Dynamic Power Management

Energy-efficient computers are becoming increasingly important in various
fields - from handheld devices to servers. Traditionally, efforts to increase
efficiency of energy use has been concentrated towards low-power hardware.
However, there is now ongoing research on power aware software as well.
Increasingly researchers are looking at how software can be optimized for power
awareness in conjunction with hardware support. With "performance/watt"
becoming an important measurement of systems, it now has become very important to look at all aspects of optimizing power consumption. Some of the software techniques being investigated include (1) scheduling power just like any other resource where each task is run at the optimal power which meets the given constraint of either delay or available power, (2) compiler techniques for lowering power consumption (reduce code size, use specialized instructions etc), (3) extension of programming model so that application is power-aware (e.g. special flag to file open request which allows OS to defer the file I/O requests so that disk can be in low power state for longer periods), (4) explicit participation of applications in power management and (5) power profile tools that can show hot spots in software. In this BoF, we would like to discuss the Seriousness of the problem at hand, some past work in this area, including our own work at enhancing the Linux kernel scheduler for dynamic CPU power management, how much of power-awareness can be hidden from applications and hardware support needed for better dynamic power management The BoF will also provide an occassion for other interested people to present their experience in related areas. Hosts: Dipankar Sarma and Srivatsa Vaddagiri