A study of network stack latency for game servers

Latency has a high impact on the user satisfaction in real-time multiplayer games. The network between the client and server is, in most cases, the main cause for latency and out of the scope of the game's developer. But the developer should avoid introducing unnecessary delays within his responsibility; i.e. with respect to development and operating costs he should wisely choose a network stack and deployment model for the server in order to reduce latency. In this paper we present latency measurements of the Linux network stack and effects of virtualization. We show that a worst-case scenario can cause a latency in the millisecond range when running a game server. We discuss how latencies can be reduced by using the packet processing framework DPDK to replace the operating system's network stack.