Daniel, you can run $ ompi_info --parseable --all | grep _algorithm: | grep enumerator
that will give you the list of supported algo for the collectives, here is a sample output : mca:coll:tuned:param:coll_tuned_allreduce_algorithm:enumerator:value:0:ignore mca:coll:tuned:param:coll_tuned_allreduce_algorithm:enumerator:value:1:basic_linear mca:coll:tuned:param:coll_tuned_allreduce_algorithm:enumerator:value:2:nonoverlapping mca:coll:tuned:param:coll_tuned_allreduce_algorithm:enumerator:value:3:recursive_doubling mca:coll:tuned:param:coll_tuned_allreduce_algorithm:enumerator:value:4:ring mca:coll:tuned:param:coll_tuned_allreduce_algorithm:enumerator:value:5:segmented_ring the decision (which algo is used based on communicator size/message size/...) is made in ompi/mca/coll/tuned/coll_tuned_decision_fixed.c and can be overriden via config file or environment variable i cannot point you to a paper, and hopefully someone else will Cheers, Gilles On 2014/11/18 12:53, Faraj, Daniel A wrote: > I am trying to survey the collective algorithms in Open MPI. > I looked at the src code but could not make out the guts of the communication > algorithms. > There are some open mpi papers but not detailed, where they talk about what > algorithms are using in certain collectives. > Has anybody done this sort of work, or point me to a paper? > > Basically, for a given collective operation, what are: > > a) Communication algorithm being used for a given criteria (i.e. message > size or np) > > b) What is theoretical algorithm cost > > Thanx > > > --------------- > Daniel Faraj > > > > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2014/11/25831.php
