I've been following this discussion. My thoughts mostly reiterate what has already been said. There's no way to get rid of the GIL without significantly effecting single threaded performance. IMO getting rid of the GIL would require writing a mark-and-sweep algorithm. To improve performance you can do incremental (threaded) marking and detect page faults so that modified pages can be rescanned for references. The Boehm garbage collector does this (I think) but Python would need something much more custom. This type of garbage collector is VERY hard to write. Worse yet, the current implementation of Python would need a lot of rewriting.
FYI: I tried using the Boehm collector in SlickEdit and it leaked memory like crazy. I never figured out why but I suspect it had to do with it treating everything in memory as a potential pointer.
Ruby's mark-and sweep garbage collector illustrates the loss in single threaded performance and since it does its own thread scheduling, the thread performance is bad too.
As Python stands right now, its performance is excellent for single threading, the implementation is simple, it works well for the typical Python user, and using processes at least gives a work around. I like to be a perfectionist as much as the next guy but the pay back doesn't warrant the level of effort. Where's the easy button when you need oneJ
I thought you Python enthusiasts (especially Guido) might enjoy the article I just posted on the SlickEdit blog. I'm the CTO and founder of SlickEdit. I hate saying that because I'm a very humble guy but I thought you would want to know. The article is called "Comparing Python to Perl and Ruby", go to http://blog.slickedit.com/. I limited the article to a simple grammar comparison because I wanted to keep the article short. Hope you enjoy it.
Guido, I have another article written which talks about Python as well but I have not yet posted it. If you give me an email address, I will send it to you to look over before I post it. Don't give me your email address here. Instead write to email@example.com and let them know that I requested your email address.