The future of Python immutability
nagle at animats.com
Tue Sep 8 19:45:46 CEST 2009
Steven D'Aprano wrote:
> On Tue, 08 Sep 2009 09:38:51 +0200, Hendrik van Rooyen wrote:
>> On Monday 07 September 2009 20:26:02 John Nagle wrote:
>>> Right. Tracking mutablity and ownership all the way down without
>>> making the language either restrictive or slow is tough.
>>> In multi-thread programs, though, somebody has to be clear on who
>>> what. I'm trying to figure out a way for the language, rather than the
>>> programmer, to do that job. It's a major source of trouble in threaded
>> I think that trying to make the language instead of the programmer
>> responsible for this is a ball-buster. It is unlikely to be either easy
>> or cheap. I would rather have the programmer responsible for the mental
>> model, and give her the tools to do the job with.
> That was the situation 20 years ago with memory management.
The other big point is the CPython deals with concurrency by
preventing it. This is killing performance on multi-core CPUs.
Read "http://www.dabeaz.com/python/GIL.pdf", which demonstrates
just how awful the current GIL implementation is. Adding more
CPUs slows CPython down.
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