Filled in weekly triage report.

Author: pnkfelix

triage/2024-06-03.md

@@ -1,8 +1,12 @@
 # 2024-06-03 Triage Log
 
-TODO: Summary
+A quiet week; we did have one quite serious regression (#115105, "enable
+DestinationPropagation by default"), but it was shortly reverted (#125794).
+The only other PR identified as potentially problematic was rollup
+[PR #125824](https://github.com/rust-lang/rust/pull/125824), but even
+that is relatively limited in its effect.
 
-Triage done by **@???**.
+Triage done by **@pnkfelix**.
 Revision range: [a59072ec..1d52972d](https://perf.rust-lang.org/?start=a59072ec4fb6824213df5e9de8cae4812fd4fe97&end=1d52972dd8592edf4026aa577c8ce69acc0ac2d1&absolute=false&stat=instructions%3Au)
 
 **Summary**:
@@ -31,6 +35,11 @@ Rollup of 5 pull requests [#125649](https://github.com/rust-lang/rust/pull/12564
 | Improvements ✅ <br /> (secondary) | -     | -              | 0     |
 | All ❌✅ (primary)                 | 1.2%  | [-0.1%, 2.1%]  | 13    |
 
+* all 12 of the regressing primary benchmarks are diesel-1.4.8 (in a variety of configurations).
+* problem was isolated to PR #125089 (improve diagnostic output of non_local_definitions lint)
+* Urgau notes: "The lint triggers nearly 150 times in the version of diesel used by rustc-perf, so the benchmark has become a bit a linting machinery benchmark"
+* cc rustc-perf#1819
+* marked as triaged.
 
 Rollup of 5 pull requests [#125665](https://github.com/rust-lang/rust/pull/125665) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=8c4db851a7bb64173832e6602638204ebbd373a8&end=274499dd0ff53b81e93b80520f7afe25adaa2812&stat=instructions:u)
 
@@ -42,6 +51,9 @@ Rollup of 5 pull requests [#125665](https://github.com/rust-lang/rust/pull/12566
 | Improvements ✅ <br /> (secondary) | -    | -            | 0     |
 | All ❌✅ (primary)                 | 0.5% | [0.5%, 0.5%] | 1     |
 
+* helloworld is sole primary regression.
+* marked as triaged (my own opinion is that helloworld is a useful canary when it regresses by a more significant amount than this)
+* (also the 30-day history shows the story for helloworld to be quite a bit more complicated than what is presented by the effects of this single PR, there are lots of spikes mixed in there)
 
 fn_arg_sanity_check: fix panic message [#125695](https://github.com/rust-lang/rust/pull/125695) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=5870f1ccbbb2661c92cdc356231386210a64d723&end=4cf5723dbe471ef0a32857b968b91498551f5e38&stat=instructions:u)
 
@@ -53,6 +65,8 @@ fn_arg_sanity_check: fix panic message [#125695](https://github.com/rust-lang/ru
 | Improvements ✅ <br /> (secondary) | -    | -            | 0     |
 | All ❌✅ (primary)                 | 0.8% | [0.8%, 0.9%] | 4     |
 
+* helloworld is the sole primary regression.
+* (already) marked as triaged
 
 #### Improvements
 
@@ -66,6 +80,8 @@ Omit non-needs_drop drop_in_place in vtables [#122662](https://github.com/rust-l
 | Improvements ✅ <br /> (secondary) | -0.5% | [-1.0%, -0.2%] | 18    |
 | All ❌✅ (primary)                 | -0.6% | [-1.5%, -0.2%] | 9     |
 
+* improvements are to helloworld-opt and regex-opt.
+* small but seems real given nature of PR (largely a binary size reduction)
 
 Update cargo [#125682](https://github.com/rust-lang/rust/pull/125682) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=274499dd0ff53b81e93b80520f7afe25adaa2812&end=da159eb331b27df528185c616b394bb0e1d2a4bd&stat=instructions:u)
 
@@ -77,6 +93,8 @@ Update cargo [#125682](https://github.com/rust-lang/rust/pull/125682) [(Comparis
 | Improvements ✅ <br /> (secondary) | -0.4% | [-0.5%, -0.2%] | 12    |
 | All ❌✅ (primary)                 | -0.5% | [-0.6%, -0.5%] | 3     |
 
+* improvements are to helloworld-check
+* probably just noise
 
 Stabilize `custom_code_classes_in_docs` feature [#124577](https://github.com/rust-lang/rust/pull/124577) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=466be510af95d377a4e9997a6ab7c4db5f91e9ec&end=05965ae238403d8c141170b411245a62aa046240&stat=instructions:u)
 
@@ -88,6 +106,8 @@ Stabilize `custom_code_classes_in_docs` feature [#124577](https://github.com/rus
 | Improvements ✅ <br /> (secondary) | -0.7% | [-0.9%, -0.5%] | 2     |
 | All ❌✅ (primary)                 | -0.4% | [-0.8%, -0.2%] | 9     |
 
+* improvements are to various doc-full benchmarks.
+* Probably measurement bias (unless somehow the stability checks are a noticeable expense?)
 
 Increase vtable layout size [#123572](https://github.com/rust-lang/rust/pull/123572) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=acaf0aeed0dfbfc4be9f996344e2c5f294cf5794&end=f2208b32971faba7fa6bf09bd0821adbf3db0c00&stat=instructions:u)
 
@@ -99,6 +119,8 @@ Increase vtable layout size [#123572](https://github.com/rust-lang/rust/pull/123
 | Improvements ✅ <br /> (secondary) | -0.3% | [-0.6%, -0.2%] | 10    |
 | All ❌✅ (primary)                 | -     | -              | 0     |
 
+* all "improvements" are to secondary benchmarks: unify-linearly, match-stress, and unused-warnings
+* (the improvement from this PR is expected to be realized in runtime performance, especially for code heavy with vtable lookups. Its unsurprising that it wouldn't have a noticeable effect on the compiler tooolchain.)
 
 Avoid checking the edition as much as possible [#125828](https://github.com/rust-lang/rust/pull/125828) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=eda9d7f987de76b9d61c633a6ac328936e1b94f0&end=a6416d8907bc94ef1a032d54cb0443cde963e455&stat=instructions:u)
 
@@ -110,6 +132,7 @@ Avoid checking the edition as much as possible [#125828](https://github.com/rust
 | Improvements ✅ <br /> (secondary) | -0.4% | [-0.5%, -0.3%] | 4     |
 | All ❌✅ (primary)                 | -0.4% | [-0.4%, -0.3%] | 6     |
 
+* this is recovering performance that was lost in PR #123865
 
 #### Mixed
 
@@ -123,6 +146,8 @@ Create const block DefIds in typeck instead of ast lowering [#124650](https://gi
 | Improvements ✅ <br /> (secondary) | -0.3% | [-0.3%, -0.3%] | 1     |
 | All ❌✅ (primary)                 | -0.3% | [-0.6%, 0.2%]  | 8     |
 
+* as previously noted by @lqd : "Tiny changes, and overall more gains than losses, probably not worth investigation effort imho."
+* marking as triaged
 
 Rollup of 8 pull requests [#125691](https://github.com/rust-lang/rust/pull/125691) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=da159eb331b27df528185c616b394bb0e1d2a4bd&end=751691271d76b8435559200b84d1947c2bd735bd&stat=instructions:u)
 
@@ -134,6 +159,10 @@ Rollup of 8 pull requests [#125691](https://github.com/rust-lang/rust/pull/12569
 | Improvements ✅ <br /> (secondary) | -0.3% | [-0.3%, -0.3%] | 1     |
 | All ❌✅ (primary)                 | -0.2% | [-0.6%, 0.4%]  | 3     |
 
+* regression to image-opt-full
+* improvements to webrender-2022-opt-full and regex-opt-incr-patched
+* had a broad (if small) improvement to binary sizes, which was isolated to PR #124251
+* overall wins seem to outweigh losses; marking as triaged.
 
 don't inhibit random field reordering on repr(packed(1)) [#125360](https://github.com/rust-lang/rust/pull/125360) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=4cf5723dbe471ef0a32857b968b91498551f5e38&end=f2e1a3a80ae54734e1a3d306f31c2caebb05de9b&stat=instructions:u)
 
@@ -145,6 +174,9 @@ don't inhibit random field reordering on repr(packed(1)) [#125360](https://githu
 | Improvements ✅ <br /> (secondary) | -0.4% | [-0.7%, -0.3%] | 13    |
 | All ❌✅ (primary)                 | 0.5%  | [-0.8%, 1.3%]  | 17    |
 
+* regressed bitmaps and typenum; improved helloworld
+* instruction counts were affected but not cycle counts; [one theory is that object code has extra offset computations or niche computations...](https://github.com/rust-lang/rust/pull/125360#issuecomment-2137781620)
+* since cycle count was not affected, does not seem worth further investigation; marking as triaged
 
 Enable DestinationPropagation by default. [#115105](https://github.com/rust-lang/rust/pull/115105) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=91c0823ee63e793d990bb9fed898dc95b5d6db51&end=cfb730450f847bb622243eaaab15e77e58d91767&stat=instructions:u)
 
@@ -156,6 +188,8 @@ Enable DestinationPropagation by default. [#115105](https://github.com/rust-lang
 | Improvements ✅ <br /> (secondary) | -0.8% | [-1.6%, -0.2%] | 18    |
 | All ❌✅ (primary)                 | 0.2%  | [-4.0%, 3.4%]  | 41    |
 
+* was reverted due to injecting [big regression for "Building stage1 codegen backend gcc"](https://github.com/rust-lang/rust/pull/115105#issuecomment-2141019310)
+* marking as triaged
 
 Revert "Auto merge of #115105 - cjgillot:dest-prop-default, r=oli-obk" [#125794](https://github.com/rust-lang/rust/pull/125794) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=434999efe6e9aa61afbd8b4ae86864d3ce91c533&end=366da30d554719e7490950aeea5d3f3a5927e313&stat=instructions:u)
 
@@ -167,6 +201,8 @@ Revert "Auto merge of #115105 - cjgillot:dest-prop-default, r=oli-obk" [#125794]
 | Improvements ✅ <br /> (secondary) | -1.5% | [-3.1%, -0.4%] | 18    |
 | All ❌✅ (primary)                 | -0.2% | [-3.2%, 4.2%]  | 33    |
 
+* revert of above PR
+* marking as triaged
 
 Rollup of 7 pull requests [#125824](https://github.com/rust-lang/rust/pull/125824) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=2a2c29aafa50bf6fe53d66b32070eba59f860ac3&end=ada5e2c7b5427a591e30baeeee2698a5eb6db0bd&stat=instructions:u)
 
@@ -178,41 +214,8 @@ Rollup of 7 pull requests [#125824](https://github.com/rust-lang/rust/pull/12582
 | Improvements ✅ <br /> (secondary) | -     | -              | 0     |
 | All ❌✅ (primary)                 | 0.4%  | [-0.4%, 1.1%]  | 4     |
 
-
-#### Untriaged Pull Requests
-
-- [#125824 Rollup of 7 pull requests](https://github.com/rust-lang/rust/pull/125824)
-- [#125794 Revert "Auto merge of #115105 - cjgillot:dest-prop-default, r=oli-obk"](https://github.com/rust-lang/rust/pull/125794)
-- [#125691 Rollup of 8 pull requests](https://github.com/rust-lang/rust/pull/125691)
-- [#125665 Rollup of 5 pull requests](https://github.com/rust-lang/rust/pull/125665)
-- [#125649 Rollup of 5 pull requests](https://github.com/rust-lang/rust/pull/125649)
-- [#125360 don't inhibit random field reordering on repr(packed(1))](https://github.com/rust-lang/rust/pull/125360)
-- [#125144 Rollup of 6 pull requests](https://github.com/rust-lang/rust/pull/125144)
-- [#125120 Rollup of 7 pull requests](https://github.com/rust-lang/rust/pull/125120)
-- [#124700 Remove an unnecessary cast](https://github.com/rust-lang/rust/pull/124700)
-- [#124650 Create const block DefIds in typeck instead of ast lowering](https://github.com/rust-lang/rust/pull/124650)
-- [#124417 Make early lints translatable](https://github.com/rust-lang/rust/pull/124417)
-- [#124241 Rollup of 5 pull requests](https://github.com/rust-lang/rust/pull/124241)
-- [#123909 Stabilize `Utf8Chunks`](https://github.com/rust-lang/rust/pull/123909)
-- [#123865 Update `expr` matcher for Edition 2024 and add `expr_2021` nonterminal](https://github.com/rust-lang/rust/pull/123865)
-- [#123812 Follow-up fixes to `report_return_mismatched_types`](https://github.com/rust-lang/rust/pull/123812)
-- [#123147 Rollup of 8 pull requests](https://github.com/rust-lang/rust/pull/123147)
-- [#122976 Remove len argument from RawVec::reserve_for_push](https://github.com/rust-lang/rust/pull/122976)
-- [#122900 Rollup of 8 pull requests](https://github.com/rust-lang/rust/pull/122900)
-- [#122671 Codegen const panic messages as function calls](https://github.com/rust-lang/rust/pull/122671)
-- [#122396 Less generic code for Vec allocations](https://github.com/rust-lang/rust/pull/122396)
-- [#121955 Rollup of 5 pull requests](https://github.com/rust-lang/rust/pull/121955)
-- [#121804 Rollup of 7 pull requests](https://github.com/rust-lang/rust/pull/121804)
-- [#121752 Detect unused struct impls pub trait](https://github.com/rust-lang/rust/pull/121752)
-- [#121462 Combine `Sub` and `Equate`](https://github.com/rust-lang/rust/pull/121462)
-- [#121345 Rollup of 8 pull requests](https://github.com/rust-lang/rust/pull/121345)
-- [#120985 Update host LLVM on x64 Linux to LLVM 18](https://github.com/rust-lang/rust/pull/120985)
-- [#120863 Use intrinsics::debug_assertions in debug_assert_nounwind](https://github.com/rust-lang/rust/pull/120863)
-- [#120862 Rollup of 6 pull requests](https://github.com/rust-lang/rust/pull/120862)
-- [#120809 Use `transmute_unchecked` in `NonZero::new`.](https://github.com/rust-lang/rust/pull/120809)
-- [#120588 wasm: Store rlib metadata in wasm object files](https://github.com/rust-lang/rust/pull/120588)
-
-#### Nags requiring follow up
-
-TODO: Nags
-
+* instruction-counts regressed webrender-2022-opt-full, cargo-opt-{incr-patched, full}
+* cycle-counts regressed webrender-2022-opt-{full, incr-full}, cranelift-codegen-opt-incr-full, and clap-opt-incr-patched
+* history view for webrender shows that the cycle-count effect seems real though not quite as pronounced as the original measurements indicate.
+* there are many potential candidates for the cause here in this rollup.
+* not marking as triaged; doing some followup perf runs on individual PR's