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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: edf.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 scheduling module EDF (Earliest Deadline First) |
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32 | |||
33 | Title: |
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34 | EDF (Earliest Deadline First) |
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35 | |||
36 | Task Models Accepted: |
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37 | HARD_TASK_MODEL - Hard Tasks (Periodic and Sporadic) |
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38 | wcet field and mit field must be != 0. They are used to set the wcet |
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39 | and period of the tasks. |
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40 | periodicity field can be either PERIODIC or APERIODIC |
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41 | drel field is ignored |
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42 | |||
43 | Guest Models Accepted: |
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44 | JOB_TASK_MODEL - a single guest task activation |
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45 | Identified by an absolute deadline and a period. |
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46 | period field is ignored |
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47 | |||
48 | Description: |
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49 | This module schedule his tasks following the classic EDF scheme. |
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50 | The task guarantee is based on the factor utilization approach. |
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51 | The tasks scheduled are periodic and sporadic. The sporadic tasks |
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52 | are like hard task with periodicity set to APERIODIC; they are guaranteed |
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53 | as a periodic task with period equal to the minimum interarrival time. |
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54 | All the task are put in a queue and the scheduling is based on the |
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55 | deadline value. |
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56 | NO GUARANTEE is performed on guest tasks. The guarantee must be performed |
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57 | by the level that inserts guest tasks in the EDF level. |
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58 | |||
59 | Exceptions raised: |
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60 | XUNVALID_GUEST |
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61 | This level doesn't support guests. When a guest operation |
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62 | is called, the exception is raised. |
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63 | |||
64 | These exceptions are pclass-dependent... |
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65 | XDEADLINE_MISS |
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66 | If a task miss his deadline, the exception is raised. |
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67 | |||
68 | XWCET_VIOLATION |
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69 | If a task doesn't end the current cycle before if consume the wcet, |
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70 | an exception is raised, and the task is put in the EDF_WCET_VIOLATED |
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71 | state. To reactivate it, use EDF_task_activate via task_activate or |
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72 | manage directly the EDF data structure. Note that the exception is not |
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73 | handled properly, an XDEADLINE_MISS exeeption will also be raised at |
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74 | the period end... |
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75 | |||
76 | XACTIVATION |
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77 | If a sporadic task is activated with a rate that is greather than the |
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78 | rate declared in the model, this exception is raised and the task is NOT |
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79 | activated. |
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80 | This exception is also raised if we are trying to activate a periodic task |
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81 | stopped with task_sleep before the deadline in which the task_sleep is |
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82 | called. |
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83 | |||
84 | Restrictions & special features: |
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85 | - This level doesn't manage the main task. |
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86 | - At init time we can choose if the level have to activate |
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87 | . the wcet check |
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88 | (If a task require more time than declared, it is stopped and put in |
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89 | the state EDF_WCET_VIOLATED; a XWCET_VIOLATION exception is raised) |
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90 | . the task guarantee algorithm |
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91 | (when all task are created the system will check that the task_set |
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92 | will not use more than the available bandwidth) |
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93 | - The level use the priority and timespec_priority fields. |
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94 | - A function to return the used bandwidth of a level is provided. |
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95 | - The guest tasks don't provide the guest_endcycle function |
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96 | |||
97 | **/ |
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98 | |||
99 | /* |
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100 | * Copyright (C) 2000 Paolo Gai |
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101 | * |
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102 | * This program is free software; you can redistribute it and/or modify |
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103 | * it under the terms of the GNU General Public License as published by |
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104 | * the Free Software Foundation; either version 2 of the License, or |
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105 | * (at your option) any later version. |
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106 | * |
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107 | * This program is distributed in the hope that it will be useful, |
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108 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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109 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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110 | * GNU General Public License for more details. |
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111 | * |
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112 | * You should have received a copy of the GNU General Public License |
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113 | * along with this program; if not, write to the Free Software |
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114 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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115 | * |
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116 | */ |
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117 | |||
118 | |||
119 | #ifndef __EDF_H__ |
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120 | #define __EDF_H__ |
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121 | |||
122 | #include <ll/ll.h> |
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123 | #include <kernel/config.h> |
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124 | #include <sys/types.h> |
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125 | #include <kernel/types.h> |
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126 | #include <modules/codes.h> |
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127 | |||
128 | |||
129 | /*+ flags... +*/ |
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130 | #define EDF_DISABLE_ALL 0 |
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131 | #define EDF_ENABLE_WCET_CHECK 1 /*+ Wcet check enabled +*/ |
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132 | #define EDF_ENABLE_GUARANTEE 2 /*+ Task Guarantee enabled +*/ |
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133 | #define EDF_ENABLE_ALL 3 /*+ All flags enabled +*/ |
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134 | |||
135 | #define EDF_FAILED_GUARANTEE 8 /*+ used in the module, unsettable |
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136 | in EDF_register_level... +*/ |
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137 | |||
138 | |||
139 | /*+ Registration function: |
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140 | int flag Options to be used in this level instance... +*/ |
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141 | void EDF_register_level(int flag); |
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142 | |||
143 | /*+ Returns the used bandwidth of a level +*/ |
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144 | bandwidth_t EDF_usedbandwidth(LEVEL l); |
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145 | |||
146 | #endif |