| # 2021-04-06 Triage Log |
| |
| A pretty major week for [memory usage improvements], while wall time performance |
| largely stayed neutral, with an average of ~20% gains on memory usage for |
| release builds, and 5% on check builds, due to an update in the default allocator |
| used (to a more recent jemalloc). |
| |
| Triage done by **@simulacrum**. |
| Revision range: [4896450e7e0a522486b4d3a8d360ac4e1d2072a0..d32238532138485c80db4f2cd596372bce214e00](https://perf.rust-lang.org/?start=4896450e7e0a522486b4d3a8d360ac4e1d2072a0&end=d32238532138485c80db4f2cd596372bce214e00&absolute=false&stat=instructions%3Au) |
| |
| [memory usage improvements]: https://perf.rust-lang.org/?start=4896450e7e0a522486b4d3a8d360ac4e1d2072a0&end=d32238532138485c80db4f2cd596372bce214e00&absolute=false&stat=max-rss |
| |
| 1 Regressions, 4 Improvements, 0 Mixed |
| |
| #### Regressions |
| |
| add OR_PATTERNS_BACK_COMPAT lint [#83468](https://github.com/rust-lang/rust/issues/83468) |
| - Moderate regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=a207871d5c22f89093085da89becbb636a45ef89&end=36bcf4069717b9dff90270d13b53a3b130329960&stat=instructions:u) (up to 1.2% on `incr-patched: println` builds of `coercions-debug`) |
| - Relatively small hit on a number of benchmarks. Likely largely unavoidable. |
| |
| #### Improvements |
| |
| Stream the dep-graph to a file instead of storing it in-memory [#82780](https://github.com/rust-lang/rust/pull/82780) |
| - Large improvement in [memory usage](https://perf.rust-lang.org/compare.html?start=803ddb83598838fb9de308d283b759ba463e5e80&end=d474075a8f28ae9a410e95d849d009006db4b176&stat=max-rss) |
| |
| panic early when `TrustedLen` indicates a `length > usize::MAX` [#83726](https://github.com/rust-lang/rust/issues/83726) |
| - Large improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=49e1ec09952c5ab7798addd29532d44dc020283f&end=803ddb83598838fb9de308d283b759ba463e5e80&stat=instructions:u) (up to -7.9% on `incr-patched: compile one` builds of `regex-debug`) |
| |
| Use tikv-jemallocator in rustc/rustdoc in addition to jemalloc-sys when enabled. [#83152](https://github.com/rust-lang/rust/issues/83152) |
| - Large improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=d203fceeb12f8c0e3123fc45036575018d2f990a&end=d32238532138485c80db4f2cd596372bce214e00&stat=instructions:u) (up to -5.4% on `incr-unchanged` builds of `deep-vector-check`) |
| - Pretty nice improvements to instruction counts, though not a major contributor |
| to wall times it seems. |
| |
| Stream the dep-graph to a file instead of storing it in-memory. [#82780](https://github.com/rust-lang/rust/issues/82780) |
| - Moderate improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=803ddb83598838fb9de308d283b759ba463e5e80&end=d474075a8f28ae9a410e95d849d009006db4b176&stat=instructions:u) (up to -1.8% on `incr-full` builds of `unused-warnings-check`) |
| |
| #### Mixed |
| |
| - None |
| |
| #### Nags requiring follow up |
| |
| - The [issue](https://github.com/rust-lang/rust/pull/82964#issuecomment-800663588) from three weeks ago has stalled. |
| Likely this needs someone to mentor the author, or to take over the |
| investigation. |
