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 #include <linux/string.h>
   9
  10 #include "tests.h"
  11 #include "util/debug.h"
  12 #include "util/evsel.h"
  13 #include "util/evlist.h"
  14 #include "util/cpumap.h"
  15 #include "util/mmap.h"
  16 #include "util/thread_map.h"
  17 #include <perf/evlist.h>
  18 #include <perf/mmap.h>
  19
  20 #define NR_LOOPS  10000000
  21
  22 /*
  23  * This test will open software clock events (cpu-clock, task-clock)
  24  * then check their frequency -> period conversion has no artifact of
  25  * setting period to 1 forcefully.
  26  */
  27 static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
  28 {
  29         int i, err = -1;
  30         volatile int tmp = 0;
  31         u64 total_periods = 0;
  32         int nr_samples = 0;
  33         char sbuf[STRERR_BUFSIZE];
  34         union perf_event *event;
  35         struct evsel *evsel;
  36         struct evlist *evlist;
  37         struct perf_event_attr attr = {
  38                 .type = PERF_TYPE_SOFTWARE,
  39                 .config = clock_id,
  40                 .sample_type = PERF_SAMPLE_PERIOD,
  41                 .exclude_kernel = 1,
  42                 .disabled = 1,
  43                 .freq = 1,
  44         };
  45         struct perf_cpu_map *cpus;
  46         struct perf_thread_map *threads;
  47         struct mmap *md;
  48
  49         attr.sample_freq = 500;
  50
  51         evlist = evlist__new();
  52         if (evlist == NULL) {
  53                 pr_debug("evlist__new\n");
  54                 return -1;
  55         }
  56
  57         evsel = evsel__new(&attr);
  58         if (evsel == NULL) {
  59                 pr_debug("evsel__new\n");
  60                 goto out_delete_evlist;
  61         }
  62         evlist__add(evlist, evsel);
  63
  64         cpus = perf_cpu_map__dummy_new();
  65         threads = thread_map__new_by_tid(getpid());
  66         if (!cpus || !threads) {
  67                 err = -ENOMEM;
  68                 pr_debug("Not enough memory to create thread/cpu maps\n");
  69                 goto out_free_maps;
  70         }
  71
  72         perf_evlist__set_maps(&evlist->core, cpus, threads);
  73
  74         cpus    = NULL;
  75         threads = NULL;
  76
  77         if (evlist__open(evlist)) {
  78                 const char *knob = "/proc/sys/kernel/perf_event_max_sample_rate";
  79
  80                 err = -errno;
  81                 pr_debug("Couldn't open evlist: %s\nHint: check %s, using %" PRIu64 " in this test.\n",
  82                          str_error_r(errno, sbuf, sizeof(sbuf)),
  83                          knob, (u64)attr.sample_freq);
  84                 goto out_delete_evlist;
  85         }
  86
  87         err = evlist__mmap(evlist, 128);
  88         if (err < 0) {
  89                 pr_debug("failed to mmap event: %d (%s)\n", errno,
  90                          str_error_r(errno, sbuf, sizeof(sbuf)));
  91                 goto out_delete_evlist;
  92         }
  93
  94         evlist__enable(evlist);
  95
  96         /* collect samples */
  97         for (i = 0; i < NR_LOOPS; i++)
  98                 tmp++;
  99
 100         evlist__disable(evlist);
 101
 102         md = &evlist->mmap[0];
 103         if (perf_mmap__read_init(&md->core) < 0)
 104                 goto out_init;
 105
 106         while ((event = perf_mmap__read_event(&md->core)) != NULL) {
 107                 struct perf_sample sample;
 108
 109                 if (event->header.type != PERF_RECORD_SAMPLE)
 110                         goto next_event;
 111
 112                 err = evlist__parse_sample(evlist, event, &sample);
 113                 if (err < 0) {
 114                         pr_debug("Error during parse sample\n");
 115                         goto out_delete_evlist;
 116                 }
 117
 118                 total_periods += sample.period;
 119                 nr_samples++;
 120 next_event:
 121                 perf_mmap__consume(&md->core);
 122         }
 123         perf_mmap__read_done(&md->core);
 124
 125 out_init:
 126         if ((u64) nr_samples == total_periods) {
 127                 pr_debug("All (%d) samples have period value of 1!\n",
 128                          nr_samples);
 129                 err = -1;
 130         }
 131
 132 out_free_maps:
 133         perf_cpu_map__put(cpus);
 134         perf_thread_map__put(threads);
 135 out_delete_evlist:
 136         evlist__delete(evlist);
 137         return err;
 138 }
 139
 140 int test__sw_clock_freq(struct test *test __maybe_unused, int subtest __maybe_unused)
 141 {
 142         int ret;
 143
 144         ret = __test__sw_clock_freq(PERF_COUNT_SW_CPU_CLOCK);
 145         if (!ret)
 146                 ret = __test__sw_clock_freq(PERF_COUNT_SW_TASK_CLOCK);
 147
 148         return ret;
 149 }