tools/perf/tests/sw-clock.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <inttypes.h>
   4 #include <unistd.h>
   5 #include <stdlib.h>
   6 #include <signal.h>
   7 #include <sys/mman.h>
   8
   9 #include "tests.h"
  10 #include "util/evsel.h"
  11 #include "util/evlist.h"
  12 #include "util/cpumap.h"
  13 #include "util/thread_map.h"
  14
  15 #define NR_LOOPS  10000000
  16
  17 /*
  18  * This test will open software clock events (cpu-clock, task-clock)
  19  * then check their frequency -> period conversion has no artifact of
  20  * setting period to 1 forcefully.
  21  */
  22 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
  23 {
  24         int i, err = -1;
  25         volatile int tmp = 0;
  26         u64 total_periods = 0;
  27         int nr_samples = 0;
  28         char sbuf[STRERR_BUFSIZE];
  29         union perf_event *event;
  30         struct perf_evsel *evsel;
  31         struct perf_evlist *evlist;
  32         struct perf_event_attr attr = {
  33                 .type = PERF_TYPE_SOFTWARE,
  34                 .config = clock_id,
  35                 .sample_type = PERF_SAMPLE_PERIOD,
  36                 .exclude_kernel = 1,
  37                 .disabled = 1,
  38                 .freq = 1,
  39         };
  40         struct cpu_map *cpus;
  41         struct thread_map *threads;
  42
  43         attr.sample_freq = 500;
  44
  45         evlist = perf_evlist__new();
  46         if (evlist == NULL) {
  47                 pr_debug("perf_evlist__new\n");
  48                 return -1;
  49         }
  50
  51         evsel = perf_evsel__new(&attr);
  52         if (evsel == NULL) {
  53                 pr_debug("perf_evsel__new\n");
  54                 goto out_delete_evlist;
  55         }
  56         perf_evlist__add(evlist, evsel);
  57
  58         cpus = cpu_map__dummy_new();
  59         threads = thread_map__new_by_tid(getpid());
  60         if (!cpus || !threads) {
  61                 err = -ENOMEM;
  62                 pr_debug("Not enough memory to create thread/cpu maps\n");
  63                 goto out_free_maps;
  64         }
  65
  66         perf_evlist__set_maps(evlist, cpus, threads);
  67
  68         cpus    = NULL;
  69         threads = NULL;
  70
  71         if (perf_evlist__open(evlist)) {
  72                 const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
  73
  74                 err = -errno;
  75                 pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
  76                          str_error_r(errno, sbuf, sizeof(sbuf)),
  77                          knob, (u64)attr.sample_freq);
  78                 goto out_delete_evlist;
  79         }
  80
  81         err = perf_evlist__mmap(evlist, 128);
  82         if (err < 0) {
  83                 pr_debug("failed to mmap event: %d (%s)\n", errno,
  84                          str_error_r(errno, sbuf, sizeof(sbuf)));
  85                 goto out_delete_evlist;
  86         }
  87
  88         perf_evlist__enable(evlist);
  89
  90         /* collect samples */
  91         for (i = 0; i < NR_LOOPS; i++)
  92                 tmp++;
  93
  94         perf_evlist__disable(evlist);
  95
  96         while ((event = perf_evlist__mmap_read(evlist, 0)) != NULL) {
  97                 struct perf_sample sample;
  98
  99                 if (event->header.type != PERF_RECORD_SAMPLE)
 100                         goto next_event;
 101
 102                 err = perf_evlist__parse_sample(evlist, event, &sample);
 103                 if (err < 0) {
 104                         pr_debug("Error during parse sample\n");
 105                         goto out_delete_evlist;
 106                 }
 107
 108                 total_periods += sample.period;
 109                 nr_samples++;
 110 next_event:
 111                 perf_evlist__mmap_consume(evlist, 0);
 112         }
 113
 114         if ((u64) nr_samples == total_periods) {
 115                 pr_debug("All (%d) samples have period value of 1!\n",
 116                          nr_samples);
 117                 err = -1;
 118         }
 119
 120 out_free_maps:
 121         cpu_map__put(cpus);
 122         thread_map__put(threads);
 123 out_delete_evlist:
 124         perf_evlist__delete(evlist);
 125         return err;
 126 }
 127
 128 int test__sw_clock_freq(struct test *test __maybe_unused, int subtest __maybe_unused)
 129 {
 130         int ret;
 131
 132         ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
 133         if (!ret)
 134                 ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
 135
 136         return ret;
 137 }