tools/perf/tests/mmap-basic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <inttypes.h>
   4 /* For the CLR_() macros */
   5 #include <pthread.h>
   6 #include <stdlib.h>
   7 #include <perf/cpumap.h>
   8
   9 #include "debug.h"
  10 #include "evlist.h"
  11 #include "evsel.h"
  12 #include "thread_map.h"
  13 #include "tests.h"
  14 #include "util/mmap.h"
  15 #include <linux/err.h>
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <perf/evlist.h>
  19 #include <perf/mmap.h>
  20
  21 /*
  22  * This test will generate random numbers of calls to some getpid syscalls,
  23  * then establish an mmap for a group of events that are created to monitor
  24  * the syscalls.
  25  *
  26  * It will receive the events, using mmap, use its PERF_SAMPLE_ID generated
  27  * sample.id field to map back to its respective perf_evsel instance.
  28  *
  29  * Then it checks if the number of syscalls reported as perf events by
  30  * the kernel corresponds to the number of syscalls made.
  31  */
  32 static int test__basic_mmap(struct test *test __maybe_unused, int subtest __maybe_unused)
  33 {
  34         int err = -1;
  35         union perf_event *event;
  36         struct perf_thread_map *threads;
  37         struct perf_cpu_map *cpus;
  38         struct evlist *evlist;
  39         cpu_set_t cpu_set;
  40         const char *syscall_names[] = { "getsid", "getppid", "getpgid", };
  41         pid_t (*syscalls[])(void) = { (void *)getsid, getppid, (void*)getpgid };
  42 #define nsyscalls ARRAY_SIZE(syscall_names)
  43         unsigned int nr_events[nsyscalls],
  44                      expected_nr_events[nsyscalls], i, j;
  45         struct evsel *evsels[nsyscalls], *evsel;
  46         char sbuf[STRERR_BUFSIZE];
  47         struct mmap *md;
  48
  49         threads = thread_map__new(-1, getpid(), UINT_MAX);
  50         if (threads == NULL) {
  51                 pr_debug("thread_map__new\n");
  52                 return -1;
  53         }
  54
  55         cpus = perf_cpu_map__new(NULL);
  56         if (cpus == NULL) {
  57                 pr_debug("perf_cpu_map__new\n");
  58                 goto out_free_threads;
  59         }
  60
  61         CPU_ZERO(&cpu_set);
  62         CPU_SET(cpus->map[0], &cpu_set);
  63         sched_setaffinity(0, sizeof(cpu_set), &cpu_set);
  64         if (sched_setaffinity(0, sizeof(cpu_set), &cpu_set) < 0) {
  65                 pr_debug("sched_setaffinity() failed on CPU %d: %s ",
  66                          cpus->map[0], str_error_r(errno, sbuf, sizeof(sbuf)));
  67                 goto out_free_cpus;
  68         }
  69
  70         evlist = evlist__new();
  71         if (evlist == NULL) {
  72                 pr_debug("evlist__new\n");
  73                 goto out_free_cpus;
  74         }
  75
  76         perf_evlist__set_maps(&evlist->core, cpus, threads);
  77
  78         for (i = 0; i < nsyscalls; ++i) {
  79                 char name[64];
  80
  81                 snprintf(name, sizeof(name), "sys_enter_%s", syscall_names[i]);
  82                 evsels[i] = evsel__newtp("syscalls", name);
  83                 if (IS_ERR(evsels[i])) {
  84                         pr_debug("evsel__new(%s)\n", name);
  85                         goto out_delete_evlist;
  86                 }
  87
  88                 evsels[i]->core.attr.wakeup_events = 1;
  89                 evsel__set_sample_id(evsels[i], false);
  90
  91                 evlist__add(evlist, evsels[i]);
  92
  93                 if (evsel__open(evsels[i], cpus, threads) < 0) {
  94                         pr_debug("failed to open counter: %s, "
  95                                  "tweak /proc/sys/kernel/perf_event_paranoid?\n",
  96                                  str_error_r(errno, sbuf, sizeof(sbuf)));
  97                         goto out_delete_evlist;
  98                 }
  99
 100                 nr_events[i] = 0;
 101                 expected_nr_events[i] = 1 + rand() % 127;
 102         }
 103
 104         if (evlist__mmap(evlist, 128) < 0) {
 105                 pr_debug("failed to mmap events: %d (%s)\n", errno,
 106                          str_error_r(errno, sbuf, sizeof(sbuf)));
 107                 goto out_delete_evlist;
 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         md = &evlist->mmap[0];
 117         if (perf_mmap__read_init(&md->core) < 0)
 118                 goto out_init;
 119
 120         while ((event = perf_mmap__read_event(&md->core)) != NULL) {
 121                 struct perf_sample sample;
 122
 123                 if (event->header.type != PERF_RECORD_SAMPLE) {
 124                         pr_debug("unexpected %s event\n",
 125                                  perf_event__name(event->header.type));
 126                         goto out_delete_evlist;
 127                 }
 128
 129                 err = evlist__parse_sample(evlist, event, &sample);
 130                 if (err) {
 131                         pr_err("Can't parse sample, err = %d\n", err);
 132                         goto out_delete_evlist;
 133                 }
 134
 135                 err = -1;
 136                 evsel = evlist__id2evsel(evlist, sample.id);
 137                 if (evsel == NULL) {
 138                         pr_debug("event with id %" PRIu64
 139                                  " doesn't map to an evsel\n", sample.id);
 140                         goto out_delete_evlist;
 141                 }
 142                 nr_events[evsel->core.idx]++;
 143                 perf_mmap__consume(&md->core);
 144         }
 145         perf_mmap__read_done(&md->core);
 146
 147 out_init:
 148         err = 0;
 149         evlist__for_each_entry(evlist, evsel) {
 150                 if (nr_events[evsel->core.idx] != expected_nr_events[evsel->core.idx]) {
 151                         pr_debug("expected %d %s events, got %d\n",
 152                                  expected_nr_events[evsel->core.idx],
 153                                  evsel__name(evsel), nr_events[evsel->core.idx]);
 154                         err = -1;
 155                         goto out_delete_evlist;
 156                 }
 157         }
 158
 159 out_delete_evlist:
 160         evlist__delete(evlist);
 161 out_free_cpus:
 162         perf_cpu_map__put(cpus);
 163 out_free_threads:
 164         perf_thread_map__put(threads);
 165         return err;
 166 }
 167
 168 DEFINE_SUITE("Read samples using the mmap interface", basic_mmap);