Hi:
I am testing the performance of an MPI program now. In it, MPI_Isend is used
to send messages of size 4-10K bytes. At the receiver side, MPI_Iprobe is
used to probe incoming messages. When there is a new message arrival,
MPI_Recv is used to receive the message. So basically, it's busy waiting. I
plotted out the delay from the time an MPI_Isend is posted to that when the
message is completely received at the receiver side. The interconnection
network is a 100Mbps fast ethernet.
I found most of the messages are received within 2 ms. From the literature,
this value is reasonable for such type of network. However, occassionally, I
observed some messages suffer 200 ms delay, which is much larger than the
others. My hunch is that network contention caused this problem but am not
quite sure of the real reason behind it. So I am wondering whether anyone
else has such experience before.
Thanks,
Guanhua
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