HARPA: Solutions for dependable performance under physically induced performance variability

Transistor miniaturization, combined with the dawn of novel switching semiconductor structures, calls for careful examination of the variability and aging of the computer fabric. Time-zero and time-dependent phenomena need to be carefully considered so that the dependability of digital systems can be guaranteed. Already, architectures contain many mechanisms that detect and correct physically induced reliability violations. In many cases, guarantees on functional correctness come at a quantifiable performance cost. The current paper discusses the FP7-612069-HARPA project of the European Commission and its approach towards dependable performance. This project provides solutions for performance variability mitigation, under the run time presence of fabric variability/aging and built-in reliability, availability and serviceability (RAS) techniques. In this paper, we briefly present and discuss modeling and mitigation techniques developed within HARPA, covering many abstractions of digital system design: from the transistor to the application layer.