[tip:perf/core] perf stat: Handle partially bad results with merging

[tip-bot for Andi Kleen <tipbot@zytor.com>]

Commit-ID:  b4229e9d4cac2295f8f04ec26acd571a391c6c37
Gitweb:     http://git.kernel.org/tip/b4229e9d4cac2295f8f04ec26acd571a391c6c37
Author:     Andi Kleen <ak@linux.intel.com>
AuthorDate: Mon, 20 Mar 2017 13:17:01 -0700
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 21 Mar 2017 16:07:00 -0300

perf stat: Handle partially bad results with merging

When any result that is being merged is bad, mark them all bad to give
consistent output in interval mode.

No before/after, because the issue was only found in theoretical review
and it is hard to reproduce

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20170320201711.14142-4-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-stat.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a4da10a..cd7dc3b 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1237,6 +1237,16 @@ static void aggr_cb(struct perf_evsel *counter, void *data, bool first)
 		if (first)
 			ad->nr++;
 		counts = perf_counts(counter->counts, cpu, 0);
+		/*
+		 * When any result is bad, make them all to give
+		 * consistent output in interval mode.
+		 */
+		if (counts->ena == 0 || counts->run == 0 ||
+		    counter->counts->scaled == -1) {
+			ad->ena = 0;
+			ad->run = 0;
+			break;
+		}
 		ad->val += counts->val;
 		ad->ena += counts->ena;
 		ad->run += counts->run;