2005-09-26 19:04:31

by Karsten Wiese

[permalink] [raw]
Subject: Re: jack, PREEMPT_DESKTOP, delayed interrupts?

> # cat /proc/latency_trace
> preemption latency trace v1.1.5 on 2.6.13-0.3.rdtd.rhfc4.ccrmasmp
> --------------------------------------------------------------------
> latency: 10852 us, #70/70, CPU#0 | (M:preempt VP:0, KP:1, SP:1 HP:1
> #P:2)
> -----------------
> | task: qjackctl-4797 (uid:743 nice:0 policy:1 rt_prio:61)
> -----------------
>
> _------=> CPU#
> / _-----=> irqs-off
> | / _----=> need-resched
> || / _---=> hardirq/softirq
> ||| / _--=> preempt-depth
> |||| /
> ||||| delay
> cmd pid ||||| time | caller
> \ / ||||| \ | /
> <...>-4593 1Dnh3 0us : MacPrivateStat (SkPnmiGetStruct)
> <...>-4593 1Dnh3 0us : MacPrivateStat (SkPnmiGetStruct)
<snip>
> <...>-4593 1Dnh3 18us : SkGmMacStatistic (GetPhysStatVal)
> <...>-4593 1Dnh3 20us : GetStatVal (MacPrivateStat)
> <...>-4593 1Dnh3 20us : GetPhysStatVal (GetStatVal)
> <...>-4593 1Dnh3 20us+: SkGmMacStatistic (GetPhysStatVal)
> <...>-4593 1Dnh3 22us : GetStatVal (MacPrivateStat)
> <...>-4593 1Dnh3 22us : GetPhysStatVal (GetStatVal)
> <...>-4593 1Dnh3 22us+: SkGmMacStatistic (GetPhysStatVal)
> <...>-4593 1Dnh3 24us!: MacPrivateStat (SkPnmiGetStruct)
> softirq--8 0Dnh4 9901us : trace_change_sched_cpu (1 0 0)

Maybe your ethernet device is getting in the way.
Do you also get jack dropouts with ethernet chip disabled,
it's Module unloaded?

Karsten


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2005-09-28 09:38:00

by Ingo Molnar

[permalink] [raw]
Subject: Re: jack, PREEMPT_DESKTOP, delayed interrupts?


* Karsten Wiese <[email protected]> wrote:

> > latency: 10852 us, #70/70, CPU#0 | (M:preempt VP:0, KP:1, SP:1 HP:1

> > softirq--8 0Dnh4 9901us : trace_change_sched_cpu (1 0 0)
>
> Maybe your ethernet device is getting in the way.
> Do you also get jack dropouts with ethernet chip disabled,
> it's Module unloaded?

also, the M:preempt suggests that it's not a PREEMPT_RT kernel but a
PREEMPT_DESKTOP kernel. Do the dropouts happen even with a PREEMPT_RT
kernel?

Ingo

2005-09-28 16:29:21

by Fernando Lopez-Lezcano

[permalink] [raw]
Subject: Re: jack, PREEMPT_DESKTOP, delayed interrupts?

On Wed, 2005-09-28 at 11:38 +0200, Ingo Molnar wrote:
> * Karsten Wiese <[email protected]> wrote:
>
> > > latency: 10852 us, #70/70, CPU#0 | (M:preempt VP:0, KP:1, SP:1 HP:1
>
> > > softirq--8 0Dnh4 9901us : trace_change_sched_cpu (1 0 0)
> >
> > Maybe your ethernet device is getting in the way.
> > Do you also get jack dropouts with ethernet chip disabled,
> > it's Module unloaded?
>
> also, the M:preempt suggests that it's not a PREEMPT_RT kernel but a
> PREEMPT_DESKTOP kernel. Do the dropouts happen even with a PREEMPT_RT
> kernel?

Last time I tried a PREEMPT_RT (not that long ago) I was not able to
boot into it, it was failing very very early in the boot sequence. I
could try again if it would be valuable.

-- Fernando