A Universal Framework for Reliable Computing-in-Memory based on Emerging Non-volatile Memories (CIMware)

内存计算（CIM）是一个新兴概念，它基于传统上分离的内存元素和处理核心的紧密集成，从而最大限度地减少跨数字架构移动数据所需的时间和精力。在新兴的器件技术中，非易失性存储器技术，如电阻或磁阻器件（STT， ReRAM和PCM），能够作为存储和信息处理单元，有利于在降低功耗的情况下提高系统的复杂性和性能。因此，它们为科学界提供了新的计算机体系结构创新的机会，能够跟踪今天的限制。虽然使用不同的记忆技术实现CIM操作有不同的风格，但CIM计算范式的体系结构设计及其在内存层次结构中的集成是开放的研究问题。此外，尽管使用新兴设备构建的基于内存计算的体系结构具有前景，但与设备本身及其双重用途（存储和计算单元）相关的许多问题仍有待解决。由于这些新兴存储技术的不成熟-与CMOS超过50年的成熟相比-以及固有的器件随机性，很难满足当今对新技术的高要求的可靠性要求。此外，可靠性的不确定性会对性能和成本产生负面影响。这些问题对CIM的可靠性提出了严峻的挑战，这可能要求在更高的抽象级别上建立基于CIM的新计算模型。该项目旨在为新兴的非易失性存储器的技术发展提供一个桥梁，从一方面实现可靠和节能的CIM，从另一方面进行架构级设计探索和计算范式。这是通过设计一个基于各种非易失性技术（忆阻和自旋电子器件）的可靠且节能的原始电路库来完成的，不仅是为了实现内存中计算架构，而且还提供准确的技术感知架构模型来基准测试和探索每种技术的潜力(例如，MRAM， PCM，ReRAM)和CIM架构设计，以支持软件和编译器设计的进一步开发以及对内存中计算范式的探索。

Computing in Memory (CIM) is an emerging concept based on the tight integration of traditionally separated memory elements and processing cores, allowing minimizing time and energy needed to move data across digital architectures. Among emerging device technologies, non-volatile memory technologies such as resistive or magneto-resistive devices (STT, ReRAM and PCM) that are able to act as both storage and information processing units, favor increasing system complexity and performance at lower power consumption. Therefore, they provide the scientific community with opportunities for new computer architecture innovations being able to track todays limitation.While there are different flavors of implementing CIM operations using different memristive technologies, the architectural design of CIM computing paradigm and their integration within the memory hierarchy are open research problems. Additionally, despite the promising nature of the in-memory computing based architectures built with emerging devices, many issues related to the devices themselves and to their dual usage (storage and computing unit) have still to be solved. Due to immaturity of these emerging memory technologies – compared to more than 50 years of CMOS maturity – as well as inherent device stochasticity, it is difficult to meet today's highly demanding reliability requirements for the new technologies. In addition, performance and cost can be negatively affected by uncertainties in reliability. These issues introduce aggressive challenges on CIM reliability, which may mandate new models of CIM-based computing at higher abstraction levels. This project aims at providing a bridge between technological developments for emerging non-volatile memories for reliable and energy-efficient CIM realization from one side and architecture-level design exploration and computing paradigms from the other side. This is done by designing a library of reliable and energy-efficient primitive circuits based on various non-volatile technologies (memristive and spintronic devices), not only in order to enable computation-in-memory architectures, but also to provide accurate technology-aware architectural models to benchmark and explore the potential of each technology (e.g., MRAM, PCM, ReRAM) and CIM architecture designs to enable further development in software and compiler design and explorations for computing-in-memory paradigm.