2021-01-05 Triage Log
Happy New Year! A slow week to start off the new year, with by far the most exciting development being the large gains in the ctfe benchmark caused by changes in serialization and deserialization.
Triage done by @rylev. Revision range: e2a2592885539ca97bfb1232669e7519a0c0703b..f4b9d32ef53c0629732ee131b640920ae12d1edb
0 Regressions, 2 Improvements, 2 Mixed 2 of them in rollups
Improvements
Implement edition-based macro :pat feature #80459
- Moderate improvement in instruction counts (up to -1.7% on
incr-unchanged builds of deep-vector-check) - Fixes the perf regression from #80100
rustc_serialize: specialize opaque encoding and decoding of some u8 sequences #80115
- Very large improvement in instruction counts (up to -85.1% on
incr-unchanged builds of ctfe-stress-4-check) - In rustc-serialize, specialize encoding and decoding of some contiguous u8 sequences to use a more efficient implementation.
Mixed
Rollup of 9 pull requests #80530
- Moderate regression in instruction counts (up to 2.6% on
full builds of ripgrep-opt) - Moderate improvement in instruction counts (up to -1.5% on
incr-patched: println builds of cargo-debug) - #78934 was responsible for the issue. An investigation into what exactly is the cause will happen, but the regression is not severe enough to warrant a revert.
Rollup of 12 pull requests #80708
- Large regression in instruction counts (up to 5.9% on
incr-unchanged builds of deeply-nested-async-check) - Moderate improvement in instruction counts (up to -1.4% on
full builds of coercions-debug) - The regression outweighs the improvement
- #80538 was responsible for the issue. An investigation into what exactly is the cause will happen, but the regression is not severe enough to warrant a revert.
Nags requiring follow up
- stdarch is still a major contributor to libcore compile times.