Techniques for High Performance Computational Steering

Jeffrey Vetter
University of Illinois at Urbana-Champaign

March 1, 1999
2:30 - 3:30 p.m.
Room 3-125 EE/CS Bldg.

Abstract

Interactive computational steering is a technique that allows users to
analyze, calibrate, and correct the execution of simulations at  
runtime. Computational steering can provide impressive capabilities for users. However, computer scientists face numerous challenges to make steering an
effective tool.  One challenge, which is our focus, is to develop
efficient techniques for steering that support many HPC applications while  
providing sufficient flexibility for various types of interaction.

In this talk, we examine efficient strategies for designing computational
steering infrastructures and outline our practical experiences using  
steering on four existing scientific applications. Our strategy, called
language-directed computational steering, dynamically optimizes steering  
requests at runtime to manage both application performance and steering
latency.  In this model, users issue steering requests as micro-language
statements to the steering system. The steering system, in turn, parses and
optimizes these requests. Then, it uses the application's instrumentation to  extract data or to inject modifications.  In one example, the 'locality'
optimization improved steering latency by two orders of magnitude.

In the second part of the talk, we enumerate the basic steps needed to enable computational steering on our example applications and we evaluate the
steering infrastructure's impact on application performance. Finally, we
furnish a summary of the common issues distilled from these experiences and
propose some future research directions.

Post-Colloquium Reception will be held
in the EE/CS 5th Floor Lounge from 3:30 to 4:00 p.m.