Automatic Runtime Customization for Variability Awareness on Multicore Platforms

Driven by increasingly aggressive CMOS technology scaling, sub-wavelength lithography is incurring more evident variability in the technology parameters of the semiconductors fabrication process. That variability results in otherwise identical designs displaying very different performances, power consumption levels and lifespans once fabricated. Hence, process variability may lead to execution uncertainties, impacting the expected quality of service and energy efficiency of the running software. As such uncertainties are intolerable in certain application domains such as automotive and avionic infotainment systems, it has become a persistent necessity to customize runtime engines to introduce measures for variability awareness in task allocation decisions. The purpose of compensating process variability is to avoid performance degradation and energy inefficiency. And customization is meant to take place automatically through exporting the variability-impacted platform characteristics - such as per-core manufactured clock frequency - for the runtime library to perform variability-aware workload sharing on the target cores of the hardware platform. Hence, we can eventually achieve noticeable optimization results, not only on the system performance and energy consumption levels, but also in increasing productivity in systems development, testing, integration, and marketing. This paper presents a holistic approach starting from a system model of the target multicore platform, to building and integrating the runtime library, and finally highlighting the optimization results achieved through the proposed runtime customization paradigm.