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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