Performance of Run 3 track reconstruction with the mkFit algorithm

This note reports on the CMS track reconstruction at the LHC Run 3. In Run 2, the CMS track reconstruction algorithm used an iterative approach based on combinatorial Kalman Filter (CKF). For Run 3, a new algorithm has been developed for track pattern recognition, named mkFit, that maximally exploits parallelization and vectorization in multi-core CPU architectures. This algorithm has been deployed in the CMS software for a subset of tracking iterations. The mkFit algorithm allows to retain a similar physics performance with respect to the traditional CKF-based pattern recognition, while improving the computational performance of the CMS track reconstruction. The content of this note is also available at: twiki.cern.ch/twiki/bin/view/CMSPublic/TRKmkFitRun3