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