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Investigating CSC Data Volume

Investigating CSC Data Volume. Presented by Paul Padley Work done by Antony Adair. Question, I and Others Raised. Earlier this year there was a discussion amongst some of us as to what comprises our data volume

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Investigating CSC Data Volume

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  1. Investigating CSC Data Volume Presented by Paul Padley Work done by Antony Adair.

  2. Question, I and Others Raised • Earlier this year there was a discussion amongst some of us as to what comprises our data volume • DAQ group’s specification is that our data rate over the SLINKs that send them the data should be <200MB/s • A measurement by the DAQ groups shows that we are averaging 189MB/s • How worried should we be?

  3. DAQ group slide (will zoom in on next slide)

  4. Details This is pushing up against the spec, which is what raised our concern DAQ group sees very little growth in data volume with number of vertices. They are not concerned Question: Is DAQ group correct not to be concerned?

  5. Some Observations • We read out a chamber on LCT pre-trigger in coincidence with a L1 Accept • Subjectively, looking at event displays we do not see a lot of junk hits, they correlate with LCTs • Antony and I decided to use # of LCTs as a surrogate for “data volume” • Antony has built code that can look at number of LCTs as a function of L1 Trigger bit

  6. Why LCT vs Trigger • Counting the number of LCTs vs trigger allows us to get a feel of the amount of data not correlated with an interesting muon • For example, if for single muon triggers we get lots of event with 10 LCTs, then we would suspect we have punch through or some other source of non-muon data

  7. Data Examined • Run = 180093 • Dates/Times = 2011.10.27 21:52:51 - 2011.10.28 00:07:40 • Initial Lumi = 2,592.5290527 × 10^30 cm^-2 sec^-1 • dataset = Run2011B/MinimumBias/RAW/v1 • Events I processed = 100000

  8. Observations • Number of LCTs on average scales with number of muons triggered. • We have made similar plots for all the L1 triggers and don’t see any that jump out as problematic.

  9. What about non-muon triggers> • We have also looked at non-muon triggers

  10. LCT rate in non muon triggers • Scanning through a number of non-muon triggers: • Average LCT rate of 1.7 per event seems typical • Will be some mixture of punch trhough and real muons • Note the implication, get a significant amount of data from non-muon triggers.

  11. Tentative conclusion • Our data volume is driven by the trigger menu • Muon triggers contribute in proportion to the number of muons required. • Non-muon triggers also have a significant data rate in the CSC system.

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