Jeff Squyres wrote:
On Aug 24, 2009, at 2:18 PM, Shaun Jackman wrote:
I'm seeing MPI_Send block in mca_pml_ob1_send. The packet is shorter
than the eager transmit limit for shared memory (3300 bytes < 4096
bytes). I'm trying to determine if MPI_Send is blocking due to a
deadlock. Will MPI_Send block even when sending a packet eagerly?
It can, yes. Message size is one of multiple factors that can cause
MPI_SEND to block -- so yes, it's even possible for short/eager
messages to block in MPI_SEND.
Can you tell if the corresponding receive has already been posted and
is making progress in the receiver?
Hi Jeff,
The receiver posts a single MPI_Irecv in advance, and as soon as it's
received a message it posts a new MPI_Irecv. However, there are
multiple processes sending to the receiver, and only one MPI_Irecv posted.
Cheers,
Shaun
