Re: [Xenomai-core] use case: possible to boot Posix subsystem in <50ms and then Linux?

[Philippe Gerum <rpm@xenomai.org>]

On Fri, 2009-03-27 at 16:41 +0100, Peter Wächtler wrote:
> Am Friday 27 March 2009 15:53:02 schrieb Gilles Chanteperdrix:
> >
> > Xenomai kernel-space support is started somewhere in the middle of the
> > boot process, so, you can probably start kernel-space applications at
> > that time. User-space only works when init has been started, which
> > happens a bit later during the boot process. But you can start Xenomai
> > applications before all the system services have been started.
> >
> 
> I think the fundamental question is: does Adeos provide a scheduler? 
> 

No it does not. Not the kind of scheduler you seem to be thinking of
actually; it only "schedules" interrupt and trap events. Not tasks.

> And I guess the answer is yes, at least "Life-with-Adeos" doc mentions
> primary and secondary execution modes/domains.
> 

This is dealt with by the Xenomai nucleus. Adeos provides the simplistic
"domain" abstraction, and Xenomai derives the primary/secondary mode
abstractions on top of those.

> In the use case it would be necessary that OSEK subsystem is able to schedule 
> between a static number of preconfigured threads WITHOUT the precondition 
> that Linux is up and running.
> 

The way to do this would be to port the Xenomai nucleus and portions of
the POSIX skin over bare metal. I did exactly that once over an ARM ISS,
so this is indeed doable to bypass Linux. The point is: this needs a
full-fledge Xenomai port, a bit like the Xenomai event-driven simulator
interfaces to our RTOS core.

> >
> > As a side note, I have a question for the automotive industry people.
> > Would there be an interest in developing an OSEK skin for Xenomai? I
> > have been thinking about that for some time, but still have not found
> > time to start the job. I have read the OSEK spec, and found the
> > interface pretty simple (though some part of the job has to be done
> > offline, and annoyingly need to read XML files). The OSEK com spec, on
> > the other hand, looks rather scary.
> 
> There are open source OSEK implementations. AFAIK, all far from completeness.
> 
> You can start with
> http://opensek.sourceforge.net/
> 
> or have a look at the list at 
> http://en.wikipedia.org/wiki/OSEK
> 
> 	Peter
> 
> _______________________________________________
> Xenomai-core mailing list
> Xenomai-core@domain.hid
> https://mail.gna.org/listinfo/xenomai-core
-- 
Philippe.