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bpo-44525: Specialize for calls to type and other builtin classes with 1 argument. - #29942

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markshannon merged 5 commits into
python:mainfrom
faster-cpython:specialize-calls-to-builtin-types
Dec 15, 2021
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bpo-44525: Specialize for calls to type and other builtin classes with 1 argument.#29942
markshannon merged 5 commits into
python:mainfrom
faster-cpython:specialize-calls-to-builtin-types

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@markshannon

@markshannonmarkshannon commented Dec 6, 2021•
edited by bedevere-bot
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Fidget-Spinner
Fidget-Spinner reviewed Dec 6, 2021
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The code LGTM. Interested to see the benchmark results.

@markshannon

markshannon commented Dec 7, 2021

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Benchmark results show a slight speedup, but very close to noise.

I think this is worth including because:

  1. The nbody and spectral norm benchmarks show decent speedups and have range(arg) calls in the hot parts of the benchmark, suggesting that specialization of calls to cls(one_arg) is effective.
  2. Some "real" code includes a lot of type(obj) calls (at least statically).

Fidget-Spinner
Fidget-Spinner approved these changes Dec 15, 2021
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LGTM.

Comment threadPython/ceval.c
assert(GET_CACHE()->adaptive.original_oparg == 1);
PyObject *obj = TOP();
PyObject *callable = SECOND();
DEOPT_IF(callable != (PyObject *)&PyType_Type, CALL_NO_KW);

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I don't remember if you like using the Py_IS_TYPE inline function, but just mentioning it here and leaving it up to you :).

@markshannonmarkshannonDec 15, 2021

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I'll skip on the obfuscation macro 🙂

Comment threadPython/specialize.c
return -1;
}
if (nargs == 1) {
if (tp == &PyType_Type) {

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Ditto

@markshannon

markshannon commented Dec 15, 2021

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Increases CALL_NO_KW hit rate from ~71% to ~74% on the standard benchmark suite, with only a slight increase in the miss rate.
Reduces failed specializations for calls to classes (SPEC_FAIL_CLASS) by over half.

@markshannon
markshannon merged commit 3a60bfe into python:mainDec 15, 2021
@Fidget-SpinnerFidget-Spinner mentioned this pull request Sep 9, 2022
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markshannon deleted the specialize-calls-to-builtin-types branch September 26, 2023 12:48
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