I am Roswan Ismail from Malaysia. I am focusing on MPI
communication performance on quad-core cluster at my university. I used Open
MPI-1.4.3 and measurements were done using scampi benchmark.
As I know, open MPI used multiple algorithms to broadcast
data (MPI_BCAST) such as binomial, pipeline, binary tree, basic linear and
split binary tree. All these algorithms will be used based on message size and
communicator size. For example, binomial is used when message size to be
broadcasted is small while pipeline used for broadcasting a large message.
What I want to do now is, to use fixed algorithm i.e
binomial for all message size. I want to see and compare the results with the
default results. So, I was modified coll_tuned_decision_fixed.c which is
located in open mpi-1.4.3/ompi/mca/coll/tuned by returning binomial algorithm
for all condition. Then I recompile the files but the problem is, the results
obtained is same as default. It seems I do not do any changes to the codes.
So could you guys tell me the right way to do that.
Roswan Binti Ismail,
Univ. Pend. Sultan Idris,
Tg Malim, Perak.