il progetto “grid ” ed il calcolo dei futuri esperimenti · digital certificate is basis of...
TRANSCRIPT
![Page 1: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/1.jpg)
Il progetto “GRID ” ed il calcolo dei futuri esperimenti
Marco Serra - INFN Roma
![Page 2: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/2.jpg)
Acknowledgements
a questa presentazione hanno contribuito con idee e materiale molte persone:
EGEE training teamJ. Templon (NIKHEF)D. Bonacorsi & F. Safai (CMS)V. Vagnoni (LHCb)C. Palomba (Virgo - INFN Roma)B. Taglienti (Gruppo Teorico - INFN Roma).........
![Page 3: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/3.jpg)
Indice
Idea del talk : introdurre i concetti del “Grid computing” assumendo nessuna conoscenzapregressa
Struttura di una Griglia Computazionale (Grid)
Modelli di calcolo di alcuni esperimenti che utilizzano la Grid
Conclusioni
![Page 4: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/4.jpg)
“tipica” risoluzione di un problema scientifico
risolvere un problema: → trovare un programma
se non esiste scriverlo .....
eseguire il programmadevo accedere a dei dati per l’esecuzione? l’output e’ “voluminoso” ?
analisi dei risultatiaccedo ai dati ed eseguo un altro programma per fare istogrammi, grafici, fit, ..........
risorse necessarie definite dalla complessita’ del problemaquante CPU quanto spazio discodove sono i dati che mi servono - rete................
![Page 5: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/5.jpg)
Researchers in many locations need to share resources
Scientific instruments, data stores and computers in many locations
Before Grids
SSH, SCP, blood, sweat and tears…and little support for collaboration
There must be a better way of doing this!!!
![Page 6: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/6.jpg)
The GRID: networked data processing centres and ”middleware” software as the “glue” of resources.
Researchers perform their activities regardless geographical location, interact with colleagues, share and access data
Scientific instruments and experiments provide huge amount of data
With Grids
![Page 7: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/7.jpg)
Che cos’e’ la “Grid Technology”? (1)
L’obiettivo principale dei progetti di Grid e’ lo sviluppo di un insieme coerente di risorse di calcolo (“Grid”), distribuite su scala geografica.
La Grid dovra’ garantire la gestione di dati di differenti comunita’ di utenti (“Virtual Organizations” - VO) - fino alla scala del “Peta-Byte” … utilizzando “computing power”distribuito.
Una Griglia Computazionale dovra’ fornire una interfaccia uniforme e sicura ai suoi “customers” (ed alle sue “resources”), distribuendo un servizio affidabile e accessibile da “qualsiasi luogo”.
![Page 8: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/8.jpg)
Che cos’e’ la “Grid Technology”? (2)
……e’ quel “bit” tra le applicazioni degli utenti (o degli esperimenti) ed il “computer system” di un particolare sito (istituto/laboratorio);
… per gli utenti: e’ quel “bit” di cui non vogliamo preoccuparci, purche’ esista !!!!
... e sia “sicuro”;
Analogia con le griglie-elettriche: si inserisce un “dispositivo”nella presa nel muro e funziona… e non ci interessano le centrali elettriche di produzione, la rete di distribuzione, i cavi del HV ……
![Page 9: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/9.jpg)
The Single Computer
The Operating System enables easy use of
Input devicesProcessorDisksDisplayAny other attached devices
Disks, Processor, Memory, …
Application Software
Operating
System
![Page 10: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/10.jpg)
The Local Area Network
Disks, Processor, …
Application Software
Operating System on each resource
Middleware for connecting to othercomputers, servers, printers, …
User just perceives “shared resources”, with no regard to location in the building:
- Authenticated by username / password
- Authorised to use own files,…
![Page 11: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/11.jpg)
A Grid of Resources
INTERNETINTERNET
Disks, Processor, …
Application Software
Operating System
Middleware for connecting to other computers, …
Grid Middleware
![Page 12: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/12.jpg)
The components of a Grid
Infrastructurenetworking, computational resources, storage resources, …
Middlewarethe operating system of the grid, running on all resources.
Operations infrastructureRun enabling services (people + software)
Virtual Organization managementProcedures for gaining access to resources
![Page 13: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/13.jpg)
Different Perspectives
Users need single sign-on: the ability to logon to a machine and have the user’s identity passed to other resources as requiredTo trust owners of the resources they are using
Providers of resources (computers, disks, databases,..) needrisks to be controlled: they are asked to trust users they do not knowMinimise impact on security An ability to trace who did what.
The solution comes fromVirtual OrganisationsDigital Certificates
![Page 14: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/14.jpg)
Users and Virtual Organisations
Virtual Organisations and trustUser joins a Virtual OrganisationDigital certificate is basis of Authentication and Authorisation.Identity passed to other resources you use, where it is mapped to a local account – the mapping is maintained by the Virtual Organisation.The user trusts the Virtual Organisation to only use resources that are safe and secure
![Page 15: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/15.jpg)
Resource-Provider’s and VO’s
Virtual Organisations and trustA Resource-Provider trusts a Virtual OrganisationThe Virtual Organisation trusts its users
Common agreed policies establish rights for a Virtual Organization to use resources
Each resource provider has different usage and security considerations that must be accounted for.
![Page 16: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/16.jpg)
X.509 Certificates
User
Certificate Authority
Public keyPrivate keycertificate
CA
Resource (site offering services)
![Page 17: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/17.jpg)
Main Services of a Grid Architecture
Service providersPublish the availability of their services via information systemsSuch services may come-and-go or change dynamicallya site that offers x CPUs and y GB of storage
Service requestersSingle sign-on: log into the grid onceUse brokering services to find a needed service and employ it
Service brokersRegister and categorize published services and provide search capabilities
Resource Broker selects the best site for a “job”Catalogues of data held at each siteFile Trasfer service
![Page 18: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/18.jpg)
Main Logical Types
User Interface (UI)
Information Service
Computing Element (CE)Frontend NodeWorker Nodes (WN)batch system
Storage Element (SE)
Replica Catalog
Resource Broker (RB)
![Page 19: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/19.jpg)
Attivita’ di un “Grid user”
Grid User
“Grid”
“definizione logica di un problema”(… “algoritmo”/ “tipo di dati” …)
InputSandbox
“risultato”… “grafici”/”subset di dati”/ …
Output Sandbox
![Page 20: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/20.jpg)
Grid User
UserInterface
CComputingomputingEElementlementWWorkerorkerNNodesodes
Tipico “Grid-job life-cicle”
ResourceResource BrokerBrokerI II I
L & BL & B
SStoragetorageEElementlement
ReplicaReplicaCatalogueCatalogue
VOVOCACA Grid-Map
SecuritySecurity
IS IS
OS
OSApplicationApplication
![Page 21: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/21.jpg)
Grid projects
Many Grid development efforts — all over the world
•OSG•NASA Information Power Grid•DOE Science Grid•NSF National Virtual Observatory•NSF GriPhyN•DOE Particle Physics Data Grid•NSF TeraGrid•DOE ASCI Grid•DOE Earth Systems Grid•DARPA CoABS Grid•NEESGrid•DOH BIRN•NSF iVDGL
•WLCG•EGEE(2)•DataGrid (CERN, INFN, ...)•EuroGrid (Unicore)•DataTag (CERN,…)•Astrophysical Virtual Observatory•GRIP (Globus/Unicore)•GRIA (Industrial applications)•GridLab (Cactus Toolkit)•CrossGrid (Infrastructure Components)•EGSO (Solar Physics)
•UK – OGSA-DAI, RealityGrid, GeoDise, Comb-e-Chem, DiscoveryNet, DAME, AstroGrid, GridPP, MyGrid, GOLD, eDiamond, Integrative Biology, …•Netherlands – VLAM, PolderGrid•Germany – UNICORE, Grid proposal•France – Grid funding approved
•Italy – INFN Grid•Eire – Grid proposals•Switzerland - Network/Grid proposal•Hungary – DemoGrid, Grid proposal•Norway, Sweden - NorduGrid
![Page 22: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/22.jpg)
25 Universities4 National Labs2800 CPUs
July 2005
140 Grid sites
34 countries
12000 CPUs
July 2005
140 Grid sites
34 countries
12000 CPUs
30 sites3200 cpus
![Page 23: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/23.jpg)
INFN Grid & GARR
http://grid-it.cnaf.infn.it
![Page 24: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/24.jpg)
Ma chi usa la Grid?
Alcuni esempi
Fisici della alte energieapprocci differenti per esperimenti differenti
Esperimenti di onde gravitazionali
Fisici Teorici
..... e molti altri
![Page 25: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/25.jpg)
We have a problem …
Place event info on 3D map
Trace trajectories through hits
Assign type to each track
Find particles you want
This is “relatively easy” case
Atlas
![Page 26: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/26.jpg)
… this problem is not easy at all
![Page 27: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/27.jpg)
interactivephysicsanalysis
physicsanalysisphysicsanalysis
detector
event summary
data
rawdata
eventreprocessing
eventreprocessing
eventsimulation
eventsimulation
analysis objects(extracted by physics topic)
event filter(selection &
reconstruction)
event filter(selection &
reconstruction)
processeddata
Data Handling and Computation for Physics Analysis
![Page 28: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/28.jpg)
Scales
To reconstruct and analyze 1 event takes about 90 seconds (....)
Maybe only a few out of a million are interesting. But we have to check them all!
Analysis program needs lots of calibration; determined from inspecting results of first pass.
Each event will be analyzed several times!
![Page 29: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/29.jpg)
online systemmulti-level triggerfilter out backgroundreduce data volume
level 1 - special hardware
40 MHz (40 TB/sec)level 2 - embedded processorslevel 3 - PCs
75 KHz (75 GB/sec)5 KHz (5 GB/sec)100 Hz(100 MB/sec)data recording &offline analysis
One of the four LHC detectors
![Page 30: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/30.jpg)
Scales (2)
90 seconds per event to reconstruct and analyze
100 incoming events per second
To keep up, need either:A computer that is nine thousand times faster, ornine thousand computers working together
Moore’s Law: wait 20 years and computers will be 9000 times faster (we need them in 2007!)
![Page 31: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/31.jpg)
CERN18%
All Tier-1s39%
All Tier-2s43%
CERN12%
All Tier-1s55%
All Tier-2s33%
CERN34%
All Tier-1s66%
CPU Disk Tape
Summary of Computing Resource RequirementsAll experiments - 2008From LCG TDR - June 2005
CERN All Tier-1s All Tier-2s TotalCPU (MSPECint2000s) 25 56 61 142Disk (PetaBytes) 7 31 19 57Tape (PetaBytes) 18 35 53
CNAF1045
∼ 95.000 intel core duo D930 ∼ 230.000 dischi da 250GB
LHC computing needs
![Page 32: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/32.jpg)
LHC user distribution
Europe: 267 institutes, 4603 usersElsewhere: 208 institutes, 1632 users
![Page 33: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/33.jpg)
HEP Motivation for Grids
Trivially parallel problemLarge Scales: 100k CPUs, petabytes of data
(if we’re only talking ten machines, who cares?)
Large Dynamic Range: bursty usage patternsWhy buy 25k CPUs if 60% of the time you only need 900 CPUs?
Multiple user groups (& purposes) on single systemCan’t “hard-wire” the system for your purposes
Wide-area access requirementsUsers not in same lab or even continent
![Page 34: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/34.jpg)
Solution using Grids
Trivially parallel: break up problem “appropriate”-sized pieces
Large Scales: 100k CPUs, petabytes of dataAssemble 100k+ CPUs and petabytes of mass storageDon’t need to be in the same place!
Large Dynamic Range: bursty usage patternsWhen you need less than you have, others use excess capacityWhen you need more, use others’ excess capacities
Multiple user groups on single system“Generic” grid software services
Wide-area access requirementsPublic Key Infrastructure for authentication & authorization
![Page 35: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/35.jpg)
CMSATLAS
LHCbCERN
Tier 0 Centre at CERN
physics group
LHC Computing Model
regional group
Tier2
Lab a
Uni a
Lab c
Uni n
Lab m
Lab b
Uni bUni y
Uni x
physicsdepartment
α
β
γDesktop
Germany
Tier 1
USAUK
France
Italy
……….
Spain
……….
LHC Computinginfrastructure
CERN Tier 0
Grid technology
![Page 36: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/36.jpg)
Common HEP Use Cases
HEP experiments have “typical” computing tasks
Simulation
Data (Re)Processing
Physics Analysismodel is still under discussion
![Page 37: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/37.jpg)
Simulation
The easiest use caseNo input data, Output can be to a central locationBookkeeping not really a problem (lost jobs ... OK)
Define program version and parametersTune # of events produced per run to “reasonable”value
Submit (needed ev)/(ev per job) jobsWait
Upload output somewhere
![Page 38: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/38.jpg)
Data (Re)Processing
Quite a bit more challenging: there are input files, and you can’t lose jobs
One job per input file (so far)
Data distribution strategy
Monitoring and bookkeeping
Traceability of output (“provenance”)
![Page 39: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/39.jpg)
Tiered architectureT0:
Accepts data from DAQPrompt reconstructionData archive and distribution to T1’s�
CAF (CERN Analysis Facility for CMS):Access to full raw datasetFocused on latency-critical detector trigger calibration and analysis activitiesProvide some CMS central services (e.g. store conditions and calibrations)
7 T1 centers and 25 T2 centers
![Page 40: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/40.jpg)
![Page 41: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/41.jpg)
CMS T1 functionsCMS T1 functionsScheduled data-reprocessing and data-intensiveanalysis tasks:
later-pass reco, AOD extraction, skimming, …
Data archiving (real+MC):custody of raw+reco & subsequently produced data
Disk storage management:fast cache to MSS, buffer for data transfer, …
Data distribution:data serving to Tier-2’s for analysis
Analysis:proficient data access via CMS+WLCG services
CMS T2 functionsCMS T2 functionsUser data analysis
Fast and detailed MC event prod
Import skimmed datasets from T1s and export MC data
Data processing for calib/aligntasks and detector studies
CMS T1 resources (nominal for average T1 in 2008):
WAN: transfer capacity ~10 Gb/s
CPU: 2.5 M-SI2k (scheduled reprocessing : analysis = 2 : 1)
Disk: 0.8 PB (~85% for analysis data serving)
MSS: 2.8 PB (losses ~tens of GB per PB stored)
CMS T2 resources (nominal for average T2 in 2008):
WAN: 1 Gb/s (at least)
CPU: 900 k-SI2k
Disk: 200 TB
T1/T2 roles and computing capacities
![Page 42: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/42.jpg)
ProdDB
CECE CE
DulcineaDulcineaDulcinea
DulcineaDulcinea
LexorDulcinea
DulcineaCondorG
CG
PANDA
RBRB
RB
ATLAS Prodsys
Different production agents for different Grid flavours
..... missing Grid Standards
![Page 43: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/43.jpg)
The LHCb Dataflow (II)
![Page 44: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/44.jpg)
The LHCb Dataflow
On-line FarmCERNTier-1s
CERNTier-1s
Tier-2s
reconstruction
pre-selectionanalysis
RAWmc data RAW data
rDST
DST+RAW TAG
calibration data
MC On-line Farm
Physics Analysis
Local Analysis
n-tuple User TAGUser DST
TAGSelected DST+RAW
Paper
CERNTier-1s
local pc
CERN
Scheduled job Chaotic job
LHCb specific
![Page 45: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/45.jpg)
Virgo - ricerca onde gravitazionali
Cascina (Pisa)
![Page 46: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/46.jpg)
• Sono previsti vari tipi di sorgenti astrofisiche che emettono ondegravitazionali con caratteristiche diverse e richiedono quindi metodi differentiper l’estrazione del segnale dal rumore.
• Il gruppo Virgo di Roma e` responsabile dell’analisi dei dati off-line per la ricerca ‘cieca’ di segnali continui emessi da stelle di neutroni asimmetricheruotanti. Questo tipo di ricerca e` estremamente pesante dal punto di vista computazionale a causa dell’enorme spazio dei parametri che deve essereesplorato.
• La potenza di calcolo a disposizione fissa la ‘profondita’ della ricerca: maggioririsorse di calcolo permettono di esplorare una porzione maggiore dello spaziodei parametri.
• Per effettuare l’analisi ‘cieca’ di 4 mesi mesi di dati e` necessaria una potenzadi calcolo almeno dell’ordine del Teraflop (≈103 CPU 2.8 GHz) su un tempo analogo.
• Questo problema di analisi e` particolarmente adatto ad essere affrontato in un ambiente di calcolo distribuito: l’intera banda di frequenze da analizzarepuo` essere divisa in un numero qualsivoglia di sotto bande, ciascunaanalizzabile indipendentemente dalle altre.
Virgo - ricerca onde gravitazionali (1/2)
![Page 47: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/47.jpg)
• I codici di analisi sono stati adattati all’ambiente grid ed e` stata creata la VO Virgo che permette agli utenti di accedere alle risorse di calcolo dei Tier-1 del CNAF e di Lione, alla piccola farm di Roma e a vari altri siti della Griglia diProduzione INFN.
• Dopo una fase di test, attualmente la griglia viene utilizzata per la parte ‘incoerente’ dell’analisi dei dati dei run di commissioning C6 e C7: oltre 30000 jobs sottomessi dall’inizio dell’anno e un cpu time di quasi 5 anni.
• Schematicamente la pipeline consiste di: una fase di pre-processamento in locale che termina con la costruzione delle cosiddette ‘peak maps’; una fase incoerentesulla griglia in cui ciascun job analizza una porzione delle peak maps producendo un lista di candidati; una fase di ‘follow-up’ coerente, in locale, in cui viene raffinatal’analisi sui candidati in coincidenza tra due o piu` set di dati.
• L’interesse per l’uso di grid si sta allargando ad altri gruppi della collaborazione: per la ricerca off-line di segnali da binarie coalescenti, per il trasferimento e gestione dei dati tra il sito di produzione e i Tier-1 di Lione e Bologna.
• Futuro(?): collaborazione/scambio dati con LIGO (OSG) per analisi distribuita
Virgo - ricerca onde gravitazionali (2/2)
![Page 48: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/48.jpg)
Studio della distribuzione della carica topologica in QCD (L. Giusti (CERN), S. Petrarca, B. Taglienti (INFN-Roma1) ) (1/2)
Scopo del lavoro e` di avere una rappresentazione accurata delladistribuzione della carica topologica ottenuta dalla definizionebasata sui fermioni di Neuberger. Lo studio, condotto su reticolidi 3 diverse dimensioni, dimostra che la distribuzione non e` gaussiana. Per averne la certezza e` necessaria una statisticamolto elevata. Il lavoro sara` presentato in forma preliminare alla conferenzaLattice2006 a fine luglio.
Dettagli del calcolo:Il programma e` tutto scritto in C, non fa uso di librerie esterneed utilizza in modo decisivo il set di istruzioni "SSE2" sviluppatoda Intel per i processori dal Pentium 4 in poi.
I 3 reticoli di dimensioni diverse richedono 250MB, 500MB e 1.1GB di RAM Per ottenere una statistica sufficiente vengono eseguiti N programmicontemporaneamente con N diversi seed iniziali; per il reticolo piu` grande N=200. Ogni programma si prefigge un numero prestabilito di passiMonte Carlo.
![Page 49: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/49.jpg)
Studio della distribuzione della carica topologica in QCD (L. Giusti (CERN), S. Petrarca, B. Taglienti (INFN-Roma1) ) (2/2)
Idealmente ognuno di questi N programmi potrebbe girare ininterrottamentefino al raggiungimento dell'obbiettivo. In pratica ogni programma fa un numerolimitato di passi, salva e riparte. Per l'input/output abbiamo utilizzato gli storageelement gentilmente concessi dai gruppi atlas, cms e virgo.
Dal 20-10-2005 al 9-6-2006 (232 giorni) sono state utilizzate su INFN-Grid circa 340.000 ore di CPU pari a 14167 giorni corrispondente ad un utilizzo medio"netto" di 61 CPU/giorno (con "netto" si intende tutto cio` che ha portato a risultati utili, quindi togliendo i job abortiti o falliti per qualsiasi motivo)
Sono stati spediti e ricevuti 19000 jobs pari a 82 job/giorno. Prevediamo di calcolare ancora per ancora 180.000 ore suddivise in 7500 job. Che cosa ci piacerebbe: 1. Poter fare dei run piu` lunghi (...... risorse condivise)2. Poter specificare a priori che ci serve una CPU con sse2 e >1GB di RAM
(problema grid)
“Killer application” per la Grid .... perche’ ?uso opportunistico di risorse INFN
![Page 50: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/50.jpg)
Conclusioni
Molti concetti della Grid ora sono piu’ chiari
Stabilita’ e affidabilita’ sono ancora un problemacapacita’ del sistema di reagire ai problemi senza interventi “umani”
Andare verso degli standardprotocolli piu’ che servizi, piu’ flessibilita’, ...
Gli esperimenti HEP (... ma non solo loro) saranno i migliori giudici della maturita’ della tecnologia
![Page 51: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/51.jpg)
The GRID distributed computing idea (1/2)
Mini ComputerMini Computer
MicrocomputerMicrocomputer
ClusterCluster
(by Christophe Jacquet)
Once upon a time……..
ComputerComputer
food chain
![Page 52: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/52.jpg)
The GRID distributed computing idea (2/2)
(by Christophe Jacquet)
…and today
GRID
![Page 53: Il progetto “GRID ” ed il calcolo dei futuri esperimenti · Digital certificate is basis of Authentication and Authorisation. Identity passed to other resources you use, where](https://reader034.vdocument.in/reader034/viewer/2022050600/5fa73e52ddbbf8386b6b1009/html5/thumbnails/53.jpg)
Domande ?
Persone coinvolte in sezione:E. Valente, M. Serra, A. BarchiesiA. De Salvo, L. Luminari (Atlas)
F.Safai, L. Barone (CMS)