Instructions to sleep for a second almost never result in precisely one second’s sleep. Bob Schmidt walks us through the mechanics of why. You look at the harried SI and reply, “It depends,” and you continue on your way. The SI rushes to catch up with you, and asks, “It depends on what?” And you answer, “That, too, depends,” as you continue walking.
Link: CPU Clocks and Clock Interrupts, and Their Effects on Schedulers