Preparing ATLAS reconstruction software for LHC's Run 2

In order to maximize the physics potential of the ATLAS detector during LHC's Run 2, the reconstruction software has been updated. Flat computing budgets required a factor of three improved run time, while the new xAOD data format forced changes in the reconstruction algorithms. Physics performance improvements have been made in the reconstruction of various objects, using improved techniques like multivariate discriminants, etc. This paper will present an overview of the improvements that have been made.