Compiler and runtime support for predictive control of power and cooling

The low cost of clusters built using commodity components has made it possible for many more users to purchase their own supercomputer. However, even modest-sized clusters make significant demands on the power and cooling infrastructure. Minimizing impact of problems after they are detected is not as effective as avoiding problems altogether. This paper is about achieving the best system performance by predicting and avoiding power and cooling problems. Although measuring power and thermal properties of a code is not trivial, the primary issue is making predictions sufficiently in advance so that they can be used to drive predictive, rather than just reactive control at runtime. This paper presents new compiler analysis supporting interprocedural power prediction and a variety of other compiler and runtime technologies making feed-forward control feasible. The techniques apply to most computer systems, but some properties specific to clusters and parallel supercomputing are used where appropriate.