Performance Analysis of Large Receive Offload in a Xen Virtualized System

System-level virtualization provides us various advantages including independent and isolated computing environments on which multiple operating systems can be executed, and improved resource utilization. These benefits come with performance overheads and network operation is one of most typical cases. In this paper, we first present the experimental results of network performance with LRO under varying message sizes and maximum transmission unit (MTU). We analyze the effectiveness of large receive offload (LRO) in a consolidated execution environment based on Xen. When SPECjbb, a CPU-intensive workload, and network receiver are executed on separated domains, LRO in physical and virtual NICs improve the throughput up to 8 and 14%, respectively.