1 / 10

LHCb Online

LHCb Online. & the Conditions DB. Online Usage of CondDB. Two completely independent users: The Experiment Control System Writes Online Conditions in the DB The Event Filter Farm Algorithms Need Conditions for their processing/filtering tasks. LHCb Online.

dorjan
Download Presentation

LHCb Online

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. LHCb Online & the Conditions DB

  2. Online Usage of CondDB • Two completely independent users: • The Experiment Control System • Writes Online Conditions in the DB • The Event Filter Farm Algorithms • Need Conditions for their processing/filtering tasks

  3. LHCb Online DCS Devices (HV, LV, GAS, Temperatures, etc.) Detector Channels Trigger Front End Electronics Experiment Control System Readout Network Processing/Filtering Farm Storage DAQ External Systems(LHC,Technical Services,Safety,etc)

  4. Experimental Equipment Data Handling Architecture Conf. DB ... ... PVSS PVSS PVSS PVSS PVSS Arch. PVSS PVSS PVSS PVSS ... ... . . Cond. To Offline To Offline DB

  5. Conditions DB • From the Control System point of view: • Only output • Only one interface: • from the ECS i.e. PVSS • Clients (offline algorithms) determine: • Data organization • Data format: XML (?) • Data update rate • Data could be stored in the Cond DB only if it changed by more than X or every hour • independently of the PVSS read-out rate.

  6. Online Conditions Sources • DCS • High Voltages, temperatures, pressures, etc. • DAQ & Trigger • Pedestals, thresholds, zero suppression parameters, gains, etc. • DAQ & Trigger setup parameters • EFF (Event Filter Farm) • Pedestals, Thresholds, Gain Calibration, Alignment Constants, etc. • External Systems • Accelerator data: energy, luminosity, average bunch currents, etc.

  7. Conditions Data Types • Raw DataValues read directly from hardware (ex.: HV readings, Temperatures, raw alignment data, etc.) • No Versions, no Tags (not sure yet…) • Processed DataResults of calculations done on raw data (ex.: calibration constants, alignment, etc.) • Automatic Versioning, User Tags

  8. Event Builder Switch SFC SFC SFC CPU CPU CPU . . . CPU CPU CPU . . . . . . . . . CPU CPU CPU Event Filter Farm & CondDB • The Sub Farm Controller (SFC) builds complete events • Sends each event to a free CPU for processing/filtering • A Control PC controls ~2 Sub-farms (< 50 PCs) • ~ 2000 CPUs in total

  9. Event Filter Farm CPUs • Run "Offline" Algorithms Online: • Ex: trigger, reconstruction, calibration, alignment, etc. • Within the Gaudi "Offline" Framework.(has been interfaced to PVSS for Online Monitoring and Control) • Need Conditions data: • The Control PCs will get a snapshot of the CondDB (at the Start of Run) and send it to the CPUs • This snapshot will get an ID stored in the event data to be able to reproduce the algorithm results later • Not clear yet if conditions need updating during a run…

  10. COOL Usage • Both Applications: • ECS writing Conditions for "Offline" • ECS reading conditions for the EFF • Will use the COOL API • We don't mind how COOL is implemented as long as: • The necessary functionality is available (not the case yet) • Its efficient enough • But the API seems to depend on: • RAL, SEAL, POOL, BOOST, etc. • So we'll probably setup a "stand-alone" machine running one or more Cond DB servers (prob. via DIM)

More Related