[5472ad41] | 1 | /** |
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| 2 | * @file rtems/score/scheduleredf.h |
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| 3 | * |
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[a1f9934a] | 4 | * @brief Data Related to the Manipulation of Threads for the EDF Scheduler |
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| 5 | * |
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[5472ad41] | 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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[c499856] | 16 | * http://www.rtems.org/license/LICENSE. |
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[5472ad41] | 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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[a15eaaf] | 32 | * @defgroup ScoreSchedulerEDF EDF Scheduler |
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[5472ad41] | 33 | * |
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[a15eaaf] | 34 | * @ingroup ScoreScheduler |
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[5472ad41] | 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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[f39f667a] | 48 | _Scheduler_EDF_Change_priority, /* change priority entry point */ \ |
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[5472ad41] | 49 | _Scheduler_EDF_Allocate, /* allocate entry point */ \ |
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[69aa3349] | 50 | _Scheduler_default_Free, /* free entry point */ \ |
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[5472ad41] | 51 | _Scheduler_EDF_Update, /* update entry point */ \ |
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| 52 | _Scheduler_EDF_Priority_compare, /* compares two priorities */ \ |
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| 53 | _Scheduler_EDF_Release_job, /* new period of task */ \ |
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[a344308] | 54 | _Scheduler_default_Tick, /* tick entry point */ \ |
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[1ccb64e1] | 55 | _Scheduler_default_Start_idle /* start idle entry point */ \ |
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[5472ad41] | 56 | } |
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| 57 | |
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| 58 | /** |
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| 59 | * This is just a most significant bit of Priority_Control type. It |
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| 60 | * distinguishes threads which are deadline driven (priority |
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| 61 | * represented by a lower number than @a SCHEDULER_EDF_PRIO_MSB) from those |
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| 62 | * ones who do not have any deadlines and thus are considered background |
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| 63 | * tasks. |
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| 64 | */ |
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| 65 | #define SCHEDULER_EDF_PRIO_MSB 0x80000000 |
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| 66 | |
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[3891983] | 67 | typedef struct { |
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[e1598a6] | 68 | /** |
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| 69 | * @brief Basic scheduler context. |
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| 70 | */ |
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| 71 | Scheduler_Context Base; |
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| 72 | |
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[3891983] | 73 | /** |
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| 74 | * Top of the ready queue. |
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| 75 | */ |
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| 76 | RBTree_Control Ready; |
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[e1598a6] | 77 | } Scheduler_EDF_Context; |
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[3891983] | 78 | |
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[5472ad41] | 79 | /** |
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| 80 | * @typedef Scheduler_EDF_Queue_state |
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| 81 | * |
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| 82 | * This enumeration distiguishes state of a thread with respect to the |
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| 83 | * ready queue. |
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| 84 | */ |
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| 85 | typedef enum { |
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| 86 | SCHEDULER_EDF_QUEUE_STATE_NOT_PRESENTLY, |
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| 87 | SCHEDULER_EDF_QUEUE_STATE_YES, |
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| 88 | SCHEDULER_EDF_QUEUE_STATE_NEVER_HAS_BEEN |
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| 89 | } Scheduler_EDF_Queue_state; |
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| 90 | |
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| 91 | /** |
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[beab7329] | 92 | * @brief Scheduler node specialization for EDF schedulers. |
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[5472ad41] | 93 | */ |
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| 94 | typedef struct { |
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[beab7329] | 95 | /** |
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| 96 | * @brief Basic scheduler node. |
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| 97 | */ |
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| 98 | Scheduler_Node Base; |
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| 99 | |
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[5472ad41] | 100 | /** |
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| 101 | * Pointer to corresponding Thread Control Block. |
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| 102 | */ |
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| 103 | Thread_Control *thread; |
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| 104 | /** |
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| 105 | * Rbtree node related to this thread. |
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| 106 | */ |
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| 107 | RBTree_Node Node; |
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| 108 | /** |
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| 109 | * State of the thread with respect to ready queue. |
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| 110 | */ |
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| 111 | Scheduler_EDF_Queue_state queue_state; |
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[beab7329] | 112 | } Scheduler_EDF_Node; |
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[5472ad41] | 113 | |
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| 114 | /** |
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[a1f9934a] | 115 | * @brief Initialize EDF scheduler. |
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[5472ad41] | 116 | * |
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| 117 | * This routine initializes the EDF scheduler. |
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| 118 | */ |
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[e1598a6] | 119 | void _Scheduler_EDF_Initialize( const Scheduler_Control *scheduler ); |
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[5472ad41] | 120 | |
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| 121 | /** |
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[a1f9934a] | 122 | * @brief Removes thread from ready queue. |
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[5472ad41] | 123 | * |
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| 124 | * This routine removes @a the_thread from the scheduling decision, |
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| 125 | * that is, removes it from the ready queue. It performs |
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| 126 | * any necessary scheduling operations including the selection of |
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| 127 | * a new heir thread. |
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| 128 | * |
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| 129 | * @param[in] the_thread is the thread to be blocked. |
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| 130 | */ |
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| 131 | void _Scheduler_EDF_Block( |
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[e1598a6] | 132 | const Scheduler_Control *scheduler, |
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| 133 | Thread_Control *the_thread |
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[5472ad41] | 134 | ); |
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| 135 | |
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| 136 | /** |
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[a1f9934a] | 137 | * @brief Sets the heir thread to be the next ready thread |
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| 138 | * in the rbtree ready queue. |
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[5472ad41] | 139 | * |
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| 140 | * This kernel routine sets the heir thread to be the next ready thread |
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| 141 | * in the rbtree ready queue. |
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| 142 | */ |
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[24934e36] | 143 | void _Scheduler_EDF_Schedule( |
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[e1598a6] | 144 | const Scheduler_Control *scheduler, |
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| 145 | Thread_Control *the_thread |
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[24934e36] | 146 | ); |
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[5472ad41] | 147 | |
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| 148 | /** |
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[a1f9934a] | 149 | * @brief Allocates EDF specific information of @a the_thread. |
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[5472ad41] | 150 | * |
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| 151 | * This routine allocates EDF specific information of @a the_thread. |
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| 152 | * |
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| 153 | * @param[in] the_thread is the thread the scheduler is allocating |
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| 154 | * management memory for. |
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| 155 | */ |
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[69aa3349] | 156 | bool _Scheduler_EDF_Allocate( |
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[e1598a6] | 157 | const Scheduler_Control *scheduler, |
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| 158 | Thread_Control *the_thread |
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[5472ad41] | 159 | ); |
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| 160 | |
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| 161 | /** |
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[a1f9934a] | 162 | * @brief Updates position in the ready queue of @a the_thread. |
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[5472ad41] | 163 | * |
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| 164 | * This routine updates position in the ready queue of @a the_thread. |
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| 165 | * |
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| 166 | * @param[in] the_thread will have its scheduler specific information |
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| 167 | * structure updated. |
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| 168 | */ |
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| 169 | void _Scheduler_EDF_Update( |
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[e1598a6] | 170 | const Scheduler_Control *scheduler, |
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| 171 | Thread_Control *the_thread |
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[5472ad41] | 172 | ); |
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| 173 | |
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| 174 | /** |
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[a1f9934a] | 175 | * @brief Adds @a the_thread to the scheduling decision. |
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[5472ad41] | 176 | * |
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| 177 | * This routine adds @a the_thread to the scheduling decision, that is, |
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| 178 | * adds it to the ready queue and updates any appropriate scheduling |
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| 179 | * variables, for example the heir thread. |
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| 180 | * |
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| 181 | * @param[in] the_thread will be unblocked. |
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| 182 | */ |
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| 183 | void _Scheduler_EDF_Unblock( |
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[e1598a6] | 184 | const Scheduler_Control *scheduler, |
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| 185 | Thread_Control *the_thread |
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[5472ad41] | 186 | ); |
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| 187 | |
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[f39f667a] | 188 | void _Scheduler_EDF_Change_priority( |
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| 189 | const Scheduler_Control *scheduler, |
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| 190 | Thread_Control *the_thread, |
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| 191 | Priority_Control new_priority, |
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| 192 | bool prepend_it |
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| 193 | ); |
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| 194 | |
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[5472ad41] | 195 | /** |
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[a1f9934a] | 196 | * @brief invoked when a thread wishes to voluntarily |
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| 197 | * transfer control of the processor to another thread |
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| 198 | * with equal deadline. |
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[5472ad41] | 199 | * |
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| 200 | * This routine is invoked when a thread wishes to voluntarily |
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| 201 | * transfer control of the processor to another thread in the queue with |
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| 202 | * equal deadline. This does not have to happen very often. |
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| 203 | * |
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[6eba7c85] | 204 | * This routine will remove the specified THREAD from the ready queue |
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| 205 | * and place it back. The rbtree ready queue is responsible for FIFO ordering |
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[5472ad41] | 206 | * in such a case. |
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[6eba7c85] | 207 | * |
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[961669d] | 208 | * @param[in,out] thread The yielding thread. |
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[5472ad41] | 209 | */ |
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[24934e36] | 210 | void _Scheduler_EDF_Yield( |
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[e1598a6] | 211 | const Scheduler_Control *scheduler, |
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| 212 | Thread_Control *the_thread |
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[24934e36] | 213 | ); |
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[5472ad41] | 214 | |
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| 215 | /** |
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[a1f9934a] | 216 | * @brief Explicitly compare absolute dedlines (priorities) of threads. |
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[5472ad41] | 217 | * |
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| 218 | * This routine explicitly compares absolute dedlines (priorities) of threads. |
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| 219 | * In case of EDF scheduling time overflow is taken into account. |
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| 220 | * |
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[a1f9934a] | 221 | * @retval >0 for p1 > p2; 0 for p1 == p2; <0 for p1 < p2. |
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[5472ad41] | 222 | */ |
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| 223 | int _Scheduler_EDF_Priority_compare ( |
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| 224 | Priority_Control p1, |
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| 225 | Priority_Control p2 |
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| 226 | ); |
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| 227 | |
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| 228 | /** |
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[a1f9934a] | 229 | * @brief Called when a new job of task is released. |
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[5472ad41] | 230 | * |
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| 231 | * This routine is called when a new job of task is released. |
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| 232 | * It is called only from Rate Monotonic manager in the beginning |
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| 233 | * of new period. |
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| 234 | * |
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| 235 | * @param[in] the_thread is the owner of the job. |
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| 236 | * @param[in] deadline of the new job from now. If equal to 0, |
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| 237 | * the job was cancelled or deleted, thus a running task |
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| 238 | * has to be suspended. |
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| 239 | */ |
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| 240 | void _Scheduler_EDF_Release_job ( |
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[e1598a6] | 241 | const Scheduler_Control *scheduler, |
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| 242 | Thread_Control *the_thread, |
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| 243 | uint32_t deadline |
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[5472ad41] | 244 | ); |
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| 245 | |
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| 246 | #ifdef __cplusplus |
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| 247 | } |
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| 248 | #endif |
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| 249 | |
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| 250 | /**@}*/ |
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| 251 | |
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| 252 | #endif |
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[a15eaaf] | 253 | /* end of include file */ |
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