[issue46235] Do all ref-counting at once for sequence multiplication

[Dennis Sweeney]

Dennis Sweeney <sweeney.dennis650 at gmail.com> added the comment:

Hm... the effects are completely different on GCC. This is with --enable-optimizations and GCC on WSL:

Slower (29):
- tuple(range(100)) * 10: 1.22 us +- 0.02 us -> 2.29 us +- 0.05 us: 1.87x slower
- tuple(range(100)) * 2: 345 ns +- 7 ns -> 629 ns +- 5 ns: 1.82x slower
- tuple(range(1000)) * 2: 3.03 us +- 0.06 us -> 5.32 us +- 0.05 us: 1.76x slower
- tuple(range(10)) * 100: 1.25 us +- 0.08 us -> 2.18 us +- 0.03 us: 1.74x slower
- tuple(range(10)) * 1000: 12.9 us +- 0.2 us -> 20.8 us +- 0.2 us: 1.61x slower
- tuple(range(100)) * 100: 13.0 us +- 0.2 us -> 20.9 us +- 0.1 us: 1.60x slower
- tuple(range(100)) * 1000: 138 us +- 2 us -> 211 us +- 2 us: 1.52x slower
- ("Python", "Perl") * 1000: 3.18 us +- 0.03 us -> 4.69 us +- 0.03 us: 1.47x slower
- tuple(range(100)) * 10000: 1.52 ms +- 0.02 ms -> 2.21 ms +- 0.02 ms: 1.45x slower
- tuple(range(10)) * 10000: 148 us +- 7 us -> 211 us +- 2 us: 1.43x slower
- tuple(range(1000)) * 10: 15.9 us +- 0.4 us -> 22.3 us +- 0.2 us: 1.40x slower
- ("Python", "Perl") * 10000: 33.8 us +- 0.8 us -> 46.5 us +- 0.6 us: 1.38x slower
- ("Python", "Perl") * 100: 428 ns +- 9 ns -> 577 ns +- 6 ns: 1.35x slower
- tuple(range(1000)) * 100: 167 us +- 2 us -> 218 us +- 2 us: 1.30x slower
- tuple(range(10)) * 2: 85.5 ns +- 3.9 ns -> 111 ns +- 3 ns: 1.30x slower
- (None,) * 100: 306 ns +- 4 ns -> 396 ns +- 3 ns: 1.29x slower
- tuple(range(1000)) * 1000: 1.78 ms +- 0.03 ms -> 2.27 ms +- 0.02 ms: 1.27x slower
- (None,) * 1000: 2.66 us +- 0.02 us -> 3.25 us +- 0.03 us: 1.22x slower
- tuple(range(10)) * 10: 236 ns +- 17 ns -> 287 ns +- 2 ns: 1.22x slower
- tuple(range(1000)) * 10000: 23.2 ms +- 0.4 ms -> 28.1 ms +- 0.3 ms: 1.21x slower
- ("Python", "Perl") * 10: 88.6 ns +- 2.7 ns -> 106 ns +- 3 ns: 1.19x slower
- (None,) * 10000: 27.5 us +- 0.3 us -> 31.5 us +- 0.2 us: 1.14x slower
- ("Python", "Perl") * 2: 48.9 ns +- 0.6 ns -> 54.7 ns +- 0.8 ns: 1.12x slower
- (None,) * 10: 63.4 ns +- 1.7 ns -> 70.0 ns +- 0.6 ns: 1.10x slower
- (None,) * 2: 46.7 ns +- 0.5 ns -> 49.8 ns +- 0.5 ns: 1.06x slower
- list(range(10)) * 2: 73.5 ns +- 1.2 ns -> 76.6 ns +- 2.3 ns: 1.04x slower
- [None] * 10: 58.1 ns +- 0.7 ns -> 60.3 ns +- 0.7 ns: 1.04x slower
- ["Python", "Perl"] * 2: 56.1 ns +- 0.6 ns -> 57.4 ns +- 0.9 ns: 1.02x slower
- [None] * 2: 51.9 ns +- 0.5 ns -> 52.3 ns +- 0.5 ns: 1.01x slower

Faster (18):
- list(range(100)) * 10000: 1.98 ms +- 0.33 ms -> 953 us +- 14 us: 2.08x faster
- list(range(1000)) * 100: 168 us +- 2 us -> 86.8 us +- 0.9 us: 1.93x faster
- list(range(1000)) * 10: 15.9 us +- 0.2 us -> 8.40 us +- 0.13 us: 1.89x faster
- list(range(100)) * 100: 13.1 us +- 0.2 us -> 7.41 us +- 0.09 us: 1.77x faster
- list(range(1000)) * 1000: 1.80 ms +- 0.05 ms -> 1.04 ms +- 0.04 ms: 1.73x faster
- list(range(100)) * 1000: 140 us +- 2 us -> 82.2 us +- 4.9 us: 1.70x faster
- list(range(1000)) * 10000: 26.0 ms +- 0.6 ms -> 15.4 ms +- 0.3 ms: 1.69x faster
- ["Python", "Perl"] * 10000: 33.8 us +- 0.3 us -> 21.2 us +- 0.2 us: 1.59x faster
- ["Python", "Perl"] * 1000: 3.41 us +- 0.03 us -> 2.17 us +- 0.02 us: 1.57x faster
- list(range(10)) * 1000: 12.2 us +- 0.2 us -> 8.11 us +- 0.21 us: 1.51x faster
- list(range(10)) * 10000: 136 us +- 2 us -> 91.7 us +- 1.0 us: 1.49x faster
- list(range(10)) * 100: 1.19 us +- 0.10 us -> 806 ns +- 15 ns: 1.47x faster
- list(range(1000)) * 2: 3.05 us +- 0.07 us -> 2.08 us +- 0.04 us: 1.46x faster
- list(range(100)) * 10: 1.17 us +- 0.03 us -> 850 ns +- 16 ns: 1.38x faster
- ["Python", "Perl"] * 100: 440 ns +- 8 ns -> 325 ns +- 5 ns: 1.35x faster
- list(range(10)) * 10: 172 ns +- 2 ns -> 148 ns +- 2 ns: 1.16x faster
- list(range(100)) * 2: 320 ns +- 19 ns -> 289 ns +- 3 ns: 1.11x faster
- ["Python", "Perl"] * 10: 85.0 ns +- 3.1 ns -> 79.7 ns +- 2.4 ns: 1.07x faster

Benchmark hidden because not significant (3): [None] * 100, [None] * 1000, [None] * 10000

Geometric mean: 1.01x slower

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue46235>
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