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.

Harco

Jan



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