[PATCH V3 01/11] perf evsel: Add a debug print if perf_event_open fails

[Adrian Hunter <adrian.hunter@intel.com>]

There is a debug print (at verbose level 2) for each
call to perf_event_open.  Add another debug print if
the call fails, and print the error number.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/util/evsel.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ec0cc1e..e09c7e6 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1052,6 +1052,8 @@ retry_open:
 								     group_fd, flags);
 			if (FD(evsel, cpu, thread) < 0) {
 				err = -errno;
+				pr_debug2("perf_event_open failed, error %d\n",
+					  err);
 				goto try_fallback;
 			}
 			set_rlimit = NO_CHANGE;
-- 
1.7.11.7