bpo-46944: use FASTCALL calling convention in generator.throw

[kumaraditya303]

https://bugs.python.org/issue46944

[corona10]

@kumaraditya303 Can you provide the benchmark?

[kumaraditya303]

@kumaraditya303 Can you provide the benchmark?

@corona10
Micro Benchmark (I used pyperf):

import pyperf

runner = pyperf.Runner()
runner.timeit(name="bench throw",
              stmt="g.throw(TypeError)",
              setup = """
def gen():
    while True:
        try:
            yield
        except Exception:
            pass
g = gen()
g.send(None)
""")

Result:

Mean +- std dev: [base] 264 ns +- 12 ns -> [patch] 218 ns +- 12 ns: 1.21x faster

[markshannon]

OOI, why did you choose generator.throw?
There are many builtin functions that use METH_VARARGS and could be ported to METH_FASTCALL.

I don't want to discourage you, I'm just curious.
I'd like to port as many builtin functions as possible to the faster calling conventions.

[kumaraditya303]

OOI, why did you choose generator.throw?
There are many builtin functions that use METH_VARARGS and could be ported to METH_FASTCALL.

I was reading through the generator implementation and noticed that throw does not uses the fastcall calling convention so I created a PR to make it fast.

I'll find more function which are worth porting over to fastcall. Thanks for your suggestion.

[arhadthedev]

If a vararg method looks like throw(typ[,val[,tb]]), can it be remolded as throw(typ, val=None, tb=None)?

Edit: or rather throw(typ, val=None, tb=None, /)

[bedevere-bot]

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[markshannon]

Looks good