1. 05/09/2001ATLAS UK Physics Meeting Data Challenge Needs RWL Jones

2. 05/09/2001ATLAS UK Physics Meeting Data challenges Goal validate our computing model and our software How? Iterate on a set of DCs of increasing complexity start with data which looks like real data Run the filtering and reconstruction chain Store the output data into our database Run the analysis Produce physics results To understand our computing model Performances, bottle necks, etc… To check and validate our software

3. 05/09/2001ATLAS UK Physics Meeting But: Today we don’t have ‘real data’ Needs to produce ‘simulated data’ first so: Physics Event generation Simulation Pile-up Detector response Plus reconstruction and analysis will be part of the first Data Challenges

4. 05/09/2001ATLAS UK Physics Meeting ATLAS Kits Each DC will have an associated kit Current kit 1.3.0 for tests, will be replaced for DC0; testing 2.0.3 in October Default kit excludes compilers, but an `all in’ kit exists – more intrusive in OS but usable by more OS versions So far, no Grid/Globus tools included

5. 05/09/2001ATLAS UK Physics Meeting ATLAS kit 1.3.0 Tar file with ATLAS software to be sent to remote GRID sites and used in DC0 Main requirements:  NO AFS  NO root privileges to install the software  Possibility to COMPILE the code  NOT to big Tar file  Should run on Linux platform

6. 05/09/2001ATLAS UK Physics Meeting First version of the ATLAS kit It installs :  SRT (= Software Release Tools) version 0.3.2  a subset of ATLAS release 1.3.1 :  main Atlas Applications code + Makefiles : DiceMain, DicePytMain AtreconMain (Dice = G3 based ATLAS simulation program) (Atrecon = ATLAS Reconstruction program)  ATLAS packages and libraries needed for compilation  CLHEP version 1.6.0.0

7. 05/09/2001ATLAS UK Physics Meeting It requires:  Linux OS (at the moment tested on Redhat 6.1, 6.2, 7.1) Mandrake has problems êCERNLIB 2000 installed êIf you need CERBLIB2000, use kit1 êIf you are on RedHat 7.1, need compilers in kit2 It provides:  all instructions to install / compile / run in a README file  example jobs to run full simulation and reconstruction plus example datacards (DICE, Atrecon)  some scripts to set environment variables, to compile and run

8. 05/09/2001ATLAS UK Physics Meeting It can be downloaded :  http://pcatl0a.mi.infn.it/~resconi/kit/atlas_kit.html  ATLAS_kit.tar.gz (~ 90 MB)  then execute: gtar -xvzf ATLAS_kit.tar.gz  it will open a directory /ATLAS of ~ 500 MB  It has been installed and tested on GRID machines + non-ATLAS machines  sites involved in first tests of the ATLAS kit: Milan, Rome, Glasgow, Lund providing feedback…  Lacks verification kit, analysis tools WORK IN PROGRESS

9. 05/09/2001ATLAS UK Physics Meeting What about Globus? Not needed in current kit (but needed if you want to be part of the DataGrid Test Bed) Will be needed for DC1 (?!) – should be in the Kit if so If installing now, take the version from the GridPP website – the Hey CD-ROM is out of date (RPMs will be available)

10. 05/09/2001ATLAS UK Physics Meeting DC0: start: 1 November 2001 end : 12 December 2001 'continuity' test through the software chain aim is primarily to check the state of readiness for Data Challenge 1 100k Z+jet events, or similar – several times software works: – issues to be checked include G3 simulation on PC farm 'pile-up' handling what trigger simulation is to be run (ATRIG?) reconstruction running. – data must be written/read to/from the database

11. 05/09/2001ATLAS UK Physics Meeting DC1: start: 1 February 2002 end : 30 July 2002 scope increases significantly beyond DC0 – Several sample of up to 10 7 events – Should involve CERN & outside-CERN sites – as a goal, be able to run: O(1000) PC’s 10 7 events –Simulation –Pile-up –Reconstruction 10-20 days

12. 05/09/2001ATLAS UK Physics Meeting Aims of DC1(1) Provide a sample of 10 7 events for HLT studies improve previous statistics by a factor 10 Study performance of Athena and algorithms for use in HLT HLT TDR due for the end of 2002

13. 05/09/2001ATLAS UK Physics Meeting Aims of DC1(2) Try out running 'reconstruction' and 'analysis' on a large scale. learn about our data model I/O performances Bottle necks Note Simulation and pile-up will play an important role

14. 05/09/2001ATLAS UK Physics Meeting Aims of DC1(3) Understand our ‘distributed’ computing model – GRID Use of GRID tools –Data management Dbase technologies –N events with different technologies – distributed analysis Access to data

15. 05/09/2001ATLAS UK Physics Meeting Aims of DC1(4) Provide samples of physics events to check and extend some of the Physics TDR studies data generated will be mainly ‘standard model’ checking Geant3 versus Geant4 understand how to do the comparison understand ‘same’ geometry

16. 05/09/2001ATLAS UK Physics Meeting DC2 start: January 2003 end : September 2003 scope depends on the ‘success’ of DC0/1 goals use of ‘Test-Bed’ 10 8 events, complexity at ~50% of 2006-7 system Geant4 should play a major role ‘hidden’ new physics test of calibration procedures extensive use of GRID middleware Do we want to add part or all of: –DAQ –LVl1, Lvl2, Event filter

17. 05/09/2001ATLAS UK Physics Meeting The ATLAS Data Challenges Project Structure Organisation ATLAS Data Challenges CSG DC Overview Board DC Execution Board DC Definition Committee (DC2) Work Plan Definition WP RTAG WP Reports Reviews NCB Resource Matters Other Computing Grid Projects DataGrid Project TIERs

18. 05/09/2001ATLAS UK Physics Meeting Event generation The type of events has to be defined Several event generators will probably be used –For each of them we have to define the version in particular Pythia –Robust? Event type & event generators have to be defined by –HLT group (for HLT events) –Physics community Depending on the output we can use the following frameworks –ATGEN/GENZ for ZEBRA output format –Athena for output in OO-db (HepMC) –Zebra to HepMc convertor already exists.

19. 05/09/2001ATLAS UK Physics Meeting Simulation  Geant3 or Geant4? DC0 and DC1 will still rely on Geant3 – G4 version not ready Urgently need Geant4 experience  Geometry has to be defined (same as G3 for validation)  Use standard events for validation  The `physics’ is improved for Geant3 simulation, “Slug/Dice” or “Atlsim” framework In both cases output will be Zebra for Geant4 simulation, probably use the FADS/Goofy framework output will be ‘Hits collections’ in OO-db

20. 05/09/2001ATLAS UK Physics Meeting Pile-up Add to the ‘Physics event’ “N” ‘minimum bias events’ –N depends on the luminosity Suggested –2-3 at L = 10 33 – 6 at L = 2 x 10 33 –24 at L = 10 34 –N depends of the detector In the calorimeter N C is ~ 10 times bigger than for other detectors –Matching events for different pile-up in different detectors a real headache! The ‘minimum bias’ events should be generated first, they will then be picked-up randomly when the merging is done –This will be a high I/O operation –Efficiency technology dependent (sequential or random access files)

21. 05/09/2001ATLAS UK Physics Meeting Reconstruction –Run in Athena framework –Input should be from OO-db –Output in OO-db: ESD AOD TAG –Atrecon could be a back-up possibility To be decided

22. 05/09/2001ATLAS UK Physics Meeting Data management Many ‘pieces’ of infrastructure still to be decided –Everything related to the OO-db (Objy or/and ORACLE) Tools for creation, replication, distribution –What do we do with ROOT I/O Which fraction of the events will be done with ROOT I/O –Thousands of files will be produced and need “bookkeeping” and a “catalog” Where is the “HepMC” truth data ? Where is the corresponding “simulated” or AOD data ? Selection and filtering? Correlation between different pieces of information?

23. 05/09/2001ATLAS UK Physics Meeting Data management Several technologies will be evaluated, so we will have to duplicate some data –Same data in ZEBRA & OO-db –Same data in ZEBRA FZ and ZEBRA random-access (for pile-up) –We need to quantify this overhead We have also to “realize” that the performances will depend on the technology –Sequential versus random access files

24. 05/09/2001ATLAS UK Physics Meeting DC0 planning For DC0, probably in September software week, decide on the strategy to be adopted: –Software to be used Dice geometry Reconstruction adapted to this geometry Database –Infrastructure Gilbert hopes (hmmm) that we will have in place ‘tools’ for: –Automatic job-submission –Data catalog and book keeping –allocation of “run numbers” and of “random numbers” ( book keeping) –The ‘validation’ of components must be done now

25. 05/09/2001ATLAS UK Physics Meeting Currently available software, June-Sept2001. atgen-b fortran, Hp only ---------------- Py5.7Jetset74 +code dedicated to B-physics ---------------- Lujets->GENZ bank Particle lev. simulation ZEBRA Detector simulation Dice: slug+geant3 fortran produce GENZ+KINE bank ZEBRA Reconstruction Atrecon fortran,c++ read GENZ+kine produce ATHENA Fast det.simulation Atlfast++ reads GENZ convert to HepMc produce Ntuples New geom TDR geo m Reconstruction C++ reads GENZ +kine convert to HepMc produce Ntuples

26. 05/09/2001ATLAS UK Physics Meeting Simulation software to be available Nov-Dec2001. HepMc? ? Detector simulation Dice: slug+geant3 fortran produce GENZ+KINE bank ZEBRA ATHENA Fast det.simulation Reconstruction C++ reads GENZ +kine convert to HepMc produce Ntuples ATHENA Particle lev. simulation GeneratorModules C++, linux ---------------- Py6 +code dedicated to B-physics ---------------- PYJETS->HepMc --------------- EvtGen BaBar package ( later). Atlfast++ reads HepMc produce Ntuples

27. 05/09/2001ATLAS UK Physics Meeting Analysis –Analysis tools evaluation should be part of the DC –Required for test of the Event Data Model –Essential for tests of Computing Models –Output for HLT studies will be only few hundred events –‘Physics events’ would be more appropriate for this study –ATLAS Kit must include analysis tools

28. 05/09/2001ATLAS UK Physics Meeting Storage and CPU issues in DC1 Testing storage technology will inflate data volume/event (easiest to re-simulate) Testing software chains will inflate CPU usage/event The size of the events with pile-up depends on the luminosity 4 MB per event @ L= 2 x 10 33 15 MB per event @ L= 10 34 The time to do the pile-up depends also on the luminosity 55 s (HP) per event @ L= 2 x 10 33 200 s (HP) per event @ L= 10 34

29. 05/09/2001ATLAS UK Physics Meeting Issues for DC1 –Manpower is the most precious resource; coherent generation will be a significant job for each participating site –Do we have enough hardware resources in terms of CPU, disk space, tapes, data servers … Looks OK Entry-requirement for generation O(100) CPUs (NCB) – clouds What will we do with the data generated during the DC? –Keep it on CASTOR? Tapes? How will we exchange the data? –Do we want to have all the information at CERN?, everywhere? What are the networking requirements?

30. 05/09/2001ATLAS UK Physics Meeting ATLAS interim manpower request from GridPP Requested another post for DC co- ordination and management tools, running DCs, and Grid integration and verification. Looking at declared manpower, this is insufficient in pre-Grid era! Further post for Replication, Catalogue and MSS integration for ATLAS

31. 05/09/2001ATLAS UK Physics Meeting Interim ATLAS request Grid-aware resource discovery and job submission for ATLAS; essential all this be progammatic by DC2. Overlap with LHCb? Should add to this post(s) for verification activities, which is a large part of the work Should also ask for manpower for verification packages

32. 05/09/2001ATLAS UK Physics Meeting Joint meeting with LHCb Common project on experiment code installation Grid-based tools Event selection and data discovery tools (GANGA is an LHCb proposed prototype layer between Gaudi/Athena and Datastores and catalogues)