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Prototype of a File-Based High-Level Trigger in CMS

Bauer, G.; Morović, Srećko; Zejdl, P. (2014) Prototype of a File-Based High-Level Trigger in CMS. Journal of Physics: Conference Series, 513 . 012025/1-012025/5. ISSN 1742-6588

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The DAQ system of the CMS experiment at the LHC is upgraded during the accelerator shutdown in 2013/14. To reduce the interdependency of the DAQ system and the high-level trigger (HLT), we investigate the feasibility of using a file- system-based HLT. Events of ~1 MB size are built at the level-1 trigger rate of 100 kHz. The events are assembled by ~50 builder units (BUs). Each BU writes the raw events at ~2GB/s to a local file system shared with Q(10) filter-unit machines (FUs) running the HLT code. The FUs read the raw data from the file system, select Q(1%) of the events, and write the selected events together with monitoring meta-data back to a disk. This data is then aggregated over several steps and made available for offline reconstruction and online monitoring. We present the challenges, technical choices, and performance figures from the prototyping phase. In addition, the steps to the final system implementation will be discussed.

Item Type: Article
Additional Information: Rad je predstavljen na 20th International Conference on Computing in High Energy and Nuclear Physics (CHEP2013).
Uncontrolled Keywords: DAQ system; CMS experiment; LHC
Subjects: NATURAL SCIENCES > Physics
Divisions: Division of Experimental Physics
Depositing User: Srećko Morović
Date Deposited: 26 Aug 2016 14:12
DOI: 10.1088/1742-6596/513/1/012025

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