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Subject: [OMPI users] Why is the eager limit set to 12K?
From: Simone Pellegrini (spellegrini_at_[hidden])
Date: 2012-05-07 09:25:52

I have one of those 1M dollar questions I guess, but why the eager limit
threshold for Infiniband is set to 12KB by default in OpenMPI? I would
like to know where this value comes from. I am not wondering whether
this is a good setting for this parameter, but just why this is
considered to be a good trade-off for all Infiniband clusters. What I
would like to know at the end of the story is whether this is an
empirical value or if there are architecture characteristics of IB which
make this value come out of pen and paper work (any pointer would be

thanks in advance for the reply.

Simone P.