MPI on NOW HowTo

This document provides instructions on how to compile and run MPI programs on the NOW cluster. This document includes the followings:

Compile, link, and run MPI programs written in C.
Compile, link, and run MPI programs written in FORTRAN.
A list of available MPI materials.

Overview

MPI programs run on all poduction and development machines in the NOW cluster. The current version of MPI installed on the NOW cluster is MPICH-v1.0.12. We have ported MPICH to Generic Active Messages and Active Messages 2.0. MPI on Generic Active Messages is no longer supported.
You can find the source of MPICH libraries at /usr/now/mpi/mpich. MPI libraries are located at /usr/now/mpi/mpich/lib/solaris/{communication_protocol}/libmpi.a.
The current available communication protocols are:


Active Messages 2.0 - (am2).
Shared Memory - (ch_shmem).
P4 - (ch_p4) is no longer support for NOW.


For more up-to-date information regarding MPI on NOW, please contact Frederick Wong.

Using MPI-AM2 protocol

You can run MPI-AM2 programs on the NOW's Ultra-Sparc cluster (u0..u114).
To compile MPI programs with MPI-AM2 library, use this Makefile for C program, and this Makefile for Fortran. Try to compile with this sample hello-world.c or hello-world.f program using 'make'.

Steps to run hello-world on the NOW cluster:


1) Login to now.CS.Berkeley.EDU using Kerberos or SSH.


2) At prompt, type this to run the hello-world program:

glurun -2 -v ./hello-world


The output of the sample run is:

9:37pm now:c/ugrad/fredwong% glurun -2 -v ./hello-world
0:I am master. I am sending the message.
0:
1:I am slave. I am receiving the message.
1:The message is: Hello World!
9:37pm now:c/ugrad/fredwong%



See the glurun man page for more details.

Implementation Notes:

MPI-AM2 on NOW relies on both GLUnix and Active Messages 2.0. To run MPI-AM2 programs, you have to use GLUnix "glurun" command, not "mpirun". Use "make" or "gmake" instead of "glumake", it might not work with your MPI program. The current implementation does not take any argument. All arguments before the name of the program will be parsed by "glurun", and all arguments after the name of the program can be used by the program.. The only library available is the communication library. MPE and MPI Profiling is not available. You can force MPI programs to run on certain nodes, please refer to GLUnix man page for more information. For more information of how to use GLUnix commands, please refer to GLUnix homepage.

Frequent Asked Questions:

Using MPI-ch_shmem protocol

You can only run MPI-ch_shmem programs on the CLUMPs (clump0..clump3).
To compile MPI programs with MPI-ch_shmem library, use this Makefile for C program, and this Makefile for Fortran. Try to compile with this sample hello-world.c or hello-world.f program.

Steps to run hello-world on the CLUMPs:


1) Login to one of the CLUMPs machines.
2) At prompt, tupe this to run the hello-world program:



/usr/now/mpi/mpich/util.shmem/mpirun -np 2 ./hello-world


Specify number of parallel processes need after the argument -np.
Follows the instructions in MPI manual for details on using the command mpirun.

MPI Materials

You can get help on writing MPI programs from the following materials:

Guide for writing MPI programs - mpi.guide.ps.gz
Online Menu "mpiman" is located at


/usr/now/mpi/mpich/bin/mpiman

MPIMAN in postscript format - mpiman.ps.gz
MPI functions reference card - functions.ps.gz
MPICH Homepage

Bug Report

Please send e-mail to fredwong@cs.berkeley.edu
Please includes detail descriptions on the problems encountered.