C-extension 2 times slower than exe

[Philip Semanchuk]

On Jun 23, 2009, at 9:51 AM, Rolf Wester wrote:

> Hi,
>
> I have a C++ program that I would like to steer using Python. I made  
> the
> wrapper using swig and linked the code (without the main function)  
> into
> a shared object. My Python script loads the extension and calls a
> function of the C-extension, the rest runs entirely within the
> C-extension. For comparison I compiled the code including the main
> function with the same compilation options and linked all into an exe.
> The main function of the exe calls the same function as my Python  
> script
> does. Surprisingly the code in the Python C-extension runs twice as  
> long
> as the same code in the exe. Does anyone know what could be the reason
> for this behaviour?

If the runtime of the C/C++ code is short, the time spent initializing  
the Python interpreter might have a big impact on the runtime of the  
Python version.