Optimization of event-building implementation on top of gigabit Ethernet

LHCb is implementing event-building over a gigabit Ethernet switched network. One component of the data acquisition network is a gateway PC which role is to gather data packets from data sources, rebuild events and forward them to computing nodes for trigger algorithms. In this article, we concentrate on the implementation of this component as a software running on a Linux system. We describe in details implementation choices and details of the operating system kernel which permitted us to achieve a higher performance and ensure a higher predictability of the system