------------------------------------------------------------------------------ ------------------------------------------------------------------------------ -- Cheddar is a GNU GPL real-time scheduling analysis tool. -- This program provides services to automatically check schedulability and -- other performance criteria of real-time architecture models. -- -- Copyright (C) 2002-2023, Frank Singhoff, Alain Plantec, Jerome Legrand, -- Hai Nam Tran, Stephane Rubini -- -- The Cheddar project was started in 2002 by -- Frank Singhoff, Lab-STICC UMR 6285, Université de Bretagne Occidentale -- -- Cheddar has been published in the "Agence de Protection des Programmes/France" in 2008. -- Since 2008, Ellidiss technologies also contributes to the development of -- Cheddar and provides industrial support. -- -- The full list of contributors and sponsors can be found in README.md -- -- This program is free software; you can redistribute it and/or modify -- it under the terms of the GNU General Public License as published by -- the Free Software Foundation; either version 2 of the License, or -- (at your option) any later version. -- -- This program is distributed in the hope that it will be useful, -- but WITHOUT ANY WARRANTY; without even the implied warranty of -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -- GNU General Public License for more details. -- -- You should have received a copy of the GNU General Public License -- along with this program; if not, write to the Free Software -- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA -- -- -- Contact : cheddar@listes.univ-brest.fr -- ------------------------------------------------------------------------------ -- Last update : -- $Rev$ -- $Date$ -- $Author: singhoff $ ------------------------------------------------------------------------------ ------------------------------------------------------------------------------ package body scheduler.dynamic_priority.muf.laxity_based is procedure initialize (a_scheduler : in out laxity_muf_scheduler) is begin reset (a_scheduler); a_scheduler.parameters.scheduler_type := maximum_urgency_first_based_on_laxity_protocol; end initialize; function copy (a_scheduler : in laxity_muf_scheduler) return generic_scheduler_ptr is ptr : muf_scheduler_ptr; begin ptr := new laxity_muf_scheduler; ptr.parameters := a_scheduler.parameters; ptr.previously_elected := a_scheduler.previously_elected; return generic_scheduler_ptr (ptr); end copy; procedure do_election (my_scheduler : in out laxity_muf_scheduler; si : in out scheduling_information; result : in out scheduling_sequence_ptr; msg : in out Unbounded_String; current_time : in Natural; processor_name : in Unbounded_String; address_space_name : in Unbounded_String; core_name : in Unbounded_String; options : in scheduling_option; event_to_generate : in time_unit_event_type_boolean_table; elected : in out tasks_range; no_task : in out Boolean) is smallest_laxity : Natural := Natural'last; laxity : Natural := 0; i : tasks_range := 0; almost_one_task : Boolean := False; is_ready : Boolean := False; begin -- Find the first ready task and assume we'll run this one -- loop if not si.tcbs (i).already_run_at_current_time then if (si.tcbs (i).tsk.cpu_name = processor_name) then if check_core_assignment (my_scheduler, si.tcbs (i)) then -- Compute current laxity -- laxity := dynamic_priority_tcb_ptr (si.tcbs (i)).dynamic_deadline - si.tcbs (i).rest_of_capacity; -- Is the task ready to run ? -- if (si.tcbs (i).wake_up_time <= current_time) and (si.tcbs (i).rest_of_capacity /= 0) then check_jitter (si.tcbs (i), current_time, si.tcbs (i).is_jitter_ready); if (options.with_jitters = False) or (si.tcbs (i).is_jitter_ready) then if (options.with_offsets = False) or check_offset (si.tcbs (i), current_time) then if (options.with_precedencies = False) or check_precedencies (si, current_time, si.tcbs (i)) then if options.with_resources then check_resource (my_scheduler, si, result, current_time, si.tcbs (i), is_ready, event_to_generate); else is_ready := True; end if; if is_ready then almost_one_task := True; smallest_laxity := laxity; elected := i; end if; end if; end if; end if; end if; end if; end if; end if; i := i + 1; exit when si.tcbs (i) = null; end loop; if not almost_one_task then no_task := True; else no_task := False; -- Let see now if some more urgent/critical task exists -- i := 0; loop if (si.tcbs (i).tsk.cpu_name = processor_name) then -- Compute current laxity -- laxity := dynamic_priority_tcb_ptr (si.tcbs (i)).dynamic_deadline - si.tcbs (i).rest_of_capacity; -- Is the task ready to run ? -- if (si.tcbs (i).wake_up_time <= current_time) and (si.tcbs (i).rest_of_capacity /= 0) then if (options.with_offsets = False) or check_offset (si.tcbs (i), current_time) then if (options.with_precedencies = False) or check_precedencies (si, current_time, si.tcbs (i)) then -- Select according to the laxity, criticality and --priority -- -- First case : we find a more critical task -- if (si.tcbs (i).tsk.criticality > si.tcbs (elected).tsk.criticality) then smallest_laxity := laxity; elected := i; else -- Second case : we find a more urgent task -- if (si.tcbs (i).tsk.criticality = si.tcbs (elected).tsk.criticality) and (laxity < smallest_laxity) then smallest_laxity := laxity; elected := i; else -- Last case : we find a task with a highiest --priority -- if (si.tcbs (i).tsk.criticality = si.tcbs (elected).tsk.criticality) and (laxity = smallest_laxity) and (si.tcbs (i).tsk.priority > si.tcbs (elected).tsk.priority) then smallest_laxity := laxity; elected := i; end if; end if; end if; end if; end if; end if; end if; i := i + 1; exit when si.tcbs (i) = null; end loop; -- last time unit : compute dynamic deadline for periodic task -- if (si.tcbs (elected).rest_of_capacity = 1) and (si.tcbs (elected).tsk.task_type = periodic_type) then dynamic_priority_tcb_ptr (si.tcbs (elected)).dynamic_deadline := dynamic_priority_tcb_ptr (si.tcbs (elected)).dynamic_deadline + periodic_task_ptr (si.tcbs (elected).tsk).period; end if; end if; end do_election; end scheduler.dynamic_priority.muf.laxity_based;