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| 961 | pj | 1 | /* |
| 2 | * Project: S.Ha.R.K. |
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| 3 | * |
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| 4 | * Coordinators: |
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| 5 | * Giorgio Buttazzo <giorgio@sssup.it> |
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| 6 | * Paolo Gai <pj@gandalf.sssup.it> |
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| 7 | * |
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| 8 | * Authors : |
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| 9 | * Paolo Gai <pj@gandalf.sssup.it> |
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| 10 | * Massimiliano Giorgi <massy@gandalf.sssup.it> |
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| 11 | * Luca Abeni <luca@gandalf.sssup.it> |
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| 12 | * (see the web pages for full authors list) |
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| 13 | * |
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| 14 | * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy) |
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| 15 | * |
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| 16 | * http://www.sssup.it |
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| 17 | * http://retis.sssup.it |
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| 18 | * http://shark.sssup.it |
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| 19 | */ |
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| 20 | |||
| 21 | |||
| 22 | /** |
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| 23 | ------------ |
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| 24 | CVS : $Id: cbs.h,v 1.1 2005-02-25 10:53:02 pj Exp $ |
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| 25 | |||
| 26 | File: $File$ |
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| 27 | Revision: $Revision: 1.1 $ |
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| 28 | Last update: $Date: 2005-02-25 10:53:02 $ |
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| 29 | ------------ |
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| 30 | |||
| 31 | This file contains the aperiodic server CBS (Total Bandwidth Server) |
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| 32 | |||
| 33 | Title: |
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| 34 | CBS (Constant Bandwidth Server) |
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| 35 | |||
| 36 | Task Models Accepted: |
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| 37 | SOFT_TASK_MODEL - Soft Tasks |
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| 38 | wcet field is ignored |
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| 39 | met field must be != 0 |
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| 40 | period field must be != 0 |
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| 41 | periodicity field can be either PERIODIC or APERIODIC |
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| 42 | arrivals field can be either SAVE or SKIP |
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| 43 | |||
| 44 | Description: |
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| 45 | This module schedule his tasks following the CBS scheme. |
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| 46 | (see Luca Abeni and Giorgio Buttazzo, |
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| 47 | "Integrating Multimedia Applications in Hard Real-Time Systems" |
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| 48 | Proceedings of the IEEE Real-Time Systems Symposium, Madrid, Spain, |
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| 49 | December 1998) |
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| 50 | |||
| 51 | The tasks are inserted in an EDF level (or similar) with a JOB_TASK_MODEL, |
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| 52 | and the CBS level expects that the task is scheduled with the absolute |
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| 53 | deadline passed in the model. |
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| 54 | |||
| 55 | The task guarantee is based on the factor utilization approach. |
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| 56 | |||
| 57 | Exceptions raised: |
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| 58 | XUNVALID_GUEST |
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| 59 | This level doesn't support guests. When a guest operation |
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| 60 | is called, the exception is raised. |
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| 61 | |||
| 62 | These exceptions are pclass-dependent... |
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| 63 | XDEADLINE_MISS |
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| 64 | If a task miss his deadline, the exception is raised. |
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| 65 | Normally, a CBS task can't cause the raise of such exception because |
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| 66 | if it really use more time than declared the deadline is postponed. |
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| 67 | |||
| 68 | Restrictions & special features: |
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| 69 | - This level doesn't manage the main task. |
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| 70 | - At init time we have to specify: |
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| 71 | . guarantee check |
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| 72 | (when all task are created the system will check that the task_set |
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| 73 | will not use more than the available bandwidth) |
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| 74 | - A function to return the used bandwidth of the level is provided. |
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| 75 | - A function to return the pending activations of the task. |
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| 76 | |||
| 77 | **/ |
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| 78 | |||
| 79 | /* |
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| 80 | * Copyright (C) 2000 Paolo Gai |
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| 81 | * |
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| 82 | * This program is free software; you can redistribute it and/or modify |
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| 83 | * it under the terms of the GNU General Public License as published by |
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| 84 | * the Free Software Foundation; either version 2 of the License, or |
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| 85 | * (at your option) any later version. |
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| 86 | * |
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| 87 | * This program is distributed in the hope that it will be useful, |
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| 88 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 89 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 90 | * GNU General Public License for more details. |
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| 91 | * |
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| 92 | * You should have received a copy of the GNU General Public License |
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| 93 | * along with this program; if not, write to the Free Software |
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| 94 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 95 | * |
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| 96 | */ |
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| 97 | |||
| 98 | |||
| 99 | #ifndef __CBS_H__ |
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| 100 | #define __CBS_H__ |
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| 101 | |||
| 102 | #include <ll/ll.h> |
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| 103 | #include <kernel/config.h> |
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| 104 | #include <sys/types.h> |
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| 105 | #include <kernel/types.h> |
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| 106 | #include "ll/sys/cdefs.h" |
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| 107 | |||
| 108 | __BEGIN_DECLS |
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| 109 | |||
| 110 | /*+ flags... +*/ |
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| 111 | #define CBS_DISABLE_ALL 0 /*+ Task Guarantee enabled +*/ |
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| 112 | #define CBS_ENABLE_GUARANTEE 1 /*+ Task Guarantee enabled +*/ |
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| 113 | #define CBS_ENABLE_ALL 1 |
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| 114 | |||
| 115 | /*+ Registration function: |
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| 116 | int flags Options to be used in this level instance... |
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| 117 | LEVEL master the level that must be used as master level for the |
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| 118 | CBS tasks |
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| 119 | |||
| 120 | returns the level number at which the module has been registered. |
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| 121 | +*/ |
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| 122 | LEVEL CBS_register_level(int flags, LEVEL master); |
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| 123 | |||
| 124 | /*+ Returns the used bandwidth of a level +*/ |
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| 125 | bandwidth_t CBS_usedbandwidth(LEVEL l); |
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| 126 | |||
| 127 | /*+ Returns the number of pending activations of a task. |
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| 128 | No control is done if the task is not a CBS task! +*/ |
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| 129 | int CBS_get_nact(LEVEL l, PID p); |
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| 130 | |||
| 131 | __END_DECLS |
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| 132 | #endif |