The ALICE short-term use case DataGrid WP6 Meeting Milano, 11 Dec 2000Piergiorgio Cerello 1 Physics...

The ALICE short-term use caseThe ALICE short-term use case

DataGrid WP6 MeetingDataGrid WP6 Meeting

Milano, 11 Dec 2000 Piergiorgio Cerello 1

Physics Performance Report (PPR) Physics Performance Report (PPR) production starting in Feb2001 production starting in Feb2001

Opportunity for a "zero-order" test with Opportunity for a "zero-order" test with GRID tools GRID tools

Get many people in touch with GLOBUSGet many people in touch with GLOBUSBe ready to make use of newly available GRID toolsBe ready to make use of newly available GRID tools

Better define our requirements "experimentally"Better define our requirements "experimentally"

Improve & simplify the production control? Improve & simplify the production control?

The ALICE PPRThe ALICE PPR



Evaluate the ALICE performance with respect to the Evaluate the ALICE performance with respect to the

detection of a set of interesting physics signals detection of a set of interesting physics signals

Pb-Pb event generation Pb-Pb event generation (HIJING, driven by AliRoot) (HIJING, driven by AliRoot)Event tracking (GEANT3, driven by AliRoot)Event tracking (GEANT3, driven by AliRoot)Full detector simulation (AliRoot)Full detector simulation (AliRoot)

List of "Digits" (Raw Data)List of "Digits" (Raw Data)

Step 1: background simulationStep 1: background simulation

The ALICE PPRThe ALICE PPR



Physics signal generation & digitizationPhysics signal generation & digitizationBackground superpositionBackground superpositionReconstructionReconstruction

List of Points, Tracks, Vertices List of Points, Tracks, Vertices

Step 2: signal simulation + reconstructionStep 2: signal simulation + reconstruction

Evaluation of:Evaluation of:- signal detection acceptance & - signal detection acceptance &

efficiencyefficiency- mass resolution- mass resolution

Step 3: AnalysisStep 3: Analysis

SimulationSimulation



Requirements on mass storage & CPU mainly Requirements on mass storage & CPU mainly come from the simulation of "background" events come from the simulation of "background" events

About About 101044 background events needed background events needed ( (8.4 x108.4 x1044 primary tracks each) primary tracks each)

Mass storage: about 1 GB/eventMass storage: about 1 GB/event> 10 TB> 10 TB storage needed storage needed

Step 1Step 1

CPU: about 24 hours/event CPU: about 24 hours/event on PIII 600 Mhz, 512 MB RAM on PIII 600 Mhz, 512 MB RAM

Memory: about 450 MB/jobMemory: about 450 MB/job

SimulationSimulation



node:/path/run#/event#/galice.root (1 GB)node:/path/run#/event#/<det>_sumDigits.root (100 MB)galice.root ----> Header, Kine, Hits <det>_sumDigits.root ----> Digits for detector <det><det> = ITS, TPC, MUON, PMD, RICH, ZDC & so on

Data output structure: 1 event/directoryData output structure: 1 event/directory

InputInput

Config.CConfig.Cgrun.C grun.C

job_id.errjob_id.errjob_id.datjob_id.dat

OutputOutput

Signal + ReconstructioSignal + Reconstructionn



RemarksRemarks

Step 2Step 2 Requirements on Requirements on workload management & data access workload management & data accessOrganization will depend on the total input sizeOrganization will depend on the total input size

- Need to make input data (background - Need to make input data (background

digitized events) available to any user digitized events) available to any user- Need to superimpose different - Need to superimpose different

physicsphysics signals on the same background signals on the same background

eventevent




Step 2 - Option 1Step 2 - Option 1 - All the digitized data stored at a single site- All the digitized data stored at a single site- Access to any user + data shipping to the- Access to any user + data shipping to the user's site -> processing user's site -> processing - Reconstruction output stored at the - Reconstruction output stored at the

user's siteuser's site

Remarks:Remarks: - Need for a Workload manager- Need for a Workload manager- Network performance: 1 TB x # of - Network performance: 1 TB x # of

usersusers




Step 2 - Option 2Step 2 - Option 2 - Distributed storage of digitized data- Distributed storage of digitized data

- Scheduling of signal superposition & - Scheduling of signal superposition & reconstrution jobs reconstrution jobs

- Reconstruction output stored at the - Reconstruction output stored at the user's siteuser's site

Remarks:Remarks: - Workload managed locally- Workload managed locally- Network performance: 0.1 TB x # of - Network performance: 0.1 TB x # of

signalssignals




Step 2 - Option 3Step 2 - Option 3 - Distributed storage of digitized data- Distributed storage of digitized data

- Access to any remote user + data - Access to any remote user + data shipping toshipping to the user's site the user's site

- Reconstruction output shipped to a single - Reconstruction output shipped to a single sitesite (which might be different for different signals) (which might be different for different signals)

Remarks:Remarks: - Need for a Workload manager- Need for a Workload manager- Network performance: 1 TB x # of - Network performance: 1 TB x # of

usersusers

AnalysisAnalysis



Step 3Step 3 - Distributed storage of reconstructed data - Distributed storage of reconstructed data

- Access to any remote user + data - Access to any remote user + data shipping toshipping to the user's site the user's site

- Analysis- Analysis

Remarks:Remarks: - Workload managed locally- Workload managed locally- Need for a data manager- Need for a data manager- Network performance: 0.1 TB x # of - Network performance: 0.1 TB x # of

usersusers

The ALICE PPR: where?The ALICE PPR: where?



Sites quoted for the PPR productionSites quoted for the PPR production

No detailed sharing decided yetNo detailed sharing decided yet

CERNCERNAmsterdam - NIKHEFAmsterdam - NIKHEFCagliari - INFNCagliari - INFNCatania - INFNCatania - INFNColumbus - Ohio State UniversityColumbus - Ohio State UniversityDarmstadt - GSIDarmstadt - GSIDubna - JINRDubna - JINRLyon - IN2P3Lyon - IN2P3Padova - INFNPadova - INFNTorino - INFNTorino - INFN

Status: ALICE SoftwareStatus: ALICE Software

Milano, 11 Dec 2000 Piergiorgio Cerello

GCC 2.95.2 as compiler, recompiled for i686ROOT v 2.25/03 patched & compiledAliRoot v3.04pre

AliRoot is rapidly evolving towards version3.04 which will be used for the Physics Performance Report production

AliRoot framework development for the PPR production at CERN

GRID (Globus) tests between sites quoted for the PPR production

installed and working at all sites - preliminary installation kit available


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Status: GRID SoftwareStatus: GRID SoftwareGlobus v.1.1.3 installed in Cagliari, Catania, Columbus, Lyon, Torino

Dubna, GSI, Saclay: expected by the end of the yearMerida: work just starting on the GRID item



Lower-level job manager: Cagliari, Catania, GSI: LSF Lyon: BQS Torino: PBS

Columbus, Dubna, GSI, Merida, Saclay: to be defined

Test activities - up to nowTest activities - up to now overhead tests using a CPU-bound program;

benchmark tests using NAS (System Division at NASA

Ames Research Center) Software

functionality tests (elementary job submission using

globus-job-run and globusrun commands);

Run AliRoot (1 full event) with the whole Alice

detector on the farms [no Grid]

test submission and execution stages on the PBS

(LSF, ...) farm driven by a local host [Grid]Milano, 11 Dec 2000 14


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Test activities - up to nowTest activities - up to now

driven by GLOBUS

submitted from Torino, executed in Catania

CPU load monitored through the WEB

data output stored remotely

stdout & stderr shipped back to submitting machine

Execution time: 24 hMilano, 11 Dec 2000 15


Piergiorgio Cerello

Remote generation of a full ALICE background event

Test activities - plansTest activities - plans

test submission and execution stages on local farms driven by remote sites [Grid]

repeat between different partners [Grid]

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Repeat with input/output file transferRepeat with input/output file transfer



Piergiorgio Cerello

Test activities - Step2Test activities - Step2

Presently planned tests refer Presently planned tests refer to the simulation stage ("Step1")to the simulation stage ("Step1")

What about reconstruction & analysis ("Step2")?What about reconstruction & analysis ("Step2")?

More demanding from the point of More demanding from the point of view of GRID toolsview of GRID tools

Need access to & shipping of more than Need access to & shipping of more than 10 TB of distributed data10 TB of distributed data



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ConclusionsConclusions

Large number of sites participating to GRID Large number of sites participating to GRID tests & quoted for the PPR production (Step1)tests & quoted for the PPR production (Step1)

The use of GLOBUS as manager for the PPRThe use of GLOBUS as manager for the PPRproduction is becoming a reliable optionproduction is becoming a reliable option

Reconstruction & Analysis (Step2) for the ALICE Reconstruction & Analysis (Step2) for the ALICE Physics Performance Report will soon require Physics Performance Report will soon require more advanced GRID tools more advanced GRID tools



Piergiorgio Cerello

The ALICE short-term use case DataGrid WP6 Meeting Milano, 11 Dec 2000Piergiorgio Cerello 1 Physics...

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