[Chicago] Stackless

[Ian Bicking]

Atul Varma wrote:
> On 6/5/07, Chris McAvoy <chris.mcavoy at gmail.com> wrote:
>> This Stackless tutorial has a blurb about "concurrency is the new
>> thing" http://members.verizon.net/olsongt/stackless/why_stackless.html#concurrency-might-just-might-be-the-next-big-programming-paradigm
>> which I agree with...however...if you make a bunch of microthreads in
>> Stackless...they're not going to take advantage of multiple cores or
>> cpu's, right?  Or am I wrong about that?
> 
> I believe you are correct.  From what I understand, a lot of people
> consider the idea of a single address space being shared by two
> processors (or threads) as a recipe for disaster, as code readability
> is complicated by all the locking mechanisms and a whole new class of
> extremely hard-to-debug problems crop up as a result (deadlocks,
> starvation, race conditions, etc).
> 
> This post by Guido may help shed more light on it:
> 
>   http://mail.python.org/pipermail/python-3000/2007-May/007414.html
> 
> The bottom line, though, is that it appears as though Python isn't
> really going to improve its support for threads; rather, the
> assumption is that if a Python solution needs to take advantage of
> multiple processors, it should use multiple processes instead of
> multiple threads.

I really wish PyPy would implement green thread/processes, with 
non-shared memory.  Then you'd get really light processes that acted 
like traditional processes.  You'd need some clever copy-on-write stuff 
so that you didn't have a complete memory copy if two processes use the 
same module; otherwise the processes aren't all that light.

I've suggested this a few times, and PyPy people always say that sure, 
that would be easy; another kind of object space, I guess.  But of 
course "would be easy" and "exists" aren't the same thing, so the answer 
is never that satisfying.

I'm intrigued by this module, but haven't tried it: 
http://cheeseshop.python.org/pypi/processing

-- 
Ian Bicking | ianb at colorstudy.com | http://blog.ianbicking.org
             | Write code, do good | http://topp.openplans.org/careers