"I suspect though, CPU clock ticks are measured in nanoseconds or something smaller than a millisecond so this while-loop shouldn't miss its exit criteria on an

"I suspect though, CPU clock ticks are measured in nanoseconds or something smaller than a millisecond so this while-loop shouldn't miss its exit criteria on any modern machine." It's not a busy-wait. What matters is not CPU clock ticks, but how quickly an eligible-to-run program gets scheduled. That's still not going to be terribly long, of course.