There is an interesting pull request trying to improve the performance of sort: Improve performance of stable sort by Voultapher · Pull Request #100856 · rust-lang/rust · GitHub. Is there a official set of benchmark tests for sort?
I created some sorting benchmarks for algorithm variations I was testing. They're at gidsort/bench.rs at master · jongiddy/gidsort · GitHub
I think that I originally based these on the benchmarks provided when
sort_unstable was added.
Most of the variations of stable sort that I have seen, including mine, can beat the library version on some partially ordered patterns, but lose badly for random data.