Hi, > Am 11.10.2016 um 14:56 schrieb Mark Potter <mpot...@pcpcdirect.com>: > > This question is related to OpenMPI 2.0.1 compiled with GCC 4.8.2 on > RHEL 6.8 using Torque 6.0.2 with Moab 9.0.2. To be clear, I am an > administrator and not a coder and I suspect this is expected behavior > but I have been asked by a client to explain why this is happening. > > Using Torque, the following command returns the hostname of the first > node only, regardless of how the nodes/cores are split up: > > mpirun -np 20 echo "Hello from $HOSTNAME"
The $HOSTNAME will be expanded and used as argument before `mpirun` even starts. Instead it has to be evaluated on the nodes: $ mpirun bash -c "echo \$HOSTNAME" > (the behaviour is the same with "echo $(hostname)) > > The Torque script looks like this: > > #PBS -V > #PBS -N test-job > #PBS -l nodes=2:ppn=16 > #PBS -e ERROR > #PBS -o OUTPUT > > > cd $PBS_O_WORKDIR > date > cat $PBS_NODEFILE > > mpirun -np32 echo "Hello from $HOSTNAME" > > If the echo statement is replaced with "hostname" then a proper > response is received from all nodes. > > While I know there are better ways to test OpenMPI's functionality, > like compiling and using the programs in examples/, this is the method > a specific client chose. There are small "Hello world" programs like here: http://mpitutorial.com/tutorials/mpi-hello-world/ to test whether e.g. the libraries are found at runtime by the application(s). -- Reuti > I was using both the examples and a Torque job > script calling just "hostname" as a command and not using echo and the > client was using the script above. It took some doing to figure out why > he thought it wasn't working and all my tests were successful and when > I figured it, he wanted an explanation that's beyond my current > knowledge. Any help towards explaining the behaviour would be greatly > appreciated. > > -- > Regards, > > Mark L. Potter > Senior Consultant > PCPC Direct, Ltd. > O: 713-344-0952 > M: 713-965-4133 > S: mpot...@pcpcdirect.com > _______________________________________________ > users mailing list > users@lists.open-mpi.org > https://rfd.newmexicoconsortium.org/mailman/listinfo/users > _______________________________________________ users mailing list users@lists.open-mpi.org https://rfd.newmexicoconsortium.org/mailman/listinfo/users
