On Jun 28, 2010, at 4:03 AM, amjad ali wrote:
> (1)
> Call this subroutines 1000 times
> =============================
> call MPI_RECV_Init()
> call MPI_Send_Init()
> call MPI_Startall()
> call MPI_Free()
> =============================
>
> (2)
> Call this subroutines 1000 times
> ===========================
> call MPI_RECV_Init()
> call MPI_Send_Init()
> call MPI_Startall()
> ==========================
> call MPI_Free() --------- call it only once at the end.
Neither is better. The idea is to do this:
MPI_Recv_init()
MPI_Send_init()
for (i = 0; i < 1000; ++i) {
MPI_Startall()
/* do whatever */
MPI_Waitall()
}
for (i = 0; i < 1000; ++i) {
MPI_Request_free()
}
So in your inner loop, you just call MPI_Startall() and a corresponding
MPI_Test* / MPI_Wait* call to complete those requests.
The idea is that the MPI_*_init() functions do some one-time setup on the
requests and then you just start and complete those same requests over and over
and over. When you're done, you free them.
--
Jeff Squyres
[email protected]
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