Note that the "migrate me from my current node to node <foo>" scenario is covered by the migration API exported by the C/R infrastructure, as I noted earlier. http://osl.iu.edu/research/ft/ompi-cr/api.php#api-cr_migrate
The "move rank N to node <foo>" scenario could probably be added as an extension of this interface (since you can do that via the command line now) if that is what you are looking for. -- Josh On Thu, Nov 10, 2011 at 11:03 AM, Ralph Castain <r...@open-mpi.org> wrote: > So what you are looking for is an MPI extension API that let's you say > "migrate me from my current node to node <foo>"? Or do you have a rank that > is the "master" that would order "move rank N to node <foo>"? > Either could be provided, I imagine - just want to ensure I understand what > you need. Can you pass along a brief description of the syntax and > functionality you would need? > > On Nov 10, 2011, at 8:27 AM, Mudassar Majeed wrote: > > Thank you for your reply. In our previous publication, we have figured it > out that run more than one processes on cores and balancing the > computational load considerably reduces the total execution time. You know > the MPI_Graph_create function, we created another function MPI_Load_create > that maps the processes on cores such that balance of computational load can > be achieved on cores. We were having some issues with increase in > communication cost due to ranks rearrangements (due to MPI_Comm_split, with > color=0), so in this research work we will see how can we balance both > computation load on each core and communication load on each node. Those > processes that communicate more will reside on the same node keeping the > computational load balance over the cores. I solved this problem using ILP > but ILP takes time and can't be used in run time so I am thinking about an > heuristic. That's why I want to see if it is possible to migrate a process > from one core to another or not. Then I will see how good my heuristic will > be. > > thanks > Mudassar > > ________________________________ > From: Jeff Squyres <jsquy...@cisco.com> > To: Mudassar Majeed <mudassar...@yahoo.com>; Open MPI Users > <us...@open-mpi.org> > Cc: Ralph Castain <r...@open-mpi.org> > Sent: Thursday, November 10, 2011 2:19 PM > Subject: Re: [OMPI users] Process Migration > > 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
