From mboxrd@z Thu Jan 1 00:00:00 1970 References: <777d8ed5-7f6a-4e56-7f65-7677f089527e@cs.ru.nl> <916ef19a754d4e42b0eaefa8a1a26060@EXPRD08.hosting.ru.nl> <5faff965-afc6-f70a-8d10-8f55c570fbf6@cs.ru.nl> From: Philippe Gerum Subject: Re: rt_task_set_priority does not increase priority of other task In-reply-to: <5faff965-afc6-f70a-8d10-8f55c570fbf6@cs.ru.nl> Date: Thu, 17 Sep 2020 15:26:08 +0200 Message-ID: <87wo0s7cwf.fsf@xenomai.org> MIME-Version: 1.0 Content-Type: text/plain List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Harco Kuppens Cc: Jan Kiszka , xenomai@xenomai.org Harco Kuppens via Xenomai writes: > On 17/09/2020 13:51, Jan Kiszka wrote: >> On 16.09.20 20:12, Harco Kuppens via Xenomai wrote: >>> Hi, >>> >>> I found a problem with rt_task_set_priority function which does not >>> increase priority of another task. >>> However it works fine if you increase the priority of another task. >>> >>> Below is an en example program and its output, and we run this program >>> on xenomai 3.08. >>> The problem appears if we run the program on our xenomai image for the >>> raspberry pi 3, >>> and is also appears in our virtual box image. >>> Both images can be found at : >>> >>> * http://www.cs.ru.nl/lab/xenomai/raspberrypi.html >>> * http://www.cs.ru.nl/lab/xenomai/virtualbox.html >>> >>> The easiest way is to run the virtualbox image. >>> >>> The final question I have: is there an wrong usage of xenomai API in the >>> example program, >>> or is this a bug in xenomai? >>> >> Something is inconsistent here. Did you also check via >> /proc/xenomai/sched/threads if that view is consistent with the result >> of inquire? > yes, and they also said the priority was not increased. > You can repeat the experiment in the virtualbox image. > Note: we use virtualbox so that students can do some exercise at > home. The exerecises on hardware they must do on raspberry pi 3 in the > lab. > Normally a rt os on virtualbox would make no sense. >> I vaguely recall issues of the latter but I also do not >> recall any fix to 3.1, not to speak of anything that was not backported. > >> BTW, tried 3.1 as well? > no, because I don't have it installed. Could someone who has it > running try this example on it, and check whether this problem also > occurs there? > > Anyway it was pretty difficult to get xenomai 3.08 with gpio support > to work on the raspberry pi 3. > Took me a long time, and I rather stick with 3.0.8. > We use raspberry pi's in a course on the radboud university where > students get exercises in learning to use xenomai. > Switching to new version would mean lot of work for me. > Ok, I'll have a look asap in the coming days and follow up on this. -- Philippe.