1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3#define _GNU_SOURCE
4#include <pthread.h>
5#include <sched.h>
6#include <test_progs.h>
7#include "test_perf_link.skel.h"
8
9static void burn_cpu(void)
10{
11	volatile int j = 0;
12	cpu_set_t cpu_set;
13	int i, err;
14
15	/* generate some branches on cpu 0 */
16	CPU_ZERO(&cpu_set);
17	CPU_SET(0, &cpu_set);
18	err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
19	ASSERT_OK(err, "set_thread_affinity");
20
21	/* spin the loop for a while (random high number) */
22	for (i = 0; i < 1000000; ++i)
23		++j;
24}
25
26/* TODO: often fails in concurrent mode */
27void serial_test_perf_link(void)
28{
29	struct test_perf_link *skel = NULL;
30	struct perf_event_attr attr;
31	int pfd = -1, link_fd = -1, err;
32	int run_cnt_before, run_cnt_after;
33	struct bpf_link_info info;
34	__u32 info_len = sizeof(info);
35
36	/* create perf event */
37	memset(&attr, 0, sizeof(attr));
38	attr.size = sizeof(attr);
39	attr.type = PERF_TYPE_SOFTWARE;
40	attr.config = PERF_COUNT_SW_CPU_CLOCK;
41	attr.freq = 1;
42	attr.sample_freq = 1000;
43	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
44	if (!ASSERT_GE(pfd, 0, "perf_fd"))
45		goto cleanup;
46
47	skel = test_perf_link__open_and_load();
48	if (!ASSERT_OK_PTR(skel, "skel_load"))
49		goto cleanup;
50
51	link_fd = bpf_link_create(bpf_program__fd(skel->progs.handler), pfd,
52				  BPF_PERF_EVENT, NULL);
53	if (!ASSERT_GE(link_fd, 0, "link_fd"))
54		goto cleanup;
55
56	memset(&info, 0, sizeof(info));
57	err = bpf_link_get_info_by_fd(link_fd, &info, &info_len);
58	if (!ASSERT_OK(err, "link_get_info"))
59		goto cleanup;
60
61	ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "link_type");
62	ASSERT_GT(info.id, 0, "link_id");
63	ASSERT_GT(info.prog_id, 0, "link_prog_id");
64
65	/* ensure we get at least one perf_event prog execution */
66	burn_cpu();
67	ASSERT_GT(skel->bss->run_cnt, 0, "run_cnt");
68
69	/* perf_event is still active, but we close link and BPF program
70	 * shouldn't be executed anymore
71	 */
72	close(link_fd);
73	link_fd = -1;
74
75	/* make sure there are no stragglers */
76	kern_sync_rcu();
77
78	run_cnt_before = skel->bss->run_cnt;
79	burn_cpu();
80	run_cnt_after = skel->bss->run_cnt;
81
82	ASSERT_EQ(run_cnt_before, run_cnt_after, "run_cnt_before_after");
83
84cleanup:
85	if (link_fd >= 0)
86		close(link_fd);
87	if (pfd >= 0)
88		close(pfd);
89	test_perf_link__destroy(skel);
90}
91