I don't understand what the grandparent is saying though. Yeah, if you create a thread for every request, then you're going to be killed by the memory overhead. This isn't unique to Go, and I remember it being a problem when many noob Java programmers would spawn a thread per request before the introduction of java.nio.

The downside with Twisted, Tornado, or whatever in Python is your code isn't parallelized. It's concurrent, yes, but you aren't taking advantage of your multiple cores without forking another Python process due to GIL.

Go, Scala, Java etc. are truly multi-threaded and compile to native code from commandline or via JIT. Saying your performance advantage is due to switching from Go to Python is a spurious claim. You weren't doing it right.