[tip:perf/core] perf diff: Documentation -c cycles option

[tip-bot for Jin Yao]

Commit-ID:  c8f7bc1a080b081a178bff20356cb7575d385f84
Gitweb:     https://git.kernel.org/tip/c8f7bc1a080b081a178bff20356cb7575d385f84
Author:     Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
AuthorDate: Fri, 28 Jun 2019 17:23:04 +0800
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 2 Jul 2019 13:20:51 -0300

perf diff: Documentation -c cycles option

Documentation the new computation selection 'cycles'.

 v4:
 ---
 Change the column 'Block cycles diff [start:end]' to
 '[Program Block Range] Cycles Diff'

Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Reviewed-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Jin Yao <yao.jin@xxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1561713784-30533-8-git-send-email-yao.jin@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/Documentation/perf-diff.txt | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index facd91e4e945..d5cc15e651cf 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -90,9 +90,10 @@ OPTIONS
 
 -c::
 --compute::
-        Differential computation selection - delta, ratio, wdiff, delta-abs
-        (default is delta-abs).  Default can be changed using diff.compute
-        config option.  See COMPARISON METHODS section for more info.
+        Differential computation selection - delta, ratio, wdiff, cycles,
+        delta-abs (default is delta-abs).  Default can be changed using
+        diff.compute config option.  See COMPARISON METHODS section for
+        more info.
 
 -p::
 --period::
@@ -280,6 +281,16 @@ If specified the 'Weighted diff' column is displayed with value 'd' computed as:
     - WEIGHT-A being the weight of the data file
     - WEIGHT-B being the weight of the baseline data file
 
+cycles
+~~~~~~
+If specified the '[Program Block Range] Cycles Diff' column is displayed.
+It displays the cycles difference of same program basic block amongst
+two perf.data. The program basic block is the code between two branches.
+
+'[Program Block Range]' indicates the range of a program basic block.
+Source line is reported if it can be found otherwise uses symbol+offset
+instead.
+
 SEE ALSO
 --------
 linkperf:perf-record[1], linkperf:perf-report[1]