Add triage for this week

triage/2023-01-31.md

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+# 2023-01-31 Triage Log
+
+Overall a positive week, with relatively few regressions overall and a number of improvements.
+
+Triage done by **@simulacrum**.
+Revision range: [c8e6a9e8b6251bbc8276cb78cabe1998deecbed7..a64ef7d07d0411315be85a646586cb85eeb9c136](https://perf.rust-lang.org/?start=c8e6a9e8b6251bbc8276cb78cabe1998deecbed7&end=a64ef7d07d0411315be85a646586cb85eeb9c136&absolute=false&stat=instructions%3Au)
+
+**Summary**:
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.6%  | [0.6%, 0.6%]   | 1     |
+| Regressions ❌ <br /> (secondary)  | 0.3%  | [0.3%, 0.3%]   | 1     |
+| Improvements ✅ <br /> (primary)   | -0.8% | [-2.0%, -0.2%] | 27    |
+| Improvements ✅ <br /> (secondary) | -0.9% | [-1.9%, -0.5%] | 11    |
+| All ❌✅ (primary)                 | -0.8% | [-2.0%, 0.6%]  | 28    |
+
+
+2 Regressions, 4 Improvements, 6 Mixed; 2 of them in rollups
+44 artifact comparisons made in total
+
+#### Regressions
+
+Fix thin archive reading [#107360](https://github.com/rust-lang/rust/pull/107360) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=6cd6bad51fb34a0d89e97c27814041fe4d0838b5&end=252741673b9c2b06267cd3a036d77489e92f963a&stat=instructions:u)
+
+| (instructions:u)                   | mean | range        | count |
+|:----------------------------------:|:----:|:------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.4% | [0.3%, 0.6%] | 13    |
+| Regressions ❌ <br /> (secondary)  | 0.5% | [0.4%, 0.5%] | 2     |
+| Improvements ✅ <br /> (primary)   | -    | -            | 0     |
+| Improvements ✅ <br /> (secondary) | -    | -            | 0     |
+| All ❌✅ (primary)                 | 0.4% | [0.3%, 0.6%] | 13    |
+
+Revert of previous PR to fix behavior. Regressions are minor and hopefully the
+relanding of the original PR will fix them too.
+
+Use stable metric for const eval limit instead of current terminator-based logic [#106227](https://github.com/rust-lang/rust/pull/106227) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=bcb064a7f4aee705c97ce1b74beb9af0f9b5adb2&end=3cdd0197e78e2ca3403157617709bbfe18a3f0b5&stat=instructions:u)
+
+| (instructions:u)                   | mean | range        | count |
+|:----------------------------------:|:----:|:------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.3% | [0.3%, 0.4%] | 3     |
+| Regressions ❌ <br /> (secondary)  | 0.8% | [0.5%, 1.0%] | 9     |
+| Improvements ✅ <br /> (primary)   | -    | -            | 0     |
+| Improvements ✅ <br /> (secondary) | -    | -            | 0     |
+| All ❌✅ (primary)                 | 0.3% | [0.3%, 0.4%] | 3     |
+
+The new metric adds new MIR instructions, which increases the size of MIR and
+slightly hurts performance. However, this is in service of a concrete feature,
+so acceptable.
+
+
+#### Improvements
+
+use `LocalDefId` instead of `HirId` in trait resolution to simplify the obligation clause resolution [#103902](https://github.com/rust-lang/rust/pull/103902) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=95b61d16d4bd2e46b0a110c1bda703f026f0a94f&end=027c8507b4265dcf285b0b503e2a49214b929f7b&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.3% | [-0.3%, -0.2%] | 4     |
+| Improvements ✅ <br /> (secondary) | -0.4% | [-0.5%, -0.3%] | 3     |
+| All ❌✅ (primary)                 | -0.3% | [-0.3%, -0.2%] | 4     |
+
+
+InstCombine away intrinsic validity assertions [#105582](https://github.com/rust-lang/rust/pull/105582) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=2a17174ee639f8e0a3cee307d5685d38beb474ba&end=885bf628879310b885721e1fdd91ea2cbca9311f&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.2% | [-0.3%, -0.2%] | 6     |
+| Improvements ✅ <br /> (secondary) | -0.6% | [-1.3%, -0.3%] | 4     |
+| All ❌✅ (primary)                 | -0.2% | [-0.3%, -0.2%] | 6     |
+
+
+Only compute mir_generator_witnesses query in drop_tracking_mir mode. [#107406](https://github.com/rust-lang/rust/pull/107406) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=9f82651a5fa4b1d96f55ce5507dd2aa204c7fb61&end=bcb064a7f4aee705c97ce1b74beb9af0f9b5adb2&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -3.7% | [-5.7%, -1.1%] | 10    |
+| All ❌✅ (primary)                 | -     | -              | 0     |
+
+
+Test drop_tracking_mir before querying generator. [#107443](https://github.com/rust-lang/rust/pull/107443) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=487e83b711b96d84ce2edfc4cb4ba792c10b589e&end=dc3e59cb3fe05ebd752d3a2269f501c00327be22&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.5% | [-0.6%, -0.2%] | 14    |
+| Improvements ✅ <br /> (secondary) | -0.7% | [-1.0%, -0.4%] | 8     |
+| All ❌✅ (primary)                 | -0.5% | [-0.6%, -0.2%] | 14    |
+
+
+#### Mixed
+
+Move format_args!() into AST (and expand it during AST lowering) [#106745](https://github.com/rust-lang/rust/pull/106745) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=40fda7b3fe2b10c6e1a0568b59516f5e7f381886&end=3e977638728922d3a6cc7bea34a2fdb8ae97f7c0&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.6%  | [0.2%, 0.8%]   | 4     |
+| Regressions ❌ <br /> (secondary)  | 0.8%  | [0.3%, 1.3%]   | 3     |
+| Improvements ✅ <br /> (primary)   | -0.6% | [-2.3%, -0.2%] | 51    |
+| Improvements ✅ <br /> (secondary) | -0.7% | [-0.8%, -0.7%] | 6     |
+| All ❌✅ (primary)                 | -0.6% | [-2.3%, 0.8%]  | 55    |
+
+Overall mostly an improvement, not worth further investigation.
+
+Rollup of 8 pull requests [#107343](https://github.com/rust-lang/rust/pull/107343) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=db137ba7d4415ac77e2b7601ef017ff2ca41b335&end=18890f05f6cea40fd25bb4bb9aa6f7372b69f641&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.7%  | [0.5%, 0.8%]   | 7     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -0.4% | [-0.4%, -0.4%] | 1     |
+| All ❌✅ (primary)                 | 0.7%  | [0.5%, 0.8%]   | 7     |
+
+Regressions are limited to a single primary benchmark (bitmaps), and don't seem
+large enough to warrant spending further time investigating.
+
+rustdoc: Collect "rustdoc-reachable" items during early doc link resolution [#107054](https://github.com/rust-lang/rust/pull/107054) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=18890f05f6cea40fd25bb4bb9aa6f7372b69f641&end=6874f4e3fc2a16be7c78e702d068bbc1daa90e16&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.4%  | [0.3%, 0.4%]   | 2     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.5% | [-1.0%, -0.3%] | 4     |
+| Improvements ✅ <br /> (secondary) | -0.6% | [-0.9%, -0.2%] | 14    |
+| All ❌✅ (primary)                 | -0.2% | [-1.0%, 0.4%]  | 6     |
+
+Wins generally outweigh small regressions.
+
+Compute generator saved locals on MIR [#101692](https://github.com/rust-lang/rust/pull/101692) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=7d4df2d30eb342af1ef136d83d70d281f34adcd7&end=6cd6bad51fb34a0d89e97c27814041fe4d0838b5&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.6%  | [0.4%, 0.6%]   | 14    |
+| Regressions ❌ <br /> (secondary)  | 2.2%  | [0.3%, 6.0%]   | 22    |
+| Improvements ✅ <br /> (primary)   | -0.4% | [-0.7%, -0.2%] | 12    |
+| Improvements ✅ <br /> (secondary) | -     | -              | 0     |
+| All ❌✅ (primary)                 | 0.1%  | [-0.7%, 0.6%]  | 26    |
+
+Follow-up in #107406 has resolved 5% regression here, leaving ~1% regressions,
+but those are likely overall OK.
+
+Rollup of 9 pull requests [#107408](https://github.com/rust-lang/rust/pull/107408) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=d8da51366817317d19be9bd138943eafb30bc987&end=bca8b4dc32ec20f9a4e0ca55f54e5b2a531936fc&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 1.8%  | [1.5%, 2.1%]   | 6     |
+| Regressions ❌ <br /> (secondary)  | 0.6%  | [0.2%, 1.8%]   | 5     |
+| Improvements ✅ <br /> (primary)   | -0.6% | [-0.6%, -0.6%] | 2     |
+| Improvements ✅ <br /> (secondary) | -     | -              | 0     |
+| All ❌✅ (primary)                 | 1.2%  | [-0.6%, 2.1%]  | 8     |
+
+
+Remove HirId -> LocalDefId map from HIR. [#107206](https://github.com/rust-lang/rust/pull/107206) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=bca8b4dc32ec20f9a4e0ca55f54e5b2a531936fc&end=d6f0642827e21a088b0130c84857d84f5433301d&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | 0.3%  | [0.2%, 0.4%]   | 5     |
+| Improvements ✅ <br /> (primary)   | -0.3% | [-0.4%, -0.2%] | 7     |
+| Improvements ✅ <br /> (secondary) | -0.3% | [-0.4%, -0.3%] | 7     |
+| All ❌✅ (primary)                 | -0.3% | [-0.4%, -0.2%] | 7     |