Exploring Phantom Traffic Jams in Your Data Flows

In the real world, there's a phenomenon called a “phantom traffic jam” or a “traffic wave.” This is when there is a standing compression wave in automobile traffic, even though there is no accident, lane closure, or other incident that would cause the traffic jam. A similar phenomenon is possible in computer networking or storage I/O, where your data can slow down for no apparent reason. In this talk, we describe when and how this effect can arise and what can be done to discover it.