Add triage report for this week

triage/2025/2025-11-10.md

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+# 2025-11-11 Triage Log
+
+Mostly quiet week, with the majority of changes coming from the standard
+library work towards removal of Copy specialization
+([#135634](https://github.com/rust-lang/rust/pull/135634)).
+
+Triage done by **@simulacrum**.
+Revision range: [35ebdf9b..055d0d6a](https://perf.rust-lang.org/?start=35ebdf9ba1414456dfe1cb6a6b13ebae80e99734&end=055d0d6aaf937cc11b3d2a5b5725972723b7f3c6&absolute=false&stat=instructions%3Au)
+
+**Summary**:
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.8%  | [0.1%, 3.4%]   | 144   |
+| Regressions ❌ <br /> (secondary)  | 0.8%  | [0.1%, 2.1%]   | 76    |
+| Improvements ✅ <br /> (primary)   | -0.7% | [-1.4%, -0.4%] | 12    |
+| Improvements ✅ <br /> (secondary) | -0.3% | [-0.5%, -0.2%] | 9     |
+| All ❌✅ (primary)                 | 0.7%  | [-1.4%, 3.4%]  | 156   |
+
+3 Regressions, 1 Improvement, 7 Mixed; 3 of them in rollups
+37 artifact comparisons made in total
+
+#### Regressions
+
+feat: Use annotate-snippets by default on nightly [#148188](https://github.com/rust-lang/rust/pull/148188) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=642c19bfc3a5c1de985bf5d0cc8207ac9d22708a&end=c5e283b0d209ee6f7cd1a8cbc1974927c547f3e6&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.8%  | [0.3%, 2.9%]   | 21    |
+| Regressions ❌ <br /> (secondary)  | 0.4%  | [0.2%, 0.6%]   | 6     |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -0.0% | [-0.0%, -0.0%] | 1     |
+| All ❌✅ (primary)                 | 0.8%  | [0.3%, 2.9%]   | 21    |
+
+Likely some opportunity for improvements in annotate-snippets, but not
+particularly large or widespresad regressions in our suite.
+
+mgca: Add ConstArg representation for const items [#139558](https://github.com/rust-lang/rust/pull/139558) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=fb23dd3c6b120f0d2e55e5f2c69a464df7b35fdf&end=72b21e1a64dbbbb3b59ac7ce21363c366a894b79&stat=instructions:u)
+
+| (instructions:u)                   | mean | range        | count |
+|:----------------------------------:|:----:|:------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.2% | [0.1%, 0.5%] | 24    |
+| Regressions ❌ <br /> (secondary)  | 0.1% | [0.1%, 0.1%] | 6     |
+| Improvements ✅ <br /> (primary)   | -    | -            | 0     |
+| Improvements ✅ <br /> (secondary) | -    | -            | 0     |
+| All ❌✅ (primary)                 | 0.2% | [0.1%, 0.5%] | 24    |
+
+Required next step for `min_generic_const_args`, regressions are within range
+to be acceptable.
+
+Encode cfg trace, not its early counterpart to fix cross-crate `doc(auto_cfg)` [#148660](https://github.com/rust-lang/rust/pull/148660) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=20f1c045c46aecba6a6aeda55fe6659b26871c87&end=ab67c37c6dbea849aa3425146bfe99fb1f1d117a&stat=instructions:u)
+
+| (instructions:u)                   | mean | range        | count |
+|:----------------------------------:|:----:|:------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.2% | [0.1%, 0.3%] | 10    |
+| Regressions ❌ <br /> (secondary)  | 0.1% | [0.1%, 0.3%] | 8     |
+| Improvements ✅ <br /> (primary)   | -    | -            | 0     |
+| Improvements ✅ <br /> (secondary) | -    | -            | 0     |
+| All ❌✅ (primary)                 | 0.2% | [0.1%, 0.3%] | 10    |
+
+Bug fix. See <https://github.com/rust-lang/rust/pull/148660#issuecomment-3505481311> for details.
+
+#### Improvements
+
+Liveness: Cache the set of string constants for suggestions. [#147641](https://github.com/rust-lang/rust/pull/147641) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=0bbef557bb02e6fda8fde2c2cf9c59ee55ca40e9&end=96064126a086a8428d66e07fb3b91421bb86a512&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.9% | [-1.4%, -0.5%] | 4     |
+| Improvements ✅ <br /> (secondary) | -     | -              | 0     |
+| All ❌✅ (primary)                 | -0.9% | [-1.4%, -0.5%] | 4     |
+
+
+#### Mixed
+
+Revert "unicode_data refactors RUST-147622" [#148436](https://github.com/rust-lang/rust/pull/148436) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=35ebdf9ba1414456dfe1cb6a6b13ebae80e99734&end=f5711a55f5d5e2f942057d0f6d648dd2d8b2c37b&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | 0.2%  | [0.1%, 0.3%]   | 5     |
+| Improvements ✅ <br /> (primary)   | -0.8% | [-1.0%, -0.4%] | 3     |
+| Improvements ✅ <br /> (secondary) | -     | -              | 0     |
+| All ❌✅ (primary)                 | -0.8% | [-1.0%, -0.4%] | 3     |
+
+Nothing particularly interesting: "Performance-wish it's a wash, and this is a revert anyway."
+
+Add LLVM range attributes to slice length parameters [#148350](https://github.com/rust-lang/rust/pull/148350) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=1f880d9a1f4a331f1873829401e9d35fcfab2e36&end=20383c9f1d84eb9b9c6668a1668ef68a81eae274&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.2%  | [0.2%, 0.2%]   | 1     |
+| Regressions ❌ <br /> (secondary)  | 0.7%  | [0.1%, 2.0%]   | 29    |
+| Improvements ✅ <br /> (primary)   | -0.3% | [-0.5%, -0.1%] | 6     |
+| Improvements ✅ <br /> (secondary) | -0.3% | [-0.7%, -0.1%] | 27    |
+| All ❌✅ (primary)                 | -0.3% | [-0.5%, 0.2%]  | 7     |
+
+Primary benchmarks seeing mostly improvements. See more
+[detailed analysis](https://github.com/rust-lang/rust/pull/148350#pullrequestreview-3411957024).
+
+Rollup of 4 pull requests [#148472](https://github.com/rust-lang/rust/pull/148472) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=90b65889799733f21ebdf59d96411aa531c5900a&end=e5efc336720901420a8891dcdb67ca0a475dc03c&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | 0.5%  | [0.1%, 0.9%]   | 8     |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -0.6% | [-0.6%, -0.5%] | 3     |
+| All ❌✅ (primary)                 | -     | -              | 0     |
+
+My sense is that the large workspace crate is probably weakly (sparsely?)
+bimodal given those results. Could be an interesting thing to dig into but not
+particularly worthwhile here.
+
+Rollup of 6 pull requests [#148507](https://github.com/rust-lang/rust/pull/148507) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=c0ff72ffc4e88a2bbb69add95a4946d213996895&end=8e0b68e63cd2b7b6d18474fe6f49df6fb1570c25&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.2%  | [0.2%, 0.2%]   | 1     |
+| Regressions ❌ <br /> (secondary)  | 0.1%  | [0.1%, 0.1%]   | 2     |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -0.5% | [-0.9%, -0.1%] | 8     |
+| All ❌✅ (primary)                 | 0.2%  | [0.2%, 0.2%]   | 1     |
+
+Regressions look likely to be bimodality to me.
+
+Add LLVM realtime sanitizer [#147935](https://github.com/rust-lang/rust/pull/147935) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=bbb6f68e2888eea989337d558b47372ecf110e08&end=87f9dcd5e28a301fce81515bd4bea792444dcf29&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.1%  | [0.1%, 0.1%]   | 1     |
+| Regressions ❌ <br /> (secondary)  | 0.1%  | [0.1%, 0.1%]   | 5     |
+| Improvements ✅ <br /> (primary)   | -1.2% | [-1.2%, -1.2%] | 1     |
+| Improvements ✅ <br /> (secondary) | -1.2% | [-1.2%, -1.2%] | 1     |
+| All ❌✅ (primary)                 | -0.5% | [-1.2%, 0.1%]  | 2     |
+
+Regressions seem plausibly real, but the change doesn't seem likely to be
+further tweakable to reduce them. Marking as triaged.
+
+Rollup of 22 pull requests [#148721](https://github.com/rust-lang/rust/pull/148721) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=acda5e9f9aadac705b851935b14aa3d34a67d428&end=20f1c045c46aecba6a6aeda55fe6659b26871c87&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.8%  | [0.8%, 0.8%]   | 2     |
+| Regressions ❌ <br /> (secondary)  | 0.2%  | [0.0%, 0.3%]   | 5     |
+| Improvements ✅ <br /> (primary)   | -0.2% | [-0.3%, -0.1%] | 2     |
+| Improvements ✅ <br /> (secondary) | -0.5% | [-0.8%, -0.2%] | 2     |
+| All ❌✅ (primary)                 | 0.3%  | [-0.3%, 0.8%]  | 4     |
+
+Still searching for the cause of the regression.
+
+stop specializing on `Copy` [#135634](https://github.com/rust-lang/rust/pull/135634) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=a7b3715826827677ca8769eb88dc8052f43e734b&end=055d0d6aaf937cc11b3d2a5b5725972723b7f3c6&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.7%  | [0.1%, 3.2%]   | 110   |
+| Regressions ❌ <br /> (secondary)  | 0.8%  | [0.1%, 1.8%]   | 50    |
+| Improvements ✅ <br /> (primary)   | -0.9% | [-1.4%, -0.5%] | 2     |
+| Improvements ✅ <br /> (secondary) | -0.4% | [-0.5%, -0.1%] | 7     |
+| All ❌✅ (primary)                 | 0.7%  | [-1.4%, 3.2%]  | 112   |
+
+Expected widespread changes, this is largely a soundness fix.