Event building at multi-kHz rates: lessons learned from the PHENIX event builder

The PHENIX experiment is one of four located at BNL´s Relativistic Heavy Ion Collider (RHIC). It is a high rate, large data volume detector, consisting of 14 detector subsystems. The PHENIX DAQ is a highly-pipelined parallel system. Central to the DAQ back-end is the PHENIX Event Builder (EvB). Since the start of RHIC in 2000, the EvB has undergone steady evolution towards the goal of archiving at multiple kHz event rates. The most recent major development towards the goal of 5 kHz archiving rate for Run5 was the migration of the Event Builder from Win32 to Linux. The current status of the PHENIX Event builder is presented with a focus on the lessons learned in the process. The transition to Linux is discussed, comparing the issues and performance to the previous implementation on Win32