Highly recommend the core.py podcast if you're interested in the background, there are a few episodes that focus on the GILectomy:

-Episode 2: Removing the GIL[1]

-Episode 12: A Legit Episode[2]

[1]https://www.youtube.com/watch?v=jHOtyx3PSJQ&list=PLShJCpYUN3...

[2]https://www.youtube.com/watch?v=IGYxMsHw9iw&list=PLShJCpYUN3...