tools/perf/tests/mmap-basic.c

   1 #include "evlist.h"
   2 #include "evsel.h"
   3 #include "thread_map.h"
   4 #include "cpumap.h"
   5 #include "tests.h"
   6
   7 /*
   8  * This test will generate random numbers of calls to some getpid syscalls,
   9  * then establish an mmap for a group of events that are created to monitor
  10  * the syscalls.
  11  *
  12  * It will receive the events, using mmap, use its PERF_SAMPLE_ID generated
  13  * sample.id field to map back to its respective perf_evsel instance.
  14  *
  15  * Then it checks if the number of syscalls reported as perf events by
  16  * the kernel corresponds to the number of syscalls made.
  17  */
  18 int test__basic_mmap(void)
  19 {
  20         int err = -1;
  21         union perf_event *event;
  22         struct thread_map *threads;
  23         struct cpu_map *cpus;
  24         struct perf_evlist *evlist;
  25         struct perf_event_attr attr = {
  26                 .type           = PERF_TYPE_TRACEPOINT,
  27                 .read_format    = PERF_FORMAT_ID,
  28                 .sample_type    = PERF_SAMPLE_ID,
  29                 .watermark      = 0,
  30         };
  31         cpu_set_t cpu_set;
  32         const char *syscall_names[] = { "getsid", "getppid", "getpgrp",
  33                                         "getpgid", };
  34         pid_t (*syscalls[])(void) = { (void *)getsid, getppid, getpgrp,
  35                                       (void*)getpgid };
  36 #define nsyscalls ARRAY_SIZE(syscall_names)
  37         int ids[nsyscalls];
  38         unsigned int nr_events[nsyscalls],
  39                      expected_nr_events[nsyscalls], i, j;
  40         struct perf_evsel *evsels[nsyscalls], *evsel;
  41
  42         for (i = 0; i < nsyscalls; ++i) {
  43                 char name[64];
  44
  45                 snprintf(name, sizeof(name), "sys_enter_%s", syscall_names[i]);
  46                 ids[i] = trace_event__id(name);
  47                 if (ids[i] < 0) {
  48                         pr_debug("Is debugfs mounted on /sys/kernel/debug?\n");
  49                         return -1;
  50                 }
  51                 nr_events[i] = 0;
  52                 expected_nr_events[i] = random() % 257;
  53         }
  54
  55         threads = thread_map__new(-1, getpid(), UINT_MAX);
  56         if (threads == NULL) {
  57                 pr_debug("thread_map__new\n");
  58                 return -1;
  59         }
  60
  61         cpus = cpu_map__new(NULL);
  62         if (cpus == NULL) {
  63                 pr_debug("cpu_map__new\n");
  64                 goto out_free_threads;
  65         }
  66
  67         CPU_ZERO(&cpu_set);
  68         CPU_SET(cpus->map[0], &cpu_set);
  69         sched_setaffinity(0, sizeof(cpu_set), &cpu_set);
  70         if (sched_setaffinity(0, sizeof(cpu_set), &cpu_set) < 0) {
  71                 pr_debug("sched_setaffinity() failed on CPU %d: %s ",
  72                          cpus->map[0], strerror(errno));
  73                 goto out_free_cpus;
  74         }
  75
  76         evlist = perf_evlist__new(cpus, threads);
  77         if (evlist == NULL) {
  78                 pr_debug("perf_evlist__new\n");
  79                 goto out_free_cpus;
  80         }
  81
  82         /* anonymous union fields, can't be initialized above */
  83         attr.wakeup_events = 1;
  84         attr.sample_period = 1;
  85
  86         for (i = 0; i < nsyscalls; ++i) {
  87                 attr.config = ids[i];
  88                 evsels[i] = perf_evsel__new(&attr, i);
  89                 if (evsels[i] == NULL) {
  90                         pr_debug("perf_evsel__new\n");
  91                         goto out_free_evlist;
  92                 }
  93
  94                 perf_evlist__add(evlist, evsels[i]);
  95
  96                 if (perf_evsel__open(evsels[i], cpus, threads) < 0) {
  97                         pr_debug("failed to open counter: %s, "
  98                                  "tweak /proc/sys/kernel/perf_event_paranoid?\n",
  99                                  strerror(errno));
 100                         goto out_close_fd;
 101                 }
 102         }
 103
 104         if (perf_evlist__mmap(evlist, 128, true) < 0) {
 105                 pr_debug("failed to mmap events: %d (%s)\n", errno,
 106                          strerror(errno));
 107                 goto out_close_fd;
 108         }
 109
 110         for (i = 0; i < nsyscalls; ++i)
 111                 for (j = 0; j < expected_nr_events[i]; ++j) {
 112                         int foo = syscalls[i]();
 113                         ++foo;
 114                 }
 115
 116         while ((event = perf_evlist__mmap_read(evlist, 0)) != NULL) {
 117                 struct perf_sample sample;
 118
 119                 if (event->header.type != PERF_RECORD_SAMPLE) {
 120                         pr_debug("unexpected %s event\n",
 121                                  perf_event__name(event->header.type));
 122                         goto out_munmap;
 123                 }
 124
 125                 err = perf_evlist__parse_sample(evlist, event, &sample);
 126                 if (err) {
 127                         pr_err("Can't parse sample, err = %d\n", err);
 128                         goto out_munmap;
 129                 }
 130
 131                 evsel = perf_evlist__id2evsel(evlist, sample.id);
 132                 if (evsel == NULL) {
 133                         pr_debug("event with id %" PRIu64
 134                                  " doesn't map to an evsel\n", sample.id);
 135                         goto out_munmap;
 136                 }
 137                 nr_events[evsel->idx]++;
 138         }
 139
 140         list_for_each_entry(evsel, &evlist->entries, node) {
 141                 if (nr_events[evsel->idx] != expected_nr_events[evsel->idx]) {
 142                         pr_debug("expected %d %s events, got %d\n",
 143                                  expected_nr_events[evsel->idx],
 144                                  perf_evsel__name(evsel), nr_events[evsel->idx]);
 145                         goto out_munmap;
 146                 }
 147         }
 148
 149         err = 0;
 150 out_munmap:
 151         perf_evlist__munmap(evlist);
 152 out_close_fd:
 153         for (i = 0; i < nsyscalls; ++i)
 154                 perf_evsel__close_fd(evsels[i], 1, threads->nr);
 155 out_free_evlist:
 156         perf_evlist__delete(evlist);
 157 out_free_cpus:
 158         cpu_map__delete(cpus);
 159 out_free_threads:
 160         thread_map__delete(threads);
 161         return err;
 162 }