Gernot Heiser, UNSW and NICTA - Realistic Energy Management

Abstract: Managing energy effectively is important for battery-powered devices, and is an active area of research. However, much research is based on assumptions which, as we show, do not hold for modern devices, and can lead to catastrophically incorrect results (such as maximising energy use when attempting to minimise). Energy-management research must therefore be based on measurements, rather than just theoretical models. It also needs to focus on those sub-systems which are actually the main consumer of energy.

The talk presents a study of energy consumption of smartphones, representing an important class of battery-powered devices. It also discusses practical approaches to building realistic power models of power consumption, and shows their use in managing energy of real devices. Specifically I will discuss management of CPU energy using dynamic frequency and voltage scaling (DVFS) together with sleep modes, and initial results for I/O devices. I will present some data indicating that DVFS is about to reach its use-by date and speculate on what to do with multicores.

Bio: Gernot Heiser holds the John Lions Chair of Operating Systems at the University of New South Wales (UNSW), and leads the Trustworthy Embedded Systems (ERTOS) group at NICTA, Australia's National Centre of Excellence for ICT Research. He joined NICTA at its creation in 2002, and before that was a full-time member of academic staff at UNSW from 1991. His past work included the Mungi single-address-space operating system, several un-broken records in IPC performance, and the best-ever reported performance for user-level device drivers.

In 2006, Gernot with a number of his students founded Open Kernel Labs, now the market leader in secure operating-systems and virtualization technology for mobile wireless devices. The company's OKL4 operating system, a descendent of L4 kernels developed by his group at UNSW and NICTA, is deployed in more than 750 million mobile phones. This includes the Motorola Evoke, the first (and to date only) mobile phone running a high-level OS (Linux) and a modem stack on the same processor core.

In a former life, Gernot developed semiconductor device simulators and models of device physics for such simulators, and pioneered the use of three-dimensional device simulation for the characterisation and optimisation of high-performance silicon solar cells.