Re: [PATCH 0/4] RISC-V CRC optimizations

Eric Biggers
2025-02-24T18:06:16Z

On Sun, Feb 16, 2025 at 02:55:26PM -0800, Eric Biggers wrote:
> This patchset is a replacement for
> "[PATCH v4] riscv: Optimize crct10dif with Zbc extension"
> (https://lore.kernel.org/r/20250211071101.181652-1-zhihang.shao.iscas@gmail.com/).
> It adopts the approach that I'm taking for x86 where code is shared
> among CRC variants. It replaces the existing Zbc optimized CRC32
> functions, then adds Zbc optimized CRC-T10DIF and CRC64 functions.
>
> This new code should be significantly faster than the current Zbc
> optimized CRC32 code and the previously proposed CRC-T10DIF code. It
> uses "folding" instead of just Barrett reduction, and it also implements
> Barrett reduction more efficiently.
>
> This applies to crc-next at
> https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=crc-next.
> It depends on other patches that are queued there for 6.15, so I plan to
> take it through there if there are no objections.
>
> Tested with crc_kunit in QEMU (set CONFIG_CRC_KUNIT_TEST=y and
> CONFIG_CRC_BENCHMARK=y), both 32-bit and 64-bit. I don't have real Zbc
> capable hardware to benchmark this on, but the new code should work very
> well; similar optimizations work very well on other architectures.

Any feedback on this series from the RISC-V side?

- Eric