On Nov 10, 2011, at 8:11 AM, Mudassar Majeed wrote: > Thank you for your reply. I am implementing a load balancing function for > MPI, that will balance the computation load and the communication both at a > time. So my algorithm assumes that all the cores may at the end get different > number of processes to run.
Are you talking about over-subscribing cores? I.e., putting more than 1 MPI process on each core? In general, that's not a good idea. > In the beginning (before that function will be called), each core will have > equal number of processes. So I am thinking either to start more processes on > each core (than needed) and run my function for load balancing and then block > the remaining processes (on each core). In this way I will be able to achieve > different number of processes per core. Open MPI spins aggressively looking for network progress. For example, if you block in an MPI_RECV waiting for a message, Open MPI is actively banging on the CPU looking for network progress. Because of this (and other reasons), you probably do not want to over-subscribe your processors (meaning: you probably don't want to put more than 1 process per core). -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
