Finish triage for 2025-07-07

Author: panstromek

triage/2025/2025-07-07.md

@@ -1,20 +1,21 @@
 # 2025-07-07 Triage Log
 
-TODO: Summary
-x
+Busy week. Results are dominated by changes that trade some wins for some losses in small incremental scenarios. We also had a lot of noise and spurious small changes on various PRs. Some regressions come from perf related work where we expect to get some wins back later.
+
 Triage done by **@panstromek**.
 Revision range: [ad3b7257..0d11be5a](https://perf.rust-lang.org/?start=ad3b7257615c28aaf8212a189ec032b8af75de51&end=0d11be5aabe0cd49609fff5fce57c4691a22fe55&absolute=false&stat=instructions%3Au)
 
 **Summary**:
 
+Note: We switched to a new benchmark machine at the begining of the period. We show summary based on slightly adjusted range [6988a8fe..8df4a58a](https://perf.rust-lang.org/?start=6988a8fea774a2a20ebebddb7dbf15dd6ef594f9&end=8df4a58ac47b778b093652d6190a6f9d54638774&absolute=false&stat=instructions%3Au) to avoid misleading comparisons from different machines.
+
 | (instructions:u)                   | mean  | range           | count |
 |:----------------------------------:|:-----:|:---------------:|:-----:|
-| Regressions ❌ <br /> (primary)    | 1.0%  | [0.2%, 2.8%]    | 44    |
-| Regressions ❌ <br /> (secondary)  | 0.9%  | [0.4%, 2.7%]    | 14    |
-| Improvements ✅ <br /> (primary)   | -2.2% | [-7.9%, -0.2%]  | 213   |
-| Improvements ✅ <br /> (secondary) | -3.1% | [-44.7%, -0.2%] | 255   |
-| All ❌✅ (primary)                 | -1.6% | [-7.9%, 2.8%]   | 257   |
-
+| Regressions ❌ <br /> (primary)    | 1.1%  | [0.2%, 4.3%]    | 128   |
+| Regressions ❌ <br /> (secondary)  | 1.0%  | [0.2%, 3.9%]    | 84    |
+| Improvements ✅ <br /> (primary)   | -3.5% | [-7.2%, -0.2%]  | 48    |
+| Improvements ✅ <br /> (secondary) | -5.1% | [-42.6%, -0.2%] | 68    |
+| All ❌✅ (primary)                 | -0.2% | [-7.2%, 4.3%]   | 176   |
 
 3 Regressions, 3 Improvements, 11 Mixed; 6 of them in rollups
 44 artifact comparisons made in total
@@ -31,7 +32,7 @@ Rollup of 8 pull requests [#143267](https://github.com/rust-lang/rust/pull/14326
 | Improvements ✅ <br /> (secondary) | -    | -            | 0     |
 | All ❌✅ (primary)                 | 0.2% | [0.2%, 0.2%] | 1     |
 
-Second commit benchmarked on new machine. The regressed benchmarks are small and fairly aritifical. Some of the results look like noise and returned to previous state. I don't think this is worth investigating more.
+The regressed benchmarks are small and fairly aritifical. Some of the results look like noise and returned to previous state. I don't think this is worth investigating more.
 
 Add new self-profiling event to cheaply aggregate query cache hit counts [#142978](https://github.com/rust-lang/rust/pull/142978) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=f51c9870bab634afb9e7a262b6ca7816bb9e940d&end=b94bd12401d26ccf1c3b04ceb4e950b0ff7c8d29&stat=instructions:u)
 
@@ -55,7 +56,7 @@ Do not unify borrowed locals in CopyProp. [#143509](https://github.com/rust-lang
 | Improvements ✅ <br /> (secondary) | -     | -              | 0     |
 | All ❌✅ (primary)                 | 0.1%  | [-0.4%, 0.3%]  | 23    |
 
-Soundness fix. Posted a comment to make sure these are expected.
+Soundness fix in an mir-opt pass. Posted a comment to make sure these are expected.
 
 #### Improvements
 
@@ -104,7 +105,7 @@ Introduce `ByteSymbol` [#141875](https://github.com/rust-lang/rust/pull/141875)
 | Improvements ✅ <br /> (secondary) | -1.9% | [-6.1%, -0.3%] | 298   |
 | All ❌✅ (primary)                 | -1.5% | [-6.4%, -0.2%] | 264   |
 
-First PR benchmarked on new machine, these results are not "real"
+First PR benchmarked on new machine, these changes are not real as they compare results from different machines. Pre-merge results are much less significant.
 
 Start moving wf checking away from HIR [#142030](https://github.com/rust-lang/rust/pull/142030) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=076a0a26fd6f4c445647a33d6daaac56f732ac05&end=4e973370053a5fe87ee96d43c506623e9bd1eb9d&stat=instructions:u)
 
@@ -128,7 +129,7 @@ Rollup of 11 pull requests [#143338](https://github.com/rust-lang/rust/pull/1433
 | Improvements ✅ <br /> (secondary) | -0.1% | [-0.1%, -0.1%] | 1     |
 | All ❌✅ (primary)                 | 0.4%  | [0.3%, 0.4%]   | 2     |
 
-Most of the regressions are probably safe to ignore (small, secondary or noise). The biggest one is in cargo, where the regression is in LLVM, which indicates something probably changed in relation to optmizations or codegen scheduling. Most of the changes here seem unrelated, though. I suspect it could be one of the standard library changes in first three PRs.
+Most of the regressions are probably safe to ignore (small, secondary or noise). The biggest one is in cargo, where the regression is in LLVM, which indicates something probably changed in relation to optmizations or codegen scheduling. Most of the code changes here seem unrelated, though. I suspect it could be one of the standard library changes in first three PRs.
 
 This seems to have returned back to previous state with a little improvement on top in https://github.com/rust-lang/rust/pull/143509, detailed results show inverse numbers on the same LLVM-related queries, but since that PR changed mir optimizations, it probably has some effect on that, too.
 
@@ -190,7 +191,7 @@ Make metadata a workproduct and reuse it [#114669](https://github.com/rust-lang/
 | Improvements ✅ <br /> (secondary) | -4.9% | [-11.6%, -0.5%] | 36    |
 | All ❌✅ (primary)                 | -1.0% | [-7.5%, 2.2%]   | 121   |
 
-Regressions outweigh improvements. Note that lot of the regressions are on very small benchmarks, so the negative effects are somewhat exagerrated. Based on PR description, this change also targets worspace use case that is not represented well in our benchmarks.
+Regressions outweigh improvements. Note that lot of the regressions are on very small benchmarks, so the negative effects are somewhat exaggerated. Based on PR description, this change also targets worspace use case that is not represented well in our benchmarks.
 
 Remove `Symbol` from `Named` variant of `BoundRegionKind`/`LateParamRegionKind` [#139598](https://github.com/rust-lang/rust/pull/139598) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=733b47ea4b1b86216f14ef56e49440c33933f230&end=f0b67dd97d74610ee4185cf01c775a563c2017a2&stat=instructions:u)