for (i = 0; i < NITER; i++) {
MPI_Win_lock(MPI_LOCK_SHARED, rank, 0, win);
MPI_Get_accumulate(&acc_val, 1, MPI_INT, &out_val, 1, MPI_INT,
for (i = 0; i < NITER; i++) {
MPI_Win_lock(MPI_LOCK_SHARED, rank, 0, win);
MPI_Get_accumulate(&acc_val, 1, MPI_INT, &out_val, 1, MPI_INT,