Just curious what is actually happening during that time? What information is it gathering, and how does NPM use it?
Many of the statistics that Orion collects (most notably interface traffic) are reported by devices as counters like "total bytes transferred". To get from "total bytes transferred" to "bytes/second" we need to gather the value of the counter once, wait a little while, then collect it again. It's like calculating your speed by watching the odometer and a stopwatch.
"Baselining" is when we gather an initial value for the counter.
