perf config: Add support setting variables in a config file

Add setting feature that can add config variables with their values to a
config file (i.e. user or system config file) or modify config key-value
pairs in a config file.  For the syntax examples:

    perf config [<file-option>] [section.name[=value] ...]

e.g. You can set the ui.show-headers to false with

    # perf config ui.show-headers=false

If you want to add or modify several config items, you can do like

    # perf config annotate.show_nr_jumps=false kmem.default=slab

Committer notes:

Testing it:

  $ perf config -l
  top.children=true
  report.children=false
  $
  $ perf config top.children=false
  $ perf config -l
  top.children=false
  report.children=false
  $
  $ perf config kmem.default=slab
  $ perf config -l
  top.children=false
  report.children=false
  kmem.default=slab
  $

Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Nambong Ha <over3025@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Wookje Kwon <aweee0@gmail.com>
Link: http://lkml.kernel.org/r/1478241862-31230-5-git-send-email-treeze.taeung@gmail.com
[ Combined patch with docs update with this one ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 1714b0c8c8e1..9365b75fd04f 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -8,7 +8,7 @@ perf-config - Get and set variables in a configuration file.
 SYNOPSIS
 --------
 [verse]
-'perf config' [<file-option>] [section.name ...]
+'perf config' [<file-option>] [section.name[=value] ...]
 or
 'perf config' [<file-option>] -l | --list
 
@@ -120,6 +120,23 @@ Given a $HOME/.perfconfig like this:
 		children = true
 		group = true
 
+You can hide source code of annotate feature setting the config to false with
+
+	% perf config annotate.hide_src_code=true
+
+If you want to add or modify several config items, you can do like
+
+	% perf config ui.show-headers=false kmem.default=slab
+
+To modify the sort order of report functionality in user config file(i.e. `~/.perfconfig`), do
+
+	% perf config --user report sort-order=srcline
+
+To change colors of selected line to other foreground and background colors
+in system config file (i.e. `$(sysconf)/perfconfig`), do
+
+	% perf config --system colors.selected=yellow,green
+
 To query the record mode of call graph, do
 
 	% perf config call-graph.record-mode