1 // SPDX-License-Identifier: GPL-2.0
5 #include "parse-events.h"
8 #include <subcmd/parse-options.h>
12 typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
14 static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
16 struct perf_evlist *evlist;
17 struct perf_evsel *evsel;
18 unsigned long flags = perf_event_open_cloexec_flag();
19 int err = -EAGAIN, fd;
20 static pid_t pid = -1;
22 evlist = perf_evlist__new();
26 if (parse_events(evlist, str, NULL))
29 evsel = perf_evlist__first(evlist);
32 fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
34 if (pid == -1 && errno == EACCES) {
46 fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
56 perf_evlist__delete(evlist);
60 static bool perf_probe_api(setup_probe_fn_t fn)
62 const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};
66 cpus = cpu_map__new(NULL);
73 ret = perf_do_probe_api(fn, cpu, try[i++]);
76 } while (ret == -EAGAIN && try[i]);
81 static void perf_probe_sample_identifier(struct perf_evsel *evsel)
83 evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
86 static void perf_probe_comm_exec(struct perf_evsel *evsel)
88 evsel->attr.comm_exec = 1;
91 static void perf_probe_context_switch(struct perf_evsel *evsel)
93 evsel->attr.context_switch = 1;
96 bool perf_can_sample_identifier(void)
98 return perf_probe_api(perf_probe_sample_identifier);
101 static bool perf_can_comm_exec(void)
103 return perf_probe_api(perf_probe_comm_exec);
106 bool perf_can_record_switch_events(void)
108 return perf_probe_api(perf_probe_context_switch);
111 bool perf_can_record_cpu_wide(void)
113 struct perf_event_attr attr = {
114 .type = PERF_TYPE_SOFTWARE,
115 .config = PERF_COUNT_SW_CPU_CLOCK,
118 struct cpu_map *cpus;
121 cpus = cpu_map__new(NULL);
127 fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
135 void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
136 struct callchain_param *callchain)
138 struct perf_evsel *evsel;
139 bool use_sample_identifier = false;
141 bool sample_id = opts->sample_id;
144 * Set the evsel leader links before we configure attributes,
145 * since some might depend on this info.
148 perf_evlist__set_leader(evlist);
150 if (evlist->cpus->map[0] < 0)
151 opts->no_inherit = true;
153 use_comm_exec = perf_can_comm_exec();
155 evlist__for_each_entry(evlist, evsel) {
156 perf_evsel__config(evsel, opts, callchain);
157 if (evsel->tracking && use_comm_exec)
158 evsel->attr.comm_exec = 1;
161 if (opts->full_auxtrace) {
163 * Need to be able to synthesize and parse selected events with
164 * arbitrary sample types, which requires always being able to
167 use_sample_identifier = perf_can_sample_identifier();
169 } else if (evlist->nr_entries > 1) {
170 struct perf_evsel *first = perf_evlist__first(evlist);
172 evlist__for_each_entry(evlist, evsel) {
173 if (evsel->attr.sample_type == first->attr.sample_type)
175 use_sample_identifier = perf_can_sample_identifier();
182 evlist__for_each_entry(evlist, evsel)
183 perf_evsel__set_sample_id(evsel, use_sample_identifier);
186 perf_evlist__set_id_pos(evlist);
189 static int get_max_rate(unsigned int *rate)
191 return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
194 static int record_opts__config_freq(struct record_opts *opts)
196 bool user_freq = opts->user_freq != UINT_MAX;
197 unsigned int max_rate;
199 if (opts->user_interval != ULLONG_MAX)
200 opts->default_interval = opts->user_interval;
202 opts->freq = opts->user_freq;
205 * User specified count overrides default frequency.
207 if (opts->default_interval)
209 else if (opts->freq) {
210 opts->default_interval = opts->freq;
212 pr_err("frequency and count are zero, aborting\n");
216 if (get_max_rate(&max_rate))
220 * User specified frequency is over current maximum.
222 if (user_freq && (max_rate < opts->freq)) {
223 if (opts->strict_freq) {
224 pr_err("error: Maximum frequency rate (%'u Hz) exceeded.\n"
225 " Please use -F freq option with a lower value or consider\n"
226 " tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
230 pr_warning("warning: Maximum frequency rate (%'u Hz) exceeded, throttling from %'u Hz to %'u Hz.\n"
231 " The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate.\n"
232 " The kernel will lower it when perf's interrupts take too long.\n"
233 " Use --strict-freq to disable this throttling, refusing to record.\n",
234 max_rate, opts->freq, max_rate);
236 opts->freq = max_rate;
241 * Default frequency is over current maximum.
243 if (max_rate < opts->freq) {
244 pr_warning("Lowering default frequency rate to %u.\n"
245 "Please consider tweaking "
246 "/proc/sys/kernel/perf_event_max_sample_rate.\n",
248 opts->freq = max_rate;
254 int record_opts__config(struct record_opts *opts)
256 return record_opts__config_freq(opts);
259 bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str)
261 struct perf_evlist *temp_evlist;
262 struct perf_evsel *evsel;
267 temp_evlist = perf_evlist__new();
271 err = parse_events(temp_evlist, str, NULL);
275 evsel = perf_evlist__last(temp_evlist);
277 if (!evlist || cpu_map__empty(evlist->cpus)) {
278 struct cpu_map *cpus = cpu_map__new(NULL);
280 cpu = cpus ? cpus->map[0] : 0;
283 cpu = evlist->cpus->map[0];
287 fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1,
288 perf_event_open_cloexec_flag());
290 if (pid == -1 && errno == EACCES) {
302 perf_evlist__delete(temp_evlist);
306 int record__parse_freq(const struct option *opt, const char *str, int unset __maybe_unused)
309 struct record_opts *opts = opt->value;
314 if (strcasecmp(str, "max") == 0) {
315 if (get_max_rate(&freq)) {
316 pr_err("couldn't read /proc/sys/kernel/perf_event_max_sample_rate\n");
319 pr_info("info: Using a maximum frequency rate of %'d Hz\n", freq);
324 opts->user_freq = freq;