heroku/lumbermill — pull request #6 by apg (2014-07-09 15:37:59+00:00)
Title: Histogram of delivery size, and batch sizes; lock avoidance

- serveDrain acquires a lot of locks for counters, which has now been
reduced to 1 per counter per batch
- We see elevated parse times for, presumably large batches, but have
no measurements in place to capture batch sizes to debug. Add
histograms for these two things.