Re: Early hang with 2.6.21-rc4-rt1

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxx> wrote:

> > Great, thanks ... I'm not sure which of the 2 patches fixed things, 
> > but I now got the following trace.  I've not really analyzed this, 
> > but it definitely looks like tun_init() is doing something fishy... 
> > ("149776 us maximum-latency"!!)
> 
> best would be to enable FUNCTION_TRACING and to do:
> 
> 	echo 1 > /proc/sys/kernel/trace_enabled
> 	echo 1 > /proc/sys/kernel/mcount_enabled
> 
> this will give you an exact trace of what happened, in 
> /proc/latency_trace.

btw., if you use -rt, it makes sense to disable the UNWIND options in 
the .config - the unwinder causes quite some overhead at places.

	Ingo
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