SHF: Small: Virtualization of Heterogeneous and Non-Uniform Memory Hierarchy

硬件存储器设备是分层结构的，并且越来越异构（在易失性、能量效率和可靠性方面）和不均匀（在延迟和带宽方面）。然而，现有的内存虚拟化技术仅仅为每个虚拟机提供了一个扁平、同质、统一的内存空间，这是对硬件内存资源的不透明、扭曲的抽象。 这种抽象对虚拟机中的应用程序提出了很大的挑战，以有效地利用内存资源。云计算平台和其他虚拟化平台构成了工业、军事、学术界和更广泛人群使用的现代计算基础设施的骨干。该项目大大改进了内存虚拟化技术，使这些平台上的应用程序可以充分利用硬件内存资源的异构性、非均匀性和其他特性，以提高性能、能效和可靠性。该项目涉及本科生和研究生与虚拟化和云工作。这将为他们提供强大的编程和系统能力，以在云计算行业工作。该项目探索新颖的内存虚拟化技术，为每个虚拟机提供一个完整的虚拟内存层次结构，由虚拟缓存设备和异构虚拟内存设备组成。虚拟存储器层次结构有效地用作虚拟机和虚拟机监视器之间的表达接口。对于虚拟机而言，它忠实地反映了底层硬件内存资源的特征和架构，基于此可以有效地应用内存感知和缓存感知优化技术。对于虚拟机监控器，虚拟设备的使用情况反映了虚拟机上的工作负载对不同类型内存资源的需求，基于此可以很好地协调内存资源的共享。研究的重点是：1）软件框架和关键硬件支持，可以建立虚拟存储层次结构中的虚拟设备上的各种类型的硬件存储设备，并保持其功能和结构的低成本; 2）的技术，以有效地共享不同类型的虚拟机之间的内存资源;和3）验证现有的缓存感知和内存感知技术的虚拟存储层次结构。为了促进成果的传播，预期的框架和技术将内置于Linux操作系统和虚拟机监视器（如基于内核的虚拟机（KVM））中，并开放给社区共享。

Hardware memory devices are hierarchically structured and increasingly heterogeneous (in terms of volatility, energy efficiency, and reliability) and non-uniform (in terms of latency and bandwidth). However, existing memory virtualization technology only provides each virtual machine with a flat, homogeneous, and uniform memory space, which is an opaque and distorted abstraction of hardware memory resources. This abstraction poses great challenges for applications in virtual machines to make efficient utilization of memory resources. Cloud computing platforms and other virtualized platforms form the backbone of the modern computing infrastructures used by industry, military, academia, and the wider population. The project substantially improves memory virtualization technology, so that applications on these platforms can fully leverage the heterogeneity, non-uniformity, and other features of hardware memory resources to improve performance, energy efficiency, and reliability. The project involves undergraduate and graduate students to work with virtualization and the cloud. This will provide them with strong programming and system capabilities to work in the cloud computing industry.The project explores novel memory virtualization techniques to provide each virtual machine with a complete virtual memory hierarchy that consists of virtual cache devices and heterogeneous virtual memory devices. The virtual memory hierarchy effectively serves as an expressive interface between a virtual machine and the virtual machine monitor. For a virtual machine, it faithfully reflects the features and architectures of underlying hardware memory resources, based on which memory-aware and cache-aware optimization techniques can be effectively applied. For the virtual machine monitor, the usage of virtual devices reflects the demand of the workload on a virtual machine for different types of memory resources, based on which the sharing of memory resources can be well coordinated. The investigation focuses on 1) the software framework and critical hardware support that can build virtual devices in virtual memory hierarchy on top of diverse types of hardware memory devices and maintain their features and structures with low cost; 2) the techniques to efficiently share different types of memory resources between virtual machines; and 3) validating existing cache-aware and memory-aware techniques on virtual memory hierarchy. To spur the dissemination of results, the expected framework and techniques will be built into Linux OS and virtual machine monitor such as Kernel-based Virtual Machine (KVM), and be open to the community for sharing.