Library prosa.model.processor.varspeed
In the following, we define a model of processors with variable execution
speeds.
NB: For now, the definition serves only to document how this can be done;
it is not actually used anywhere in the library.
Consider any type of jobs.
We define the state of a variable-speed processor at a given time to be
one of two possible cases: either a specific job is scheduled and
progresses with a specific speed, or the processor is idle.
Next, we define the semantics of the variable-speed processor state.
Consider any job j.
Definition varspeed_scheduled_on (s : processor_state) (_ : unit) : bool :=
match s with
| Idle ⇒ false
| Progress j' _ ⇒ j' == j
end.
match s with
| Idle ⇒ false
| Progress j' _ ⇒ j' == j
end.
If it is scheduled in state s, job j receives service proportional
to the speed recorded in the state.
Definition varspeed_service_in (s : processor_state) : nat :=
match s with
| Idle ⇒ 0
| Progress j' speed ⇒ if j' == j then speed else 0
end.
End Service.
match s with
| Idle ⇒ 0
| Progress j' speed ⇒ if j' == j then speed else 0
end.
End Service.
Finally, we connect the above definitions to the generic Prosa interface
for processor states.