Optimizing Network I/O Virtualization with Efficient Interrupt Coalescing and Virtual Receive Side Scaling

Abstract

Virtualization is a fundamental component in cloud computing because it provides numerous guest VM transparent services, such as live migration, high availability, rapid checkpoint, etc. However, I/O virtualization, particularly for network, is still suffering from significant performance degradation. In this paper, we analyze performance challenges in network I/O virtualization and observe that the conventional network I/O virtualization incurs excessive virtual interrupts to guest VMs, and the backend driver in the driver domain is not parallelized and cannot leverage underlying multi-core processors. Motivated by the above observations, we propose optimizations: efficient interrupt coalescing for network I/O virtualization and virtual receive side scaling to effectively leverage multi-core processors. We implemented those optimizations in Xen and did extensive performance evaluation. Our experimental results reveal that the proposed optimizations significantly improve network I/O virtualization performance and effectively tackle the performance challenges.