crc64fast-nvme

SIMD-accelerated carryless-multiplication CRC-64/NVME checksum computation (similar to crc32fast and forked from crc64fast which calculates CRC-64/XZ [a.k.a CRC-64/GO-ECMA]).

CRC-64/NVME comes from the NVM Express® NVM Command Set Specification (Revision 1.0d, December 2023) and has also been implemented in the Linux kernel (where it's called CRC-64/Rocksoft). Note that the Check value in the spec is incorrect (Section 5.2.1.3.4, Figure 120, page 83).

SIMD-accelerated carryless-multiplication is based on the Intel Fast CRC Computation for Generic Polynomials Using PCLMULQDQ Instruction paper.

Changes from crc64fast

Primarily changes the CRC-64/XZ (aka CRC-64/GO-ECMA) polynomial from crc64fast (which uses the ECMA-182 polynomial 0x42F0E1EBA9EA3693) to use the NVME polynomial (0xAD93D23594C93659), plus re-calculates the input parameters (tables, keys, mu, and reciprocal polynomial) for carryless-multiplication.

Usage

use crc64fast_nvme::Digest;

let mut c = Digest::new();
c.write(b"hello ");
c.write(b"world!");
let checksum = c.sum64();
assert_eq!(checksum, 0xd9160d1fa8e418e3);

CLI example

A simple CLI implementation can be found in crc_64_nvme_checksum.rs, which will calculate the CRC-64/NVME checksum for a file on disk.

Other CRC-64 implementations

Tooling to re-calculate input parameters for other CRC-64 implementations/polynomials is supplied in src\bin.

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)

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)