xref: /openbmc/linux/tools/perf/util/record.c (revision e2f1cf25)
1 #include "evlist.h"
2 #include "evsel.h"
3 #include "cpumap.h"
4 #include "parse-events.h"
5 #include <api/fs/fs.h>
6 #include "util.h"
7 #include "cloexec.h"
8 
9 typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
10 
11 static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
12 {
13 	struct perf_evlist *evlist;
14 	struct perf_evsel *evsel;
15 	unsigned long flags = perf_event_open_cloexec_flag();
16 	int err = -EAGAIN, fd;
17 	static pid_t pid = -1;
18 
19 	evlist = perf_evlist__new();
20 	if (!evlist)
21 		return -ENOMEM;
22 
23 	if (parse_events(evlist, str, NULL))
24 		goto out_delete;
25 
26 	evsel = perf_evlist__first(evlist);
27 
28 	while (1) {
29 		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
30 		if (fd < 0) {
31 			if (pid == -1 && errno == EACCES) {
32 				pid = 0;
33 				continue;
34 			}
35 			goto out_delete;
36 		}
37 		break;
38 	}
39 	close(fd);
40 
41 	fn(evsel);
42 
43 	fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
44 	if (fd < 0) {
45 		if (errno == EINVAL)
46 			err = -EINVAL;
47 		goto out_delete;
48 	}
49 	close(fd);
50 	err = 0;
51 
52 out_delete:
53 	perf_evlist__delete(evlist);
54 	return err;
55 }
56 
57 static bool perf_probe_api(setup_probe_fn_t fn)
58 {
59 	const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};
60 	struct cpu_map *cpus;
61 	int cpu, ret, i = 0;
62 
63 	cpus = cpu_map__new(NULL);
64 	if (!cpus)
65 		return false;
66 	cpu = cpus->map[0];
67 	cpu_map__put(cpus);
68 
69 	do {
70 		ret = perf_do_probe_api(fn, cpu, try[i++]);
71 		if (!ret)
72 			return true;
73 	} while (ret == -EAGAIN && try[i]);
74 
75 	return false;
76 }
77 
78 static void perf_probe_sample_identifier(struct perf_evsel *evsel)
79 {
80 	evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
81 }
82 
83 static void perf_probe_comm_exec(struct perf_evsel *evsel)
84 {
85 	evsel->attr.comm_exec = 1;
86 }
87 
88 bool perf_can_sample_identifier(void)
89 {
90 	return perf_probe_api(perf_probe_sample_identifier);
91 }
92 
93 static bool perf_can_comm_exec(void)
94 {
95 	return perf_probe_api(perf_probe_comm_exec);
96 }
97 
98 void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
99 {
100 	struct perf_evsel *evsel;
101 	bool use_sample_identifier = false;
102 	bool use_comm_exec;
103 
104 	/*
105 	 * Set the evsel leader links before we configure attributes,
106 	 * since some might depend on this info.
107 	 */
108 	if (opts->group)
109 		perf_evlist__set_leader(evlist);
110 
111 	if (evlist->cpus->map[0] < 0)
112 		opts->no_inherit = true;
113 
114 	use_comm_exec = perf_can_comm_exec();
115 
116 	evlist__for_each(evlist, evsel) {
117 		perf_evsel__config(evsel, opts);
118 		if (evsel->tracking && use_comm_exec)
119 			evsel->attr.comm_exec = 1;
120 	}
121 
122 	if (opts->full_auxtrace) {
123 		/*
124 		 * Need to be able to synthesize and parse selected events with
125 		 * arbitrary sample types, which requires always being able to
126 		 * match the id.
127 		 */
128 		use_sample_identifier = perf_can_sample_identifier();
129 		evlist__for_each(evlist, evsel)
130 			perf_evsel__set_sample_id(evsel, use_sample_identifier);
131 	} else if (evlist->nr_entries > 1) {
132 		struct perf_evsel *first = perf_evlist__first(evlist);
133 
134 		evlist__for_each(evlist, evsel) {
135 			if (evsel->attr.sample_type == first->attr.sample_type)
136 				continue;
137 			use_sample_identifier = perf_can_sample_identifier();
138 			break;
139 		}
140 		evlist__for_each(evlist, evsel)
141 			perf_evsel__set_sample_id(evsel, use_sample_identifier);
142 	}
143 
144 	perf_evlist__set_id_pos(evlist);
145 }
146 
147 static int get_max_rate(unsigned int *rate)
148 {
149 	return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
150 }
151 
152 static int record_opts__config_freq(struct record_opts *opts)
153 {
154 	bool user_freq = opts->user_freq != UINT_MAX;
155 	unsigned int max_rate;
156 
157 	if (opts->user_interval != ULLONG_MAX)
158 		opts->default_interval = opts->user_interval;
159 	if (user_freq)
160 		opts->freq = opts->user_freq;
161 
162 	/*
163 	 * User specified count overrides default frequency.
164 	 */
165 	if (opts->default_interval)
166 		opts->freq = 0;
167 	else if (opts->freq) {
168 		opts->default_interval = opts->freq;
169 	} else {
170 		pr_err("frequency and count are zero, aborting\n");
171 		return -1;
172 	}
173 
174 	if (get_max_rate(&max_rate))
175 		return 0;
176 
177 	/*
178 	 * User specified frequency is over current maximum.
179 	 */
180 	if (user_freq && (max_rate < opts->freq)) {
181 		pr_err("Maximum frequency rate (%u) reached.\n"
182 		   "Please use -F freq option with lower value or consider\n"
183 		   "tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
184 		   max_rate);
185 		return -1;
186 	}
187 
188 	/*
189 	 * Default frequency is over current maximum.
190 	 */
191 	if (max_rate < opts->freq) {
192 		pr_warning("Lowering default frequency rate to %u.\n"
193 			   "Please consider tweaking "
194 			   "/proc/sys/kernel/perf_event_max_sample_rate.\n",
195 			   max_rate);
196 		opts->freq = max_rate;
197 	}
198 
199 	return 0;
200 }
201 
202 int record_opts__config(struct record_opts *opts)
203 {
204 	return record_opts__config_freq(opts);
205 }
206 
207 bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str)
208 {
209 	struct perf_evlist *temp_evlist;
210 	struct perf_evsel *evsel;
211 	int err, fd, cpu;
212 	bool ret = false;
213 	pid_t pid = -1;
214 
215 	temp_evlist = perf_evlist__new();
216 	if (!temp_evlist)
217 		return false;
218 
219 	err = parse_events(temp_evlist, str, NULL);
220 	if (err)
221 		goto out_delete;
222 
223 	evsel = perf_evlist__last(temp_evlist);
224 
225 	if (!evlist || cpu_map__empty(evlist->cpus)) {
226 		struct cpu_map *cpus = cpu_map__new(NULL);
227 
228 		cpu =  cpus ? cpus->map[0] : 0;
229 		cpu_map__put(cpus);
230 	} else {
231 		cpu = evlist->cpus->map[0];
232 	}
233 
234 	while (1) {
235 		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1,
236 					 perf_event_open_cloexec_flag());
237 		if (fd < 0) {
238 			if (pid == -1 && errno == EACCES) {
239 				pid = 0;
240 				continue;
241 			}
242 			goto out_delete;
243 		}
244 		break;
245 	}
246 	close(fd);
247 	ret = true;
248 
249 out_delete:
250 	perf_evlist__delete(temp_evlist);
251 	return ret;
252 }
253