106 lines
2.7 KiB
Plaintext
106 lines
2.7 KiB
Plaintext
open Scheduler_data
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open Extern
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fun select_aux(ts:task_status; ta:task_attributes;tid:int ;acc:select_acc)
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returns (acc_o:select_acc)
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let
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acc_o =
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if (ts.status = Ready) and (ta.period < acc.speriod) then
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{ tid = tid; speriod = ta.period }
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else acc
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tel
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fun select_one_task(ts:task_status^ntasks) returns(selected:int)
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var tmp : select_acc ;
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let
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tmp = foldi<<ntasks>> select_aux (ts,tasks,{ tid = ntasks; speriod = int_max }) ;
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selected = tmp.tid ;
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tel
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fun start_inst(current_date:int;tsi:task_status;ta:task_attributes)
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returns (tso:task_status)
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var c : bool ;
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let
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c = (current_date-ta.first_start)%ta.period = 0 ;
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tso = merge c
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(true -> {
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status = Ready;
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current_deadline =
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(current_date when c) + (ta.deadline when c);
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left = (ta.capacity when c)
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})
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(false -> tsi whenot c)
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tel
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fun update_selected(ts:task_status;selected:int;tid:int) returns (tso:task_status)
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let
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tso =
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if tid = selected then
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{ ts with .status = Running }
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else ts
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tel
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fun rate_monotonic(ts:task_status^ntasks) returns (tso:task_status^ntasks)
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var selected : int ;
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let
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selected = select_one_task(ts) ;
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tso = mapi<<ntasks>> update_selected (ts, selected^ntasks) ;
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tel
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fun check_deadline(current_date:int; tsi:task_status; tid:int)
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returns (tso:task_status)
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var c: bool ;
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let
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c = (tsi.status = Ready)
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and (tsi.current_deadline = current_date) ;
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() = deadline_miss_log(current_date when c, tid when c) ;
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tso = if c then { tsi with .status = Waiting} else tsi ;
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tel
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fun simulate(tsi:task_status)
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returns (o:task_status)
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let
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o =
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if tsi.status = Running then
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if tsi.left <=1 then
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(* Normal termination, move to Waiting state *)
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{ tsi with .status = Waiting }
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else
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(* No termination, yet *)
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{
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status = Ready;
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current_deadline = tsi.current_deadline ;
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left = tsi.left - 1
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}
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else tsi
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tel
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fun scheduler(si:scheduler_state) returns (so:scheduler_state)
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var
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new_date : int ;
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tmp1,tmp2,tmp3,fin: task_status^ntasks ;
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let
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new_date = si.current_date + 1 ; (* advance time by 1 *)
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tmp1 = map <<ntasks>> simulate (si.tasks) ;
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tmp2 = mapi<<ntasks>> check_deadline (new_date^ntasks,tmp1);
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tmp3 = map <<ntasks>> start_inst (new_date^ntasks,tmp2,tasks);
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fin = rate_monotonic(tmp3) ; (* scheduling policy *)
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so = { current_date = new_date; tasks = fin }
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tel
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const init_sstate : scheduler_state = {
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current_date = -1 ;
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tasks = {
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status=Waiting;current_deadline=0;left=0
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}^2
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}
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node main() returns ()
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var sstate, new_sstate : scheduler_state ;
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let
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new_sstate = scheduler(sstate) ;
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sstate = init_sstate fby new_sstate ;
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() = print_scheduler_state(new_sstate) ;
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tel
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