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Message-ID: <20190625232601.3227055-3-andriin@fb.com>
Date: Tue, 25 Jun 2019 16:26:01 -0700
From: Andrii Nakryiko <andriin@...com>
To: <andrii.nakryiko@...il.com>, <ast@...com>, <daniel@...earbox.net>,
<bpf@...r.kernel.org>, <netdev@...r.kernel.org>,
<kernel-team@...com>
CC: Andrii Nakryiko <andriin@...com>
Subject: [PATCH bpf-next 2/2] selftests/bpf: test perf buffer API
Add test verifying perf buffer API functionality.
Signed-off-by: Andrii Nakryiko <andriin@...com>
---
.../selftests/bpf/prog_tests/perf_buffer.c | 86 +++++++++++++++++++
.../selftests/bpf/progs/test_perf_buffer.c | 31 +++++++
2 files changed, 117 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..3ba3e26141ac
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <pthread.h>
+#include <sched.h>
+#include <sys/socket.h>
+#include <test_progs.h>
+
+static void on_sample(void *ctx, void *data, __u32 size)
+{
+ cpu_set_t *cpu_seen = ctx;
+ int cpu = *(int *)data;
+
+ CPU_SET(cpu, cpu_seen);
+}
+
+void test_perf_buffer(void)
+{
+ int err, prog_fd, prog_pfd, nr_cpus, i, duration = 0;
+ const char *prog_name = "kprobe/sys_nanosleep";
+ const char *file = "./test_perf_buffer.o";
+ 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;
+
+ 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 */
+ prog_pfd = bpf_program__attach_kprobe(prog, false /* retprobe */,
+ "sys_nanosleep");
+ if (CHECK(prog_pfd < 0, "attach_kprobe", "err %d\n", prog_pfd))
+ goto out_close;
+
+ /* set up perf buffer */
+ pb = perf_buffer__new(perf_buf_map, 1, on_sample, NULL, &cpu_seen);
+ 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:
+ libbpf_perf_event_disable_and_close(prog_pfd);
+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..ba961f608fd5
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_perf_buffer.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+
+#include <linux/ptrace.h>
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+struct {
+ int type;
+ int key_size;
+ int value_size;
+ int max_entries;
+} perf_buf_map SEC(".maps") = {
+ .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
+ .key_size = sizeof(int),
+ .value_size = sizeof(int),
+ .max_entries = 56,
+};
+
+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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