CSR: Small: Core Scheduling to Improve Virtualized I/O Performance on Multi-Core Systems

该项目侧重于减少多核平台中网络处理的开销和增加吞吐量。特别是，分组处理功能建议在核心之间均衡，以便于下一代系统中的虚拟化。低成本的多核架构将许多CPU内核放在同一个芯片上，在今天的市场上随处可见。研究人员正在为不同的应用开发一系列编程技术，以有效地利用这种多核架构中的并行性。然而，关于如何缓解I/O瓶颈（协议处理开销占CPU执行时间的主要部分）的研究很少。多核使人们对虚拟化的各种用途产生了广泛的兴趣，包括服务器整合和各种资源的共享。研究表明，虚拟化给网络I/O带来了显著的额外开销。这个项目的目标是开发技术来优化高速网络下虚拟I/O的性能。特别是，研究小组探索了虚拟环境中的新软件技术，这些技术可以通过以下方法减少多核处理器中的网络I/O开销：包的生命周期分析：这涉及一种测量技术，用于在具有10千兆以太网的虚拟化环境中跟踪包的生命周期。研究仪器操作系统软件，并应揭示潜在的瓶颈功能，贡献很大的数据包延迟。2. 对协议栈进行多线程处理：基于数据包生命周期分析，客户机O/S和虚拟机监视器（VMM）中的TCP/IP协议栈将被划分为多个线程，这些线程可以在多个核心上并行执行并减少延迟。为了利用多核架构的缓存局部性，开发了核调度技术，将这些线程分配到不同的核上。3. 管道调度：不是根据延迟瓶颈拆分协议栈，而是根据代码大小和开发的多个线程对任务进行分区。开发了适当调度线程的技术，以减少缓存丢失。4. 虚拟化环境的联合调度：尽管并行/管道技术是与TCP/IP堆栈和VMM分开开发的，但它们结合在一起可以在虚拟环境中创建多个线程，并应用各种代码调度优化来减少延迟和增加I/O吞吐量。这里描述的一个免费项目部分得到了英特尔公司的资助。因此，该项目的研究成果可能具有很强的技术转移潜力。PI指导了几位后来在建筑研究方面声名鹊起的博士毕业生，他在过去两年中指导了四名女性博士毕业生，为增加女性在该国计算机领域的代表性做出了贡献。这些努力将在NSF项目下继续进行。UCR是公认的少数民族服务机构。因此，让本科生参与将使少数民族参与到项目中来。

This project focuses on reducing the overhead and increasing throughput of network processing in multi-core platforms. In particular, packet processing functions are proposed to be balanced across the cores so as to facilitate virtualization in next-generation systems.Low-cost multi-core architectures that put many CPU cores on the same chip are abundantly available in the market today. Researchers are developing a range of programming techniques for different applications to efficiently utilize the parallelism available in such multi-core architectures. However, research into how to alleviate the I/O bottleneck, where protocol-processing overhead dominates the CPU execution time, is sparse.Multicore has enabled broad interest in virtualization for diverse uses including server consolidation and sharing of various resources. Studies have shown that virtualization brings significant extra overhead to network I/O. The objective of this project is to develop techniques to optimize the performance of virtualized I/O with high-speed networks. In particular, the research team explores new software techniques in virtualized environments, that may reduce the network I/O overhead in multi-core processors, through the following approaches: 1. Life of a Packet Analysis: this involves a measurement technique to trace the life of a packet in a virtualized environment with 10 Gigabit Ethernet. The study instruments the OS software, and should reveal potential bottleneck functions that contribute heavily to packet latency. 2. Mutithreading the protocol stack: Based on life-of-a-packet analysis, the TCP/IP protocol stack in the guest O/S and virtual machine monitor (VMM) will be divided into multiple threads that can execute in parallel on multiple cores and cut down the latency. Core scheduling techniques are developed to allocate these threads to different cores so as to exploit the cache locality of the multi-core architecture. 3. Pipeline Scheduling: Instead of splitting the protocol stack in terms of latency bottleneck, tasks are partitioned based on code size and multiple threads developed. Techniques are developed to schedule the threads appropriately so that the cache misses are reduced. 4. Combined Scheduling for Virtualized Environment: Although the parallel/pipeline techniques are developed separately from the TCP/IP stack and VMM, they are combined to create multiple threads in a virtualized environment and various code scheduling optimizations are applied to reduce latency and increase I/O throughput. A complimentary project to the one described here has been partly supported by grants from the Intel Corporation. Hence, the research results obtained from this project may have strong potential for technology transfer. The PI has mentored several Ph.D. graduates who later developed reputations for architecture research and he has mentored four female Ph.D. graduates during the last two years, contributing to increasing the representation of women in computing in the country. Such efforts continue under this NSF project. UCR is recognized as a minority serving institution. Hence, involving undergraduate students will enable minority participation in the project.