perf evlist: Introduce perf_evlist__new_dummy constructor
For case where all we need is an evlist with just an "dummy" evsel,
like in some 'perf test' entries.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-q52le0pblm2k3ncvyilelr9z@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index b9eac0d..fa6dbf0 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -68,6 +68,18 @@
return evlist;
}
+struct perf_evlist *perf_evlist__new_dummy(void)
+{
+ struct perf_evlist *evlist = perf_evlist__new();
+
+ if (evlist && perf_evlist__add_dummy(evlist)) {
+ perf_evlist__delete(evlist);
+ evlist = NULL;
+ }
+
+ return evlist;
+}
+
/**
* perf_evlist__set_id_pos - set the positions of event ids.
* @evlist: selected event list
@@ -248,6 +260,22 @@
return -ENOMEM;
}
+int perf_evlist__add_dummy(struct perf_evlist *evlist)
+{
+ struct perf_event_attr attr = {
+ .type = PERF_TYPE_SOFTWARE,
+ .config = PERF_COUNT_SW_DUMMY,
+ .size = sizeof(attr), /* to capture ABI version */
+ };
+ struct perf_evsel *evsel = perf_evsel__new(&attr);
+
+ if (evsel == NULL)
+ return -ENOMEM;
+
+ perf_evlist__add(evlist, evsel);
+ return 0;
+}
+
static int perf_evlist__add_attrs(struct perf_evlist *evlist,
struct perf_event_attr *attrs, size_t nr_attrs)
{