Jack Welch-style rank-and-yank is cruel and wildly inappropriate for software developers (or any human workers, I'd argue). It encourages political blame-shifting/scapegoating games that distract from the actual work. Just having the practice is also an implicit acknowledgement that your hiring process blows.
Performance curves are just a demented and sadistic way to manage people. They're also the epitome of b-school cargo culting.