perf diff: Add 'delta-abs' compute method
The 'delta-abs' compute method is same as 'delta' but shows entries with
bigger absolute delta first instead of sorting numerically. This is
only useful together with -o option.
Below is default output (-c delta):
$ perf diff -o 1 -c delta | grep -v ^# | head
42.22% +4.97% [kernel.kallsyms] [k] cfb_imageblit
0.62% +1.23% [kernel.kallsyms] [k] mutex_lock
+1.15% [kernel.kallsyms] [k] copy_user_generic_string
2.40% +0.95% [kernel.kallsyms] [k] bit_putcs
0.31% +0.79% [kernel.kallsyms] [k] link_path_walk
+0.64% [kernel.kallsyms] [k] kmem_cache_alloc
0.00% +0.57% [kernel.kallsyms] [k] __rcu_read_unlock
+0.45% [kernel.kallsyms] [k] alloc_set_pte
0.16% +0.45% [kernel.kallsyms] [k] menu_select
+0.41% ld-2.24.so [.] do_lookup_x
Now with 'delta-abs' it shows entries have bigger delta value either
positive or negative.
$ perf diff -o 1 -c delta-abs | grep -v ^# | head
42.22% +4.97% [kernel.kallsyms] [k] cfb_imageblit
12.72% -3.01% [kernel.kallsyms] [k] intel_idle
9.72% -1.31% [unknown] [.] 0x0000000000411343
0.62% +1.23% [kernel.kallsyms] [k] mutex_lock
2.40% +0.95% [kernel.kallsyms] [k] bit_putcs
0.31% +0.79% [kernel.kallsyms] [k] link_path_walk
1.35% -0.71% [kernel.kallsyms] [k] smp_call_function_single
0.00% +0.57% [kernel.kallsyms] [k] __rcu_read_unlock
0.16% +0.45% [kernel.kallsyms] [k] menu_select
0.72% -0.44% [kernel.kallsyms] [k] lookup_fast
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170210073614.24584-2-namhyung@kernel.org
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 3e9490b..af80284 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -86,7 +86,7 @@
-c::
--compute::
- Differential computation selection - delta,ratio,wdiff (default is delta).
+ Differential computation selection - delta,ratio,wdiff,delta-abs (default is delta).
See COMPARISON METHODS section for more info.
-p::
@@ -181,6 +181,10 @@
relative to how entries are filtered. Use --percentage=absolute to
prevent such fluctuation.
+delta-abs
+~~~~~~~~~
+Same as 'delta` method, but sort the result with the absolute values.
+
ratio
~~~~~
If specified the 'Ratio' column is displayed with value 'r' computed as: