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SubjectRe: [RFC][PATCH 09/22] sched: add period support for -deadline tasks
On Thu, 2010-11-11 at 20:17 +0100, Peter Zijlstra wrote:
> On Fri, 2010-10-29 at 08:34 +0200, Raistlin wrote:
> > Make it possible to specify a period (different or equal than
> > deadline) for -deadline tasks.
> >
> I would expect it to be:
> runtime <= deadline <= period
Well, apart from that really unhappy comment/changelog, it should be
like that in the code, and if it's not, it is what I meant and I'll
change to that as soon as I can! :-)

Since you spotted it... The biggest issue here is admission control
test. Right now this is done against task's bandwidth, i.e.,
sum_i(runtime_i/period_i)<=threshold, but it is unfortunately wrong...
Or at least very, very loose, to the point of being almost useless! :-(

The more correct --in the sense that it at least yield a sufficient (not
necessary!) condition-- thing to do would be

So, what you think we should do? Can I go for this latter option?


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