SHF: Small: Architecture-Circuit Codesign of Ultra-Low Voltage On-Chip Caches

功率效率已经成为高性能和低功耗处理器最关键的设计限制因素。为了将这类处理器的功耗降到最低，电压调节已被广泛应用为最强大的技术之一。然而，技术扩展增加了流程的可变性。这进而增加了片上存储元件在低电压下的故障概率，并将处理器的电压缩放限制在最小操作电压。在这个项目中，将探索结合电路和架构技术与信息论的协同解决方案，为未来的处理器提供可靠的、超低电压的片上高速缓存。所提出的方法的新颖之处在于通过利用1)SRAM单元大小和故障概率之间的强烈相关性，2)利用硬件和信息中的冗余来修复有缺陷的单元的现有方案和新方案的有效性，以及3)处理器存储系统在低工作电压和频率点的特性，来设计性价比高的片上高速缓存电路和结构。拟议的研究将对计算机体系结构、电路和信息理论界产生具体和重大的影响，因为它需要分析有趣和有代表性的工作负载；实现最先进的体系结构、电路和信息理论技术；以及发明强大和有用的评估方法。由于大部分开发和研究工作将由研究生进行，工业界和学术界都将受益于受过良好教育和培训的员工，以及当学生毕业并在其他地方就业时直接进行的技术转让。最后，这项研究的成功显然将对经济、教育和社会效益产生重大的社会影响，并对确保美国的领先地位起到重要作用。

Power efficiency has become the most critical design constraint for both high-performance and low-power processors. To minimize power consumption of such processors, voltage scaling has been widely used as one of the most powerful techniques. However, technology scaling increases process variability. This, in turn, increases the failure probability of on-chip memory elements at low voltages and limits voltage scaling of processors to a minimum operating voltage. In this project, synergistic solutions combining circuit and architecture techniques with information theory will be explored to provide reliable, ultra-low voltage on-chip caches for future processors. The novelty of the proposed approaches lies in designing cost- and performance-effective on-chip cache circuits and architectures by exploiting 1) the strong dependence between size and failure probability of SRAM cells; 2) the effectiveness of existing and new schemes using the redundancy in hardware and information for repairing defective cells; and 3) the characteristics of processor memory systems at low operating voltage and frequency points. The proposed research will have a specific and significant impact on the computer architecture, circuit, and information theory communities since it requires analysis of interesting and representative workloads; realization of state-of-the-art architecture, circuit, information theory techniques; and invention of powerful and useful evaluation methodologies. Since most of the development and research work will be conducted by graduate students, both industry and academia will benefit from well-educated and trained employees, as well as direct technology transfer when students graduate and begin employment elsewhere. Finally, the success of this research will clearly have a major societal impact on economic, education and social benefits, and play an important role to assure the America's leading position.