bpo-30156: Remove property_descr_get() optimization #9541
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property_descr_get() uses a "cached" tuple to optimize function
calls. But this tuple can be discovered in debug mode with
sys.getobjects(). Remove the optimization, it's not really worth it
and it causes 3 different crashes last years.
Microbenchmark:
./python -m perf timeit -v \
-s "from collections import namedtuple; P = namedtuple('P', 'x y'); p = P(1, 2)" \
--duplicate 1024 "p.x"
Result:
Mean +- std dev: [ref] 32.8 ns +- 0.8 ns -> [patch] 40.4 ns +- 1.3 ns: 1.23x slower (+23%)
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I rewrote my commit to add a NEWS entry and update the commit message. |
rhettinger
approved these changes
Oct 1, 2018
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Thanks for the review @rhettinger ;-) |
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property_descr_get() uses a "cached" tuple to optimize function
calls. But this tuple can be discovered in debug mode with
sys.getobjects(). Remove the optimization, it's not really worth it
and it causes 3 different crashes.
Microbenchmark:
./python -m perf timeit -v
-s "from collections import namedtuple; P = namedtuple('P', 'x y'); p = P(1, 2)"
--duplicate 1024 "p.x"
Result:
Mean +- std dev: [ref] 32.8 ns +- 0.8 ns -> [patch] 40.4 ns +- 1.3 ns: 1.23x slower (+23%)
https://bugs.python.org/issue30156