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From: Taeung Song <treeze.taeung@gmail.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Wang Nan <wangnan0@huawei.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Taeung Song <treeze.taeung@gmail.com>,
	Jiri Olsa <jolsa@redhat.com>
Subject: [PATCH v3 2/7] perf annotate: Avoid division by zero when calculating percent
Date: Fri, 10 Mar 2017 02:35:36 +0900	[thread overview]
Message-ID: <1489080941-3965-3-git-send-email-treeze.taeung@gmail.com> (raw)
In-Reply-To: <1489080941-3965-1-git-send-email-treeze.taeung@gmail.com>

Currently perf-annotate with --print-line can print
-nan(0x8000000000000) because of division by zero
when calculating percent.

So if a sum of samples is zero, skip calculating percent.

Before:

    $ perf annotate --stdio -l

Sorted summary for file /home/taeung/workspace/a.out
----------------------------------------------

   32.89    -nan    7.04 a.c:38
   25.14    -nan    0.00 a.c:34
   16.26    -nan   56.34 a.c:31
   15.88    -nan    1.41 a.c:37
    5.67    -nan    0.00 a.c:39
    1.13    -nan   35.21 a.c:26
    0.95    -nan    0.00 a.c:44
    0.57    -nan    0.00 a.c:32
 Percent                 |      Source code & Disassembly of a.out for cycles (529 samples)
-----------------------------------------------------------------------------------------
                         :
...

 a.c:26    0.57    -nan    4.23 :         40081a:       mov    %edi,-0x24(%rbp)
 a.c:26    0.00    -nan    9.86 :         40081d:       mov    %rsi,-0x30(%rbp)

...

After:

    $ perf annotate --stdio -l

Sorted summary for file /home/taeung/workspace/a.out
----------------------------------------------

   32.89    0.00    7.04 a.c:38
   25.14    0.00    0.00 a.c:34
   16.26    0.00   56.34 a.c:31
   15.88    0.00    1.41 a.c:37
    5.67    0.00    0.00 a.c:39
    1.13    0.00   35.21 a.c:26
    0.95    0.00    0.00 a.c:44
    0.57    0.00    0.00 a.c:32
 Percent                 |      Source code & Disassembly of old for cycles (529 samples)
-----------------------------------------------------------------------------------------
                         :
...

a.c:26    0.57    0.00    4.23 :         40081a:       mov    %edi,-0x24(%rbp)
a.c:26    0.00    0.00    9.86 :         40081d:       mov    %rsi,-0x30(%rbp)

...

Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
---
 tools/perf/util/annotate.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index fc91c6b..9bb43cd 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1665,11 +1665,15 @@ static int symbol__get_source_line(struct symbol *sym, struct map *map,
 		src_line->nr_pcnt = nr_pcnt;
 
 		for (k = 0; k < nr_pcnt; k++) {
+			double percent = 0.0;
+
 			h = annotation__histogram(notes, evidx + k);
-			src_line->samples[k].percent = 100.0 * h->addr[i] / h->sum;
+			if (h->sum)
+				percent = 100.0 * h->addr[i] / h->sum;
 
-			if (src_line->samples[k].percent > percent_max)
-				percent_max = src_line->samples[k].percent;
+			if (percent > percent_max)
+				percent_max = percent;
+			src_line->samples[k].percent = percent;
 		}
 
 		if (percent_max <= 0.5)
-- 
2.7.4

  parent reply	other threads:[~2017-03-09 17:38 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-09 17:35 [PATCH v3 0/7] perf annotate: Fixes & Introduce --source-only and new source code view Taeung Song
2017-03-09 17:35 ` [PATCH v3 1/7] perf annotate: Use build-id dir when reading link name Taeung Song
2017-03-09 17:35 ` Taeung Song [this message]
2017-03-09 17:35 ` [PATCH v3 3/7] perf annotate: Fix missing setting nr samples on source_line Taeung Song
2017-03-09 17:35 ` [PATCH v3 4/7] perf annotate: More exactly grep -v in symbol__disassemble() Taeung Song
2017-03-09 17:35 ` [PATCH v3 5/7] perf annotate: Get correct line numbers matched with addr Taeung Song
2017-03-09 17:35 ` [PATCH v3 6/7] perf annotate: Introduce --source-only option Taeung Song
2017-03-09 17:35 ` [PATCH v3 7/7] perf annotate: Support the new source code view for TUI Taeung Song

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