LHCb D ata P rocessing S oftware J. Blouw, A. Zhelezov Physikalisches Institut, Universitaet Heidelberg DESY Computing Seminar, Nov. 29th, 2010

2/2/Contents The LHCb experiment Context Framework Design Online Offline Results

3/3/ The LHCb experiment & performance

4/4/ Excellent performance of LHC! Excellent start of data taking! Collected Integrated & and recorded luminosity:Data taking efficiency vs. run number:

5/5/ Context: data volume/flow Use of the framework during operations: Data rate O(100 MB)/s ⇒ online requirements Onlin e Offlin e

6/6/ Context: data volume/flow Use of the framework during operations: Data rate O(100 MB)/s ⇒ online requirements This year: O(20 TB) of raw data Including dst’s and physics streams: O(700) TB Onlin e Offlin e

7/7/ Context: data volume/flow Use of the framework during operations: Data rate O(100 MB)/s ⇒ online requirements This year: O(20 TB) of raw data Including dst’s and physics streams: O(700) TB ⇒ offline requirements Onlin e Offlin e

8/8/ The LHCb Software Framework implemented in C++ Separation between data and algorithms Separation between persistent and transient data Useful for developing applications in HEP Run in different environments (trigger applications, track reconstruction) Useful both online & offline The ’baby’ is called: Gaudi.

9/9/Gaudi

10/Gaudi transient data: lifetime for duration of process algorithms read/write data objects from transient data stores buffer for data conversion has unix, tree-like structure

11/ Gaudi transient data: lifetime for duration of process algorithms read/write data objects from transient data stores buffer for data conversion has unix, tree-like structure persistent data: “Converters” convert transient data in persistent data and vice versa different persistency technologies depending on access pattern

12/Gaudi transient data: lifetime for duration of process algorithms read/write data objects from transient data stores buffer for data conversion has unix, tree-like structure persistent data: “Converters” convert transient data in persistent data and vice versa different persistency technologies depending on access pattern services MessageSvc: verbosity level of output Job option service: configuration of user algorithms persistency services: input/output of data other services...

13/ Online: Trigger Reminder: dataflow

14/ Online: Trigger Scheme

15/ Online: Trigger Performance Efficiency: ε = 98% from Offline reconstruction Resolution: ∼ 3%

16/ Online: Trigger

17/ Online: Track-based Monitoring Schematic

18/ Online: Track-based Monitoring Online Track Reconstruction

19/ Online: Track-based Monitoring Monitoring

20/ Online: Track-based Monitoring Presenter

21/ Online: Conclusions Gaudi succesfully used: in software trigger (HLT) in monitoring software for development of LHCb software (simulation, reconstruction) by the Atlas experiment...

22/ Offline processing tasks Steered by dedicated Production Team Data distribution (T0->T1) Reconstruction + Stripping (T0/1) RAW -> rDST rDST -> DST (streams) Monte Carlo production (T2) Data replication (T0/1->T0/1) Steered by individual users Analysis (T0/T1) DST -> Tuples/Histograms

23/ Storage Offline Data Flow Ta pe CERN (T0) CERN (T0) LHC b Disc RAW data (T2) Monte Carlo DST Histograms/Tuples rDST GridK a (T1) CNAF (T1) NIKH EF (T1) PIC (T1) IN2P3 (T1) RAL (T1)

24/ Production Management System Workload Management System Data Management System

25/DIRAC ● Distributed Infrastructure with Remote Agent Control ● Python based daemons written within common framework ● Services: Configuration, Bookkeeping, Accounting, etc. ● Agents: Monitoring, Transformation, Production tracking, etc. ● Common web interface ● 200+ command line utilities ● No longer LHCb specific

26/ Production Request System

27/ Production Monitoring Separate request and production monitoring Easy navigation down to the job level

28/Accounting Jobs, pilots and data transfers history with different granularity and selection criteria

29/ User jobs Unpredictable nature Less tested applications Strict deadline (conference) Several approaches DIRAC API GANGA + DIRAC backend GANGA + batch system backend

30/ GANGA for LHCb G PI GUI CLI P Scri pt Application plugins Gaudi Brunel DaVinci... GANGA Core Backends DIRAC Batch Local LHCBDataset

31/ LHCb Bookkeeping Part of DIRAC Oracle DB based 3 user interfaces DIRAC Web Portal GUI Command line

32/ DIRAC job monitoring Progress Parameters Failure analysis

33/ Not in GRID Reasons Development Not standard software Reliability Problems Software model: lxplus/CERN batch only How to get the data? How to install the software?

34/ Localized resources Local farm (PI HD) NAF (DESY ZN)

35/ Website to support users

36/ Data and software manager The same interface for local farm and NAF

37/ Personal “Computer Center” Reason LHCb core software “prefer” SL(C) 4/5/(6) Modern desktops/notebooks “prefer” Ubuntu/SUSE Solution: “chroot” virtualization No resource penalties Several systems in parallel without RAM multiplication Zero processing speed degradation Easy to deploy 3 years without any problem (Debian/Ubuntu hosts)

38/ Some results & Conclusions CP violation in Bs system is the main program for LHCb Prerequisites: oscillation frequency of Bs mixing known Use Bs → KK and Bd → ππ to resolve ambiguity

39/ Some results & Conclusions CP violation in Bs system is the main program for LHCb Prerequisites: oscillation frequency of Bs mixing known Use Bs → KK and Bd → ππ to resolve ambiguity Bs → J/Ψφ signal with 1/20 of this years data

40/ Some results & Conclusions CP violation in Bs system is the main program for LHCb Prerequisites: oscillation frequency of Bs mixing known Use Bs → KK and Bd → ππ to resolve ambiguity Bs → J/Ψφ signal with 1/20 of this years data Oscillations in Bd → D ∗ lν already seen! Expect competitive measurement with 2010 data!

41/ Some results & Conclusions CP violation in Bs system is the main program for LHCb Prerequisites: oscillation frequency of Bs mixing known Use Bs → KK and Bd → ππ to resolve ambiguity Bs → J/Ψφ signal with 1/20 of this years data Oscillations in Bd → D ∗ lν already seen! Expect competitive measurement with 2010 data! Glimpse of CP in Bd → Kπ

42/Conclusion Already published physics papers and numerous talks have proven that our data processing software and tools are capable of doing the job. We are looking forward for many exciting discoveries in the next years.