Constrained deadlines in SMP

Sebastian Huber sebastian.huber at
Wed Aug 1 05:33:03 UTC 2018

On 31/07/18 15:34, Rúben Gonçalves (1150785) wrote:
> We  are currently running some experiments with RTEMS in SMP and were 
> faced with some problems. We were hoping someone with a better 
> understanding of the  operating system mechanisms could help us figure 
> out what to do.
> We are using the EDF (Earliest Deadline First) scheduler for RTEMS-SMP 
> and the Rate Monotonic Manager.
> We were trying to run some periodic tasks that have a constrained 
> deadline. (e.g., Task1 -  Deadline: 30 ticks - Period: 1000 ticks)

The use case of constrained deadlines is currently not supported. I 
think we would have to modify the rate monotonic objects to support it 
or create a new object. You have to combine a normal timer for the 
period with a deadline initialization at period begin.

Sebastian Huber, embedded brains GmbH

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