IBM p690

Compiling

Use in your Makefile:

 INC_MPI    = -I/usr/lpp/ppe.poe/include
 LIB_MPI    = -L/usr/lpp/ppe.poe/lib -lmpi

And, of course, add them appropriately to you compiler and linker flags, respectively:

 INCS += $(INC_MPI)
 LIBS += $(LIB_MPI)

Don't link or compile with mpicc. It's not necessary.

Running MPI from the command line

Most jobs should be submitted to the queue. However, for quick runs, MPI processes can be run from the command line.

First, you need a ~/.rhosts file containing the single line:

cuillin

Just execute the following:

echo cuillin >> $HOME/.rhosts
chmod go-rwx $HOME/.rhosts

Your MPI-enabled programme can be run from the command line as:

mpiexec -n 4 ./MyMPIcode My.ICs -hostfile hostfile

where hostfile contains:

cuillin
cuillin
cuillin
cuillin

In the previous example, 4 MyMPIcode processes will be started, hence hostfile requires 4 'cuillins'.

Jobs run directly from the command line should not run longer than an hour. Also, command-line runs should not be used for benchmarking, unless you know the queue is empty, as your processes will be sharing CPU resources with other processes.

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