Combining compiler and operating system support for energy efficient i/o on embedded platforms

Mobile and embedded platforms have experienced dramatic advances in capabilities, largely due to the development of associated peripheral devices for storage and communication. The incorporation of these I/O devices has increased the overall power envelope of these platforms. In fact, system-level power consumption of mobile platforms is often dominated by peripheral devices. Since battery technologies alone have been unable to provide the lifetimes required by many platforms, in order to conserve energy, most devices provide the ability to transition into low power states during idle periods. The resulting energy savings are heavily dependent upon the lengths and number of idle periods experienced by a device. This paper presents an infrastructure designed to take advantage of device low power states by increasing the burstiness of device accesses and idle periods to provide a reduced power profile, and thereby an improvement in battery life. Our approach combines compiler-based source modifications with operating system support to implement a dynamic solution for enhanced energy consumption. We evaluate our infrastructure on an XScale-based embedded platform with a Linux implementation. 1