From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Feng Jiang <jiangfeng@kylinos.cn>,
pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu,
alex@ghiti.fr, kees@kernel.org, andy@kernel.org,
akpm@linux-foundation.org, martin.petersen@oracle.com,
ardb@kernel.org, ajones@ventanamicro.com,
conor.dooley@microchip.com, samuel.holland@sifive.com,
linus.walleij@linaro.org, nathan@kernel.org,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2 01/14] lib/string: extract generic strlen() into __generic_strlen()
Date: Wed, 14 Jan 2026 09:07:44 +0200 [thread overview]
Message-ID: <aWdAwHy77V8EiDeX@smile.fi.intel.com> (raw)
In-Reply-To: <20260114000151.GB2178@quark>
On Tue, Jan 13, 2026 at 04:01:51PM -0800, Eric Biggers wrote:
> On Tue, Jan 13, 2026 at 04:27:35PM +0800, Feng Jiang wrote:
> > To support performance benchmarking in KUnit tests, extract the
> > generic C implementation of strlen() into a standalone function
> > __generic_strlen(). This allows tests to compare architecture-optimized
> > versions against the generic baseline without duplicating code.
...
> A similar problem exists with the architecture-optimized CRC and crypto
> functions. Historically, these subsystems exported both generic and
> architecture-optimized functions.
>
> We've actually been moving away from that design to simplify things.
> For example, for CRC-32C there's now just the crc32c() function which
> delegates to the "best" CRC-32C implementation, with no direct access to
> the generic implementation of CRC-32C.
>
> crc_kunit then just tests and benchmarks crc32c(). To check how the
> performance of crc32c() changes when its implementation changes (whether
> the change is the addition of an arch-optimized implementation or a
> change in an existing arch-optimized implementation), the developer just
> needs to run crc_kunit with two kernels, before and after.
>
> I suggest just doing that. In that case there would be no need to
> export the generic implementations of these functions.
This also would work for me! Whatever, folks, you find the best from the
readability and maintenance point of view.
> (Also note that *if* the generic functions are exported, they probably
> should be exported only when the KUnit test is enabled. There's no need
> to include them in the kernel image when the test isn't enabled.)
True.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-01-14 7:07 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-13 8:27 [PATCH v2 00/14] riscv: optimize string functions and add kunit tests Feng Jiang
2026-01-13 8:27 ` [PATCH v2 01/14] lib/string: extract generic strlen() into __generic_strlen() Feng Jiang
2026-01-13 8:33 ` Andy Shevchenko
2026-01-14 0:01 ` Eric Biggers
2026-01-14 1:41 ` Feng Jiang
2026-01-14 7:07 ` Andy Shevchenko [this message]
2026-01-14 10:10 ` David Laight
2026-01-15 6:50 ` Feng Jiang
2026-01-15 6:55 ` Andy Shevchenko
2026-01-13 8:27 ` [PATCH v2 02/14] lib/string: extract generic strnlen() into __generic_strnlen() Feng Jiang
2026-01-13 8:27 ` [PATCH v2 03/14] lib/string: extract generic strchr() into __generic_strchr() Feng Jiang
2026-01-13 8:27 ` [PATCH v2 04/14] lib/string: extract generic strrchr() into __generic_strrchr() Feng Jiang
2026-01-13 8:27 ` [PATCH v2 05/14] lib/string_kunit: add correctness test for strlen Feng Jiang
2026-01-13 8:27 ` [PATCH v2 06/14] lib/string_kunit: add correctness test for strnlen Feng Jiang
2026-01-13 8:41 ` Andy Shevchenko
2026-01-13 8:27 ` [PATCH v2 07/14] lib/string_kunit: add correctness test for strrchr() Feng Jiang
2026-01-13 8:27 ` [PATCH v2 08/14] lib/string_kunit: add performance benchmark for strlen() Feng Jiang
2026-01-13 8:46 ` Andy Shevchenko
2026-01-14 6:14 ` Feng Jiang
2026-01-14 7:04 ` Feng Jiang
2026-01-14 7:21 ` Andy Shevchenko
2026-01-14 8:05 ` Feng Jiang
2026-01-14 10:21 ` David Laight
2026-01-15 6:24 ` Feng Jiang
2026-01-15 10:40 ` David Laight
2026-01-18 11:11 ` kernel test robot
2026-01-13 8:27 ` [PATCH v2 09/14] lib/string_kunit: add performance benchmark for strnlen() Feng Jiang
2026-01-13 8:27 ` [PATCH v2 10/14] lib/string_kunit: add performance benchmark for strchr() Feng Jiang
2026-01-13 8:27 ` [PATCH v2 11/14] lib/string_kunit: add performance benchmark for strrchr() Feng Jiang
2026-01-13 8:27 ` [PATCH v2 12/14] riscv: lib: add strnlen implementation Feng Jiang
2026-01-13 8:48 ` Andy Shevchenko
2026-01-13 8:27 ` [PATCH v2 13/14] riscv: lib: add strchr implementation Feng Jiang
2026-01-13 8:27 ` [PATCH v2 14/14] riscv: lib: add strrchr implementation Feng Jiang
2026-01-13 8:52 ` [PATCH v2 00/14] riscv: optimize string functions and add kunit tests Andy Shevchenko
2026-01-15 4:43 ` Joel Stanley
2026-01-19 9:24 ` Feng Jiang
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