summaryrefslogtreecommitdiff
path: root/tools/perf/util/record.c
blob: e70c9dd04567be207d81f3f68835cba17429c8df (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
// SPDX-License-Identifier: GPL-2.0
#include "debug.h"
#include "evlist.h"
#include "evsel.h"
#include "evsel_config.h"
#include "parse-events.h"
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <api/fs/fs.h>
#include <subcmd/parse-options.h>
#include <perf/cpumap.h>
#include "cloexec.h"
#include "util/perf_api_probe.h"
#include "record.h"
#include "../perf-sys.h"
#include "topdown.h"

/*
 * evsel__config_leader_sampling() uses special rules for leader sampling.
 * However, if the leader is an AUX area event, then assume the event to sample
 * is the next event.
 */
static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evlist)
{
	struct evsel *leader = evsel->leader;

	if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader)) {
		evlist__for_each_entry(evlist, evsel) {
			if (evsel->leader == leader && evsel != evsel->leader)
				return evsel;
		}
	}

	return leader;
}

static u64 evsel__config_term_mask(struct evsel *evsel)
{
	struct evsel_config_term *term;
	struct list_head *config_terms = &evsel->config_terms;
	u64 term_types = 0;

	list_for_each_entry(term, config_terms, list) {
		term_types |= 1 << term->type;
	}
	return term_types;
}

static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *evlist)
{
	struct perf_event_attr *attr = &evsel->core.attr;
	struct evsel *leader = evsel->leader;
	struct evsel *read_sampler;
	u64 term_types, freq_mask;

	if (!leader->sample_read)
		return;

	read_sampler = evsel__read_sampler(evsel, evlist);

	if (evsel == read_sampler)
		return;

	term_types = evsel__config_term_mask(evsel);
	/*
	 * Disable sampling for all group members except those with explicit
	 * config terms or the leader. In the case of an AUX area event, the 2nd
	 * event in the group is the one that 'leads' the sampling.
	 */
	freq_mask = (1 << EVSEL__CONFIG_TERM_FREQ) | (1 << EVSEL__CONFIG_TERM_PERIOD);
	if ((term_types & freq_mask) == 0) {
		attr->freq           = 0;
		attr->sample_freq    = 0;
		attr->sample_period  = 0;
	}
	if ((term_types & (1 << EVSEL__CONFIG_TERM_OVERWRITE)) == 0)
		attr->write_backward = 0;

	/*
	 * We don't get a sample for slave events, we make them when delivering
	 * the group leader sample. Set the slave event to follow the master
	 * sample_type to ease up reporting.
	 * An AUX area event also has sample_type requirements, so also include
	 * the sample type bits from the leader's sample_type to cover that
	 * case.
	 */
	attr->sample_type = read_sampler->core.attr.sample_type |
			    leader->core.attr.sample_type;
}

void evlist__config(struct evlist *evlist, struct record_opts *opts, struct callchain_param *callchain)
{
	struct evsel *evsel;
	bool use_sample_identifier = false;
	bool use_comm_exec;
	bool sample_id = opts->sample_id;

	/*
	 * Set the evsel leader links before we configure attributes,
	 * since some might depend on this info.
	 */
	if (opts->group)
		evlist__set_leader(evlist);

	if (evlist->core.cpus->map[0] < 0)
		opts->no_inherit = true;

	use_comm_exec = perf_can_comm_exec();

	evlist__for_each_entry(evlist, evsel) {
		evsel__config(evsel, opts, callchain);
		if (evsel->tracking && use_comm_exec)
			evsel->core.attr.comm_exec = 1;
	}

	/* Configure leader sampling here now that the sample type is known */
	evlist__for_each_entry(evlist, evsel)
		evsel__config_leader_sampling(evsel, evlist);

	if (opts->full_auxtrace) {
		/*
		 * Need to be able to synthesize and parse selected events with
		 * arbitrary sample types, which requires always being able to
		 * match the id.
		 */
		use_sample_identifier = perf_can_sample_identifier();
		sample_id = true;
	} else if (evlist->core.nr_entries > 1) {
		struct evsel *first = evlist__first(evlist);

		evlist__for_each_entry(evlist, evsel) {
			if (evsel->core.attr.sample_type == first->core.attr.sample_type)
				continue;
			use_sample_identifier = perf_can_sample_identifier();
			break;
		}
		sample_id = true;
	}

	if (sample_id) {
		evlist__for_each_entry(evlist, evsel)
			evsel__set_sample_id(evsel, use_sample_identifier);
	}

	evlist__set_id_pos(evlist);
}

static int get_max_rate(unsigned int *rate)
{
	return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
}

static int record_opts__config_freq(struct record_opts *opts)
{
	bool user_freq = opts->user_freq != UINT_MAX;
	unsigned int max_rate;

	if (opts->user_interval != ULLONG_MAX)
		opts->default_interval = opts->user_interval;
	if (user_freq)
		opts->freq = opts->user_freq;

	/*
	 * User specified count overrides default frequency.
	 */
	if (opts->default_interval)
		opts->freq = 0;
	else if (opts->freq) {
		opts->default_interval = opts->freq;
	} else {
		pr_err("frequency and count are zero, aborting\n");
		return -1;
	}

	if (get_max_rate(&max_rate))
		return 0;

	/*
	 * User specified frequency is over current maximum.
	 */
	if (user_freq && (max_rate < opts->freq)) {
		if (opts->strict_freq) {
			pr_err("error: Maximum frequency rate (%'u Hz) exceeded.\n"
			       "       Please use -F freq option with a lower value or consider\n"
			       "       tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
			       max_rate);
			return -1;
		} else {
			pr_warning("warning: Maximum frequency rate (%'u Hz) exceeded, throttling from %'u Hz to %'u Hz.\n"
				   "         The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate.\n"
				   "         The kernel will lower it when perf's interrupts take too long.\n"
				   "         Use --strict-freq to disable this throttling, refusing to record.\n",
				   max_rate, opts->freq, max_rate);

			opts->freq = max_rate;
		}
	}

	/*
	 * Default frequency is over current maximum.
	 */
	if (max_rate < opts->freq) {
		pr_warning("Lowering default frequency rate to %u.\n"
			   "Please consider tweaking "
			   "/proc/sys/kernel/perf_event_max_sample_rate.\n",
			   max_rate);
		opts->freq = max_rate;
	}

	return 0;
}

int record_opts__config(struct record_opts *opts)
{
	return record_opts__config_freq(opts);
}

bool evlist__can_select_event(struct evlist *evlist, const char *str)
{
	struct evlist *temp_evlist;
	struct evsel *evsel;
	int err, fd, cpu;
	bool ret = false;
	pid_t pid = -1;

	temp_evlist = evlist__new();
	if (!temp_evlist)
		return false;

	err = parse_events(temp_evlist, str, NULL);
	if (err)
		goto out_delete;

	evsel = evlist__last(temp_evlist);

	if (!evlist || perf_cpu_map__empty(evlist->core.cpus)) {
		struct perf_cpu_map *cpus = perf_cpu_map__new(NULL);

		cpu =  cpus ? cpus->map[0] : 0;
		perf_cpu_map__put(cpus);
	} else {
		cpu = evlist->core.cpus->map[0];
	}

	while (1) {
		fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1,
					 perf_event_open_cloexec_flag());
		if (fd < 0) {
			if (pid == -1 && errno == EACCES) {
				pid = 0;
				continue;
			}
			goto out_delete;
		}
		break;
	}
	close(fd);
	ret = true;

out_delete:
	evlist__delete(temp_evlist);
	return ret;
}

int record__parse_freq(const struct option *opt, const char *str, int unset __maybe_unused)
{
	unsigned int freq;
	struct record_opts *opts = opt->value;

	if (!str)
		return -EINVAL;

	if (strcasecmp(str, "max") == 0) {
		if (get_max_rate(&freq)) {
			pr_err("couldn't read /proc/sys/kernel/perf_event_max_sample_rate\n");
			return -1;
		}
		pr_info("info: Using a maximum frequency rate of %'d Hz\n", freq);
	} else {
		freq = atoi(str);
	}

	opts->user_freq = freq;
	return 0;
}