BTeV Offline Computing

1
BTeV Offline Computing

• Fast, efficient, flexible, easy-to-use facilities
  to turn Level 3 output into physics results.
• Will leverage Run II and LHC experiences.
• Must use modern computer languages (C) and
  state-of-the-art software tools.

Overall scale of the offline computing effort is
of the similar to that of one of the Run II
experiments.
2
The Physicists Picture

• Manage 2 PB/year ( 200 MB/s ) of raw data plus
  data sets derived from this.
• Final reconstruction touchups
• Most events processed only once.
• Latency hours to weeks (longer at first).
• Data selection/reduction.
• Physics analysis and simulations.
• Recycle raw data tapes every ?2 years.

3
Hardware Components

• Data archiving and access
• Many access patterns.
• Use robotic solutions developed for Run II.
• Reconstruction, Simulation and Analysis
  facilities
• Farm style with IP networking.
• Reconstruction CPU/event ? 2x Level 3.
• Desktop systems
• For use by physicists for algorithm development
  and physics analysis.
• Networks connecting all of the above.

4
CPU Requirements

• L3 Output 50 KB/event _at_ 4KHz peak rate.
• Reconstruction 200-400 ms/event (2.5 GHz CPU)
• Require 800 1600 processors
• But average rate ? 1/3 peak rate
• Require 250 500 processors
• K100 K200 _at_ 600. / (processordisk)
• Need a few times this for analysis and
  simulation, excluding desktops.
• Exploit L2/3 farm during downtime (?).

5
Software Components

• Infrastructure and framework for simulation,
  reconstruction and analysis.
• Development of algorithms for calibration,
  reconstruction, simulation and analysis.
• Data access, cluster management.
• Code management and distribution.
• Analysis tools, event visualization.
• Compilers, debuggers, databases.
• Will use C. Extensive existing software suite
  (sim/reco/anal) being wrapped/ported.

6
Basis of Estimates

• Some members of BTeV were/are involved in the
  planning for and review of Run II and LHC
  computing. Leverage this experience.
• Experience with trigger development and
  simulation work already done.
• Experience in previous experiments with high data
  volumes, E831 and E791 O(100 TB each)
  life-cycle archival storage requirements.
• Hardware Costs Extrapolate trends over last 10
  years, including Run II experience.

7
Cost Estimate

• 100 physicist-years, 50 software
  professional-years.

8
BTeV Offline Computing Summary

• Project is on the same scale as one of the Run II
  computing projects.
• Will make extensive use of experience gained in
  Run II and LHC.
• Will use C and modern software tools.
• Already have extensive software suite in mixed
  languages being ported.
• Cost (No GA, etc.) 12.4M