Hello,
On 31/07/18 15:47, Rúben Gonçalves (1150785) wrote:
When making some experiments to the behaviour of RTEMS in SMP
configured with EDF and Rate Monotonic Manager we also noticed that
when a *periodic task* tries to obtain a semaphore created with the
Multiprocessor Resource Sharing Protocol (MrsP) the application
returns the status code "RTEMS_INVALID_PRIORITY".
We presume this is due to the fact that MrsP semaphore obtain function
tries to raise the priority of the task to the previously defined
priority ceiling and since the current priority is given by EDF (in a
way don't understand) (using the rate monotonic) the function is not
implemented to deal with that.
Does it make sense? Is it any accurate?
the EDF scheduler uses the deadline of a task to determine its priority.
The earlier the deadline the higher the priority (lower priority value).
The priorities associated with a deadline are higher than the priorities
which can be specified by the normal API.
If not, how can MrsP be correctly used with these configurations?
This is currently an unsupported use case. You can use the OMIP mutexes
together with the EDF scheduler. Are there schedulability analysis
results for MrsP + EDF?
Maybe the MrsP implementation can be changed to use the highest priority
of the executing thread and the mutex object.
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.hu...@embedded-brains.de
PGP : Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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