Scenario:
There are 3 processors/parties: A B C involving. Their pseudocodes are shown as
following.
=================================================
A psuedocode:
...
//send message M1 to C with Isend
MPI_Isend(&M1, sizeof(M1), MPI_BYTE, C,
M1TAG, MPI_COMM_WORLD, &request);
MPI_Wait(&request, &status);
... other computation and communication ....
//send message M2 to B with Isend
MPI_Isend(&M2, sizeof(M2), MPI_BYTE, B,
M2TAG, MPI_COMM_WORLD, &request);
MPI_Wait(&request, &status);
... other computation and communication ....
=================================================
B psuedocode:
...
//receve message M2 from A
MPI_Recv(&M2, sizeof(M2), MPI_BYTE, A,
M2TAG, MPI_COMM_WORLD, &status);
//forward M2 to C
MPI_Isend(&M2, sizeof(M2), MPI_BYTE, C,
M2TAG, MPI_COMM_WORLD, &request);
MPI_Wait(&request, &status);
... other computation and communication ....
=================================================
C psuedocode:
...
MPI_Iprobe(MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &rc,
&status);
switch(status.MPI_TAG)
{
case M1TAG:
recvM1();break;
case M2TAG:
recvM2();break;
...cases for other messages....
}
...
=================================================
Question 1: is it possible that, in party C, M2 is received before M1?
Question 2: After MPI_Isend/MPI_Wait returns, where is the message?
Is the message in the receiving queue on the receiver side?
Question 3: How MPI_Iprobe select a message if MPI_ANY_SOURCE/MPI_ANY_TAG are
used?
Thank you
Hua
-------------------------------------------------
This mail sent through IMP: http://horde.org/imp/
|
