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>
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 6ce9585..8fff061 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -76,6 +76,39 @@
--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]