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(evsel);
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(evsel) == leader && evsel != evsel__leader(evsel))
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(evsel);
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 if (perf_cpu_map__cpu(evlist->core.user_requested_cpus, 0).cpu < 0)
103 opts->no_inherit = true;
104
105 use_comm_exec = perf_can_comm_exec();
106
107 evlist__for_each_entry(evlist, evsel) {
108 evsel__config(evsel, opts, callchain);
109 if (evsel->tracking && use_comm_exec)
110 evsel->core.attr.comm_exec = 1;
111 }
112
113 /* Configure leader sampling here now that the sample type is known */
114 evlist__for_each_entry(evlist, evsel)
115 evsel__config_leader_sampling(evsel, evlist);
116
117 if (opts->full_auxtrace || opts->sample_identifier) {
118 /*
119 * Need to be able to synthesize and parse selected events with
120 * arbitrary sample types, which requires always being able to
121 * match the id.
122 */
123 use_sample_identifier = perf_can_sample_identifier();
124 sample_id = true;
125 } else if (evlist->core.nr_entries > 1) {
126 struct evsel *first = evlist__first(evlist);
127
128 evlist__for_each_entry(evlist, evsel) {
129 if (evsel->core.attr.sample_type == first->core.attr.sample_type)
130 continue;
131 use_sample_identifier = perf_can_sample_identifier();
132 break;
133 }
134 sample_id = true;
135 }
136
137 if (sample_id) {
138 evlist__for_each_entry(evlist, evsel)
139 evsel__set_sample_id(evsel, use_sample_identifier);
140 }
141
142 evlist__set_id_pos(evlist);
143 }
144
145 static int get_max_rate(unsigned int *rate)
146 {
147 return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
148 }
149
150 static int record_opts__config_freq(struct record_opts *opts)
151 {
152 bool user_freq = opts->user_freq != UINT_MAX;
153 bool user_interval = opts->user_interval != ULLONG_MAX;
154 unsigned int max_rate;
155
156 if (user_interval && user_freq) {
157 pr_err("cannot set frequency and period at the same time\n");
158 return -1;
159 }
160
161 if (user_interval)
162 opts->default_interval = opts->user_interval;
163 if (user_freq)
164 opts->freq = opts->user_freq;
165
166 /*
167 * User specified count overrides default frequency.
168 */
169 if (opts->default_interval)
170 opts->freq = 0;
171 else if (opts->freq) {
172 opts->default_interval = opts->freq;
173 } else {
174 pr_err("frequency and count are zero, aborting\n");
175 return -1;
176 }
177
178 if (get_max_rate(&max_rate))
179 return 0;
180
181 /*
182 * User specified frequency is over current maximum.
183 */
184 if (user_freq && (max_rate < opts->freq)) {
185 if (opts->strict_freq) {
186 pr_err("error: Maximum frequency rate (%'u Hz) exceeded.\n"
187 " Please use -F freq option with a lower value or consider\n"
188 " tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
189 max_rate);
190 return -1;
191 } else {
192 pr_warning("warning: Maximum frequency rate (%'u Hz) exceeded, throttling from %'u Hz to %'u Hz.\n"
193 " The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate.\n"
194 " The kernel will lower it when perf's interrupts take too long.\n"
195 " Use --strict-freq to disable this throttling, refusing to record.\n",
196 max_rate, opts->freq, max_rate);
197
198 opts->freq = max_rate;
199 }
200 }
201
202 /*
203 * Default frequency is over current maximum.
204 */
205 if (max_rate < opts->freq) {
206 pr_warning("Lowering default frequency rate from %u to %u.\n"
207 "Please consider tweaking "
208 "/proc/sys/kernel/perf_event_max_sample_rate.\n",
209 opts->freq, max_rate);
210 opts->freq = max_rate;
211 }
212
213 return 0;
214 }
215
216 int record_opts__config(struct record_opts *opts)
217 {
218 return record_opts__config_freq(opts);
219 }
220
221 bool evlist__can_select_event(struct evlist *evlist, const char *str)
222 {
223 struct evlist *temp_evlist;
224 struct evsel *evsel;
225 int err, fd;
226 struct perf_cpu cpu = { .cpu = 0 };
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_event(temp_evlist, str);
235 if (err)
236 goto out_delete;
237
238 evsel = evlist__last(temp_evlist);
239
240 if (!evlist || perf_cpu_map__is_any_cpu_or_is_empty(evlist->core.user_requested_cpus)) {
241 struct perf_cpu_map *cpus = perf_cpu_map__new_online_cpus();
242
243 if (cpus)
244 cpu = perf_cpu_map__cpu(cpus, 0);
245
246 perf_cpu_map__put(cpus);
247 } else {
248 cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, 0);
249 }
250
251 while (1) {
252 fd = sys_perf_event_open(&evsel->core.attr, pid, cpu.cpu, -1,
253 perf_event_open_cloexec_flag());
254 if (fd < 0) {
255 if (pid == -1 && errno == EACCES) {
256 pid = 0;
257 continue;
258 }
259 goto out_delete;
260 }
261 break;
262 }
263 close(fd);
264 ret = true;
265
266 out_delete:
267 evlist__delete(temp_evlist);
268 return ret;
269 }
270
271 int record__parse_freq(const struct option *opt, const char *str, int unset __maybe_unused)
272 {
273 unsigned int freq;
274 struct record_opts *opts = opt->value;
275
276 if (!str)
277 return -EINVAL;
278
279 if (strcasecmp(str, "max") == 0) {
280 if (get_max_rate(&freq)) {
281 pr_err("couldn't read /proc/sys/kernel/perf_event_max_sample_rate\n");
282 return -1;
283 }
284 pr_info("info: Using a maximum frequency rate of %'d Hz\n", freq);
285 } else {
286 freq = atoi(str);
287 }
288
289 opts->user_freq = freq;
290 return 0;
291 }
292
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