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-rw-r--r--tools/perf/Documentation/perf-diff.txt26
1 files changed, 21 insertions, 5 deletions
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index fdfceee0ffd0..b3b8abae62b8 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -33,21 +33,25 @@ OPTIONS
-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=::
- Sort by key(s): pid, comm, dso, symbol.
+ Sort by key(s): pid, comm, dso, symbol, cpu, parent, srcline.
+ Please see description of --sort in the perf-report man page.
-t::
--field-separator=::
@@ -89,6 +93,14 @@ OPTIONS
--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 +169,10 @@ with:
- 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:
@@ -187,4 +203,4 @@ If specified the 'Weighted diff' column is displayed with value 'd' computed as:
SEE ALSO
--------
-linkperf:perf-record[1]
+linkperf:perf-record[1], linkperf:perf-report[1]