CAREER: In-Kernel Execution of Storage Functions

新兴的硬件存储设备可以实现每秒数百万次的操作。它们还可以在短短2-3微秒内访问数据，这比传统的闪存和硬盘技术提高了一个数量级。然而，在如此低的延迟下，操作系统和文件系统的开销成为端到端存储性能的重大瓶颈。存储请求可能会减慢2倍或更多。该项目设计了XRP(快速重新提交路径)，这是一个Linux支持的框架，允许应用程序编写可以由操作系统执行的存储功能。XRP允许应用程序几乎完全绕过操作系统和文件系统的开销。主要的研究挑战是，通过绕过操作系统的存储层，XRP缺少有关用户请求的重要上下文，例如谁拥有它正在访问的块，以及如何安全和并发地遍历应用程序的数据结构。该项目组织了四个主要研究项目：(A)在Linux内核和文件系统中添加对XRP的支持，(B)支持各种存储操作并与现实世界的存储系统集成，(C)加强内核内存储功能的服务质量、隔离和公平性，以及(D)实现对网络存储请求的内核内处理。快速存储设备将从根本上改变软件系统的构建方式，并需要重新设计支撑这些系统的整个存储堆栈。通过消除访问此类设备时的软件开销，同时保持操作系统支持，XRP将使系统能够实现高吞吐量和低且可预测的尾部延迟，同时保持Linux内核现有的隔离、安全和安全保证不变。立竿见影的好处将包括以更低的成本提供高性能的数据中心数据系统，这反过来将转化为为最终用户提供具有成本效益的云服务。软件产品将在开源许可下发布，以使其他研究人员能够与硬件和云提供商合作，将我们的研究转化为实践。项目库将通过首席调查员的网站获得：https://www.asafcidon.comThis奖反映了美国国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Emerging hardware storage devices can achieve millions of operations per second. They can also access data in as little as 2-3 microseconds, representing an order of magnitude improvement over legacy flash memory and hard disk technologies. However, at such low latencies, the overhead of the operating and file system becomes a significant bottleneck to end-to-end storage performance. Storage requests may slow down by 2x or more. The project designs XRP (eXpress Resubmission Path), a Linux-supported framework that allows applications to write storage functions that can be executed by the operating system. XRP allows applications to bypass almost entirely the overhead of the operating and file system. The main research challenge is that by bypassing the operating system’s storage layers, XRP lacks important context about the user’s request, such as who owns the block it is accessing, and how to traverse the application’s data structure safely and concurrently. The project organizes four primary research thrusts: (a) adding support for XRP in the Linux kernel and file system, (b) supporting a variety of storage operations and integrating with real-world storage systems, (c) enforcing quality of service, isolation and fairness of in-kernel storage functions, and (d) implementing in-kernel handling of over-the-network storage requests. Fast storage devices will fundamentally change the way software systems are built, and will require a redesign of the entire storage stack underpinning these systems. By eliminating the software overhead when accessing such devices, while maintaining operating system support, XRP will enable systems to achieve both high throughput and low and predictable tail latency, while leaving intact the existing isolation, security and safety guarantees of the Linux kernel. The immediate benefits will include high-performing datacenter data systems at a reduced cost, which will in turn translate to cost-effective cloud services for end users. Software artifacts will be released under open-source licenses to enable other researchers, and work with hardware and cloud providers to transition our research into practice. The project repository will be available via the principal investigator’s website: https://www.asafcidon.comThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.