02/18/2014 Notes

DocDB Event


Craig D., Alec, Adam, Matthew, Zukai and Martin (taking notes)


  • We decided that Matthew will implement the pre-hypothesis prescale.
  • He will also implement a protection in the Send Trigger Signal module to check whether a trigger decision vector is valid before we start looping over it. This will allow us to have filters earlier in the chain return false without the Send Trigger Signal module complaining that these products do not exist. This is done by adding an IsValid check.
  • I will try to test this prescale later today or tomorrow morning.


  • We can fill Ganglia histograms with DDT now!
  • Someone needs to sit down and understand what these histograms mean when they are being filled by several processes on the same buffer node. Things did not quite add up when we compared it to the GT during the meeting.

GT Throttle

  • Andrew did some more testing on the throttle at NDOS yesterday, but somehow the rates calculated by the double ended queue did not correspond to what we saw with the Trigger Scalers.
    • It showed ~20 Hz on the scalers, but the calculation only yielded ~1 Hz.
  • Alec tested this as well and observes a similar behavior, but he confirmed that it works when you flood the GT with a few kHz. It appears that there is some order of magnitude error in the calculation.
  • Alec will try to track this issue down this afternoon and hopefully find a fix by tomorrow morning.
  • If he finds it, I will test it on NDOS tomorrow morning.

Outfitting Talk

  • We decided to request deployment with data taking.
  • If the GT throttle does not get fixed by tomorrow, we might just run during the day while an expert is around.
  • We will likely discuss this at the Outfitting meeting tomorrow, so we can let Rick and Steve make the ultimate decision on this.
  • If the GT throttle works, we will also need to pull in the NovaGlobalTrigger package into the test release.