Preemptive Multithreading by using Continuations

[Mike C. Fletcher]

I think Guido _was_ interested in seeing a pre-emptive (portable) 
micro-threading system built using the current Python around the 2.2.0 
time-frame (though not generators specifically (and he seems to dislike 
continuations) IIRC), not sure if that interest ever went anywhere (I'm 
assuming no, given that I haven't heard about it since).  IIRC the 
discussion was over on python-dev cross-posted to the stackless list, so 
you could troll the archives of either for it.

Your approach is funky (pushing all processing into signal handlers).  I 
wouldn't have thought of doing that (I thought signal handlers froze the 
CPU in their code (including blocking all system threads) until they 
were finished). Out of curiosity, does the approach also pre-empt C code 
(I would think it would)?

Anyway, interesting hack. I wouldn't call what you're using 
"continuations" (at least not first-class ones such as you saw in 
Stackless 1.0), though I suppose the OS's signal-handling machinery 
could be considered a stack of open continuations.  Have fun,
Mike

Dominic wrote:

> Python continuations can easily be used for
> cooperative threading.
>
> But has anyone tried to implement
> preemptive threading by using continuations?

...

> So my question is: Has anyone
> tried or implemented a decent
> (well, everything that is better than
> my hack ;-)
> microthreading package for
> standard python?

...

_______________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://members.rogers.com/mcfletch/