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
burn_cpu(void)9 static 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 */
serial_test_perf_link(void)27 void 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
84 cleanup:
85 if (link_fd >= 0)
86 close(link_fd);
87 if (pfd >= 0)
88 close(pfd);
89 test_perf_link__destroy(skel);
90 }
91