perf evlist: Do not poll events that use the system_wide flag

The system_wide flag causes a selected event to be opened always without
a pid.

Consequently it will never get a POLLHUP, but it is used for tracking in
combination with other events, so it should not need to be polled
anyway.

Therefore don't add it for polling.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1415715423-15563-2-git-send-email-adrian.hunter@intel.com
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 7e23dae..cfbe2b9 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -816,7 +816,15 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
                        perf_evlist__mmap_get(evlist, idx);
                }
 
-               if (__perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
+               /*
+                * The system_wide flag causes a selected event to be opened
+                * always without a pid.  Consequently it will never get a
+                * POLLHUP, but it is used for tracking in combination with
+                * other events, so it should not need to be polled anyway.
+                * Therefore don't add it for polling.
+                */
+               if (!evsel->system_wide &&
+                   __perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
                        perf_evlist__mmap_put(evlist, idx);
                        return -1;
                }