Performance of the ATLAS track and vertex reconstruction 
in the LHC Run 2

Run-2 of the LHC has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity environments and boosted, highly-collimated physics objects. The Insertable B-layer (IBL) is a fourth pixel layer, which was inserted in the innermost region of ATLAS during the long shutdown of the LHC. We will present results showing the performance of the track and vertex reconstruction algorithms using Run-2 data at the LHC and discuss some of the challenges encountered during commissioning. Recent improvements include a factor of three reduction in the reconstruction time, optimisation for the expected conditions, novel techniques to enhance the performance in dense jet cores and time-dependent alignment of sub-detectors. Moreover, data-driven methods to evaluate vertex resolution, fake rates, track reconstruction inefficiencies in dense environments, and track parameter resolution and biases will be shown.