From 88f064cb959352ef35fe099d017cc12dbfa433b0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 15 Jul 2026 16:47:39 +0200 Subject: [PATCH] raid6/kunit: add a benchmark Add a benchmark to test the RAID 6 P/Q functions for more representative block sizes and numbers of disks. This splits the maximum alloc size used for the benchmark from the max size for the kunit test because recovery is currently limited to a single page at a time. Hopefully this will be fixed soon. The runtime numbers are reported in GB/s as the numbers of modern implementations are basically unreadable as MB/s. This means retro-architectures could report 0, but that is an easy tradeoff. Link: https://lore.kernel.org/20260715144825.95432-9-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Eric Biggers Signed-off-by: Andrew Morton --- lib/raid/Kconfig | 6 +++ lib/raid/raid6/tests/raid6_kunit.c | 66 +++++++++++++++++++++++++++++- 2 files changed, 71 insertions(+), 1 deletion(-) diff --git a/lib/raid/Kconfig b/lib/raid/Kconfig index c4eeb7c716c8..01f007b2522c 100644 --- a/lib/raid/Kconfig +++ b/lib/raid/Kconfig @@ -60,6 +60,12 @@ config RAID6_PQ_KUNIT_TEST This is intended to help people writing architecture-specific optimized versions. If unsure, say N. +config RAID6_PQ_KUNIT_BENCHMARK + bool "Benchmark for RAID6 PQ" + depends on RAID6_PQ_KUNIT_TEST + help + Include benchmarks in the KUnit test suite for raid P/Q generation. + config RAID6_PQ_BENCHMARK bool "Automatically choose fastest RAID6 PQ functions" depends on RAID6_PQ diff --git a/lib/raid/raid6/tests/raid6_kunit.c b/lib/raid/raid6/tests/raid6_kunit.c index 9f3e671a1224..7d0a1ec98001 100644 --- a/lib/raid/raid6/tests/raid6_kunit.c +++ b/lib/raid/raid6/tests/raid6_kunit.c @@ -18,6 +18,7 @@ MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING"); #define RAID6_KUNIT_MAX_BUFFERS 64 /* Including P and Q */ #define RAID6_KUNIT_MAX_FAILURES 2 #define RAID6_KUNIT_MAX_BYTES PAGE_SIZE +#define RAID6_KUNIT_ALLOC_BYTES SZ_16K static struct rnd_state rng; static void *test_buffers[RAID6_KUNIT_MAX_BUFFERS]; @@ -229,6 +230,68 @@ static void raid6_test(struct kunit *test) raid6_test_one(test); } +static void raid6_benchmark(struct kunit *test) +{ + static const unsigned int nr_to_test[] = { + 4, 5, 6, 7, 8, 10, 12, 15, 16, 32, + }; + static const unsigned int len_to_test[] = { + SZ_4K, SZ_16K, + }; + unsigned int i, j, l; + u64 t; + + if (!IS_ENABLED(CONFIG_RAID6_PQ_KUNIT_BENCHMARK)) + kunit_skip(test, "not enabled"); + + /* warm-up */ + for (i = 0; i < ARRAY_SIZE(nr_to_test); i++) { + for (j = 0; j < ARRAY_SIZE(len_to_test); j++) { + for (l = 0; l < 10; l++) { + raid6_gen_syndrome(nr_to_test[i], + len_to_test[j], test_buffers); + } + } + } + + /* + * Preferably this would be a loop over len_to_test, but the kunit + * logging always adds a newline to each logged format string. + */ + static_assert(ARRAY_SIZE(len_to_test) == 2); + kunit_info(test, " \t%5u bytes\t%5u bytes\n", + len_to_test[0], len_to_test[1]); + + for (i = 0; i < ARRAY_SIZE(nr_to_test); i++) { + unsigned int nr = nr_to_test[i]; + u64 speed[ARRAY_SIZE(len_to_test)]; + + KUNIT_ASSERT_LE(test, nr, RAID6_KUNIT_MAX_BUFFERS); + + for (j = 0; j < ARRAY_SIZE(len_to_test); j++) { + unsigned int len = len_to_test[j]; + const unsigned long num_iters = 1000; + + KUNIT_ASSERT_GT(test, len, 0); + KUNIT_ASSERT_LE(test, len, RAID6_KUNIT_ALLOC_BYTES); + + preempt_disable(); + t = ktime_get_ns(); + for (l = 0; l < num_iters; l++) + raid6_gen_syndrome(nr_to_test[i], + len_to_test[j], test_buffers); + t = max(ktime_get_ns() - t, 1); + preempt_enable(); + + speed[j] = div64_u64((u64)len * num_iters * nr, t); + } + + static_assert(ARRAY_SIZE(len_to_test) == 2); + kunit_info(test, "%3u disks:\t%5llu GB/s\t%5llu GB/s\n", + nr, speed[0], speed[1]); + } +} + static const void *raid6_gen_params(struct kunit *test, const void *prev, char *desc) { @@ -256,6 +319,7 @@ next_algo: static struct kunit_case raid6_test_cases[] = { KUNIT_CASE_PARAM(raid6_test, raid6_gen_params), + KUNIT_CASE(raid6_benchmark), {}, }; @@ -270,7 +334,7 @@ static int raid6_suite_init(struct kunit_suite *suite) * so that it is immediately followed by a guard page. This allows * buffer overreads to be detected, even in assembly code. */ - test_buflen = round_up(RAID6_KUNIT_MAX_BYTES, PAGE_SIZE); + test_buflen = round_up(RAID6_KUNIT_ALLOC_BYTES, PAGE_SIZE); for (i = 0; i < RAID6_KUNIT_MAX_FAILURES; i++) { test_recov_buffers[i] = vmalloc(test_buflen); if (!test_recov_buffers[i])