[Xenomai] [PATCH] copperplate/mercury: introduce weak function to get OS max thread priority

Ronny Meeus ronny.meeus at gmail.com
Sat Dec 3 21:39:46 CET 2016


On Sat, Dec 3, 2016 at 6:18 PM, Philippe Gerum <rpm at xenomai.org> wrote:
> On 11/30/2016 08:30 AM, Ronny Meeus wrote:
>> This patch introduces a weak function in the mercury copperplate code
>> that allows to put an upper limit on the priority used by the created thread
>> objects.
>>
>> Before this patch the complete OS scheduler's FIFO range was used and it was
>> not possible to restrict it. Restricting it can be useful in case other
>> activities (typically platform related things) need to get a higher priority
>> than the application threads.
>>
>> The example below shows what needs to be implemented in the application to
>> restrict the range.
>
> This looks weird. Any reason not to fix up the priority of your
> application threads?
>

Philippe,

this is not only about the application threads. We also need to lower
the priorities
used by the copperplate for the timer-thread and the task-lock priority.
The reason for this is that we need to run certain Linux kernel
threads at a higher
priority than any of the application threads, including Xenomai.


Ronny

> --
> Philippe.



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