5 files changed, 100 insertions, 16 deletions

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,