On Mar 1, 2012, at 3:33 AM, Pinero, Pedro_jose wrote: > I am launching 200 light processes in two computers with 8 cores each one > (Intel i7 processor). They are dedicated and are interconnected through a > point-to-point Gigabit Ethernet link. > > I read about oversubscribing nodes in the open-mpi documentation, and for > that reason I am using the option > > - Mca mpi_yield_when_idle 1
That's still going to give you terrible performance. Open MPI was designed to run basically at one process per processor (usually a core). The easiest reason to cite here is that Open MPI busy-polls while blocking for message passing progress. The yield_when_idle option *helps* (in some versions of Linux, at least), but it doesn't change that fact that MPI processes will be extremely aggressive in clamoring for CPU cycles. -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
