From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <497883B1.6030005@domain.hid> Date: Thu, 22 Jan 2009 14:33:21 +0000 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <5D63919D95F87E4D9D34FF7748CE2C2A01776D54@domain.hid> In-Reply-To: <5D63919D95F87E4D9D34FF7748CE2C2A01776D54@domain.hid> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [Xenomai-help] How to use Xenomai libraries with "normal" (non Xenomai) linux processes ? List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: roderik.wildenburg@domain.hid Cc: xenomai@xenomai.org roderik.wildenburg@domain.hid wrote: >>> Please correct me if I am wrong: In your replacement=20 >>> pthread_getschedparam would read scheduling parameters which >>> should have been set with sched_setscheduler before(!) your >> replacement gets >>> active. Is this possible at all ? Wouldn=B4t I have to call=20 >>> sched_setscheduler (in "sysup") before I fork? And if calling >>> after the fork it realy would be racy. So this isn=B4t a very >>> feasible solution, isn=B4t it? Changing the scheduling paramters of >>> a running Xenoami task probably isn=B4t possible (probably there is >>> nothing to recognize the change ?)? >> You are just repeating what I said. So, I have not much more to >> say. >>=20 >=20 > Yes, but with my own words, so you can tell me whether I understood > you or not ;-). Yes you understood. >=20 >>> Linux and Linux is the lowest priority task in Xenomai. So, as >>> soon as a task is in secondary mode every(!) Xenomai primary mode >>> task would be scheduled in front of a secondary mode task, I >>> thought. So, if your statement is right, I can=B4t see the >>> difference between primary and secondary mode any more as a >>> higher prioritized task obviously allways(!?) runs in front of a >>> lower prioritized one independend whether it runs in primary or >>> secondary mode? Is there some documenation I could read for >>> better understanding ? Is this behaviour connected to the Xenomai >>> "priority coupling" option? >> Yes, it is what priority coupling means. But it really is the most >> sane behaviour: you choose a priority and both Linux and Xenomai >> schedulers cooperate to enfore this priority. >=20 > How are Linux tasks treated which are not linked with any Xenomay > library, but whose scheduling is set to SCHED_FIFO and whose priority > is set to some value higher than a Xenomai tasks (with > sched_setscheduler). When do they run ? They can prevent a Xenomai task running in secondary mode from running, but not a Xenomai task running in primary mode. --=20 Gilles.