Dong-hee Na <donghee.n...@gmail.com> added the comment:
@vstinner @pablo @mark
On my local machine (without cpu isolation),
PR 22480 does not affect performance issues.
import pyperf
runner = pyperf.Runner()
runner.timeit(name="bench long divide",
stmt="""
for i in range(1, 256):
a = 10000 // i
""")
but I think that my benchmark does not cover the worst case.
I need to set up the CPU isolation environment but my resource is limited.
(I need a Linux machine with sufficient permission but not)
PR 22479 and PR 22480 has two sides of assumption.
PR 22479: PyNumber_FloorDivide is a heavy operation if the user thinks that
this is an unnecessary operation it should be avoided.
(In this case divide by one)
PR 22480: PyNumber_FloorDivide should process handle unnecessary operations
smartly.
In conclusion, I'd like to +1 on mark's decision.
- PR 22480: even though the divisor value is one, if the dividend is not
qualified from PyLong_CheckExact it will not get an optimization path.
So it will not cover all the 'divide by one' case and it can cause performance
issues.
- PR 22480: Always optimized if the user does not set a specific step value and
this will be same effect on PR 22492.
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<https://bugs.python.org/issue41902>
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