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 <evlist.h>
   8 #include <sys/prctl.h>
   9 #include "record.h"
  10 #include "tests.h"
  11 #include "debug.h"
  12 #include "parse-events.h"
  13 #include "util/mmap.h"
  14 #include <errno.h>
  15 #include <linux/string.h>
  16 #include <perf/mmap.h>
  17
  18 #define NR_ITERS 111
  19
  20 static void testcase(void)
  21 {
  22         int i;
  23
  24         for (i = 0; i < NR_ITERS; i++) {
  25                 char proc_name[15];
  26
  27                 snprintf(proc_name, sizeof(proc_name), "p:%d\n", i);
  28                 prctl(PR_SET_NAME, proc_name);
  29         }
  30 }
  31
  32 static int count_samples(struct evlist *evlist, int *sample_count,
  33                          int *comm_count)
  34 {
  35         int i;
  36
  37         for (i = 0; i < evlist->core.nr_mmaps; i++) {
  38                 struct mmap *map = &evlist->overwrite_mmap[i];
  39                 union perf_event *event;
  40
  41                 perf_mmap__read_init(&map->core);
  42                 while ((event = perf_mmap__read_event(&map->core)) != NULL) {
  43                         const u32 type = event->header.type;
  44
  45                         switch (type) {
  46                         case PERF_RECORD_SAMPLE:
  47                                 (*sample_count)++;
  48                                 break;
  49                         case PERF_RECORD_COMM:
  50                                 (*comm_count)++;
  51                                 break;
  52                         default:
  53                                 pr_err("Unexpected record of type %d\n", type);
  54                                 return TEST_FAIL;
  55                         }
  56                 }
  57                 perf_mmap__read_done(&map->core);
  58         }
  59         return TEST_OK;
  60 }
  61
  62 static int do_test(struct evlist *evlist, int mmap_pages,
  63                    int *sample_count, int *comm_count)
  64 {
  65         int err;
  66         char sbuf[STRERR_BUFSIZE];
  67
  68         err = evlist__mmap(evlist, mmap_pages);
  69         if (err < 0) {
  70                 pr_debug("evlist__mmap: %s\n",
  71                          str_error_r(errno, sbuf, sizeof(sbuf)));
  72                 return TEST_FAIL;
  73         }
  74
  75         evlist__enable(evlist);
  76         testcase();
  77         evlist__disable(evlist);
  78
  79         err = count_samples(evlist, sample_count, comm_count);
  80         evlist__munmap(evlist);
  81         return err;
  82 }
  83
  84
  85 static int test__backward_ring_buffer(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
  86 {
  87         int ret = TEST_SKIP, err, sample_count = 0, comm_count = 0;
  88         char pid[16], sbuf[STRERR_BUFSIZE];
  89         struct evlist *evlist;
  90         struct evsel *evsel __maybe_unused;
  91         struct parse_events_error parse_error;
  92         struct record_opts opts = {
  93                 .target = {
  94                         .uid = UINT_MAX,
  95                         .uses_mmap = true,
  96                 },
  97                 .freq         = 0,
  98                 .mmap_pages   = 256,
  99                 .default_interval = 1,
 100         };
 101
 102         snprintf(pid, sizeof(pid), "%d", getpid());
 103         pid[sizeof(pid) - 1] = '\0';
 104         opts.target.tid = opts.target.pid = pid;
 105
 106         evlist = evlist__new();
 107         if (!evlist) {
 108                 pr_debug("Not enough memory to create evlist\n");
 109                 return TEST_FAIL;
 110         }
 111
 112         err = evlist__create_maps(evlist, &opts.target);
 113         if (err < 0) {
 114                 pr_debug("Not enough memory to create thread/cpu maps\n");
 115                 goto out_delete_evlist;
 116         }
 117
 118         parse_events_error__init(&parse_error);
 119         /*
 120          * Set backward bit, ring buffer should be writing from end. Record
 121          * it in aux evlist
 122          */
 123         err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
 124         parse_events_error__exit(&parse_error);
 125         if (err) {
 126                 pr_debug("Failed to parse tracepoint event, try use root\n");
 127                 ret = TEST_SKIP;
 128                 goto out_delete_evlist;
 129         }
 130
 131         evlist__config(evlist, &opts, NULL);
 132
 133         err = evlist__open(evlist);
 134         if (err < 0) {
 135                 pr_debug("perf_evlist__open: %s\n",
 136                          str_error_r(errno, sbuf, sizeof(sbuf)));
 137                 goto out_delete_evlist;
 138         }
 139
 140         ret = TEST_FAIL;
 141         err = do_test(evlist, opts.mmap_pages, &sample_count,
 142                       &comm_count);
 143         if (err != TEST_OK)
 144                 goto out_delete_evlist;
 145
 146         if ((sample_count != NR_ITERS) || (comm_count != NR_ITERS)) {
 147                 pr_err("Unexpected counter: sample_count=%d, comm_count=%d\n",
 148                        sample_count, comm_count);
 149                 goto out_delete_evlist;
 150         }
 151
 152         evlist__close(evlist);
 153
 154         err = evlist__open(evlist);
 155         if (err < 0) {
 156                 pr_debug("perf_evlist__open: %s\n",
 157                          str_error_r(errno, sbuf, sizeof(sbuf)));
 158                 goto out_delete_evlist;
 159         }
 160
 161         err = do_test(evlist, 1, &sample_count, &comm_count);
 162         if (err != TEST_OK)
 163                 goto out_delete_evlist;
 164
 165         ret = TEST_OK;
 166 out_delete_evlist:
 167         evlist__delete(evlist);
 168         return ret;
 169 }
 170
 171 DEFINE_SUITE("Read backward ring buffer", backward_ring_buffer);