[issue41262] Convert memoryview to Argument Clinic

[Serhiy Storchaka]

Serhiy Storchaka <storchaka+cpython at gmail.com> added the comment:

I do not have other benchmarks. memoryview was just one of few builtins which still use PyArg_ParseTupleAndKeywords() and I know how inefficient it is. Since Argument Clinic was already used for memoryview.hex() I did not see problems with converting the rest of memoryview methods to Argument Clinic.

Microbenchmarks:

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "b = b'abcdefgh'" "memoryview(b)"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 187 ns +- 6 ns -> [/home/serhiy/py/cpython-release2/python] 144 ns +- 4 ns: 1.30x faster (-23%)

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "b = b'abcdefgh'" "memoryview(object=b)"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 312 ns +- 7 ns -> [/home/serhiy/py/cpython-release2/python] 210 ns +- 6 ns: 1.49x faster (-33%)

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "m = memoryview(b'abcdefgh')" "m.cast('I')"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 167 ns +- 4 ns -> [/home/serhiy/py/cpython-release2/python] 104 ns +- 2 ns: 1.60x faster (-38%)

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "m = memoryview(b'abcdefgh')" "m.cast(format='I')"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 331 ns +- 6 ns -> [/home/serhiy/py/cpython-release2/python] 153 ns +- 7 ns: 2.16x faster (-54%)

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "m = memoryview(b'abcdefgh')" "m.cast('B', (2, 2, 2))"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 229 ns +- 5 ns -> [/home/serhiy/py/cpython-release2/python] 154 ns +- 4 ns: 1.48x faster (-32%)

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "m = memoryview(b'abcdefgh')" "m.cast(format='B', shape=(2, 2, 2))"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 494 ns +- 11 ns -> [/home/serhiy/py/cpython-release2/python] 198 ns +- 5 ns: 2.49x faster (-60%)

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "m = memoryview(b'abcdefgh')" "m.tobytes()"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 90.3 ns +- 3.2 ns -> [/home/serhiy/py/cpython-release2/python] 65.8 ns +- 1.9 ns: 1.37x faster (-27%)

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "m = memoryview(b'abcdefgh')" "m.tobytes('C')"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 183 ns +- 6 ns -> [/home/serhiy/py/cpython-release2/python] 129 ns +- 4 ns: 1.41x faster (-29%)

$ ./python -m pyperf timeit -q --compare-to=../cpython-release/python -s "m = memoryview(b'abcdefgh')" "m.tobytes(order='C')"
Mean +- std dev: [/home/serhiy/py/cpython-release/python] 340 ns +- 11 ns -> [/home/serhiy/py/cpython-release2/python] 174 ns +- 5 ns: 1.96x faster (-49%)

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<https://bugs.python.org/issue41262>
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