Experience with the alpaka performance portability library in the CMS software

EPJ Web of Conferences, vol. 337, pp. 01141

Abstract

To achieve better computational efficiency and exploit a wider range of computing resources, the CMS software framework (CMSSW) has been extended to offload part of the physics reconstruction to NVIDIA GPUs. To support additional back-ends, as well to avoid the need to write, validate and maintain a separate implementation of the reconstruction algorithms for each back-end, CMS has adopted the alpaka performance portability library. Alpaka (Abstraction Library for Parallel Kernel Acceleration) is a header-only C++ library that provides performance portability across different back-ends, abstracting the underlying levels of parallelism. It supports serial and parallel execution on CPUs, and extremely parallel execution on NVIDIA, AMD and Intel GPUs. This contribution will show how alpaka is used in the CMS software to develop and maintain a single code base; to use different toolchains to build the code for each supported back-end, and link them into a single application; to seamlessly select the best backend at runtime, and implement portable reconstruction algorithms that run efficiently on CPUs and GPUs from different vendors. It will describe the validation and deployment of the alpaka-based implementation in the CMS High Level Trigger, and highlight how it achieves near-native performance.

Authors 47

1. Jaafar Alawieh

   European Organization for Nuclear Research

   Affiliation as printed

   CERN, Geneva, Switzerland

2. Kareen Arutjunjan

   European Organization for Nuclear Research

   Affiliation as printed

   CERN, Geneva, Switzerland

3. Miguel Bacharov Durasov

   European Organization for Nuclear Research

   Affiliation as printed

   CERN, Geneva, Switzerland

4. U. Behrens

   Rice University

   Affiliation as printed

   Rice University, Houston, Texas, USA

5. Andrea Bocci

   European Organization for Nuclear Research

   Affiliation as printed

   CERN, Geneva, Switzerland

6. James G. Branson

   University of California San Diego

   Affiliation as printed

   UCSD, San Diego, California, USA

7. Philipp Maximilian Brummer

   European Organization for Nuclear Research

   Affiliation as printed

   CERN, Geneva, Switzerland

8. Jan Andrzej Bugajski

   European Organization for Nuclear Research

   Affiliation as printed

   CERN, Geneva, Switzerland

9. Eric Cano

   European Organization for Nuclear Research

   Affiliation as printed

   CERN, Geneva, Switzerland

10. Sergio Cittolin

    University of California San Diego

    Affiliation as printed

    UCSD, San Diego, California, USA

11. Albert Corominas I Mariscot

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

12. Georgiana-Lavinia Darlea

    Massachusetts Institute of Technology

    Affiliation as printed

    MIT, Cambridge, Massachusetts, USA

13. Christian Deldicque

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

14. Marc Dobson

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

15. Antonı́n Dvořák

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

16. Christos Emmanouil

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

17. Antra Gaile

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

18. Dominique Gigi

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

19. Frank Glege

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

20. G. Gomez Ceballos

    Massachusetts Institute of Technology

    Affiliation as printed

    MIT, Cambridge, Massachusetts, USA

21. Patrycja Górniak

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

22. J. Hegeman

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

23. Guillermo Izquierdo Moreno

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

24. Thomas Owen James

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

25. Wassef Karimeh

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

26. M. J. Kortelainen

    Fermi National Accelerator Laboratory

    Affiliation as printed

    Fermilab, Batavia, Illinois, USA

27. R. D. Krawczyk

    Rice University

    Affiliation as printed

    Rice University, Houston, Texas, USA

28. Wei Li

    Rice University

    Affiliation as printed

    Rice University, Houston, Texas, USA

29. K. Long

    Massachusetts Institute of Technology

    Affiliation as printed

    MIT, Cambridge, Massachusetts, USA

30. Frans Meijers

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

31. Emilio Meschi

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

32. Srećko Morović

    University of California San Diego

    Affiliation as printed

    UCSD, San Diego, California, USA

33. Babatunde John Odetayo

    University of Benin · European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

    University of Benin, Benin City, Nigeria

34. Luciano Orsini

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

35. Christoph M. E. Paus

    Massachusetts Institute of Technology

    Affiliation as printed

    MIT, Cambridge, Massachusetts, USA

36. Andrea Petrucci

    University of California San Diego

    Affiliation as printed

    UCSD, San Diego, California, USA

37. M. Pieri

    University of California San Diego

    Affiliation as printed

    UCSD, San Diego, California, USA

38. Dinyar Sebastian Rabady

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

39. Attila Racz

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

40. W. Redjeb Aachen

    European Organization for Nuclear Research · RWTH Aachen University

    Affiliation as printed

    CERN, Geneva, Switzerland

    RWTH Aachen University, Aachen, Germany

41. Theodoros Rizopoulos

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

42. Hannes Sakulin

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

43. Christoph Schwick

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

44. Dainius Šimelevičius

    Vilnius University · European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

    Vilnius University, Vilnius, Lithuania

45. Polyneikis Tzanis

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

46. Cristina Vazquez Velez

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland

47. Petr Zejdl

    European Organization for Nuclear Research

    Affiliation as printed

    CERN, Geneva, Switzerland