Brainware for green HPC

Abstract

The reduction of the infrastructural costs of HPC, in particular power consumption, currently is mainly driven by architectural advances in hardware. Recently, in the quest for the EFlop/s, hardware-software codesign has been advocated, owing to the realization that without some software support only heroic programmers could use high-end HPC machines. However, in the topically diverse world of universities, the EFlop/s is still very far off for most users, and yet their computational demands shape the HPC landscape in the foreseeable future. Based on experiences made at RWTH Aachen University and in the context of the distributed Computational Science and Engineering support of the UK HECToR program, we claim based on economic considerations that HPC hard- and software installations need to be complemented by a “brainware” component, i.e., trained HPC specialists supporting performance optimization of users’ codes. This statement itself is not new, and the establishment of simulation labs at HPC centers echoes this fact. However, based on our experiences, we quantify the savings resulting from brainware, thus providing an economic argument that sufficient brainware must be an integral part of any “green” HPC installation. Thus, it also follows that the current HPC funding regimes, which favor iron over staff, are fundamentally flawed, and long-term efficient HPC deployment must emphasize brainware development to a much greater extent.