Python IS slow ! [was] Re: Python too slow for real world

[Markus Kohler]

Greg Ewing <greg.ewing at compaq.com> writes:

> Markus Kohler wrote:
> > 
> > From profiling python 1.5.2c I found that python's main problem is that
> > calling functions seems to be very costly.
> 
> This is just a guess, but one contributor to that might be
> the way that it packs all the arguments up into a tuple,
> and then immediately unpacks them again upon entering
> the function.

Aha ...

> 
> Also, it allocates each stack frame as a separate object.
> So that's at least two memory allocation/free operations
> per procedure call.

one could build a custom allocation routine that would preallocate
a block of memory. If the frame objects are the same size this could
eliminate most of the  allocation/deallocation time. 

> 
> A more efficient way would be to use one big stack for
> all procedure calls, and just leave the parameters on
> the stack in the usual case where a procedure with a
> fixed number of arguments is called without any keyword
> args, etc.
> 

Could you explain me a bit more about the keyword args ?
What's the problem with them ?

Markus

-- 
Markus Kohler  mailto:markus_kohler at hp.com