backward-ring-buffer.c 3.7 KB

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