From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: rpm@xenomai.org
Cc: Xenomai-help@domain.hid
Subject: Re: [Xenomai-help] Latency calculation and test
Date: Thu, 03 May 2007 18:44:36 +0200 [thread overview]
Message-ID: <463A1174.60105@domain.hid> (raw)
In-Reply-To: <1178208712.29605.109.camel@domain.hid>
Philippe Gerum wrote:
> On Thu, 2007-05-03 at 17:07 +0200, Gilles Chanteperdrix wrote:
>
> That was not my point. My point was: don't stuff huge semi-random values
> into /proc/xenomai/latency to work around terrible jittery especially
> when porting Xenomai over new platforms, because this is _likely_ the
> sign of something going wrong elsewhere.
>
> E.g. An oldish 90Mhz classic pentium exhibits ~25 us core latency
> figures with Xenomai; some ARM hw may require more because of
> unfortunate memory sub-systems, but in any case, you have to
> _understand_ (e.g. using the tracer) why it is so, first.
I agree. I still have to see for myself why these damned ARMs have such
high latencies.
>>We should add a page on the wiki about the latency calibration.
>>
>
>
> We should also provide an external tool for determining the most
> appropriate latency for a given workload / configuration.
The latency tool already does a great deal of this job.
--
Gilles Chanteperdrix
next prev parent reply other threads:[~2007-05-03 16:44 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-03 12:35 [Xenomai-help] Latency calculation and test Johan Borkhuis
2007-05-03 13:29 ` Philippe Gerum
2007-05-03 14:07 ` Gilles Chanteperdrix
2007-05-04 7:58 ` Johan Borkhuis
2007-05-04 9:17 ` Gilles Chanteperdrix
2007-05-04 12:32 ` Philippe Gerum
2007-05-04 12:43 ` Jan Kiszka
2007-05-07 6:51 ` Johan Borkhuis
2007-05-07 8:29 ` Johan Borkhuis
2007-05-07 8:58 ` Jan Kiszka
2007-05-07 11:58 ` Johan Borkhuis
2007-05-07 12:11 ` Jan Kiszka
2007-05-07 12:37 ` Johan Borkhuis
2007-05-07 13:52 ` Jan Kiszka
2007-05-08 6:57 ` Johan Borkhuis
2007-05-09 7:17 ` Jan Kiszka
2007-05-09 7:49 ` Philippe Gerum
2007-05-07 12:30 ` Gilles Chanteperdrix
2007-05-07 13:21 ` Jan Kiszka
2007-05-03 13:42 ` Daniel Schnell
2007-05-03 14:54 ` Philippe Gerum
2007-05-03 15:07 ` Gilles Chanteperdrix
2007-05-03 15:43 ` Daniel Schnell
2007-05-03 18:42 ` Gilles Chanteperdrix
2007-05-03 18:47 ` Jan Kiszka
2007-05-04 6:51 ` Daniel Schnell
2007-05-03 16:11 ` Philippe Gerum
2007-05-03 16:44 ` Gilles Chanteperdrix [this message]
2007-05-03 17:17 ` Philippe Gerum
2007-05-03 17:26 ` Jan Kiszka
2007-05-04 12:46 ` Bill Gatliff
2007-05-04 8:04 ` Johan Borkhuis
2007-05-03 14:38 ` Gilles Chanteperdrix
2007-05-03 19:23 ` Gilles Chanteperdrix
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