76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <pthread.h>
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#include <sys/time.h>
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#define ARRAY_SIZE 15000576
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#define NUM_THREADS 8 // Adjust based on your CPU cores
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typedef struct {
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float *a;
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float *b;
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float *c;
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int start;
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int end;
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} ThreadData;
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void *add_arrays(void *arg) {
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ThreadData *data = (ThreadData *)arg;
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for (int i = data->start; i < data->end; i++) {
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data->c[i] = data->a[i] + data->b[i];
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}
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return NULL;
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}
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double get_time() {
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struct timeval tv;
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gettimeofday(&tv, NULL);
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return tv.tv_sec + tv.tv_usec * 1e-6;
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}
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int main() {
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float *a = (float*)malloc(ARRAY_SIZE * sizeof(float));
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float *b = (float*)malloc(ARRAY_SIZE * sizeof(float));
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float *c = (float*)malloc(ARRAY_SIZE * sizeof(float));
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// Initialize arrays
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for (int i = 0; i < ARRAY_SIZE; i++) {
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a[i] = i;
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b[i] = i * 2;
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}
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// Create threads
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pthread_t threads[NUM_THREADS];
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ThreadData thread_data[NUM_THREADS];
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int chunk_size = ARRAY_SIZE / NUM_THREADS;
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double start = get_time();
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for (int t = 0; t < NUM_THREADS; t++) {
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thread_data[t].a = a;
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thread_data[t].b = b;
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thread_data[t].c = c;
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thread_data[t].start = t * chunk_size;
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thread_data[t].end = (t == NUM_THREADS - 1) ? ARRAY_SIZE : (t + 1) * chunk_size;
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pthread_create(&threads[t], NULL, add_arrays, &thread_data[t]);
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}
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// Wait for threads to finish
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for (int t = 0; t < NUM_THREADS; t++) {
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pthread_join(threads[t], NULL);
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}
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double calc_time = get_time() - start;
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printf("Pthreads calculation time: %.6f ms\n", calc_time * 1000);
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// Print a sample of the result
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for (int i = 0; i < 10; i++) {
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printf("c[%d] = %f\n", i, c[i]);
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}
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free(a);
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free(b);
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free(c);
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return 0;
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}
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