58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/time.h>
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#include <omp.h>
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#define ARRAY_SIZE 15000576 // 100 million items
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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(sizeof(float) * ARRAY_SIZE);
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float *b = (float*)malloc(sizeof(float) * ARRAY_SIZE);
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float *c = (float*)malloc(sizeof(float) * ARRAY_SIZE);
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// Initialize arrays (single-threaded)
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double start = get_time();
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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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double init_time = get_time() - start;
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// Set number of threads
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omp_set_num_threads(8);
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// Perform the calculation (parallelized with OpenMP)
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start = get_time();
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// Try different schedules:
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// #pragma omp parallel for schedule(static) // Let the compiler choose chunk size
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// #pragma omp parallel for schedule(dynamic, 256) // Dynamic scheduling
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#pragma omp parallel for schedule(static, 256) // Smaller chunk size
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for (int i = 0; i < ARRAY_SIZE; i++) {
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c[i] = a[i] + b[i];
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}
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double calc_time = get_time() - start;
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// Print timing results
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printf("Array initialization time: %.3f ms\n", init_time * 1000);
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printf("Calculation time: %.3f ms\n", calc_time * 1000);
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printf("Total time: %.3f ms\n", (init_time + 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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// Clean up
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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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