[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 <stdio.h> |
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| 25 | #include <stdlib.h> |
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[596] | 26 | #include <unistd.h> |
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[417] | 27 | #include <pthread.h> |
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[445] | 28 | #include <almosmkh.h> |
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[459] | 29 | #include <hal_macros.h> |
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[417] | 30 | |
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[588] | 31 | #define ARRAY_LENGTH 0x1000 // 4096 values |
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[417] | 32 | |
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[588] | 33 | #define MAX_THREADS 1024 // 16 * 16 * 4 |
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[440] | 34 | |
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| 35 | #define DISPLAY_ARRAY 0 |
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[457] | 36 | #define INTERACTIVE_MODE 0 |
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[440] | 37 | |
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[417] | 38 | ///////////////////////////////////////////////////////////// |
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| 39 | // argument for the sort() function (one thread per core) |
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| 40 | ///////////////////////////////////////////////////////////// |
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| 41 | |
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| 42 | typedef struct |
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| 43 | { |
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| 44 | unsigned int threads; // total number of threads |
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| 45 | unsigned int thread_uid; // thread user index (0 to threads -1) |
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| 46 | unsigned int main_uid; // main thread user index |
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| 47 | } |
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| 48 | args_t; |
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| 49 | |
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| 50 | ////////////////////////////////////////// |
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| 51 | // Global variables |
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| 52 | ////////////////////////////////////////// |
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| 53 | |
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| 54 | int array0[ARRAY_LENGTH]; // values to sort |
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| 55 | int array1[ARRAY_LENGTH]; |
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| 56 | |
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| 57 | pthread_barrier_t barrier; // synchronisation variables |
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| 58 | |
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[440] | 59 | pthread_attr_t attr[MAX_THREADS]; // thread attributes (one per thread) |
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| 60 | args_t arg[MAX_THREADS]; // sort function arguments (one per thread) |
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[417] | 61 | |
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| 62 | //////////////////////////////////// |
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[588] | 63 | static void bubbleSort( int * array, |
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| 64 | unsigned int length, |
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| 65 | unsigned int init_pos ) |
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[417] | 66 | { |
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[473] | 67 | unsigned int i; |
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| 68 | unsigned int j; |
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| 69 | int aux; |
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[417] | 70 | |
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| 71 | for(i = 0; i < length; i++) |
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| 72 | { |
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| 73 | for(j = init_pos; j < (init_pos + length - i - 1); j++) |
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| 74 | { |
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| 75 | if(array[j] > array[j + 1]) |
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| 76 | { |
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| 77 | aux = array[j + 1]; |
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| 78 | array[j + 1] = array[j]; |
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| 79 | array[j] = aux; |
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| 80 | } |
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| 81 | } |
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| 82 | } |
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| 83 | } // end bubbleSort() |
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| 84 | |
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| 85 | |
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[588] | 86 | /////////////////////////////////// |
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| 87 | static void merge( const int * src, |
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| 88 | int * dst, |
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| 89 | int length, |
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| 90 | int init_pos_src_a, |
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| 91 | int init_pos_src_b, |
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| 92 | int init_pos_dst ) |
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[417] | 93 | { |
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| 94 | int i; |
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| 95 | int j; |
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| 96 | int k; |
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| 97 | |
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| 98 | i = 0; |
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| 99 | j = 0; |
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| 100 | k = init_pos_dst; |
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| 101 | |
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| 102 | while((i < length) || (j < length)) |
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| 103 | { |
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| 104 | if((i < length) && (j < length)) |
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| 105 | { |
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| 106 | if(src[init_pos_src_a + i] < src[init_pos_src_b + j]) |
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| 107 | { |
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| 108 | dst[k++] = src[init_pos_src_a + i]; |
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| 109 | i++; |
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| 110 | } |
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| 111 | else |
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| 112 | { |
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| 113 | dst[k++] = src[init_pos_src_b + j]; |
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| 114 | j++; |
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| 115 | } |
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| 116 | } |
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| 117 | else if(i < length) |
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| 118 | { |
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| 119 | dst[k++] = src[init_pos_src_a + i]; |
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| 120 | i++; |
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| 121 | } |
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| 122 | else |
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| 123 | { |
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| 124 | dst[k++] = src[init_pos_src_b + j]; |
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| 125 | j++; |
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| 126 | } |
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| 127 | } |
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| 128 | } // end merge() |
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| 129 | |
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[588] | 130 | ////////////////////////////////////// |
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[504] | 131 | static void sort( const args_t * ptr ) |
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[417] | 132 | { |
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| 133 | unsigned int i; |
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| 134 | unsigned long long cycle; |
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[440] | 135 | unsigned int cxy; |
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| 136 | unsigned int lid; |
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[417] | 137 | |
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| 138 | int * src_array = NULL; |
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| 139 | int * dst_array = NULL; |
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| 140 | |
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[440] | 141 | // get core coordinates an date |
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| 142 | get_core( &cxy , &lid ); |
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| 143 | get_cycle( &cycle ); |
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| 144 | |
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[417] | 145 | unsigned int thread_uid = ptr->thread_uid; |
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| 146 | unsigned int threads = ptr->threads; |
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| 147 | unsigned int main_uid = ptr->main_uid; |
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| 148 | |
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| 149 | unsigned int items = ARRAY_LENGTH / threads; |
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| 150 | unsigned int stages = __builtin_ctz( threads ) + 1; |
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| 151 | |
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[442] | 152 | printf("\n[SORT] thread[%d] : start\n", thread_uid ); |
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| 153 | |
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[417] | 154 | bubbleSort( array0, items, items * thread_uid ); |
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| 155 | |
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[445] | 156 | printf("\n[SORT] thread[%d] : stage 0 completed\n", thread_uid ); |
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[417] | 157 | |
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| 158 | ///////////////////////////////// |
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| 159 | pthread_barrier_wait( &barrier ); |
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[596] | 160 | printf("\n[SORT] thread[%d] exit barrier 0\n", thread_uid ); |
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[440] | 161 | |
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[417] | 162 | // the number of threads contributing to sort |
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| 163 | // is divided by 2 at each next stage |
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| 164 | for ( i = 1 ; i < stages ; i++ ) |
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| 165 | { |
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| 166 | pthread_barrier_wait( &barrier ); |
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| 167 | |
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| 168 | if( (thread_uid & ((1<<i)-1)) == 0 ) |
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| 169 | { |
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[445] | 170 | printf("\n[SORT] thread[%d] : stage %d start\n", thread_uid , i ); |
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[417] | 171 | |
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| 172 | if((i % 2) == 1) // odd stage |
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| 173 | { |
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| 174 | src_array = array0; |
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| 175 | dst_array = array1; |
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| 176 | } |
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| 177 | else // even stage |
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| 178 | { |
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| 179 | src_array = array1; |
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| 180 | dst_array = array0; |
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| 181 | } |
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| 182 | |
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| 183 | merge( src_array, |
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| 184 | dst_array, |
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| 185 | items << i, |
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| 186 | items * thread_uid, |
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| 187 | items * (thread_uid + (1 << (i-1))), |
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| 188 | items * thread_uid ); |
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| 189 | |
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[445] | 190 | printf("\n[SORT] thread[%d] : stage %d completed\n", thread_uid , i ); |
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[417] | 191 | } |
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| 192 | |
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| 193 | ///////////////////////////////// |
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| 194 | pthread_barrier_wait( &barrier ); |
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[596] | 195 | printf("\n[SORT] thread[%d] exit barrier %d\n", thread_uid , i ); |
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[417] | 196 | |
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| 197 | } |
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| 198 | |
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| 199 | // all threads but the main thread exit |
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| 200 | if( thread_uid != main_uid ) pthread_exit( NULL ); |
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| 201 | |
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| 202 | } // end sort() |
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| 203 | |
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| 204 | |
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[574] | 205 | ///////////////// |
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[475] | 206 | void main( void ) |
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[417] | 207 | { |
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| 208 | unsigned int x_size; // number of rows |
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| 209 | unsigned int y_size; // number of columns |
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| 210 | unsigned int ncores; // number of cores per cluster |
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| 211 | unsigned int threads; // total number of threads |
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| 212 | unsigned int thread_uid; // user defined thread index |
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| 213 | unsigned int main_cxy; // cluster identifier for main |
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| 214 | unsigned int main_x; // X coordinate for main thread |
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| 215 | unsigned int main_y; // Y coordinate for main thread |
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| 216 | unsigned int main_lid; // core local index for main thread |
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| 217 | unsigned int main_uid; // thread user index for main thread |
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| 218 | unsigned int x; // X coordinate for a thread |
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| 219 | unsigned int y; // Y coordinate for a thread |
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| 220 | unsigned int lid; // core local index for a thread |
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| 221 | unsigned int n; // index in array to sort |
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| 222 | unsigned long long cycle; // current date for log |
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| 223 | pthread_t trdid; // kernel allocated thread index (unused) |
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| 224 | pthread_barrierattr_t barrier_attr; // barrier attributes |
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| 225 | |
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[596] | 226 | // compute number of threads (one thread per core) |
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[417] | 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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[459] | 232 | main_x = HAL_X_FROM_CXY( main_cxy ); |
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| 233 | main_y = HAL_Y_FROM_CXY( main_cxy ); |
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[417] | 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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[434] | 243 | exit( 0 ); |
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[417] | 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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[434] | 250 | exit( 0 ); |
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[417] | 251 | } |
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| 252 | |
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[588] | 253 | printf("\n[SORT] main starts on core[%x,%d] / %d thread(s) / %d values / PID %x\n", |
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| 254 | main_cxy, main_lid, threads, ARRAY_LENGTH, getpid() ); |
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[417] | 255 | |
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| 256 | // Barrier initialization |
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| 257 | barrier_attr.x_size = x_size; |
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| 258 | barrier_attr.y_size = y_size; |
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| 259 | barrier_attr.nthreads = ncores; |
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| 260 | if( pthread_barrier_init( &barrier, &barrier_attr , threads ) ) |
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| 261 | { |
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| 262 | printf("\n[SORT ERROR] cannot initialise barrier\n" ); |
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[434] | 263 | exit( 0 ); |
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[417] | 264 | } |
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| 265 | |
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[473] | 266 | printf("\n[SORT] main completes barrier init\n"); |
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[417] | 267 | |
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| 268 | // Array to sort initialization |
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| 269 | for ( n = 0 ; n < ARRAY_LENGTH ; n++ ) |
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| 270 | { |
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[596] | 271 | array0[n] = ARRAY_LENGTH - n - 1; |
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[417] | 272 | } |
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| 273 | |
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[440] | 274 | #if DISPLAY_ARRAY |
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[417] | 275 | printf("\n*** array before sort\n"); |
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| 276 | for( n=0; n<ARRAY_LENGTH; n++) printf("array[%d] = %d\n", n , array0[n] ); |
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| 277 | #endif |
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| 278 | |
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[473] | 279 | printf("\n[SORT] main completes array init\n"); |
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[417] | 280 | |
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| 281 | // launch other threads to execute sort() function |
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| 282 | // on cores other than the core running the main thread |
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| 283 | for ( x=0 ; x<x_size ; x++ ) |
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| 284 | { |
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| 285 | for ( y=0 ; y<y_size ; y++ ) |
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| 286 | { |
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| 287 | for ( lid=0 ; lid<ncores ; lid++ ) |
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| 288 | { |
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| 289 | thread_uid = (((x * y_size) + y) * ncores) + lid; |
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| 290 | |
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| 291 | // set sort arguments for all threads |
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| 292 | arg[thread_uid].threads = threads; |
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| 293 | arg[thread_uid].thread_uid = thread_uid; |
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| 294 | arg[thread_uid].main_uid = main_uid; |
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| 295 | |
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| 296 | // set thread attributes for all threads |
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[574] | 297 | attr[thread_uid].attributes = PT_ATTR_DETACH | |
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| 298 | PT_ATTR_CLUSTER_DEFINED | |
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| 299 | PT_ATTR_CORE_DEFINED; |
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[459] | 300 | attr[thread_uid].cxy = HAL_CXY_FROM_XY( x , y ); |
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[417] | 301 | attr[thread_uid].lid = lid; |
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| 302 | |
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| 303 | if( thread_uid != main_uid ) |
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| 304 | { |
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| 305 | if ( pthread_create( &trdid, // not used because no join |
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| 306 | &attr[thread_uid], // thread attributes |
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| 307 | &sort, // entry function |
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| 308 | &arg[thread_uid] ) ) // sort arguments |
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| 309 | { |
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[442] | 310 | printf("\n[SORT ERROR] main cannot create thread %x \n", thread_uid ); |
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[434] | 311 | exit( 0 ); |
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[417] | 312 | } |
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[442] | 313 | else |
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| 314 | { |
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| 315 | printf("\n[SORT] main created thread %x \n", thread_uid ); |
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| 316 | } |
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[440] | 317 | } |
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[417] | 318 | } |
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| 319 | } |
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| 320 | } |
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[442] | 321 | |
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[417] | 322 | get_cycle( &cycle ); |
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[440] | 323 | printf("\n[SORT] main completes threads create at cycle %d\n", (unsigned int)cycle ); |
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[417] | 324 | |
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[442] | 325 | #if INTERACTIVE_MODE |
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| 326 | idbg(); |
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| 327 | #endif |
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[441] | 328 | |
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[445] | 329 | // the main thread run also the sort() function |
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| 330 | sort( &arg[main_uid] ); |
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| 331 | |
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[417] | 332 | // Check result |
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| 333 | int success = 1; |
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| 334 | int* res_array = ( (threads== 2) || |
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| 335 | (threads== 8) || |
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| 336 | (threads== 32) || |
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| 337 | (threads==128) || |
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| 338 | (threads==512) ) ? array1 : array0; |
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| 339 | |
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[441] | 340 | for( n=0 ; n<(ARRAY_LENGTH-2) ; n++ ) |
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[417] | 341 | { |
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| 342 | if ( res_array[n] > res_array[n+1] ) |
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| 343 | { |
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[440] | 344 | printf("\n[SORT] array[%d] = %d > array[%d] = %d\n", |
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| 345 | n , res_array[n] , n+1 , res_array[n+1] ); |
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[417] | 346 | success = 0; |
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| 347 | break; |
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| 348 | } |
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| 349 | } |
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| 350 | |
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[440] | 351 | #if DISPLAY_ARRAY |
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[417] | 352 | printf("\n*** array after sort\n"); |
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| 353 | for( n=0; n<ARRAY_LENGTH; n++) printf("array[%d] = %d\n", n , res_array[n] ); |
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| 354 | #endif |
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| 355 | |
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| 356 | get_cycle( &cycle ); |
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| 357 | |
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| 358 | if ( success ) |
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| 359 | { |
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| 360 | printf("\n[SORT] success at cycle %d\n", (unsigned int)cycle ); |
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[434] | 361 | exit( 0 ); |
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[417] | 362 | } |
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| 363 | else |
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| 364 | { |
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| 365 | printf("\n[SORT] failure at cycle %d\n", (unsigned int)cycle ); |
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[436] | 366 | exit( 1 ); |
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[417] | 367 | } |
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| 368 | |
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| 369 | } // end main() |
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| 370 | |
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| 371 | |
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| 372 | /* |
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| 373 | vim: tabstop=4 : shiftwidth=4 : expandtab |
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| 374 | */ |
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