It is widely acknowledged that even as VLSI technology advances, there is a looming crisis that is an important obstacle to the widespread deployment of mobile embedded devices, namely that of power. This problem can be tackled at many levels like devices, logic, operating systems, microarchitecture and compiler. While there have been various proposals for specific compiler optimizations for power, there has not been any attempt to systematically map out the space for possible improvements. In this paper, we quantitatively characterize the limits of what a compiler can do in optimizing for power using precise modeling of a state-of-the-art embedded processor in conjunction with a robust compiler. We provide insights to how compiler optimizations interact with the internal workings of a processor from the perspective of power consumption. The goal is to point out the promising and not so promising directions of work in this area, to guide the future compiler designer.
Lakshmi N. Chakrapani, Pinar Korkmaz, Vincent John