High performance networking interface cards (NIC) have become essential networking devices in commercial cloud computing environments. Therefore, efficient and scalable I/O virtualization is one of the primary challenges on virtualized cloud computing platforms. Single Root I/O Virtualization (SR-IOV) is a network interface technology that eliminates the overhead of redundant data copies and the virtual network switches through direct I/O in order to achieve nearly natural I/O performance. However, the SR-IOV still suffers from serious problems due to the high overhead for processing excessive network interrupts as well as the unpredictable and bursty traffic load in high-speed networking connections. In this paper, the defects of SR-IOV with 10 Gigabit Ethernet networking are studied first and two major challenges are identified: excessive interrupt rate and single threaded virtual network driver. Second, two interrupt rate control optimization schemes, called coarse-grained interrupt rate (CGR) control and adaptive interrupt rate (AIR) control are proposed. The proposed control schemes can significantly reduce the overhead and enhance the SR-IOV performance compared with the traditional driver with fixed interrupt throttle rate (FIR). In addition, multi-threaded VF driver (MTVD) is proposed that allows the SR-IOV VFs to leverage multi-core resources in order to achieve high scalability. Finally, these optimizations are implemented and detailed performance evaluations are conducted. The results show that CGR and AIR can improve the throughput by 2.26x and 2.97x while saving the CPU resources by 1.23 core and 1.44 core, respectively. The MTVD can achieve 2.03x performance with additional 1.46 cores consumption for VM using the SR-IOV driver.

中文翻译：

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当 I/O 中断成为系统瓶颈：SR-IOV 网络虚拟化的效率和可扩展性增强

高性能网络接口卡 (NIC) 已成为商业云计算环境中必不可少的网络设备。因此，高效且可扩展的 I/O 虚拟化是虚拟化云计算平台的主要挑战之一。单根 I/O 虚拟化 (SR-IOV) 是一种网络接口技术，通过直接 I/O 消除冗余数据复制和虚拟网络切换的开销，以实现近乎自然的 I/O 性能。然而，由于处理过多网络中断的高开销以及高速网络连接中不可预测和突发的流量负载，SR-IOV仍然存在严重问题。在本文中，首先研究了具有 10 Gb 以太网组网的 SR-IOV 的缺陷，并确定了两个主要挑战：过高的中断率和单线程虚拟网络驱动程序。其次，提出了两种中断率控制优化方案，称为粗粒度中断率（CGR）控制和自适应中断率（AIR）控制。与具有固定中断节流率 (FIR) 的传统驱动程序相比，所提出的控制方案可以显着降低开销并提高 SR-IOV 性能。此外，还提出了多线程 VF 驱动程序 (MTVD)，允许 SR-IOV VF 利用多核资源以实现高可扩展性。最后，实施这些优化并进行详细的性能评估。结果表明，CGR 和 AIR 可以将吞吐量提高 2.26 倍和 2.97 倍，同时分别节省 1.23 核和 1.44 核的 CPU 资源。MTVD 可以达到 2。