Accurate and fast system-level power modeling

Abstract

Accurate and fast system modeling is central to the rapid design space exploration needed for embedded-system design. With fast, complex SoCs playing a central role in such systems, system designers have come to require MIPS-range simulation speeds and near-cycle accuracy. The sophisticated simulation frameworks that have been developed for high-speed system performance modeling do not address power consumption, although it is a key design constraint. In this paper, we define a simulation-based methodology for extending system performance-modeling frameworks to also include power modeling. We demonstrate the use of this methodology with a case study of a real, complex embedded system, comprising the Intel XScale®g embedded microprocessor, its WMMX™ SIMD coprocessor, L1 caches, SDRAM and the on-board address and data buses. We describe detailed power models for each of these components and validate them against physical measurements from hardware, demonstrating that such frameworks enable designers to model both power and performance at high speeds without sacrificing accuracy. Our results indicate that the power estimates obtained are accurate within 5% of physical measurements from hardware, while simulation speeds consistently exceed a million instructions per second (MIPS).