Replicating HPC I/O workloads with proxy applications

Large scale simulation performance is dependent on a number of components, however the task of investigation and optimization has long favored computational and communication elements above I/O. Manually extracting the pattern of I/O behavior from a parent application is a useful way of working to address performance issues on a per-application basis, but developing workflows with some degree of automation and flexibility provides a more powerful approach to tackling current and future I/O challenges. In this paper we describe a workload replication workflow that extracts the I/O pattern of an application and recreates its behavior with a flexible proxy application. We demonstrate how simple lightweight characterization can be translated to provide an effective representation of a physics application, and show how a proxy replication can be used as a tool for investigating I/O library paradigms.