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Message-ID: <20190706180628.3919653-4-andriin@fb.com>
Date: Sat, 6 Jul 2019 11:06:26 -0700
From: Andrii Nakryiko <andriin@...com>
To: <andrii.nakryiko@...il.com>, <bpf@...r.kernel.org>,
<netdev@...r.kernel.org>, <ast@...com>, <daniel@...earbox.net>,
<kernel-team@...com>
CC: Andrii Nakryiko <andriin@...com>
Subject: [PATCH v7 bpf-next 3/5] selftests/bpf: test perf buffer API
Add test verifying perf buffer API functionality.
Signed-off-by: Andrii Nakryiko <andriin@...com>
Acked-by: Song Liu <songliubraving@...com>
Acked-by: Yonghong Song <yhs@...com>
---
.../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 <pthread.h>
+#include <sched.h>
+#include <sys/socket.h>
+#include <test_progs.h>
+
+#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 <linux/ptrace.h>
+#include <linux/bpf.h>
+#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;
--
2.17.1
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