Double Ping Pong Test

• The double ping pong test : (known as COMMS2 in the Parkbench suite)

If (my_rank .EQ. master) Then

T0 = mpi_time()

Do i = 1, NREPT

CALL mpi_sendrecv (A, ilen, MPI_BYTE, nslave, 10,

B, ilen, MPI_BYTE, nslave, 20,

MPI_COMM_WORLD, ierr)

CALL mpi_sendrecv (A, ilen, MPI_BYTE, nslave, 10,

B, ilen, MPI_BYTE, nslave, 20,

MPI_COMM_WORLD, ierr)

End do

T1 = mpi_time()

Tn = (T1-T0)/(NREPT*2)

Else

Do i = 1, NREPT

CALL mpi_sendrecv (A, ilen, MPI_BYTE, master, 20,

B, ilen, MPI_BYTE, master, 10,

MPI_COMM_WORLD, status, ierr)

CALL mpi_sendrecv (A, ilen, MPI_BYTE, master, 20,

B, ilen, MPI_BYTE, master, 10,

MPI_COMM_WORLD, ierr)

End do

Endif

If (my_rank .EQ. master) Then

T0 = mpi_time()

Do i = 1, NREPT

CALL shmem_putmem (B, A, ilen,

nslave)

CALL shmem_barrier_all ()!optional

CALL shmem_getmem (A, B, ilen,

nslave)

CALL shmem_barrier_all ()!optional

End do

T1 = mpi_time()

Tn = (T1-T0)/(NREPT*2)

Else

Do i = 1, NREPT

CALL shmem_putmem (B, A, ilen,

master)

CALL shmem_barrier_all ()!optional

CALL shmem_getmem (A, B, ilen,

master)

CALL shmem_barrier_all ()!optional

End do

Endif

MPI Version

SHMEM Version

Since the send/recv arrays (A & B) are independent no synchronization is

necessary in the shmem example but it simulate the best the MPI behavior.

Previous slide

Next slide

Back to first slide

View graphic version