[Python-ideas] the future of the GIL

[Aahz]

[excessive quoting ahead to move to python-ideas from python-3000, please
trim when you followup]

On Wed, May 09, 2007, Talin wrote:
> Greg Ewing wrote:
>> Giovanni Bajo wrote:
>>>
>>> using multiple processes cause some 
>>> headaches with frozen distributions (PyInstaller, py2exe, etc.),
>>> like those usually found on Windows, specifically because Windows
>>> does not have fork().
>>
>> Isn't that just a problem with Windows generally? I don't
>> see what the method of packaging has to do with it.
>> 
>> Also, I've seen it suggested that there may actually be
>> a way of doing something equivalent to a fork in Windows,
>> even though it doesn't have a fork() system call as such.
>> Does anyone know more about this?
> 
> I also wonder about embedded systems and game consoles. I don't know how 
> many embedded microprocessors support fork(), but I know that modern 
> consoles such as PS/3 and Xbox do not, since they have no support for 
> virtual memory at all.
> 
> Also remember that the PS/3 is supposed to be one of the poster children 
> for multiprocessing -- the whole 'cell processor' thing. You can't write 
> an efficient game on the PS/3 unless it uses multiple processors.
> 
> Admittedly, not many current console-based games use Python, but that 
> need not always be the case in the future, and a number of PC-based 
> games are using it already.
> 
> This much I agree: There's no point in talking about supporting multiple 
> processors using threads as long as we're living in a refcounting world.
> 
> Thought experiment: Suppose you were writing and brand-new dynamic 
> language today, designed to work efficiently on multi-processor systems. 
> Forget all of Python's legacy implementation details such as GILs and 
> refcounts and such. What would it look like, and how well would it 
> perform? (And I don't mean purely functional languages a la Erlang.)
> 
> For example, in a language that is based on continuations at a very deep 
> level, there need not be any "global interpreter" at all. Each separate 
> flow of execution is merely a pointer to a call frame, the evaluation of 
> which produces a pointer to another call frame (or perhaps the same 
> one). Yes, there would still be some shared state that would have to be 
> managed, but I wouldn't think that the performance penalty of managing 
> that would be horrible.

One of the primary goals of Python was/is to be an easy glue language
for C libraries.  How do you propose to handle the issue that many C
libraries use global state?
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

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