[New-bugs-announce] [issue40151] _overlapped room for improvement

[Alexander Riccio]

New submission from Alexander Riccio <test35965 at gmail.com>:

Similarly to bpo-40145, I've tweaked build options to reduce the size of the
binary.

This patch turns on (for release builds) Whole Program Optimization, MinSpace
optimization, /Ob2 AnySuitable function inlining, /Zo (so that people can still
debug it when lots of code has been optimized out), /OPT:REF dead code
elimination, /OPT:ICF COMDAT folding, Link Time Code Generation, and DebugFull
debugging information creation.

For debug builds, it enables all of that, except instead of the MinSpace
optimization, it's only /Ob2 with custom optimization. My intent is to not
optimize any asserts or similar checks, while still getting the benefit of
dead and duplicate code elimination.


_overlapped.pyd   32 bit unimproved release size: 31KB
_overlapped.pyd   32 bit   improved release size: 29KB
                                size reduction:   -3KB
                             %  size reduction:    10%

_overlapped_d.pyd 32 bit unimproved release size: 55KB
_overlapped_d.pyd 32 bit   improved release size: 34KB
                                size reduction:  -21KB
                             %  size reduction:    38%




_overlapped.pyd   64 bit unimproved release size: 39KB
_overlapped.pyd   64 bit   improved release size: 36KB
                                size reduction:   -3KB
                             %  size reduction:     8%


_overlapped_d.pyd 64 bit unimproved release size: 74KB
_overlapped_d.pyd 64 bit   improved release size: 41KB
                                size reduction:  -33KB
                             %  size reduction:    45%


If this patch is merged, and all 7 million (estimated) Python developers update their installation, I calculate that I just saved the PSF 21GB worth of bandwidth costs :)

----------
components: Windows
messages: 365567
nosy: Alexander Riccio, paul.moore, steve.dower, tim.golden, zach.ware
priority: normal
severity: normal
status: open
title: _overlapped room for improvement
type: enhancement
versions: Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue40151>
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