Mpirun stuff

MPIRUN Use

which mpirun   //Makes sure mpirun is in your path
lscpu          //Find out about the hardware you're using (You can find # of cores)

mpirun -np 3 /full/path/to/file/hello_c
mpirun -np 3 --display-map /full/path/to/file/hello_c
mpirun -np 3 --oversubscribe /full/path/to/file/hello_c
mpirun -np 2 -host hostName file
mpirun -np 2 --host hostName,hostName2 file

mpirun -np 2 fileName : -np 2 fileName        //Run two files

https://www.open-mpi.org/faq/?category=running#mpirun-hostfile Create a file and add the name of the hosts into it. My host file is called "myhosts". In it, I just have the hostname of my raspberry pi.

mpirun -np 8 --hostfile myhosts fileName

You can use mpirun in files too to run multiple commands or refer to multiple files:

mpirun --app my_appfile

In my_appfile:
-np 2 fileName
-np 2 anotherName

A great way to check where your tests/jobs are running is to create a runs on script:

runsOn.sh
#!/bin/sh
echo "Machine test: $HOSTNAME"

Example of an MCA parameter (See the "backbone" section for more info)

mpirun -np 4 -mca plm_rsh_args "-p2222" ls   //Allows the use of port 2222 for ssh instead of the default 22

MPIRUN for NFS

Locate the openmpi-default-hostfile file. It's located where Open MPI was built. All of the Open MPI commands will be located in /bin of this folder while the hostfile is located in the /etc folder that is at the same level as the /bin folder. Add the ip address or hostname to it. Note, check /usr/local/bin and /usr/local/etc. Those are the most likely places the /bin and /etc folders will be.

Example:

<IP address>:4           //OR
frutilla

The "Backbone" for much of Open MPI's functionality

https://www.open-mpi.org/faq/?category=tuning