BOUNCE rtl@rtlinux.org: Approval required: Non-member submissionfrom [=?iso-8859-1?Q?S=E9bastien?= GAUME<sgaume@b2i-toulous (fwd)

[Der Herr Hofrat <der.herr@hofr.at>]

>From owner-rtl Wed May  9 03:48:31 2001
Received: from mail.b2i-toulouse.com (host.97.67.23.62.rev.coltfrance.com [62.23.67.97])
	by hq.fsmlabs.com (8.11.2/8.11.2) with ESMTP id f499mUJ20384
	for <rtl@fsmlabs.com>; Wed, 9 May 2001 03:48:30 -0600
Received: from b2i-toulouse.com (wilson.b2i-toulouse.com [192.168.0.25] (may be forged))
	by mail.b2i-toulouse.com (8.11.0/8.11.0) with ESMTP id f498eLd00973
	for <rtl@fsmlabs.com>; Wed, 9 May 2001 10:40:22 +0200
Message-ID: <3AF911DE.EC4E064E@b2i-toulouse.com>
Date: Wed, 09 May 2001 11:46:06 +0200
From: =?iso-8859-1?Q?S=E9bastien?= GAUME <sgaume@b2i-toulouse.com>
Organization: b2i-toulouse
X-Mailer: Mozilla 4.75 [fr] (WinNT; U)
X-Accept-Language: fr
MIME-Version: 1.0
To: rtl@fsmlabs.com
Subject: Nanosleep and priority
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Hello !

I've come across surprising results while using the nanosleep function
in my realtime tasks. I wrote a program in which two tasks are created.
Both are periodic (running under the oneshot mode, period = 5 ms), are
supposed to start at the same time and should last 2 ms. One has a
greater priority level then the other. And I'm aiming to check if the
realtime scheduling works well.

What  really surprises me is that the task with the lower priority level
always starts about 20 us after the first task ! At that moment, this
task is not supposed being able to wake up and to start...

I  feel the impression that the realtime tasks behave as if there is no
realtime scheduling, although the fifo realtime scheduling should be on
and work.

So, I you have any idea of what the problem could be,...

Thank you

Sebastien