> Hi James,
>
> On 15/11/10 19:37, James H. Anderson wrote:
> [...]
>>>> The problem the stochastic execution time model tries to address is
>>>> the
>>>> WCET computation mess, WCET computation is hard and often overly
>>>> pessimistic, resulting in under-utilized systems.
>>>>
>>> I know, and it's very reasonable. The point I'm trying to make is that
>>> resource reservation tries to address the very same issue.
>>> I am all but against this model, just want to be sure it's not too much
>>> in conflict to the other features we have, especially with resource
>>> reservation. Especially considering that --if I got the whole thing
>>> about this scheduler right-- resource reservation is something we
>>> really
>>> want, and I think UNC people would agree here, since I heard Bjorn
>>> stating this very clear both in Dresden and in Dublin. :-)
>>>
>>> BTW, I'm adding them to the Cc, seems fair, and more useful than all
>>> this speculation! :-P
>>>
>>> Bjorn, Jim, sorry for bothering. If you're interested, this is the very
>>> beginning of the whole thread:
>>>
http://lkml.org/lkml/2010/10/29/67
> [...]
>> If you're talking about our most recent "stochastic" paper, it is about
>> supporting
>> soft real-time task systems on a multiprocessor where resource
>> reservations are
>> used. The main result of the paper is that if you provision the
>> reservation for a
>> task slightly higher than it's average-case execution time, and if you
>> use a
>> scheduling algorithm (like global EDF) that ensures bounded tardiness
>> (w.r.t.
>> these reservations), then the task's expected tardiness will be bounded
>> and the
>> expected bound does not depend on worst-case execution times. I'm not
>> sure if
>> slack-reallocation methods have come up in this discussion (sorry, I'm
>> really
>> pressed for time and didn't look), but we didn't get into that in our
>> paper.
> So, if I understand well (sorry, I am just trying to make a short
> summary to check if we are aligned) your analysis is similar to the
> one presented in the papers I mentioned earlier in this thread
> (different stochastic modelling, but similar approach): you analyse a
> reservation in isolation and you provide some stochastic tardiness
> guarantees based on an (e_i, p_i) service model.... Right?
