At work recently, I found myself trying to explain the Work-Efficiency vs Step-Efficiency tradeoff to a coworker, but when I searched for online resources to help I couldn’t find any that I liked, so I decided to take a shot at writing my own. I found this idea presented in a video lecture series about programming for GPGPUs on Youtube a while ago. However, it’s just as applicable to any form of parallel processing, from SIMD instructions running on a single CPU core up to massive clusters of thousands of computers.