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eScience and Particle Physics Roger Barlow eScience showcase May 1 st 2007
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  • eScience and Particle PhysicsRoger BarloweScience showcaseMay 1st 2007

  • Particle physics yesterdayParticle physics has pushed the computing envelope ever since the early days- though in the early days the envelope was smaller

  • Particle physics todayToday we have millions of extremely complicated events to interpret

  • Particle physics tomorrowTomorrow the LHC will give us trillions of much more complicated events to interpret

  • What is our computing?Basic tasks fairly simple find tracks from set of points, find particle momenta from track curvature, etc.Data is pretty well constrained and homogenous.But we need to do this on a big scale, for hundreds of millions of events.

  • Big is beautifulIf all the data from the LHC in a year were written to CDs, and the CDs put in a pile, that pile would be 20 km highCommodity computing saved us in the 1990s: PCs got cheap. But thats not enough

  • The GridData analysis can only be achieved as a world-wide exercise using all available computing resourcesThis needs a Grid:The UK GridPP projectand EGEE across Europe

  • What is a Grid?

    Answer 1 (for journalists)The Grid is a virtual supercomputerAnswer 2 (for politicians)Computing coming out of a wall socket, just like electric power Answer 3 (for the rest of us)The Web is computers talking to computers, saying Give me a certain document.The Grid is computers talking to computers. They can say anything.

  • IssuesMany computers available in computer centres Many people who want to use themHow do the people know the computers are there? What facilities they provideHow do the computer centres know which users are allowed to do what? That users are who they say they are?Traditional solution; every user needs an account and password at every centreDoes not scale to large numbers of computers and users

  • Solution Grid certificatesUser details encoded by the RSA algorithm from a trusted Certificate AuthorityProves that whoever presents the certificate are who they say they are. (Modern analogue of the royal seal)User needs only one Grid certificate access everywhereLed (in academia) by UK/European particle physicists /C=UK /O=eScience/OU=Manchester /L=HEP/CN=roger john barlow

    UK CA

  • Solution - VOMSUsers join Virtual OrganisationsCentres negotiate with VOs for usage rights

    UK VOMS system run from Manchester (Physics for GridPP, Computing for NGS). 500 users, 15 VOs, and growingCENTREUserVOVOMS system

  • Solution: pool accountsDeveloped and implemented by Manchester physics

    Neither user nor centre wants individual accounts Single account (griduser) will lead to jobs deleting each others files

    Create generic accounts (ATLAS001, ATLAS002)User assigned a generic account can run jobs

    Account is linked to certificate name so there is an audit trail for antisocial behaviour

  • Solution - GridSiteGridSite developed at Manchester to manage websites using grid credentialsNow used to gridify Web Services used on the gridGridPP website is maintained at Manchester using GridSite

  • Facility Tier21000 dual 2.8 GHz Xeon nodes Petabyte of storage10 Gbit/s networkBought as faculty investment in eScienceReynolds House machine roomManagement through particle physics

  • ResultsWorking anddeliveringCPU cycles

    High uptime and reliability

  • Whos using it?Manchester LHC experimentsNon-Manchester LHC experimentsManchester non LHC experimentsNon-Manchester non-LHC experimentsNon-Particle physics users

  • BiomedDrug design for combating bird flu & other diseases

  • ATLASATLAS trigger testsLarge scale software tests cannot be done at CERN as only ~10 computers availableTests run at Manchester (400 CPUs) insteadATLAS monitoring and calibrationDetectors need frequent calibrating to convert raw signals into useful co-ordinates correctlyComputers at CERN dedicated to actual DAQSolution: ship raw data to Manchester. Process. Ship calibration data backSuccessful large-scale tests show this is possible TriggerDetectorDAQData storageCAL DATAManchester2000 CPUsMonitor

  • BABARExperiment running at Stanford Linear Accelerator studying the difference between matter and antimatterData selection:Copy files from SLAC to Manchester (~5TB)Select ~200 different streams using different criteriaShip files of separate streams back to SLAC

    SLAC computers overloaded with other processing tasksAnticipate direct financial return if successful (common fund rebate to STFC)

  • Financial benefits (past)

    BaBarGridR011454PPARC138KTestbedR011857PPARC10KGrid SecurityR011409PPARC461KEGEER013652EU112K Tier2 operationsR011411PPARC311K

  • Financial benefits (future)Grants applied for

    Expect approval though not at full amount requested


  • Summary Particle Physics uses eScienceeScience benefits from Particle PhysicsManchester is leading in ideas and computer power thanks to bright people and strong supportBenefits in international recognition and research incomeLong may it continue!