Hi, I am trying to do parallelization for a computing intensive problem. I am working on a Linux cluster where each node is a multicore processor. e.g. 2 or 4 quad-core processor per node. I want to reduce latency and improve performance as much as possible. I plan to use multiprocessing and multithreading at the same. Each process run on a distinct node and each process spawn many threads on each node. This is a 2 level parallelism. For multiprocessing, I would like to choose MPI. For multithreading, I have two choices: openMP or boost::thread (pthread). Which one has lower latency and higher performance ? It seems that openMP coding is easier (without touching low level thread managing manually). But, it seems that openMP has higher overhead than boost::thread (pthread). Any help is really appreciated. thanks