1 / 59

ACADEMIC TRAINING

ACADEMIC TRAINING. B. Panzer – CERN/IT, F. Rademakers – CERN/EP, P. Vande Vyvre - CERN/EP Academic Training CERN. Outline. Day 1 (Pierre VANDE VYVRE) Outline, main concepts Requirements of LHC experiments Data Challenges Day 2 (Bernd PANZER) Computing infrastructure Technology trends

jaimie
Download Presentation

ACADEMIC TRAINING

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ACADEMIC TRAINING B. Panzer – CERN/IT, F. Rademakers – CERN/EP, P. Vande Vyvre - CERN/EP Academic Training CERN

  2. Outline • Day 1 (Pierre VANDE VYVRE) • Outline, main concepts • Requirements of LHC experiments • Data Challenges • Day 2 (Bernd PANZER) • Computing infrastructure • Technology trends • Day 3 (Pierre VANDE VYVRE) • Trigger and Data Acquisition • Day 4 (Fons RADEMAKERS) • Simulation, Reconstruction and analysis • Day 5 (Bernd PANZER) • Computing Data challenges • Physics Data Challenges • Evolution CERN Academic Training 12-16 May 2003

  3. Trigger and Data Acquisition • Dataflow, Trigger and DAQ architectures • Trigger • Data transfer • Event building • Storage • Software framework • Simulation • Conclusion CERN Academic Training 12-16 May 2003

  4. Online dataflow Detector Digitizers Trigger Level 0,1 Front-end Pipeline/Buffer Decision Trigger Level 2 Readout Buffer Decision Subevent Buffer Event-Build. Netw. High-Level Trigger Event Buffer Decision Storage network Transient storage Permanent storage CERN Academic Training 12-16 May 2003

  5. TRG/DAQ/HLT FE FE FE LDC FEP LDC FEP LDC FEP LDC FEP GDC GDC GDC GDC PDS TDS Rare/All CTP L0, L1a, L2 BSY BSY LTU LTU L0, L1a, L2 TTC TTC FERO FERO FERO FERO FERO FERO FERO FERO Event Fragment Sub-event Event File DDL HLT Farm RORC RORC RORC RORC RORC RORC RORC RORC LDC FEP LDC FEP Load Balancing Event Building Network EDM Storage Network CERN Academic Training 12-16 May 2003

  6. ALICE Levels 4 LV-1 rate 500 Hz Readout 25 GB/s Storage 1250 MB/s CERN Academic Training 12-16 May 2003

  7. ATLAS 40 MHz ROD RoI 75 kHz 120 GB/s RRC ROB ROIB L2SV RRM L2N L2P IOM ~2 kHz ~3+3 GB/s EBN SFI DFM EFN EFP EFP EFP EFP ~ 200 Hz SFO ~ 300 MB/s Calo MuTrCh Other detectors Trigger DAQ 40 MHz D E T R/O LV L1 FE Pipelines 2.5 ms Lvl1 acc = 75 kHz Read-Out Drivers RoI data = 2% 120 GB/s D A T A F L O W H L T ~ 10 ms ROD-ROB Connection R/O S Y S T E M LVL2 RoI Builder RoI requests Read-Out Buffers L2 Supervisor L2 N/work L2 Proc Unit ROD-ROS Merger I/O Manager Lvl2 acc = ~2 kHz Dataflow Manager E V B Event Building N/work ~ sec Event Filter ~3 GB/s Sub-Farm Input Event Filter Processors Event Filter N/work EFacc = ~0.2 kHz Sub-Farm Output Levels 3 LV-1 rate 100 kHz Readout 100 GB/s Storage 100 MB/s CERN Academic Training 12-16 May 2003

  8. CMS Levels 2 LV-1 rate 100 kHz Readout 100 GB/s Storage 100 MB/s CERN Academic Training 12-16 May 2003

  9. LHCb Levels 3 LV-1 rate 1 MHz Readout 4 GB/s Storage 40 MB/s CERN Academic Training 12-16 May 2003

  10. Trigger Multi-level trigger system Reject background Select most interesting collisions Reduce total data volume CERN Academic Training 12-16 May 2003

  11. Multi-level trigger • Multi-level trigger system to optimize • Rate and granularity • System speed and size • Technology required CERN Academic Training 12-16 May 2003

  12. Trigger • Trigger Level 0 • Custom logic • Trigger Level 1 • Custom logic • Special architectures • Computing farm • Trigger Level 2 • Special architectures • Computing farm • High Level Trigger (HLT) • Computing farm • HEP specific • Home-made development • Custom building blocks • Fast but rigid • Programmable by “a few experts” • General-purpose • Home-made software • Commodity building blocks • Slow but flexible • Programmable by “all” CERN Academic Training 12-16 May 2003

  13. Trigger & Timing distribution • Transfer from TRG to electronics • One to many • Massive broadcast (100’s to 1000’s) • Optical, Digital • HEP-specific components • HEP developments CERN Academic Training 12-16 May 2003

  14. Trigger & Timing distribution CERN Academic Training 12-16 May 2003

  15. Detector & Readout Data Link (1) • Transfer from detector to DAQ • Point-to-point • Massive parallelism (100’s to 1000’s) • Interface detector/readout • Analog • HEP-specific components • Digital • HEP developments based on commodity components • Fiber Channel or Gigabit Ethernet • 2.1 or 2.5 Gb/s CERN Academic Training 12-16 May 2003

  16. Detector & Readout Data Link (2) (1-LP)250 MB/s SPI 250 MB/s 850nm 50/125um MMF OSC PM TX_CLK 2.5 Gb/s PLL TX PROTOCOL device IF_CLK OT SERDES DDL Interface RX TLK2501 PLL OT – optical transceiver PM – power monitor circuit OSC – crystal oscillator SERDES – serializer/de-serializer ID – identification memory RX_CLK APEX20KE I2C ID CERN Academic Training 12-16 May 2003

  17. Optical link source CERN Academic Training 12-16 May 2003

  18. Links Adapters • Transfer from 1 or several links to I/O bus of the memory or the computer • Many-to-one • Massive parallelism (100’s to 1000’s) • Interface detector/readout • Physical interface realized by • Custom chip • IP core (VHDL code synthesized in FPGA) CERN Academic Training 12-16 May 2003

  19. PCI evolution • Initiative of Intel • Public from the start, “imposed” to industry • Industry de-facto standard for local I/O: PCI (PCI SIG) • 1992: origin 32 bits 33 MHz 133 MBytes/s • 1993: V2.0 32 bits • 1994: V2.1 • 1996: V2.2 64 bits 66 MHz 512 MBytes/s • 1999: PCI-X 1.0 64 bits 133 MHz 1 GBytes/s • 2002: PCI-X 2.0 64 bits 512 MHz 4 Gbytes/s CERN Academic Training 12-16 May 2003

  20. Optical link destination & PCI adapter CERN Academic Training 12-16 May 2003

  21. Link and adapter performance (1) • Example of ALICE DDL and RORC • PCI 32 bits 33 MHz interface with custom chip • No local memory. Fast transfer to PC memory DDL saturated for block size above 5 kBytes: • 101 Mbytes/sec Event rate saturated for block size below 5 kBytes: • 35’000 events/sec • RORC handling overhead in LDC: 28 µsec CERN Academic Training 12-16 May 2003

  22. Link and adapter performance (2) • PCI 32 bits 66 MHz with commercial IP core • No local memory. Fast transfer to PC memory Reach 200 MB/s for block size above 2 kBytes. Total PCI load: 92 % Data transfer PCI load: 83 % CERN Academic Training 12-16 May 2003

  23. Subevent & event buffer • Baseline: • Adopt commodity component (PC) • Develop fast dual-port memories • Key parameters: • Cost/performance • Performance: memory bandwidth CERN Academic Training 12-16 May 2003

  24. PC Memory Bandwidth www.cs.virginia.eduStream v4.0 with gcc 2.96-103 } Pentium II & III machines AMD modules Xeon machine CERN Academic Training 12-16 May 2003

  25. Event Building Network (1) • Baseline: • Adopt broadly exploited standards Switched Ethernet (ALICE, ATALS, CMS) • Adopt a performant commercial product Myrinet (CMS) • Motivations for switched Ethernet: • Performance of Gigabit Ethernet switches currently available already adequate for most DAQ @ LHC • Use of commodity items: network switches and interfaces • Easy (re)configuration and reallocation of resources • Same technology also used for DAQ services CERN Academic Training 12-16 May 2003

  26. Event Building Network (2) LDC LDC LDC LDC TPC LDC TDS GDC 200 MB/s 2500 MB/s C 0 2500 MB/s 600 MB/s TRD LDC 211 224 1 7 1 14 1 8 1 14 ... 1 9 TOF-HM-PHOS Switch 22 Sector 1-2 Switch 1 Sector 35-36 Switch 18 Pixel - Strips Switch 19 Muon-PMD-TRG Switch 21 Drift Switch 20 Data Link to computing center 1250 MB/s GDC 1 GDC 4 TDS 1 TDS 2 60 MB/s 60 MB/s 1 10 1 10 ... 21 20 31 40 CERN Academic Training 12-16 May 2003

  27. Event Building Network (3) • Baseline: • Adopt broadly exploited standards Transport protocol: TCP/IP (ALICE event building) • Adopt efficient protocol Transport protocol: raw packets (LHCb TRG L1) • Motivations for TCP/IP: • Reliable and stable transport service: • Flow control handling • Lost packet handling • Congestion control • Can be verified during the ALICE Data Challenges • Industry mainstream: • Guaranteed support from present and future industrial providers: operating systems, switches, interfaces • Constant improvements CERN Academic Training 12-16 May 2003

  28. Ethernet NIC’s Performance • Fast Ethernet copper • Intel 82557, 82550, 82559 with eepro100 driver, mostly on-board • around 11 MB/s, stable • 3Com 3C980*, 3C905 with 3c59x driver, mostly on-board • around 11 MB/s, stable • Gigabit Ethernet • NetGear GA620 with acenic driver • up to 78 MB/s • 3Com 3C996 with bcm5700 or tg3 driver • up to 88 MB/s (150% of one CPU) • Intel Pro/1000* (82545EM) with e1000 driver • up to 95 MB/s (56% -> 75% of one CPU) CERN Academic Training 12-16 May 2003

  29. ADC IV: DATE Event Building (1) CERN Academic Training 12-16 May 2003

  30. ADC IV: DATE Event Building (2) Event building No recording • 5 days non-stop • 1750 MBytes/s sustained (goal was 1000) CERN Academic Training 12-16 May 2003

  31. Transient Data Storage • Transient Data Storage at point 2 before archiving (migration to tape), if any, in the computing center • Several options being tested by ALICE DAQ • Technologies • Disk attachment: • DAS: IDE (commodity), SCSI • NAS: disk server • SAN: Fiber Channel • RAID-level • Key selection criteria: cost/performance & bandwidth/box CERN Academic Training 12-16 May 2003

  32. Storage: file & record size (file cache active) CERN Academic Training 12-16 May 2003

  33. Storage: file & record size (file cache inactive) CERN Academic Training 12-16 May 2003

  34. Storage: effect of connectivity CERN Academic Training 12-16 May 2003

  35. Storage: effect of SCSI RAID CERN Academic Training 12-16 May 2003

  36. Transient Data Storage • Disk storage highly non scalable • To achieve high bandwidth performance • 1 stream, 1 device, 1 controller, 1 bus • With these conditions: • 15-20 MB/s with 7.5 kRPM IDE disks • 18-20 MB/s with 10 kRPM SCSI disks • To obtain 1.25 GB/s with commodity solutions • Footprint too big • Infrastructure cost too high • Investigate ways to obtain more compact performance • RAID (Redundant Array of Inexpensive Disks) • RAID 5, large caches, intelligent controllers • HP 3 SCSI devices: 30 MB/s with 10 kRPM disks • HP 6 SCSI devices: 40 MB/s with 10 kRPM disks • EMC 7 FCS: 50 MB/s with 10 kRPM disks (4 U) • IBM 5 FCS: 70 MB/s with 15 kRPM disks • Dot Hill SANnet II: 90 MB/s with 15 kRPM disks (2 U) CERN Academic Training 12-16 May 2003

  37. Permanent Data Storage (1) • Infinite storage • At very low cost • Must be hidden by a MSS • Critical area • Small market • Limited competition • Not (yet) commodity • Solution demonstrated since ‘02 CERN Academic Training 12-16 May 2003

  38. Permanent Data Storage (2) Tape Drive STK 9940A 10 MB/s 60 GB/Volume SCSI STK 9940B 30 MB/s 200 GB/Volume Fibre Channel Tape Library Several tape drives of both generations CERN Academic Training 12-16 May 2003

  39. Permanent Data Storage (3) CERN Academic Training 12-16 May 2003

  40. DAQ Software Framework • DAQ Software Framework • Common interfaces for detector-dependant applications • Target the complete system from the start • ALICE DATE (Data Acquisition and Test Environment) • Complete ALICE DAQ software framework: • Data-flow: detector readout, event building • System configuration, control (100’s of programs to start, stop, synchronize) • Performance monitoring • Evolving with requirements and technology • Key issues • Scalability • Very small configurations (1 PC). Used in test beams • Verified for scale of the final system (100’s of PCs) during the DC • Support and documentation CERN Academic Training 12-16 May 2003

  41. Run Control (1) CERN Academic Training 12-16 May 2003

  42. Run Control (2) State of one node CERN Academic Training 12-16 May 2003

  43. Performance monitoring - AFFAIR Fabric monitoring Round Robin DB ROOT Plots ROOT DB ROOT I/O performances LDC DATE Evt. Build. Switch DATE performances GDC ROOT I/O Files ROOT Plots for Web Disk Server CASTOR Tape Server CASTOR performances CERN Academic Training 12-16 May 2003

  44. Control Hierarchy ECS Detector Control Sys. Trigger Control Sys. DAQ Run Control Pixel Muon TPC Pixel Muon TPC Pixel Muon TPC HV GAS TPC LTC LDC 1 LDC 2 LDC 216 CERN Academic Training 12-16 May 2003

  45. Experiment Control System ECS functions • Configuration and booking • Synchronize subsytems • Operator console • Automated procedures • State Machines • Command/Status ECS config DCS TRG DAQ operators operators DCS TRG DAQ Pixel Muon TPC Pixel Muon TPC Pixel Muon TPC CERN Academic Training 12-16 May 2003

  46. Partition: Physics Run Detector A Detector B TTC Rx Det. RO DDL SIU LDC/FEP DDL DIU RORC Physics Run Partition CTP LTC LTC TTC TTC TTC TTC DDL DDL LDC/FEP LDC/FEP LDC/FEP DDL SIU LDC/FEP RORC Event Building Network GDC GDC GDC GDC GDC Storage CERN Academic Training 12-16 May 2003

  47. 2 Partitions: Physics Run & Standalone TTC Rx Det. RO DDL SIU LDC/FEP DDL DIU RORC Physics Run Partition Standalone Partition CTP LTC LTC TTC TTC TTC TTC DDL DDL LDC/FEP LDC/FEP LDC/FEP DDL SIU LDC/FEP RORC Event Building Network GDC GDC GDC GDC GDC Storage CERN Academic Training 12-16 May 2003

  48. ADC IV: DATE Scalability test CERN Academic Training 12-16 May 2003

  49. Simulation conditions/results Conditions: • 8000 Hz tot: 1600 Hz CE,MB,EL,MU • EL, MU considered rare • 50 % rejection at LDC • HLT rejects 80 % of EL • Realistic event sizes, distributions, buffer numbers, transfer rates Original count After P/F considerations Final count Huge and unacceptable decrease of EL and MU triggers due to detector busy CERN Academic Training 12-16 May 2003

  50. The problem Would like to accept all rare decays CE,MB ~50 GB/s (after P/F and time to read events into detector buffers) EL MU Detectors ~25 GB/s (limited by DDL rates) DAQ ~1.25 GB/s (after compression by 0.5) Huge reduction of the original rare decays (Electron-EL and Muon-MU) due to various backpressures PDS CERN Academic Training 12-16 May 2003

More Related