Evaluating Performance Portability with the CMS Heterogeneous Pixel Reconstruction code

Abstract

CMS uses GPUs as part of the High-Level Trigger farm in LHC Run 3 • GPU vendors provide their own APIs that also differ from programming the CPU -Want to minimize development and maintenance effort -CMS is moving to have portable code between CPU and NVIDIA and AMD GPUs via Alpaka • Want to be aware of the other technologies in the market to guide long term planning • Used CMS heterogeneous pixel reconstruction (Patatrack) as a use case for a set of realistic algorithms utilizing GPU effectively • Measure the performance of direct, Alpaka, Kokkos, and SYCL versions on CPU, NVIDIA GPU, and AMD GPU -All versions give the same results (within reproducibility accuracy) -Some grain of salt needed to interpret the results• The versions using different portability technologies have differences• Report initial experience with std::par and OpenMP Target offload

Authors 14

1. Nikolaos Andriotis
   Affiliation as printed

   Unlisted

2. Andrea Bocci

   European Organization for Nuclear Research

   Affiliation as printed

   CERN

3. Eric Cano

   European Organization for Nuclear Research

   Affiliation as printed

   CERN

4. Laura Cappelli

   Istituto Nazionale di Fisica Nucleare · Istituto Nazionale di Fisica Nucleare, Sezione di Bologna · University of Bologna

   Affiliation as printed

   INFN, Bologna; U. Bologna, DIFA

   INFN, Bologna

5. Mark Dewing

   Argonne National Laboratory

   Affiliation as printed

   Argonne

6. Tony Di Pilato

   University of Geneva · Center for Advanced Systems Understanding

   Affiliation as printed

   CASUS; Geneva U

   CASUS

7. Julien Esseiva

   Lawrence Berkeley National Laboratory

   Affiliation as printed

   LBL, Berkeley

8. Gabrielle Hugo

   European Organization for Nuclear Research

   Affiliation as printed

   CERN

9. M. J. Kortelainen

   Fermi National Accelerator Laboratory

   Affiliation as printed

   Fermilab

10. M. Kwok

    Fermi National Accelerator Laboratory

    Affiliation as printed

    Fermilab

11. Juan Jose Olivera Loyola

    Instituto Politécnico Nacional · Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional

    Affiliation as printed

    CINVESTAV, IPN

12. Felice Pantaleo

    European Organization for Nuclear Research

    Affiliation as printed

    CERN

13. Albino Perego

    Istituto Nazionale di Fisica Nucleare, Sezione di Milano · Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca

    Affiliation as printed

    INFN, Milan; Milan Bicocca U

    INFN, Milan

14. W. Redjeb Aachen

    European Organization for Nuclear Research · RWTH Aachen University

    Affiliation as printed

    CERN; RWTH Aachen U