Symmetry Beauty

Physics

Grid

Large Hadron Collider

Particle Physics

Condensed Matter

Astrophysics

Cosmology

Nuclear Physics

Atomic Physics

Biological Physics

Avoiding Gridlock

Tony DoyleParticle Physics Masterclass

Glasgow, 11 June 2009

Outline

Introduction – Origin - Why?

What is the Grid?

How does the Grid work?

When will it be ready? The

IcemenCometh

Historical Perspective

The World Wide Web

a global information system which users can read and write via computers connected to the Internet

“born” on March 13th 1989:

A proposal was

submitted

“information

Management”• Tim Berners-Lee• CERN

1989-91: DevelopmentThe first three years were a phase of

persuasion to get the Web adopted… 1992-1995: Growth

the load on the first Web server ("info.cern.ch") rose steadily by a

factor of 10 every year…1996-1998: Commercialisation

Google and other search engines1999-2001: "Dot-com" boom

(and bust)2002-Present: The ubiquitous Web

Web 2.0: blogs and RSS

Data is everywhere…

Q: What is done with the data?

Nothing Read it Listen to it

Watch it Analyse it

23Read A

Read BC = A + BPrint C 5

ComputerProgram

"Job"

Calculate how proteins fold

Calculate what the weather is going to do

Q: How much data have humans produced? 1,000,000,000,000,000,000,000 Bytes

1 zettabyte or 1021 Bytes (~ doubling each year)

According to IDC, as of 2006 the total amount of digital data in existence was 0.161 zettabytes; the same paper estimates that by 2010, the rate of digital data generated worldwide will be 0.988 zettabytes per year.

Why “Grid”?

Analogy with the Electricity Power Grid

'Standard Interface'

Power Stations

Distribution Infrastructure

Computing Grid

Computing and Data Centres

Fibre Optics of the Internet

Why do particle physicists need the Grid?

4 Large Experiments

CERN LHCThe world’s most powerful particle accelerator

Why do particle physicists need the Grid?

Example from LHC: starting from this event

We are looking for this “signature”

Selectivity: 1 in 1013

Like looking for 1 person in a thousand world populations

Or for a needle in 20 million haystacks!

• ~100,000,000 electronic channels

• 800,000,000 proton-proton

interactions per second

• 0.0002 Higgs per second

• 10 PBytes of data a year

• (10 Million GBytes = 14 Million CDs)

Concorde(15 Km)

Mt. Blanc(4.8 Km)

One year’s data from LHC would fill a stack of CDs

20km high

Data Grid

• The Grid enables us to

analyse all the data that

comes from the LHC

• Petabytes• 100,000 CPUs

• Distributed around the world

• Now used in many other areas

The Grid

1. Rare Phenomena - Huge Background

9 or

ders

of m

agni

tude

The HIGGS

All interactions

“When you are face to face with a difficulty you are up

against a discovery” Lord Kelvin

2. Complexity

Why (particularly) the LHC?

Four LHC Experiments

ALICE

- heavy ion collisions, to create quark-gluon plasmas

- 50,000 particles in each collision

LHCb

- to study the differences between matter and

antimatter

- producing over 100 million b and b-bar mesons

each year

ATLAS

- general purpose: origin of mass, supersymmetry,

micro-black holes?

- 2,000 scientists from 34 countries

CMS

- general purpose detector

- 1,800 scientists from 150 institutes

“One Grid to Rule Them All”?

The Challenges I: Real-Time Event Selection

LEVEL-1 Trigger Hardwired processors (ASIC, FPGA) Pipelined massive parallel

HIGH LEVEL Triggers Farms of

processors

10-9 10-6 10-3 10-0 103

25ns 3µs hour yearms

Reconstruction&ANALYSIS TIER0/1/2

Centers

ON-lineOFF-line

sec

Giga Tera Petabit

9 or

ders

of

mag

nitu

de

Time

Real-Time In-Time

Understand/interpret data via numerically intensive simulations

• Many events– ~109 events/experiment/year

– >~1 MB/event raw data– several passes required

Worldwide Grid computing requirement (2008):~300 TeraIPS

(100,000 of today’s fastest processors connected via a Grid)

16 Million channels

100 kHzLEVEL- 1 TRIGGER

1 MegaByte EVENT DATA

200 GigaByte BUFFERS500 Readout memories

3 Gigacell buffers

500 Gigabit/s

Gigabit/s SERVICE LAN PetaByte ARCHIVE

Energy Tracks

Networks

1 Terabit/s(50000 DATA CHANNELS)

20 TeraIPS

EVENT BUILDER

EVENT FILTER

40 MHzCOLLISION RATE

Charge Time Pattern

Detectors

Grid Computing Service 300 TeraIPS

The Challenges II: Real-Time Complexity

Share more than information

Efficient use of resources at many institutes

Leverage over other sources of funding

Data, computing power, applications

Join local communities

Challenges:• share data between thousands of scientists with multiple interests

• link major and minor computer centres• ensure all data accessible anywhere, anytime

• grow rapidly, yet remain reliable for more than a decade• cope with different management policies of different centres

• ensure data security• be up and running routinely

Solution – Build a Grid

Middleware is the Key

MIDDLEWARE

CPUDisks, CPU etc

PROGRAMS

OPERATING SYSTEM

Word/Excel

Email/Web

Your Program

Games

CPUCluster

UserInterfaceMachine

CPUCluster

CPUCluster

Resource Broker Information Service

Single PC Grid

DiskServer

Your Program

Middleware is the Operating System of a distributed

computing system

Replica CatalogueBookkeeping

Service

Something like this…

… or this

griduiJDL

VOMS

WLMS

JS

RB

LFC

BDII

Logging & Bookkeeping

33

CPU Nodes Storage

Grid Enabled Resources

CPU Nodes Storage

Grid Enabled Resources

CPU Nodes Storage

Grid Enabled Resources

CPU Nodes Storage

Grid Enabled Resources

44

55

Submitter

6677

88 99

1010

00 VOMS-proxy-init

11 Job Submission

22

Job S

tatu

s?1111Job Retrie

val

An open operating system does not only

have advantages?

LCG OSG NDG NGS

… or this

Who do you trust?

No-one?

It depends on what you want… (assume its scientific collaboration)

How do I Authorise? Digital Certificates

REAL and SIMULATED data

Data Structure

Raw DataRaw Data

Reconstruction

Data Acquisition

Level 3 trigger

Trigger TagsTrigger Tags

Event Summary Data

ESD

Event Summary Data

ESD Event Tags Event Tags

Physics Models

Monte Carlo Truth DataMonte Carlo Truth Data

MC Raw DataMC Raw Data

Reconstruction

MC Event Summary DataMC Event Summary Data MC Event Tags MC Event Tags

Detector Simulation

Calibration DataCalibration Data

Run ConditionsRun Conditions

Trigger System

Physics Analysis

ESD: Data or Monte CarloESD: Data or Monte Carlo

Event Tags Event TagsEvent Selection

Analysis Object DataAnalysis Object DataAnalysis Object DataAnalysis Object DataAnalysis Object Data

AOD

Analysis Object Data

AOD

Calibration DataCalibration Data

Analysis, Skims

Raw DataRaw Data

Tier 0,1Collaboration

wide

Tier 2Analysis

Groups

Tier 3, 4PhysicistsPhysics Analysis

Physics

Objects Physics

Objects

Physics

Objects

INC

RE

AS

ING

DA

TA

FLO

W

Grid Infrastructure

Tier 0

Tier 1National centres

Tier 2Regional groups

Institutes

Workstations

Offline farm

Online system

CERN computer centre

RAL,UK

ScotGrid NorthGrid SouthGrid London

FranceItalyGermanySpain

Glasgow Edinburgh Durham

Structure chosen for particle physics.Different for others.

11 T1 centres

An Example - ScotGrid

Just in time for the LHCMachine Room

Downstairs

The Grid

ArcheologyAstronomy

AstrophysicsCivil Protection

Comp. ChemistryEarth Sciences

FinanceFusion

GeophysicsHigh Energy Physics

Life SciencesMultimedia

Material Sciences…

>250 sites48 countries

>50,000 CPUs>20 PetaBytes>10,000 users

>150 VOs>150,000 jobs/day

1. Why? 2. What? 3. How? 4. When?

From Particle Physics perspective the Grid is:1. needed to utilise large-scale computing resources efficiently and securely

2. a) a working system running today on large resourcesb) about seamless discovery of computing resources

c) using evolving standards for interoperationd) the basis for computing in the 21st Century

3. Using middleware

4. Now available – ready for LHC data

Avoiding Gridlock?

Avoid computer lockup using a Grid

Avoiding Gridlockprovided you have a star

network(basis of the internet)..

Computing is then almost limitless

Thank YOU