Critical power slope: understanding the runtime effects of frequency scaling

摘要: Energy efficiency is becoming an increasingly important feature for both mobile and high-performance server systems. Most processors designed today include power management features that provide processor operating points which can be used in algorithms. However, existing algorithms implicitly assume lower performance are more energy efficient than higher points. Our empirical observations indicate many systems, this assumption not valid.We introduce a new concept called critical slope to explain capture the power-performance characteristics of systems with features. We evaluate three - clock throttled Pentium laptop, frequency scaled PowerPC platform, voltage system demonstrate benefits our approach. evaluation based on measurements first two publicly available data third. Using slope, we why Pentium-based system, it run only at highest frequency, while PowerPC-based lowest point. confirm results by measuring behavior web serving benchmark. Furthermore, extend understand scaling when combined scaling. show some cases, may reduce below certain