evsel.c

#include "evsel.h"
#include "evlist.h"
#include "../perf.h"
#include "util.h"
#include "cpumap.h"
#include "thread_map.h"

#include <unistd.h>
#include <sys/mman.h>

#include <linux/bitops.h>
#include <linux/hash.h>

#define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
#define SID(e, x, y) xyarray__entry(e->id, x, y)

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

	if (evsel != NULL) {
		evsel->idx	   = idx;
		evsel->attr	   = *attr;
		INIT_LIST_HEAD(&evsel->node);
	}

	return evsel;
}

int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
{
	evsel->fd = xyarray__new(ncpus, nthreads, sizeof(int));
	return evsel->fd != NULL ? 0 : -ENOMEM;
}

int perf_evsel__alloc_id(struct perf_evsel *evsel, int ncpus, int nthreads)
{
	evsel->id = xyarray__new(ncpus, nthreads, sizeof(struct perf_sample_id));
	return evsel->id != NULL ? 0 : -ENOMEM;
}

int perf_evsel__alloc_counts(struct perf_evsel *evsel, int ncpus)
{
	evsel->counts = zalloc((sizeof(*evsel->counts) +
				(ncpus * sizeof(struct perf_counts_values))));
	return evsel->counts != 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->id);
	evsel->id = NULL;
}

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_evlist__munmap(struct perf_evlist *evlist, int ncpus)
{
	int cpu;

	for (cpu = 0; cpu < ncpus; cpu++) {
		if (evlist->mmap[cpu].base != NULL) {
			munmap(evlist->mmap[cpu].base, evlist->mmap_len);
			evlist->mmap[cpu].base = NULL;
		}
	}
}

int perf_evlist__alloc_mmap(struct perf_evlist *evlist, int ncpus)
{
	evlist->mmap = zalloc(ncpus * sizeof(struct perf_mmap));
	return evlist->mmap != NULL ? 0 : -ENOMEM;
}

void perf_evsel__delete(struct perf_evsel *evsel)
{
	assert(list_empty(&evsel->node));
	xyarray__delete(evsel->fd);
	xyarray__delete(evsel->id);
	free(evsel);
}

int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
			      int cpu, int thread, bool scale)
{
	struct perf_counts_values count;
	size_t nv = scale ? 3 : 1;

	if (FD(evsel, cpu, thread) < 0)
		return -EINVAL;

	if (evsel->counts == NULL && perf_evsel__alloc_counts(evsel, cpu + 1) < 0)
		return -ENOMEM;

	if (readn(FD(evsel, cpu, thread), &count, nv * sizeof(u64)) < 0)
		return -errno;

	if (scale) {
		if (count.run == 0)
			count.val = 0;
		else if (count.run < count.ena)
			count.val = (u64)((double)count.val * count.ena / count.run + 0.5);
	} else
		count.ena = count.run = 0;

	evsel->counts->cpu[cpu] = count;
	return 0;
}

int __perf_evsel__read(struct perf_evsel *evsel,
		       int ncpus, int nthreads, bool scale)
{
	size_t nv = scale ? 3 : 1;
	int cpu, thread;
	struct perf_counts_values *aggr = &evsel->counts->aggr, count;

	aggr->val = 0;

	for (cpu = 0; cpu < ncpus; cpu++) {
		for (thread = 0; thread < nthreads; thread++) {
			if (FD(evsel, cpu, thread) < 0)
				continue;

			if (readn(FD(evsel, cpu, thread),
				  &count, nv * sizeof(u64)) < 0)
				return -errno;

			aggr->val += count.val;
			if (scale) {
				aggr->ena += count.ena;
				aggr->run += count.run;
			}
		}
	}

	evsel->counts->scaled = 0;
	if (scale) {
		if (aggr->run == 0) {
			evsel->counts->scaled = -1;
			aggr->val = 0;
			return 0;
		}

		if (aggr->run < aggr->ena) {
			evsel->counts->scaled = 1;
			aggr->val = (u64)((double)aggr->val * aggr->ena / aggr->run + 0.5);
		}
	} else
		aggr->ena = aggr->run = 0;

	return 0;
}

static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
			      struct thread_map *threads, bool group, bool inherit)
{
	int cpu, thread;

	if (evsel->fd == NULL &&
	    perf_evsel__alloc_fd(evsel, cpus->nr, threads->nr) < 0)
		return -1;

	for (cpu = 0; cpu < cpus->nr; cpu++) {
		int group_fd = -1;

		evsel->attr.inherit = (cpus->map[cpu] < 0) && inherit;

		for (thread = 0; thread < threads->nr; thread++) {
			FD(evsel, cpu, thread) = sys_perf_event_open(&evsel->attr,
								     threads->map[thread],
								     cpus->map[cpu],
								     group_fd, 0);
			if (FD(evsel, cpu, thread) < 0)
				goto out_close;

			if (group && group_fd == -1)
				group_fd = FD(evsel, cpu, thread);
		}
	}

	return 0;

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

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, bool group, bool inherit)
{
	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, group, inherit);
}

int perf_evsel__open_per_cpu(struct perf_evsel *evsel,
			     struct cpu_map *cpus, bool group, bool inherit)
{
	return __perf_evsel__open(evsel, cpus, &empty_thread_map.map, group, inherit);
}

int perf_evsel__open_per_thread(struct perf_evsel *evsel,
				struct thread_map *threads, bool group, bool inherit)
{
	return __perf_evsel__open(evsel, &empty_cpu_map.map, threads, group, inherit);
}

static int __perf_evlist__mmap(struct perf_evlist *evlist, int cpu, int prot,
			       int mask, int fd)
{
	evlist->mmap[cpu].prev = 0;
	evlist->mmap[cpu].mask = mask;
	evlist->mmap[cpu].base = mmap(NULL, evlist->mmap_len, prot,
				      MAP_SHARED, fd, 0);
	if (evlist->mmap[cpu].base == MAP_FAILED)
		return -1;

	perf_evlist__add_pollfd(evlist, fd);
	return 0;
}

static int perf_evlist__id_hash(struct perf_evlist *evlist, struct perf_evsel *evsel,
			       int cpu, int thread, int fd)
{
	struct perf_sample_id *sid;
	u64 read_data[4] = { 0, };
	int hash, id_idx = 1; /* The first entry is the counter value */

	if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
	    read(fd, &read_data, sizeof(read_data)) == -1)
		return -1;

	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		++id_idx;
	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		++id_idx;

	sid = SID(evsel, cpu, thread);
	sid->id = read_data[id_idx];
	sid->evsel = evsel;
	hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
	hlist_add_head(&sid->node, &evlist->heads[hash]);
	return 0;
}

/** perf_evlist__mmap - Create per cpu maps to receive events
 *
 * @evlist - list of events
 * @cpus - cpu map being monitored
 * @threads - threads map being monitored
 * @pages - map length in pages
 * @overwrite - overwrite older events?
 *
 * If overwrite is false the user needs to signal event consuption using:
 *
 *	struct perf_mmap *m = &evlist->mmap[cpu];
 *	unsigned int head = perf_mmap__read_head(m);
 *
 *	perf_mmap__write_tail(m, head)
 */
int perf_evlist__mmap(struct perf_evlist *evlist, struct cpu_map *cpus,
		      struct thread_map *threads, int pages, bool overwrite)
{
	unsigned int page_size = sysconf(_SC_PAGE_SIZE);
	int mask = pages * page_size - 1, cpu;
	struct perf_evsel *first_evsel, *evsel;
	int thread, prot = PROT_READ | (overwrite ? 0 : PROT_WRITE);

	if (evlist->mmap == NULL &&
	    perf_evlist__alloc_mmap(evlist, cpus->nr) < 0)
		return -ENOMEM;

	if (evlist->pollfd == NULL &&
	    perf_evlist__alloc_pollfd(evlist, cpus->nr, threads->nr) < 0)
		return -ENOMEM;

	evlist->mmap_len = (pages + 1) * page_size;
	first_evsel = list_entry(evlist->entries.next, struct perf_evsel, node);

	list_for_each_entry(evsel, &evlist->entries, node) {
		if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
		    evsel->id == NULL &&
		    perf_evsel__alloc_id(evsel, cpus->nr, threads->nr) < 0)
			return -ENOMEM;

		for (cpu = 0; cpu < cpus->nr; cpu++) {
			for (thread = 0; thread < threads->nr; thread++) {
				int fd = FD(evsel, cpu, thread);

				if (evsel->idx || thread) {
					if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT,
						  FD(first_evsel, cpu, 0)) != 0)
						goto out_unmap;
				} else if (__perf_evlist__mmap(evlist, cpu, prot, mask, fd) < 0)
					goto out_unmap;

				if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
				    perf_evlist__id_hash(evlist, evsel, cpu, thread, fd) < 0)
					goto out_unmap;
			}
		}
	}

	return 0;

out_unmap:
	for (cpu = 0; cpu < cpus->nr; cpu++) {
		if (evlist->mmap[cpu].base != NULL) {
			munmap(evlist->mmap[cpu].base, evlist->mmap_len);
			evlist->mmap[cpu].base = NULL;
		}
	}
	return -1;
}