root/tools/perf/tests/sw-clock.c

DEFINITIONS

1. __test__sw_clock_freq
2. test__sw_clock_freq

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