Move Interface hashing and comparison to C; 2.5 to 15x speedup in micro benchmarks

Included benchmark numbers:

Current master, Python 3.8:

.....................
contains (empty dict): Mean +- std dev: 198 ns +- 5 ns
.....................
contains (populated dict): Mean +- std dev: 197 ns +- 6 ns
.....................
contains (populated list): Mean +- std dev: 53.1 us +- 1.2 us

This code:

.....................
contains (empty dict): Mean +- std dev: 77.9 ns +- 2.3 ns
.....................
contains (populated dict): Mean +- std dev: 78.4 ns +- 3.1 ns
.....................
contains (populated list): Mean +- std dev: 3.69 us +- 0.08 us

So anywhere from 2.5 to 15x faster. Not sure how that will translate to
larger benchmarks, but I'm hopeful.

It turns out that messing with ``__module__`` is nasty, tricky
business, especially when you do it from C. Everytime you define a new
subclass, the descriptors that you set get overridden by the type
machinery (PyType_Ready). I'm using a data descriptor and a meta class
right now to avoid that but I'm not super happy with that and would
like to find a better way. (At least, maybe the data part of the
descriptor isn't necessary?) It may be needed to move more code into
C, I don't want a slowdown accessing ``__module__`` either; copying
around the standard PyGetSet or PyMember descriptors isn't enough
because they don't work on the class object (so
``classImplements(InterfaceClass, IInterface)`` fails).

1 files changed, 42 insertions, 0 deletions

diff --git a/benchmarks/micro.py b/benchmarks/micro.py
new file mode 100644
index 0000000..0494b56
--- /dev/null
+++ b/benchmarks/micro.py
@@ -0,0 +1,42 @@
+import pyperf
+
+from zope.interface import Interface
+from zope.interface.interface import InterfaceClass
+
+ifaces = [
+    InterfaceClass('I' + str(i), (Interface,), {})
+    for i in range(100)
+]
+
+INNER = 1000
+
+def bench_in(loops, o):
+    t0 = pyperf.perf_counter()
+    for _ in range(loops):
+        for _ in range(INNER):
+            o.__contains__(Interface)
+
+    return pyperf.perf_counter() - t0
+
+runner = pyperf.Runner()
+
+runner.bench_time_func(
+    'contains (empty dict)',
+    bench_in,
+    {},
+    inner_loops=INNER
+)
+
+runner.bench_time_func(
+    'contains (populated dict)',
+    bench_in,
+    {k: k for k in ifaces},
+    inner_loops=INNER
+)
+
+runner.bench_time_func(
+    'contains (populated list)',
+    bench_in,
+    ifaces,
+    inner_loops=INNER
+)