09/03/2025 - 15/03/2025

10/03/2025 15:14

I did a "case study" on the parameter
(external trigger rate, number of channels, number of windows) = (4500, 16, 62)
which crashes the midas sequencer.

I found it also will crash (with this claiming all the RAM issue) even if I run this case "by hand" (i..e no sequencer). However, if I set the time threshold to something absurd (int time_threshold = 34750 which corresponds to about 1.5ms) I can construct at least some events.

Note: this is very volatile. I.e. sometimes I run with this time threshold and we create events that are too big and it errors out. It seems the issue here is the board has no pause between creating packets, meaning we can't group events by time. Instead we have to "guess" how long it takes to process the correct number of packets, and this might not even correspond to an event.

Event index: 0
Event is complete: 0
Event num packets: 882
Event reference time: 5761574
Event index: 1
Event is complete: 1
Event num packets: 992
Event reference time: 5810185
Event index: 2
Event is complete: 1
Event num packets: 992
Event reference time: 5858796
Event index: 3
Event is complete: 1
Event num packets: 992
Event reference time: 5907407
Event index: 4
Event is complete: 1
Event num packets: 993
Event reference time: 5956019
Event index: 5
Event is complete: 0
Event num packets: 991
Event reference time: 6004630
Event index: 6
Event is complete: 0
Event num packets: 481
Event reference time: 6053241
Event index: 0
Event is complete: 0
Event num packets: 882
Event reference time: 5761574
Event index: 1
Event is complete: 1
Event num packets: 992
Event reference time: 5810185
Event index: 2
Event is complete: 1
Event num packets: 992
Event reference time: 5858796
Event index: 3
Event is complete: 1
Event num packets: 992
Event reference time: 5907407
Event index: 4
Event is complete: 1
Event num packets: 993
Event reference time: 5956019
Event index: 5
Event is complete: 0
Event num packets: 991
Event reference time: 6004630
Event index: 6
Event is complete: 0
Event num packets: 481
Event reference time: 6053241

Some puzzles:

  1. This still doesn't explain the issues I saw with (3250, 16, 62), because that worked when I ran it without the sequencer by not with tht sequencer
  2. I was able to group events with time seperation of 5000 clock ticks for (28000, 32, 62) with seemingly no problems during my testing