From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4E09EE85.4040005@domain.hid> Date: Tue, 28 Jun 2011 17:08:53 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4E086122.7060405@domain.hid> <4E09D243.4050706@domain.hid> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Program hangs using "rt_task_sleep" in a particular way List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Adrien LEMAITRE Cc: xenomai@xenomai.org On 06/28/2011 04:02 PM, Adrien LEMAITRE wrote: > Hi, > > Thanks for your answer. > > 2011/6/28 Gilles Chanteperdrix > >> The problem is that the "rt_task_spawn" service causes its caller to >> switch to secondary mode. This means, that the task is no longer real-time. >> > > I wasn't aware of this fact. It could be annoying if we have to create > several RT Tasks... > It's only true for rt_task_spawn or for all Xenomai services ? Which services stay in primary mode, and which services switch to secondary mode is documented in the API documentation: http://www.xenomai.org/documentation/xenomai-2.5/html/api/index.html > > A better practice will to first make several rt_task_create and after > activate them by rt_task_start services? Probably. But if these tasks use 100% cpu and never let linux run, you will have other problems later (the first being that the system will no longer respond to non real-time activities such as the consoles, the graphic system, etc...). > > > >> Normally, root thread priority coupling should allow to avoid that. >> Unfortunately, there is a small hole in this functionality which make it >> not work in some conditions (and fixing this hole would introduce a >> possibility of priority inversion). >> > My advisor (jerome Delatour from ESEO) want to better understand this point, > where could I find explanations on this point ? This is a point discovered recently, see the thread starting here: https://mail.gna.org/public/xenomai-help/2011-03/msg00165.html -- Gilles.