We add the -fno-semantic-interposition compiler/linker flag when building Python interpreters, as it provides significant performance improvement, up to 27% depending on the workload. Users will no longer be able to use LD_PRELOAD to override a symbol from libpython, which we consider a good trade off for the speedup.
-fno-semantic-interposition
+1 obviously
+1
APPROVED via the fast track with +7,0,-0
Thanks.
Metadata Update from @churchyard: - Issue tagged with: pending announcement
I abstain; that coul be a major drawback for some people.
Metadata Update from @psabata: - Issue untagged with: pending announcement
@psabata What drawback? Not being able to use LD_PRELOAD to override a symbol from libpython? We are happy to direct such users to some alternatives, such as those for memory allocations:
https://www.python.org/dev/peps/pep-0454/ https://www.python.org/dev/peps/pep-0445/
Users who actually need to use LD_PRELOAD for a symbol from libpython are expected to be hacking on Python itself and hence are very likely building their own Python anyway.
Would it be possible to expand on that? Do you refer specifically to the inability to override symbols?
Metadata Update from @churchyard: - Issue tagged with: F32, self contained change
FYI since the change has been approved in Fedora, I also proposed to make the change directly in Python upstream: https://bugs.python.org/issue38980
Announced today.
Metadata Update from @ignatenkobrain: - Issue close_status updated to: Accepted - Issue status updated to: Closed (was: Open)
Metadata Update from @bcotton: - Issue untagged with: F32 - Issue set to the milestone: Fedora 32
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