Re: [PATCH v3 8/8] riscv: lib: add strrchr implementation

Andy Shevchenko
2026-01-20T07:32:28Z

On Tue, Jan 20, 2026 at 02:58:52PM +0800, Feng Jiang wrote:
> Add an assembly implementation of strrchr() for RISC-V.
>
> This implementation minimizes instruction count and avoids unnecessary
> memory access to the stack. The performance benefits are most visible
> on small workloads (1-16 bytes) where the architectural savings in
> function overhead outweigh the execution time of the scan loop.
>
> Benchmark results (QEMU TCG, rv64):
> Length | Original (MB/s) | Optimized (MB/s) | Improvement
> -------|-----------------|------------------|------------
> 1 B | 21 | 22 | +4.7%
> 7 B | 116 | 122 | +5.1%
> 16 B | 195 | 208 | +6.6%
> 512 B | 388 | 399 | +2.8%
> 4096 B | 411 | 411 | +0.0%

> Suggested-by: Andy Shevchenko <andy@kernel.org>

Wrong tag.

--
With Best Regards,
Andy Shevchenko