From ee5cf82ce04a60d71b0dc219804f6cf1e6ba6d14 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Sat, 6 Jul 2019 11:06:26 -0700 Subject: [PATCH] selftests/bpf: test perf buffer API Add test verifying perf buffer API functionality. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann --- .../selftests/bpf/prog_tests/perf_buffer.c | 100 ++++++++++++++++++ .../selftests/bpf/progs/test_perf_buffer.c | 25 +++++ 2 files changed, 125 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_buffer.c create mode 100644 tools/testing/selftests/bpf/progs/test_perf_buffer.c diff --git a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c new file mode 100644 index 000000000000..3f1ef95865ff --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include +#include +#include +#include + +#ifdef __x86_64__ +#define SYS_KPROBE_NAME "__x64_sys_nanosleep" +#else +#define SYS_KPROBE_NAME "sys_nanosleep" +#endif + +static void on_sample(void *ctx, int cpu, void *data, __u32 size) +{ + int cpu_data = *(int *)data, duration = 0; + cpu_set_t *cpu_seen = ctx; + + if (cpu_data != cpu) + CHECK(cpu_data != cpu, "check_cpu_data", + "cpu_data %d != cpu %d\n", cpu_data, cpu); + + CPU_SET(cpu, cpu_seen); +} + +void test_perf_buffer(void) +{ + int err, prog_fd, nr_cpus, i, duration = 0; + const char *prog_name = "kprobe/sys_nanosleep"; + const char *file = "./test_perf_buffer.o"; + struct perf_buffer_opts pb_opts = {}; + struct bpf_map *perf_buf_map; + cpu_set_t cpu_set, cpu_seen; + struct bpf_program *prog; + struct bpf_object *obj; + struct perf_buffer *pb; + struct bpf_link *link; + + nr_cpus = libbpf_num_possible_cpus(); + if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus)) + return; + + /* load program */ + err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd); + if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno)) + return; + + prog = bpf_object__find_program_by_title(obj, prog_name); + if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name)) + goto out_close; + + /* load map */ + perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map"); + if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n")) + goto out_close; + + /* attach kprobe */ + link = bpf_program__attach_kprobe(prog, false /* retprobe */, + SYS_KPROBE_NAME); + if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link))) + goto out_close; + + /* set up perf buffer */ + pb_opts.sample_cb = on_sample; + pb_opts.ctx = &cpu_seen; + pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts); + if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb))) + goto out_detach; + + /* trigger kprobe on every CPU */ + CPU_ZERO(&cpu_seen); + for (i = 0; i < nr_cpus; i++) { + CPU_ZERO(&cpu_set); + CPU_SET(i, &cpu_set); + + err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), + &cpu_set); + if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n", + i, err)) + goto out_detach; + + usleep(1); + } + + /* read perf buffer */ + err = perf_buffer__poll(pb, 100); + if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err)) + goto out_free_pb; + + if (CHECK(CPU_COUNT(&cpu_seen) != nr_cpus, "seen_cpu_cnt", + "expect %d, seen %d\n", nr_cpus, CPU_COUNT(&cpu_seen))) + goto out_free_pb; + +out_free_pb: + perf_buffer__free(pb); +out_detach: + bpf_link__destroy(link); +out_close: + bpf_object__close(obj); +} diff --git a/tools/testing/selftests/bpf/progs/test_perf_buffer.c b/tools/testing/selftests/bpf/progs/test_perf_buffer.c new file mode 100644 index 000000000000..876c27deb65a --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_perf_buffer.c @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2019 Facebook + +#include +#include +#include "bpf_helpers.h" + +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __uint(key_size, sizeof(int)); + __uint(value_size, sizeof(int)); +} perf_buf_map SEC(".maps"); + +SEC("kprobe/sys_nanosleep") +int handle_sys_nanosleep_entry(struct pt_regs *ctx) +{ + int cpu = bpf_get_smp_processor_id(); + + bpf_perf_event_output(ctx, &perf_buf_map, BPF_F_CURRENT_CPU, + &cpu, sizeof(cpu)); + return 0; +} + +char _license[] SEC("license") = "GPL"; +__u32 _version SEC("version") = 1; -- 2.30.2