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
  9typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
 10
 11static 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
 52out_delete:
 53	perf_evlist__delete(evlist);
 54	return err;
 55}
 56
 57static 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
 78static void perf_probe_sample_identifier(struct perf_evsel *evsel)
 79{
 80	evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
 81}
 82
 83static void perf_probe_comm_exec(struct perf_evsel *evsel)
 84{
 85	evsel->attr.comm_exec = 1;
 86}
 87
 88static void perf_probe_context_switch(struct perf_evsel *evsel)
 89{
 90	evsel->attr.context_switch = 1;
 91}
 92
 93bool perf_can_sample_identifier(void)
 94{
 95	return perf_probe_api(perf_probe_sample_identifier);
 96}
 97
 98static bool perf_can_comm_exec(void)
 99{
100	return perf_probe_api(perf_probe_comm_exec);
101}
102
103bool perf_can_record_switch_events(void)
104{
105	return perf_probe_api(perf_probe_context_switch);
106}
107
108bool perf_can_record_cpu_wide(void)
109{
110	struct perf_event_attr attr = {
111		.type = PERF_TYPE_SOFTWARE,
112		.config = PERF_COUNT_SW_CPU_CLOCK,
113		.exclude_kernel = 1,
114	};
115	struct cpu_map *cpus;
116	int cpu, fd;
117
118	cpus = cpu_map__new(NULL);
119	if (!cpus)
120		return false;
121	cpu = cpus->map[0];
122	cpu_map__put(cpus);
123
124	fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
125	if (fd < 0)
126		return false;
127	close(fd);
128
129	return true;
130}
131
132void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
133{
134	struct perf_evsel *evsel;
135	bool use_sample_identifier = false;
136	bool use_comm_exec;
137
138	/*
139	 * Set the evsel leader links before we configure attributes,
140	 * since some might depend on this info.
141	 */
142	if (opts->group)
143		perf_evlist__set_leader(evlist);
144
145	if (evlist->cpus->map[0] < 0)
146		opts->no_inherit = true;
147
148	use_comm_exec = perf_can_comm_exec();
149
150	evlist__for_each(evlist, evsel) {
151		perf_evsel__config(evsel, opts);
152		if (evsel->tracking && use_comm_exec)
153			evsel->attr.comm_exec = 1;
154	}
155
156	if (opts->full_auxtrace) {
157		/*
158		 * Need to be able to synthesize and parse selected events with
159		 * arbitrary sample types, which requires always being able to
160		 * match the id.
161		 */
162		use_sample_identifier = perf_can_sample_identifier();
163		evlist__for_each(evlist, evsel)
164			perf_evsel__set_sample_id(evsel, use_sample_identifier);
165	} else if (evlist->nr_entries > 1) {
166		struct perf_evsel *first = perf_evlist__first(evlist);
167
168		evlist__for_each(evlist, evsel) {
169			if (evsel->attr.sample_type == first->attr.sample_type)
170				continue;
171			use_sample_identifier = perf_can_sample_identifier();
172			break;
173		}
174		evlist__for_each(evlist, evsel)
175			perf_evsel__set_sample_id(evsel, use_sample_identifier);
176	}
177
178	perf_evlist__set_id_pos(evlist);
179}
180
181static int get_max_rate(unsigned int *rate)
182{
183	return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
184}
185
186static int record_opts__config_freq(struct record_opts *opts)
187{
188	bool user_freq = opts->user_freq != UINT_MAX;
189	unsigned int max_rate;
190
191	if (opts->user_interval != ULLONG_MAX)
192		opts->default_interval = opts->user_interval;
193	if (user_freq)
194		opts->freq = opts->user_freq;
195
196	/*
197	 * User specified count overrides default frequency.
198	 */
199	if (opts->default_interval)
200		opts->freq = 0;
201	else if (opts->freq) {
202		opts->default_interval = opts->freq;
203	} else {
204		pr_err("frequency and count are zero, aborting\n");
205		return -1;
206	}
207
208	if (get_max_rate(&max_rate))
209		return 0;
210
211	/*
212	 * User specified frequency is over current maximum.
213	 */
214	if (user_freq && (max_rate < opts->freq)) {
215		pr_err("Maximum frequency rate (%u) reached.\n"
216		   "Please use -F freq option with lower value or consider\n"
217		   "tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
218		   max_rate);
219		return -1;
220	}
221
222	/*
223	 * Default frequency is over current maximum.
224	 */
225	if (max_rate < opts->freq) {
226		pr_warning("Lowering default frequency rate to %u.\n"
227			   "Please consider tweaking "
228			   "/proc/sys/kernel/perf_event_max_sample_rate.\n",
229			   max_rate);
230		opts->freq = max_rate;
231	}
232
233	return 0;
234}
235
236int record_opts__config(struct record_opts *opts)
237{
238	return record_opts__config_freq(opts);
239}
240
241bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str)
242{
243	struct perf_evlist *temp_evlist;
244	struct perf_evsel *evsel;
245	int err, fd, cpu;
246	bool ret = false;
247	pid_t pid = -1;
248
249	temp_evlist = perf_evlist__new();
250	if (!temp_evlist)
251		return false;
252
253	err = parse_events(temp_evlist, str, NULL);
254	if (err)
255		goto out_delete;
256
257	evsel = perf_evlist__last(temp_evlist);
258
259	if (!evlist || cpu_map__empty(evlist->cpus)) {
260		struct cpu_map *cpus = cpu_map__new(NULL);
261
262		cpu =  cpus ? cpus->map[0] : 0;
263		cpu_map__put(cpus);
264	} else {
265		cpu = evlist->cpus->map[0];
266	}
267
268	while (1) {
269		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1,
270					 perf_event_open_cloexec_flag());
271		if (fd < 0) {
272			if (pid == -1 && errno == EACCES) {
273				pid = 0;
274				continue;
275			}
276			goto out_delete;
277		}
278		break;
279	}
280	close(fd);
281	ret = true;
282
283out_delete:
284	perf_evlist__delete(temp_evlist);
285	return ret;
286}