The Split-C on NOW HOWTO

NEW!

Split-C now runs exclusively on AM2, the new version of Active Messages!!

What you must do now to run Split-C programs

The environment has changed. Re-source the cs267.cshrc file
Older programs must be recompiled after you set up your environment
Don't use the -reserve option.
ONLY use the -reserve option for running production versions of your code. In other words, don't use the -reserve option until you have fully debugged your program.

How this affects you

You now have more nodes (~100) to run on
Fewer reservations (since they aren't needed) to contend with. Thus you should always have ~100 nodes to run on since AM2 programs don't require exclusive access to the node
No more 'xxx holding lock for lanai card' error messages
No more 'cannot open lanai copy block' error messages
Slightly slower communication performance

This document provides an overview on how to compile and run Split-C programs on the various NOW clusters. This HOWTO assumes you are familiar with Unix commands and changing your shell environment.

This document is *not* a tutorial on the language. For a good tutorial on the language itself, see Jim Demmel's Lecture on Split-C

This document is organized as follows:

Setting Your Environment

Compiling a Program

Running a Program

Setting Your Environment

Type:
source /usr/castle/proj/cs267/cs267.cshrc

Compiling a Program

Now that you have set-up your Split-C environment you are ready to compile a program. The first thing to do is create a sub-directory where you want to compile the program. Then, copy a simple Makefile into the directory and let the system makefile take care of the rest. When using the system makefile, you must use the gmake program instead of the standard make. This link shows a sample Split-C program .

Here is an example session which should get you started. Make sure you're logged into a NOW machine first!

now:>cd
now:>mkdir sc_example
now:>cd sc_example 
now:>cp /usr/castle/share/proj/split-c/develop/examples/pi/Makefile . 
now:>cp /usr/castle/share/proj/split-c/develop/examples/pi/pi.sc . 
now:>gmake 
/usr/castle/share/proj/split-c/install/LAM/bin/split-cc -g -O2 -o bin-LAM/pi.o -c pi.sc
Compiling for 2^N processors
/usr/castle/share/proj/split-c/install/LAM/bin/split-cc -o pi bin-LAM/pi.o -L/usr/sww/X11/lib -lX11 -lm

Running a Program

Assuming you have your environment variables correctly set-up, running a Split-C program is very easy. Parallel programs are invoked with the glurun program (see the NOW Tutorial for a description of glunix commands). The format for glurun is: glurun -[#of nodes] [program to run] [arguements to the program]. To see all the options for glurun, do a glurun -help.

NOTE: For most Split-C programs, you'll have to run on a power of 2 number of processors (e.g. 1,2,4,8,16)

Below is an example session of running a Split-C program.

now:>glurun -4 pi
PI estimated at 3.139500 from 1000000 trials on 4 processors.

If you have problems with Split-C, send email to split-c@boing.cs.berkeley.edu.