README.md

crc64fast

SIMD-accelerated CRC-64/XZ (a.k.a. CRC-64/GO-ECMA) computation (similar to crc32fast).

Usage

use crc64fast::Digest;

let mut c = Digest::new();
c.write(b"hello ");
c.write(b"world!");
let checksum = c.sum64();
assert_eq!(checksum, 0x8483_c0fa_3260_7d61);

Performance

crc64fast provides two fast implementations, and the most performance one will be chosen based on CPU feature at runtime.

• a fast, platform-agnostic table-based implementation, processing 16 bytes at a time.
• a SIMD-carryless-multiplication based implementation on modern processors:
  • using PCLMULQDQ + SSE 4.1 on x86/x86_64
  • using PMULL + NEON on AArch64 (64-bit ARM)

Algorithm	Throughput (x86_64)	Throughput (aarch64)
crc 3.0.1	0.5 GiB/s	0.3 GiB/s
crc64fast (table)	2.3 GiB/s	1.8 GiB/s
crc64fast (simd)	28.2 GiB/s	20.0 GiB/s

TODO

This crate is mainly intended for use in TiKV only. Features beyond AArch64 are unlikely to be implemented.

• AArch64 support based on PMULL
• no_std support
• Fuzz test
• Custom polynomial

License

crc64fast is dual-licensed under

• Apache 2.0 license (LICENSE-Apache or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)