Gearhash gets a 2× speedup on ARM64 with a NEON backend
Speeding up gearhash on ARM64
The gearhash crate's new NEON backend makes it roughly twice as fast on ARM64 at typical chunk sizes, selected automatically on aarch64. The author details the journey from a disappointing 0.92× direct port to 1.81×, overcoming the serial dependency chain and compiler reassociation. Benchmarks show speedups up to 2.17× for larger chunks, and the crate now powers Hugging Face's Xet client with 10k–20k daily downloads.
You cannot stop the compiler reassociating a sum, but you can (try to) stop it seeing one.