rt_task_set_priority does not increase priority of other task

Jan Kiszka jan.kiszka at siemens.com
Thu Sep 17 13:51:46 CEST 2020

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? 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?


Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

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