LHCb - Commissioning of the LHCb’s first level trigger

The LHCb’s Upgrade 1 aims to record 25 $fb^{-1}$ in Run3-4 with an increased luminosity of $2 \times 10^{33} cm^{-2} s^{-1}$, a factor 5 compared to Run1-2. The upgrade features a completely new DAQ system with a full software trigger. The reconstruction of events is performed at 30 MHz LHC non-empty pp collision rate, with around 5 TB/s of input data. To cope with this very high amount of input, the first high level trigger (HLT1) is fully based on Graphics Processing Units (GPU) in order to exploit their parallelisation power and achieve an output rate of 1 MHz. The poster presents the first year of the HLT1 commissioning with its many achievements.