[PATCHSET 0/3] perf diff: Introduce delta-abs compute method

[Namhyung Kim <namhyung@kernel.org>]

Hello,

This patchset adds 'delta-abs' compute method to -c/--compute option.
The 'delta-abs' 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
             +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
     1.35%   -0.71%  [kernel.kallsyms]  [k] smp_call_function_single
             +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
     0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock

The patch 2 and 3 are to add config options to control the default
behavior of perf diff command.  I think that it's worth consider
changing the default to use 'delta-abs' method since users want to see
where the difference occurs actually (either positive or negative) IMHO.

The code is avaiable at 'perf/diff-delta-abs-v1' branch in

  git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git

Thanks,
Namhyung


Namhyung Kim (3):
  perf diff: Add 'delta-abs' compute method
  perf diff: Add diff.order config option
  perf diff: Add diff.compute config option

 tools/perf/Documentation/perf-config.txt | 12 +++++
 tools/perf/Documentation/perf-diff.txt   | 15 +++++--
 tools/perf/builtin-diff.c                | 76 ++++++++++++++++++++++++++++++--
 3 files changed, 97 insertions(+), 6 deletions(-)

-- 
2.11.0