From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: Doug Brunner <dbrunner@ebus.com>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai] Interpreting I-pipe trace
Date: Tue, 11 Sep 2012 23:19:34 +0200 [thread overview]
Message-ID: <504FAAE6.5010701@xenomai.org> (raw)
In-Reply-To: <504F8F55.9080006@xenomai.org>
On 09/11/2012 09:21 PM, Gilles Chanteperdrix wrote:
> 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.
>
>
> You may also want to apply the following patch for SMI on Geode LX, and
> enable CONFIG_XENO_HW_SMI_WORKAROUND. You can remove the '#if 0', if you
> do not use PCI.
You have to pass cs5536.msr=1 to avoid using PCI registers access (which
use SMIs) in the IDE driver.
--
Gilles.
next prev parent reply other threads:[~2012-09-11 21:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-11 5:01 [Xenomai] Interpreting I-pipe trace Doug Brunner
2012-09-11 7:44 ` Gilles Chanteperdrix
2012-09-11 7:48 ` Philippe Gerum
2012-09-11 19:21 ` Gilles Chanteperdrix
2012-09-11 21:19 ` Gilles Chanteperdrix [this message]
2012-09-12 6:53 ` Gilles Chanteperdrix
[not found] ` <505667A8.9040409@ebus.com>
2012-09-17 7:01 ` Gilles Chanteperdrix
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