  The High-Luminosity upgrade of the LHC will see the accelerator reach an
instantaneous luminosity of $7\times 10^{34} cm^{-2}s^{-1}$ with an average
pileup of $200$ proton-proton collisions. These conditions will pose an
unprecedented challenge to the online and offline reconstruction software
developed by the experiments. The computational complexity will exceed by far
the expected increase in processing power for conventional CPUs, demanding an
alternative approach. Industry and High-Performance Computing (HPC) centres are
successfully using heterogeneous computing platforms to achieve higher
throughput and better energy efficiency by matching each job to the most
appropriate architecture. In this paper we will describe the results of a
heterogeneous implementation of pixel tracks and vertices reconstruction chain
on Graphics Processing Units (GPUs). The framework has been designed and
developed to be integrated in the CMS reconstruction software, CMSSW. The speed
up achieved by leveraging GPUs allows for more complex algorithms to be
executed, obtaining better physics output and a higher throughput.
