|
| 1 | +# 2022-08-24 Triage Log |
| 2 | + |
| 3 | +Overall some really impressive wins this week. Note in particular |
| 4 | +PR [#100209](https://github.com/rust-lang/rust/pull/100209), "Lazily |
| 5 | +decode SourceFile from metadata" (which improved 75 primary benchmark |
| 6 | +scenarios and 158 secondary scenarios) and |
| 7 | +PR [#98655](https://github.com/rust-lang/rust/pull/98655) "Don't derive |
| 8 | +`PartialEq::ne`", which improved 65 primary scenarios and 27 secondary |
| 9 | +scenarios). There were a few cases that pnkfelix explicitly decided not |
| 10 | +to mark as triaged; see report for more details there. |
| 11 | +Also pnkfelix wonders if there is a recent slight-upward trend on max-rss |
| 12 | +for the past week, see the [summary graph](https://perf.rust-lang.org/?start=&end=&kind=percentfromfirst&stat=max-rss) |
| 13 | + |
| 14 | +Triage done by **@pnkfelix**. |
| 15 | +Revision range: [14a459bf..4a24f08b](https://perf.rust-lang.org/?start=14a459bf37bc19476d43e0045d078121c12d3fef&end=4a24f08ba43166cfee86d868b3fe8612aec6faca&absolute=false&stat=instructions%3Au) |
| 16 | + |
| 17 | +**Summary**: |
| 18 | + |
| 19 | +| (instructions:u) | mean | range | count | |
| 20 | +|:----------------:|:----:|:-----:|:-----:| |
| 21 | +| Regressions ❌ <br /> (primary) | 0.6% | [0.4%, 0.8%] | 27 | |
| 22 | +| Regressions ❌ <br /> (secondary) | 0.4% | [0.2%, 0.6%] | 9 | |
| 23 | +| Improvements ✅ <br /> (primary) | -1.7% | [-20.1%, -0.3%] | 91 | |
| 24 | +| Improvements ✅ <br /> (secondary) | -3.6% | [-18.7%, -0.3%] | 160 | |
| 25 | +| All ❌✅ (primary) | -1.2% | [-20.1%, 0.8%] | 118 | |
| 26 | + |
| 27 | + |
| 28 | +3 Regressions, 4 Improvements, 4 Mixed; 3 of them in rollups |
| 29 | +43 artifact comparisons made in total |
| 30 | + |
| 31 | +#### Regressions |
| 32 | + |
| 33 | +Rollup of 15 pull requests [#100677](https://github.com/rust-lang/rust/pull/100677) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=86c6ebee8fa0a5ad1e18e375113b06bd2849b634&end=9c20b2a8cc7588decb6de25ac6a7912dcef24d65&stat=instructions:u) |
| 34 | + |
| 35 | +| (instructions:u) | mean | range | count | |
| 36 | +|:----------------:|:----:|:-----:|:-----:| |
| 37 | +| Regressions ❌ <br /> (primary) | 0.3% | [0.3%, 0.3%] | 2 | |
| 38 | +| Regressions ❌ <br /> (secondary) | 1.3% | [0.5%, 1.9%] | 4 | |
| 39 | +| Improvements ✅ <br /> (primary) | - | - | 0 | |
| 40 | +| Improvements ✅ <br /> (secondary) | - | - | 0 | |
| 41 | +| All ❌✅ (primary) | 0.3% | [0.3%, 0.3%] | 2 | |
| 42 | + |
| 43 | +* lqd hypothesized this was caused by PR #100652 "Remove deferred sized checks (make them eager)" |
| 44 | +* regressions for #100652 include most of the rollup regressions, all by similar amounts (only ucd was absent from the narrower view). |
| 45 | +* left a [comment](https://github.com/rust-lang/rust/pull/100652#issuecomment-1225798572) on PR #100652 and marked it as a regression; marked rollup as triaged. |
| 46 | + |
| 47 | +rustc_metadata: dedupe strings to prevent multiple copies in rmeta/query cache blow file size [#98851](https://github.com/rust-lang/rust/pull/98851) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=0b79f758c9aa6646606662a6d623a0752286cd17&end=71ecf5d359bf750cc171e124779a46985633439d&stat=instructions:u) |
| 48 | + |
| 49 | +| (instructions:u) | mean | range | count | |
| 50 | +|:----------------:|:----:|:-----:|:-----:| |
| 51 | +| Regressions ❌ <br /> (primary) | 0.6% | [0.3%, 1.5%] | 15 | |
| 52 | +| Regressions ❌ <br /> (secondary) | 1.1% | [0.3%, 1.6%] | 21 | |
| 53 | +| Improvements ✅ <br /> (primary) | - | - | 0 | |
| 54 | +| Improvements ✅ <br /> (secondary) | -0.4% | [-0.6%, -0.2%] | 2 | |
| 55 | +| All ❌✅ (primary) | 0.6% | [0.3%, 1.5%] | 15 | |
| 56 | + |
| 57 | +* the performance of this PR was heavily evaluated as part of its development. |
| 58 | +* some regression to instruction counts is compensated for by the improvements file-size and to max-rss. |
| 59 | +* the follow-up PR [#100803](https://github.com/rust-lang/rust/issues/100803) is going to more than compensate for the regressions here. |
| 60 | +* marked as triaged. |
| 61 | + |
| 62 | + |
| 63 | +implied bounds: explicitly state which types are assumed to be wf [#100676](https://github.com/rust-lang/rust/pull/100676) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=d0ea1d767925d53b2230e2ba81197821514781f0&end=a9bb589cd678e034d194193fa892942315b10e2a&stat=instructions:u) |
| 64 | + |
| 65 | +| (instructions:u) | mean | range | count | |
| 66 | +|:----------------:|:----:|:-----:|:-----:| |
| 67 | +| Regressions ❌ <br /> (primary) | 0.3% | [0.2%, 0.5%] | 22 | |
| 68 | +| Regressions ❌ <br /> (secondary) | 0.4% | [0.2%, 0.8%] | 22 | |
| 69 | +| Improvements ✅ <br /> (primary) | - | - | 0 | |
| 70 | +| Improvements ✅ <br /> (secondary) | - | - | 0 | |
| 71 | +| All ❌✅ (primary) | 0.3% | [0.2%, 0.5%] | 22 | |
| 72 | + |
| 73 | +* This PR was intended to be a refactor, but it turns out it has other problems (see [issue 100910](https://github.com/rust-lang/rust/issues/100910)). |
| 74 | +* The regressions alone are not cause to revert the PR, but the soundness bug pushes me over the line. |
| 75 | +* Nominated for discussion (of revert) in Thursday's T-compiler meeting. Not tagging as triaged. |
| 76 | + |
| 77 | +#### Improvements |
| 78 | + |
| 79 | +Don't derive `PartialEq::ne`. [#98655](https://github.com/rust-lang/rust/pull/98655) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=f241c0c43d71960f078b897e9b8721d4b452ce5e&end=361c599feeefaf6e50efd90658fc9c2222154684&stat=instructions:u) |
| 80 | + |
| 81 | +| (instructions:u) | mean | range | count | |
| 82 | +|:----------------:|:----:|:-----:|:-----:| |
| 83 | +| Regressions ❌ <br /> (primary) | - | - | 0 | |
| 84 | +| Regressions ❌ <br /> (secondary) | 1.0% | [1.0%, 1.0%] | 1 | |
| 85 | +| Improvements ✅ <br /> (primary) | -0.7% | [-1.4%, -0.2%] | 65 | |
| 86 | +| Improvements ✅ <br /> (secondary) | -5.2% | [-10.0%, -0.3%] | 27 | |
| 87 | +| All ❌✅ (primary) | -0.7% | [-1.4%, -0.2%] | 65 | |
| 88 | + |
| 89 | +* This had an interesting discussion thread on it; see [nnethercote's summary comment](https://github.com/rust-lang/rust/pull/98655#issuecomment-1176827089) for more info. |
| 90 | + |
| 91 | +Lazily decode SourceFile from metadata [#100209](https://github.com/rust-lang/rust/pull/100209) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=6c943bad02626dddc5e5135b23c77429b6e4a063&end=468887ef91e46847dff57b6b234cff0fad17cb71&stat=instructions:u) |
| 92 | + |
| 93 | +| (instructions:u) | mean | range | count | |
| 94 | +|:----------------:|:----:|:-----:|:-----:| |
| 95 | +| Regressions ❌ <br /> (primary) | 0.2% | [0.2%, 0.2%] | 2 | |
| 96 | +| Regressions ❌ <br /> (secondary) | 0.7% | [0.4%, 0.9%] | 3 | |
| 97 | +| Improvements ✅ <br /> (primary) | -1.6% | [-19.6%, -0.2%] | 75 | |
| 98 | +| Improvements ✅ <br /> (secondary) | -3.0% | [-18.3%, -0.2%] | 158 | |
| 99 | +| All ❌✅ (primary) | -1.6% | [-19.6%, 0.2%] | 77 | |
| 100 | + |
| 101 | +* Don't get too excited y'all, that 19.6% improvement was to helloworld. |
| 102 | +* having said that, this does represent a huge win across a broad suite of benchmarks, nearly all in incremental. |
| 103 | +* (also, lqd notes that helloworld is a useful proxy for near-trivial build.rs scripts.) |
| 104 | + |
| 105 | +Update minifier version to 0.2.2 [#100624](https://github.com/rust-lang/rust/pull/100624) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=f2858b5cd32f3689ad83de77cacfa1ea2f533793&end=aa8e761defc245d08d2cf226786def8a8bb56e53&stat=instructions:u) |
| 106 | + |
| 107 | +| (instructions:u) | mean | range | count | |
| 108 | +|:----------------:|:----:|:-----:|:-----:| |
| 109 | +| Regressions ❌ <br /> (primary) | - | - | 0 | |
| 110 | +| Regressions ❌ <br /> (secondary) | - | - | 0 | |
| 111 | +| Improvements ✅ <br /> (primary) | -0.6% | [-1.6%, -0.3%] | 13 | |
| 112 | +| Improvements ✅ <br /> (secondary) | -1.1% | [-1.5%, -0.3%] | 20 | |
| 113 | +| All ❌✅ (primary) | -0.6% | [-1.6%, -0.3%] | 13 | |
| 114 | + |
| 115 | +* As noted by nnethercote, the cycles and max-rss results are neutral or under noise threshold, while instruction counts improved. |
| 116 | + |
| 117 | +Kind-less SessionDiagnostic derive [#100765](https://github.com/rust-lang/rust/pull/100765) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=39a9b88f4e50d4c0204bb12c0821b49a302ab3c5&end=4b695f7c4e1a02d160fe7e159abd0f87027c0fcf&stat=instructions:u) |
| 118 | + |
| 119 | +| (instructions:u) | mean | range | count | |
| 120 | +|:----------------:|:----:|:-----:|:-----:| |
| 121 | +| Regressions ❌ <br /> (primary) | - | - | 0 | |
| 122 | +| Regressions ❌ <br /> (secondary) | - | - | 0 | |
| 123 | +| Improvements ✅ <br /> (primary) | -0.8% | [-0.9%, -0.6%] | 5 | |
| 124 | +| Improvements ✅ <br /> (secondary) | - | - | 0 | |
| 125 | +| All ❌✅ (primary) | -0.8% | [-0.9%, -0.6%] | 5 | |
| 126 | + |
| 127 | +* all five improvements are to instances of regex-opt-incr-{patched,full} benchmark |
| 128 | + |
| 129 | +#### Mixed |
| 130 | + |
| 131 | +Rollup of 9 pull requests [#100810](https://github.com/rust-lang/rust/pull/100810) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=48853a361a5ff0e8215301c62f259a26eed7aa72&end=878aef79dcdf59d19bb8482202dc55e58ceb62ff&stat=instructions:u) |
| 132 | + |
| 133 | +| (instructions:u) | mean | range | count | |
| 134 | +|:----------------:|:----:|:-----:|:-----:| |
| 135 | +| Regressions ❌ <br /> (primary) | - | - | 0 | |
| 136 | +| Regressions ❌ <br /> (secondary) | 0.3% | [0.2%, 0.3%] | 2 | |
| 137 | +| Improvements ✅ <br /> (primary) | -0.7% | [-0.9%, -0.3%] | 8 | |
| 138 | +| Improvements ✅ <br /> (secondary) | - | - | 0 | |
| 139 | +| All ❌✅ (primary) | -0.7% | [-0.9%, -0.3%] | 8 | |
| 140 | + |
| 141 | +* already triaged: "The small number of small improvements slightly outweighs the small number of small regressions. No further action is needed." |
| 142 | + |
| 143 | +update Miri [#100841](https://github.com/rust-lang/rust/pull/100841) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=4b695f7c4e1a02d160fe7e159abd0f87027c0fcf&end=31302033095dc75608675cd6f9b884d1692054f0&stat=instructions:u) |
| 144 | + |
| 145 | +| (instructions:u) | mean | range | count | |
| 146 | +|:----------------:|:----:|:-----:|:-----:| |
| 147 | +| Regressions ❌ <br /> (primary) | 0.8% | [0.5%, 1.0%] | 5 | |
| 148 | +| Regressions ❌ <br /> (secondary) | 0.2% | [0.2%, 0.2%] | 1 | |
| 149 | +| Improvements ✅ <br /> (primary) | -0.8% | [-0.8%, -0.8%] | 1 | |
| 150 | +| Improvements ✅ <br /> (secondary) | - | - | 0 | |
| 151 | +| All ❌✅ (primary) | 0.5% | [-0.8%, 1.0%] | 6 | |
| 152 | + |
| 153 | +* regressions were in regex-opt-incr-patched (and ucd-doc-full, but that was just 0.24%) |
| 154 | +* while the regression here is unfortunate, there is not much we can expect to do in the short term to address it |
| 155 | +* its not even clear whether miri is really at fault; the [detailed query](https://perf.rust-lang.org/detailed-query.html?commit=31302033095dc75608675cd6f9b884d1692054f0&base_commit=4b695f7c4e1a02d160fe7e159abd0f87027c0fcf&benchmark=regex-1.5.5-opt&scenario=incr-patched:%20reverse) info says that the regression is due to `LLVM_lto_optimize`. Could the miri changes have somehow caused the codegen unit partitioning to change? Why would a miri update affect the time for `LLVM_lto_optimize`? |
| 156 | +* not marking as triaged. I'm not sure if anyone can justify spending time to look at this, but I don't want to just let it slide through just yet. |
| 157 | + |
| 158 | +Rollup of 11 pull requests [#100847](https://github.com/rust-lang/rust/pull/100847) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=650bff80a623e17675ac72ae4d62ed200a4a3568&end=c0941dfb5a7d07ef2d70cc54d319669d9d6f6c01&stat=instructions:u) |
| 159 | + |
| 160 | +| (instructions:u) | mean | range | count | |
| 161 | +|:----------------:|:----:|:-----:|:-----:| |
| 162 | +| Regressions ❌ <br /> (primary) | - | - | 0 | |
| 163 | +| Regressions ❌ <br /> (secondary) | 0.2% | [0.2%, 0.2%] | 1 | |
| 164 | +| Improvements ✅ <br /> (primary) | -0.5% | [-0.5%, -0.5%] | 1 | |
| 165 | +| Improvements ✅ <br /> (secondary) | -0.7% | [-1.1%, -0.3%] | 5 | |
| 166 | +| All ❌✅ (primary) | -0.5% | [-0.5%, -0.5%] | 1 | |
| 167 | + |
| 168 | +* benefits here heavily outweigh the one minor regression. |
| 169 | +* already triaged by nnethercote |
| 170 | + |
| 171 | +Use `AttrVec` more [#100668](https://github.com/rust-lang/rust/pull/100668) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=0b71ffca18a9f4a9515773b2c23d13f501d1e08f&end=3ce46b74aa3968b459cff3ce5c0d4f13e220b217&stat=instructions:u) |
| 172 | + |
| 173 | +| (instructions:u) | mean | range | count | |
| 174 | +|:----------------:|:----:|:-----:|:-----:| |
| 175 | +| Regressions ❌ <br /> (primary) | 0.6% | [0.2%, 1.0%] | 2 | |
| 176 | +| Regressions ❌ <br /> (secondary) | 0.6% | [0.3%, 1.3%] | 8 | |
| 177 | +| Improvements ✅ <br /> (primary) | -0.3% | [-0.4%, -0.2%] | 7 | |
| 178 | +| Improvements ✅ <br /> (secondary) | -0.5% | [-1.2%, -0.2%] | 15 | |
| 179 | +| All ❌✅ (primary) | -0.1% | [-0.4%, 1.0%] | 9 | |
| 180 | + |
| 181 | +* already triaged by nnethercote: "a few small wins and losses here, which balance each other out, and the net effect is perf-neutral." |
| 182 | + |
| 183 | +#### Untriaged Pull Requests |
| 184 | + |
| 185 | +- [#100841 update Miri](https://github.com/rust-lang/rust/pull/100841) |
| 186 | +- [#100677 Rollup of 15 pull requests](https://github.com/rust-lang/rust/pull/100677) |
| 187 | +- [#100676 implied bounds: explicitly state which types are assumed to be wf](https://github.com/rust-lang/rust/pull/100676) |
| 188 | +- [#100429 rustdoc: Merge source code pages HTML elements together](https://github.com/rust-lang/rust/pull/100429) |
| 189 | +- [#99792 Rollup of 8 pull requests](https://github.com/rust-lang/rust/pull/99792) |
| 190 | +- [#99520 Rollup of 9 pull requests](https://github.com/rust-lang/rust/pull/99520) |
| 191 | +- [#99251 Upgrade indexmap and thorin-dwp to use hashbrown 0.12](https://github.com/rust-lang/rust/pull/99251) |
| 192 | +- [#99231 Rollup of 5 pull requests](https://github.com/rust-lang/rust/pull/99231) |
| 193 | +- [#99210 Rollup of 5 pull requests](https://github.com/rust-lang/rust/pull/99210) |
| 194 | +- [#99126 remove allow(rustc::potential_query_instability) in rustc_span](https://github.com/rust-lang/rust/pull/99126) |
| 195 | +- [#99123 proc_macro: use crossbeam channels for the proc_macro cross-thread bridge](https://github.com/rust-lang/rust/pull/99123) |
| 196 | +- [#99047 Rollup of 6 pull requests](https://github.com/rust-lang/rust/pull/99047) |
| 197 | +- [#99014 Rollup of 8 pull requests](https://github.com/rust-lang/rust/pull/99014) |
| 198 | +- [#98987 Rollup of 7 pull requests](https://github.com/rust-lang/rust/pull/98987) |
| 199 | +- [#98957 don't allow ZST in ScalarInt ](https://github.com/rust-lang/rust/pull/98957) |
| 200 | +- [#98904 Rollup of 8 pull requests](https://github.com/rust-lang/rust/pull/98904) |
| 201 | +- [#98874 Rollup of 5 pull requests](https://github.com/rust-lang/rust/pull/98874) |
| 202 | +- [#98851 rustc_metadata: dedupe strings to prevent multiple copies in rmeta/query cache blow file size](https://github.com/rust-lang/rust/pull/98851) |
| 203 | +- [#98612 Rollup of 9 pull requests](https://github.com/rust-lang/rust/pull/98612) |
| 204 | +- [#98591 Rollup of 9 pull requests](https://github.com/rust-lang/rust/pull/98591) |
| 205 | +- [#98178 btree: avoid forcing the allocator to be a reference](https://github.com/rust-lang/rust/pull/98178) |
| 206 | +- [#98145 Pull Derefer before ElaborateDrops](https://github.com/rust-lang/rust/pull/98145) |
| 207 | +- [#97786 Account for `-Z simulate-remapped-rust-src-base` when resolving remapped paths](https://github.com/rust-lang/rust/pull/97786) |
| 208 | +- [#97019 Transition to valtrees pt1](https://github.com/rust-lang/rust/pull/97019) |
| 209 | +- [#96883 Add EarlyBinder](https://github.com/rust-lang/rust/pull/96883) |
| 210 | +- [#96825 Retire `ItemLikeVisitor` trait](https://github.com/rust-lang/rust/pull/96825) |
| 211 | +- [#96010 Implement `core::ptr::Unique` on top of `NonNull`](https://github.com/rust-lang/rust/pull/96010) |
| 212 | +- [#95990 Rollup of 7 pull requests](https://github.com/rust-lang/rust/pull/95990) |
| 213 | +- [#95956 Support unstable moves via stable in unstable items](https://github.com/rust-lang/rust/pull/95956) |
| 214 | +- [#95899 rustc_metadata: Do not encode unnecessary module children](https://github.com/rust-lang/rust/pull/95899) |
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