gh-108223: Document --disable-gil flag in configure

[colesbury]

Adds an entry in the configure documentation for the --disable-gil flag.

• Issue: Add --disable-gil option to configure #108223

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📚 Documentation preview 📚: https://cpython-previews--108236.org.readthedocs.build/

[vstinner]

You should add a reference to the related PEP:

See :pep:`703` "Making the Global Interpreter Lock Optional in CPython".

[vstinner]

LGTM, thanks for the added doc!

[AA-Turner]

Should we add a warning admonition emphasising that this is experimental, in development, etc -- mainly to preempt a random twitter recommendation that "No GIL has now been implemented! Rebuild your Python today with --disable-gil..."

Perhaps a fear that won't materialise, though!

A

[colesbury]

I'm okay with adding whatever text you think is helpful. I expect to revisit and update this later in the development cycle based on what's actually integrated.

[AA-Turner]

Thanks Sam! Victor's simpler change I think is better for now--we don't really advertise building from source to end-users anyway, so I on reflection I think we don't need a high level of warning here.

A

[itamaro]

considering how much "nothing" this flag is currently doing, vs how much hype it could lead to -- perhaps it should be left undocumented for now?

otherwise, i'd add something like "experimental and under active development - does NOT yet provide actual GIL-less capabilities - intended for use only by contributors actively working on implementing PEP-703 and buildbots"

[vstinner]

considering how much "nothing" this flag is currently doing, vs how much hype it could lead to -- perhaps it should be left undocumented for now?

I disagree. I prefer to provide accurate documentation, because of the hype.

[vstinner]

This is always room for enhancement, but IMO that's a good start for the documentation :-) Maybe a reference documentation should be added later for any question related to NOGIL. For now, the doc points to the complete PEP.

[bedevere-bot]

There's a new commit after the PR has been approved.

@vstinner: please review the changes made to this pull request.