| # 2021-06-08 Triage Log |
| |
| Some good improvements, and a few regressions. No large changes. |
| |
| Triage done by **@simulacrum**. |
| Revision range: [1160cf864f2a0014e3442367e1b96496bfbeadf4..a50d72158e08e02cfc051b863017bdbd2c45b637](https://perf.rust-lang.org/?start=1160cf864f2a0014e3442367e1b96496bfbeadf4&end=a50d72158e08e02cfc051b863017bdbd2c45b637&absolute=false&stat=instructions%3Au) |
| |
| 3 Regressions, 3 Improvements, 1 Mixed |
| 1 of them in rollups |
| |
| #### Regressions |
| |
| Always go through the expn_that_defined query. [#86002](https://github.com/rust-lang/rust/issues/86002) |
| - Moderate regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=ac3e680193a3e11e60b07840ffb1db12793de110&end=6c2dd251bbff03c7a3092d43fb5b637eca0810e3&stat=instructions:u) (up to 1.6% on `incr-patched: println` builds of `webrender-check`) |
| - Necessary for correctness, regresions largely limited to incremental. |
| |
| Add variance-related information to lifetime error messages [#85343](https://github.com/rust-lang/rust/issues/85343) |
| - Moderate regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=5b638c1d3751b7ab31cac9739add516bdf39e10a&end=35fff69d043b1c0f5c29894e7f4b0da8b039c131&stat=instructions:u) (up to 4.3% on `full` builds of `wg-grammar-check`) |
| - Seems to potentially be necessary, but difference from PR run suggests more |
| can possibly be done to avoid some of the losses noted on the final merge. |
| |
| Revert "Merge CrateDisambiguator into StableCrateId" [#85891](https://github.com/rust-lang/rust/issues/85891) |
| - Moderate regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=022720bfccd46400e69def42f4647fe4059ad951&end=2312ff1a850db449b79fd3c4b215395cd2598c25&stat=instructions:u) (up to 4.9% on `full` builds of `html5ever-opt`) |
| - Reverted due to performance concerns on the original PR ([#85804]), but does |
| not seem to have recovered performance. Suggested path is to re-land but with |
| measurements the original PR; potentially there are some performance |
| improvements that can be done there as well. |
| |
| [#85804]: https://github.com/rust-lang/rust/pull/85804 |
| |
| #### Improvements |
| |
| Remove CrateNum::ReservedForIncrCompCache [#85829](https://github.com/rust-lang/rust/issues/85829) |
| - Very large improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=7f9ab0300cd66f6f616e03ea90b2d71af474bf28&end=625d5a693e4697bcafdd34fd1a38c281acabb8e9&stat=instructions:u) (up to -11.2% on `full` builds of `deeply-nested-async-debug`) |
| - Unclear what the exact cause of the large improvement is. It may be worth |
| investigating, as at first glance the change does not seem like it should have |
| such strong effects. |
| |
| Only compute the trait map once [#85905](https://github.com/rust-lang/rust/issues/85905) |
| - Moderate improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=c4f186f0ea443db4aacdd90a2515632c20ccd3fe&end=d20b9add05d32761abad651f568f1b1831cb8cf6&stat=instructions:u) (up to -1.6% on `incr-unchanged` builds of `cranelift-codegen-check`) |
| |
| Miscellaneous inlining improvements [#85892](https://github.com/rust-lang/rust/issues/85892) |
| - Moderate improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=7350f655ef7e1b00f287eca6f8c0016a8985900c&end=1e13a9bb33debb931d603278b7f1a706b0d11660&stat=instructions:u) (up to -2.2% on `full` builds of `ctfe-stress-4-check`) |
| |
| #### Mixed |
| |
| Rollup of 13 pull requests [#85952](https://github.com/rust-lang/rust/issues/85952) |
| - Moderate improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=016e9b5e33ef1407bffb575ec63d24241912556d&end=a93699f20a433797a4b84787b9652300dd7b2ad2&stat=instructions:u) (up to -4.8% on `full` builds of `html5ever-opt`) |
| - Moderate regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=016e9b5e33ef1407bffb575ec63d24241912556d&end=a93699f20a433797a4b84787b9652300dd7b2ad2&stat=instructions:u) (up to 2.9% on `incr-patched: println` builds of `cargo-opt`) |
| - Predominantly an improvement, some incremental regressions; does not appear |
| worthwhile to investigate in depth the exact cause. |
| |
| #### Nags requiring follow up |
| |
| * Follow up on regression in [#85343](https://github.com/rust-lang/rust/pull/85343#issuecomment-856819536) |
