RTEMS on multi-core/multi-processor

Joel Sherrill joel.sherrill at OARcorp.com
Mon Jun 9 14:57:58 UTC 2008

Thomas Doerfler wrote:
> Tobias,
> AFAIK currently RTEMS has no awareness of multicore processors. If you
> have multiple execution units in your system, you might run a separate
> instance of RTEMS on each of these cores, and couple them through
> "global" OS objects like semaphores, message queues etc. Then your
> configuration is similar to a system of multiple, loosely coupled
> processor systems.
Right.  But you can use essentially the same image on
every CPU if you want.  If there is a way to see which
CPU you are on, then you can use the CPU id number
to determine which tasks to run by default on each node.

I have also seen systems which use some mechanism
to turn tasks off on one node and on another.  If your
intertask communications mechanism is configured
as global, then the tasks effectively migrated.  Remember
the underlying comm/sync objects did not though.

So in the simplest sense you have absolute control
over which tasks are on which node because you
manually placed them there.

> wkr,
> Thomas.
> Tobias Schoofs schrieb:
>> Dear colleagues,
>> how does RTEMS behave on multi-core/multi-processor hardware? I know
>> that tasks are statically bound to cores during compilation; but what is
>> the policy of this binding? Is there a way to influence the decision?
>> Thanks a lot,
>> Tobias
>> _______________________________________________
>> rtems-users mailing list
>> rtems-users at rtems.com
>> http://rtems.rtems.org/mailman/listinfo/rtems-users
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Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill at OARcorp.com        On-Line Applications Research
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