Power-driven Real-time System Design with Energy Efficiency via ISA Customization

Compared with traditional fixed Instruction set architecture (ISA) processor, configurable processors can reduce the total number of execution cycles dramatically because the instruction set customization permits a much closer fit of the processor to target application. At the same time, custom instruction can also improve the energy efficiency remarkably. However, ISA customization does not always bring power efficiency Instead, sometimes it even increase the power consumption. To address this issue, this paper distinguishes energy efficiency from power efficiency via time granularity. Furthermore, a method combining ISA customization with frequency and voltage scaling is proposed to achieve both favorable energy and power efficiency.