Thanks Christoph. I should have looked into the FAQ section on MCA params setting @ : http://www.open-mpi.org/faq/?category=tuning#available-mca-params
Thanks again, -- Siddhartha On 16 December 2013 02:41, Christoph Niethammer <nietham...@hlrs.de> wrote: > Hi Siddhartha, > > MPI_Send/Recv in Open MPI implements both protocols and chooses based on > the message size which one to use. > You can use the mca parameter "btl_sm_eager_limit" to modify the behaviour. > > Here the corresponding info obtained from the ompi_info tool: > > "btl_sm_eager_limit" (current value: <4096>, data source: default value) > Maximum size (in bytes) of "short" messages (must be >= 1) > > Regards > Christoph Niethammer > > -- > > Christoph Niethammer > High Performance Computing Center Stuttgart (HLRS) > Nobelstrasse 19 > 70569 Stuttgart > > Tel: ++49(0)711-685-87203 > email: nietham...@hlrs.de > http://www.hlrs.de/people/niethammer > > > > ----- Ursprüngliche Mail ----- > Von: "Siddhartha Jana" <siddharthajan...@gmail.com> > An: "OpenMPI users mailing list" <us...@open-mpi.org> > Gesendet: Samstag, 14. Dezember 2013 13:44:12 > Betreff: [OMPI users] Configuration for rendezvous and eager protocols: > two-sided comm > > > > Hi > > > In OpenMPI, are MPI_Send, MPI_Recv (and friends) implemented using > rendezvous protocol or eager protocol? > > > If both, is there a way to choose one or the other during runtime or while > building the library? > > > If there is a threshold of the message size that dictates the protocol to > be used, is there a way I can alter that threshold value? > > > If different protocols were used for different versions of the library in > the past, could someone please direct me to the exact version numbers of > the implementations that used one or the other protocol? > > > Thanks a lot, > Siddhartha > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
