9 files changed, 135 insertions, 29 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index f82480fa7f27..40088a5848d6 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -262,13 +262,16 @@ static bool perf_evlist__equal(struct perf_evlist *evlist,
 
 static void open_counters(struct perf_evlist *evlist)
 {
-        struct perf_evsel *pos;
+        struct perf_evsel *pos, *first;
 
         if (evlist->cpus->map[0] < 0)
                 no_inherit = true;
 
+        first = list_entry(evlist->entries.next, struct perf_evsel, node);
+
         list_for_each_entry(pos, &evlist->entries, node) {
                 struct perf_event_attr *attr = &pos->attr;
+                struct xyarray *group_fd = NULL;
                 /*
                  * Check if parse_single_tracepoint_event has already asked for
                  * PERF_SAMPLE_TIME.
@@ -283,11 +286,15 @@ static void open_counters(struct perf_evlist *evlist)
                  */
                 bool time_needed = attr->sample_type & PERF_SAMPLE_TIME;
 
+                if (group && pos != first)
+                        group_fd = first->fd;
+
                 config_attr(pos, evlist);
 retry_sample_id:
                 attr->sample_id_all = sample_id_all_avail ? 1 : 0;
 try_again:
-                if (perf_evsel__open(pos, evlist->cpus, evlist->threads, group) < 0) {
+                if (perf_evsel__open(pos, evlist->cpus, evlist->threads, group,
+                                     group_fd) < 0) {
                         int err = errno;
 
                         if (err == EPERM || err == EACCES) {
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 7ce65f52415e..7d98676808d8 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -278,9 +278,14 @@ struct stats			runtime_itlb_cache_stats[MAX_NR_CPUS];
 struct stats                    runtime_dtlb_cache_stats[MAX_NR_CPUS];
 struct stats                    walltime_nsecs_stats;
 
-static int create_perf_stat_counter(struct perf_evsel *evsel)
+static int create_perf_stat_counter(struct perf_evsel *evsel,
+                                    struct perf_evsel *first)
 {
         struct perf_event_attr *attr = &evsel->attr;
+        struct xyarray *group_fd = NULL;
+
+        if (group && evsel != first)
+                group_fd = first->fd;
 
         if (scale)
                 attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
@@ -289,14 +294,15 @@ static int create_perf_stat_counter(struct perf_evsel *evsel)
         attr->inherit = !no_inherit;
 
         if (system_wide)
-                return perf_evsel__open_per_cpu(evsel, evsel_list->cpus, group);
-
+                return perf_evsel__open_per_cpu(evsel, evsel_list->cpus,
+                                                group, group_fd);
         if (target_pid == -1 && target_tid == -1) {
                 attr->disabled = 1;
                 attr->enable_on_exec = 1;
         }
 
-        return perf_evsel__open_per_thread(evsel, evsel_list->threads, group);
+        return perf_evsel__open_per_thread(evsel, evsel_list->threads,
+                                           group, group_fd);
 }
 
 /*
@@ -396,7 +402,7 @@ static int read_counter(struct perf_evsel *counter)
 static int run_perf_stat(int argc __used, const char **argv)
 {
         unsigned long long t0, t1;
-        struct perf_evsel *counter;
+        struct perf_evsel *counter, *first;
         int status = 0;
         int child_ready_pipe[2], go_pipe[2];
         const bool forks = (argc > 0);
@@ -453,8 +459,10 @@ static int run_perf_stat(int argc __used, const char **argv)
                 close(child_ready_pipe[0]);
         }
 
+        first = list_entry(evsel_list->entries.next, struct perf_evsel, node);
+
         list_for_each_entry(counter, &evsel_list->entries, node) {
-                if (create_perf_stat_counter(counter) < 0) {
+                if (create_perf_stat_counter(counter, first) < 0) {
                         if (errno == EINVAL || errno == ENOSYS || errno == ENOENT) {
                                 if (verbose)
                                         ui__warning("%s event is not supported by the kernel.\n",
diff --git a/tools/perf/builtin-test.c b/tools/perf/builtin-test.c
index efe696f936e2..831d1baeac37 100644
--- a/tools/perf/builtin-test.c
+++ b/tools/perf/builtin-test.c
@@ -291,7 +291,7 @@ static int test__open_syscall_event(void)
                 goto out_thread_map_delete;
         }
 
-        if (perf_evsel__open_per_thread(evsel, threads, false) < 0) {
+        if (perf_evsel__open_per_thread(evsel, threads, false, NULL) < 0) {
                 pr_debug("failed to open counter: %s, "
                          "tweak /proc/sys/kernel/perf_event_paranoid?\n",
                          strerror(errno));
@@ -366,7 +366,7 @@ static int test__open_syscall_event_on_all_cpus(void)
                 goto out_thread_map_delete;
         }
 
-        if (perf_evsel__open(evsel, cpus, threads, false) < 0) {
+        if (perf_evsel__open(evsel, cpus, threads, false, NULL) < 0) {
                 pr_debug("failed to open counter: %s, "
                          "tweak /proc/sys/kernel/perf_event_paranoid?\n",
                          strerror(errno));
@@ -531,7 +531,7 @@ static int test__basic_mmap(void)
 
                 perf_evlist__add(evlist, evsels[i]);
 
-                if (perf_evsel__open(evsels[i], cpus, threads, false) < 0) {
+                if (perf_evsel__open(evsels[i], cpus, threads, false, NULL) < 0) {
                         pr_debug("failed to open counter: %s, "
                                  "tweak /proc/sys/kernel/perf_event_paranoid?\n",
                                  strerror(errno));
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 7a871714d44e..d2fc7542e826 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -834,10 +834,16 @@ static void perf_session__mmap_read(struct perf_session *self)
 
 static void start_counters(struct perf_evlist *evlist)
 {
-        struct perf_evsel *counter;
+        struct perf_evsel *counter, *first;
+
+        first = list_entry(evlist->entries.next, struct perf_evsel, node);
 
         list_for_each_entry(counter, &evlist->entries, node) {
                 struct perf_event_attr *attr = &counter->attr;
+                struct xyarray *group_fd = NULL;
+
+                if (group && counter != first)
+                        group_fd = first->fd;
 
                 attr->sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 
@@ -860,7 +866,8 @@ static void start_counters(struct perf_evlist *evlist)
                 attr->inherit = inherit;
 try_again:
                 if (perf_evsel__open(counter, top.evlist->cpus,
-                                     top.evlist->threads, group) < 0) {
+                                     top.evlist->threads, group,
+                                     group_fd) < 0) {
                         int err = errno;
 
                         if (err == EPERM || err == EACCES) {
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 2f6bc89027da..fbb4b4ab9cc6 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -539,3 +539,33 @@ void perf_evlist__set_selected(struct perf_evlist *evlist,
 {
         evlist->selected = evsel;
 }
+
+int perf_evlist__open(struct perf_evlist *evlist, bool group)
+{
+        struct perf_evsel *evsel, *first;
+        int err, ncpus, nthreads;
+
+        first = list_entry(evlist->entries.next, struct perf_evsel, node);
+
+        list_for_each_entry(evsel, &evlist->entries, node) {
+                struct xyarray *group_fd = NULL;
+
+                if (group && evsel != first)
+                        group_fd = first->fd;
+
+                err = perf_evsel__open(evsel, evlist->cpus, evlist->threads,
+                                       group, group_fd);
+                if (err < 0)
+                        goto out_err;
+        }
+
+        return 0;
+out_err:
+        ncpus = evlist->cpus ? evlist->cpus->nr : 1;
+        nthreads = evlist->threads ? evlist->threads->nr : 1;
+
+        list_for_each_entry_reverse(evsel, &evlist->entries, node)
+                perf_evsel__close(evsel, ncpus, nthreads);
+
+        return err;
+}
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 6be71fc57794..1779ffef7828 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -50,6 +50,8 @@ struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id);
 
 union perf_event *perf_evlist__mmap_read(struct perf_evlist *self, int idx);
 
+int perf_evlist__open(struct perf_evlist *evlist, bool group);
+
 int perf_evlist__alloc_mmap(struct perf_evlist *evlist);
 int perf_evlist__mmap(struct perf_evlist *evlist, int pages, bool overwrite);
 void perf_evlist__munmap(struct perf_evlist *evlist);
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index b46f6e4bff3c..e42626422587 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -16,6 +16,7 @@
 #include "thread_map.h"
 
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
+#define GROUP_FD(group_fd, cpu) (*(int *)xyarray__entry(group_fd, cpu, 0))
 
 int __perf_evsel__sample_size(u64 sample_type)
 {
@@ -204,15 +205,16 @@ int __perf_evsel__read(struct perf_evsel *evsel,
 }
 
 static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
-                              struct thread_map *threads, bool group)
+                              struct thread_map *threads, bool group,
+                              struct xyarray *group_fds)
 {
         int cpu, thread;
         unsigned long flags = 0;
-        int pid = -1;
+        int pid = -1, err;
 
         if (evsel->fd == NULL &&
             perf_evsel__alloc_fd(evsel, cpus->nr, threads->nr) < 0)
-                return -1;
+                return -ENOMEM;
 
         if (evsel->cgrp) {
                 flags = PERF_FLAG_PID_CGROUP;
@@ -220,7 +222,7 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
         }
 
         for (cpu = 0; cpu < cpus->nr; cpu++) {
-                int group_fd = -1;
+                int group_fd = group_fds ? GROUP_FD(group_fds, cpu) : -1;
 
                 for (thread = 0; thread < threads->nr; thread++) {
 
@@ -231,8 +233,10 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
                                                                      pid,
                                                                      cpus->map[cpu],
                                                                      group_fd, flags);
-                        if (FD(evsel, cpu, thread) < 0)
+                        if (FD(evsel, cpu, thread) < 0) {
+                                err = -errno;
                                 goto out_close;
+                        }
 
                         if (group && group_fd == -1)
                                 group_fd = FD(evsel, cpu, thread);
@@ -249,7 +253,17 @@ out_close:
                 }
                 thread = threads->nr;
         } while (--cpu >= 0);
-        return -1;
+        return err;
+}
+
+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);
+        evsel->fd = NULL;
 }
 
 static struct {
@@ -269,7 +283,8 @@ static struct {
 };
 
 int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
-                     struct thread_map *threads, bool group)
+                     struct thread_map *threads, bool group,
+                     struct xyarray *group_fd)
 {
         if (cpus == NULL) {
                 /* Work around old compiler warnings about strict aliasing */
@@ -279,19 +294,23 @@ int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
         if (threads == NULL)
                 threads = &empty_thread_map.map;
 
-        return __perf_evsel__open(evsel, cpus, threads, group);
+        return __perf_evsel__open(evsel, cpus, threads, group, group_fd);
 }
 
 int perf_evsel__open_per_cpu(struct perf_evsel *evsel,
-                             struct cpu_map *cpus, bool group)
+                             struct cpu_map *cpus, bool group,
+                             struct xyarray *group_fd)
 {
-        return __perf_evsel__open(evsel, cpus, &empty_thread_map.map, group);
+        return __perf_evsel__open(evsel, cpus, &empty_thread_map.map, group,
+                                  group_fd);
 }
 
 int perf_evsel__open_per_thread(struct perf_evsel *evsel,
-                                struct thread_map *threads, bool group)
+                                struct thread_map *threads, bool group,
+                                struct xyarray *group_fd)
 {
-        return __perf_evsel__open(evsel, &empty_cpu_map.map, threads, group);
+        return __perf_evsel__open(evsel, &empty_cpu_map.map, threads, group,
+                                  group_fd);
 }
 
 static int perf_event__parse_id_sample(const union perf_event *event, u64 type,
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index e9a31554e265..b1d15e6f7ae3 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -82,11 +82,15 @@ void perf_evsel__free_id(struct perf_evsel *evsel);
 void perf_evsel__close_fd(struct perf_evsel *evsel, int ncpus, int nthreads);
 
 int perf_evsel__open_per_cpu(struct perf_evsel *evsel,
-                             struct cpu_map *cpus, bool group);
+                             struct cpu_map *cpus, bool group,
+                             struct xyarray *group_fds);
 int perf_evsel__open_per_thread(struct perf_evsel *evsel,
-                                struct thread_map *threads, bool group);
+                                struct thread_map *threads, bool group,
+                                struct xyarray *group_fds);
 int perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
-                     struct thread_map *threads, bool group);
+                     struct thread_map *threads, bool group,
+                     struct xyarray *group_fds);
+void perf_evsel__close(struct perf_evsel *evsel, int ncpus, int nthreads);
 
 #define perf_evsel__match(evsel, t, c)          \
         (evsel->attr.type == PERF_TYPE_##t &&   \
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 7624324efad4..9dd47a4f2596 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -623,7 +623,11 @@ static PyObject *pyrf_evsel__open(struct pyrf_evsel *pevsel,
                 cpus = ((struct pyrf_cpu_map *)pcpus)->cpus;
 
         evsel->attr.inherit = inherit;
-        if (perf_evsel__open(evsel, cpus, threads, group) < 0) {
+        /*
+         * This will group just the fds for this single evsel, to group
+         * multiple events, use evlist.open().
+         */
+        if (perf_evsel__open(evsel, cpus, threads, group, NULL) < 0) {
                 PyErr_SetFromErrno(PyExc_OSError);
                 return NULL;
         }
@@ -814,6 +818,25 @@ static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist,
         return Py_None;
 }
 
+static PyObject *pyrf_evlist__open(struct pyrf_evlist *pevlist,
+                                   PyObject *args, PyObject *kwargs)
+{
+        struct perf_evlist *evlist = &pevlist->evlist;
+        int group = 0;
+        static char *kwlist[] = { "group", NULL };
+
+        if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|OOii", kwlist, &group))
+                return NULL;
+
+        if (perf_evlist__open(evlist, group) < 0) {
+                PyErr_SetFromErrno(PyExc_OSError);
+                return NULL;
+        }
+
+        Py_INCREF(Py_None);
+        return Py_None;
+}
+
 static PyMethodDef pyrf_evlist__methods[] = {
         {
                 .ml_name  = "mmap",
@@ -822,6 +845,12 @@ static PyMethodDef pyrf_evlist__methods[] = {
                 .ml_doc   = PyDoc_STR("mmap the file descriptor table.")
         },
         {
+                .ml_name  = "open",
+                .ml_meth  = (PyCFunction)pyrf_evlist__open,
+                .ml_flags = METH_VARARGS | METH_KEYWORDS,
+                .ml_doc   = PyDoc_STR("open the file descriptors.")
+        },
+        {
                 .ml_name  = "poll",
                 .ml_meth  = (PyCFunction)pyrf_evlist__poll,
                 .ml_flags = METH_VARARGS | METH_KEYWORDS,