From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: "Krzysztof Błaszkowski" <kb@domain.hid>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai-core] rt timer jitter
Date: Sat, 21 Aug 2010 11:08:09 +0200 [thread overview]
Message-ID: <4C6F9779.8000206@domain.hid> (raw)
In-Reply-To: <1282319702.5255.405.camel@domain.hid>
Krzysztof Błaszkowski wrote:
> Do you have any idea about reducing rt timer jitter ?
> I experience annoyingly big jitter in a thread which is supposed to run
> at 400us (i reckon this is nothing extra demanding from atom @1.6G)
> thread_task:2651 peak rt jitter -18470[ns], tsc delta 697450
>
>
> I must say it is 4 - 5 times worse if compared to rtai 3.7 / 2.6.27.19
> UP.
>
> I use now xenomai 2.5.4 with adeos 2.2-06 patch for same 2.6.27 kernel
> to make these comparisons more reliable.
>
>
> Can i do something with this ?
Ok. I had read that you had 400us jitter, this would have been pathological.
But 10us or 20us jitter on an ATOM is not.
The jitter on an idle system is not really significant, only the worst
case under several hours of heavy load is really significant.
--
Gilles.
prev parent reply other threads:[~2010-08-21 9:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-20 15:55 [Xenomai-core] rt timer jitter Krzysztof Błaszkowski
2010-08-20 16:00 ` Gilles Chanteperdrix
2010-08-20 16:01 ` Gilles Chanteperdrix
2010-08-20 16:14 ` Krzysztof Błaszkowski
2010-08-20 16:32 ` Philippe Gerum
2010-08-20 16:06 ` Philippe Gerum
2010-08-20 16:20 ` Krzysztof Błaszkowski
2010-08-20 16:31 ` Philippe Gerum
2010-08-21 9:08 ` Gilles Chanteperdrix [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4C6F9779.8000206@domain.hid \
--to=gilles.chanteperdrix@xenomai.org \
--cc=kb@domain.hid \
--cc=xenomai@xenomai.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.