Reducing Register File Energy Consumption using Compiler Support

Most power reduction techniques have focused on gating the clock to unused functional units to minimize static power consumption, while system level optimizations have been used to deal with dynamic power consumption. After these techniques are applied, register file power consumption becomes a dominant factor in the energy consumption. This paper proposes a power-aware reconfiguration mechanism in the register file driven by a compiler. Optimal usage of the register file in terms of size is achieved and unused registers are put into a low-power state. Total energy consumption in the register file is reduced by 60%, on average, with no appreciable performance penalty. The effect of reconfiguration granularity on energy savings is also analyzed, and the compiler approach to optimize register file energy is presented.