In certain hybrid, heterogeneous HPC configurations, mpirun often cannot or should not be threaded through the OS under which OpenMPI runs. The primary OS and MPI can configure management nodes and topologies (even other MPI layers) that subsequently spawn various OSes and other lightweight kernels. These share memory spaces and indirectly access the program stacks in various devices.
In short, yes, there are environments where this would cause a problem. ================== Kenneth A. Lloyd Watt Systems Technologies Inc. -----Original Message----- From: devel-boun...@open-mpi.org [mailto:devel-boun...@open-mpi.org] On Behalf Of Barrett, Brian W Sent: Tuesday, October 12, 2010 8:24 AM To: Open MPI Developers Subject: Re: [OMPI devel] Threading On Oct 11, 2010, at 11:41 PM, Ralph Castain wrote: > Does anyone know of a reason why mpirun can -not- be threaded, assuming that all threads block and do not continuously chew cpu? Is there an environment where this would cause a problem? We don't have any machines at Sandia where I could see this being a problem. Brian -- Brian W. Barrett Dept. 1423: Scalable System Software Sandia National Laboratories _______________________________________________ devel mailing list de...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/devel
