From 7aaf6b35512382329c5b2dd46b42f2bf12a5fff0 Mon Sep 17 00:00:00 2001
From: Jiri Olsa <jolsa@redhat.com>
Date: Fri, 5 Oct 2012 16:44:41 +0200
Subject: perf diff: Add ratio computation way to compare hist entries

Adding -c option to select computation method with the current 'Delta'
computation as default. Current possible values are of this option are:
'delta' and 'ratio'.

Adding 'ratio' as new computation way to compare hist entries.  If
specified the 'Ratio' column is displayed with value 'r' computed as:

  r = A->period / B->period

with:
  - A/B being matching hist entry from first/second file specified
    (or perf.data/perf.data.old) respectively.
  - period being the hist entry period value

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1349448287-18919-3-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-diff.txt | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

(limited to 'tools/perf/Documentation/perf-diff.txt')

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 6ce95858cd4..8fff0618c59 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -76,6 +76,39 @@ OPTIONS
 --baseline-only::
         Show only items with match in baseline.
 
+-c::
+--compute::
+        Differential computation selection - delta,ratio (default is delta).
+        See COMPARISON METHODS section for more info.
+
+COMPARISON METHODS
+------------------
+delta
+~~~~~
+If specified the 'Delta' column is displayed with value 'd' computed as:
+
+  d = A->period_percent - B->period_percent
+
+with:
+  - A/B being matching hist entry from first/second file specified
+    (or perf.data/perf.data.old) respectively.
+
+  - period_percent being the % of the hist entry period value within
+    single data file
+
+ratio
+~~~~~
+If specified the 'Ratio' column is displayed with value 'r' computed as:
+
+  r = A->period / B->period
+
+with:
+  - A/B being matching hist entry from first/second file specified
+    (or perf.data/perf.data.old) respectively.
+
+  - period being the hist entry period value
+
+
 SEE ALSO
 --------
 linkperf:perf-record[1]
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