tools/perf/tests/backward-ring-buffer.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Test backward bit in event attribute, read ring buffer from end to
   4  * beginning
   5  */
   6
   7 #include <perf.h>
   8 #include <evlist.h>
   9 #include <sys/prctl.h>
  10 #include "tests.h"
  11 #include "debug.h"
  12 #include <errno.h>
  13
  14 #define NR_ITERS 111
  15
  16 static void testcase(void)
  17 {
  18         int i;
  19
  20         for (i = 0; i < NR_ITERS; i++) {
  21                 char proc_name[10];
  22
  23                 snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);
  24                 prctl(PR_SET_NAME, proc_name);
  25         }
  26 }
  27
  28 static int count_samples(struct perf_evlist *evlist, int *sample_count,
  29                          int *comm_count)
  30 {
  31         int i;
  32
  33         for (i = 0; i < evlist->nr_mmaps; i++) {
  34                 struct perf_mmap *map = &evlist->overwrite_mmap[i];
  35                 union perf_event *event;
  36
  37                 perf_mmap__read_init(map);
  38                 while ((event = perf_mmap__read_event(map)) != NULL) {
  39                         const u32 type = event->header.type;
  40
  41                         switch (type) {
  42                         case PERF_RECORD_SAMPLE:
  43                                 (*sample_count)++;
  44                                 break;
  45                         case PERF_RECORD_COMM:
  46                                 (*comm_count)++;
  47                                 break;
  48                         default:
  49                                 pr_err("Unexpected record of type %d\n", type);
  50                                 return TEST_FAIL;
  51                         }
  52                 }
  53                 perf_mmap__read_done(map);
  54         }
  55         return TEST_OK;
  56 }
  57
  58 static int do_test(struct perf_evlist *evlist, int mmap_pages,
  59                    int *sample_count, int *comm_count)
  60 {
  61         int err;
  62         char sbuf[STRERR_BUFSIZE];
  63
  64         err = perf_evlist__mmap(evlist, mmap_pages);
  65         if (err < 0) {
  66                 pr_debug("perf_evlist__mmap: %s\n",
  67                          str_error_r(errno, sbuf, sizeof(sbuf)));
  68                 return TEST_FAIL;
  69         }
  70
  71         perf_evlist__enable(evlist);
  72         testcase();
  73         perf_evlist__disable(evlist);
  74
  75         err = count_samples(evlist, sample_count, comm_count);
  76         perf_evlist__munmap(evlist);
  77         return err;
  78 }
  79
  80
  81 int test__backward_ring_buffer(struct test *test __maybe_unused, int subtest __maybe_unused)
  82 {
  83         int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
  84         char pid[16], sbuf[STRERR_BUFSIZE];
  85         struct perf_evlist *evlist;
  86         struct perf_evsel *evsel __maybe_unused;
  87         struct parse_events_error parse_error;
  88         struct record_opts opts = {
  89                 .target = {
  90                         .uid = UINT_MAX,
  91                         .uses_mmap = true,
  92                 },
  93                 .freq         = 0,
  94                 .mmap_pages   = 256,
  95                 .default_interval = 1,
  96         };
  97
  98         snprintf(pid, sizeof(pid), "%d", getpid());
  99         pid[sizeof(pid) - 1] = '\0';
 100         opts.target.tid = opts.target.pid = pid;
 101
 102         evlist = perf_evlist__new();
 103         if (!evlist) {
 104                 pr_debug("Not enough memory to create evlist\n");
 105                 return TEST_FAIL;
 106         }
 107
 108         err = perf_evlist__create_maps(evlist, &opts.target);
 109         if (err < 0) {
 110                 pr_debug("Not enough memory to create thread/cpu maps\n");
 111                 goto out_delete_evlist;
 112         }
 113
 114         bzero(&parse_error, sizeof(parse_error));
 115         /*
 116          * Set backward bit, ring buffer should be writing from end. Record
 117          * it in aux evlist
 118          */
 119         err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
 120         if (err) {
 121                 pr_debug("Failed to parse tracepoint event, try use root\n");
 122                 ret = TEST_SKIP;
 123                 goto out_delete_evlist;
 124         }
 125
 126         perf_evlist__config(evlist, &opts, NULL);
 127
 128         err = perf_evlist__open(evlist);
 129         if (err < 0) {
 130                 pr_debug("perf_evlist__open: %s\n",
 131                          str_error_r(errno, sbuf, sizeof(sbuf)));
 132                 goto out_delete_evlist;
 133         }
 134
 135         ret = TEST_FAIL;
 136         err = do_test(evlist, opts.mmap_pages, &sample_count,
 137                       &comm_count);
 138         if (err != TEST_OK)
 139                 goto out_delete_evlist;
 140
 141         if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
 142                 pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
 143                        sample_count, comm_count);
 144                 goto out_delete_evlist;
 145         }
 146
 147         err = do_test(evlist, 1, &sample_count, &comm_count);
 148         if (err != TEST_OK)
 149                 goto out_delete_evlist;
 150
 151         ret = TEST_OK;
 152 out_delete_evlist:
 153         perf_evlist__delete(evlist);
 154         return ret;
 155 }