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
  8typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
  9
 10static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
 11{
 12	struct perf_evlist *evlist;
 13	struct perf_evsel *evsel;
 14	int err = -EAGAIN, fd;
 15
 16	evlist = perf_evlist__new();
 17	if (!evlist)
 18		return -ENOMEM;
 19
 20	if (parse_events(evlist, str))
 21		goto out_delete;
 22
 23	evsel = perf_evlist__first(evlist);
 24
 25	fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, 0);
 26	if (fd < 0)
 27		goto out_delete;
 28	close(fd);
 29
 30	fn(evsel);
 31
 32	fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, 0);
 33	if (fd < 0) {
 34		if (errno == EINVAL)
 35			err = -EINVAL;
 36		goto out_delete;
 37	}
 38	close(fd);
 39	err = 0;
 40
 41out_delete:
 42	perf_evlist__delete(evlist);
 43	return err;
 44}
 45
 46static bool perf_probe_api(setup_probe_fn_t fn)
 47{
 48	const char *try[] = {"cycles:u", "instructions:u", "cpu-clock", NULL};
 49	struct cpu_map *cpus;
 50	int cpu, ret, i = 0;
 51
 52	cpus = cpu_map__new(NULL);
 53	if (!cpus)
 54		return false;
 55	cpu = cpus->map[0];
 56	cpu_map__delete(cpus);
 57
 58	do {
 59		ret = perf_do_probe_api(fn, cpu, try[i++]);
 60		if (!ret)
 61			return true;
 62	} while (ret == -EAGAIN && try[i]);
 63
 64	return false;
 65}
 66
 67static void perf_probe_sample_identifier(struct perf_evsel *evsel)
 68{
 69	evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
 70}
 71
 72bool perf_can_sample_identifier(void)
 73{
 74	return perf_probe_api(perf_probe_sample_identifier);
 75}
 76
 77void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
 78{
 79	struct perf_evsel *evsel;
 80	bool use_sample_identifier = false;
 81
 82	/*
 83	 * Set the evsel leader links before we configure attributes,
 84	 * since some might depend on this info.
 85	 */
 86	if (opts->group)
 87		perf_evlist__set_leader(evlist);
 88
 89	if (evlist->cpus->map[0] < 0)
 90		opts->no_inherit = true;
 91
 92	evlist__for_each(evlist, evsel)
 93		perf_evsel__config(evsel, opts);
 94
 95	if (evlist->nr_entries > 1) {
 96		struct perf_evsel *first = perf_evlist__first(evlist);
 97
 98		evlist__for_each(evlist, evsel) {
 99			if (evsel->attr.sample_type == first->attr.sample_type)
100				continue;
101			use_sample_identifier = perf_can_sample_identifier();
102			break;
103		}
104		evlist__for_each(evlist, evsel)
105			perf_evsel__set_sample_id(evsel, use_sample_identifier);
106	}
107
108	perf_evlist__set_id_pos(evlist);
109}
110
111static int get_max_rate(unsigned int *rate)
112{
113	char path[PATH_MAX];
114	const char *procfs = procfs__mountpoint();
115
116	if (!procfs)
117		return -1;
118
119	snprintf(path, PATH_MAX,
120		 "%s/sys/kernel/perf_event_max_sample_rate", procfs);
121
122	return filename__read_int(path, (int *) rate);
123}
124
125static int record_opts__config_freq(struct record_opts *opts)
126{
127	bool user_freq = opts->user_freq != UINT_MAX;
128	unsigned int max_rate;
129
130	if (opts->user_interval != ULLONG_MAX)
131		opts->default_interval = opts->user_interval;
132	if (user_freq)
133		opts->freq = opts->user_freq;
134
135	/*
136	 * User specified count overrides default frequency.
137	 */
138	if (opts->default_interval)
139		opts->freq = 0;
140	else if (opts->freq) {
141		opts->default_interval = opts->freq;
142	} else {
143		pr_err("frequency and count are zero, aborting\n");
144		return -1;
145	}
146
147	if (get_max_rate(&max_rate))
148		return 0;
149
150	/*
151	 * User specified frequency is over current maximum.
152	 */
153	if (user_freq && (max_rate < opts->freq)) {
154		pr_err("Maximum frequency rate (%u) reached.\n"
155		   "Please use -F freq option with lower value or consider\n"
156		   "tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
157		   max_rate);
158		return -1;
159	}
160
161	/*
162	 * Default frequency is over current maximum.
163	 */
164	if (max_rate < opts->freq) {
165		pr_warning("Lowering default frequency rate to %u.\n"
166			   "Please consider tweaking "
167			   "/proc/sys/kernel/perf_event_max_sample_rate.\n",
168			   max_rate);
169		opts->freq = max_rate;
170	}
171
172	return 0;
173}
174
175int record_opts__config(struct record_opts *opts)
176{
177	return record_opts__config_freq(opts);
178}
179
180bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str)
181{
182	struct perf_evlist *temp_evlist;
183	struct perf_evsel *evsel;
184	int err, fd, cpu;
185	bool ret = false;
186
187	temp_evlist = perf_evlist__new();
188	if (!temp_evlist)
189		return false;
190
191	err = parse_events(temp_evlist, str);
192	if (err)
193		goto out_delete;
194
195	evsel = perf_evlist__last(temp_evlist);
196
197	if (!evlist || cpu_map__empty(evlist->cpus)) {
198		struct cpu_map *cpus = cpu_map__new(NULL);
199
200		cpu =  cpus ? cpus->map[0] : 0;
201		cpu_map__delete(cpus);
202	} else {
203		cpu = evlist->cpus->map[0];
204	}
205
206	fd = sys_perf_event_open(&evsel->attr, -1, cpu, -1, 0);
207	if (fd >= 0) {
208		close(fd);
209		ret = true;
210	}
211
212out_delete:
213	perf_evlist__delete(temp_evlist);
214	return ret;
215}