Performance Exploration of Software-based Packet Processing Systems

Software systems that are placed on commodity hardware are integral components of today’s networks. They gain momentum as an attractive alternative to dedicated hardware routers, switches, and firewalls. Their big advantages are the high customizability of the software and increased cost-efficiency of the necessary hardware. To improve the performance, features intended to speed up the processing, are steadily added. For assessing influences on the performance, the software and its interaction with available hardware features have to be tested and modelled. Therefore, we evaluate the performance of the Linux Network Stack in different use cases and develop a performance prediction model. Using both blackand whitebox measurements the internal behaviour of the Linux router is analysed when approaching data rates up to 10 Gbit/s and the impact of occurring performance limiting factors is studied. External measurements are restricted to the packet rate, while white-box measurements are performed using the profiling tool perf. From the results of these measurements, the CPU cycles required to process each packet and their distribution to the tasks executed by the involved driver and kernel functions is analysed.