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Subject: [OMPI users] coll_tuned_decision_fixed.c
From: Andy Georgi (Andy.Georgi_at_[hidden])
Date: 2008-04-24 01:41:35

Dear all,

to explain the behavior of MPI_Reduce on our cluster i ran through the
source of Open MPI 1.2.6. On line 357 i found a mistake (maybe ;-)). It
should be:

return ompi_coll_tuned_reduce_intra_binary(sendbuf, recvbuf, count,
datatype, op, root, comm, segsize);

instead of

return ompi_coll_tuned_reduce_intra_pipeline (sendbuf, recvbuf, count,
datatype, op, root, comm, segsize);

There are 2 indications:
- the next branch is doing the same (32K pipelining)
- the comment /* Binary_32K */ sounds not like "pipeline" ;-)

Maybe someone is interested in.



Dresden University of Technology
Center for Information Services
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Phone:    (+49) 351/463-38783
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e-mail: Andy.Georgi_at_[hidden]