Hi Ross: On Tue, Apr 21, 2009 at 07:19:53PM -0700, Ross Boylan wrote: > I'm using Rmpi (a pretty thin wrapper around MPI for R) on Debian Lenny > (amd64). My set up has a central calculator and a bunch of slaves to > wich work is distributed. > > The slaves wait like this: > mpi.send(as.double(0), doubleType, root, requestCode, comm=comm) > request <- request+1 > cases <- mpi.recv(cases, integerType, root, mpi.any.tag(), > comm=comm) > > I.e., they do a simple send and then a receive. > > It's possible there's no one to talk to, so it could be stuck at > mpi.send or mpi.recv. > > Are either of those operations that should chew up CPU? At this point, > I'm just trying to figure out where to look for the source of the > problem.
Search the list archives http://www.open-mpi.org/community/lists/users/ for "100% CPU" and you will get lots to look at. I had a similar problem with a FORTRAN program. With the help of Jeff Squyres and Eugene Loh I wrote a solution: user-written MPI_Recv.c and MPI_Send.c which I load them with my application, and the MPI problem "100% CPU usage while doing nothing" is cured. The code for MPI_Recv.c and MPI_Send.c is here: http://www.open-mpi.org/community/lists/users/2008/12/7563.php Cheers, Douglas.
