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
  38         attr.sample_freq = 500;
  39
  40         evlist = perf_evlist__new();
  41         if (evlist == NULL) {
  42                 pr_debug("perf_evlist__new\n");
  43                 return -1;
  44         }
  45
  46         evsel = perf_evsel__new(&attr);
  47         if (evsel == NULL) {
  48                 pr_debug("perf_evsel__new\n");
  49                 goto out_delete_evlist;
  50         }
  51         perf_evlist__add(evlist, evsel);
  52
  53         evlist->cpus = cpu_map__dummy_new();
  54         evlist->threads = thread_map__new_by_tid(getpid());
  55         if (!evlist->cpus || !evlist->threads) {
  56                 err = -ENOMEM;
  57                 pr_debug("Not enough memory to create thread/cpu maps\n");
  58                 goto out_delete_evlist;
  59         }
  60
  61         if (perf_evlist__open(evlist)) {
  62                 const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
  63
  64                 err = -errno;
  65                 pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
  66                          strerror_r(errno, sbuf, sizeof(sbuf)),
  67                          knob, (u64)attr.sample_freq);
  68                 goto out_delete_evlist;
  69         }
  70
  71         err = perf_evlist__mmap(evlist, 128, true);
  72         if (err < 0) {
  73                 pr_debug("failed to mmap event: %d (%s)\n", errno,
  74                          strerror_r(errno, sbuf, sizeof(sbuf)));
  75                 goto out_delete_evlist;
  76         }
  77
  78         perf_evlist__enable(evlist);
  79
  80         /* collect samples */
  81         for (i = 0; i < NR_LOOPS; i++)
  82                 tmp++;
  83
  84         perf_evlist__disable(evlist);
  85
  86         while ((event = perf_evlist__mmap_read(evlist, 0)) != NULL) {
  87                 struct perf_sample sample;
  88
  89                 if (event->header.type != PERF_RECORD_SAMPLE)
  90                         goto next_event;
  91
  92                 err = perf_evlist__parse_sample(evlist, event, &sample);
  93                 if (err < 0) {
  94                         pr_debug("Error during parse sample\n");
  95                         goto out_delete_evlist;
  96                 }
  97
  98                 total_periods += sample.period;
  99                 nr_samples++;
 100 next_event:
 101                 perf_evlist__mmap_consume(evlist, 0);
 102         }
 103
 104         if ((u64) nr_samples == total_periods) {
 105                 pr_debug("All (%d) samples have period value of 1!\n",
 106                          nr_samples);
 107                 err = -1;
 108         }
 109
 110 out_delete_evlist:
 111         perf_evlist__delete(evlist);
 112         return err;
 113 }
 114
 115 int test__sw_clock_freq(void)
 116 {
 117         int ret;
 118
 119         ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
 120         if (!ret)
 121                 ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
 122
 123         return ret;
 124 }