linux-kernel - [PATCH v3 5/8] lib/string_kunit: extend benchmarks to strnlen and chr searches

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Message-Id: <20260120065852.166857-6-jiangfeng@kylinos.cn>
Date: Tue, 20 Jan 2026 14:58:49 +0800
From: Feng Jiang <jiangfeng@...inos.cn>
To: pjw@...nel.org,
	palmer@...belt.com,
	aou@...s.berkeley.edu,
	alex@...ti.fr,
	akpm@...ux-foundation.org,
	kees@...nel.org,
	andy@...nel.org,
	jiangfeng@...inos.cn,
	ebiggers@...nel.org,
	martin.petersen@...cle.com,
	ardb@...nel.org,
	charlie@...osinc.com,
	conor.dooley@...rochip.com,
	ajones@...tanamicro.com,
	linus.walleij@...aro.org,
	nathan@...nel.org
Cc: linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-hardening@...r.kernel.org,
	Joel Stanley <joel@....id.au>
Subject: [PATCH v3 5/8] lib/string_kunit: extend benchmarks to strnlen and chr searches

Extend the string benchmarking suite to include strnlen(), strchr(),
and strrchr().

For character search functions (strchr and strrchr), the benchmark
targets the null terminator. This ensures the entire string is scanned,
providing a consistent measure of full-length processing efficiency
comparable to strlen().

Suggested-by: Andy Shevchenko <andy@...nel.org>
Suggested-by: Eric Biggers <ebiggers@...nel.org>
Tested-by: Joel Stanley <joel@....id.au>
Signed-off-by: Feng Jiang <jiangfeng@...inos.cn>
---
 lib/tests/string_kunit.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c
index e20e924d1c67..9d76777ad753 100644
--- a/lib/tests/string_kunit.c
+++ b/lib/tests/string_kunit.c
@@ -850,6 +850,21 @@ static void string_bench_strlen(struct kunit *test)
 	STRING_BENCH_BUF(test, buf, len, strlen, buf);
 }
 
+static void string_bench_strnlen(struct kunit *test)
+{
+	STRING_BENCH_BUF(test, buf, len, strnlen, buf, len);
+}
+
+static void string_bench_strchr(struct kunit *test)
+{
+	STRING_BENCH_BUF(test, buf, len, strchr, buf, '\0');
+}
+
+static void string_bench_strrchr(struct kunit *test)
+{
+	STRING_BENCH_BUF(test, buf, len, strrchr, buf, '\0');
+}
+
 static struct kunit_case string_test_cases[] = {
 	KUNIT_CASE(string_test_memset16),
 	KUNIT_CASE(string_test_memset32),
@@ -876,6 +891,9 @@ static struct kunit_case string_test_cases[] = {
 	KUNIT_CASE(string_test_memtostr),
 	KUNIT_CASE(string_test_strends),
 	KUNIT_CASE(string_bench_strlen),
+	KUNIT_CASE(string_bench_strnlen),
+	KUNIT_CASE(string_bench_strchr),
+	KUNIT_CASE(string_bench_strrchr),
 	{}
 };
 
-- 
2.25.1