[OMPI users] Algorithms used in MPI_BCast

[Mohammed El Mehdi DIOURI]

Hi, 

I would like to know what are the algorithms used in MPI_BCast() in the OpenMPI 
implementation. 

For example, in MPICH2, depending on the number of processes and the size of 
data to broadcast, the broadcasting algorithm used can be different : a 
binomial tree if the message is short or MPI_Scatter followed by MPI_AllGather 
if the message to broadcast is long.

Is it the same for OpenMPI ? 
It doesn't seem to be the case since the broadcasting time is different when I 
use OpenMPI or MPICH2.

Thanks for your help,

Mehdi.