src/evsel.c

#include "ras.h"
#include "cpumap.h"
#include "debug.h"
#include "evsel.h"
#include "xyarray.h"

int __perf_evsel__sample_size(u64 sample_type)
{
	u64 mask = sample_type & PERF_SAMPLE_MASK;
	int size = 0;
	int i;

	for (i = 0; i < 64; i++) {
		if (mask & (1ULL << i))
			size++;
	}

	size *= sizeof(u64);

	return size;
}

/**
 * __perf_evsel__calc_id_pos - calculate id_pos.
 * @sample_type: sample type
 *
 * This function returns the position of the event id (PERF_SAMPLE_ID or
 * PERF_SAMPLE_IDENTIFIER) in a sample event i.e. in the array of struct
 * sample_event.
 */
static int __perf_evsel__calc_id_pos(u64 sample_type)
{
	int idx = 0;

	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		return 0;

	if (!(sample_type & PERF_SAMPLE_ID))
		return -1;

	if (sample_type & PERF_SAMPLE_IP)
		idx += 1;

	if (sample_type & PERF_SAMPLE_TID)
		idx += 1;

	if (sample_type & PERF_SAMPLE_TIME)
		idx += 1;

	if (sample_type & PERF_SAMPLE_ADDR)
		idx += 1;

	return idx;
}

/**
 * __perf_evsel__calc_is_pos - calculate is_pos.
 * @sample_type: sample type
 *
 * This function returns the position (counting backwards) of the event id
 * (PERF_SAMPLE_ID or PERF_SAMPLE_IDENTIFIER) in a non-sample event i.e. if
 * sample_id_all is used there is an id sample appended to non-sample events.
 */
static int __perf_evsel__calc_is_pos(u64 sample_type)
{
	int idx = 1;

	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		return 1;

	if (!(sample_type & PERF_SAMPLE_ID))
		return -1;

	if (sample_type & PERF_SAMPLE_CPU)
		idx += 1;

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		idx += 1;

	return idx;
}

void perf_evsel__calc_id_pos(struct perf_evsel *evsel)
{
	evsel->id_pos = __perf_evsel__calc_id_pos(evsel->attr.sample_type);
	evsel->is_pos = __perf_evsel__calc_is_pos(evsel->attr.sample_type);
}

void perf_evsel__exit(struct perf_evsel *evsel)
{
	assert(list_empty(&evsel->node));
	perf_evsel__free_fd(evsel);
	perf_evsel__free_id(evsel);
}

void perf_evsel__delete(struct perf_evsel *evsel)
{
	perf_evsel__exit(evsel);
/* 	close_cgroup(evsel->cgrp); */
	zfree(&evsel->group_name);
	/*
	if (evsel->tp_format)
		pevent_free_format(evsel->tp_format);
		*/
	zfree(&evsel->name);
	free(evsel);
}

void __perf_evsel__set_sample_bit(struct perf_evsel *evsel,
				  enum perf_event_sample_format bit)
{
	if (!(evsel->attr.sample_type & bit)) {
		evsel->attr.sample_type |= bit;
		evsel->sample_size += sizeof(u64);
		perf_evsel__calc_id_pos(evsel);
	}
}

void __perf_evsel__reset_sample_bit(struct perf_evsel *evsel,
				    enum perf_event_sample_format bit)
{
	if (evsel->attr.sample_type & bit) {
		evsel->attr.sample_type &= ~bit;
		evsel->sample_size -= sizeof(u64);
		perf_evsel__calc_id_pos(evsel);
	}
}

void perf_evsel__set_sample_id(struct perf_evsel *evsel,
			       bool can_sample_identifier)
{
	if (can_sample_identifier) {
		perf_evsel__reset_sample_bit(evsel, ID);
		perf_evsel__set_sample_bit(evsel, IDENTIFIER);
	} else {
		perf_evsel__set_sample_bit(evsel, ID);
	}
	evsel->attr.read_format |= PERF_FORMAT_ID;
}

void perf_evsel__init(struct perf_evsel *evsel,
		      struct perf_event_attr *attr, int idx)
{
	evsel->idx	   = idx;
	evsel->attr	   = *attr;
	evsel->leader	   = evsel;
	evsel->unit	   = "";
	evsel->scale	   = 1.0;
	INIT_LIST_HEAD(&evsel->node);
/* 	hists__init(&evsel->hists); */
	evsel->sample_size = __perf_evsel__sample_size(attr->sample_type);
	perf_evsel__calc_id_pos(evsel);
}

struct perf_evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx)
{
	struct perf_evsel *evsel = zalloc(sizeof(*evsel));

	if (evsel != NULL)
		perf_evsel__init(evsel, attr, idx);

	return evsel;
}

struct perf_evsel *perf_evsel__newtp_idx(const char *sys, const char *name, int idx)
{
	struct perf_evsel *evsel = zalloc(sizeof(*evsel));

	if (evsel != NULL) {
		struct perf_event_attr attr = {
			.type	       = PERF_TYPE_TRACEPOINT,
			.sample_type   = (PERF_SAMPLE_RAW | PERF_SAMPLE_TIME |
					  PERF_SAMPLE_CPU | PERF_SAMPLE_PERIOD),
		};

		if (asprintf(&evsel->name, "%s:%s", sys, name) < 0)
			goto out_free;

		/*
		evsel->tp_format = trace_event__tp_format(sys, name);
		if (evsel->tp_format == NULL)
			goto out_free;
			*/

		event_attr_init(&attr);
		/*
		attr.config = evsel->tp_format->id;
		*/
		attr.sample_period = 1;
		perf_evsel__init(evsel, &attr, idx);
	}

	return evsel;

out_free:
	zfree(&evsel->name);
	free(evsel);
	return NULL;
}

int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads)
{
	evsel->sample_id = xyarray__new(ncpus, nthreads, sizeof(struct perf_sample_id));
	if (evsel->sample_id == NULL)
		return -ENOMEM;

	evsel->id = zalloc(ncpus * nthreads * sizeof(u64));
	if (evsel->id == NULL) {
		xyarray__delete(evsel->sample_id);
		evsel->sample_id = NULL;
		return -ENOMEM;
	}

	return 0;
}

static int perf_evsel__parse_id_sample(const struct perf_evsel *evsel,
				       const union perf_event *event,
				       struct perf_sample *sample)
{
	u64 type = evsel->attr.sample_type;
	const u64 *array = event->sample.array;
	bool swapped = evsel->needs_swap;
	union u64_swap u;

	array += ((event->header.size -
		   sizeof(event->header)) / sizeof(u64)) - 1;

	if (type & PERF_SAMPLE_IDENTIFIER) {
		sample->id = *array;
		array--;
	}

	if (type & PERF_SAMPLE_CPU) {
		u.val64 = *array;
		if (swapped) {
			/* undo swap of u64, then swap on individual u32s */
			u.val64 = bswap_64(u.val64);
			u.val32[0] = bswap_32(u.val32[0]);
		}

		sample->cpu = u.val32[0];
		array--;
	}

	if (type & PERF_SAMPLE_STREAM_ID) {
		sample->stream_id = *array;
		array--;
	}

	if (type & PERF_SAMPLE_ID) {
		sample->id = *array;
		array--;
	}

	if (type & PERF_SAMPLE_TIME) {
		sample->time = *array;
		array--;
	}

	if (type & PERF_SAMPLE_TID) {
		u.val64 = *array;
		if (swapped) {
			/* undo swap of u64, then swap on individual u32s */
			u.val64 = bswap_64(u.val64);
			u.val32[0] = bswap_32(u.val32[0]);
			u.val32[1] = bswap_32(u.val32[1]);
		}

		sample->pid = u.val32[0];
		sample->tid = u.val32[1];
		array--;
	}

	return 0;
}

static inline bool overflow(const void *endp, u16 max_size, const void *offset,
			    u64 size)
{
	return size > max_size || offset + size > endp;
}

#define OVERFLOW_CHECK(offset, size, max_size)				\
	do {								\
		if (overflow(endp, (max_size), (offset), (size)))	\
			return -EFAULT;					\
	} while (0)

#define OVERFLOW_CHECK_u64(offset) \
	OVERFLOW_CHECK(offset, sizeof(u64), sizeof(u64))

int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
			     struct perf_sample *data)
{
	u64 type = evsel->attr.sample_type;
	bool swapped = evsel->needs_swap;
	const u64 *array;
	u16 max_size = event->header.size;
	const void *endp = (void *)event + max_size;
	u64 sz;

	/*
	 * used for cross-endian analysis. See git commit 65014ab3
	 * for why this goofiness is needed.
	 */
	union u64_swap u;

	memset(data, 0, sizeof(*data));
	data->cpu = data->pid = data->tid = -1;
	data->stream_id = data->id = data->time = -1ULL;
	data->period = evsel->attr.sample_period;
	data->weight = 0;

	if (event->header.type != PERF_RECORD_SAMPLE) {
		if (!evsel->attr.sample_id_all)
			return 0;
		return perf_evsel__parse_id_sample(evsel, event, data);
	}

	array = event->sample.array;

	/*
	 * The evsel's sample_size is based on PERF_SAMPLE_MASK which includes
	 * up to PERF_SAMPLE_PERIOD.  After that overflow() must be used to
	 * check the format does not go past the end of the event.
	 */
	if (evsel->sample_size + sizeof(event->header) > event->header.size)
		return -EFAULT;

	data->id = -1ULL;
	if (type & PERF_SAMPLE_IDENTIFIER) {
		data->id = *array;
		array++;
	}

	if (type & PERF_SAMPLE_IP) {
		data->ip = *array;
		array++;
	}

	if (type & PERF_SAMPLE_TID) {
		u.val64 = *array;
		if (swapped) {
			/* undo swap of u64, then swap on individual u32s */
			u.val64 = bswap_64(u.val64);
			u.val32[0] = bswap_32(u.val32[0]);
			u.val32[1] = bswap_32(u.val32[1]);
		}

		data->pid = u.val32[0];
		data->tid = u.val32[1];
		array++;
	}

	if (type & PERF_SAMPLE_TIME) {
		data->time = *array;
		array++;
	}

	data->addr = 0;
	if (type & PERF_SAMPLE_ADDR) {
		data->addr = *array;
		array++;
	}

	if (type & PERF_SAMPLE_ID) {
		data->id = *array;
		array++;
	}

	if (type & PERF_SAMPLE_STREAM_ID) {
		data->stream_id = *array;
		array++;
	}

	if (type & PERF_SAMPLE_CPU) {

		u.val64 = *array;
		if (swapped) {
			/* undo swap of u64, then swap on individual u32s */
			u.val64 = bswap_64(u.val64);
			u.val32[0] = bswap_32(u.val32[0]);
		}

		data->cpu = u.val32[0];
		array++;
	}

	if (type & PERF_SAMPLE_PERIOD) {
		data->period = *array;
		array++;
	}

	if (type & PERF_SAMPLE_READ) {
		u64 read_format = evsel->attr.read_format;

		OVERFLOW_CHECK_u64(array);
		if (read_format & PERF_FORMAT_GROUP)
			data->read.group.nr = *array;
		else
			data->read.one.value = *array;

		array++;

		if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
			OVERFLOW_CHECK_u64(array);
			data->read.time_enabled = *array;
			array++;
		}

		if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
			OVERFLOW_CHECK_u64(array);
			data->read.time_running = *array;
			array++;
		}

		/* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
		if (read_format & PERF_FORMAT_GROUP) {
			const u64 max_group_nr = UINT64_MAX /
					sizeof(struct sample_read_value);

			if (data->read.group.nr > max_group_nr)
				return -EFAULT;
			sz = data->read.group.nr *
			     sizeof(struct sample_read_value);
			OVERFLOW_CHECK(array, sz, max_size);
			data->read.group.values =
					(struct sample_read_value *)array;
			array = (void *)array + sz;
		} else {
			OVERFLOW_CHECK_u64(array);
			data->read.one.id = *array;
			array++;
		}
	}

#if 0
	if (type & PERF_SAMPLE_CALLCHAIN) {
		const u64 max_callchain_nr = UINT64_MAX / sizeof(u64);

		OVERFLOW_CHECK_u64(array);
		data->callchain = (struct ip_callchain *)array++;
		if (data->callchain->nr > max_callchain_nr)
			return -EFAULT;
		sz = data->callchain->nr * sizeof(u64);
		OVERFLOW_CHECK(array, sz, max_size);
		array = (void *)array + sz;
	}
#endif

	if (type & PERF_SAMPLE_RAW) {
		OVERFLOW_CHECK_u64(array);
		u.val64 = *array;
		if (WARN_ONCE(swapped,
			      "Endianness of raw data not corrected!\n")) {
			/* undo swap of u64, then swap on individual u32s */
			u.val64 = bswap_64(u.val64);
			u.val32[0] = bswap_32(u.val32[0]);
			u.val32[1] = bswap_32(u.val32[1]);
		}
		data->raw_size = u.val32[0];
		array = (void *)array + sizeof(u32);

		OVERFLOW_CHECK(array, data->raw_size, max_size);
		data->raw_data = (void *)array;
		array = (void *)array + data->raw_size;
	}

#if 0
	if (type & PERF_SAMPLE_BRANCH_STACK) {
		const u64 max_branch_nr = UINT64_MAX /
					  sizeof(struct branch_entry);

		OVERFLOW_CHECK_u64(array);
		data->branch_stack = (struct branch_stack *)array++;

		if (data->branch_stack->nr > max_branch_nr)
			return -EFAULT;
		sz = data->branch_stack->nr * sizeof(struct branch_entry);
		OVERFLOW_CHECK(array, sz, max_size);
		array = (void *)array + sz;
	}
#endif

	if (type & PERF_SAMPLE_REGS_USER) {
		OVERFLOW_CHECK_u64(array);
		data->user_regs.abi = *array;
		array++;

		if (data->user_regs.abi) {
			u64 mask = evsel->attr.sample_regs_user;

			sz = hweight_long(mask) * sizeof(u64);
			OVERFLOW_CHECK(array, sz, max_size);
			data->user_regs.mask = mask;
			data->user_regs.regs = (u64 *)array;
			array = (void *)array + sz;
		}
	}

	if (type & PERF_SAMPLE_STACK_USER) {
		OVERFLOW_CHECK_u64(array);
		sz = *array++;

		data->user_stack.offset = ((char *)(array - 1)
					  - (char *) event);

		if (!sz) {
			data->user_stack.size = 0;
		} else {
			OVERFLOW_CHECK(array, sz, max_size);
			data->user_stack.data = (char *)array;
			array = (void *)array + sz;
			OVERFLOW_CHECK_u64(array);
			data->user_stack.size = *array++;
			if (WARN_ONCE(data->user_stack.size > sz,
				      "user stack dump failure\n"))
				return -EFAULT;
		}
	}

	data->weight = 0;
	if (type & PERF_SAMPLE_WEIGHT) {
		OVERFLOW_CHECK_u64(array);
		data->weight = *array;
		array++;
	}

	data->data_src = PERF_MEM_DATA_SRC_NONE;
	if (type & PERF_SAMPLE_DATA_SRC) {
		OVERFLOW_CHECK_u64(array);
		data->data_src = *array;
		array++;
	}

	data->transaction = 0;
	if (type & PERF_SAMPLE_TRANSACTION) {
		OVERFLOW_CHECK_u64(array);
		data->transaction = *array;
		array++;
	}

	return 0;
}

static int get_group_fd(struct perf_evsel *evsel, int cpu, int thread)
{
	struct perf_evsel *leader = evsel->leader;
	int fd;

	if (perf_evsel__is_group_leader(evsel))
		return -1;

	/*
	 * Leader must be already processed/open,
	 * if not it's a bug.
	 */
	BUG_ON(!leader->fd);

	fd = FD(leader, cpu, thread);
	BUG_ON(fd == -1);

	return fd;
}

#define __PRINT_ATTR(fmt, cast, field)  \
	fprintf(fp, "  %-19s "fmt"\n", #field, cast attr->field)

#define PRINT_ATTR_U32(field)  __PRINT_ATTR("%u" , , field)
#define PRINT_ATTR_X32(field)  __PRINT_ATTR("%#x", , field)
#define PRINT_ATTR_U64(field)  __PRINT_ATTR("%" PRIu64, (uint64_t), field)
#define PRINT_ATTR_X64(field)  __PRINT_ATTR("%#"PRIx64, (uint64_t), field)

#define PRINT_ATTR2N(name1, field1, name2, field2)	\
	fprintf(fp, "  %-19s %u    %-19s %u\n",		\
	name1, attr->field1, name2, attr->field2)

#define PRINT_ATTR2(field1, field2) \
	PRINT_ATTR2N(#field1, field1, #field2, field2)

static size_t perf_event_attr__fprintf(struct perf_event_attr *attr, FILE *fp)
{
	size_t ret = 0;

	ret += fprintf(fp, "%.60s\n", graph_dotted_line);
	ret += fprintf(fp, "perf_event_attr:\n");

	ret += PRINT_ATTR_U32(type);
	ret += PRINT_ATTR_U32(size);
	ret += PRINT_ATTR_X64(config);
	ret += PRINT_ATTR_U64(sample_period);
	ret += PRINT_ATTR_U64(sample_freq);
	ret += PRINT_ATTR_X64(sample_type);
	ret += PRINT_ATTR_X64(read_format);

	ret += PRINT_ATTR2(disabled, inherit);
	ret += PRINT_ATTR2(pinned, exclusive);
	ret += PRINT_ATTR2(exclude_user, exclude_kernel);
	ret += PRINT_ATTR2(exclude_hv, exclude_idle);
	ret += PRINT_ATTR2(mmap, comm);
	ret += PRINT_ATTR2(freq, inherit_stat);
	ret += PRINT_ATTR2(enable_on_exec, task);
	ret += PRINT_ATTR2(watermark, precise_ip);
	ret += PRINT_ATTR2(mmap_data, sample_id_all);
	ret += PRINT_ATTR2(exclude_host, exclude_guest);
	ret += PRINT_ATTR2N("excl.callchain_kern", exclude_callchain_kernel,
			    "excl.callchain_user", exclude_callchain_user);
	ret += PRINT_ATTR_U32(mmap2);

	ret += PRINT_ATTR_U32(wakeup_events);
	ret += PRINT_ATTR_U32(wakeup_watermark);
	ret += PRINT_ATTR_X32(bp_type);
	ret += PRINT_ATTR_X64(bp_addr);
	ret += PRINT_ATTR_X64(config1);
	ret += PRINT_ATTR_U64(bp_len);
	ret += PRINT_ATTR_X64(config2);
	ret += PRINT_ATTR_X64(branch_sample_type);
	ret += PRINT_ATTR_X64(sample_regs_user);
	ret += PRINT_ATTR_U32(sample_stack_user);

	ret += fprintf(fp, "%.60s\n", graph_dotted_line);

	return ret;
}

int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
{
	int cpu, thread;
	evsel->fd = xyarray__new(ncpus, nthreads, sizeof(int));

	if (evsel->fd) {
		for (cpu = 0; cpu < ncpus; cpu++) {
			for (thread = 0; thread < nthreads; thread++) {
				FD(evsel, cpu, thread) = -1;
			}
		}
	}

	return evsel->fd != NULL ? 0 : -ENOMEM;
}

void perf_evsel__free_fd(struct perf_evsel *evsel)
{
	xyarray__delete(evsel->fd);
	evsel->fd = NULL;
}

void perf_evsel__free_id(struct perf_evsel *evsel)
{
	xyarray__delete(evsel->sample_id);
	evsel->sample_id = NULL;
	zfree(&evsel->id);
}

static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
			      struct thread_map *threads)
{
	int cpu, thread;
	unsigned long flags = 0;
	int pid = -1, err;
	enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE;

	if (evsel->fd == NULL &&
	    perf_evsel__alloc_fd(evsel, cpus->nr, threads->nr) < 0)
		return -ENOMEM;

#if 0
	if (evsel->cgrp) {
		flags = PERF_FLAG_PID_CGROUP;
		pid = evsel->cgrp->fd;
	}

fallback_missing_features:
	if (perf_missing_features.mmap2)
		evsel->attr.mmap2 = 0;
	if (perf_missing_features.exclude_guest)
		evsel->attr.exclude_guest = evsel->attr.exclude_host = 0;
retry_sample_id:
	if (perf_missing_features.sample_id_all)
		evsel->attr.sample_id_all = 0;
#endif

	if (verbose >= 2)
		perf_event_attr__fprintf(&evsel->attr, stderr);

	for (cpu = 0; cpu < cpus->nr; cpu++) {

		for (thread = 0; thread < threads->nr; thread++) {
			int group_fd;

			if (!evsel->cgrp)
				pid = threads->map[thread];

			group_fd = get_group_fd(evsel, cpu, thread);
retry_open:
			pr_debug2("sys_perf_event_open: pid %d  cpu %d  group_fd %d  flags %#lx\n",
				  pid, cpus->map[cpu], group_fd, flags);

			FD(evsel, cpu, thread) = sys_perf_event_open(&evsel->attr,
								     pid,
								     cpus->map[cpu],
								     group_fd, flags);
			if (FD(evsel, cpu, thread) < 0) {
				err = -errno;
				pr_debug2("sys_perf_event_open failed, error %d\n",
					  err);
				goto try_fallback;
			}
			set_rlimit = NO_CHANGE;
		}
	}

	return 0;

try_fallback:
	/*
	 * perf stat needs between 5 and 22 fds per CPU. When we run out
	 * of them try to increase the limits.
	 */
	if (err == -EMFILE && set_rlimit < INCREASED_MAX) {
		struct rlimit l;
		int old_errno = errno;

		if (getrlimit(RLIMIT_NOFILE, &l) == 0) {
			if (set_rlimit == NO_CHANGE)
				l.rlim_cur = l.rlim_max;
			else {
				l.rlim_cur = l.rlim_max + 1000;
				l.rlim_max = l.rlim_cur;
			}
			if (setrlimit(RLIMIT_NOFILE, &l) == 0) {
				set_rlimit++;
				errno = old_errno;
				goto retry_open;
			}
		}
		errno = old_errno;
	}

	if (err != -EINVAL || cpu > 0 || thread > 0)
		goto out_close;

#if 0
	if (!perf_missing_features.mmap2 && evsel->attr.mmap2) {
		perf_missing_features.mmap2 = true;
		goto fallback_missing_features;
	} else if (!perf_missing_features.exclude_guest &&
		   (evsel->attr.exclude_guest || evsel->attr.exclude_host)) {
		perf_missing_features.exclude_guest = true;
		goto fallback_missing_features;
	} else if (!perf_missing_features.sample_id_all) {
		perf_missing_features.sample_id_all = true;
		goto retry_sample_id;
	}
#endif

out_close:
	do {
		while (--thread >= 0) {
			close(FD(evsel, cpu, thread));
			FD(evsel, cpu, thread) = -1;
		}
		thread = threads->nr;
	} while (--cpu >= 0);
	return err;
}

void perf_evsel__close_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
{
	int cpu, thread;

	for (cpu = 0; cpu < ncpus; cpu++)
		for (thread = 0; thread < nthreads; ++thread) {
			close(FD(evsel, cpu, thread));
			FD(evsel, cpu, thread) = -1;
		}
}

void perf_evsel__close(struct perf_evsel *evsel, int ncpus, int nthreads)
{
	if (evsel->fd == NULL)
		return;

	perf_evsel__close_fd(evsel, ncpus, nthreads);
	perf_evsel__free_fd(evsel);
}

static struct {
	struct cpu_map map;
	int cpus[1];
} empty_cpu_map = {
	.map.nr	= 1,
	.cpus	= { -1, },
};

static struct {
	struct thread_map map;
	int threads[1];
} empty_thread_map = {
	.map.nr	 = 1,
	.threads = { -1, },
};

int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
		     struct thread_map *threads)
{
	if (cpus == NULL) {
		/* Work around old compiler warnings about strict aliasing */
		cpus = &empty_cpu_map.map;
	}

	if (threads == NULL)
		threads = &empty_thread_map.map;

	return __perf_evsel__open(evsel, cpus, threads);
}