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 #include "map_symbol.h"
  19 #include "mem-events.h"
  20
  21 /*
  22  * evsel__config_leader_sampling() uses special rules for leader sampling.
  23  * However, if the leader is an AUX area event, then assume the event to sample
  24  * is the next event.
  25  */
  26 static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evlist)
  27 {
  28         struct evsel *leader = evsel->leader;
  29
  30         if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader) ||
  31             is_mem_loads_aux_event(leader)) {
  32                 evlist__for_each_entry(evlist, evsel) {
  33                         if (evsel->leader == leader && evsel != evsel->leader)
  34                                 return evsel;
  35                 }
  36         }
  37
  38         return leader;
  39 }
  40
  41 static u64 evsel__config_term_mask(struct evsel *evsel)
  42 {
  43         struct evsel_config_term *term;
  44         struct list_head *config_terms = &evsel->config_terms;
  45         u64 term_types = 0;
  46
  47         list_for_each_entry(term, config_terms, list) {
  48                 term_types |= 1 << term->type;
  49         }
  50         return term_types;
  51 }
  52
  53 static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *evlist)
  54 {
  55         struct perf_event_attr *attr = &evsel->core.attr;
  56         struct evsel *leader = evsel->leader;
  57         struct evsel *read_sampler;
  58         u64 term_types, freq_mask;
  59
  60         if (!leader->sample_read)
  61                 return;
  62
  63         read_sampler = evsel__read_sampler(evsel, evlist);
  64
  65         if (evsel == read_sampler)
  66                 return;
  67
  68         term_types = evsel__config_term_mask(evsel);
  69         /*
  70          * Disable sampling for all group members except those with explicit
  71          * config terms or the leader. In the case of an AUX area event, the 2nd
  72          * event in the group is the one that 'leads' the sampling.
  73          */
  74         freq_mask = (1 << EVSEL__CONFIG_TERM_FREQ) | (1 << EVSEL__CONFIG_TERM_PERIOD);
  75         if ((term_types & freq_mask) == 0) {
  76                 attr->freq           = 0;
  77                 attr->sample_freq    = 0;
  78                 attr->sample_period  = 0;
  79         }
  80         if ((term_types & (1 << EVSEL__CONFIG_TERM_OVERWRITE)) == 0)
  81                 attr->write_backward = 0;
  82
  83         /*
  84          * We don't get a sample for slave events, we make them when delivering
  85          * the group leader sample. Set the slave event to follow the master
  86          * sample_type to ease up reporting.
  87          * An AUX area event also has sample_type requirements, so also include
  88          * the sample type bits from the leader's sample_type to cover that
  89          * case.
  90          */
  91         attr->sample_type = read_sampler->core.attr.sample_type |
  92                             leader->core.attr.sample_type;
  93 }
  94
  95 void evlist__config(struct evlist *evlist, struct record_opts *opts, struct callchain_param *callchain)
  96 {
  97         struct evsel *evsel;
  98         bool use_sample_identifier = false;
  99         bool use_comm_exec;
 100         bool sample_id = opts->sample_id;
 101
 102         /*
 103          * Set the evsel leader links before we configure attributes,
 104          * since some might depend on this info.
 105          */
 106         if (opts->group)
 107                 evlist__set_leader(evlist);
 108
 109         if (evlist->core.cpus->map[0] < 0)
 110                 opts->no_inherit = true;
 111
 112         use_comm_exec = perf_can_comm_exec();
 113
 114         evlist__for_each_entry(evlist, evsel) {
 115                 evsel__config(evsel, opts, callchain);
 116                 if (evsel->tracking && use_comm_exec)
 117                         evsel->core.attr.comm_exec = 1;
 118         }
 119
 120         /* Configure leader sampling here now that the sample type is known */
 121         evlist__for_each_entry(evlist, evsel)
 122                 evsel__config_leader_sampling(evsel, evlist);
 123
 124         if (opts->full_auxtrace) {
 125                 /*
 126                  * Need to be able to synthesize and parse selected events with
 127                  * arbitrary sample types, which requires always being able to
 128                  * match the id.
 129                  */
 130                 use_sample_identifier = perf_can_sample_identifier();
 131                 sample_id = true;
 132         } else if (evlist->core.nr_entries > 1) {
 133                 struct evsel *first = evlist__first(evlist);
 134
 135                 evlist__for_each_entry(evlist, evsel) {
 136                         if (evsel->core.attr.sample_type == first->core.attr.sample_type)
 137                                 continue;
 138                         use_sample_identifier = perf_can_sample_identifier();
 139                         break;
 140                 }
 141                 sample_id = true;
 142         }
 143
 144         if (sample_id) {
 145                 evlist__for_each_entry(evlist, evsel)
 146                         evsel__set_sample_id(evsel, use_sample_identifier);
 147         }
 148
 149         evlist__set_id_pos(evlist);
 150 }
 151
 152 static int get_max_rate(unsigned int *rate)
 153 {
 154         return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
 155 }
 156
 157 static int record_opts__config_freq(struct record_opts *opts)
 158 {
 159         bool user_freq = opts->user_freq != UINT_MAX;
 160         unsigned int max_rate;
 161
 162         if (opts->user_interval != ULLONG_MAX)
 163                 opts->default_interval = opts->user_interval;
 164         if (user_freq)
 165                 opts->freq = opts->user_freq;
 166
 167         /*
 168          * User specified count overrides default frequency.
 169          */
 170         if (opts->default_interval)
 171                 opts->freq = 0;
 172         else if (opts->freq) {
 173                 opts->default_interval = opts->freq;
 174         } else {
 175                 pr_err("frequency and count are zero, aborting\n");
 176                 return -1;
 177         }
 178
 179         if (get_max_rate(&max_rate))
 180                 return 0;
 181
 182         /*
 183          * User specified frequency is over current maximum.
 184          */
 185         if (user_freq && (max_rate < opts->freq)) {
 186                 if (opts->strict_freq) {
 187                         pr_err("error: Maximum frequency rate (%'u Hz) exceeded.\n"
 188                                "       Please use -F freq option with a lower value or consider\n"
 189                                "       tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
 190                                max_rate);
 191                         return -1;
 192                 } else {
 193                         pr_warning("warning: Maximum frequency rate (%'u Hz) exceeded, throttling from %'u Hz to %'u Hz.\n"
 194                                    "         The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate.\n"
 195                                    "         The kernel will lower it when perf's interrupts take too long.\n"
 196                                    "         Use --strict-freq to disable this throttling, refusing to record.\n",
 197                                    max_rate, opts->freq, max_rate);
 198
 199                         opts->freq = max_rate;
 200                 }
 201         }
 202
 203         /*
 204          * Default frequency is over current maximum.
 205          */
 206         if (max_rate < opts->freq) {
 207                 pr_warning("Lowering default frequency rate from %u to %u.\n"
 208                            "Please consider tweaking "
 209                            "/proc/sys/kernel/perf_event_max_sample_rate.\n",
 210                            opts->freq, max_rate);
 211                 opts->freq = max_rate;
 212         }
 213
 214         return 0;
 215 }
 216
 217 int record_opts__config(struct record_opts *opts)
 218 {
 219         return record_opts__config_freq(opts);
 220 }
 221
 222 bool evlist__can_select_event(struct evlist *evlist, const char *str)
 223 {
 224         struct evlist *temp_evlist;
 225         struct evsel *evsel;
 226         int err, fd, cpu;
 227         bool ret = false;
 228         pid_t pid = -1;
 229
 230         temp_evlist = evlist__new();
 231         if (!temp_evlist)
 232                 return false;
 233
 234         err = parse_events(temp_evlist, str, NULL);
 235         if (err)
 236                 goto out_delete;
 237
 238         evsel = evlist__last(temp_evlist);
 239
 240         if (!evlist || perf_cpu_map__empty(evlist->core.cpus)) {
 241                 struct perf_cpu_map *cpus = perf_cpu_map__new(NULL);
 242
 243                 cpu =  cpus ? cpus->map[0] : 0;
 244                 perf_cpu_map__put(cpus);
 245         } else {
 246                 cpu = evlist->core.cpus->map[0];
 247         }
 248
 249         while (1) {
 250                 fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1,
 251                                          perf_event_open_cloexec_flag());
 252                 if (fd < 0) {
 253                         if (pid == -1 && errno == EACCES) {
 254                                 pid = 0;
 255                                 continue;
 256                         }
 257                         goto out_delete;
 258                 }
 259                 break;
 260         }
 261         close(fd);
 262         ret = true;
 263
 264 out_delete:
 265         evlist__delete(temp_evlist);
 266         return ret;
 267 }
 268
 269 int record__parse_freq(const struct option *opt, const char *str, int unset __maybe_unused)
 270 {
 271         unsigned int freq;
 272         struct record_opts *opts = opt->value;
 273
 274         if (!str)
 275                 return -EINVAL;
 276
 277         if (strcasecmp(str, "max") == 0) {
 278                 if (get_max_rate(&freq)) {
 279                         pr_err("couldn't read /proc/sys/kernel/perf_event_max_sample_rate\n");
 280                         return -1;
 281                 }
 282                 pr_info("info: Using a maximum frequency rate of %'d Hz\n", freq);
 283         } else {
 284                 freq = atoi(str);
 285         }
 286
 287         opts->user_freq = freq;
 288         return 0;
 289 }