Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755519AbWK1VET (ORCPT ); Tue, 28 Nov 2006 16:04:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755523AbWK1VET (ORCPT ); Tue, 28 Nov 2006 16:04:19 -0500 Received: from smtp3.Stanford.EDU ([171.67.20.26]:24992 "EHLO smtp3.stanford.edu") by vger.kernel.org with ESMTP id S1755519AbWK1VES (ORCPT ); Tue, 28 Nov 2006 16:04:18 -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: <1164746224.15887.40.camel@cmn3.stanford.edu> References: <1164743931.15887.34.camel@cmn3.stanford.edu> <20061128200927.GA26934@elte.hu> <1164746224.15887.40.camel@cmn3.stanford.edu> Content-Type: text/plain Date: Tue, 28 Nov 2006 13:04:14 -0800 Message-Id: <1164747854.15887.48.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: 6233 Lines: 141 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...) -- Fernando preemption latency trace v1.1.5 on 2.6.18-1.0001.3.rt8.fc6.ccrma -------------------------------------------------------------------- latency: 16023 us, #8/8, CPU#0 | (M:rt VP:0, KP:0, SP:1 HP:1 #P:2) ----------------- | task: jackd-3739 (uid:500 nice:0 policy:1 rt_prio:62) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / qjackctl-3740 0Dn.1 1us : __trace_start_sched_wakeup <<...>-3739> (37 0) qjackctl-3740 0Dn.1 3us : try_to_wake_up <<...>-3739> (162 161) qjackctl-3740 0Dn.1 4us : trace_special_sym (ffffffff802668da 0 0) <...>-3739 1D..2 8us : thread_return (199 162) <...>-3739 1D..1 10us+: trace_stop_sched_switched <<...>-3739> (37 1) <...>-3739 1...1 13us : thread_return (thread_return) vim:ft=help preemption latency trace v1.1.5 on 2.6.18-1.0001.3.rt8.fc6.ccrma -------------------------------------------------------------------- latency: 71 us, #14/14, CPU#1 | (M:rt VP:0, KP:0, SP:1 HP:1 #P:2) ----------------- | task: IRQ 18-813 (uid:0 nice:-5 policy:1 rt_prio:70) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / -0 1Dnh3 3us+: __trace_start_sched_wakeup <<...>-813> (29 1) -0 1Dnh3 8us+: try_to_wake_up <<...>-813> (170 20) -0 1Dnh1 22us+: do_IRQ (ffffffff8026f32c 12 0) -0 1Dnh2 25us+: trace_special_sym (ffffffff8028f2ad 0 0) -0 1Dnh3 29us+: __activate_task <<...>-412> (149 1) -0 1Dnh3 33us+: try_to_wake_up <<...>-412> (149 20) -0 1.n.1 40us+: hrtimer_restart_sched_tick (d48a31262d 0) -0 1Dn.2 44us+: enqueue_hrtimer (d48a527afd ffff81000407a950) -0 1Dn.1 52us+: trace_special_sym (ffffffff8024b93e 0 0) <...>-813 1D..2 60us+: thread_return <-0> (20 170) <...>-813 1D..1 64us+: trace_stop_sched_switched <<...>-813> (29 1) <...>-813 1...1 71us : thread_return (thread_return) vim:ft=help preemption latency trace v1.1.5 on 2.6.18-1.0001.3.rt8.fc6.ccrma -------------------------------------------------------------------- latency: 2255 us, #11/11, CPU#0 | (M:rt VP:0, KP:0, SP:1 HP:1 #P:2) ----------------- | task: japa-3782 (uid:500 nice:0 policy:1 rt_prio:61) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / -0 0Dnh2 2236us : hrtimer_interrupt (ec6e49749d ffff81006a68ddc8) -0 0Dnh2 2237us : trace_special_sym (ffffffff8028f2ad 0 0) -0 0Dnh3 2239us : effective_prio <<...>-3619> (-5 -5) -0 0Dnh3 2241us : __activate_task <<...>-3619> (-5 1) -0 0Dnh3 2243us+: try_to_wake_up <<...>-3619> (-5 20) -0 0Dn.1 2246us : trace_special_sym (ffffffff8024b93e 0 0) <...>-3782 0D..2 2250us : thread_return <-0> (20 161) <...>-3782 0D..1 2252us+: trace_stop_sched_switched <<...>-3782> (38 0) <...>-3782 0...1 2255us : thread_return (thread_return) vim:ft=help - 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/