[mpiwg-tools] [mpiwg-p2p] Message matching for tools
hermanns at jara.rwth-aachen.de
Fri Dec 18 04:24:57 CST 2015
> at the moment we don't handle MPI_THREAD_MULTIPLE at all. But we want
> to get there ;-)
> You should vote for endpoints, as this may help you out here,
> particularly if users start mapping endpoints 1:1 w/ threads.
That would certainly ease things for us in these situations.
Unfortunately endpoints force use to adapt other infrastructure in our
> b) Creating a derived datatype on the fly to add tool-level data to
> the original payload may induce a large overhead in practically
> _every_ send & receive operation and perturb the measurement.
> You should evaluate this experimentally. I wrote a simple test
> and measured 1.5 us per call of overhead to create a datatype. That
> is not significant except for very small messages.
Thanks for the pointer. You are right. I should evaluate this further.
1.5us does indeed seem tolerable. I wonder how the influence of the
derived datatype is on overall messaging performance, though.
This is also something I should evaluate in the process.
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email: hermanns at jara.rwth-aachen.de
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