This is a small comparison of a Rust / Wasm hash using 256bit xxhash vs. the browser's built in SHA-256.
This is not a fair comparison: this is comparing a 256-bit cryptographic hash vs a 128-bit non-cryptographic hash. But I just want a quick way to generate a checksum for files so I just want to know what's faster.
On the same hardware SHA-256 is typically slower, some figures online say 15x slower, than xxhash. But given that the browser's implementation will be implemented in native code I wanted to see how it fares vs a faster algorithm in WebAssembly.
These measurements are informally taken.
The results for xxh3_128 include the time to copy the data to the Wasm memory because that's how it'd be used in practice. This means this experiment measures the practical performance of Rust / Wasm xxh3_128, not the raw execution time.
In terms of the network overhead of loading the Wasm binary the size is only 20kb (see the cargo.toml for compile flags set to keep the binary smaller).
Measured on my M1 Macbook Air:
Chrome SHA-256: ~1.7ms
Chrome Wasm/Rust/xxh3_128: ~0.6ms
Firefox SHA-256: ~2.7 ms
Firefox Wasm/Rust/xxh3_128: ~0.6ms
Safari: Precision of performance.now() appears to be rounded too aggressively to make results meaningful.
I attempted to see if enabling Wasm-SIMD changed anything (see build_simd.sh), but it didn't seem to meaningfully impact performance.
I'm not sure if this is because the xxhash-rust isn't set up to use Wasm-SIMD or because I did something wrong.
Further research required!