tools/perf/util/record.c

   1 #include "evlist.h"
   2 #include "evsel.h"
   3 #include "cpumap.h"
   4 #include "parse-events.h"
   5 #include "fs.h"
   6 #include "util.h"
   7
   8 typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
   9
  10 static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
  11 {
  12         struct perf_evlist *evlist;
  13         struct perf_evsel *evsel;
  14         int err = -EAGAIN, fd;
  15
  16         evlist = perf_evlist__new();
  17         if (!evlist)
  18                 return -ENOMEM;
  19
  20         if (parse_events(evlist, str))
  21                 goto out_delete;
  22
  23         evsel = perf_evlist__first(evlist);
  24
  25         fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, 0);
  26         if (fd < 0)
  27                 goto out_delete;
  28         close(fd);
  29
  30         fn(evsel);
  31
  32         fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, 0);
  33         if (fd < 0) {
  34                 if (errno == EINVAL)
  35                         err = -EINVAL;
  36                 goto out_delete;
  37         }
  38         close(fd);
  39         err = 0;
  40
  41 out_delete:
  42         perf_evlist__delete(evlist);
  43         return err;
  44 }
  45
  46 static bool perf_probe_api(setup_probe_fn_t fn)
  47 {
  48         const char *try[] = {"cycles:u", "instructions:u", "cpu-clock", NULL};
  49         struct cpu_map *cpus;
  50         int cpu, ret, i = 0;
  51
  52         cpus = cpu_map__new(NULL);
  53         if (!cpus)
  54                 return false;
  55         cpu = cpus->map[0];
  56         cpu_map__delete(cpus);
  57
  58         do {
  59                 ret = perf_do_probe_api(fn, cpu, try[i++]);
  60                 if (!ret)
  61                         return true;
  62         } while (ret == -EAGAIN && try[i]);
  63
  64         return false;
  65 }
  66
  67 static void perf_probe_sample_identifier(struct perf_evsel *evsel)
  68 {
  69         evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
  70 }
  71
  72 bool perf_can_sample_identifier(void)
  73 {
  74         return perf_probe_api(perf_probe_sample_identifier);
  75 }
  76
  77 void perf_evlist__config(struct perf_evlist *evlist,
  78                         struct perf_record_opts *opts)
  79 {
  80         struct perf_evsel *evsel;
  81         bool use_sample_identifier = false;
  82
  83         /*
  84          * Set the evsel leader links before we configure attributes,
  85          * since some might depend on this info.
  86          */
  87         if (opts->group)
  88                 perf_evlist__set_leader(evlist);
  89
  90         if (evlist->cpus->map[0] < 0)
  91                 opts->no_inherit = true;
  92
  93         list_for_each_entry(evsel, &evlist->entries, node)
  94                 perf_evsel__config(evsel, opts);
  95
  96         if (evlist->nr_entries > 1) {
  97                 struct perf_evsel *first = perf_evlist__first(evlist);
  98
  99                 list_for_each_entry(evsel, &evlist->entries, node) {
 100                         if (evsel->attr.sample_type == first->attr.sample_type)
 101                                 continue;
 102                         use_sample_identifier = perf_can_sample_identifier();
 103                         break;
 104                 }
 105                 list_for_each_entry(evsel, &evlist->entries, node)
 106                         perf_evsel__set_sample_id(evsel, use_sample_identifier);
 107         }
 108
 109         perf_evlist__set_id_pos(evlist);
 110 }
 111
 112 static int get_max_rate(unsigned int *rate)
 113 {
 114         char path[PATH_MAX];
 115         const char *procfs = procfs__mountpoint();
 116
 117         if (!procfs)
 118                 return -1;
 119
 120         snprintf(path, PATH_MAX,
 121                  "%s/sys/kernel/perf_event_max_sample_rate", procfs);
 122
 123         return filename__read_int(path, (int *) rate);
 124 }
 125
 126 static int perf_record_opts__config_freq(struct perf_record_opts *opts)
 127 {
 128         bool user_freq = opts->user_freq != UINT_MAX;
 129         unsigned int max_rate;
 130
 131         if (opts->user_interval != ULLONG_MAX)
 132                 opts->default_interval = opts->user_interval;
 133         if (user_freq)
 134                 opts->freq = opts->user_freq;
 135
 136         /*
 137          * User specified count overrides default frequency.
 138          */
 139         if (opts->default_interval)
 140                 opts->freq = 0;
 141         else if (opts->freq) {
 142                 opts->default_interval = opts->freq;
 143         } else {
 144                 pr_err("frequency and count are zero, aborting\n");
 145                 return -1;
 146         }
 147
 148         if (get_max_rate(&max_rate))
 149                 return 0;
 150
 151         /*
 152          * User specified frequency is over current maximum.
 153          */
 154         if (user_freq && (max_rate < opts->freq)) {
 155                 pr_err("Maximum frequency rate (%u) reached.\n"
 156                    "Please use -F freq option with lower value or consider\n"
 157                    "tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
 158                    max_rate);
 159                 return -1;
 160         }
 161
 162         /*
 163          * Default frequency is over current maximum.
 164          */
 165         if (max_rate < opts->freq) {
 166                 pr_warning("Lowering default frequency rate to %u.\n"
 167                            "Please consider tweaking "
 168                            "/proc/sys/kernel/perf_event_max_sample_rate.\n",
 169                            max_rate);
 170                 opts->freq = max_rate;
 171         }
 172
 173         return 0;
 174 }
 175
 176 int perf_record_opts__config(struct perf_record_opts *opts)
 177 {
 178         return perf_record_opts__config_freq(opts);
 179 }