Need to improve COM performance

[Mark Hammond]

Tom Fenn wrote:

> Hello,
> 
> I'm working on an application that involves calculating some
> statistics for data produced by a commercial scientific instrument
> (ion trap mass spectrometer).  The code works, but takes longer than I
> expected to execute.  I ran the profiler on it, and got the following
> results (which are sorted on cumtime and percall).  Access to the data
> file is through a COM control provided by the manufacturer.  I've
> wrapped it using genpy, and then wrapped an easier to use class around
> the component.  If I read the profile data right, the program is
> spending 14 of its 15 minutes of execution time in the ApplyTypes
> routine from PythonCOM. Is there anything I can do to speed this up
> from within Python?  Would implementing the Python class in C++
> improve performance significantly in this case?  Happily, the
> application is spending only a few seconds in my own code.


If you look at _ApplyTypes_, you will notice it is a single line:

return self._get_good_object_(apply(self._oleobj_.InvokeTypes, (dispid, 
0, wFlags, retType, argTypes) + args), user, resultCLSID)

The time for _get_good_object_ is accounted for in the profile stats. 
The rest of the time is being spent in InvokeTypes.  - ie, in some 
*other* COM object.

ie, I think that all this is telling you is that the COM object you are 
calling is taking all the time, not your Python code.

Mark.