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Subject: Re: periods and deadlines in SCHED_DEADLINE
From: Raistlin <raistlin@linux.it>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
       Song Yuan <song.yuan@ericsson.com>,
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On Fri, 2010-07-09 at 16:30 +0200, Peter Zijlstra wrote:
> On Fri, 2010-07-09 at 15:38 +0200, Raistlin wrote:
> >=20
> > Therefore, here it is my proposal:
> >  - if the programmer specify both period and deadline, I act as above,
> >    running the _only_necessary_ test in the kernel, assuming that
> >    userspace performed some other kind of (correct!) admission test by
> >    its own, or that it is cool with missing some deadlines... What do
> >    you think?
>=20
> It would be good to provide room in the interface to improve upon this
> situation.
>=20
Well, room is already there, problem is decide how to use it.

> One thing we could do, although this would make the proposed scheduler a
> wee bit more complex, is split between hard and soft realtime. Only
> accept P=3D=3Drel_D for hard, and schedule the soft tasks in the hard sla=
ck
> or something like that.
>=20
As said in the other mail, this could be done, just let me know as much
as you can how you think it should happen (scheduling class, scheduling
policy, two (or more) separate queues, ecc.

Btw, Dhaval introduced me to the obscure world of IRC... I am (if
everything worked! :-P) dariof on #sched and/or #sched-rt, so feel free
to contact me even there, if at te PC I'll be glad to discuss even
there! :-D

Thanks and regards,
Dario

--=20
<<This happens because I choose it to happen!>> (Raistlin Majere)
----------------------------------------------------------------------
Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa  (Italy)

http://blog.linux.it/raistlin / raistlin@ekiga.net /
dario.faggioli@jabber.org

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