Rick,
can you please provide some more information :
- Open MPI version
- interconnect used
- number of tasks / number of nodes
- does the hang occur in the first MPI_Bcast of 8000 bytes ?
note there is a known issue if you MPI_Bcast with different but matching
signatures
(e.g. some tasks MPI_Bcast 8000 MPI_BYTE, while some other tasks
MPI_Bcast 1 vector of 8000 MPI_BYTE)
you might want to try
mpirun --mca coll ^tuned
and see if it helps
Cheers,
Gilles
On 9/30/2016 6:52 AM, Marlborough, Rick wrote:
Folks;
I am attempting to set up a task that sends large
messages via MPI_Bcast api. I am finding that small message work ok,
anything less then 8000 bytes. Anything more than this then the whole
scenario hangs with most of the worker processes pegged at 100% cpu
usage. Tried some of the configuration settings from FAQ page, but
these did not make a difference. Is there anything else I can try??
Thanks
Rick
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