tools/perf/util/record.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "debug.h"
   3 #include "evlist.h"
   4 #include "evsel.h"
   5 #include "evsel_config.h"
   6 #include "parse-events.h"
   7 #include <errno.h>
   8 #include <limits.h>
   9 #include <stdlib.h>
  10 #include <api/fs/fs.h>
  11 #include <subcmd/parse-options.h>
  12 #include <perf/cpumap.h>
  13 #include "cloexec.h"
  14 #include "util/perf_api_probe.h"
  15 #include "record.h"
  16 #include "../perf-sys.h"
  17 #include "topdown.h"
  18
  19 /*
  20  * evsel__config_leader_sampling() uses special rules for leader sampling.
  21  * However, if the leader is an AUX area event, then assume the event to sample
  22  * is the next event.
  23  */
  24 static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evlist)
  25 {
  26         struct evsel *leader = evsel->leader;
  27
  28         if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader)) {
  29                 evlist__for_each_entry(evlist, evsel) {
  30                         if (evsel->leader == leader && evsel != evsel->leader)
  31                                 return evsel;
  32                 }
  33         }
  34
  35         return leader;
  36 }
  37
  38 static u64 evsel__config_term_mask(struct evsel *evsel)
  39 {
  40         struct evsel_config_term *term;
  41         struct list_head *config_terms = &evsel->config_terms;
  42         u64 term_types = 0;
  43
  44         list_for_each_entry(term, config_terms, list) {
  45                 term_types |= 1 << term->type;
  46         }
  47         return term_types;
  48 }
  49
  50 static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *evlist)
  51 {
  52         struct perf_event_attr *attr = &evsel->core.attr;
  53         struct evsel *leader = evsel->leader;
  54         struct evsel *read_sampler;
  55         u64 term_types, freq_mask;
  56
  57         if (!leader->sample_read)
  58                 return;
  59
  60         read_sampler = evsel__read_sampler(evsel, evlist);
  61
  62         if (evsel == read_sampler)
  63                 return;
  64
  65         term_types = evsel__config_term_mask(evsel);
  66         /*
  67          * Disable sampling for all group members except those with explicit
  68          * config terms or the leader. In the case of an AUX area event, the 2nd
  69          * event in the group is the one that 'leads' the sampling.
  70          */
  71         freq_mask = (1 << EVSEL__CONFIG_TERM_FREQ) | (1 << EVSEL__CONFIG_TERM_PERIOD);
  72         if ((term_types & freq_mask) == 0) {
  73                 attr->freq           = 0;
  74                 attr->sample_freq    = 0;
  75                 attr->sample_period  = 0;
  76         }
  77         if ((term_types & (1 << EVSEL__CONFIG_TERM_OVERWRITE)) == 0)
  78                 attr->write_backward = 0;
  79
  80         /*
  81          * We don't get a sample for slave events, we make them when delivering
  82          * the group leader sample. Set the slave event to follow the master
  83          * sample_type to ease up reporting.
  84          * An AUX area event also has sample_type requirements, so also include
  85          * the sample type bits from the leader's sample_type to cover that
  86          * case.
  87          */
  88         attr->sample_type = read_sampler->core.attr.sample_type |
  89                             leader->core.attr.sample_type;
  90 }
  91
  92 void evlist__config(struct evlist *evlist, struct record_opts *opts, struct callchain_param *callchain)
  93 {
  94         struct evsel *evsel;
  95         bool use_sample_identifier = false;
  96         bool use_comm_exec;
  97         bool sample_id = opts->sample_id;
  98
  99         /*
 100          * Set the evsel leader links before we configure attributes,
 101          * since some might depend on this info.
 102          */
 103         if (opts->group)
 104                 evlist__set_leader(evlist);
 105
 106         if (evlist->core.cpus->map[0] < 0)
 107                 opts->no_inherit = true;
 108
 109         use_comm_exec = perf_can_comm_exec();
 110
 111         evlist__for_each_entry(evlist, evsel) {
 112                 evsel__config(evsel, opts, callchain);
 113                 if (evsel->tracking && use_comm_exec)
 114                         evsel->core.attr.comm_exec = 1;
 115         }
 116
 117         /* Configure leader sampling here now that the sample type is known */
 118         evlist__for_each_entry(evlist, evsel)
 119                 evsel__config_leader_sampling(evsel, evlist);
 120
 121         if (opts->full_auxtrace) {
 122                 /*
 123                  * Need to be able to synthesize and parse selected events with
 124                  * arbitrary sample types, which requires always being able to
 125                  * match the id.
 126                  */
 127                 use_sample_identifier = perf_can_sample_identifier();
 128                 sample_id = true;
 129         } else if (evlist->core.nr_entries > 1) {
 130                 struct evsel *first = evlist__first(evlist);
 131
 132                 evlist__for_each_entry(evlist, evsel) {
 133                         if (evsel->core.attr.sample_type == first->core.attr.sample_type)
 134                                 continue;
 135                         use_sample_identifier = perf_can_sample_identifier();
 136                         break;
 137                 }
 138                 sample_id = true;
 139         }
 140
 141         if (sample_id) {
 142                 evlist__for_each_entry(evlist, evsel)
 143                         evsel__set_sample_id(evsel, use_sample_identifier);
 144         }
 145
 146         evlist__set_id_pos(evlist);
 147 }
 148
 149 static int get_max_rate(unsigned int *rate)
 150 {
 151         return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
 152 }
 153
 154 static int record_opts__config_freq(struct record_opts *opts)
 155 {
 156         bool user_freq = opts->user_freq != UINT_MAX;
 157         unsigned int max_rate;
 158
 159         if (opts->user_interval != ULLONG_MAX)
 160                 opts->default_interval = opts->user_interval;
 161         if (user_freq)
 162                 opts->freq = opts->user_freq;
 163
 164         /*
 165          * User specified count overrides default frequency.
 166          */
 167         if (opts->default_interval)
 168                 opts->freq = 0;
 169         else if (opts->freq) {
 170                 opts->default_interval = opts->freq;
 171         } else {
 172                 pr_err("frequency and count are zero, aborting\n");
 173                 return -1;
 174         }
 175
 176         if (get_max_rate(&max_rate))
 177                 return 0;
 178
 179         /*
 180          * User specified frequency is over current maximum.
 181          */
 182         if (user_freq && (max_rate < opts->freq)) {
 183                 if (opts->strict_freq) {
 184                         pr_err("error: Maximum frequency rate (%'u Hz) exceeded.\n"
 185                                "       Please use -F freq option with a lower value or consider\n"
 186                                "       tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
 187                                max_rate);
 188                         return -1;
 189                 } else {
 190                         pr_warning("warning: Maximum frequency rate (%'u Hz) exceeded, throttling from %'u Hz to %'u Hz.\n"
 191                                    "         The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate.\n"
 192                                    "         The kernel will lower it when perf's interrupts take too long.\n"
 193                                    "         Use --strict-freq to disable this throttling, refusing to record.\n",
 194                                    max_rate, opts->freq, max_rate);
 195
 196                         opts->freq = max_rate;
 197                 }
 198         }
 199
 200         /*
 201          * Default frequency is over current maximum.
 202          */
 203         if (max_rate < opts->freq) {
 204                 pr_warning("Lowering default frequency rate to %u.\n"
 205                            "Please consider tweaking "
 206                            "/proc/sys/kernel/perf_event_max_sample_rate.\n",
 207                            max_rate);
 208                 opts->freq = max_rate;
 209         }
 210
 211         return 0;
 212 }
 213
 214 int record_opts__config(struct record_opts *opts)
 215 {
 216         return record_opts__config_freq(opts);
 217 }
 218
 219 bool evlist__can_select_event(struct evlist *evlist, const char *str)
 220 {
 221         struct evlist *temp_evlist;
 222         struct evsel *evsel;
 223         int err, fd, cpu;
 224         bool ret = false;
 225         pid_t pid = -1;
 226
 227         temp_evlist = evlist__new();
 228         if (!temp_evlist)
 229                 return false;
 230
 231         err = parse_events(temp_evlist, str, NULL);
 232         if (err)
 233                 goto out_delete;
 234
 235         evsel = evlist__last(temp_evlist);
 236
 237         if (!evlist || perf_cpu_map__empty(evlist->core.cpus)) {
 238                 struct perf_cpu_map *cpus = perf_cpu_map__new(NULL);
 239
 240                 cpu =  cpus ? cpus->map[0] : 0;
 241                 perf_cpu_map__put(cpus);
 242         } else {
 243                 cpu = evlist->core.cpus->map[0];
 244         }
 245
 246         while (1) {
 247                 fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1,
 248                                          perf_event_open_cloexec_flag());
 249                 if (fd < 0) {
 250                         if (pid == -1 && errno == EACCES) {
 251                                 pid = 0;
 252                                 continue;
 253                         }
 254                         goto out_delete;
 255                 }
 256                 break;
 257         }
 258         close(fd);
 259         ret = true;
 260
 261 out_delete:
 262         evlist__delete(temp_evlist);
 263         return ret;
 264 }
 265
 266 int record__parse_freq(const struct option *opt, const char *str, int unset __maybe_unused)
 267 {
 268         unsigned int freq;
 269         struct record_opts *opts = opt->value;
 270
 271         if (!str)
 272                 return -EINVAL;
 273
 274         if (strcasecmp(str, "max") == 0) {
 275                 if (get_max_rate(&freq)) {
 276                         pr_err("couldn't read /proc/sys/kernel/perf_event_max_sample_rate\n");
 277                         return -1;
 278                 }
 279                 pr_info("info: Using a maximum frequency rate of %'d Hz\n", freq);
 280         } else {
 281                 freq = atoi(str);
 282         }
 283
 284         opts->user_freq = freq;
 285         return 0;
 286 }