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 "testing_helpers.h"
  8#include "test_perf_link.skel.h"
  9
 10#define BURN_TIMEOUT_MS 100
 11#define BURN_TIMEOUT_NS BURN_TIMEOUT_MS * 1000000
 12
 13static void burn_cpu(void)
 14{
 15	volatile int j = 0;
 16	cpu_set_t cpu_set;
 17	int i, err;
 18
 19	/* generate some branches on cpu 0 */
 20	CPU_ZERO(&cpu_set);
 21	CPU_SET(0, &cpu_set);
 22	err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
 23	ASSERT_OK(err, "set_thread_affinity");
 24
 25	/* spin the loop for a while (random high number) */
 26	for (i = 0; i < 1000000; ++i)
 27		++j;
 28}
 29
 30/* TODO: often fails in concurrent mode */
 31void serial_test_perf_link(void)
 32{
 33	struct test_perf_link *skel = NULL;
 34	struct perf_event_attr attr;
 35	int pfd = -1, link_fd = -1, err;
 36	int run_cnt_before, run_cnt_after;
 37	struct bpf_link_info info;
 38	__u32 info_len = sizeof(info);
 39	__u64 timeout_time_ns;
 40
 41	/* create perf event */
 42	memset(&attr, 0, sizeof(attr));
 43	attr.size = sizeof(attr);
 44	attr.type = PERF_TYPE_SOFTWARE;
 45	attr.config = PERF_COUNT_SW_CPU_CLOCK;
 46	attr.freq = 1;
 47	attr.sample_freq = 1000;
 48	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
 49	if (!ASSERT_GE(pfd, 0, "perf_fd"))
 50		goto cleanup;
 51
 52	skel = test_perf_link__open_and_load();
 53	if (!ASSERT_OK_PTR(skel, "skel_load"))
 54		goto cleanup;
 55
 56	link_fd = bpf_link_create(bpf_program__fd(skel->progs.handler), pfd,
 57				  BPF_PERF_EVENT, NULL);
 58	if (!ASSERT_GE(link_fd, 0, "link_fd"))
 59		goto cleanup;
 60
 61	memset(&info, 0, sizeof(info));
 62	err = bpf_link_get_info_by_fd(link_fd, &info, &info_len);
 63	if (!ASSERT_OK(err, "link_get_info"))
 64		goto cleanup;
 65
 66	ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "link_type");
 67	ASSERT_GT(info.id, 0, "link_id");
 68	ASSERT_GT(info.prog_id, 0, "link_prog_id");
 69
 70	/* ensure we get at least one perf_event prog execution */
 71	timeout_time_ns = get_time_ns() + BURN_TIMEOUT_NS;
 72	while (true) {
 73		burn_cpu();
 74		if (skel->bss->run_cnt > 0)
 75			break;
 76	        if (!ASSERT_LT(get_time_ns(), timeout_time_ns, "run_cnt_timeout"))
 77			break;
 78	}
 79
 80	/* perf_event is still active, but we close link and BPF program
 81	 * shouldn't be executed anymore
 82	 */
 83	close(link_fd);
 84	link_fd = -1;
 85
 86	/* make sure there are no stragglers */
 87	kern_sync_rcu();
 88
 89	run_cnt_before = skel->bss->run_cnt;
 90	burn_cpu();
 91	run_cnt_after = skel->bss->run_cnt;
 92
 93	ASSERT_EQ(run_cnt_before, run_cnt_after, "run_cnt_before_after");
 94
 95cleanup:
 96	if (link_fd >= 0)
 97		close(link_fd);
 98	if (pfd >= 0)
 99		close(pfd);
100	test_perf_link__destroy(skel);
101}