On Tue, 2009-04-21 at 19:19 -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.
The short response is: why do you not want it to use the whole CPU while waiting? There's some discussion starting here: <http://www.open-mpi.org/community/lists/users/2008/04/5457.php> If you really want to make your application run slower, you can yield the CPU when not doing much: <http://www.open-mpi.org/faq/?category=running#force-aggressive-degraded> Ciao Terry -- Dr. Terry Frankcombe Research School of Chemistry, Australian National University Ph: (+61) 0417 163 509 Skype: terry.frankcombe
