Optimisation Framework

Contents

We introduced in Chapter 4 the ZENTURIO experiment management tool for multi-experimental performance and parameter studies of parallel applications. To achieve this goal, ZENTURIO performs an automatic exhaustive sweep of the entire parameter space defined using the ZEN directive-based experiment specification language described in Chapter 3.

With the emergence of Grid computing that aggregates a potentially unbounded number of resources, new classes of applications such as workflows and parameter studies are of increasing interest to the scientists. The parameter space of such large scale Grid applications can easily achieve rather huge dimensions for which the exhaustive parameter sweep performed by ZENTURIO is no longer a feasible solution. In general, a complete parameter sweep gives useful detailed insight on the application behaviour but also produces vast amounts of data that are irrelevant for further studies. Often the user’s ultimate goal is to find parameter combinations that optimise a certain application behaviour, such as a performance metric or an output result. Such optimisation problems are known as NP-complete [85] and require advanced heuristics to find approximate or reasonably good solutions.