test_dict_inheritance_perf.py

from timeit import timeit


class A:

    def __init__(self):
        self.kwargs = {}


class B(dict):
    pass


class C:

    def __init__(self):
        self.kwargs = {}

    def __setitem__(self, key, value):
        self.kwargs[key] = value

    def __getitem__(self, key):
        return self.kwargs.get(key)


if __name__ == '__main__':

    time = timeit('A()', number=100000, globals=globals())
    print(f'A init: {time}')

    time = timeit('B()', number=100000, globals=globals())
    print(f'B init: {time}')

    time = timeit('C()', number=100000, globals=globals())
    print(f'C init: {time}')

    time = timeit('{}', number=100000, globals=globals())
    print(f'D init: {time}')

    a = A()
    time = timeit('a.kwargs["foo"] = "bar"', number=100000, globals=globals())
    print(f'A setitem: {time}')

    b = B()
    time = timeit('b["foo"] = "bar"', number=100000, globals=globals())
    print(f'B setitem: {time}')

    c = C()
    time = timeit('c["foo"] = "bar"', number=100000, globals=globals())
    print(f'C setitem: {time}')

    d = {}
    time = timeit('d["foo"] = "bar"', number=100000, globals=globals())
    print(f'D setitem: {time}')

    a = A()
    a.kwargs['foo'] = "bar"
    time = timeit('bar = a.kwargs["foo"]', number=100000, globals=globals())
    print(f'A getitem: {time}')

    b = B()
    b['foo'] = "bar"
    time = timeit('bar = b["foo"]', number=100000, globals=globals())
    print(f'B getitem: {time}')

    c = C()
    c['foo'] = "bar"
    time = timeit('bar = c["foo"]', number=100000, globals=globals())
    print(f'C getitem: {time}')

    d = {}
    d['foo'] = "bar"
    time = timeit('bar = d["foo"]', number=100000, globals=globals())
    print(f'D getitem: {time}')


# A init: 0.05380515399156138
# B init: 0.026071301006595604
# C init: 0.08211862100870349
# D init: 0.007060791002004407
# A setitem: 0.014063403010368347
# B setitem: 0.00883179999073036
# C setitem: 0.07186220100265928
# D setitem: 0.01060778700048104
# A getitem: 0.014394188998267055
# B getitem: 0.02958642499288544
# C getitem: 0.0863965710013872
# D getitem: 0.008987113993498497