openmp – Page 5 – Tarik Billa

What is the difference between atomic and critical in OpenMP?

December 20, 2022 by Tarik

The effect on g_qCount is the same, but what’s done is different. An OpenMP critical section is completely general – it can surround any arbitrary block of code. You pay for that generality, however, by incurring significant overhead every time a thread enters and exits the critical section (on top of the inherent cost of … Read more

omp parallel vs. omp parallel for

November 29, 2022 by Tarik

These are equivalent. #pragma omp parallel spawns a group of threads, while #pragma omp for divides loop iterations between the spawned threads. You can do both things at once with the fused #pragma omp parallel for directive.