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Date: Thu, 01 Nov 2007 11:56:56 +0100
From: Jan Kiszka <jan.kiszka@domain.hid>
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Subject: Re: [Xenomai-help] task rate control with alarm and semaphore
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To: MEYLAN Jean-philippe <Jean-philippe.Meylan@domain.hid>
Cc: xenomai@xenomai.org

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MEYLAN Jean-philippe wrote:
> Hello,
>=20
> I'm working on the creation of a Xenomai target for Mathwork's
> Real Time Workshop. In order to achieve this, I would like to=20
> control the execution rate of a task with a semaphore periodically
> released by an alarm handler. The tasks does nothing else but waiting
> (in a loop) on the semaphore. If the task can immediately take=20
> the sempahore, it means that the rate is too fast for it because
> the semaphore has been released before the end of its current iteration=
=2E

Some more efficient way is to let the thread monitor its execution time
and derive the next wakeup date from it. Think of:

next_wakeup =3D now();
do_forever
	next_wakeup +=3D period;
	do_some_rt_job();
	if next_wakeup >=3D now() then
		handle_overload()
	sleep_until(next_wakeup)

Jan


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