1 | /** |
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2 | * @file rtems/score/scheduleredf.h |
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3 | * |
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4 | * @brief Data Related to the Manipulation of Threads for the EDF Scheduler |
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5 | * |
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6 | * This include file contains all the constants and structures associated |
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7 | * with the manipulation of threads for the EDF scheduler. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * Copryight (c) 2011 Petr Benes. |
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12 | * Copyright (C) 2011 On-Line Applications Research Corporation (OAR). |
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13 | * |
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14 | * The license and distribution terms for this file may be |
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15 | * found in the file LICENSE in this distribution or at |
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16 | * http://www.rtems.com/license/LICENSE. |
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17 | */ |
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18 | |
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19 | #ifndef _RTEMS_SCORE_SCHEDULEREDF_H |
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20 | #define _RTEMS_SCORE_SCHEDULEREDF_H |
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21 | |
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22 | #include <rtems/score/priority.h> |
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23 | #include <rtems/score/scheduler.h> |
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24 | #include <rtems/score/schedulerpriority.h> |
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25 | #include <rtems/score/rbtree.h> |
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26 | |
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27 | #ifdef __cplusplus |
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28 | extern "C" { |
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29 | #endif |
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30 | |
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31 | /** |
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32 | * @defgroup ScoreSchedulerEDF EDF Scheduler |
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33 | * |
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34 | * @ingroup ScoreScheduler |
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35 | */ |
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36 | /**@{*/ |
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37 | |
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38 | /** |
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39 | * Entry points for the Earliest Deadline First Scheduler. |
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40 | */ |
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41 | #define SCHEDULER_EDF_ENTRY_POINTS \ |
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42 | { \ |
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43 | _Scheduler_EDF_Initialize, /* initialize entry point */ \ |
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44 | _Scheduler_EDF_Schedule, /* schedule entry point */ \ |
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45 | _Scheduler_EDF_Yield, /* yield entry point */ \ |
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46 | _Scheduler_EDF_Block, /* block entry point */ \ |
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47 | _Scheduler_EDF_Unblock, /* unblock entry point */ \ |
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48 | _Scheduler_EDF_Allocate, /* allocate entry point */ \ |
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49 | _Scheduler_EDF_Free, /* free entry point */ \ |
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50 | _Scheduler_EDF_Update, /* update entry point */ \ |
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51 | _Scheduler_EDF_Enqueue, /* enqueue entry point */ \ |
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52 | _Scheduler_EDF_Enqueue_first, /* enqueue_first entry point */ \ |
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53 | _Scheduler_EDF_Extract, /* extract entry point */ \ |
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54 | _Scheduler_EDF_Priority_compare, /* compares two priorities */ \ |
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55 | _Scheduler_EDF_Release_job, /* new period of task */ \ |
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56 | _Scheduler_priority_Tick, /* tick entry point */ \ |
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57 | _Scheduler_default_Start_idle /* start idle entry point */ \ |
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58 | } |
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59 | |
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60 | /** |
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61 | * This is just a most significant bit of Priority_Control type. It |
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62 | * distinguishes threads which are deadline driven (priority |
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63 | * represented by a lower number than @a SCHEDULER_EDF_PRIO_MSB) from those |
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64 | * ones who do not have any deadlines and thus are considered background |
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65 | * tasks. |
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66 | */ |
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67 | #define SCHEDULER_EDF_PRIO_MSB 0x80000000 |
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68 | |
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69 | /** |
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70 | * @typedef Scheduler_EDF_Queue_state |
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71 | * |
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72 | * This enumeration distiguishes state of a thread with respect to the |
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73 | * ready queue. |
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74 | */ |
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75 | typedef enum { |
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76 | SCHEDULER_EDF_QUEUE_STATE_NOT_PRESENTLY, |
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77 | SCHEDULER_EDF_QUEUE_STATE_YES, |
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78 | SCHEDULER_EDF_QUEUE_STATE_NEVER_HAS_BEEN |
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79 | } Scheduler_EDF_Queue_state; |
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80 | |
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81 | /** |
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82 | * This structure handles EDF specific data of a thread. |
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83 | */ |
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84 | typedef struct { |
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85 | /** |
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86 | * Pointer to corresponding Thread Control Block. |
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87 | */ |
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88 | Thread_Control *thread; |
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89 | /** |
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90 | * Rbtree node related to this thread. |
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91 | */ |
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92 | RBTree_Node Node; |
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93 | /** |
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94 | * State of the thread with respect to ready queue. |
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95 | */ |
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96 | Scheduler_EDF_Queue_state queue_state; |
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97 | } Scheduler_EDF_Per_thread; |
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98 | |
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99 | /** |
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100 | * Top of the ready queue. |
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101 | */ |
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102 | extern RBTree_Control _Scheduler_EDF_Ready_queue; |
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103 | |
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104 | /** |
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105 | * @brief Initialize EDF scheduler. |
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106 | * |
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107 | * This routine initializes the EDF scheduler. |
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108 | */ |
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109 | void _Scheduler_EDF_Initialize( void ); |
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110 | |
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111 | /** |
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112 | * @brief Removes thread from ready queue. |
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113 | * |
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114 | * This routine removes @a the_thread from the scheduling decision, |
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115 | * that is, removes it from the ready queue. It performs |
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116 | * any necessary scheduling operations including the selection of |
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117 | * a new heir thread. |
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118 | * |
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119 | * @param[in] the_thread is the thread to be blocked. |
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120 | */ |
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121 | void _Scheduler_EDF_Block( |
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122 | Thread_Control *the_thread |
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123 | ); |
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124 | |
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125 | /** |
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126 | * @brief Sets the heir thread to be the next ready thread |
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127 | * in the rbtree ready queue. |
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128 | * |
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129 | * This kernel routine sets the heir thread to be the next ready thread |
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130 | * in the rbtree ready queue. |
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131 | */ |
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132 | void _Scheduler_EDF_Schedule( void ); |
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133 | |
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134 | /** |
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135 | * @brief Allocates EDF specific information of @a the_thread. |
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136 | * |
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137 | * This routine allocates EDF specific information of @a the_thread. |
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138 | * |
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139 | * @param[in] the_thread is the thread the scheduler is allocating |
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140 | * management memory for. |
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141 | */ |
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142 | void *_Scheduler_EDF_Allocate( |
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143 | Thread_Control *the_thread |
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144 | ); |
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145 | |
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146 | /** |
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147 | * @brief Frees EDF information of a thread. |
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148 | * |
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149 | * This routine frees the EDF specific information of @a the_thread. |
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150 | * |
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151 | * @param[in] the_thread is the thread whose scheduler specific information |
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152 | * will be deallocated. |
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153 | */ |
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154 | void _Scheduler_EDF_Free( |
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155 | Thread_Control *the_thread |
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156 | ); |
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157 | |
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158 | /** |
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159 | * @brief Updates position in the ready queue of @a the_thread. |
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160 | * |
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161 | * This routine updates position in the ready queue of @a the_thread. |
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162 | * |
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163 | * @param[in] the_thread will have its scheduler specific information |
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164 | * structure updated. |
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165 | */ |
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166 | void _Scheduler_EDF_Update( |
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167 | Thread_Control *the_thread |
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168 | ); |
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169 | |
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170 | /** |
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171 | * @brief Adds @a the_thread to the scheduling decision. |
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172 | * |
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173 | * This routine adds @a the_thread to the scheduling decision, that is, |
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174 | * adds it to the ready queue and updates any appropriate scheduling |
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175 | * variables, for example the heir thread. |
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176 | * |
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177 | * @param[in] the_thread will be unblocked. |
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178 | */ |
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179 | void _Scheduler_EDF_Unblock( |
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180 | Thread_Control *the_thread |
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181 | ); |
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182 | |
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183 | /** |
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184 | * @brief invoked when a thread wishes to voluntarily |
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185 | * transfer control of the processor to another thread |
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186 | * with equal deadline. |
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187 | * |
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188 | * This routine is invoked when a thread wishes to voluntarily |
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189 | * transfer control of the processor to another thread in the queue with |
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190 | * equal deadline. This does not have to happen very often. |
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191 | * |
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192 | * This routine will remove the running THREAD from the ready queue |
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193 | * and place back. The rbtree ready queue is responsible for FIFO ordering |
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194 | * in such a case. |
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195 | */ |
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196 | void _Scheduler_EDF_Yield( void ); |
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197 | |
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198 | /** |
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199 | * @brief Put @a the_thread to the rbtree ready queue. |
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200 | * |
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201 | * This routine puts @a the_thread to the rbtree ready queue. |
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202 | * |
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203 | * @param[in] the_thread will be enqueued to the ready queue. |
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204 | */ |
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205 | void _Scheduler_EDF_Enqueue( |
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206 | Thread_Control *the_thread |
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207 | ); |
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208 | |
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209 | /** |
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210 | * @brief Enqueue a thread to the ready queue. |
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211 | * |
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212 | * This routine puts @a the_thread to the rbtree ready queue. |
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213 | * For the EDF scheduler this is the same as @a _Scheduler_EDF_Enqueue. |
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214 | * |
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215 | * @param[in] the_thread will be enqueued to the ready queue. |
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216 | */ |
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217 | void _Scheduler_EDF_Enqueue_first( |
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218 | Thread_Control *the_thread |
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219 | ); |
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220 | |
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221 | /** |
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222 | * @brief Remove a specific thread from the scheduler's set |
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223 | * of ready threads. |
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224 | * |
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225 | * This routine removes a specific thread from the scheduler's set |
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226 | * of ready threads. |
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227 | * |
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228 | * @param[in] the_thread will be extracted from the ready set. |
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229 | */ |
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230 | void _Scheduler_EDF_Extract( |
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231 | Thread_Control *the_thread |
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232 | ); |
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233 | |
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234 | /** |
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235 | * @brief Explicitly compare absolute dedlines (priorities) of threads. |
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236 | * |
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237 | * This routine explicitly compares absolute dedlines (priorities) of threads. |
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238 | * In case of EDF scheduling time overflow is taken into account. |
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239 | * |
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240 | * @retval >0 for p1 > p2; 0 for p1 == p2; <0 for p1 < p2. |
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241 | */ |
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242 | int _Scheduler_EDF_Priority_compare ( |
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243 | Priority_Control p1, |
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244 | Priority_Control p2 |
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245 | ); |
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246 | |
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247 | /** |
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248 | * @brief Called when a new job of task is released. |
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249 | * |
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250 | * This routine is called when a new job of task is released. |
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251 | * It is called only from Rate Monotonic manager in the beginning |
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252 | * of new period. |
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253 | * |
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254 | * @param[in] the_thread is the owner of the job. |
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255 | * @param[in] deadline of the new job from now. If equal to 0, |
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256 | * the job was cancelled or deleted, thus a running task |
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257 | * has to be suspended. |
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258 | */ |
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259 | void _Scheduler_EDF_Release_job ( |
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260 | Thread_Control *the_thread, |
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261 | uint32_t deadline |
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262 | ); |
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263 | |
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264 | #ifdef __cplusplus |
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265 | } |
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266 | #endif |
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267 | |
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268 | /**@}*/ |
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269 | |
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270 | #endif |
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271 | /* end of include file */ |
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