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2 | 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 1.1.1.1 2002-03-29 14:12:51 pj Exp $ |
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25 | |||
26 | File: $File$ |
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27 | Revision: $Revision: 1.1.1.1 $ |
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28 | Last update: $Date: 2002-03-29 14:12:51 $ |
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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 <modules/codes.h> |
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107 | |||
108 | /*+ flags... +*/ |
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109 | #define CBS_DISABLE_ALL 0 /*+ Task Guarantee enabled +*/ |
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110 | #define CBS_ENABLE_GUARANTEE 1 /*+ Task Guarantee enabled +*/ |
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111 | #define CBS_ENABLE_ALL 1 |
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112 | |||
113 | #define CBS_FAILED_GUARANTEE 8 /*+ used in the module, unsettable |
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114 | in EDF_register_level... +*/ |
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115 | |||
116 | /*+ Registration function: |
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117 | int flags Options to be used in this level instance... |
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118 | LEVEL master the level that must be used as master level for the |
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119 | CBS tasks |
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120 | +*/ |
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121 | void CBS_register_level(int flags, LEVEL master); |
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122 | |||
123 | /*+ Returns the used bandwidth of a level +*/ |
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124 | bandwidth_t CBS_usedbandwidth(LEVEL l); |
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125 | |||
126 | /*+ Returns the number of pending activations of a task. |
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127 | No control is done if the task is not a CBS task! +*/ |
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128 | int CBS_get_nact(LEVEL l, PID p); |
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129 | |||
130 | |||
131 | #endif |