2 * Test backward bit in event attribute, read ring buffer from end to
14 static void testcase(void)
18 for (i = 0; i < NR_ITERS; i++) {
21 snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);
22 prctl(PR_SET_NAME, proc_name);
26 static int count_samples(struct perf_evlist *evlist, int *sample_count,
31 for (i = 0; i < evlist->nr_mmaps; i++) {
32 union perf_event *event;
34 perf_mmap__read_catchup(&evlist->backward_mmap[i]);
35 while ((event = perf_mmap__read_backward(&evlist->backward_mmap[i])) != NULL) {
36 const u32 type = event->header.type;
39 case PERF_RECORD_SAMPLE:
42 case PERF_RECORD_COMM:
46 pr_err("Unexpected record of type %d\n", type);
54 static int do_test(struct perf_evlist *evlist, int mmap_pages,
55 int *sample_count, int *comm_count)
58 char sbuf[STRERR_BUFSIZE];
60 err = perf_evlist__mmap(evlist, mmap_pages, true);
62 pr_debug("perf_evlist__mmap: %s\n",
63 str_error_r(errno, sbuf, sizeof(sbuf)));
67 perf_evlist__enable(evlist);
69 perf_evlist__disable(evlist);
71 err = count_samples(evlist, sample_count, comm_count);
72 perf_evlist__munmap(evlist);
77 int test__backward_ring_buffer(int subtest __maybe_unused)
79 int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
80 char pid[16], sbuf[STRERR_BUFSIZE];
81 struct perf_evlist *evlist;
82 struct perf_evsel *evsel __maybe_unused;
83 struct parse_events_error parse_error;
84 struct record_opts opts = {
91 .default_interval = 1,
94 snprintf(pid, sizeof(pid), "%d", getpid());
95 pid[sizeof(pid) - 1] = '\0';
96 opts.target.tid = opts.target.pid = pid;
98 evlist = perf_evlist__new();
100 pr_debug("No enough memory to create evlist\n");
104 err = perf_evlist__create_maps(evlist, &opts.target);
106 pr_debug("Not enough memory to create thread/cpu maps\n");
107 goto out_delete_evlist;
110 bzero(&parse_error, sizeof(parse_error));
112 * Set backward bit, ring buffer should be writing from end. Record
115 err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
117 pr_debug("Failed to parse tracepoint event, try use root\n");
119 goto out_delete_evlist;
122 perf_evlist__config(evlist, &opts, NULL);
124 err = perf_evlist__open(evlist);
126 pr_debug("perf_evlist__open: %s\n",
127 str_error_r(errno, sbuf, sizeof(sbuf)));
128 goto out_delete_evlist;
132 err = do_test(evlist, opts.mmap_pages, &sample_count,
135 goto out_delete_evlist;
137 if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
138 pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
139 sample_count, comm_count);
140 goto out_delete_evlist;
143 err = do_test(evlist, 1, &sample_count, &comm_count);
145 goto out_delete_evlist;
149 perf_evlist__delete(evlist);