Data Handling In The Alice O2 Event Processing
CERN,Route de Meyrin,
2 University of Oslo, Department of Physics, Postboks 1048 Blindern, 0316 Oslo, Norway
3 Frankfurt Institute for Advances Studies, Johann Wolfgang Goethe-Universität Frankfurt,Ruth-Moufang-Straße 1, 60483 Frankfurt, Germany
* e-mail: Matthias.Richter@cern.ch
Published online: 17 September 2019
The ALICE experiment at the Large Hadron Collider (LHC) at CERN is planned to be operated in a continuous data-taking mode in Run 3. This will allow to inspect data from all Pb-Pb collisions at a rate of 50 kHz, giving access to rare physics signals embedded in a large background.
Based on experience with real-time reconstruction of particle trajectories and event properties in the ALICE High Level Trigger, the ALICE O2 facility is currently designed and developed to support processing of a continuous, triggerless stream of data segmented into entities referred to as timeframes.
Both raw data input into the ALICE O2 system and the actual processing of aggregated timeframes are distributed among multiple processes on a manynode cluster. Process communication is based on the asynchronous message passing paradigm.
This paper presents the basic concept for identification of data in the distributed system together with prototype implementations and performance measurements.
© The Authors, published by EDP Sciences, 2019
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.