I’ve been thinking about Python’s global interpreter lock (GIL) again. Since I’m a glutton for punishment and haven’t been crucified in a week, you get to hear about it too.

Has anybody thought and wrote about avoiding GIL until you need it? What I mean is creating and using GIL only when you start using code that might not be thread-safe.

So, what’s wrong with this idea?

Things that come to my mind:

• garbage collector is not thread-safe
• majority of interesting modules are not thread-safe, so there would be little ROI
• dynamic nature of Python means you can’t know in advance if you’ll need GIL and it would a bitch to fall back when you do
• …

I guess it’s just a really stupid idea.