[Cython] Bindings performance issue

[Vitja Makarov]

2011/6/1 mark florisson <markflorisson88 at gmail.com>:
> On 31 May 2011 20:25, Vitja Makarov <vitja.makarov at gmail.com> wrote:
>> Hi!
>>
>> Is bindings performance issue valuable?
>>
>> $ cat bindbench.pyx
>> def wo_bindings():
>>    pass
>>
>> def outer():
>>    def inner():
>>        pass
>>    return inner
>> with_bindings = outer()
>>
>> $ python
>>>>> import timeit
>>>>> timeit.repeat('with_bindings()', setup='from bindbench import wo_bindings, with_bindings', repeat=1, number=100000000)
>> [6.169871807098389]
>>>>> timeit.repeat('wo_bindings()', setup='from bindbench import wo_bindings, with_bindings', repeat=1, number=100000000)
>> [4.609416961669922]
>>
>> PyCBindings makes it 1.3 (difference is about 15ns on my laptop) times
>> slower for CPython interpreter execution.
>> As CPython has some optimizations for CFunctions and PyCFunctions.
>>
>> Does it make sense for us? Or we can easily switch to bindings?
>>
>> --
>> vitja.
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>> http://mail.python.org/mailman/listinfo/cython-devel
>>
>
> I think switching should be fine, if you'd desperately need the speed
> you'd be calling c(p)def functions from Cython. In fact, when the
> fused cfunction will be ready it will be even slightly slower, as it
> overrides the tp_call. But perhaps that should really be made into a
> subclass...
>
> Anyway, would you use these for Python classes and module-level def
> functions (and closures) only, or would you also use them in extension
> classes? Because I found at least a bit of problem there, as extension
> class methods get 'self' passed as the first argument to the C
> function (as PyCFunctionObject.m_self), whereas methods in Python
> classes get 'self' passed in the args tuple (and the m_self is
> unused).
>

Recently I've found a problem with static methods (__new__ for
example) of inner classes (classes created inside a function, for
instance)
I think binding version should be used for all regular def functions
(defs, staticmethods, classmethods and so on).
I also think that it's better to rename binding_PyCFunction_Type to
something like CyFunctionType and make it more like PyFunction.


-- 
vitja.