Performances of the ATLAS RPC first level Muon trigger during the Run-II data taking

The fist level (L1) muon barrel trigger is one of the main elements of the event selection of the ATLAS experiment at the Large Hadron Collider. Its input is made of an array of processors which receive the full granularity of data from Resistive Plate Chambers (RPC) in the central ("Barrel") area of the ATLAS detector. The Barrel RPCs are arranged in three concentric double layers and operate in a strong toroidal magnetic field. The RPC detectors cover the pseudo-rapidity range $ | \eta |< $1.05 for a total surface of more than 4000 $m^2$ and about 3600 gas volumes. The L1 Muon Trigger in the barrel region allows to select muon candidates with respect to their transverse momentum and associate them to the correct bunch-crossing number. We present the performance of the L1 muon trigger during the LHC Run-2 data taking