From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Feng Jiang <jiangfeng@kylinos.cn>
Cc: pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu,
alex@ghiti.fr, akpm@linux-foundation.org, kees@kernel.org,
andy@kernel.org, ebiggers@kernel.org, martin.petersen@oracle.com,
ardb@kernel.org, charlie@rivosinc.com,
conor.dooley@microchip.com, ajones@ventanamicro.com,
linus.walleij@linaro.org, nathan@kernel.org,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org, Joel Stanley <joel@jms.id.au>
Subject: Re: [PATCH v3 8/8] riscv: lib: add strrchr implementation
Date: Tue, 20 Jan 2026 09:32:21 +0200 [thread overview]
Message-ID: <aW8vhU-ECUIITPoh@smile.fi.intel.com> (raw)
In-Reply-To: <20260120065852.166857-9-jiangfeng@kylinos.cn>
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
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next prev parent reply other threads:[~2026-01-20 7:32 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 6:58 [PATCH v3 0/8] riscv: optimize string functions and add kunit tests Feng Jiang
2026-01-20 6:58 ` [PATCH v3 1/8] lib/string_kunit: add correctness test for strlen Feng Jiang
2026-01-20 7:28 ` Andy Shevchenko
2026-01-20 6:58 ` [PATCH v3 2/8] lib/string_kunit: add correctness test for strnlen Feng Jiang
2026-01-20 7:29 ` Andy Shevchenko
2026-01-20 6:58 ` [PATCH v3 3/8] lib/string_kunit: add correctness test for strrchr() Feng Jiang
2026-01-20 7:30 ` Andy Shevchenko
2026-01-20 6:58 ` [PATCH v3 4/8] lib/string_kunit: add performance benchmarks for strlen Feng Jiang
2026-01-20 7:46 ` Andy Shevchenko
2026-01-21 5:45 ` Feng Jiang
2026-01-20 6:58 ` [PATCH v3 5/8] lib/string_kunit: extend benchmarks to strnlen and chr searches Feng Jiang
2026-01-20 7:48 ` Andy Shevchenko
2026-01-21 5:48 ` Feng Jiang
2026-01-20 6:58 ` [PATCH v3 6/8] riscv: lib: add strnlen implementation Feng Jiang
2026-01-20 7:31 ` Andy Shevchenko
2026-01-21 5:52 ` Feng Jiang
2026-01-21 7:24 ` Qingfang Deng
2026-01-23 1:28 ` Feng Jiang
2026-01-20 6:58 ` [PATCH v3 7/8] riscv: lib: add strchr implementation Feng Jiang
2026-01-20 7:31 ` Andy Shevchenko
2026-01-20 6:58 ` [PATCH v3 8/8] riscv: lib: add strrchr implementation Feng Jiang
2026-01-20 7:32 ` Andy Shevchenko [this message]
2026-01-20 7:36 ` [PATCH v3 0/8] riscv: optimize string functions and add kunit tests Andy Shevchenko
2026-01-21 6:44 ` Feng Jiang
2026-01-21 7:01 ` Andy Shevchenko
2026-01-21 8:12 ` Feng Jiang
2026-01-21 10:57 ` David Laight
2026-01-23 3:12 ` Feng Jiang
2026-01-23 10:16 ` David Laight
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