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Speed up bytes creation from list and tuple #128213
Description
Feature or enhancement
Proposal:
The performance of bytes creation from list and tuple can benefit from the same fast path using PySequence_Fast_ITEMS done for bytearray in gh-91149.
I have a PR ready.
Has this already been discussed elsewhere?
This is a minor feature, which does not need previous discussion elsewhere
Links to previous discussion of this feature:
No response
Activity
pythongh-128213: fast path for bytes creation from list and tuple
serhiy-storchaka commentedon Dec 25, 2024
How much does it benefit? Please show some microbenchmark results.
blhsing commentedon Dec 25, 2024
I just finished updating my benchmark results in the PR, but I'll cross-post them here:
Benchmark using
python -m timeit -n 100 -s 'a = __import__("random").choices(range(256), k=1000000)' 'bytes(a)'showing a ~31% reduction in time consumed:With
k=10000, a ~30% time reduction:With
k=100, a ~27% time reduction:sergey-miryanov commentedon Dec 1, 2025
@blhsing @eendebakpt Is there anything else we still need to do?
eendebakpt commentedon Dec 1, 2025
Yes. There is a free-threading bug and potentially a performance gain. The PR #132590 is ready for review.
gh-128213: fast path for bytes creation from list and tuple (#132590)
pythongh-128213: fast path for bytes creation from list and tuple (py…
pythongh-128213: fast path for bytes creation from list and tuple (py…