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base_mutex.cpp
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57 lines (49 loc) · 1.2 KB
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/*!
* \brief Mutex operation in openmp, including
* critical, atomic, lock.
*/
#include <omp.h>
#include <stdio.h>
int main() {
////////////////////////////////////////
// critical
////////////////////////////////////////
printf("critical: \n");
int sum = 0;
#pragma omp parallel for
for (int i = 0; i < 100000; i++) {
// critical corresponds to any size code block.
#pragma omp critical
{
sum += 1;
}
}
printf("sum = %d.\n", sum);
////////////////////////////////////////
// atomic
////////////////////////////////////////
printf("\natomic: \n");
sum = 0;
#pragma omp parallel for
for (int i = 0; i < 100000; i++) {
// atomic corresponds to a single assignment statement
#pragma omp atomic
sum += 1;
}
printf("sum = %d.\n", sum);
////////////////////////////////////////
// lock -> init / destory , set / unset
////////////////////////////////////////
printf("\nlock: \n");
sum = 0;
static omp_lock_t lock;
omp_init_lock(&lock);
#pragma omp parallel for
for (int i = 0; i < 100000; i++) {
omp_set_lock(&lock);
sum += 1;
omp_unset_lock(&lock);
}
omp_destroy_lock(&lock);
printf("sum = %d.\n", sum);
}