> The goal is to have a CPU query the lock an average of 2.7 times before
> obtaining it. The number 2.7, once again, was obtained by running lots of
> tests and seeing what worked best
This is e, which shows up in similar contexts. I have a fuzzy recollection that in a situation where you want to buy something, i.e. a house or car, you know nothing about the market going in, and you need to decide to buy or not on the spot (i.e. the item disappears from the market after you've seen it), you need to sample the market (i.e. look without buying) before thinking about buying. The optimal number of items to sample is e, which translates to 3 for discrete things like houses and cars.