Introduction to using the SP2

Hardware

The SP2 consists of a control workstation (sp2-cw) and 16 processing nodes (sp2-01, sp2-02, etc..). Generally speaking, one should not need to login directly to the processing nodes; all jobs should be run from the control workstation (sp2-cw). In addition to standard ethernet, the processing nodes are interconnected through a high performance switch. The switch interfaces are associated with the names sp2-n01, sp2-n02, etc.. When using TCP/IP, make sure to use the switch names to get better performance. Note that the control workstation is NOT connected to the switch.

A second standalone RS6000 (sp2-cw2) can be used for compiling. The IBM compilers are only available on this machine. The MPI libraries and compiling tools are installed on sp2-cw2. However, this machine cannot be used to run parallel jobs; that has to be done from sp2-cw.

Logging in

To login to sp2-cw or sp2-cw2, use rlogin from any CS workstation with the -F (forward ticket) option:

    rlogin -F sp2-cw

You'll want to add /p/sp2/bin to your path, as many common commands are found there; there is no /s/std for AIX. You might also want to add /usr/lpp/ssp/bin, where most of the parallel commands are found. If you don't specify the -F option to rlogin, you will get logged in but will not have any AFS access.

Getting help

There are only a few man pages on the SP2; most of the useful documentation can be accessed through the info program. Here's a few hints to get info to work for you:

Make sure that your DISPLAY environment variable is set. If it is not set, info will start up the text client instead of the X client.
info will need write access to a subdirectory called info in what it thinks is your home directory. The recommended way of doing this is to create a directory under /tmp and direct info to use it by running it from a script that looks like this:
```
#!/p/sp2/bin/tcsh
setenv HOME /tmp/mydirectory
/bin/info $*
```
The default library is the AIX info library. You can use the -l option to request other libraries. Available libraries are:
- pe: Parallel computing environment
- sp2: SP2 specific documentation
- C: C for AIX
- cset: cset compiler

Questions can also be mailed to lab or to dionne, but please make sure that you've read the relevant documentation before asking questions.

Compiling

gcc version 2.7.2.2-1.2 is available as /p/sp2/bin/gcc. IBM's compiler (cc, CC, xlc, xlC) is available only on sp2-cw2, due to licensing reasons.

Using MPI

Note that you can NOT use gcc to build MPI executables that use the IBM supplied MPI libraries. MPI requires special "start" files that are only compatible with IBM's compiler. You should build your programs with the mpcc or mpCC commands on sp2-cw2. For more information about MPI and how to run your programs, please consult the pe info library.

Last updated Fri Mar 20 12:30:33 CST 1998 by Marc Dionne

dionne@cs.wisc.edu