tools/perf/util/record.c

   1 #include "evlist.h"
   2 #include "evsel.h"
   3 #include "cpumap.h"
   4 #include "parse-events.h"
   5 #include <api/fs/fs.h>
   6 #include "util.h"
   7 #include "cloexec.h"
   8
   9 typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
  10
  11 static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
  12 {
  13         struct perf_evlist *evlist;
  14         struct perf_evsel *evsel;
  15         unsigned long flags = perf_event_open_cloexec_flag();
  16         int err = -EAGAIN, fd;
  17         static pid_t pid = -1;
  18
  19         evlist = perf_evlist__new();
  20         if (!evlist)
  21                 return -ENOMEM;
  22
  23         if (parse_events(evlist, str))
  24                 goto out_delete;
  25
  26         evsel = perf_evlist__first(evlist);
  27
  28         while (1) {
  29                 fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
  30                 if (fd < 0) {
  31                         if (pid == -1 && errno == EACCES) {
  32                                 pid = 0;
  33                                 continue;
  34                         }
  35                         goto out_delete;
  36                 }
  37                 break;
  38         }
  39         close(fd);
  40
  41         fn(evsel);
  42
  43         fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
  44         if (fd < 0) {
  45                 if (errno == EINVAL)
  46                         err = -EINVAL;
  47                 goto out_delete;
  48         }
  49         close(fd);
  50         err = 0;
  51
  52 out_delete:
  53         perf_evlist__delete(evlist);
  54         return err;
  55 }
  56
  57 static bool perf_probe_api(setup_probe_fn_t fn)
  58 {
  59         const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};
  60         struct cpu_map *cpus;
  61         int cpu, ret, i = 0;
  62
  63         cpus = cpu_map__new(NULL);
  64         if (!cpus)
  65                 return false;
  66         cpu = cpus->map[0];
  67         cpu_map__delete(cpus);
  68
  69         do {
  70                 ret = perf_do_probe_api(fn, cpu, try[i++]);
  71                 if (!ret)
  72                         return true;
  73         } while (ret == -EAGAIN && try[i]);
  74
  75         return false;
  76 }
  77
  78 static void perf_probe_sample_identifier(struct perf_evsel *evsel)
  79 {
  80         evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
  81 }
  82
  83 static void perf_probe_comm_exec(struct perf_evsel *evsel)
  84 {
  85         evsel->attr.comm_exec = 1;
  86 }
  87
  88 bool perf_can_sample_identifier(void)
  89 {
  90         return perf_probe_api(perf_probe_sample_identifier);
  91 }
  92
  93 static bool perf_can_comm_exec(void)
  94 {
  95         return perf_probe_api(perf_probe_comm_exec);
  96 }
  97
  98 void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
  99 {
 100         struct perf_evsel *evsel;
 101         bool use_sample_identifier = false;
 102         bool use_comm_exec;
 103
 104         /*
 105          * Set the evsel leader links before we configure attributes,
 106          * since some might depend on this info.
 107          */
 108         if (opts->group)
 109                 perf_evlist__set_leader(evlist);
 110
 111         if (evlist->cpus->map[0] < 0)
 112                 opts->no_inherit = true;
 113
 114         use_comm_exec = perf_can_comm_exec();
 115
 116         evlist__for_each(evlist, evsel) {
 117                 perf_evsel__config(evsel, opts);
 118                 if (evsel->tracking && use_comm_exec)
 119                         evsel->attr.comm_exec = 1;
 120         }
 121
 122         if (evlist->nr_entries > 1) {
 123                 struct perf_evsel *first = perf_evlist__first(evlist);
 124
 125                 evlist__for_each(evlist, evsel) {
 126                         if (evsel->attr.sample_type == first->attr.sample_type)
 127                                 continue;
 128                         use_sample_identifier = perf_can_sample_identifier();
 129                         break;
 130                 }
 131                 evlist__for_each(evlist, evsel)
 132                         perf_evsel__set_sample_id(evsel, use_sample_identifier);
 133         }
 134
 135         perf_evlist__set_id_pos(evlist);
 136 }
 137
 138 static int get_max_rate(unsigned int *rate)
 139 {
 140         char path[PATH_MAX];
 141         const char *procfs = procfs__mountpoint();
 142
 143         if (!procfs)
 144                 return -1;
 145
 146         snprintf(path, PATH_MAX,
 147                  "%s/sys/kernel/perf_event_max_sample_rate", procfs);
 148
 149         return filename__read_int(path, (int *) rate);
 150 }
 151
 152 static int record_opts__config_freq(struct record_opts *opts)
 153 {
 154         bool user_freq = opts->user_freq != UINT_MAX;
 155         unsigned int max_rate;
 156
 157         if (opts->user_interval != ULLONG_MAX)
 158                 opts->default_interval = opts->user_interval;
 159         if (user_freq)
 160                 opts->freq = opts->user_freq;
 161
 162         /*
 163          * User specified count overrides default frequency.
 164          */
 165         if (opts->default_interval)
 166                 opts->freq = 0;
 167         else if (opts->freq) {
 168                 opts->default_interval = opts->freq;
 169         } else {
 170                 pr_err("frequency and count are zero, aborting\n");
 171                 return -1;
 172         }
 173
 174         if (get_max_rate(&max_rate))
 175                 return 0;
 176
 177         /*
 178          * User specified frequency is over current maximum.
 179          */
 180         if (user_freq && (max_rate < opts->freq)) {
 181                 pr_err("Maximum frequency rate (%u) reached.\n"
 182                    "Please use -F freq option with lower value or consider\n"
 183                    "tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
 184                    max_rate);
 185                 return -1;
 186         }
 187
 188         /*
 189          * Default frequency is over current maximum.
 190          */
 191         if (max_rate < opts->freq) {
 192                 pr_warning("Lowering default frequency rate to %u.\n"
 193                            "Please consider tweaking "
 194                            "/proc/sys/kernel/perf_event_max_sample_rate.\n",
 195                            max_rate);
 196                 opts->freq = max_rate;
 197         }
 198
 199         return 0;
 200 }
 201
 202 int record_opts__config(struct record_opts *opts)
 203 {
 204         return record_opts__config_freq(opts);
 205 }
 206
 207 bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str)
 208 {
 209         struct perf_evlist *temp_evlist;
 210         struct perf_evsel *evsel;
 211         int err, fd, cpu;
 212         bool ret = false;
 213         pid_t pid = -1;
 214
 215         temp_evlist = perf_evlist__new();
 216         if (!temp_evlist)
 217                 return false;
 218
 219         err = parse_events(temp_evlist, str);
 220         if (err)
 221                 goto out_delete;
 222
 223         evsel = perf_evlist__last(temp_evlist);
 224
 225         if (!evlist || cpu_map__empty(evlist->cpus)) {
 226                 struct cpu_map *cpus = cpu_map__new(NULL);
 227
 228                 cpu =  cpus ? cpus->map[0] : 0;
 229                 cpu_map__delete(cpus);
 230         } else {
 231                 cpu = evlist->cpus->map[0];
 232         }
 233
 234         while (1) {
 235                 fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1,
 236                                          perf_event_open_cloexec_flag());
 237                 if (fd < 0) {
 238                         if (pid == -1 && errno == EACCES) {
 239                                 pid = 0;
 240                                 continue;
 241                         }
 242                         goto out_delete;
 243                 }
 244                 break;
 245         }
 246         close(fd);
 247         ret = true;
 248
 249 out_delete:
 250         perf_evlist__delete(temp_evlist);
 251         return ret;
 252 }