what is sweep?

I am very suspicious of anything running outside of my control, especially if it's popping up out of the blue and occupying a substantial proportion of my CPU and memory and inhibiting what I want running. Every once in a while activity monitor shows something called "sweep" running under root user. does anyone know what this is, and why it's there? How can I get rid of it, or if it's important, reschedule it to occur at a less intrusive time? I can't figure out what program it might be associated with, or what it's sweeping, but it's overheating my computer, and that is never good.