Dear Gurus, I have 2 fundamental questions and I appologize in advance to burden you with more answering jobs stealing your precious development time, but at least the first question is crutial to our project.
1.) Essentially the question deals with the problem, how long a Xenomai task in secondary mode can be delayed by normal Linux tasks. In detail : we plan to to have a lot of "near realtime" ethernet communication from within Xenomai using the normal Linux network stack (calling the normal socket API). The question now is, how our network communication is influenced by other Linux tasks performing also network communication, let´s say an FTP transfer ? (I have heard about RT-Net, but as far as I understand it needs its own realtime domain and therefore a gateway to communicate with the outside world. We want to avoid this.) I have created a scheduling scenario and I would ask you to have a look on it and to tell me whether it is correct or not. Thank you ! An corresponding question about this scheduling is : are there differences between a 2.4 and 2.6 Linux kernel ? (for our PowerPC plattform we intend to use the 2.4 kernel for performance reasons) Scheduling scenario : (I hope formating is not destroyed by email transfer) Time moves downwards v-Xenomai v-Linux kernel v-Linux processes l1 Linux task1 running s1 < l1 Linux task1 makes systemcall s1 Linux task1 systemcall processed ------------- Linux scheduling l2 Linux task2 starts to run s2 < l2 Linux task2 makes systemcall s2 Linux task2 systemcall processed +++++++++++++ Xenomai scheduling x3 Xenomai task3 starts to run => primary mode x3 > s3 Xenomai task3 makes systemcall => secondary mode s3 Xenomai task3 systemcall processed ------------- Linux scheduling => Xenomai task preemted s1 Linux task1 systemcall processed s1 > l1 Linux task1 systemcall ready => Linux task1 continues l1 Linux task1 continues ------------- Linux scheduling s2 Linux task2 systemcall processed s2 > l2 Linux task2 systemcall ready => Linux task2 continues l2 Linux task2 continues ------------- Linux scheduling => Xenomai Task3 systemcall continued s3 Xenomai Task3 systemcall continued x3 < s3 Xenomai Task3 systemcall ready => Xenomai Task contiunes x3 but has been delayed by normal Linux tasks 2.) This question is not so crucial, but nevertheless interesting : Who are the people behind Xenomai (I did not find anything about this on the Xenomai webpage), what is their background (University, Company)and who impels /sponsors the Xenomai development (University, Company, Community)? I think I "identified" at least 2 core developers : Philippe Gerum and Gilles Chanteperdrix, but I don´t know very much more. The background for this question is, to get a feeling, how future-proof the xenomai development is. As far as I can see open source projects often die or stall when the initiators decide that "growing flowers" is a much more pleasant job ;-). Thank you for taking time to answer these questions, which are interesting to others too, I think !? Best Regards Roderik _______________________________________________ Xenomai-core mailing list Xenomaifirstname.lastname@example.org https://mail.gna.org/listinfo/xenomai-core