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/*
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 * Project: S.Ha.R.K.
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 *
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 * Coordinators:
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 *   Giorgio Buttazzo    <giorgio@sssup.it>
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 *   Paolo Gai           <pj@gandalf.sssup.it>
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 *
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 * Authors     :
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 *   Paolo Gai           <pj@gandalf.sssup.it>
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 *   Massimiliano Giorgi <massy@gandalf.sssup.it>
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 *   Luca Abeni          <luca@gandalf.sssup.it>
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 *   (see the web pages for full authors list)
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 *
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 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
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 *
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 * http://www.sssup.it
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 * http://retis.sssup.it
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 * http://shark.sssup.it
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 */
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/**
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 ------------
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 CVS :        $Id: cbs.h,v 1.4 2003-05-05 07:31:12 pj Exp $
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 File:        $File$
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 Revision:    $Revision: 1.4 $
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 Last update: $Date: 2003-05-05 07:31:12 $
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 ------------
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 This file contains the aperiodic server CBS (Total Bandwidth Server)
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 Title:
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   CBS (Constant Bandwidth Server)
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 Task Models Accepted:
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   SOFT_TASK_MODEL - Soft Tasks
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     wcet field is ignored
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     met field must be != 0
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     period field must be != 0
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     periodicity field can be either PERIODIC or APERIODIC
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     arrivals field can be either SAVE or SKIP
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 Description:
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   This module schedule his tasks following the CBS scheme.
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   (see Luca Abeni and Giorgio Buttazzo,
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        "Integrating Multimedia Applications in Hard Real-Time Systems"
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        Proceedings of the IEEE Real-Time Systems Symposium, Madrid, Spain,
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        December 1998)
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   The tasks are inserted in an EDF level (or similar) with a JOB_TASK_MODEL,
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   and the CBS level expects that the task is scheduled with the absolute
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   deadline passed in the model.
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   The task guarantee is based on the factor utilization approach.
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 Exceptions raised:
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   XUNVALID_GUEST
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     This level doesn't support guests. When a guest operation
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     is called, the exception is raised.
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   These exceptions are pclass-dependent...
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   XDEADLINE_MISS
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     If a task miss his deadline, the exception is raised.
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     Normally, a CBS task can't cause the raise of such exception because
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     if it really use more time than declared the deadline is postponed.
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 Restrictions & special features:
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   - This level doesn't manage the main task.
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   - At init time we have to specify:
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       . guarantee check
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          (when all task are created the system will check that the task_set
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          will not use more than the available bandwidth)
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   - A function to return the used bandwidth of the level is provided.
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   - A function to return the pending activations of the task.
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**/
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/*
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 * Copyright (C) 2000 Paolo Gai
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 */
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#ifndef __CBS_H__
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#define __CBS_H__
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#include <ll/ll.h>
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#include <kernel/config.h>
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#include <sys/types.h>
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#include <kernel/types.h>
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#include "ll/sys/cdefs.h"
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__BEGIN_DECLS
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/*+ flags... +*/
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#define CBS_DISABLE_ALL           0  /*+ Task Guarantee enabled +*/
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#define CBS_ENABLE_GUARANTEE      1  /*+ Task Guarantee enabled +*/
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#define CBS_ENABLE_ALL            1
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/*+ Registration function:
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    int flags     Options to be used in this level instance...
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    LEVEL master  the level that must be used as master level for the
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                  CBS tasks
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    returns the level number at which the module has been registered.
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+*/
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LEVEL CBS_register_level(int flags, LEVEL master);
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/*+ Returns the used bandwidth of a level +*/
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bandwidth_t CBS_usedbandwidth(LEVEL l);
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/*+ Returns the number of pending activations of a task.
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    No control is done if the task is not a CBS task! +*/
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int CBS_get_nact(LEVEL l, PID p);
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__END_DECLS
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#endif