tools/perf/tests/sw-clock.c

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