import time
import sys

class A:
    def foo(self):
        print("Call A.foo!")

    def __getattr__(self, name):
        return 2

    @property
    def ppp(self):
        return 3

class B(A):
    def foo(self):
        print("Call B.foo!")


class C(B):

    def __init__(self) -> None:
        self.pps = 1

    def foo(self):
        print("Call C.foo!")


def main():
    start = time.time()
    for i in range(1, 1000000):
        pass
    end = time.time()
    peer = end - start
    c = C()
    print(f"Python version of {sys.version}")
    start = time.time()
    for i in range(1, 1000000):
        s = c.pps
    end = time.time()
    print(f"Normal getattr spend time: {end - start - peer}")
    start = time.time()
    for i in range(1, 1000000):
        s = c.ppa
    end = time.time()
    print(f"Call __getattr__ spend time: {end - start - peer}")
    start = time.time()
    for i in range(1, 1000000):
        s = c.ppp
    end = time.time()
    print(f"Call property spend time: {end - start - peer}")

if __name__ == "__main__":
    main()

Python version of 3.11.1 (main, Dec 26 2022, 16:32:50) [GCC 8.3.0]
Normal getattr spend time: 0.03204226493835449
Call __getattr__ spend time: 0.4767305850982666
Call property spend time: 0.06345891952514648

PyObject *
PyObject_GenericTryGetAttr(PyObject *obj, PyObject *name)
{
    return _PyObject_GenericGetAttrWithDict(obj, name, NULL, 1);
}

if (getattribute == NULL ||
        (Py_IS_TYPE(getattribute, &PyWrapperDescr_Type) &&
         ((PyWrapperDescrObject *)getattribute)->d_wrapped ==
         (void *)PyObject_GenericGetAttr))
        // res = PyObject_GenericGetAttr(self, name);
        res = PyObject_GenericTryGetAttr(self, name);
    else {
        Py_INCREF(getattribute);
        res = call_attribute(self, getattribute, name);
        Py_DECREF(getattribute);
    }
    if (res == NULL) {
        if (PyErr_ExceptionMatches(PyExc_AttributeError))
            PyErr_Clear();
        res = call_attribute(self, getattr, name);
    }
    Py_DECREF(getattr);
    return res;