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210 | ------------------------------------------------------------------------------
------------------------------------------------------------------------------
-- 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: 4589 $
-- $Date: 2023-09-29 16:02:19 +0200 (ven., 29 sept. 2023) $
-- $Author: singhoff $
------------------------------------------------------------------------------
------------------------------------------------------------------------------
with xml_tag; use xml_tag;
with double_util; use double_util;
with translate; use translate;
with unbounded_strings; use unbounded_strings;
with systems; use systems;
with Ada.Tags; use Ada.Tags;
with Text_IO; use Text_IO;
with debug; use debug;
package body scheduler.dynamic_priority.edf is
procedure initialize (a_scheduler : in out edf_scheduler) is
begin
reset (a_scheduler);
a_scheduler.parameters.scheduler_type :=
earliest_deadline_first_protocol;
end initialize;
function copy
(a_scheduler : in edf_scheduler) return generic_scheduler_ptr
is
ptr : edf_scheduler_ptr;
begin
ptr := new edf_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 edf_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_deadline : Natural := Natural'last;
i : tasks_range := 0;
is_ready : Boolean := False;
previous_task_can_be_run : Boolean := False;
begin
put_debug ("Call Do_Election: EDF");
loop
if (si.tcbs (i).tsk.cpu_name = processor_name) then
dynamic_priority_tcb_ptr (si.tcbs (i)).dynamic_deadline :=
si.tcbs (i).wake_up_time + si.tcbs (i).tsk.deadline;
end if;
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
if (si.tcbs (i).wake_up_time <= current_time) and
(si.tcbs (i).rest_of_capacity /= 0)
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
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 i = my_scheduler.previously_elected then
previous_task_can_be_run := True;
end if;
if
(dynamic_priority_tcb_ptr (si.tcbs (i))
.dynamic_deadline <
smallest_deadline)
then
smallest_deadline :=
dynamic_priority_tcb_ptr (si.tcbs (i))
.dynamic_deadline;
elected := i;
end if;
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 smallest_deadline = Natural'last then
no_task := True;
else
no_task := False;
end if;
-- By default, as task are sorted in the set according to their name
-- when we have two tasks with the same absolute deadline, we choose the first one
-- in the task set, i.e. the task with the smallest name.
-- This strategy can be useful has it provides a simple mean to introduce a
-- tie break as a kind of fixed priority.
-- However, it may introduce an extra preemption.
-- If we want to reduce preemption number as much as possible, in this case
-- we select the previous task ... in this task can be run again !
--
if options.with_minimize_preemption and previous_task_can_be_run then
if dynamic_priority_tcb_ptr
(si.tcbs (my_scheduler.previously_elected))
.dynamic_deadline =
smallest_deadline
then
elected := my_scheduler.previously_elected;
put_debug ("Call Do_Election: EDF : Minimize preemption");
end if;
end if;
put_debug ("Call Do_Election: EDF : Elected : " & elected'img);
end do_election;
end scheduler.dynamic_priority.edf;
|