From 305715779517b1a04351d1b1b3cd66f211e23f2f Mon Sep 17 00:00:00 2001 From: Ryan Levick Date: Wed, 16 Jun 2021 14:13:05 +0200 Subject: [PATCH] Add triage for 2021-06-16 --- triage/2021-06-16.md | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 triage/2021-06-16.md diff --git a/triage/2021-06-16.md b/triage/2021-06-16.md new file mode 100644 index 000000000..6b0c151a5 --- /dev/null +++ b/triage/2021-06-16.md @@ -0,0 +1,31 @@ +# 2021-06-16 Triage Log + +The highlight of this week was a huge performance gains in some async focused benchmarks from only pretty-printing generator witness in verbose mode. This improved async heavy benchmarks by as much as 75%. + +Triage done by **@rylev**. +Revision range: [a50d72158e08e02cfc051b863017bdbd2c45b637..d192c80d2284ba6b5146bb3da586354c3762c72b](https://perf.rust-lang.org/?start=a50d72158e08e02cfc051b863017bdbd2c45b637&end=d192c80d2284ba6b5146bb3da586354c3762c72b&absolute=false&stat=instructions%3Au) + +1 Regressions, 2 Improvements, 0 Mixed +0 of them in rollups + +#### Regressions + +Make copy/copy_nonoverlapping fn's again [#86003](https://github.com/rust-lang/rust/issues/86003) +- Moderate regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=47d38752c65359e1f4558d7a06935982fb8b486f&end=eab201df7028ebb6812c0b1a01702ac6ecfcceed&stat=instructions:u) (up to 2.3% on `incr-patched: u8 3072` builds of `issue-46449-debug`) +- Regressions happening mostly in LLVM codegen which makes sense given that this moves from intrinsics to function calls which should produce more LLVM IR. +- Follow up conversation starts [here](https://github.com/rust-lang/rust/pull/86003#issuecomment-862210554). + +#### Improvements + +Update cargo [#86207](https://github.com/rust-lang/rust/issues/86207) +- Moderate improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=24bdc6d73a75dce9a7013ebc7c037013ff4ea099&end=302468e71c39021df8778219e3bf9bee40e7de88&stat=instructions:u) (up to -1.2% on `full` builds of `deep-vector-debug`) + +Pretty print generator witness only in `-Zverbose` mode [#86240](https://github.com/rust-lang/rust/issues/86240) +- Very large improvement in [instruction counts](https://perf.rust-lang.org/compare.html?start=da7ada584a3e5c3467b8b9f344b4a0f2a81ce32a&end=24bdc6d73a75dce9a7013ebc7c037013ff4ea099&stat=instructions:u) (up to -75.8% on `incr-full` builds of `deeply-nested-async-opt`) +- Moderate regression in [instruction counts](https://perf.rust-lang.org/compare.html?start=da7ada584a3e5c3467b8b9f344b4a0f2a81ce32a&end=24bdc6d73a75dce9a7013ebc7c037013ff4ea099&stat=instructions:u) (up to 1.3% on `full` builds of `deep-vector-debug`) +- Huge performance gains in some benchmarks with a small regression in one benchmark. It's hard to see why the regression is happening since this change is strictly less work for the compiler in all cases. This was originally classified as "mixed" but it feels more appropriate as an improvement. + +#### Nags requiring follow up + +* Follow up from last week on regression in [#85343](https://github.com/rust-lang/rust/pull/85343#issuecomment-856819536) +* Follow up to regression in [#86003](https://github.com/rust-lang/rust/pull/86003#issuecomment-862210554).