International Science Index


The DAQ Debugger for iFDAQ of the COMPASS Experiment

Abstract:In general, state-of-the-art Data Acquisition Systems (DAQ) in high energy physics experiments must satisfy high requirements in terms of reliability, efficiency and data rate capability. This paper presents the development and deployment of a debugging tool named DAQ Debugger for the intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN. Utilizing a hardware event builder, the iFDAQ is designed to be able to readout data at the average maximum rate of 1.5 GB/s of the experiment. In complex softwares, such as the iFDAQ, having thousands of lines of code, the debugging process is absolutely essential to reveal all software issues. Unfortunately, conventional debugging of the iFDAQ is not possible during the real data taking. The DAQ Debugger is a tool for identifying a problem, isolating the source of the problem, and then either correcting the problem or determining a way to work around it. It provides the layer for an easy integration to any process and has no impact on the process performance. Based on handling of system signals, the DAQ Debugger represents an alternative to conventional debuggers provided by most integrated development environments. Whenever problem occurs, it generates reports containing all necessary information important for a deeper investigation and analysis. The DAQ Debugger was fully incorporated to all processes in the iFDAQ during the run 2016. It helped to reveal remaining software issues and improved significantly the stability of the system in comparison with the previous run. In the paper, we present the DAQ Debugger from several insights and discuss it in a detailed way.
[1] P. Abbon, et al.(the COMPASS collaboration): The COMPASS experiment at CERN. In: Nucl. Instrum. Methods Phys. Res., A 577, 3 (2007) pp. 455518.
[2] V. Y. Alexakhin, et al. (the COMPASS Collaboration): COMPASS-II Proposal. CERN-SPSC-2010-014, SPSC-P-340. May 2010.
[3] B. Grube: A Trigger Control System for COMPASS and a Measurement of the Transverse Polarization of Lambda and Xi Hyperons from Quasi-Real Photo-Production.. Munich. Technical University Munich. 2006. Doctoral thesis.
[4] Y. Bai, et al.: The Communication Library DIALOG for iFDAQ of the COMPASS experiment. 19th International Conference on High Energy Physics – ICHEP 2017, Paris, France, September 2017. International Journal of Mathematical, Computational, Physical, Electrical and Computer Engineering, vol. 11, issue 9, pp. 353-362, World Academy of Science, Engineering and Technology.
[5] T. Anticic, et al. (ALICE DAQ Project): ALICE DAQ and ECS User’s Guide CERN, EDMS 616039, January 2006.
[6] Debugging definition. (online). Available at: http://searchsoftwarequality. (Accessed: 2017-09-01).
[7] T. Gr¨otker, et al.: The Developer’s Guide to Debugging. Second Edition, Createspace, 2012. ISBN 1-4701-8552-0.
[8] G. J. Myers: The Art of Software Testing. John Wiley & Sons inc, 2004. ISBN 0-471-04328-1.
[9] M. Bodlak, et al.: Developing Control and Monitoring Software for the Data Acquisition System of the COMPASS Experiment at CERN. Acta polytechnica: Scientific Journal of the Czech Technical University in Prague. Prague, CTU, 2013, issue 4. Available at:
[10] M. Bodlak, et al.: Development of new data acquisition system for COMPASS experiment. Nuclear and Particle Physics Proceedings, 37th International Conference on High Energy Physics (ICHEP). AprilJune 2016, vol. 273275, pp. 976981. Available at: j.nuclphysbps.2015.09.153.
[11] M. Bodlak, et al.: FPGA based data acquisition system for COMPASS experiment. Journal of Physics: Conference Series. 2014-06-11, vol. 513, issue 1, s. 012029-. DOI: 10.1088/1742-6596/513/1/012029. Available at: crossref.78788d23de2b4a6a34d127c361123b8c.
[12] M. Bodlak, et al.: New data acquisition system for the COMPASS experiment. Journal of Instrumentation. 2013-02-01, vol. 8, issue 02, C02009-C02009. DOI: 10.1088/1748-0221/8/02/C02009. Available at: a76044facdf29d0fb21f9eefe3305aa5.
[13] C. Ghabrous Larrea, et al.: IPbus: a flexible Ethernet-based control system for xTCA hardware, 2015 JINST 10 C02019. doi:10.1088/1748-0221/10/02/C02019.
[14] CASTOR – CERN Advanced Storage manager. Available at: http: //
[Accessed: 2017-05-01]
[15] Electronic developments for COMPASS at Freiburg. Available at: http: // (Accessed: 2017-05-01).
[16] The GANDALF Module. (online). Available at: http://hpfr03.physik. (Accessed: 2017-05-01).
[17] iMUX/HGESICA module. (online). Available at: twiki/pub/Compass/Detectors/FrontEndElectronics/imux\ manual.pdf. (Accessed: 2017-05-01).
[18] Linux at CERN. (online). Available at: scientific6/. (Accessed: 2017-05-01).
[19] S-Link – High Speed Interconnect. (online). Available at: http://hsi.web. (Accessed: 2017-05-01).
[20] POSIX – Standards. IEEE. (online). Available at: org/develop/wg/POSIX.html. (Accessed: 2017-09-20).