A Summary of CHEP 2007

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1

A Summary of CHEP 2007

Dmitry Emeliyanov, RAL PPD

Victoria, BC,
Canada,

2
-
7 Sept. 2007

2
/24

CHEP’07 : The conference


Expected
Audience:


attract 500
people


90% from
outside of
Canada


25% from US


Total: 474

3
/24

CHEP’07: Some statistics


429 abstracts submitted with 1208 authors


29 plenary talks and 7 parallel tracks:

4
/24

Selected topics


Status of the LHC and experiments


Multi
-
core CPUs and HEP software: news from Intel and
view from CERN


Online computing: Trigger and DAQ activities in LHC
experiments and beyond


All presentations are available in Indico:


http://indico.cern.ch/conferenceTimeTable.py?confId=3580


papers

will be published in Journal of Physics Conference
Series

5
/24

General LHC schedule

T. Virdee (CERN/Imperial)


Engineering run originally foreseen at end 2007 now precluded by
delays in installation and equipment commissioning


450 GeV operation now part of normal setting up procedure for beam
commissioning to high
-
energy


General schedule has been revised, accounting for inner triplet repairs
and their impact on sector commissioning


All technical systems commissioned to 7 TeV operation, and machine
closed April 2008


Beam commissioning starts May 2008


First collisions at 14 TeV c.m. July 2008


Luminosity evolution will be dominated by our confidence in the
machine protection system and by the ability of the detectors to
absorb the rates.


No provision in success
-
oriented schedule for major mishaps, e.g.
additional warm
-
up/cooldown of sector

6
/24

LHC experiments status


Construction essentially completed


Installation is very advanced
-

beam pipes closed end
March 2008


Test beam and commissioning work already carried out
gives confidence that detectors will behave as expected


Commissioning using cosmics with more and more
complete setups (complexity and functionality)


using final readout, trigger and DAQ, software and computing
systems


Computing, Software & Analysis 24/7 Challenges, Dress
Rehearsals @50% of 2008 expectation by end of 2007.


Preparations for the rapid extraction of physics being made


By spring 2008 experiments will be in 2008 configurations,
fields ON, taking cosmics

T. Virdee (CERN/Imperial)

7

Addressing Future HPC Demand
with Multi
-
core Processors


Stephen S. Pawlowski

Intel Senior Fellow

GM, Architecture and Planning

CTO, Digital Enterprise Group

September 5, 2007

8

Accelerating Multi
-

and Many
-
core

Performance Through Parallelism

Power delivery and management

High bandwidth memory

Reconfigurable cache

Scalable fabric

Fixed
-
function units

Big Core

Core

Core

Core

Core

Core

Core

Core

Core

Core

Big Core

9

Addressing Memory Bandwidth

Bringing Memory Closer to the Cores

Package

DRAM

CPU

Heat
-
sink

Last Level
Cache

Fast DRAM

Memory on Package

*Future Vision, does not represent real Intel product

3D Memory Stacking

Package

Si Chip

Si Chip

10

5 September 2007

CHEP Plenary
-

SJ

10

How good is the match
between LHC software and
current/future processors?



Sverre Jarp

CERN openlab CTO

CHEP 2007

5 September 2007

11

Implications of Moore

s law


Initially the processor was simple


Modest frequency; Single instruction issue; In order;
Tiny caches; No hardware multithreading or multi
-
core; No major problems with cooling


Since then:


Frequency scaling (from 150 MHz to 3 GHz)


Multiple execution ports, wide execution (SSE)


Out
-
of
-
order execution, larger caches


Multithreading, Multi
-
core


Heat


12

HEP Software Profile


Our memory usage:


Today, we need 2


4 GB per single
-
threaded process.


In other words, a dual
-
socket server needs at least:


Single core: 4
-

8 GB, Quad core: 16
-

32 GB


Future 16
-
way CPU: 64


128 GB, 64
-
way CPU: 256


512 GB


“We have floating point work wrapped in
‘if/else’ logic”


Overall estimate: 50% is floating point


Our LHC programs typically issue (on average)
only 1 instruction per cycle


This is very low!


Core 2 architecture can handle 4 instructions


Each SSE instruction can operate on 128 bits (2 doubles)


“our LHC programs typically utilizes only 1
instruction per CPU clock cycle (= 1/8 of
maximum)”

“We are not getting out of first gear”


13

Recommendations


Industry will bombard us with new designs
based on multi
-
billion transistor budgets


Hundreds of cores


Multiple threads per core


Unbelievable floating
-
point performance


Clearly, the emphasis
now

is to get LHC started
and there is plenty of compute power


across the Grid.


If we want to extract (much) more


compute
-
power out of new chip


generations


Try to increase the Instruction Level Parallelism


Investigate “intelligent” multithreading


Reduce our overall memory footprint

Reentrant

code

Magnetic

field

Physics

processes

Global

data

Event

specific

data

Core 0

Event
-

specific

data

Core 1

Event
-

specific

data

Core 2

Event
-

specific

data

Core 3

14

Online Computing:

CPU farms for high
-
level triggering;

Farm configuration and run control;

Describing and managing configuration data and conditions
databases;

Online software frameworks and tools; online calibration procedures


48 abstracts total: 27 oral presentations / 21 posters


By experiments:


38 LHC / 10 non
-
LHC experiment or generic


ALICE: 4


ATLAS: 15


CMS: 14


LHCb: 5


15


Data Acquisition at the LHC experiments

Plenary talk by Sylvain CHAPELAND (CERN

)

16



Alea iacta est




All fundamental choices are made


All use commercial components wherever possible


All based on powerful LAN technology and PC server
farms


Installation is progressing rapidly


Status reports:



Integration of the Trigger and Data Acquisition
Systems in ATLAS




Commissioning of the ALICE Data Acquisition
System



Commissioning and cosmics running


Commissioning of larger and larger slices has started in all 4 experiments


Large scale and Cosmic (ATLAS) tests look already very promising


Extremely valuable feedback


require customized settings / algorithms


LHC Experiments: Trigger and DAQ
Status

17

Combined Cosmic run in June 2007

17

In June we had a 14 day
combined cosmic run with no
magnetic field.

Included following systems:


Muons


RPC
(~1/32)
,


MDT
(~1/16),



TGC
(~1/36)

Calorimeters



EM (LAr )
(~50%)

&

Hadronic (Tile)
(~75%)

Tracking


Transition
Radiation Tracker (TRT)
(~6/32 of the barrel of the final
system)

Only systems missing are the
Silicon strips and pixels and
the muon system CSCs

From “The ATLAS
Trigger Commissioning
with Cosmic rays”

18

Trigger steering


Sophisticated frameworks for high level
trigger steering have been developed



Lightweight (caching of calculations (ATLAS))


Work both offline and online


Use a data
-
base for configurations (CMS)


Ready to be given to non
-
expert physicists!



The ATLAS High Level Trigger Steering




High Level Trigger Configuration and Handling of
Trigger Tables in the CMS Filter Farm




19

Data Quality Monitoring


Essential for commissioning and running


Works also with

offline


data


Standalone viewers vs plug
-
ins (e.g. web CMS)


Databases are used to store histograms or to
describe them (LHCb)


Reports from all four experiments:



The ALICE
-
LHC Online Data Quality Monitoring
Framework





A software framework for Data Quality Monitoring in
ATLAS




CMS Online Web Based Monitoring




Online Data Monitoring in the LHCb experiment


20

Slow and Run Controls


Slow and run
-
control face huge numbers of elements ~ O(10
7
)


Final run
-
control is beginning to be used on wide
-
scale, scalability
has been tested. Configuration stored in RDBMS (ALICE, CMS,
LHCb) or as objects (ATLAS)


All run
-
controls support partitioning and use finite state machines



The ATLAS DAQ System Online Configurations
Database Service Challenge




The Run Control and Monitoring System of the CMS
Experiment



Detector Control is maybe

slow


but certainly big:

The CMS Tracker
Control System

, O(50000) HV channels + O(100000) environment
sensors controlled by 5 PCs




21

TDAQ Activities Outside the LHC


Reports from mature systems



The DZERO Run 2 L3/DAQ System Performance




The PHENIX Experiment in the RHIC Run 7




The BaBar Online Detector Control System
Upgrade



And new frameworks



Multi
-
Agent Framework for Experiment Control
Systems (AFECS)



Successful upgrades (to overcome legacy
hardware), hardware extensions, high
availability, running with very small crews

22

The D0 Run II L3/DAQ System Performance


Mainly run by 3
(part
-
time) people


Heterogeneous
trigger farm scaled
up from 90 to ~ 330
nodes


Has lived reliably
through numerous
detector and
hardware upgrades


23

To summarize ...


The LHC experiments are looking forward to
seeing the first data


All core DAQ components have been tested


Good fraction of equipment is installed (except for the
filter farms and part of the DAQ network)


Integration and Commissioning are well underway


A lot of activity in trigger control and steering


Handing over to the physicists


Monitoring frameworks evolving quickly

24
/24

CHEP 2009


Will be held in Prague, Czech Republic on 21
-
27 March
2009