McCubbin: von Ruden Review 26 Oct 001 ATLAS Computing. Introduction + Overview Norman McCubbin (RAL)...

McCubbin: von Ruden Review 26 Oct 00

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ATLAS Computing. Introduction + Overview

Norman McCubbin (RAL)Computing Co-ordinator


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ATLAS Computing: Introduction + Overview

Organisation: people/task matrixMain milestonesSummary of major activities“Projectisation” of Computing:

schedule, PBS; effort; ‘holes’; software agreements; hardware resources:

National Computing Board; World-Wide Computing; MONARC; CERN Review


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Computing organization

simulation reconstruction database coordinator

QC group simulation reconstruction database Arch. team

Event filter

Technical Group

National Comp. BoardComp. Steering

Group Physics

Comp. Oversight Board

Detector system


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ATLAS Detector/Task matrix

F. TouchardV. VercesiEvent Filter

H.P. BeckT. Hansl-KozaneckiTrigger/DAQ

S. TapproggeLVL2 trigger

S. GoldfarbA. RimoldiJ.F. LaporteG. PoulardMuon

T. LeCompteA. SolodkovF. MerrittA. SolodkovTile calorimeter

S.Simion/R.SobieM. LeltchoukS.RajagopalanJ. CollotLiquid Argon

S.BentvelsenF.LuehringD. RousseauD. BarberisInner Detector

D.Malon/RD Schaffer

K.AmakoD. RousseauN. McCubbinChair

DatabaseSimulationReconstructionOffline Coordinator

S. George

Physics Co-ordinator: F.Gianotti Chief Architect: D.Quarrie


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ATLAS Computing: Introduction and Overview

The major schedule items (with indicative dates) for the next 2-3 years are: Develop framework through series of releases, leading to first ‘fully-

functional’ version by end 01. Profit from TestBeam requirements, starting this year. Major effort to validate Geant4 for ATLAS, with simulation workshop Dec.

2000 and Physics workshop Spring September 2001. Have first version of reconstruction software ready (start 01) for Event

Filter analysis for TDAQ TDR. MDC0: 100k event ‘continuity test’ for end 01. Chain (G4 simulation and ATLAS code) ready for MDC1 (“0.1% PB”) to start in

02. (Open issues: how to ‘trigger’; involvement of Regional Centres (RC)) Computing TDR: deliver end 02. (Open issues: date) MDC2: First half 03. “10% of 1PByte”. Must, inter alia, validate computing

model. (Open issues: how to ‘trigger’; scale; collaboration with other experiments.)


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Simulation: major effort is focussed in Geant4 (G4) physics

validation for ATLAS; very detailed studies (G4/G3/Test-Beam) are now in

progress: G4 looks promising but of course needs tuning/refining. ATLAS results presented at several conferences/work-shops.

close collaboration with G4 team (monthly meetings); ATLAS G4-physics workshop Dec. 4+5; major goal is G4 ‘good enough’ for Mock Data

Challenge 0 (end 2001). G3 as ‘insurance’?


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Reconstruction: first target is to have C++ versions of reconstruction

working via framework (Athena) for end of this year; muon code will be MuonBox (Fortran);

Lar code already available via Athena; MuonBox and xKalman++ have been interfaced ‘privately’ to Athena, some tidying still needed.

these versions of recon. codes will be used (on existing Geant3 data) for TDAQ TDR. (Maybe later versions, depending on TDAQ TDR date);

Reconstruction w/shop to assess progress Oct 24.


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ATLAS Computing: Introduction + Overview ‘Projectisation’ of Computing:

Scale, scope, duration, and cost of ATLAS computing project all argue for a greater formal ‘projectisation’ of computing than has been done in previous experiments (LEP, HERA, UA1,2 , etc.)

Indeed, my time as Computing Co-ordinator has strengthened my conviction that this is not only desirable but essential.

Details of our planning etc. so far can be seen at: http://cern.ch/Atlas/GROUPS/SOFTWARE/OO/planning

Considerable effort to harmonise with USA at PBS level to avoid duplication and confusion. (See presentations of Meinhard and Wenaus)

We have prepared a first version of a schedule, which includes the major milestones mentioned above, but also gives much much more detail.


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ATLAS Computing: Introduction + Overview This schedule is by no means ‘final’ or complete. (e.g.

‘World-wide computing’ not yet entered in detail, and ‘dependencies’ need much more detail). But it does give significant detail through to end 2001, and is already proving valuable for Computing Steering Group (CSG): part of each (monthly) meeting is devoted to schedule ‘follow-up’.

A first set of LHCC and ATLAS Exec. Board (EB) milestones has been defined. This list will surely grow.


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ATLAS Computing; Introduction + Overview PBS is used to estimate effort required to deliver the

computing project. It is clear that the entire project (including ‘core’

software and detector-specific software) requires approx. 100 ‘full-time-equivalent’ (fte) per year from now until…… (see next slide)

It is also clear that we have some urgent and obvious ‘vacancies’ right now.

I have sent round (in August) a first list of ‘infrastructure’ tasks to be filled. There has been some response, but by no means enough!


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ATLAS Computing: Introduction + Overview ‘Core’ effort estimate (fte’s): 2000 2001 2002 2003 2004 2005 sub-T O T A L (1-8) 30.2 33.4 30.6 24.2 23.3 23.4 ======================================

T O T A L (1-12) 34.6 47.2 46.6 42.2 39.3 39.4 (1-8) includes framework, dBase, core management,… (1-12) adds in world-wide computing, GRID, MDC’s. N.B. above is requirement, we don’t have

it all!


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ATLAS Computing: Introduction + Overview It has also been recognised for some time that

computing (hardware definitely, software probably) will require, and benefit from, Computing MoU.

This emphasises the point that CERN cannot provide the major share of these resources; they have to come from the other institutes. (CERN will provide some, of course..)

More on the hardware side in a moment; on the software side the main benefit (in my opinion) of an MoU is to commit institutes in the same way as they feel committed by detector MoU.


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ATLAS Computing: Introduction + Overview Since the signing of MoU is some way off, and because the whole

idea is new for computing, we have been developing the idea of “software agreements”, which could, eventually, form part of Computing MoU.

The policy paper on software agreements has been approved by the National Computing Board, and by the ATLAS CB in June 2000.

We have just launched, through the NCB, a list of tasks which could be covered by ‘core’ software agreements.

Idea of software agreement (swa) is to get formal institute commitment. Thus it helps ATLAS; it may also help ATLAS members in arguing for resources in their institute.

Hope is to get first swa (Control Framework with USA) signed by end of the year.


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ATLAS Computing: Introduction + Overview On hardware resources, there is a lot of work going on, stimulated

by the following (related) points: as mentioned above, much of the money (and effort) for computing

hardware and infrastructure will have to come from outside CERN; scale is such that Funding Agencies will have to be asked ‘officially’ for support;

a possible model for ‘World-Wide Computing’ was discussed already at the time of the ATLAS and CMS Computing TPs: major computing centres (‘Regional Centres’) in a few regions which act as computing ‘hubs’ for their region(s). Thus you do not ‘copy from CERN’ every time; required data is copied to your Regional Centre ‘once’, etc. etc.

This thinking has been elaborated in considerable detail in the MONARC project. (RDxx: participation from all LHC experiments)

It is also now clear that estimates of resource requirement will be one of the most important outcomes of the CERN Review.


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H.Hoffmann launched idea of CERN Review of LHC Computing in second half of 1999. Announced at Marseille workshop in September 99.

Aims: assess state of work and preparations in experiments

and IT; provide input for Computing MoUs, which should be put

in place in 2001;recommend actions and in particular common actions

between experiments and IT Division that will help to achieve desired goals within existing resources;

first draft of report December 2000 (?).


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ATLAS week Oct 2000: Introduction to Computing

Review organised as Steering Committee (Chair S.Bethke) and three ‘technical panels’:

Panel 1: ‘world-wide computing model’: chair D.Linglin, ATLAS: A.Putzer, L.Perini

Panel 2: ‘software’: chair M.Kasemann, ATLAS: D.Barberis, M.Bosman

Panel 3: ‘management and resources’: chair M.Calvetti, ATLAS: J.Huth, H.Meinhard

Inevitably some overlap between panels, particularly 1 and 3. Steering Committee meets monthly (since Jan. 00) All LHC experiments and IT have now had several sessions

(presentations and discussions) with each of the Panels. This interaction is now more or less complete. Panel 2 (internal) report is finished.


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Panels 1 and 3 will, in due course, produce up-to-date estimates of LHC computing resources required and costs.

CERN Management has indicated that it will not make any statement on what part of LHC computing costs will be covered by CERN until it has had a chance to consider the findings of the CERN Review.

For Steering Committee to do its job properly (digest information from panels; think; write) will still take a couple of months. A verbal (progress) report has just been presented by Hans Hoffmann to the October Resource Review Board.


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Much of the subject matter discussed by Panels 1 and 3 of the CERN Review is also of prime concern to the ATLAS National Computing Board (NCB), Chairman: Alois Putzer (Heidelberg)

Stimulated in part by CERN Review and various GRID activities, NCB has now formed w/groups which, as a first step, will gather information (‘what’s going on’) on GRID, Regional Centres etc.

For several (related) reasons the whole topic of ‘world-wide computing’ has, rightly, moved up the agenda in the last few months.

In ATLAS we have used a plausible estimate of event size (1MB) and trigger rate (100Hz) for several years. (As have CMS) Following the very detailed Physics (TDR) and Trigger (TP) studies, we have much more refined and understood estimates…. But they are higher (‘270x2’ at 10^33). This is being addressed, vigorously.


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There has been a lot of progress since the January ‘00 ‘von Ruden’:

framework/architectureReconstruction CodeSimulationorganisational infrastructure (planning etc.)

And the USA contribution has been very significant.

ATLAS Computing effort needs your continuing and ongoing support.

McCubbin: von Ruden Review 26 Oct 001 ATLAS Computing. Introduction + Overview Norman McCubbin (RAL)...

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