perf diff: Add --percentage option
The --percentage option is for controlling overhead percentage
displayed. It can only receive either of "relative" or "absolute" and
affects -c delta output only.
For more information, please see previous commit same thing done to
"perf report".
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1397145720-8063-5-git-send-email-namhyung@kernel.org
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index fdfceee..fbfa119 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -33,17 +33,20 @@
-d::
--dsos=::
Only consider symbols in these dsos. CSV that understands
- file://filename entries.
+ file://filename entries. This option will affect the percentage
+ of the Baseline/Delta column. See --percentage for more info.
-C::
--comms=::
Only consider symbols in these comms. CSV that understands
- file://filename entries.
+ file://filename entries. This option will affect the percentage
+ of the Baseline/Delta column. See --percentage for more info.
-S::
--symbols=::
Only consider these symbols. CSV that understands
- file://filename entries.
+ file://filename entries. This option will affect the percentage
+ of the Baseline/Delta column. See --percentage for more info.
-s::
--sort=::
@@ -89,6 +92,14 @@
--order::
Specify compute sorting column number.
+--percentage::
+ Determine how to display the overhead percentage of filtered entries.
+ Filters can be applied by --comms, --dsos and/or --symbols options.
+
+ "relative" means it's relative to filtered entries only so that the
+ sum of shown entries will be always 100%. "absolute" means it retains
+ the original value before and after the filter is applied.
+
COMPARISON
----------
The comparison is governed by the baseline file. The baseline perf.data
@@ -157,6 +168,10 @@
- period_percent being the % of the hist entry period value within
single data file
+ - with filtering by -C, -d and/or -S, period_percent might be changed
+ relative to how entries are filtered. Use --percentage=absolute to
+ prevent such fluctuation.
+
ratio
~~~~~
If specified the 'Ratio' column is displayed with value 'r' computed as: