Speed up bytes creation from list and tuple

[blhsing]

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

Linked PRs

• gh-128213: fast path for bytes creation from list and tuple #128214
• gh-128213: fast path for bytes creation from list and tuple #132590

[serhiy-storchaka]

How much does it benefit? Please show some microbenchmark results.

[blhsing]

How much does it benefit? Please show some microbenchmark results.

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:

100 loops, best of 5: 3.21 msec per loop # current
100 loops, best of 5: 2.23 msec per loop # this PR

With k=10000, a ~30% time reduction:

100 loops, best of 5: 31.7 usec per loop # current
100 loops, best of 5: 22.3 usec per loop # this PR

With k=100, a ~27% time reduction:

100 loops, best of 5: 410 nsec per loop # current
100 loops, best of 5: 299 nsec per loop # this PR

[sergey-miryanov]

@blhsing @eendebakpt Is there anything else we still need to do?

[eendebakpt]

@blhsing @eendebakpt Is there anything else we still need to do?

Yes. There is a free-threading bug and potentially a performance gain. The PR #132590 is ready for review.