Re: [Xenomai-help] Xenomai 2.0.1 - Posix Skin - realtime priorities - what I'm doing wrong?

[Ulrich Schwab <schwab@domain.hid>]

On Friday 09 December 2005 15:33, Paolo Gai wrote:
> Dear all,
>
> First of all, I would like to thank Philippe for the long and exaustive
> reply to my previous post about the scheduling example.
>
> I'm now trying the POSIX skin to write a very simple example using
> real-time priorities, RR and FIFO scheduling.
>
> The idea is that a high priority task creates two medium priority tasks
> (that just prints something using printf) and a low priority task (that
> prints a message).  The example is run twice, in one case the medium
> priority tasks have SCHED_FIFO, in another case they have SCHED_RR.
>
> I would expect that in both cases the two medium priority tasks would
> run printing their characters (either in a FIFO order or mixed when
> using RR), and at their end the low priority task would have run
> printing its message.
I did not look inside Your code, but if You are using printf the threads will 
be switched back to secondary domain (non-RT), this might screw up the order 
of scheduling.
You can try using a pipe to hand down the print output to a reader thread in 
secondary domain. This way Your threads in primary domain stay where they 
belong.

So long,
Ulrich Schwab

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