[mvapich-discuss] How to display all MPI traffic for a task?

[Thiago Quirino - NOAA Federal]

Hi, folks.

I am working on a numerical weather prediction model that is built on MPI.
There is a call to MPI_Iprobe in a subroutine that is looking for a message
with a specific tag from a specific host (i.e. neither of "MPI_ANY_SOURCE"
or "MPI_ANY_TAG" were used). MPI_Iprobe is returning "true" when in fact
the querying host should not have received a message. Actually, the
subsequent call to MPI_Recv fails because it expects a payload of 12 bytes
(3 integers), but 20 bytes were received (i.e. "Message truncated" error).

So I am trying to figure out where within the vast and complex code a
potential message with the specific tag and from a specific host is being
sent out, that is, a potential tag collision. I am wondering if there is a
debug flag or runtime variable that can be set for MVAPICH2 that will show
all MPI traffic for a task, for example, "Host 0 MPI_Send to Host 10 with
tag 20673", or something like that so that I can locate the bug.

Thank you abundantly for any tips that you may have.

All the best,
Thiago.


---------------------------------------------------
Thiago Quirino, Ph.D.
NOAA Hurricane Research Division
Numerical Modeling Group
4301 Rickenbacker Cswy.
Miami, FL 33149
P: 305-361-4337
C: 305-409-9587
E: Thiago.Quirino at noaa.gov
http://hwrf.aoml.noaa.gov
"The contents of this message are mine personally and do not necessarily
reflect any position of NOAA, its affiliates, or any branch of the federal
and local government."
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