2.7 Setup the nodeinfo file (PVM only)

If you have installed the parallel PVM version of the ADF package you may need to set up the nodeinfo file.

The nodeinfo file tells ADF how many tasks are allowed to be run on each node in the PVM virtual parallel machine.

If you have a cluster of single CPU workstations you most probably want to generate at most one task per node. Since this is the default, you do not need to do anything special.

If one or more of your nodes have more than one CPU, you probably want to generate also more than one task one those nodes. Normally you should generate one task per CPU. The nodeinfo file communicates that information to ADF.

The format of the nodeinfo file is:

• one line per node,
• for each line: node name and a number, separated by a space.

Here node name is the name of your node, as shown using the pvm conf command. Number is the maximum number of tasks you wish to use on that node. Nodes which are not specified will default to one task to be generated at most.

Thus, if you have two SGI workstations (silly1 and silly2) with 4 CPU's each, the contents of your nodeinfo file should be (two lines):

silly1 4
silly2 4

You should put this nodeinfo file in $ADFBIN and make it readable for all ADF users.

For some special situations it makes sense to have a unique nodeinfo file for each calculation (for example when using a batch system with a large machine). For this purpose the programs within the ADF package first look for a local nodeinfo file (in the directory in which the program is started), and next it will try to use the $ADFBIN/nodeinfo file. If both do not exist, it will assume that it may generate one task per node.