bpf/prog_tests/perf_buffer.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #define _GNU_SOURCE
0003 #include <pthread.h>
0004 #include <sched.h>
0005 #include <sys/socket.h>
0006 #include <test_progs.h>
0007 #include "test_perf_buffer.skel.h"
0008 #include "bpf/libbpf_internal.h"
0009
0010 static int duration;
0011
0012 /* AddressSanitizer sometimes crashes due to data dereference below, due to
0013  * this being mmap()'ed memory. Disable instrumentation with
0014  * no_sanitize_address attribute
0015  */
0016 __attribute__((no_sanitize_address))
0017 static void on_sample(void *ctx, int cpu, void *data, __u32 size)
0018 {
0019     int cpu_data = *(int *)data, duration = 0;
0020     cpu_set_t *cpu_seen = ctx;
0021
0022     if (cpu_data != cpu)
0023         CHECK(cpu_data != cpu, "check_cpu_data",
0024               "cpu_data %d != cpu %d\n", cpu_data, cpu);
0025
0026     CPU_SET(cpu, cpu_seen);
0027 }
0028
0029 int trigger_on_cpu(int cpu)
0030 {
0031     cpu_set_t cpu_set;
0032     int err;
0033
0034     CPU_ZERO(&cpu_set);
0035     CPU_SET(cpu, &cpu_set);
0036
0037     err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
0038     if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n", cpu, err))
0039         return err;
0040
0041     usleep(1);
0042
0043     return 0;
0044 }
0045
0046 void serial_test_perf_buffer(void)
0047 {
0048     int err, on_len, nr_on_cpus = 0, nr_cpus, i, j;
0049     int zero = 0, my_pid = getpid();
0050     struct test_perf_buffer *skel;
0051     cpu_set_t cpu_seen;
0052     struct perf_buffer *pb;
0053     int last_fd = -1, fd;
0054     bool *online;
0055
0056     nr_cpus = libbpf_num_possible_cpus();
0057     if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
0058         return;
0059
0060     err = parse_cpu_mask_file("/sys/devices/system/cpu/online",
0061                   &online, &on_len);
0062     if (CHECK(err, "nr_on_cpus", "err %d\n", err))
0063         return;
0064
0065     for (i = 0; i < on_len; i++)
0066         if (online[i])
0067             nr_on_cpus++;
0068
0069     /* load program */
0070     skel = test_perf_buffer__open_and_load();
0071     if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
0072         goto out_close;
0073
0074     err = bpf_map_update_elem(bpf_map__fd(skel->maps.my_pid_map), &zero, &my_pid, 0);
0075     if (!ASSERT_OK(err, "my_pid_update"))
0076         goto out_close;
0077
0078     /* attach probe */
0079     err = test_perf_buffer__attach(skel);
0080     if (CHECK(err, "attach_kprobe", "err %d\n", err))
0081         goto out_close;
0082
0083     /* set up perf buffer */
0084     pb = perf_buffer__new(bpf_map__fd(skel->maps.perf_buf_map), 1,
0085                   on_sample, NULL, &cpu_seen, NULL);
0086     if (!ASSERT_OK_PTR(pb, "perf_buf__new"))
0087         goto out_close;
0088
0089     CHECK(perf_buffer__epoll_fd(pb) < 0, "epoll_fd",
0090           "bad fd: %d\n", perf_buffer__epoll_fd(pb));
0091
0092     /* trigger kprobe on every CPU */
0093     CPU_ZERO(&cpu_seen);
0094     for (i = 0; i < nr_cpus; i++) {
0095         if (i >= on_len || !online[i]) {
0096             printf("skipping offline CPU #%d\n", i);
0097             continue;
0098         }
0099
0100         if (trigger_on_cpu(i))
0101             goto out_close;
0102     }
0103
0104     /* read perf buffer */
0105     err = perf_buffer__poll(pb, 100);
0106     if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
0107         goto out_free_pb;
0108
0109     if (CHECK(CPU_COUNT(&cpu_seen) != nr_on_cpus, "seen_cpu_cnt",
0110           "expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
0111         goto out_free_pb;
0112
0113     if (CHECK(perf_buffer__buffer_cnt(pb) != nr_on_cpus, "buf_cnt",
0114           "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_on_cpus))
0115         goto out_close;
0116
0117     for (i = 0, j = 0; i < nr_cpus; i++) {
0118         if (i >= on_len || !online[i])
0119             continue;
0120
0121         fd = perf_buffer__buffer_fd(pb, j);
0122         CHECK(fd < 0 || last_fd == fd, "fd_check", "last fd %d == fd %d\n", last_fd, fd);
0123         last_fd = fd;
0124
0125         err = perf_buffer__consume_buffer(pb, j);
0126         if (CHECK(err, "drain_buf", "cpu %d, err %d\n", i, err))
0127             goto out_close;
0128
0129         CPU_CLR(i, &cpu_seen);
0130         if (trigger_on_cpu(i))
0131             goto out_close;
0132
0133         err = perf_buffer__consume_buffer(pb, j);
0134         if (CHECK(err, "consume_buf", "cpu %d, err %d\n", j, err))
0135             goto out_close;
0136
0137         if (CHECK(!CPU_ISSET(i, &cpu_seen), "cpu_seen", "cpu %d not seen\n", i))
0138             goto out_close;
0139         j++;
0140     }
0141
0142 out_free_pb:
0143     perf_buffer__free(pb);
0144 out_close:
0145     test_perf_buffer__destroy(skel);
0146     free(online);
0147 }