Integrating LHCb Offline Workflows on Supercomputers State of Practice.

To better understand experimental conditions and performances of its experiment, the LHCb collaboration executes tens of thousands of looselycoupled and CPU-intensive Monte Carlo simulation workflows per hour. To meet the increasing LHC computing needs, funding agencies encourage the collaboration to exploit High-Performance Computing resources, and more specifically supercomputers, which offer a significant additional amount of computing resources but also come with higher integration challenges. This state-ofpractice paper outlines years of integration of LHCb simulation workflows on several supercomputers. The main contributions of this paper are: (i) an extensive description of the gap to address to run High-Energy Physics Monte Carlo simulation workflows on supercomputers; (ii) various methods and proposals to maximize the use of allocated CPU resources; (iii) a comprehensive analysis of LHCb production workflows running on diverse supercomputers. [ABSTRACT FROM AUTHOR]