[mpich-discuss] SMP and mpd.hosts

[Torquil Macdonald Sørensen]

Hi all,

I would like to ask for some help concerning the use of MPICH2 1.1 on a 
dual-core machine with Linux. My mpich2 innstallation uses the nemesis 
communication device, which I thought was able to utilise both cores, in 
addition to communicate through the network.

 From before (maybe from mpich1?) I had a mpd.hosts file with the 
following syntax:

dagda.uio.no:2
#styx.uio.no:2

where the :2 was to indicate the number of CPUS. styx.uio.no is 
commented out because this time I want two processes to run on 
dagda.uio.no. But I am no longer sure of this syntax since I cannot find 
it in the documentation. I was hoping that the following would work:

$ mpdboot -n 2
$ mpiexec -n 2 ./Executable

However, mpdboot complains:

"totalnum=2  numhosts=1
there are not enough hosts on which to start all processes"

What it the common method to run a program so that it will be able to 
distribute itself across several cpu-cores in one machine, and also 
across the network, if I e.g. decomment styx.uio.no and use -n 4 in the 
above commands?

Best regards
Torquil Sørensen