Library prosa.model.priority.rate_monotonic

Require Export prosa.model.priority.classes.
Require Export prosa.model.task.arrival.sporadic.

Rate-Monotonic Fixed-Priority Policy

We define the notion of rate-monotonic task priorities for sporadic tasks, i.e., the classic FP policy in which sporadic tasks are prioritized in order of their minimum inter-arrival times (or periods).

#[export] Instance RM (Task : TaskType) `{SporadicModel Task} : FP_policy Task :=
{
hep_task (tsk1 tsk2 : Task) := task_min_inter_arrival_time tsk1 ≤ task_min_inter_arrival_time tsk2
}.

In this section, we prove a few basic properties of the RM policy.

Section Properties.

Consider sporadic tasks...

Context {Task : TaskType}.
Context `{SporadicModel Task}.

...and jobs stemming from these tasks.

Context {Job : JobType}.
Context `{JobTask Job Task}.

RM is reflexive.

Lemma RM_is_reflexive : reflexive_priorities.
Proof. by move⇒ ?; rewrite /hep_job_at /JLFP_to_JLDP /hep_job /FP_to_JLFP /hep_task /RM. Qed.

RM is transitive.

Lemma RM_is_transitive : transitive_priorities.
Proof. by intros t y x z; apply leq_trans. Qed.

RM is total.

Lemma RM_is_total : total_priorities.
Proof. by move⇒ t j1 j2; apply leq_total. Qed.

End Properties.

We add the above lemmas into a "Hint Database" basic_rt_facts, so Coq will be able to apply them automatically.

Global Hint Resolve
     RM_is_reflexive
     RM_is_transitive
     RM_is_total
  : basic_rt_facts.