[417] | 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 cores. |
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| 9 | // Computation is organised as a binary tree: |
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| 10 | // - All threads execute in parallel a buble sort on a sub-array during the |
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| 11 | // the first stage of parallel sort, |
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| 12 | // - The number of participating threads is divided by 2 at each next stage, |
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| 13 | // to make a merge sort, on two subsets of previous stage. |
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| 14 | // |
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| 15 | // Number_of_stages = number of barriers = log2(Number_of_threads) |
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| 16 | // |
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| 17 | // Constraints : |
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| 18 | // - It supports up to 1024 cores: x_size, y_size, and ncores must be |
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| 19 | // power of 2 (max 16*16 clusters / max 4 cores per cluster) |
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| 20 | // _ The array of values to be sorted (ARRAY_LENGTH) must be power of 2 |
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| 21 | // larger than the number of cores. |
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| 22 | /////////////////////////////////////////////////////////////////////////////// |
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| 23 | |
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| 24 | #include <nostdio.h> |
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| 25 | #include <stdio.h> |
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| 26 | #include <stdlib.h> |
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| 27 | #include <malloc.h> |
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| 28 | #include <pthread.h> |
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| 29 | |
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| 30 | #define ARRAY_LENGTH 0x100 // 256 values |
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| 31 | #define VERBOSE 0 |
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| 32 | |
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| 33 | /////////////////////////////////////////////////////// |
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| 34 | // macros for fixed format cxy <=> (x,y) translation |
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| 35 | /////////////////////////////////////////////////////// |
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| 36 | |
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| 37 | #define CXY_FROM_XY( x , y ) ((x<<4) + y) |
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| 38 | |
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| 39 | #define X_FROM_CXY( cxy ) ((cxy>>4) & 0xF) |
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| 40 | |
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| 41 | #define Y_FROM_CXY( cxy ) (cxy & 0xF) |
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| 42 | |
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| 43 | ///////////////////////////////////////////////////////////// |
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| 44 | // argument for the sort() function (one thread per core) |
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| 45 | ///////////////////////////////////////////////////////////// |
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| 46 | |
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| 47 | typedef struct |
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| 48 | { |
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| 49 | unsigned int threads; // total number of threads |
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| 50 | unsigned int thread_uid; // thread user index (0 to threads -1) |
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| 51 | unsigned int main_uid; // main thread user index |
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| 52 | } |
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| 53 | args_t; |
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| 54 | |
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| 55 | ////////////////////////////////////////// |
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| 56 | // Global variables |
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| 57 | ////////////////////////////////////////// |
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| 58 | |
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| 59 | int array0[ARRAY_LENGTH]; // values to sort |
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| 60 | int array1[ARRAY_LENGTH]; |
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| 61 | |
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| 62 | pthread_barrier_t barrier; // synchronisation variables |
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| 63 | |
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| 64 | |
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| 65 | //////////////////////////////////// |
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| 66 | void bubbleSort( int * array, |
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| 67 | unsigned int length, |
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| 68 | unsigned int init_pos ) |
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| 69 | { |
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| 70 | int i; |
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| 71 | int j; |
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| 72 | int aux; |
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| 73 | |
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| 74 | for(i = 0; i < length; i++) |
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| 75 | { |
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| 76 | for(j = init_pos; j < (init_pos + length - i - 1); j++) |
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| 77 | { |
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| 78 | if(array[j] > array[j + 1]) |
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| 79 | { |
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| 80 | aux = array[j + 1]; |
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| 81 | array[j + 1] = array[j]; |
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| 82 | array[j] = aux; |
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| 83 | } |
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| 84 | } |
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| 85 | } |
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| 86 | } // end bubbleSort() |
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| 87 | |
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| 88 | |
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| 89 | ///////////////////////// |
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| 90 | void merge( int * src, |
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| 91 | int * dst, |
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| 92 | int length, |
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| 93 | int init_pos_src_a, |
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| 94 | int init_pos_src_b, |
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| 95 | int init_pos_dst ) |
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| 96 | { |
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| 97 | int i; |
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| 98 | int j; |
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| 99 | int k; |
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| 100 | |
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| 101 | i = 0; |
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| 102 | j = 0; |
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| 103 | k = init_pos_dst; |
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| 104 | |
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| 105 | while((i < length) || (j < length)) |
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| 106 | { |
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| 107 | if((i < length) && (j < length)) |
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| 108 | { |
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| 109 | if(src[init_pos_src_a + i] < src[init_pos_src_b + j]) |
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| 110 | { |
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| 111 | dst[k++] = src[init_pos_src_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 | dst[k++] = src[init_pos_src_b + j]; |
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| 117 | j++; |
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| 118 | } |
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| 119 | } |
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| 120 | else if(i < length) |
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| 121 | { |
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| 122 | dst[k++] = src[init_pos_src_a + i]; |
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| 123 | i++; |
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| 124 | } |
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| 125 | else |
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| 126 | { |
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| 127 | dst[k++] = src[init_pos_src_b + j]; |
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| 128 | j++; |
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| 129 | } |
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| 130 | } |
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| 131 | } // end merge() |
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| 132 | |
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| 133 | ///////////////////////// |
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| 134 | void sort( args_t * ptr ) |
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| 135 | { |
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| 136 | unsigned int i; |
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| 137 | unsigned long long cycle; |
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| 138 | |
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| 139 | int * src_array = NULL; |
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| 140 | int * dst_array = NULL; |
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| 141 | |
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| 142 | unsigned int thread_uid = ptr->thread_uid; |
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| 143 | unsigned int threads = ptr->threads; |
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| 144 | unsigned int main_uid = ptr->main_uid; |
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| 145 | |
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| 146 | unsigned int items = ARRAY_LENGTH / threads; |
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| 147 | unsigned int stages = __builtin_ctz( threads ) + 1; |
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| 148 | |
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| 149 | get_cycle( &cycle ); |
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| 150 | printf("\n[SORT] thread[%d] enter at cycle %d\n", thread_uid , (unsigned int)cycle ); |
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| 151 | |
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| 152 | printf("\n[SORT] thread[%d] / stage 0 start\n", thread_uid ); |
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| 153 | |
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| 154 | bubbleSort( array0, items, items * thread_uid ); |
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| 155 | |
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| 156 | printf("\n[SORT] thread[%d] / stage 0 completed\n", thread_uid ); |
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| 157 | |
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| 158 | ///////////////////////////////// |
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| 159 | pthread_barrier_wait( &barrier ); |
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| 160 | |
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| 161 | // the number of threads contributing to sort |
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| 162 | // is divided by 2 at each next stage |
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| 163 | for ( i = 1 ; i < stages ; i++ ) |
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| 164 | { |
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| 165 | pthread_barrier_wait( &barrier ); |
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| 166 | |
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| 167 | if( (thread_uid & ((1<<i)-1)) == 0 ) |
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| 168 | { |
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| 169 | printf("\n[SORT] thread[%d] / stage %d start\n", thread_uid , i ); |
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| 170 | |
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| 171 | if((i % 2) == 1) // odd stage |
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| 172 | { |
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| 173 | src_array = array0; |
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| 174 | dst_array = array1; |
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| 175 | } |
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| 176 | else // even stage |
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| 177 | { |
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| 178 | src_array = array1; |
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| 179 | dst_array = array0; |
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| 180 | } |
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| 181 | |
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| 182 | merge( src_array, |
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| 183 | dst_array, |
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| 184 | items << i, |
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| 185 | items * thread_uid, |
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| 186 | items * (thread_uid + (1 << (i-1))), |
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| 187 | items * thread_uid ); |
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| 188 | |
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| 189 | printf("\n[SORT] thread[%d] / stage %d completed\n", thread_uid , i ); |
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| 190 | } |
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| 191 | |
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| 192 | ///////////////////////////////// |
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| 193 | pthread_barrier_wait( &barrier ); |
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| 194 | |
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| 195 | } |
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| 196 | |
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| 197 | // all threads but the main thread exit |
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| 198 | if( thread_uid != main_uid ) pthread_exit( NULL ); |
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| 199 | |
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| 200 | } // end sort() |
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| 201 | |
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| 202 | |
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| 203 | /////////// |
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| 204 | void main() |
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| 205 | { |
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| 206 | unsigned int x_size; // number of rows |
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| 207 | unsigned int y_size; // number of columns |
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| 208 | unsigned int ncores; // number of cores per cluster |
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| 209 | unsigned int threads; // total number of threads |
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| 210 | unsigned int thread_uid; // user defined thread index |
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| 211 | unsigned int main_cxy; // cluster identifier for main |
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| 212 | unsigned int main_x; // X coordinate for main thread |
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| 213 | unsigned int main_y; // Y coordinate for main thread |
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| 214 | unsigned int main_lid; // core local index for main thread |
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| 215 | unsigned int main_uid; // thread user index for main thread |
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| 216 | unsigned int x; // X coordinate for a thread |
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| 217 | unsigned int y; // Y coordinate for a thread |
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| 218 | unsigned int lid; // core local index for a thread |
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| 219 | unsigned int n; // index in array to sort |
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| 220 | unsigned long long cycle; // current date for log |
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| 221 | pthread_t trdid; // kernel allocated thread index (unused) |
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| 222 | pthread_barrierattr_t barrier_attr; // barrier attributes |
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| 223 | pthread_attr_t attr[1024]; // thread attributes (one per thread) |
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| 224 | args_t arg[1024]; // sort function arguments (one per thread) |
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| 225 | |
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| 226 | // compute number of threads (one thread per proc) |
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| 227 | get_config( &x_size , &y_size , &ncores ); |
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| 228 | threads = x_size * y_size * ncores; |
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| 229 | |
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| 230 | // get core coordinates and user index for the main thread |
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| 231 | get_core( &main_cxy , & main_lid ); |
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| 232 | main_x = X_FROM_CXY( main_cxy ); |
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| 233 | main_y = Y_FROM_CXY( main_cxy ); |
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| 234 | main_uid = (((main_x * y_size) + main_y) * ncores) + main_lid; |
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| 235 | |
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| 236 | // checks number of threads |
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| 237 | if ( (threads != 1) && (threads != 2) && (threads != 4) && |
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| 238 | (threads != 8) && (threads != 16 ) && (threads != 32) && |
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| 239 | (threads != 64) && (threads != 128) && (threads != 256) && |
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| 240 | (threads != 512) && (threads != 1024) ) |
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| 241 | { |
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| 242 | printf("\n[SORT ERROR] number of cores must be power of 2\n"); |
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| 243 | pthread_exit( NULL ); |
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| 244 | } |
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| 245 | |
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| 246 | // check array size |
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| 247 | if ( ARRAY_LENGTH % threads) |
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| 248 | { |
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| 249 | printf("\n[SORT ERROR] array size must be multiple of number of threads\n"); |
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| 250 | pthread_exit( NULL ); |
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| 251 | } |
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| 252 | |
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| 253 | get_cycle( &cycle ); |
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| 254 | printf("\n[SORT] starts : %d threads / %d values / cycle %d\n", |
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| 255 | threads, ARRAY_LENGTH , (unsigned int)cycle ); |
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| 256 | |
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| 257 | // Barrier initialization |
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| 258 | barrier_attr.x_size = x_size; |
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| 259 | barrier_attr.y_size = y_size; |
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| 260 | barrier_attr.nthreads = ncores; |
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| 261 | if( pthread_barrier_init( &barrier, &barrier_attr , threads ) ) |
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| 262 | { |
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| 263 | printf("\n[SORT ERROR] cannot initialise barrier\n" ); |
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| 264 | pthread_exit( NULL ); |
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| 265 | } |
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| 266 | |
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| 267 | get_cycle( &cycle ); |
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| 268 | printf("\n[SORT] completes barrier init at cycle %d\n", (unsigned int)cycle ); |
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| 269 | |
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| 270 | // Array to sort initialization |
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| 271 | for ( n = 0 ; n < ARRAY_LENGTH ; n++ ) |
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| 272 | { |
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| 273 | array0[n] = rand(); |
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| 274 | } |
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| 275 | |
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| 276 | #if VERBOSE |
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| 277 | printf("\n*** array before sort\n"); |
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| 278 | for( n=0; n<ARRAY_LENGTH; n++) printf("array[%d] = %d\n", n , array0[n] ); |
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| 279 | #endif |
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| 280 | |
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| 281 | get_cycle( &cycle ); |
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| 282 | printf("\n[SORT] completes array init at cycle %d\n", (unsigned int)cycle ); |
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| 283 | |
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| 284 | // launch other threads to execute sort() function |
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| 285 | // on cores other than the core running the main thread |
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| 286 | for ( x=0 ; x<x_size ; x++ ) |
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| 287 | { |
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| 288 | for ( y=0 ; y<y_size ; y++ ) |
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| 289 | { |
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| 290 | for ( lid=0 ; lid<ncores ; lid++ ) |
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| 291 | { |
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| 292 | thread_uid = (((x * y_size) + y) * ncores) + lid; |
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| 293 | |
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| 294 | // set sort arguments for all threads |
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| 295 | arg[thread_uid].threads = threads; |
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| 296 | arg[thread_uid].thread_uid = thread_uid; |
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| 297 | arg[thread_uid].main_uid = main_uid; |
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| 298 | |
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| 299 | // set thread attributes for all threads |
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| 300 | attr[thread_uid].attributes = PT_ATTR_CLUSTER_DEFINED | PT_ATTR_CORE_DEFINED; |
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| 301 | attr[thread_uid].cxy = CXY_FROM_XY( x , y ); |
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| 302 | attr[thread_uid].lid = lid; |
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| 303 | |
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| 304 | if( thread_uid != main_uid ) |
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| 305 | { |
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| 306 | if ( pthread_create( &trdid, // not used because no join |
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| 307 | &attr[thread_uid], // thread attributes |
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| 308 | &sort, // entry function |
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| 309 | &arg[thread_uid] ) ) // sort arguments |
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| 310 | { |
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| 311 | printf("\n[SORT ERROR] creating thread %x\n", thread_uid ); |
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| 312 | pthread_exit( NULL ); |
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| 313 | } |
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| 314 | |
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| 315 | } |
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| 316 | } |
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| 317 | } |
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| 318 | } |
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| 319 | |
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| 320 | get_cycle( &cycle ); |
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| 321 | printf("\n[SORT] completes threads create at cycle %d\n", (unsigned int)cycle ); |
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| 322 | |
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| 323 | // main run also the sort() function |
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| 324 | sort( &arg[main_uid] ); |
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| 325 | |
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| 326 | // Check result |
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| 327 | int success = 1; |
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| 328 | int* res_array = ( (threads== 2) || |
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| 329 | (threads== 8) || |
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| 330 | (threads== 32) || |
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| 331 | (threads==128) || |
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| 332 | (threads==512) ) ? array1 : array0; |
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| 333 | |
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| 334 | for( n=0 ; n<(ARRAY_LENGTH-1) ; n++ ) |
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| 335 | { |
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| 336 | if ( res_array[n] > res_array[n+1] ) |
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| 337 | { |
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| 338 | success = 0; |
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| 339 | break; |
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| 340 | } |
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| 341 | } |
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| 342 | |
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| 343 | #if VERBOSE |
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| 344 | printf("\n*** array after sort\n"); |
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| 345 | for( n=0; n<ARRAY_LENGTH; n++) printf("array[%d] = %d\n", n , res_array[n] ); |
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| 346 | #endif |
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| 347 | |
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| 348 | get_cycle( &cycle ); |
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| 349 | |
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| 350 | if ( success ) |
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| 351 | { |
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| 352 | printf("\n[SORT] success at cycle %d\n", (unsigned int)cycle ); |
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| 353 | pthread_exit( NULL ); |
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| 354 | } |
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| 355 | else |
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| 356 | { |
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| 357 | printf("\n[SORT] failure at cycle %d\n", (unsigned int)cycle ); |
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| 358 | pthread_exit( NULL ); |
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| 359 | } |
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| 360 | |
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| 361 | } // end main() |
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| 362 | |
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| 363 | |
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| 364 | /* |
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| 365 | vim: tabstop=4 : shiftwidth=4 : expandtab |
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| 366 | */ |
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