Add triage for this week

triage/2025/2025-09-07.md

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+# 2025-09-07 Triage Log
+
+Overall, a fairly neutral week with relatively few changes affecting
+performance landing.
+
+Triage done by **@simulacrum**.
+Revision range: [75ee9ffd..f13ef0d7](https://perf.rust-lang.org/?start=75ee9ffd5ed3649c0a09493057adaa8feebb2035&end=f13ef0d75d834c826c9479a5d244bcfb9891df45&absolute=false&stat=instructions%3Au)
+
+**Summary**:
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.5%  | [0.1%, 1.6%]   | 54    |
+| Regressions ❌ <br /> (secondary)  | 0.2%  | [0.0%, 0.5%]   | 54    |
+| Improvements ✅ <br /> (primary)   | -0.7% | [-5.6%, -0.1%] | 18    |
+| Improvements ✅ <br /> (secondary) | -1.5% | [-5.7%, -0.0%] | 43    |
+| All ❌✅ (primary)                 | 0.2%  | [-5.6%, 1.6%]  | 72    |
+
+1 Regression, 5 Improvements, 3 Mixed; 4 of them in rollups
+33 artifact comparisons made in total
+
+#### Regressions
+
+Rollup of 5 pull requests [#146224](https://github.com/rust-lang/rust/pull/146224) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=ad85bc524b1ad696e42061ad8338d382dffbdbe5&end=c559c4a741836c4ffa8e4f60cb9fe7e92af5298e&stat=instructions:u)
+
+| (instructions:u)                   | mean | range        | count |
+|:----------------------------------:|:----:|:------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.1% | [0.1%, 0.1%] | 2     |
+| Regressions ❌ <br /> (secondary)  | 0.2% | [0.0%, 0.3%] | 8     |
+| Improvements ✅ <br /> (primary)   | -    | -            | 0     |
+| Improvements ✅ <br /> (secondary) | -    | -            | 0     |
+| All ❌✅ (primary)                 | 0.1% | [0.1%, 0.1%] | 2     |
+
+Doc-only effects, likely from changes to std/core. Not worth digging deeper.
+
+#### Improvements
+
+cleanup and cache proof tree building [#145951](https://github.com/rust-lang/rust/pull/145951) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=f6df223ea8c0017e64ce19c99afa32c0c629142c&end=a2c8b0b92c14b02f0b3f96a0d5296f1090dc286b&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | 0.0%  | [0.0%, 0.0%]   | 1     |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -3.0% | [-5.7%, -0.1%] | 15    |
+| All ❌✅ (primary)                 | -     | -              | 0     |
+
+
+rustdoc-search: yet another stringdex optimization attempt [#145911](https://github.com/rust-lang/rust/pull/145911) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=0d6a806909f8e99ad59d3ca96dee012faf9a38e9&end=af00ff2ce62b6617ed19305ae39e135ac71d0b22&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.8% | [-6.0%, -0.1%] | 11    |
+| Improvements ✅ <br /> (secondary) | -1.0% | [-2.4%, -0.2%] | 3     |
+| All ❌✅ (primary)                 | -0.8% | [-6.0%, -0.1%] | 11    |
+
+
+resolve: Avoid finalizing extern prelude entries more than once [#144737](https://github.com/rust-lang/rust/pull/144737) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=91edc3ebccc4daa46c20a93f4709862376da1fdd&end=ad85bc524b1ad696e42061ad8338d382dffbdbe5&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.1% | [-0.1%, -0.1%] | 6     |
+| Improvements ✅ <br /> (secondary) | -1.1% | [-2.0%, -0.4%] | 8     |
+| All ❌✅ (primary)                 | -0.1% | [-0.1%, -0.1%] | 6     |
+
+
+Rollup of 5 pull requests [#146267](https://github.com/rust-lang/rust/pull/146267) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=0d0f4eac8b98133e5da6d3604d86a8f3b5a67844&end=6d5caf3a4a358c80f09ba51d71db0dbc41381992&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.1% | [-0.2%, -0.1%] | 2     |
+| Improvements ✅ <br /> (secondary) | -0.3% | [-0.7%, -0.1%] | 15    |
+| All ❌✅ (primary)                 | -0.1% | [-0.2%, -0.1%] | 2     |
+
+
+Make the allocator shim participate in LTO again [#146232](https://github.com/rust-lang/rust/pull/146232) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=6d5caf3a4a358c80f09ba51d71db0dbc41381992&end=bea625f3275e3c897dc965ed97a1d19ef7831f01&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | 0.1%  | [0.1%, 0.2%]   | 2     |
+| Improvements ✅ <br /> (primary)   | -0.9% | [-1.9%, -0.3%] | 221   |
+| Improvements ✅ <br /> (secondary) | -0.9% | [-2.2%, -0.0%] | 260   |
+| All ❌✅ (primary)                 | -0.9% | [-1.9%, -0.3%] | 221   |
+
+
+#### Mixed
+
+Rollup of 24 pull requests [#146185](https://github.com/rust-lang/rust/pull/146185) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=9385c64c95d971329e62917adc4349c8ccdbafe0&end=033c0a4742794f5608b19eb78458726596f8ec18&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.6%  | [0.1%, 1.6%]   | 39    |
+| Regressions ❌ <br /> (secondary)  | 0.2%  | [0.0%, 0.6%]   | 27    |
+| Improvements ✅ <br /> (primary)   | -0.5% | [-0.9%, -0.2%] | 12    |
+| Improvements ✅ <br /> (secondary) | -0.3% | [-0.5%, -0.1%] | 9     |
+| All ❌✅ (primary)                 | 0.3%  | [-0.9%, 1.6%]  | 51    |
+
+Regressions mostly from:
+
+- [On unused binding or binding not present in all patterns, suggest potential typo of unit struct/variant or const](https://github.com/rust-lang/rust/pull/145827)
+- [Allow inline(always) with a target feature behind a unstable feature `target_feature_inline_always`.](https://github.com/rust-lang/rust/pull/145932)
+
+Doesn't seem worth digging deeper - these are features or diagnostic
+improvements and the regressions aren't too large or two widespread.
+
+Rollup of 5 pull requests [#146192](https://github.com/rust-lang/rust/pull/146192) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=79bdc627562db90599edcf16cb166a532919a0a8&end=45b9d13b455f820c12760e0fbf6ce69110a3aeda&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.1%  | [0.1%, 0.1%]   | 1     |
+| Regressions ❌ <br /> (secondary)  | 0.3%  | [0.1%, 0.4%]   | 2     |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -0.2% | [-0.5%, -0.1%] | 7     |
+| All ❌✅ (primary)                 | 0.1%  | [0.1%, 0.1%]   | 1     |
+
+Regressions largely recovered in subsequent commits (though not in related PRs,
+so possibly spurious in the first place) and don't seem worth further followup.
+
+Rework how the codegen coordinator code handles the allocator shim [#145955](https://github.com/rust-lang/rust/pull/145955) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=45b9d13b455f820c12760e0fbf6ce69110a3aeda&end=71289c378d0a406a4f537fe4001282d19362931f&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.9%  | [0.3%, 2.0%]   | 229   |
+| Regressions ❌ <br /> (secondary)  | 0.9%  | [0.0%, 2.2%]   | 259   |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -0.2% | [-0.3%, -0.0%] | 4     |
+| All ❌✅ (primary)                 | 0.9%  | [0.3%, 2.0%]   | 229   |
+
+The regressions here are clawed back in [Make the allocator shim participate in LTO again](https://github.com/rust-lang/rust/pull/146232).