Hello... I'm just in progress of selecting an MPI implementation to be used on a compute server cluster at the University of Munich. Since MPI_THREAD_MULTIPLE is a requirement, I went for OpenMPI.
The setup is a rack of boxes running Linux and connected with gigabit ethernet. However, there is a severe problem: Blocking functions like MPI_Probe() suck all CPU power. But as everybody knows, select(2), poll(2) and recently also epoll(2) were invented to give implementes a possibility to write programs with multiple IO channels without the need for busy waiting. So, I wonder if there is a way to have OpenMPI not make use of busy waiting but rather apply some kernel-level event selection function like the ones mentioned above. Regards, Wolfgang
