Is Stackless Python DEAD?

Christian Tismer tismer at tismer.com
Tue Jan 15 19:48:28 CET 2002


John S. Yates, Jr. wrote:

> On 5 Nov 2001 13:53:28 GMT, amk at localhost.debian.org (A.M. Kuchling) wrote:
> 
> 
>>Not at all.  Stackless would have ramifications not just for a few
>>files in the core, but also for all the extension modules that come
>>with Python and for all the authors of third-party extension modules.
>>
> 
> Is this because those extension modules would break?  Or because they
> would be sub-optimal until they took advantage of continuations?


The extension modules do not break. But unless they support the
stackless way of calling back into an interpreter, they will
block things like microthreads.
In order to allow a C function to cooperate with Stackless, it needs
to free the C stack completely while it calls other python functions.
Everyting must be saved and restored from the frame chain.
There are cases where this is trivial, and other cases where they
are nearly impossible (aka rewrite the whole extension).

But there is no problem for C extensions which don't call back
into Python or if they do this only for short time, and you can
live with not switching coroutines/microthreads during this call.

ciao - chris

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