Segment Linking: A Highly Parallelizable Track Reconstruction Algorithm for HL-LHC

P. Chang, P. Elmer, Y. Gu, V. Krutelyov, G. Niendorf, M. Reid, B. V. Sathia Narayanan, M. Tadel, E. Vourliotis, B. Wang, P. Wittich, A. Yagil

Research output: Contribution to journalConference articlepeer-review


The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will produce particle collisions with up to 200 simultaneous proton-proton interactions. These unprecedented conditions will create a combinatorial complexity for charged-particle track reconstruction that demands a computational cost that is expected to surpass the projected computing budget using conventional CPUs. Motivated by this and taking into account the prevalence of heterogeneous computing in cutting-edge High Performance Computing centers, we propose an efficient, fast and highly parallelizable bottom-up approach to track reconstruction for the HL-LHC, along with an associated implementation on GPUs, in the context of the Phase 2 CMS outer tracker. Our algorithm, called Segment Linking (or Line Segment Tracking), takes advantage of localized track stub creation, combining individual stubs to progressively form higher level objects that are subject to kinematical and geometrical requirements compatible with genuine physics tracks. The local nature of the algorithm makes it ideal for parallelization under the Single Instruction, Multiple Data paradigm, as hundreds of objects can be built simultaneously. The computing and physics performance of the algorithm has been tested on an NVIDIA Tesla V100 GPU, already yielding efficiency and timing measurements that are on par with the latest, multi-CPU versions of existing CMS tracking algorithms.

Original languageEnglish (US)
Article number012005
JournalJournal of Physics: Conference Series
Issue number1
StatePublished - 2022
Event39th Conference on Recent Developments on High Energy Physics and Cosmology, HEP 2022 - Thessaloniki, Greece
Duration: Jun 15 2022Jun 18 2022

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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