perf test: Add test for the evlist mmap routines

#include "util/cache.h"

#include "util/debug.h"

#include "util/evlist.h"

#include "util/parse-options.h"

#include "util/parse-events.h"

#include "util/session.h"

#include "util/symbol.h"

#include "util/thread.h"

#include "util/evsel.h"

#include <sys/types.h>

static int trace_event__id(const char *event_name)

static int trace_event__id(const char *evname)

{

	char *filename;

	int err = -1, fd;

	if (asprintf(&filename,

		     "/sys/kernel/debug/tracing/events/syscalls/%s/id",

		     event_name) < 0)

		     evname) < 0)

		return -1;

	fd = open(filename, O_RDONLY);

	return err;

}

/*

 * This test will generate random numbers of calls to some getpid syscalls,

 * then establish an mmap for a group of events that are created to monitor

 * the syscalls.

 *

 * It will receive the events, using mmap, use its PERF_SAMPLE_ID generated

 * sample.id field to map back to its respective perf_evsel instance.

 *

 * Then it checks if the number of syscalls reported as perf events by

 * the kernel corresponds to the number of syscalls made.

 */

static int test__basic_mmap(void)

{

	int err = -1;

	event_t *event;

	struct thread_map *threads;

	struct perf_session session;

	struct cpu_map *cpus;

	struct perf_evlist *evlist;

	struct perf_event_attr attr = {

		.type		= PERF_TYPE_TRACEPOINT,

		.read_format	= PERF_FORMAT_ID,

		.sample_type	= PERF_SAMPLE_ID,

		.watermark	= 0,

	};

	cpu_set_t cpu_set;

	const char *syscall_names[] = { "getsid", "getppid", "getpgrp",

					"getpgid", };

	pid_t (*syscalls[])(void) = { (void *)getsid, getppid, getpgrp,

				      (void*)getpgid };

#define nsyscalls ARRAY_SIZE(syscall_names)

	int ids[nsyscalls];

	unsigned int nr_events[nsyscalls],

		     expected_nr_events[nsyscalls], i, j;

	struct perf_evsel *evsels[nsyscalls], *evsel;

	for (i = 0; i < nsyscalls; ++i) {

		char name[64];

		snprintf(name, sizeof(name), "sys_enter_%s", syscall_names[i]);

		ids[i] = trace_event__id(name);

		if (ids[i] < 0) {

			pr_debug("Is debugfs mounted on /sys/kernel/debug?\n");

			return -1;

		}

		nr_events[i] = 0;

		expected_nr_events[i] = random() % 257;

	}

	threads = thread_map__new(-1, getpid());

	if (threads == NULL) {

		pr_debug("thread_map__new\n");

		return -1;

	}

	cpus = cpu_map__new(NULL);

	if (threads == NULL) {

		pr_debug("thread_map__new\n");

		goto out_free_threads;

	}

	CPU_ZERO(&cpu_set);

	CPU_SET(cpus->map[0], &cpu_set);

	sched_setaffinity(0, sizeof(cpu_set), &cpu_set);

	if (sched_setaffinity(0, sizeof(cpu_set), &cpu_set) < 0) {

		pr_debug("sched_setaffinity() failed on CPU %d: %s ",

			 cpus->map[0], strerror(errno));

		goto out_free_cpus;

	}

	evlist = perf_evlist__new();

	if (threads == NULL) {

		pr_debug("perf_evlist__new\n");

		goto out_free_cpus;

	}

	/* anonymous union fields, can't be initialized above */

	attr.wakeup_events = 1;

	attr.sample_period = 1;

	/*

 	 * FIXME: use evsel->attr.sample_type in event__parse_sample.

 	 * 	  This will nicely remove the requirement that we have

 	 * 	  all the events with the same sample_type.

 	 */

	session.sample_type = attr.sample_type;

	for (i = 0; i < nsyscalls; ++i) {

		attr.config = ids[i];

		evsels[i] = perf_evsel__new(&attr, i);

		if (evsels[i] == NULL) {

			pr_debug("perf_evsel__new\n");

			goto out_free_evlist;

		}

		perf_evlist__add(evlist, evsels[i]);

		if (perf_evsel__open(evsels[i], cpus, threads, false, false) < 0) {

			pr_debug("failed to open counter: %s, "

				 "tweak /proc/sys/kernel/perf_event_paranoid?\n",

				 strerror(errno));

			goto out_close_fd;

		}

	}

	if (perf_evlist__mmap(evlist, cpus, threads, 128, true) < 0) {

		pr_debug("failed to mmap events: %d (%s)\n", errno,

			 strerror(errno));

		goto out_close_fd;

	}

	for (i = 0; i < nsyscalls; ++i)

		for (j = 0; j < expected_nr_events[i]; ++j) {

			int foo = syscalls[i]();

			++foo;

		}

	while ((event = perf_evlist__read_on_cpu(evlist, 0)) != NULL) {

		struct sample_data sample;

		if (event->header.type != PERF_RECORD_SAMPLE) {

			pr_debug("unexpected %s event\n",

				 event__get_event_name(event->header.type));

			goto out_munmap;

		}

		event__parse_sample(event, &session, &sample);

		evsel = perf_evlist__id2evsel(evlist, sample.id);

		if (evsel == NULL) {

			pr_debug("event with id %" PRIu64

				 " doesn't map to an evsel\n", sample.id);

			goto out_munmap;

		}

		nr_events[evsel->idx]++;

	}

	list_for_each_entry(evsel, &evlist->entries, node) {

		if (nr_events[evsel->idx] != expected_nr_events[evsel->idx]) {

			pr_debug("expected %d %s events, got %d\n",

				 expected_nr_events[evsel->idx],

				 event_name(evsel), nr_events[evsel->idx]);

			goto out_munmap;

		}

	}

	err = 0;

out_munmap:

	perf_evlist__munmap(evlist, 1);

out_close_fd:

	for (i = 0; i < nsyscalls; ++i)

		perf_evsel__close_fd(evsels[i], 1, threads->nr);

out_free_evlist:

	perf_evlist__delete(evlist);

out_free_cpus:

	cpu_map__delete(cpus);

out_free_threads:

	thread_map__delete(threads);

	return err;

#undef nsyscalls

}

static struct test {

	const char *desc;

	int (*func)(void);

		.desc = "detect open syscall event on all cpus",

		.func = test__open_syscall_event_on_all_cpus,

	},

	{

		.desc = "read samples using the mmap interface",

		.func = test__basic_mmap,

	},

	{

		.func = NULL,

	},