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Update benchmark with Rust nightly-2025-09-01 and itoa 1.0.15 #60

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Merged
dtolnay merged 1 commit into from
Sep 1, 2025
+10 −10
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Update benchmark with Rust nightly-2025-09-01 and itoa 1.0.15 #60

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20 changes: 10 additions & 10 deletions chart/performance.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -57,23 +57,23 @@
area legend,
nodes near coords={},
] coordinates {
(0, 1)
(1, 1)
(2, 3)
(3, 5)
(4, 10)
(0, 1.3)
(1, 1.2)
(2, 3.2)
(3, 4.4)
(4, 9.1)
};
\addplot[
black,
fill=std,
area legend,
nodes near coords=\pgfmathsetmacro{\input}{{\entries}[\coordindex]}\input,
] coordinates {
(0, 16)
(1, 14)
(2, 20)
(3, 18)
(4, 24)
(0, 22)
(1, 22)
(2, 29)
(3, 27)
(4, 34)
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@dtolnay dtolnay Sep 1, 2025

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Looking more into this significant regression in libstd times, it seems to be relatively recent but spread over multiple Rust releases. Here are the recent u64::MAX timings (the others follow a similar ratio):

  • Rust 1.50–1.82: 23ns
  • Rust 1.83–1.86: 26ns
  • Rust 1.87–1.90-beta: 28ns
  • Rust 1.91-nightly: 34ns

The regression in 1.91 bisects to nightly-2025-08-29.

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@dtolnay dtolnay Sep 1, 2025

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Based on RUSTFLAGS=-Ctarget-cpu=native cargo bisect-rustc --start 2025-08-28 --end 2025-08-29 --prompt -- bench bench_std_fmt::bench_u64_max it's rust-lang/rust#145877.

};
\end{axis}
\pgfresetboundingbox\path
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