On Fri, Apr 12, 2024 at 4:54 PM Aoife Moloney <amoloney@xxxxxxxxxx> wrote: > > Wiki - https://fedoraproject.org/wiki/Changes/Python_built_with_gcc_O3 > Discussion.fpo - > https://discussion.fedoraproject.org/t/f41-change-proposal-python-built-with-gcc-03-self-contained/112743 > > > This is a proposed Change for Fedora Linux. > This document represents a proposed Change. As part of the Changes > process, proposals are publicly announced in order to receive > community feedback. This proposal will only be implemented if approved > by the Fedora Engineering Steering Committee. > > > > == Summary == > Instead of [https://docs.fedoraproject.org/en-US/packaging-guidelines/#_compiler_flags > Fedora's default `-O2` compiler flag], we will use `-O3` to build > CPython. > This only impacts the interpreter and Python standard library, not any > 3rd party extension modules built as RPM or on developer machines. > This aligns with the way Python is built upstream. > According to our performance measurements, it makes Python > significantly faster (pyperformance geometric mean: 1.04x faster). > > == Owner == > * Name: [[User:churchyard|Miro Hrončok]] > * Email: mhroncok@xxxxxxxxxx > > > == Detailed Description == > > We will replace the `-O2` compiler flag with `-O3` when building the > python3.13 package. This change may be backported to older Pythons if > desired. [[Changes/Python3.13|Python 3.13 should be the main Python > version in Fedora 41+]]. > > The [https://docs.fedoraproject.org/en-US/packaging-guidelines/#_compiler_flags > Fedora packaging guidelines] about compiler flags explicitly say: > > ''> Overriding these flags for performance optimizations (for > instance, `-O3` instead of `-O2`) is generally discouraged. If you can > present benchmarks that show a significant speedup for this particular > code, this could be revisited on a case-by-case basis.'' > > This change proposal presents such benchmarks and a case for Python to > use `-O3`. > > This change is limited to CPython interpreter and extension modules > from the Python standard library only thanks to > [[Changes/Python_Extension_Flags_Reduction]] (since Fedora 39). Other > Python extension modules will remain bulidng as before, e.g. in RPM > packages, they will still be built with `-O2`, unless Fedora changes > that globally. The extension modules built with `-O2` still work with > Python built with `-O3`. I would like for us to consider evaluating a global change to -O3. I am not convinced that there's a good reason anymore to remain at -O2. If we get this kind of benefit from Python, I would be interested in seeing what we'd get elsewhere. -- 真実はいつも一つ！/ Always, there's only one truth! -- _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
