LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March...
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Transcript of LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March...
![Page 1: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/1.jpg)
LHCb Upgrade Overview
ALICE, ATLAS, CMS & LHCb joint workshop on DAQChâteau de Bossey
13 March 2013Beat Jost / Cern
![Page 2: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/2.jpg)
Beat Jost, Cern
Overview
❏ A little bit of Archaeology➢ The evolution of the LHCb DAQ system with time
❏ Upgrade motivation➢ More data➢ Trigger efficiencies
❏ The System after Upgrade
2LHCb Upgrade Overview, 13 March 2013
![Page 3: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/3.jpg)
Beat Jost, Cern
Archaeology – LoI (1996)
3LHCb Upgrade Overview, 13 March 2013
❏ Very much Atlas inspired➢ Level-1 400 kHz➢ Level-2 10 kHz➢ Level-3 200 Hz
Somewhat Cute…
![Page 4: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/4.jpg)
Beat Jost, Cern
Archaeology – Techn. Proposal (1998)
4LHCb Upgrade Overview, 13 March 2013
Still two protocols (Full readout/push vs. Phased Readout/pull)
![Page 5: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/5.jpg)
Beat Jost, Cern
Archaeology – Online TDR (2001)
5LHCb Upgrade Overview, 13 March 2013
Level-1 Trigger physically a separate entity
![Page 6: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/6.jpg)
Beat Jost, Cern
Archaeology – Trigger TDR (2003)
6LHCb Upgrade Overview, 13 March 2013
Level-1 Trigger integrated in the Overall HLT framework. Still logically a separate entity
![Page 7: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/7.jpg)
Beat Jost, Cern
Archaeology – The final design (2005)
7LHCb Upgrade Overview, 13 March 2013
Read-out Network (RN)
50 GB/s
40 MB/s
Control & Monitoring
(ECS)
LAN
Detector Read-out Units (DRU)
Timing & Fast
Control (TFC)
Level-0Front-End Electronics
VELO
L0
40 MHz
1 MHz
DataRates
40 TB/s
1 TB/sFront-End Links
Switch Switch Event Distribution
Storage
Dat
a Re
ques
t
Level 0Trigger
Fixed latency 4.0 s
Event Filter Farm
Variable latency~10 ms
TRACK ECAL HCAL MUON RICH
LHCb Detector
CPU CPU
CPU CPU
Throttle
50 GB/s
DRU DRU DRU
Level-1 Trigger eliminated as a distinct entity.The ultimate simplicity.All data read out at hardware trigger speed.1MHz Readout.
Actually more like 300 MB/s
![Page 8: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/8.jpg)
Beat Jost, Cern
Why upgrade??
❏ After LS2 we want more data (factor ~10) of same or better quality i.e. more signal events➢ Need to run at higher luminosity (currently 4·1032 cm-2·s-1)➢ Aim is to operate at luminosity of 10-20·1032 cm-2·s-1
➢ BUT
➢ Thus, increasing the luminosity (keeping the trigger rate at 1 MHz) doesn’t help the hadron channels
need to increase the L0 trigger rate8
LHCb Upgrade Overview, 13 March 2013
![Page 9: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/9.jpg)
Beat Jost, Cern
What trigger rate for upgrade?
9LHCb Upgrade Overview, 13 March 2013
❏ ~20 MHz seems sufficient❏ interaction rate 30 MHz❏ Bunch crossing rate 40 MHz
❏ design for 40 MHz (maximum)to stop all discussions
![Page 10: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/10.jpg)
Beat Jost, Cern
40 MHz Readout – Implications
❏ New front-end electronics (Readout chips) for (almost) all detectors➢ Basically only detectors involved in the trigger have to change to a
lesser degree (basically modernisation)
❏ To limit number of data links from detector to event building, Zero suppression has to happen at/near the detector
❏ 40 times more trigger rate 40 times more data rate (after ZS)➢ Big challenge for readout network➢ Assuming event size 100 kB 4 TB/s aggregate bandwidth
➥ Actually: as only 30 MHz interaction rate ~3 TB/s
➢ ~40 more CPU power needed (compared to now)
❏ To cope with (prob.) staged farm installation need a LLT (Low-Level Trigger)➢ Similar to current L0 trigger, but with relaxed cuts to adjust for
available CPU power10
LHCb Upgrade Overview, 13 March 2013
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Beat Jost, Cern
Mitigation of the challenges
❏ Minimize Number of readout links➢ Zero suppression at detector
➥ Rad tolerant/hard FPGAs to implement the necessary algorithms
➢ Faster readout links➥ Currently GOL (1.6 Gb/s) GBT (3.x Gb/s)➥ Helps reducing number of links (estimated ~12000)new receiver card aggregating the detector links and interfaces to the DAQ
❏ Readout Network Bandwidth➢ Faster link technology
➥ Currently GbEthernet 10/40/100 GbEthernet or 56 GbInfiniband➥ Main questions
– Port density in switches/routers– Buffering capabilities in switches/routers
which data transfer protocols?
❏ CPU power➢ Total need typically factor 30-40 more
➥ Factor ~10 Moore’s law➥ Factor 3-4 more boxes
❏ Low-Level Trigger➢ Basically re-use the current trigger system with thresholds adapted to the rate desired
❏ New TFC (TTCGBT)❏ New interfaces (GBT) for Controls and Monitoring of FE Electronics
11LHCb Upgrade Overview, 13 March 2013
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Beat Jost, Cern
The System after LS2
12LHCb Upgrade Overview, 13 March 2013
❏ Only a very high-level architectural picture
❏ Still hope to keep a simple data transfer protocol
Read-out Network (RN)
~4TB/s
~2-3 GB/s
Control & Monitoring
(ECS)
LA
N
Detector Read-out Units (DRU)
Timing & Fast Control (TFC)
Front-End ElectronicsZero Suppression
VELO
LLT
40 MHz
x MHz
DataRates
~40 TB/s
~4 TB/s
Front-End Links
Switch Event Distribution
Storage
Dat
a R
equ
est
Low LevelTrigger
Fixed latency 4.0 s
Event Filter Farm
Variable latency
TRACK ECAL HCAL MUON RICH
LHCb Detector
CPU CPU
CPU CPU
Throttle
~4 TB/s
DRU DRU DRU
Switch
![Page 13: LHCb Upgrade Overview ALICE, ATLAS, CMS & LHCb joint workshop on DAQ Château de Bossey 13 March 2013 Beat Jost / Cern.](https://reader031.fdocuments.us/reader031/viewer/2022032723/56649d205503460f949f480e/html5/thumbnails/13.jpg)
Beat Jost, Cern
Summary
❏ The upgrade of the LHCb Online system is driven by the physics request for more/better quality data➢ Limitation is hardware trigger at given max. readout
rate
❏ The 40 MHz readout is a natural evolution of the system, but implies a lot of work/money➢ ZS at detector➢ Faster links➢ New readout Boards➢ Bigger network➢ Bigger farm
❏ In general, as always, time is on our side …
13LHCb Upgrade Overview, 13 March 2013