perf tools: Add call-graph option support into .perfconfig

Adding call-graph option support into .perfconfig file, so it's now
possible use call-graph option like:

  [top]
        call-graph = fp

  [record]
        call-graph = dwarf,8192

Above options ONLY setup the unwind method. To enable perf record/top to
actually use it the command line option -g/-G must be specified.

The --call-graph option overloads .perfconfig setup.

Assuming above configuration:

  $ perf record -g ls
  - enables dwarf unwind with user stack size dump 8192 bytes

  $ perf top -G
  - enables frame pointer unwind

  $ perf record --call-graph=fp ls
  - enables frame pointer unwind

  $ perf top --call-graph=dwarf,4096 ls
  - enables dwarf unwind with user stack size dump 4096 bytes

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1391427883-13443-2-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 76cd510..ed99ec4 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -991,6 +991,16 @@
 	return record_parse_callchain_opt(opt, arg, unset);
 }
 
+static int perf_top_config(const char *var, const char *value, void *cb)
+{
+	struct perf_top *top = cb;
+
+	if (!strcmp(var, "top.call-graph"))
+		return record_parse_callchain(value, &top->record_opts);
+
+	return perf_default_config(var, value, cb);
+}
+
 static int
 parse_percent_limit(const struct option *opt, const char *arg,
 		    int unset __maybe_unused)
@@ -1115,6 +1125,8 @@
 	if (top.evlist == NULL)
 		return -ENOMEM;
 
+	perf_config(perf_top_config, &top);
+
 	argc = parse_options(argc, argv, options, top_usage, 0);
 	if (argc)
 		usage_with_options(top_usage, options);