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From: Ingo Molnar <mingo@elte.hu>
To: Roland Dreier <rdreier@cisco.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Early hang with 2.6.21-rc4-rt1
Date: Fri, 30 Mar 2007 11:24:34 +0200	[thread overview]
Message-ID: <20070330092434.GA20903@elte.hu> (raw)
In-Reply-To: <20070330090206.GA14324@elte.hu>


* Ingo Molnar <mingo@elte.hu> 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

      reply	other threads:[~2007-03-30  9:24 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-25  5:03 Early hang with 2.6.21-rc4-rt1 Roland Dreier
2007-03-25  5:29 ` Roland Dreier
2007-03-25  7:29   ` Ingo Molnar
2007-03-25  7:34     ` Ingo Molnar
2007-03-25  8:06       ` Ingo Molnar
2007-03-25 16:27         ` Roland Dreier
2007-03-25  7:31 ` Ingo Molnar
2007-03-25 14:35   ` Roland Dreier
2007-03-25 17:01     ` Roland Dreier
2007-03-27 19:22       ` Ingo Molnar
2007-03-27 19:24       ` Ingo Molnar
2007-03-27 19:42         ` Roland Dreier
2007-03-30  9:02           ` Ingo Molnar
2007-03-30  9:24             ` Ingo Molnar [this message]

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