Library prosa.classic.analysis.uni.susp.dynamic.jitter.taskset_rta
Require Import prosa.classic.util.all.
Require Import prosa.classic.model.priority prosa.classic.model.suspension.
Require Import prosa.classic.model.arrival.basic.task prosa.classic.model.arrival.basic.job
prosa.classic.model.arrival.basic.task_arrival prosa.classic.model.arrival.basic.arrival_sequence.
Require Import prosa.classic.model.arrival.jitter.job.
Require Import prosa.classic.model.schedule.uni.response_time.
Require Import prosa.classic.model.schedule.uni.susp.schedule prosa.classic.model.schedule.uni.susp.platform
prosa.classic.model.schedule.uni.susp.valid_schedule.
Require Import prosa.classic.model.schedule.uni.jitter.valid_schedule.
Require Import prosa.classic.analysis.uni.susp.dynamic.jitter.rta_by_reduction
prosa.classic.analysis.uni.susp.dynamic.jitter.jitter_taskset_generation
prosa.classic.analysis.uni.susp.dynamic.jitter.taskset_membership.
From mathcomp Require Import ssreflect ssrbool eqtype ssrnat seq fintype bigop.
(* In this file we use the reduction to jitter-aware schedule to analyze
individual tasks using RTA. *)
Module TaskSetRTA.
Import SporadicTaskset Suspension Priority ValidSuspensionAwareSchedule
ScheduleWithSuspensions ResponseTime PlatformWithSuspensions
TaskArrival ValidJitterAwareSchedule RTAByReduction TaskSetMembership.
Module ts_gen := JitterTaskSetGeneration.
Module job_susp := Job.
Module job_jitter := JobWithJitter.
(* In this section, we are going to assume we have obtained response-time
bounds for high-priority tasks and then use the reduction to infer a
response-time bound for a particular task. *)
Section PerTaskAnalysis.
Context {Task: eqType}.
Variable task_cost: Task → time.
Variable task_period: Task → time.
Variable task_deadline: Task → time.
Context {Job: eqType}.
Variable job_arrival: Job → time.
Variable job_deadline: Job → time.
Variable job_task: Job → Task.
Require Import prosa.classic.model.priority prosa.classic.model.suspension.
Require Import prosa.classic.model.arrival.basic.task prosa.classic.model.arrival.basic.job
prosa.classic.model.arrival.basic.task_arrival prosa.classic.model.arrival.basic.arrival_sequence.
Require Import prosa.classic.model.arrival.jitter.job.
Require Import prosa.classic.model.schedule.uni.response_time.
Require Import prosa.classic.model.schedule.uni.susp.schedule prosa.classic.model.schedule.uni.susp.platform
prosa.classic.model.schedule.uni.susp.valid_schedule.
Require Import prosa.classic.model.schedule.uni.jitter.valid_schedule.
Require Import prosa.classic.analysis.uni.susp.dynamic.jitter.rta_by_reduction
prosa.classic.analysis.uni.susp.dynamic.jitter.jitter_taskset_generation
prosa.classic.analysis.uni.susp.dynamic.jitter.taskset_membership.
From mathcomp Require Import ssreflect ssrbool eqtype ssrnat seq fintype bigop.
(* In this file we use the reduction to jitter-aware schedule to analyze
individual tasks using RTA. *)
Module TaskSetRTA.
Import SporadicTaskset Suspension Priority ValidSuspensionAwareSchedule
ScheduleWithSuspensions ResponseTime PlatformWithSuspensions
TaskArrival ValidJitterAwareSchedule RTAByReduction TaskSetMembership.
Module ts_gen := JitterTaskSetGeneration.
Module job_susp := Job.
Module job_jitter := JobWithJitter.
(* In this section, we are going to assume we have obtained response-time
bounds for high-priority tasks and then use the reduction to infer a
response-time bound for a particular task. *)
Section PerTaskAnalysis.
Context {Task: eqType}.
Variable task_cost: Task → time.
Variable task_period: Task → time.
Variable task_deadline: Task → time.
Context {Job: eqType}.
Variable job_arrival: Job → time.
Variable job_deadline: Job → time.
Variable job_task: Job → Task.
Basic Setup & Setting
(* Let ts be any task set with constrained deadlines. *)
Variable ts: seq Task.
Hypothesis H_constrained_deadlines:
constrained_deadline_model task_period task_deadline ts.
(* Consider any consistent, duplicate-free job arrival sequence... *)
Variable arr_seq: arrival_sequence Job.
Hypothesis H_arrival_times_are_consistent:
arrival_times_are_consistent job_arrival arr_seq.
Hypothesis H_arrival_sequence_is_a_set: arrival_sequence_is_a_set arr_seq.
(* ...with sporadic arrivals... *)
Hypothesis H_sporadic_arrivals:
sporadic_task_model task_period job_arrival job_task arr_seq.
(* ...and in which all jobs come from the task set. *)
Hypothesis H_jobs_come_from_taskset:
∀ j, arrives_in arr_seq j → job_task j \in ts.
(* Assume that job deadlines equal task deadlines. *)
Hypothesis H_job_deadline_eq_task_deadline:
∀ j, arrives_in arr_seq j → job_deadline j = task_deadline (job_task j).
(* Consider any job suspension times and task suspension bound. *)
Variable job_suspension_duration: job_suspension Job.
Variable task_suspension_bound: Task → time.
(* Assume any FP policy that is reflexive, transitive and total. *)
Variable higher_eq_priority: FP_policy Task.
Hypothesis H_priority_is_reflexive: FP_is_reflexive higher_eq_priority.
Hypothesis H_priority_is_transitive: FP_is_transitive higher_eq_priority.
Hypothesis H_priority_is_total: FP_is_total_over_task_set higher_eq_priority ts.
Let job_higher_eq_priority := FP_to_JLDP job_task higher_eq_priority.
(* Recall the definition of a valid suspension-aware and jitter-aware schedules. *)
Let is_valid_suspension_aware_schedule :=
valid_suspension_aware_schedule job_arrival arr_seq job_higher_eq_priority
job_suspension_duration.
Let is_valid_jitter_aware_schedule :=
valid_jitter_aware_schedule job_arrival arr_seq job_higher_eq_priority.
(* Also recall the definition of task response-time bound for given job cost and schedule. *)
Let is_task_response_time_bound_with job_cost sched :=
is_response_time_bound_of_task job_arrival job_cost job_task arr_seq sched.
Analysis Setup
(* Let tsk_i be any task to be analyzed. *)
Variable tsk_i: Task.
Hypothesis H_tsk_in_ts: tsk_i \in ts.
(* Recall the definition of higher-or-equal-priority tasks (other than tsk_i). *)
Let other_hep_task tsk_other := higher_eq_priority tsk_other tsk_i && (tsk_other != tsk_i).
(* Next, assume that for each of those higher-or-equal-priority tasks (other than tsk_i),
we know a response-time bound R that is valid across all suspension-aware schedules of ts. *)
Variable R: Task → time.
Hypothesis H_valid_response_time_bound_of_hp_tasks_in_all_schedules:
∀ job_cost sched,
is_valid_suspension_aware_schedule job_cost sched →
∀ tsk_hp,
tsk_hp \in ts →
other_hep_task tsk_hp →
is_task_response_time_bound_with job_cost sched tsk_hp (R tsk_hp).
(* Since this analysis is for constrained deadlines, also assume that
(R tsk_i) is no larger than the deadline of tsk_i. *)
Hypothesis H_R_le_deadline: R tsk_i ≤ task_deadline tsk_i.
Recall: Properties of Valid Jitter-Aware Jobs
(* Recall that a valid jitter-aware schedule must have positive job costs,... *)
Let job_cost_positive job_cost :=
∀ j, arrives_in arr_seq j → job_cost j > 0.
(* ...job costs that are no larger than the task costs... *)
Let job_cost_le_task_cost job_cost task_cost :=
∀ j,
arrives_in arr_seq j →
job_cost j ≤ task_cost (job_task j).
(* ...and job jitter no larger than the task jitter. *)
Let job_jitter_le_task_jitter job_jitter task_jitter :=
∀ j,
arrives_in arr_seq j →
job_jitter j ≤ task_jitter (job_task j).
(* This is summarized in the following predicate. *)
Definition valid_jobs_with_jitter job_cost job_jitter task_cost task_jitter :=
job_cost_positive job_cost ∧
job_cost_le_task_cost job_cost task_cost ∧
job_jitter_le_task_jitter job_jitter task_jitter.
Conclusion: Response-time Bound for Task tsk_i
(* Recall the parameters of the generated jitter-aware task set. *)
Let inflated_task_cost := ts_gen.inflated_task_cost task_cost task_suspension_bound tsk_i.
Let task_jitter := ts_gen.task_jitter task_cost higher_eq_priority tsk_i R.
(* By using a jitter-aware RTA, assume that we proved that (R tsk_i) is a valid
response-time bound for task tsk_i in any jitter-aware schedule of the same
arrival sequence. *)
Hypothesis H_valid_response_time_bound_of_tsk_i:
∀ job_cost job_jitter sched,
valid_jobs_with_jitter job_cost job_jitter inflated_task_cost task_jitter →
is_valid_jitter_aware_schedule job_cost job_jitter sched →
is_task_response_time_bound_with job_cost sched tsk_i (R tsk_i).
(* Next, consider any job cost function... *)
Variable job_cost: Job → time.
(* ...and let sched_susp be any valid suspension-aware schedule with those job costs. *)
Variable sched_susp: schedule Job.
Hypothesis H_valid_schedule: is_valid_suspension_aware_schedule job_cost sched_susp.
(* Assume that the job costs are positive... *)
Hypothesis H_job_cost_positive:
∀ j, arrives_in arr_seq j → job_cost j > 0.
(* ...and no larger than the task costs. *)
Hypothesis H_job_cost_le_task_cost:
∀ j,
arrives_in arr_seq j →
job_cost j ≤ task_cost (job_task j).
(* Also assume that job suspension times are bounded by the task suspension bounds. *)
Hypothesis H_dynamic_suspensions:
dynamic_suspension_model job_cost job_task job_suspension_duration task_suspension_bound.
(* Using the reduction to a jitter-aware schedule, we conclude that (R tsk_i) must
also be a response-time bound for task tsk_i in the suspension-aware schedule. *)
Theorem valid_response_time_bound_of_tsk_i:
is_task_response_time_bound_with job_cost sched_susp tsk_i (R tsk_i).
Proof.
unfold is_task_response_time_bound_with,
is_response_time_bound_of_task, is_response_time_bound_of_job in ×.
rename H_valid_response_time_bound_of_hp_tasks_in_all_schedules into RESPhp,
H_valid_response_time_bound_of_tsk_i into RESPi.
move: (H_valid_schedule) ⇒ [_ [_ [COMP _]]].
intros j ARRj JOBtsk.
(* First, rewrite the claim in terms of the *absolute* response-time bound (arrival + R) *)
remember (job_arrival j + R tsk_i) as ctime.
(* Now, we apply strong induction on the absolute response-time bound. *)
generalize dependent j.
induction ctime as [ctime IH] using strong_ind.
intros j ARRj JOBtsk EQc; subst ctime.
(* First, let's simplify the induction hypothesis. *)
have BEFOREok:
∀ j0,
arrives_in arr_seq j0 →
job_task j0 = tsk_i →
job_arrival j0 < job_arrival j →
completed_by job_cost sched_susp j0 (job_arrival j0 + R tsk_i);
[by ins; apply IH; try (by done); rewrite ltn_add2r | clear IH].
set actual_response_time :=
actual_response_time job_arrival job_task job_cost sched_susp R.
set inflated_job_cost :=
reduction.inflated_job_cost job_cost job_suspension_duration.
set job_jitter := reduction.job_jitter job_arrival job_task
higher_eq_priority job_cost j actual_response_time.
try ( apply valid_response_time_bound_in_sched_susp with
(task_period0 := task_period) (task_deadline0 := task_deadline)
(job_deadline0 := job_deadline) (job_task0 := job_task) (ts0 := ts)
(arr_seq0 := arr_seq) (higher_eq_priority0 := higher_eq_priority)
(job_suspension_duration0:=job_suspension_duration); try (by done) ) ||
apply valid_response_time_bound_in_sched_susp with
(task_period := task_period) (task_deadline := task_deadline)
(job_deadline := job_deadline) (job_task := job_task) (ts := ts)
(arr_seq := arr_seq) (higher_eq_priority := higher_eq_priority)
(job_suspension_duration:=job_suspension_duration); try (by done).
- by intros tsk_hp IN OHEP j'; apply RESPhp.
{
intros j0 ARR0 LT0 JOB0.
apply completion_monotonic with (t := job_arrival j0 + R tsk_i);
[ | by apply BEFOREok; rewrite // -JOBtsk].
by rewrite leq_add2l H_job_deadline_eq_task_deadline // JOB0 JOBtsk.
}
{
apply RESPi with (job_jitter := job_jitter); try (by done);
last by eapply reduction_prop.sched_jitter_is_valid; eauto 1.
repeat split; intros j' ARR.
- by eapply ts_membership_inflated_job_cost_positive; eauto 1.
- by eapply ts_membership_inflated_job_cost_le_inflated_task_cost;
eauto 1.
- by eapply ts_membership_job_jitter_le_task_jitter; eauto 1.
}
Qed.
End PerTaskAnalysis.
End TaskSetRTA.