[MPICH] Binding and instance of the MPI program to a particular processor

[Christina Patrick]

Many thanks for the great help that I received from all of you'll. I
am working on modifying the mpiexec script, but it is taking me some
time as I am not really familiar with Python. I think I have figured
out where to make the changes. I will post it on the group when I
finish.

Warm Regards,
Christina.

On 6/21/07, Darius Buntinas <buntinas at mcs.anl.gov> wrote:
>
> In linux there's a command called numactl which can be used to execute a
> process and bind it to a physical processor.  Unfortunately, it looks
> like pbind can only bind a process once it has already been started.  If
> you can find a command on sun similar to numactl on linux you can do
> something like what I do with numactl.
>
> With numactl one can do something like this to bind each process to a
> different processor:
>
> mpiexec -n 1 numactl --physcpubind=0 -- myapp myapparg : -n 1 numactl
> --physcpubind=1 -- myapp myapparg : -n 1 numactl --physcpubind=2 --
> myapp myapparg
>
> etc.
>
> Of course that's messy, so a more general solution would be to write a
> script called, e.g. execbind, to do that:
>
> numactl --physcpubind=`expr $PMI_RANK % $PROCS_PER_NODE` -- $@
>
> Where $PROCS_PER_NODE is the number of processors on each node of your
> cluster, and $PMI_RANK is set by mpiexec.
>
> Then, if you wanted to start 16 processes on a cluster of machines with
> 4 cores each, you could simply do:
>
> mpiexec -n 16 -env PROCS_PER_NODE 4 execbind myapp myapparg
>
> Darius
>
> Christina Patrick wrote:
> > Is it possible for me to modify the Python script (mpiexec) in such a
> > way that I use the pbind command to bind each instance of the executing
> > program to a different processor? I would like to give that a shot.
> >
> > Warm Regards,
> > Christina.
> >
> >
> > On 6/20/07, *Rajeev Thakur* <thakur at mcs.anl.gov
> > <mailto:thakur at mcs.anl.gov>> wrote:
> >
> >     MPICH2 leaves the scheduling of processes to the OS. If the OS has
> >     some way
> >     to bind processes to processors, you could try using it.
> >
> >     Rajeev
> >
> >      > -----Original Message-----
> >      > From: owner-mpich-discuss at mcs.anl.gov
> >     <mailto:owner-mpich-discuss at mcs.anl.gov>
> >      > [mailto:owner-mpich-discuss at mcs.anl.gov
> >     <mailto:owner-mpich-discuss at mcs.anl.gov>] On Behalf Of
> >      > Christina Patrick
> >      > Sent: Wednesday, June 20, 2007 4:12 PM
> >      > To: mpich-discuss-digest at mcs.anl.gov
> >     <mailto:mpich-discuss-digest at mcs.anl.gov>
> >      > Subject: [MPICH] Binding and instance of the MPI program to a
> >      > particular processor
> >      >
> >      > Hi everybody,
> >      >
> >      > I am having a 8 processor Solaris 9 machine and I want to
> >      > execute an MPI program on it. The problem is that the tasks
> >      > created by mpiexec keep migrating on the different
> >      > processors. Since it is only one machine, there is only one
> >      > instance of the mpdboot daemon running on the machine. Hence
> >      > when I execute the below command on the machine with 8
> >      > processors, I get an output that says:
> >      >
> >      > (For example, if the MPI program name is "finalized")
> >      > # mpiexec -n 8 ./finalized
> >      > 0:  No Errors
> >      >
> >      > When I examined the system using the "prstat" command, I
> >      > observed that the tasks are migrating between the different
> >      > processors.
> >      >
> >      > Is there any why in which I could bind each instance of the
> >      > MPI program to a different processor.
> >      >
> >      > Your suggesstions and help is appreciated,
> >      >
> >      > Thanks,
> >      > Christina.
> >      >
> >
> >
>