tools/perf/tests/sw-clock.c

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