From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43592FFE.6060003@domain.hid> Date: Fri, 21 Oct 2005 20:14:22 +0200 From: Philippe Gerum MIME-Version: 1.0 Subject: Re: [Xenomai-core] EDF or RM scheduler for Xenomai References: <1436.10.2.100.4.1129898928.squirrel@domain.hid> In-Reply-To: <1436.10.2.100.4.1129898928.squirrel@domain.hid> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Germain Olivier Cc: xenomai@xenomai.org Germain Olivier wrote: > At the beginning of October I've posted on the RTAI mailing list a > question about the development of additional scheduler for RTAI/Fusion. > > About the pluggable scheduler infrastructure, can you give more details on > what you expect ? > An implementation in the nucleus that make scheduling policies provided as software plugins, so that we don't end up with braindamage exception cases in nucleus/pod.c in order to support them. As of now, nucleus/pod.c implements the fixed priority FIFO policy in a hard-wired manner: to have other policies integrated into the core, we need to think of a lightweight generic infrastructure for hosting those plugins that would replace the hard-coded, FIFO-based, scheduling decisions. > Also I'm searching in which files the priority inheritance mechanism code > is implemented. > nucleus/sync.c. > Thanks > > Germain > > >>100% agreed. The key issue is having the pluggable scheduler >>infrastructure >>which fusion currently lacks. After that, other scheduling policies than >>fixed-priority FIFO could be mapped cleanly and easily on top of it. > > > >>Jan Kiszka wrote: >> >>>Germain wrote: >>> >>> >>>>According to refactoring.txt from Fusion doc directory, Rate Monotonic >>>>and >>>>EDF are not supported in Fusion. >>>>I'm in my last year of CS engineering school with a major in Emmbedded >>>>Systems. One of the subject of my final year project is to write a >>>>scheduler (Rate Monotonic, Earliest Deadline First or Least Laxity >>>>First). >>>>So I want to know what kind of knowledges is required to put the hand in >>>>RTAI and develop a such thing. We are two and we have to finish for >>>>early >>>>february. We have skills in C, real time theory and developpment (with >>>>Java), and system programming. >>>> >>> >>> >>>This would best be answered by the nucleus maintainer, who seems to be >>>offline ATM. >> >> Philippe already acknowledged the usefulness of a more >> >>>flexible scheduling subsystem which, e.g., allows to select a different >>>policy during compile time or even later. What is certainly required for >>>this is a clean framework that keeps the compatibility with the upper >>>(skins) and lower layers (hal) - as far as possible. >>> >>>Again, this is something to discuss best with Philippe directly. I guess >>>he will jump into this thread when time permits. In my eyes, your work >>>would be very welcome. >>> >> >>100% agreed. The key issue is having the pluggable scheduler >>infrastructure >>which fusion currently lacks. After that, other scheduling policies than >>fixed-priority FIFO could be mapped cleanly and easily on top of it. >> >>Hint: scheduling issues are all sorted out inside nucleus/pod.c; >>nucleus/synch.c >>should be also studied in order to find out the relashionships that exist >>between base synchronization object management and scheduling deci > > > _______________________________________________ > Xenomai-core mailing list > Xenomai-core@domain.hid > https://mail.gna.org/listinfo/xenomai-core > -- Philippe.