The CMS Event-Builder System for LHC Run 3 (2021-23) /

Jean-Marc Andre; Ulf Behrens; James Branson; Philipp Brummer; Sergio Cittolin; Diego Da Silva Gomes; Georgiana-Lavinia Darlea; Christian Deldicque; Zeynep Demiragli; Marc Dobson; Nicolas Doualot; Samim Erhan; Jonathan Fulcher; Dominique Gigi; Maciej Gladki; Frank Glege; Guillelmo Gomez-Ceballos; Jeroen Hegeman; Andre Holzner; Michael Lettrich; Audrius Mečionis; Frans Meijers; Emilio Meschi; Remigius K Mommsen; Srecko Morovic; Vivian O'Dell; Luciano Orsini; Ioannis Papakrivopoulos; Christoph Paus; Andrea Petrucci; Marco Pieri; Dinyar Rabady; Attila Racz; Valdas Rapševičius; Thomas Reis; Hannes Sakulin; Christoph Schwick; Dainius Šimelevičius; Mantas Stankevičius; Cristina Vazquez Velez; Christian Wernet; Petr Zejdl

doi:10.1051/epjconf/201921401006

Title	The CMS Event-Builder System for LHC Run 3 (2021-23) /
Authors	Andre, Jean-Marc ; Behrens, Ulf ; Branson, James ; Brummer, Philipp ; Cittolin, Sergio ; Gomes, Diego Da Silva ; Darlea, Georgiana-Lavinia ; Deldicque, Christian ; Demiragli, Zeynep ; Dobson, Marc ; Doualot, Nicolas ; Erhan, Samim ; Fulcher, Jonathan ; Gigi, Dominique ; Gladki, Maciej ; Glege, Frank ; Gomez-Ceballos, Guillelmo ; Hegeman, Jeroen ; Holzner, Andre ; Lettrich, Michael ; Mečionis, Audrius ; Meijers, Frans ; Meschi, Emilio ; Mommsen, Remigius K ; Morovic, Srecko ; O'Dell, Vivian ; Orsini, Luciano ; Papakrivopoulos, Ioannis ; Paus, Christoph ; Petrucci, Andrea ; Pieri, Marco ; Rabady, Dinyar ; Racz, Attila ; Rapševičius, Valdas ; Reis, Thomas ; Sakulin, Hannes ; Schwick, Christoph ; Šimelevičius, Dainius ; Stankevičius, Mantas ; Velez, Cristina Vazquez ; Wernet, Christian ; Zejdl, Petr
DOI	10.1051/epjconf/201921401006
Full Text
Is Part of	23rd International Conference on Computing in High Energy and Nuclear Physics (CHEP 2018), Sofia, Bulgaria, July 09-13, 2018.. Les Ulis : EDP Sciences. 2019, art. no. 01006, p. [1-8]
Abstract [eng]	The data acquisition system (DAQ) of the CMS experiment at the CERN Large Hadron Collider (LHC) assembles events of 2MB at a rate of 100 kHz. The event builder collects event fragments from about 750 sources and assembles them into complete events which are then handed to the High-Level Trigger (HLT) processes running on O(1000) computers. The aging eventbuilding hardware will be replaced during the long shutdown 2 of the LHC taking place in 2019/20. The future data networks will be based on 100 Gb/s interconnects using Ethernet and Infiniband technologies. More powerful computers may allow to combine the currently separate functionality of the readout and builder units into a single I/O processor handling simultaneously 100 Gb/s of input and output traffic. It might be beneficial to preprocess data originating from specific detector parts or regions before handling it to generic HLT processors. Therefore, we will investigate how specialized coprocessors, e.g. GPUs, could be integrated into the event builder. We will present the envisioned changes to the event-builder compared to today’s system. Initial measurements of the performance of the data networks under the event-building traffic pattern will be shown. Implications of a folded network architecture for the event building and corresponding changes to the software implementation will be discussed.
Published	Les Ulis : EDP Sciences
Type	Conference paper
Language	English
Publication date	2019
CC license

„The CMS Event-Builder System for LHC Run 3 (2021-23) /“