CMS strategy for HPC resource exploitation

Abstract

High Energy Physics (HEP) experiments will enter a new era with the start of the HL-LHC program, with computing needs surpassing by large factors the current capacities. Anticipating such scenario, funding agencies from participating countries are encouraging the experimental collaborations to consider the rapidly developing High Performance Computing (HPC) international infrastructures to satisfy at least a fraction of the foreseen HEP processing demands. These HPC systems are highly non-standard facilities, custom-built for use cases largely different from HEP demands, namely the processing of particle collisions (real or simulated) which can be analyzed individually without correlation. The access and utilization of these systems by HEP experiments will not be trivial, given the diversity of configuration and requirements for access among HPC centers, increasing the level of complexity from the HEP experiment integration and operations perspectives. Additionally, while HEP data is residing on a distributed highly-interconnected storage infrastructure, HPC systems are in general not meant for accessing large data volumes residing outside the facility. Finally, the allocation policies to these resources are generally different from the current usage of pledged resources deployed at supporting Grid sites. This report covers the CMS strategy developed to make effective use of HPC resources, involving a closer collaboration between CMS and HPC centers in order to further understand and subsequently overcome the present obstacles. Progress in the necessary technical and operational adaptations being made in CMS computing is described.