modules, if its priority is zero (the default value). Reason for that is
+ if there is no other module with a priority > 0, the hierarchical
collective module has a problem anyway, since it has to rely on the coll
modules of the subcommunicators. On the other hand, if its priority is
zero, it won't be chosen anyway, and we can simply save the
allreduce/allgather and comm_split operations which might occur during
hierarchy detection.
+ to improve the startup times until we have the modex thing which we
discussed with Jeff and Tim in Knoxville in place
- adding an mca parameter indicating a symmetric configuration. This can
speed up startup times, since each process can conclude from its data onto
the data of the other processes -> no need for the allreduce operations. Per
default this parameter is set to "no".
This commit was SVN r7932.
2ec5fa5d24