Space-efficient time-series call-path profiling of parallel applications

Abstract

The performance behavior of parallel simulations often changes considerably as the simulation progresses - with potentially process-dependent variations of temporal patterns. While call-path profiling is an established method of linking a performance problem to the context in which it occurs, call paths reveal only little information about the temporal evolution of performance phenomena. However, generating call-path profiles separately for thousands of iterations may exceed available buffer space - especially when the call tree is large and more than one metric is collected. In this paper, we present a runtime approach for the semantic compression of call-path profiles based on incremental clustering of a series of single-iteration profiles that scales in terms of the number of iterations without sacrificing important performance details. Our approach offers low runtime overhead by using only a condensed version of the profile data when calculating distances and accounts for process-dependent variations by making all clustering decisions locally.