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