From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Tue, 11 Sep 2012 09:44:48 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai] Interpreting I-pipe trace
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To: Doug Brunner <dbrunner@ebus.com>
Cc: xenomai@xenomai.org

On 09/11/2012 07:01 AM, Doug Brunner wrote:

> While running my latency testing earlier I saw some rather high 
> worst-case latencies (~70us) compared to average case (~14us), so I ran 
> again with I-pipe tracing enabled. However, I'm not sure what to make of 
> the results.
> 
> My worst case involves an IRQ (common_interrupt appears in the trace 
> with user value 0xFFFFFFC4) and the wiki page talks about being able to 
> translate the user value 0xFFFFFFF4 into IRQ 11 but doesn't elaborate on 
> how this correspondence works. I'm not horribly concerned since it's a 
> delay of 53 us on a rather slow processor (Geode LX800) but it would be 
> nice to know what interrupt is taking so long.
> 
> The trace is attached.


Have you tried booting with "idle=poll" ?

-- 
                                                                Gilles.