Large-Scale DAQ Tests for the LHCb Upgrade

To increase the event yield, the LHCb experiment will undergo a major detector upgrade planned during the second long shutdown of the Large Hadron Collider (2019-2020). The new data acquisition has to process the whole 40-MHz input event rate, relying only on the large-scale computing farm implementation of the high-level trigger. Event fragments will be forwarded at 40 MHz from the detector front-end electronics to the event builder (EB), through optical links and peripheral component interconnect express cards. The EB farm, of about 500 computers, shall provide an aggregated throughput of 32 Tb/s. To reach the required EB performance, we are testing various interconnect technologies and network protocols on large-scale computing clusters. For this purpose, we have developed an EB software evaluator. We report here about the results of the measurements performed on high-performance computing facilities to test throughput and scalability.