Energy Management of Virtual Memory on Diskless Devices

In a pervasive computing environment, applications are able to run across different platforms with significantly different resources. Such platforms range from high-performance desktops to handheld PDAs. This chapter discusses a compiler approach to reduce the energy consumption of a diskless device where the swap space is provided by a remotely mounted file system accessible via a wireless connection. Predicting swapping events at compile time allows effective energy management of a PDA's wireless communication component such as a 802.11 or Bluetooth card.The compiler activates and de-activates the communication card based on compile-time knowledge of the past and future memory footprint of an application. In contrast to OS techniques, the compiler can better predict future program behavior, and can change this behavior through program transformations that enable additional optimizations.A prototype compilation system EEL_RM has been implemented as part of the SUIF2 compiler infrastructure. Preliminary experiments based on the SimpleScalar simulation toolset and three numerical programs indicate the potential benefits of the new technique.