The MPI standard does not provide explicit support for process migration. However, some MPI implementations (including Open MPI) have integrated such support based on checkpoint/restart functionality. For more information about the checkpoint/restart process migration functionality in Open MPI see the links below: http://osl.iu.edu/research/ft/ompi-cr/ http://osl.iu.edu/research/ft/ompi-cr/tools.php#ompi-migrate
I even implemented an MPI Extensions API to this functionality so you can call it from within your application: http://osl.iu.edu/research/ft/ompi-cr/api.php#api-cr_migrate These pieces of functionality are currently only available in the Open MPI development trunk. -- Josh On Thu, Nov 10, 2011 at 8:19 AM, Jeff Squyres <jsquy...@cisco.com> wrote: > 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/ > > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users > > -- Joshua Hursey Postdoctoral Research Associate Oak Ridge National Laboratory http://users.nccs.gov/~jjhursey
