00 Python timings

$ python -m timeit -v -s 'import bench_fnclass as b' 'b.as_fn()'
10 loops -> 0.000801 secs
100 loops -> 0.00851 secs
1000 loops -> 0.113 secs
10000 loops -> 7.75 secs
raw times: 7.2 7.22 7.24
10000 loops, best of 3: 720 usec per loop

$ python -V
Python 2.6.6

Finer-grained data:
$ for n in 1000 1300 1600 2100 2700 3500 4600 6000 7800 10000 13000 16000 21000; do python -m timeit -n$n -r2 -s 'import bench_fnclass as b' 'b.as_fn()'; done
1000 loops, best of 2: 101 usec per loop
1300 loops, best of 2: 112 usec per loop
1600 loops, best of 2: 121 usec per loop
2100 loops, best of 2: 136 usec per loop
2700 loops, best of 2: 149 usec per loop
3500 loops, best of 2: 167 usec per loop
4600 loops, best of 2: 206 usec per loop
6000 loops, best of 2: 289 usec per loop
7800 loops, best of 2: 413 usec per loop
10000 loops, best of 2: 733 usec per loop
13000 loops, best of 2: 1.18 msec per loop
16000 loops, best of 2: 1.64 msec per loop
21000 loops, best of 2: 2.33 msec per loop

bench_fnclass.py

def as_fn():
    class A(object):
        def __init__(self, x): self.x = x
        def f(self): return self.x
    class B(object):
        def __init__(self, x): self.x = x
        def f(self): return A(self.x+'a').f()
    class C(object):
        def __init__(self, x): self.x = x
        def f(self): return B(self.x+'b').f()
    class D(object):
        def __init__(self, x): self.x = x
        def f(self): return C(self.x+'c').f()
    for i in xrange(10):
        D('d').f()

class AsClass(object):
    class A(object):
        def __init__(self, x): self.x = x
        def f(self): return self.x
    class B(object):
        def __init__(self, x): self.x = x
        def f(self): return AsClass.A(self.x+'a').f()
    class C(object):
        def __init__(self, x): self.x = x
        def f(self): return AsClass.B(self.x+'b').f()
    class D(object):
        def __init__(self, x): self.x = x
        def f(self): return AsClass.C(self.x+'c').f()
    @staticmethod
    def go():
        for i in xrange(10):
            AsClass.D('d').f()