GENIE reweight table for overlays
The leading hypothesis for why ND overlay jobs are taking so long is that we are computing the GENIE reweight table for every rock event.
So the overlays give us a savings by only doing genie+geant once for each rock event, rather than once for every time it's overlayed, but we still pay the reweight table costs.
Presumably the rock singles jobs just look like:
And the mixer job looks like:
genie, geant, overlay, table
We should move to:
genie, geant, table
genie, geant, table, overlay
This requires new code in the mixer, but it should be pretty straightforward.