Talk to any Python programmer long enough and eventually the topic of concurrent programming will arise—usually followed by some groans, some incoherent mumbling about the dreaded global interpreter lock (GIL), and a request to change the topic. Yet Python continues to be used in a lot of applications that require concurrent operation whether it is a small Web service or full-fledged application. To support concurrency, Python provides both support for threads and coroutines. However, there is often a lot of confusion surrounding both topics. So in the next two installments, we’re going to peel back the covers and take a look at the differences and similarities in the two approaches, with an emphasis on their low-level interaction with the system. The goal is simply to better understand how things work in order to make informed decisions about larger libraries and frameworks.
