latency wakeup. > > > > > ( IRQ 18-1081 |#1): new 26 us maximum-latency wakeup. > > > > > ( snd-4040 |#1): new 1107 us maximum-latency wakeup. > > > > > ( japa-4096 |#0): new 1445 us maximum-latency wakeup. > > > > > ( japa-4096 |#0): new 2110 us maximum-latency wakeup. > > > > > ( qjackctl-4038 |#1): new 2328 us maximum-latency wakeup. > > > > > ( japa-4096 |#0): new 2548 us maximum-latency wakeup. > > > > > ( IRQ 18-1081 |#0): new 10291 us maximum-latency wakeup. > > > > > > > > hm, lets fix this. Could you enable tracing (on the yum rpm) via: > > > > > > > > echo 1 > /proc/sys/kernel/trace_enabled > > > > > > > > does /proc/latency_trace have any meaningful events included for such a > > > > long delay? If not then it would be nice to rebuild the kernel with > > > > CONFIG_LATENCY_TRACING - and in any case my previous suggestion holds > > > > too: booting with maxcpus=1 to reproduce the latencies will give easier > > > > to interpret latency traces. > > > > > > Sorry, it looks like it is an smp issue. Booting with maxcpus=1 reduces > > > the xrun reports significantly (only three so far but very short, in the > > > range of 0.029 to 0.041 ms). The long ones seem to have gone away, so > > > far... > > > > Strange, I rebooted smp and I'm not seeing the very long xruns I was > > seeing before, only short ones as reported above. Here are some traces, > > but nothing that makes sense I think. > > > > I'll turn off the machine and cold boot it...) > > No difference, actually it looks like the regression re-regresses if I > enable the trace... Arghhh. > > Toggling /proc/sys/kernel/trace_enabled makes the long xruns reported by > jack come and go. I still get long xruns with the trace on, but it does not look like it says anything important: ---- preemption latency trace v1.1.5 on 2.6.18-1.0001.3.rt8.fc6.ccrma -------------------------------------------------------------------- latency: 4283 us, #8/8, CPU#0 | (M:rt VP:0, KP:0, SP:1 HP:1 #P:2) ----------------- | task: IRQ 18-819 (uid:0 nice:-5 policy:1 rt_prio:70) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / -0 1Dn.3 4270us+: trace_change_sched_cpu (0 1 0) -0 1Dn.3 4273us : deactivate_task <<...>-819> (170 2) -0 1Dn.3 4275us : __activate_task <<...>-819> (170 1) <...>-819 1D..2 4278us : thread_return <-0> (20 170) <...>-819 1D..1 4280us+: trace_stop_sched_switched <<...>-819> (29 1) <...>-819 1...1 4283us : thread_return (thread_return) vim:ft=help ---- I wonder if it is something that starts happening after some uptime. I'll try rebooting again. -- Fernando - 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/