Evaluating the impact of simultaneous multithreading on network servers using real hardware

This paper examines the performance of simultaneous multithreading (SMT) for network servers using actual hardware, multiple network server applications, and several workloads. Using three versions of the Intel Xeon processor with Hyper-Threading, we perform macroscopic analysis as well as microarchitectural measurements to understand the origins of the performance bottlenecks for SMT processors in these environments. The results of our evaluation suggest that the current SMT support in the Xeon is application and workload sensitive, and may not yield significant benefits for network servers. In general, we find that enabling SMT on real hardware usually produces only slight performance gains, and can sometimes lead to performance loss. In the uniprocessor case, previous studies appear to have neglected the OS overhead in switching from a uniprocessor kernel to an SMT-enabled kernel. The performance loss associated with such support is comparable to the gains provided by SMT. In th...

• Type: Conference
• Year: 2005
• Where: SIGMETRICS
• Authors: Yaoping Ruan, Vivek S. Pai, Erich M. Nahum, John M. Tracey
• Keywords: Network Servers, Performance, Performance Loss, SIGMETRICS 2005