Extoll is a graphical user interface (GUI) for preparing parallel batch jobs for submission to the LoadLeveler system. The purpose of this utility is to provide a convenient and robust way to generate a LoadLeveler command file matched to a specific parallel program, without requiring the user to manipulate a complicated script for setting up the parallel environment remotely.
Since both PVM and MPI generally require the user to play an interactive role in the set-up of the parallel environment, a job submitted through LoadLeveler must mimic the steps a user would take in an interactive environment. This is accomplished via shell commands, which are invoked when the LoadLeveler job becomes active on the queue. The Extoll utility generates a appropriate LoadLeveler command file to invoke the environment control tool (PVM or POE), set the correct number of processors, copy files to/from the local node address space, and start the user's MPMD or SPMD program(s) with the correct arguments and/or input redirection. The generated command file is also ``customizable'', by allowing for user provided setup and cleanup scripts to handle data and output file management. By providing easy, modular customization, the utility encourages users to continually leverage system supported command files, thus avoiding programming delays when system software is upgraded.
With the functionally of the system maintained and supported scripts, the ``point and click'' style X-interface, and the provision for customized setup and cleanup, Extoll has been designed to lighten the burden of submitting parallel jobs to batch queues on the NIST IBM SP2. For users without X-windows access, extoll can be used without the X-interface. In this ``line oriented'' mode, the user is prompted by a series of questions about their program. After the information is collected, a LoadLeveler command file is generated.
NOTE: Extoll is based on the utility X-llcreate (released in May 1995), and incorporates changes made to the local parallel software environment since that time.
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|Karin A. Remington|
|Mathematical and Computational Sciences Division|
|Phone: (301) 975-5119|
|Fax: (301) 990-4127|
Last change in this page: April 17, 1997 [Comments]