1 | /////////////////////////////////////////////////////////////////////////////// |
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2 | // File : sort.c |
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3 | // Date : November 2013 |
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4 | // Author : Cesar Fuguet Tortolero <cesar.fuguet-tortolero@lip6.fr> |
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5 | /////////////////////////////////////////////////////////////////////////////// |
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6 | // This multi-threaded application implement a multi-stage sort application. |
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7 | // The various stages are separated by synchronisation barriers. |
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8 | // There is one thread per physical processors. Computation is organised as |
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9 | // a binary tree: All threads contribute to the first stage of parallel sort |
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10 | // but, the number of participating threads is divided by 2 at each next stage. |
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11 | // Number_of_stages = number of barriers = log2(Number_of_threads) |
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12 | // |
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13 | // Constraints : |
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14 | // - It supports up to 1024 processors and the number of processors |
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15 | // must be a power of 2. |
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16 | // _ The array of values to be sorted (ARRAY_LENGTH) must be power of 2 |
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17 | // larger than the number of processors. |
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18 | // - This application uses a single TTY terminal, shared by all threads, |
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19 | // that is protectted by an user-level SQT lock. |
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20 | /////////////////////////////////////////////////////////////////////////////// |
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21 | |
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22 | #include "stdio.h" |
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23 | #include "mapping_info.h" |
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24 | #include "user_barrier.h" |
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25 | #include "user_lock.h" |
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26 | |
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27 | #define ARRAY_LENGTH 0x400 |
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28 | #define VERBOSE 0 |
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29 | |
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30 | // macro to use a shared TTY |
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31 | #define printf(...); { lock_acquire( &tty_lock ); \ |
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32 | giet_tty_printf(__VA_ARGS__); \ |
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33 | lock_release( &tty_lock ); } |
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34 | |
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35 | // argument for the sort() function |
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36 | typedef struct |
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37 | { |
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38 | unsigned int threads; // number of threads (one per core |
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39 | unsigned int index; // user defined thread index |
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40 | } args_t; |
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41 | |
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42 | ////////////////////////////////////////// |
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43 | // Global variables |
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44 | ////////////////////////////////////////// |
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45 | |
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46 | int array0[ARRAY_LENGTH]; |
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47 | int array1[ARRAY_LENGTH]; |
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48 | |
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49 | giet_barrier_t barrier[10]; |
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50 | |
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51 | user_lock_t tty_lock; |
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52 | |
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53 | |
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54 | //////////////////////////////////// |
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55 | void bubbleSort( int * array, |
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56 | unsigned int length, |
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57 | unsigned int init_pos ) |
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58 | { |
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59 | int i; |
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60 | int j; |
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61 | int aux; |
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62 | |
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63 | for(i = 0; i < length; i++) |
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64 | { |
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65 | for(j = init_pos; j < (init_pos + length - i - 1); j++) |
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66 | { |
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67 | if(array[j] > array[j + 1]) |
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68 | { |
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69 | aux = array[j + 1]; |
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70 | array[j + 1] = array[j]; |
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71 | array[j] = aux; |
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72 | } |
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73 | } |
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74 | } |
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75 | } // end bubbleSort() |
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76 | |
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77 | |
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78 | ///////////////////////// |
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79 | void merge( int * array, |
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80 | int * result, |
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81 | int length, |
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82 | int init_pos_a, |
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83 | int init_pos_b, |
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84 | int init_pos_result ) |
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85 | { |
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86 | int i; |
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87 | int j; |
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88 | int k; |
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89 | |
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90 | i = 0; |
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91 | j = 0; |
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92 | k = init_pos_result; |
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93 | |
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94 | while((i < length) || (j < length)) |
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95 | { |
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96 | if((i < length) && (j < length)) |
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97 | { |
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98 | if(array[init_pos_a + i] < array[init_pos_b + j]) |
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99 | { |
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100 | result[k++] = array[init_pos_a + i]; |
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101 | i++; |
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102 | } |
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103 | else |
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104 | { |
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105 | result[k++] = array[init_pos_b + j]; |
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106 | j++; |
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107 | } |
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108 | } |
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109 | else if(i < length) |
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110 | { |
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111 | result[k++] = array[init_pos_a + i]; |
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112 | i++; |
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113 | } |
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114 | else |
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115 | { |
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116 | result[k++] = array[init_pos_b + j]; |
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117 | j++; |
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118 | } |
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119 | } |
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120 | } // end merge() |
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121 | |
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122 | |
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123 | /////////////////////////////////////////////////////////////////// |
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124 | __attribute__ ((constructor)) void sort( args_t* ptr ) |
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125 | /////////////////////////////////////////////////////////////////// |
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126 | { |
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127 | int * src_array = NULL; |
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128 | int * dst_array = NULL; |
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129 | |
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130 | unsigned int thread_id = ptr->index; |
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131 | unsigned int threads = ptr->threads; |
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132 | unsigned int items = ARRAY_LENGTH / threads; |
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133 | unsigned int stages = __builtin_ctz( threads ); |
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134 | unsigned int i; |
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135 | |
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136 | // all threads contribute to the first stage of parallel sort |
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137 | printf("[SORT] Thread %d / Stage 0: Sorting...\n\r", thread_id ); |
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138 | |
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139 | bubbleSort( array0, items, items * thread_id ); |
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140 | |
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141 | printf("[SORT] Thread %d / Stage 0: Completed\n\r", thread_id); |
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142 | |
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143 | // the number of threads is divided by 2 at each next stage |
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144 | for ( i = 0 ; i < stages ; i++ ) |
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145 | { |
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146 | barrier_wait( &barrier[i] ); |
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147 | |
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148 | if((thread_id % (2 << i)) != 0) giet_pthread_exit("Completed"); |
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149 | |
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150 | printf("[SORT] Thread %d / Stage %d: Sorting...\n\r", thread_id, i+1); |
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151 | |
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152 | if((i % 2) == 0) // even stage |
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153 | { |
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154 | src_array = &array0[0]; |
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155 | dst_array = &array1[0]; |
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156 | } |
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157 | else // odd stage |
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158 | { |
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159 | src_array = &array1[0]; |
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160 | dst_array = &array0[0]; |
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161 | } |
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162 | |
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163 | merge( src_array, |
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164 | dst_array, |
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165 | items << i, |
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166 | items * thread_id, |
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167 | items * (thread_id + (1 << i)), |
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168 | items * thread_id ); |
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169 | |
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170 | printf("[SORT] Thread %d / Stage %d: Completed\n\r", thread_id, i+1); |
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171 | } |
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172 | |
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173 | |
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174 | } // end sort() |
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175 | |
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176 | |
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177 | ////////////////////////////////////////// |
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178 | __attribute__ ((constructor)) void main() |
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179 | ////////////////////////////////////////// |
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180 | { |
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181 | unsigned int x_size; // number of rows |
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182 | unsigned int y_size; // number of columns |
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183 | unsigned int nprocs; // number of procs per cluster |
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184 | unsigned int threads; // total number of threads |
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185 | unsigned int n; // index for loops |
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186 | |
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187 | args_t arg[1024]; // array of arguments for sort() |
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188 | |
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189 | // compute number of threads (one thread per proc) |
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190 | giet_procs_number( &x_size , &y_size , &nprocs ); |
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191 | threads = x_size * y_size * nprocs; |
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192 | |
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193 | // alloc a shared TTY used by all threads |
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194 | giet_tty_alloc(1); |
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195 | lock_init( &tty_lock ); |
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196 | |
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197 | // checks number of threads |
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198 | if ( (threads != 1) && (threads != 2) && (threads != 4) && |
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199 | (threads != 8) && (threads != 16 ) && (threads != 32) && |
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200 | (threads != 64) && (threads != 128) && (threads != 256) && |
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201 | (threads != 512) && (threads != 1024) ) |
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202 | { |
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203 | giet_pthread_exit("[SORT ERROR] : number of cores must be power of 2\n"); |
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204 | } |
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205 | |
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206 | // check array size |
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207 | if ( ARRAY_LENGTH % threads) |
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208 | { |
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209 | giet_pthread_exit("[SORT ERROR] : array size must be multiple of number of cores\n"); |
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210 | } |
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211 | |
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212 | // Barriers initialization (number of participants divided by 2 at each stage) |
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213 | for (n = 0; n < __builtin_ctz( threads ); n++) |
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214 | { |
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215 | barrier_init( &barrier[n], threads >> n ); |
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216 | } |
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217 | |
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218 | // Array to sort initialization |
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219 | for ( n = 0 ; n < ARRAY_LENGTH ; n++ ) |
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220 | { |
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221 | array0[n] = giet_rand(); |
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222 | |
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223 | #if VERBOSE |
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224 | printf("array[%d] = %d\n", n , array0[n] ); |
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225 | #endif |
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226 | |
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227 | } |
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228 | |
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229 | printf("\n[SORT] main completes initialisation at cycle %d / %d threads\n", |
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230 | giet_proctime() , threads ); |
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231 | |
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232 | // launch other threads to run sort() function |
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233 | pthread_t trdid; |
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234 | for ( n = 1 ; n < threads ; n++ ) |
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235 | { |
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236 | arg[n].index = n; |
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237 | arg[n].threads = threads; |
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238 | if ( giet_pthread_create( &trdid, // not used because no join |
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239 | NULL, // no attribute |
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240 | &sort, |
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241 | &arg[n] ) ) // pointer on sort arguments |
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242 | { |
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243 | printf("\n[SORT ERROR] creating thread %d\n", n ); |
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244 | giet_pthread_exit( NULL ); |
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245 | } |
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246 | } |
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247 | |
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248 | // main run also the sort() function |
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249 | arg[0].index = 0; |
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250 | arg[0].threads = threads; |
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251 | sort( &arg[0] ); |
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252 | |
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253 | // Check result |
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254 | int success = 1; |
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255 | int* res_array = ( (threads== 2) || |
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256 | (threads== 8) || |
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257 | (threads== 32) || |
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258 | (threads==128) || |
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259 | (threads==512) ) ? array1 : array0; |
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260 | |
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261 | for( n=0 ; n<(ARRAY_LENGTH-1) ; n++ ) |
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262 | { |
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263 | if ( res_array[n] > res_array[n+1] ) |
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264 | { |
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265 | success = 0; |
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266 | break; |
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267 | } |
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268 | } |
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269 | |
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270 | #if VERBOSE |
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271 | for( n=0; n<ARRAY_LENGTH; n++) |
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272 | { |
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273 | printf("array[%d] = %d\n", n , res_array[n] ); |
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274 | } |
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275 | #endif |
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276 | |
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277 | if ( success ) |
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278 | { |
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279 | printf("[SORT] Main completes at cycle %d : success\n", giet_proctime() ); |
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280 | giet_pthread_exit("Success"); |
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281 | } |
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282 | else |
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283 | { |
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284 | printf("[SORT] Main completes at cycle %d : failure\n", giet_proctime() ); |
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285 | giet_pthread_exit("Failure"); |
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286 | } |
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287 | |
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288 | } // end main() |
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289 | |
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290 | |
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291 | /* vim: tabstop=4 : shiftwidth=4 : expandtab |
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292 | */ |
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