SpookyHash is a fast and thorough 128-bit noncryptographic hash function by Bob Jenkins (me) in 2012. It does not use SIMD instructions, it's just normal 64-bit arithmetic, plus xor barrelshift, allowing a lot of instruction-level parallelism.
Documentation: https://burtleburtle.net/bob/hash/spooky.html .
Claude made a Rust translation in the rust/ directory. It produces identical hashes to the C++ implementation. Throughput below is from DoTimingSmall (10 million iterations, cached, on one machine); C++ compiled with g++ -O3, Rust with cargo build --release.
| bytes | C++ GB/s | Rust GB/s |
|---|---|---|
| 1 | 0.19 | 0.14 |
| 2 | 0.38 | 0.27 |
| 4 | 0.70 | 0.56 |
| 8 | 1.47 | 1.14 |
| 16 | 1.44 | 1.29 |
| 32 | 2.90 | 2.44 |
| 64 | 3.83 | 3.34 |
| 128 | 4.54 | 3.98 |
| 256 | 6.16 | 6.02 |
| 512 | 9.33 | 8.92 |
| 1024 | 12.83 | 12.27 |
| 2048 | 15.85 | 14.89 |
| 4096 | 17.82 | 16.97 |
| 8192 | 18.68 | 18.03 |
| 16384 | 19.54 | 18.62 |
Running it 16 ways in parallel (on a 16-core processor) was 6.5GB/sec per process, or 105GB/sec total.