From 0240e5a9431cb48f980fd44f913d7f0886b0aded Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Thu, 24 Apr 2025 18:41:26 +0200 Subject: [PATCH] selftests/bpf: Fix arena_spin_lock on systems with less than 16 CPUs test_arena_spin_lock_size() explicitly requires having at least 2 CPUs, but if the machine has less than 16, then pthread_setaffinity_np() call in spin_lock_thread() fails. Cap threads to the number of CPUs. Alternative solutions are raising the number of required CPUs to 16, or pinning multiple threads to the same CPU, but they are not that useful. Signed-off-by: Ilya Leoshkevich Link: https://lore.kernel.org/r/20250424165525.154403-3-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/arena_spin_lock.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c index 7565fc7690c2..0223fce4db2b 100644 --- a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c +++ b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c @@ -51,9 +51,11 @@ static void test_arena_spin_lock_size(int size) struct arena_spin_lock *skel; pthread_t thread_id[16]; int prog_fd, i, err; + int nthreads; void *ret; - if (get_nprocs() < 2) { + nthreads = MIN(get_nprocs(), ARRAY_SIZE(thread_id)); + if (nthreads < 2) { test__skip(); return; } @@ -66,25 +68,25 @@ static void test_arena_spin_lock_size(int size) goto end; } skel->bss->cs_count = size; - skel->bss->limit = repeat * 16; + skel->bss->limit = repeat * nthreads; - ASSERT_OK(pthread_barrier_init(&barrier, NULL, 16), "barrier init"); + ASSERT_OK(pthread_barrier_init(&barrier, NULL, nthreads), "barrier init"); prog_fd = bpf_program__fd(skel->progs.prog); - for (i = 0; i < 16; i++) { + for (i = 0; i < nthreads; i++) { err = pthread_create(&thread_id[i], NULL, &spin_lock_thread, &prog_fd); if (!ASSERT_OK(err, "pthread_create")) goto end_barrier; } - for (i = 0; i < 16; i++) { + for (i = 0; i < nthreads; i++) { if (!ASSERT_OK(pthread_join(thread_id[i], &ret), "pthread_join")) goto end_barrier; if (!ASSERT_EQ(ret, &prog_fd, "ret == prog_fd")) goto end_barrier; } - ASSERT_EQ(skel->bss->counter, repeat * 16, "check counter value"); + ASSERT_EQ(skel->bss->counter, repeat * nthreads, "check counter value"); end_barrier: pthread_barrier_destroy(&barrier); -- 2.50.1