[ECOS] Preemption in Bitmap Scheduler

[ECOS] Preemption in Bitmap Scheduler

[Potdar Smita]

I had a question about how preemption works in the
Bitmap scheduler of eCos. Since with this scheduler,
only one thread can exist at a particular priority
level, hence timeslicing is disabled. What about
preemption? Once a thread begins executing, does it
run to completion or can it be preempted by a higher
priority thread? Does eCos handle threads created
after the system starts working? If yes, how is this
done?

Thanks in advance.
Any help is greatly appreciated.


 
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[ECOS] Re: Preemption in Bitmap Scheduler

[Grant Edwards]

On 2007-03-21, Potdar Smita <sspotdar@yahoo.com> wrote:

> What about preemption?

It works just fine.

> Once a thread begins executing, does it run to completion or
> can it be preempted by a higher priority thread?

The latter.

> Does eCos handle threads created after the system starts
> working?

Of course.  There's no way to create a thread before the system
starts working.  I have worked with RTOSes where threads could
be declared statically, but eCos doesn't work that way: all
threads are created dynamically.

> If yes, how is this done?

you call cyg_thread_create().

-- 
Grant Edwards                   grante             Yow!  ... I see TOILET
                                  at               SEATS...
                               visi.com            


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