MARTE11 — GRM:Support for Time table driven schedules

MARTE, formal/2009-11-02, GRM chapter, pag 96-97, enhancement

GRM:Support for Time table driven schedules.

Having the opaque expression attribute "schedule" in the Scheduler in GRM lead to a very open way of expressing fixed schedules or non-traditional scheduling policies. This is the case of time triggered sets of tasks in particular, but also of any form of table driven schedule. Following a general approach but formalizing the way of expressing schedules as a set of labeled timed windows would make the exchange of information between strict time triggered platforms design intent and its corresponding analysis models easier and in a standardized way.

An alternative to study may be formalizing the attribute “schedule” of a scheduler to include at least the frame_cycle_time, and the list of “windows” or “time_slots” to be managed as schedulable resources. To do this the easiest way may be to make them part of a list inside the schedule indexed by a key that match the scheduling parameters field of the schedulable resources that are attached to the scheduler.

The current structure grants the designer the capacity of describing the schedule to use
by means of an opaque expression, and the scheduling parameters for the table driven
policy in the way of an open format string. In order to facilitate the description of more
precise and standardized schedules, a concrete format for these types has been
proposed.
The necessary attributes are presented. For the scheduler the attribute “schedule” will
be formalized to include at least the frame_cycle_time, and the list of “windows” or
“time_slots” for the partitions, for doing this there are two alternatives (a) make them part
of a list inside the schedule indexed by a key that match the scheduling parameters field
of the schedulable resources that are attached to the scheduler, or (b) compose the list
by considering the allocated schedulable resources with their corresponding
schedulingParameters, changing the current type string used for the TableEntry field into
the necessary time_slot data type tuple.
Alternative (a) is easier to set into the standard and the models are easier to check for
consistency, hence is the one proposed. It comprises the formalization of the opaque
expression used for the attribute “schedule” into a structure like the one shown in the
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