21-25 May 2012
New York City, NY, USA
US/Eastern timezone

The CMS High Level Trigger System: Experience and Future Development

24 May 2012, 13:30
4h 45m
Rosenthal Pavilion (10th floor) (Kimmel Center)

Rosenthal Pavilion (10th floor)

Kimmel Center

Poster Online Computing (track 1) Poster Session


Andrei Cristian Spataru (CERN)


The CMS experiment at the LHC features a two-level trigger system. Events accepted by the first level trigger, at a maximum rate of 100 kHz, are read out by the Data Acquisition system (DAQ), and subsequently assembled in memory in a farm of computers running a software high-level trigger (HLT), which selects interesting events for offline storage and analysis at a rate of order few hundred Hz. The HLT algorithms consist of sequences of offline-style reconstruction and filtering modules, executed on a farm of 0(10000) CPU cores built from commodity hardware. Experience from the operation of the HLT system in the collider run 2010/2011 is reported. The current architecture of the CMS HLT, its integration with the CMS reconstruction framework and the CMS DAQ, are discussed in the light of future development. The possible short- and medium-term evolution of the HLT software infrastructure to support extensions of the HLT computing power, and to address remaining performance and maintenance issues, are discussed.

Primary author


Mr Alexander Flossdorf (DESY) Andre Georg Holzner (Univ. of California San Diego (US)) Andrea Petrucci (CERN) Dr Attila Racz (CERN) Aymeric Arnaud Dupont (CERN) Christian Deldicque (CERN) Christian Hartl (CERN) Christoph Paus (Massachusetts Inst. of Technology (US)) Christoph Schwick (CERN) Dennis Shpakov (Fermi National Accelerator Lab. (US)) Dominique Gigi (CERN) Emilio Meschi (CERN) Frank Glege (CERN) Frans Meijers (CERN) Gerry Bauer (Massachusetts Inst. of Technology (US)) Dr Giovanni Polese (CERN) Hannes Sakulin (CERN) James Branson (Univ. of California San Diego (US)) Dr Jeroen Hegeman (CERN) Dr Jose Antonio Coarasa Perez (CERN) Konstanty Sumorok (Massachusetts Inst. of Technology (US)) Lorenzo Masetti (CERN) Luciano Orsini (CERN) Dr Marc Dobson (CERN) Marco Pieri (Univ. of California San Diego (US)) Matteo Sani (Univ. of California San Diego (US)) Matthew Bowen (University of the West of England) Michal Simon Olivier Raginel (Massachusetts Inst. of Technology (US)) Remi Mommsen (Fermi National Accelerator Lab. (US)) Robert Gomez-Reino Garrido (CERN) Samim Erhan (Univ. of California Los Angeles (US)) Sebastian Bukowiec (CERN) Sergio Cittolin (Univ. of California San Diego (US)) Ulf Behrens (Deutsches Elektronen-Synchrotron (DE)) Vivian O'Dell (Fermi National Accelerator Laboratory (FNAL)) Yi Ling Hwong (CERN)

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