LHCb trigger streams optimization

D. Derkach, N. Kazeev, R. Neychev, A. Panin, I. Trofimov, A. Ustyuzhanin, M. Vesterinen

Research output: Contribution to journalConference articlepeer-review

1 Citation (Scopus)


The LHCb experiment stores around 1011 collision events per year. A typical physics analysis deals with a final sample of up to 107 events. Event preselection algorithms (lines) are used for data reduction. Since the data are stored in a format that requires sequential access, the lines are grouped into several output file streams, in order to increase the efficiency of user analysis jobs that read these data. The scheme efficiency heavily depends on the stream composition. By putting similar lines together and balancing the stream sizes it is possible to reduce the overhead. We present a method for finding an optimal stream composition. The method is applied to a part of the LHCb data (Turbo stream) on the stage where it is prepared for user physics analysis. This results in an expected improvement of 15% in the speed of user analysis jobs, and will be applied on data to be recorded in 2017.

Original languageEnglish
Article number062026
JournalJournal of Physics: Conference Series
Issue number6
Publication statusPublished - 23 Nov 2017
Externally publishedYes
Event22nd International Conference on Computing in High Energy and Nuclear Physics, CHEP 2016 - San Francisco, United States
Duration: 10 Oct 201614 Oct 2016


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