WebSVN - shark - Blame - Rev 80 - /shark/trunk/include/modules/cbs.h

Rev	Author	Line No.	Line
2	pj	1	/*
		2	* Project: S.Ha.R.K.
		3	*
		4	* Coordinators:
		5	* Giorgio Buttazzo <giorgio@sssup.it>
		6	* Paolo Gai <pj@gandalf.sssup.it>
		7	*
		8	* Authors :
		9	* Paolo Gai <pj@gandalf.sssup.it>
		10	* Massimiliano Giorgi <massy@gandalf.sssup.it>
		11	* Luca Abeni <luca@gandalf.sssup.it>
		12	* (see the web pages for full authors list)
		13	*
		14	* ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
		15	*
		16	* http://www.sssup.it
		17	* http://retis.sssup.it
		18	* http://shark.sssup.it
		19	*/
		20
		21
		22	/**
		23	------------
80	pj	24	CVS : $Id: cbs.h,v 1.3 2003-03-13 13:39:04 pj Exp $
2	pj	25
		26	File: $File$
80	pj	27	Revision: $Revision: 1.3 $
		28	Last update: $Date: 2003-03-13 13:39:04 $
2	pj	29	------------
		30
		31	This file contains the aperiodic server CBS (Total Bandwidth Server)
		32
		33	Title:
		34	CBS (Constant Bandwidth Server)
		35
		36	Task Models Accepted:
		37	SOFT_TASK_MODEL - Soft Tasks
		38	wcet field is ignored
		39	met field must be != 0
		40	period field must be != 0
		41	periodicity field can be either PERIODIC or APERIODIC
		42	arrivals field can be either SAVE or SKIP
		43
		44	Description:
		45	This module schedule his tasks following the CBS scheme.
		46	(see Luca Abeni and Giorgio Buttazzo,
		47	"Integrating Multimedia Applications in Hard Real-Time Systems"
		48	Proceedings of the IEEE Real-Time Systems Symposium, Madrid, Spain,
		49	December 1998)
		50
		51	The tasks are inserted in an EDF level (or similar) with a JOB_TASK_MODEL,
		52	and the CBS level expects that the task is scheduled with the absolute
		53	deadline passed in the model.
		54
		55	The task guarantee is based on the factor utilization approach.
		56
		57	Exceptions raised:
		58	XUNVALID_GUEST
		59	This level doesn't support guests. When a guest operation
		60	is called, the exception is raised.
		61
		62	These exceptions are pclass-dependent...
		63	XDEADLINE_MISS
		64	If a task miss his deadline, the exception is raised.
		65	Normally, a CBS task can't cause the raise of such exception because
		66	if it really use more time than declared the deadline is postponed.
		67
		68	Restrictions & special features:
		69	- This level doesn't manage the main task.
		70	- At init time we have to specify:
		71	. guarantee check
		72	(when all task are created the system will check that the task_set
		73	will not use more than the available bandwidth)
		74	- A function to return the used bandwidth of the level is provided.
		75	- A function to return the pending activations of the task.
		76
		77	**/
		78
		79	/*
		80	* Copyright (C) 2000 Paolo Gai
		81	*
		82	* This program is free software; you can redistribute it and/or modify
		83	* it under the terms of the GNU General Public License as published by
		84	* the Free Software Foundation; either version 2 of the License, or
		85	* (at your option) any later version.
		86	*
		87	* This program is distributed in the hope that it will be useful,
		88	* but WITHOUT ANY WARRANTY; without even the implied warranty of
		89	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		90	* GNU General Public License for more details.
		91	*
		92	* You should have received a copy of the GNU General Public License
		93	* along with this program; if not, write to the Free Software
		94	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
		95	*
		96	*/
		97
		98
		99	#ifndef __CBS_H__
		100	#define __CBS_H__
		101
		102	#include <ll/ll.h>
		103	#include <kernel/config.h>
		104	#include <sys/types.h>
		105	#include <kernel/types.h>
80	pj	106	#include "ll/sys/cdefs.h"
2	pj	107
80	pj	108	__BEGIN_DECLS
		109
2	pj	110	/+ flags... +/
		111	#define CBS_DISABLE_ALL 0 /+ Task Guarantee enabled +/
		112	#define CBS_ENABLE_GUARANTEE 1 /+ Task Guarantee enabled +/
		113	#define CBS_ENABLE_ALL 1
		114
		115	#define CBS_FAILED_GUARANTEE 8 /*+ used in the module, unsettable
		116	in EDF_register_level... +*/
		117
		118	/*+ Registration function:
		119	int flags Options to be used in this level instance...
		120	LEVEL master the level that must be used as master level for the
		121	CBS tasks
38	pj	122
		123	returns the level number at which the module has been registered.
2	pj	124	+*/
38	pj	125	LEVEL CBS_register_level(int flags, LEVEL master);
2	pj	126
		127	/+ Returns the used bandwidth of a level +/
		128	bandwidth_t CBS_usedbandwidth(LEVEL l);
		129
		130	/*+ Returns the number of pending activations of a task.
		131	No control is done if the task is not a CBS task! +*/
		132	int CBS_get_nact(LEVEL l, PID p);
		133
80	pj	134	__END_DECLS
2	pj	135	#endif

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