This reminds me of a story I read from some operating system book: Guys working on an early OS profiled the system and found that one particular routine is taki

This reminds me of a story I read from some operating system book: Guys working on an early OS profiled the system and found that one particular routine is taking a lot of CPU time. They worked hard optimizing it but found it didn't improve the overall performance at all. Turned out that routine was the idle loop of the OS. I don't remember if it was a true story or just a joke.