Power Management of Computing Environments According to the User Context

This research started from April 2010 funded by Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research (B).

The power consumption of IT devices occupies about 5 percent of the Japan's total power consumption in 2006, and this is estimated to grow up to 25 percent in 2025 (predicted by the Ministry of Economy, Trade and Industry: Green IT Initiative). Thus the reduction of power consumption is an urgent issue.

There are two types of information systems; (1) back-end systems such as data centers, which do not have direct interaction with users and (2) front-end systems such as mobile laptops and desktop computers that compute in response to user requests. Front-end systems are often idle and not always processing so if they are always turned on, the percentage of time when they are wasting power would be much higher than that of back-end systems. The number of front-end systems is drastically increasing today and they tend to be embedded with high performance/power-consuming processors and network interfaces like back-end systems recently. Therefore, the increase of these wasted power becomes a serious problem.

This research targets to save power consumption of these front-end information systems. Though these systems quite often have idle time with no processing requests from users, if we adopt reactive power management which wakes up the required components at the arrival of requests, users would feel much uncomfortable. We aim to realize a power saving computing environment without degrading the user comfortability. To achieve this goal, first we estimate when and what the users require for a system, i.e. user context between users and information systems through monitoring user activities. By utilizing the estimation, we will develop a proactive power management method by cooperatively controlling the hardware and system software.