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1 //========================================================================== |
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2 // |
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3 // sync3.cxx |
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4 // |
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5 // Sync test 3 -- tests priorities and priority inheritance |
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6 // |
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7 //========================================================================== |
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8 //####COPYRIGHTBEGIN#### |
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9 // |
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10 // ------------------------------------------- |
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11 // The contents of this file are subject to the Cygnus eCos Public License |
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12 // Version 1.0 (the "License"); you may not use this file except in |
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13 // compliance with the License. You may obtain a copy of the License at |
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14 // http://sourceware.cygnus.com/ecos |
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15 // |
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16 // Software distributed under the License is distributed on an "AS IS" |
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17 // basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the |
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18 // License for the specific language governing rights and limitations under |
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19 // the License. |
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20 // |
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21 // The Original Code is eCos - Embedded Cygnus Operating System, released |
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22 // September 30, 1998. |
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23 // |
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24 // The Initial Developer of the Original Code is Cygnus. Portions created |
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25 // by Cygnus are Copyright (C) 1998,1999 Cygnus Solutions. All Rights Reserved. |
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26 // ------------------------------------------- |
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27 // |
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28 //####COPYRIGHTEND#### |
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29 //========================================================================== |
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30 //#####DESCRIPTIONBEGIN#### |
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31 // |
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32 // Author(s): dsm |
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33 // Contributors: dsm |
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34 // Date: 1998-02-18 |
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35 // Description: |
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36 // Creates mutexes and threads to set up starvation condition. |
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37 // Checks simple priority inheritance cures this. |
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38 // |
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39 // The starvation condition is caused by the highest priority |
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40 // thread, t0 waiting on a mutex which is never released because |
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41 // it is held by t2. t2 never releases it because t1 will be |
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42 // running at a priority level higher than t2 (but lower than t0). |
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43 // |
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44 // With priority inheritance enabled, t2 will inherit its priority |
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45 // from t0 when t0 tries to grab the mutex. |
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46 // |
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47 // Options: |
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48 // CYGIMP_THREAD_PRIORITY |
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49 // CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INHERITANCE |
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50 // CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INHERITANCE_SIMPLE |
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51 //####DESCRIPTIONEND#### |
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52 |
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53 #include <pkgconf/kernel.h> |
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54 |
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55 #include <cyg/kernel/thread.hxx> |
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56 #include <cyg/kernel/thread.inl> |
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57 #include <cyg/kernel/sched.hxx> |
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58 #include <cyg/kernel/mutex.hxx> |
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59 #include <cyg/kernel/sema.hxx> |
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60 |
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61 #include <cyg/infra/testcase.h> |
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62 |
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63 #include <cyg/kernel/sched.inl> |
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64 |
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65 #ifndef CYGIMP_THREAD_PRIORITY |
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66 #error "Thread priorities disabled" |
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67 #endif |
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68 |
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69 #define NTHREADS 3 |
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70 |
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71 #include "testaux.hxx" |
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72 |
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73 static Cyg_Mutex m0; |
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74 static Cyg_Binary_Semaphore s0, s1, s2; |
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75 |
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76 static cyg_ucount8 m0d = 9; |
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77 |
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78 static void check_priorities_normal() |
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79 { |
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80 CHECK( 5 == thread[0]->get_priority()); |
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81 CHECK( 6 == thread[1]->get_priority()); |
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82 CHECK( 7 == thread[2]->get_priority()); |
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83 } |
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84 |
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85 static void check_priorities_inherited() |
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86 { |
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87 CHECK( 5 == thread[0]->get_priority()); |
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88 CHECK( 6 == thread[1]->get_priority()); |
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89 #ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INHERITANCE |
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90 CHECK( 5 == thread[2]->get_current_priority()); |
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91 #endif |
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92 CHECK( 7 == thread[2]->get_priority()); |
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93 |
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94 } |
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95 |
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96 static void entry0( CYG_ADDRWORD data ) |
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97 { |
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98 s0.wait(); // wait until t2 has gained m0.lock |
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99 check_priorities_normal(); |
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100 m0.lock(); { |
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101 check_priorities_normal(); |
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102 CHECK( 2 == m0d ); |
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103 m0d = 0; |
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104 } m0.unlock(); |
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105 check_priorities_normal(); |
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106 #ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INHERITANCE |
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107 CYG_TEST_PASS_FINISH("Sync 3 OK -- priority inheritance worked"); |
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108 #else |
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109 CYG_TEST_FAIL_FINISH("Sync 3: thread not starved"); |
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110 #endif |
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111 // NOT REACHED |
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112 } |
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113 |
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114 static void entry1( CYG_ADDRWORD data ) |
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115 { |
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116 s1.wait(); |
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117 // The delay below will allow testing of the priority inheritance |
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118 // mechanism when scheduler does not guarantee to schedule threads |
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119 // in strict priority order. |
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120 for ( volatile cyg_ucount32 i=0; i < 100000; i++ ) |
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121 ; // math is hard |
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122 |
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123 #ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INHERITANCE |
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124 // thread0 should have stopped by this point |
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125 CYG_TEST_FAIL_FINISH("Sync 3: priority inheritance mechanism failed"); |
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126 #else |
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127 // With strict priority scheduling and no priority inheritance |
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128 // this is expected to happen. |
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129 CYG_TEST_PASS_FINISH("Sync 3 OK"); |
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130 #endif |
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131 CYG_TEST_FAIL_FINISH("Not reached"); |
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132 } |
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133 |
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134 void entry2( CYG_ADDRWORD data ) |
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135 { |
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136 m0.lock(); { |
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137 CHECK( 9 == m0d ); |
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138 check_priorities_normal(); |
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139 s0.post(); // Now I have lock on m0, wake t0 then t1 |
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140 check_priorities_inherited(); |
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141 s1.post(); |
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142 check_priorities_inherited(); |
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143 m0d = 2; |
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144 } m0.unlock(); |
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145 check_priorities_normal(); |
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146 m0.lock(); { |
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147 check_priorities_normal(); |
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148 CHECK( 0 == m0d ); |
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149 m0d = 21; |
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150 s2.wait(); // never posted |
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151 } m0.unlock(); |
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152 } |
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153 |
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154 |
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155 |
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156 void sync3_main(void) |
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157 { |
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158 CYG_TEST_INIT(); |
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159 |
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160 new_thread( entry0, 0); |
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161 new_thread( entry1, 1); |
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162 new_thread( entry2, 2); |
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163 |
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164 thread[0]->set_priority(5); |
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165 thread[1]->set_priority(6); |
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166 thread[2]->set_priority(7); |
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167 |
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168 Cyg_Scheduler::start(); |
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169 |
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170 CYG_TEST_FAIL_FINISH("Not reached"); |
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171 } |
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172 |
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173 externC void |
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174 cyg_start( void ) |
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175 { |
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176 sync3_main(); |
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177 } |
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178 |
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179 // EOF sync3.cxx |
