[Python-Dev] Thoughts fresh after EuroPython

[Michael Foord]

On 26/07/2010 04:42, Guido van Rossum wrote:
> On Sun, Jul 25, 2010 at 8:31 PM, Peter Portante
> <peter.a.portante at gmail.com>  wrote:
>    
>> FWIW: We use Python at Tabblo, straddled across Python 2.5.4 and 2.6.5. They
>> work. And they work well. But we make light use of threads (mostly
>> background I/O handling), and heavy use of multiple processes because we
>> can't take advantage of our multi-core systems otherwise.
>>      
> Isn't this an indication that the GIL is, in fact, not (much of) a problem?
>
> I wish those trying to get rid of the GIL well. But it may not be the
> panacea some folks are hoping for. Multi-threaded programming remains
> hard (and removing the GIL might actually make it harder).
>
> Jython and IronPython don't have a GIL, and I think PyPy may not
> either. Does anyone have experience with GIL-free programming in one
> of those?
>
>    
At Resolver Systems we created a "calculation system" that does large 
calculations on background threads using IronPython. Doing them on a 
background thread allows the ui to remain responsive. Several 
calculations could run simultaneously using multiple cores.

As the calculation operates on a large object graph (which the ui then 
needs access to in order to display it) using multiprocessing would have 
imposed a very big overhead due to serialization / deserialization (the 
program runs on windows).

Using CPython would have made the program a lot slower due to the GIL.

All the best,

Michael


-- 
http://www.ironpythoninaction.com/
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