Xtream-fit: an energy-delay efficient data memory subsystem for embedded media processing

Due to the critical role played by data memory subsystems in the performance and energy efficiency of embedded systems, the design of energy-efficient data memory architectures has received considerable attention in recent years. In this paper, we propose a novel special-purpose data memory subsystem called Xtream-Fit which is aimed at achieving high energy-delay efficiency for streaming media applications. A key novelty of Xtream-Fit is that it exposes a single customization parameter, thus enabling a very simple and yet effective design space exploration methodology. A second key contribution of this paper is the ability to achieve very high energy-delay efficiency through a synergistic combination of: 1) special purpose memory subsystem components, namely, a streaming memory and a scratch-pad memory and (2) a novel task-based execution model that exposes/enhances opportunities for efficient prefetching, and aggressive dynamic energy conservation techniques targeting on-chip and off-chip memory components. Extensive experimental results show that Xtream-Fit reduces the energy-delay product by 22% to 61%, as compared to general-purpose memory subsystems enhanced with state of the art cache decay and SDRAM power-mode control policies.