Dynamic Register File Partitioning in Superscalar Microprocessors for Energy Efficiency

Abstract

Register file is one of the vital and energy consuming parts inside microprocessor. Many studies show that it is one of the hot spots on the chip. It is also observed by many researchers that many of the produced values in a processor are narrow. By using the narrow values, register files can store fewer bits and may be designed to need less static and dynamic energy. In this paper we propose a register file design that stores data in narrow value groups and values are written to those groups according to their widths. Size of narrow value groups can be set dynamically according to the behavior of the program while having the same performance. We show that the register file which has dynamically changing narrow value groups offers static and dynamic energy savings in the register file up to 65% with negligible performance loss.