BVF: Enabling Significant On-Chip Power Savings via Bit-Value-Favor for Throughput Processors

摘要

Power reduction is one of the primary tasks for designing modern processors, especially for high-performance throughput processors such as GPU due to their high power budget. In this paper, we propose a novel circuit-architecture co-design scheme to harvest enormous power savings for GPU on-chip SRAM and interconnects. We propose a new 8T SRAM that exhibits asymmetric energy consumption for bit value 0/1, in terms of read, write and standby. We name this feature Bit-Value-Favor (BVF). To harvest the power benefits from BVF on GPUs, we propose three coding methods at architectural level to maximize the occurrence of bit-1s over bit-0s in the on-chip data and instruction streams, leading to substantial chip-level power reduction. Experimental results across a large spectrum of 58 representative GPU applications demonstrate that our proposed BVF design can bring an average of 21% and 24% chip power reduction under 28nm and 40nm process technologies, with negligible design overhead. Further sensitivity studies show that the effectiveness of our design is robust to DVFS, warp scheduling policies and different SRAM capacities.