linux-kernel - [tip:perf/core] perf stat: Don' t print bogus data on -e instructions

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Message-ID: <tip-3e7a081796146f97f166d77a655c0eb585065077@git.kernel.org>
Date:	Mon, 14 Oct 2013 22:29:25 -0700
From:	tip-bot for Ramkumar Ramachandra <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	acme@...hat.com, linux-kernel@...r.kernel.org, paulus@...ba.org,
	hpa@...or.com, mingo@...nel.org, a.p.zijlstra@...llo.nl,
	tglx@...utronix.de, artagnon@...il.com
Subject: [tip:perf/core] perf stat: Don'
 t print bogus data on -e instructions

Commit-ID:  3e7a081796146f97f166d77a655c0eb585065077
Gitweb:     http://git.kernel.org/tip/3e7a081796146f97f166d77a655c0eb585065077
Author:     Ramkumar Ramachandra <artagnon@...il.com>
AuthorDate: Tue, 1 Oct 2013 14:06:44 +0530
Committer:  Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Fri, 11 Oct 2013 12:17:35 -0300

perf stat: Don't print bogus data on -e instructions

When only the instructions event is requested:

$ perf stat -e instructions git s
M  builtin-stat.c

 Performance counter stats for 'git s':

       917,453,420 instructions              #    0.00  insns per cycle

       0.213002926 seconds time elapsed

The 0.00 insns per cycle comment in the output is totally bogus and
misleading. It happens because update_shadow_stats() doesn't touch
runtime_cycles_stats when only the instructions event is requested. So,
omit printing the bogus data altogether.

Signed-off-by: Ramkumar Ramachandra <artagnon@...il.com>
Acked-by: Ingo Molnar <mingo@...nel.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Link: http://lkml.kernel.org/r/1380616604-4077-1-git-send-email-artagnon@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/builtin-stat.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ce2266c..fb02b53 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -930,11 +930,10 @@ static void abs_printout(int cpu, int nr, struct perf_evsel *evsel, double avg)
 
 	if (perf_evsel__match(evsel, HARDWARE, HW_INSTRUCTIONS)) {
 		total = avg_stats(&runtime_cycles_stats[cpu]);
-		if (total)
+		if (total) {
 			ratio = avg / total;
-
-		fprintf(output, " #   %5.2f  insns per cycle        ", ratio);
-
+			fprintf(output, " #   %5.2f  insns per cycle        ", ratio);
+		}
 		total = avg_stats(&runtime_stalled_cycles_front_stats[cpu]);
 		total = max(total, avg_stats(&runtime_stalled_cycles_back_stats[cpu]));
 
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