I just wanted a genlop-style build ETA predictor for my ~1500 agda modules. I already have a wrapper that launches each build subprocess in a cgroup with a memory cap, and which waits until it can lock enough memory from the parent cgroup, so I can `make -j` without fear of swapping. I expected my wrapper tool to get clever about predicting time to completion. I did *not* expect my wrapper tool to pick up the smarts to size memory cgroups even smaller based on history, thereby permitting more parallel work, concurrently. The code just kinda writes itself after a while.