vEC: Virtual Energy Counters

Energy has become a critical issue in processor design, especially in embed ded environments. Thus, there is a need for tools, which provide an accurat e and fast estimation of energy. In this paper, we present the design and u se of a tool, Virtual Energy Counters (vEC), for estimating the energy cons umption of user programs. vEC is built on top of the Perfmon user library f or the UltraSPARC platfom-4 and provides a user interface, which can be use d within user programs to estimate the energy consumption. The energy estim ates are provided for those consumed in the data, instruction and extended caches, main memory, address bus, data bus, address pads, and data pads.