libperf: Add counting example

#include <linux/perf_event.h>

#include <perf/evlist.h>

#include <perf/evsel.h>

#include <perf/cpumap.h>

#include <perf/threadmap.h>

#include <perf/mmap.h>

#include <perf/core.h>

#include <perf/event.h>

#include <stdio.h>

#include <unistd.h>

static int libperf_print(enum libperf_print_level level,

                         const char *fmt, va_list ap)

{

	return vfprintf(stderr, fmt, ap);

}

int main(int argc, char **argv)

{

	int count = 100000, err = 0;

	struct perf_evlist *evlist;

	struct perf_evsel *evsel;

	struct perf_thread_map *threads;

	struct perf_counts_values counts;

	struct perf_event_attr attr1 = {

		.type        = PERF_TYPE_SOFTWARE,

		.config      = PERF_COUNT_SW_CPU_CLOCK,

		.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING,

		.disabled    = 1,

	};

	struct perf_event_attr attr2 = {

		.type        = PERF_TYPE_SOFTWARE,

		.config      = PERF_COUNT_SW_TASK_CLOCK,

		.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED|PERF_FORMAT_TOTAL_TIME_RUNNING,

		.disabled    = 1,

	};

	libperf_init(libperf_print);

	threads = perf_thread_map__new_dummy();

	if (!threads) {

		fprintf(stderr, "failed to create threads\n");

		return -1;

	}

	perf_thread_map__set_pid(threads, 0, 0);

	evlist = perf_evlist__new();

	if (!evlist) {

		fprintf(stderr, "failed to create evlist\n");

		goto out_threads;

	}

	evsel = perf_evsel__new(&attr1);

	if (!evsel) {

		fprintf(stderr, "failed to create evsel1\n");

		goto out_evlist;

	}

	perf_evlist__add(evlist, evsel);

	evsel = perf_evsel__new(&attr2);

	if (!evsel) {

		fprintf(stderr, "failed to create evsel2\n");

		goto out_evlist;

	}

	perf_evlist__add(evlist, evsel);

	perf_evlist__set_maps(evlist, NULL, threads);

	err = perf_evlist__open(evlist);

	if (err) {

		fprintf(stderr, "failed to open evsel\n");

		goto out_evlist;

	}

	perf_evlist__enable(evlist);

	while (count--);

	perf_evlist__disable(evlist);

	perf_evlist__for_each_evsel(evlist, evsel) {

		perf_evsel__read(evsel, 0, 0, &counts);

		fprintf(stdout, "count %llu, enabled %llu, run %llu\n",

				counts.val, counts.ena, counts.run);

	}

	perf_evlist__close(evlist);

out_evlist:

	perf_evlist__delete(evlist);

out_threads:

	perf_thread_map__put(threads);

	return err;

}