[Python-Dev] threading (GilState) question

[Bob Ippolito]

On Apr 10, 2005, at 2:48 PM, Michael Hudson wrote:

> James Y Knight <foom at fuhm.net> writes:
>
>> On Apr 10, 2005, at 11:22 AM, Michael Hudson wrote:
>>
>>> Bob Ippolito <bob at redivi.com> writes:
>>>
>>>> Is there a good reason to *not* call PyEval_InitThreads when using a
>>>> threaded Python?
>>>
>>> Well, it depends how expensive ones OS's locking primitives are, I
>>> think.  There were some numbers posted to the twisted list recently
>>> that showed it didn't make a whole lot of difference on some platform
>>> or other... I don't have the knowledge or the courage to make that
>>> call.
>>>
>>>> Sounds like it would just be easier to implicitly call it during
>>>> Py_Initialize some day.
>>>
>>> That might indeed be simpler.
>>
>> Here's the numbers. It looks like something changed between python 2.2
>> and 2.3 that made calling PyEval_InitThreads a lot less expensive. So,
>> it doesn't seem to make a whole lot of difference on recent versions
>> of Python.
>
> Thanks.  I see similar results for 2.3 and 2.4 on OS X (don't have 2.2
> here).
>
> It's very much a guess, but could this patch:
>
> [ 525532 ] Add support for POSIX semaphores
>
> be the one to thank?

No, Mac OS X doesn't implement POSIX semaphores.

-bob