[C++-sig] Am I crazy or is it my computer?

[Matthew Scouten]

Sorry apparently I can not write right today make that first paragraph:
The you seem to be saying that the problem is the GIL rather than
Boost::Python itself. I am already making sure to acquire the GIL before I
call into python. Here is an example of a callback wrapper:

On 11/1/07, Matthew Scouten <matthew.scouten at gmail.com> wrote:
>
> The you seem to be saying that the problem is the GIL rather than the
> problem is with the GIL rather than Boost::Python itself.  Does the I am
> already making sure to acquire the GIL before I call into python. Here is an
> example of a callback wrapper:
>
> void DataConsumer_wrapper::OnSampleCallback( int a1, int a2)
> {
>     {callback call;
>         if (override func = this->get_override("OnSampleCallback"))
>         {
>             func(a1,a2 );
>             return;
>         }
>     }// end callback call;
>     return DataConsumer::OnSampleCallback(a1,a2);
> }
>
> As I mentioned before: 'callback call' calls PyGILState_Ensure in its ctor
> and PyGILState_Release in its dtor. So I believe I have acquired the GIL
> correctly.
>
> My thought was that it was some internal data structure in boost python
> that needed locking as well. But I have the GIL before I touch any thing in
> boost::python, so nothing is getting called from python and the callback
> thread should be the only one in B::P code.
>
> Do Niall Douglas' patches do anything except manage the GIL? If not than
> maybe my problem is not thread related after all, or maybe the GIL issue is
> subtler than I thought.
>
> Is there any one on this list who knows about the guts of Boost Python? I
> would appreciate their comments.
>
>
>
>
>
>
> On 10/31/07, Ralf W. Grosse-Kunstleve <rwgk at yahoo.com> wrote:
> >
> > I don't know too much about threading, but I think
> >
> > - you still need Niall Douglas' patches
> > if your threads want
> >   to call back into Python
> > - it is fair to say that the real problem is "Python & threading",
> >
> >   mainly because of the dreaded global interpreter lock (GIL)
> >
> > Recently there has been some discussion on python-dev about getting
> >
> > rid of the GIL, but I'm not holding my breath...
> >
> >
> > IIUC, if your threads never call back into Python you don't have to
> >
> > deal with the GIL.
> > If you have to deal with the GIL I'm not surprised to see you
> > frustrated. This is something that was largely ignored in the
> > Boost.Python development (there is only so much you can hope to
> > achieve in a given amount of time...).
> >
> >
> >
> > In my work I've consciously avoided threading. Under this simplification
> > I find Boost.Python well documented and intuitive :-)
> >
> > Ralf
> >
> >
> >
> > ----- Original Message ----
> >
> > From: Matthew Scouten <matthew.scouten at gmail.com>
> >
> > To: Development of Python/C++ integration <C++-sig at python.org >
> >
> > Sent: Wednesday, October 31, 2007 1:11:27 PM
> >
> > Subject: Re: [C++-sig] Am I crazy or is it my computer?
> >
> >
> >
> > Ok, I just found this:
> > http://www.boost.org/libs/python/doc/v2/faq.html#threadsupport
> >
> >
> >
> > I seems to be saying that I can not do what I want with out patching
> > Boost::Python (or does this only apply to multiple interpretors? )
> >
> > Is this still true (please tell me it's been fixed)?
> >
> > if so, where can I get this patch and how do I apply it?
> >
> >
> >
> > I asked about multi-threading and boost python in on this list a while
> > ago, and got no answer. I took this a a "go ahead, no problems". If I am
> > being an idiot, could you tell me so? Just flame away at me so I know I've
> > been stupid.  A lot of people here actually know what they are doing. I do
> > not have that luxury.  I am finding boost python extremely complex and
> > non-intuitive.  There is also a lack of good documentation (example code is
> > nice to have, but does not constitute proper documentation all by itself).
> >
> >
> >
> >
> >
> > _______________________________________________
> > C++-sig mailing list
> > C++-sig at python.org
> > http://mail.python.org/mailman/listinfo/c++-sig
> >
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/cplusplus-sig/attachments/20071101/4642216f/attachment.htm>