perf callchain: Switch default to 'graph,0.5,caller'

Which is the most common default found in other similar tools.

Requested-by: Ingo Molnar <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: Chandler Carruth <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: https://www.youtube.com/watch?v=nXaxk27zwlk
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-report.txt

···
 	when available. Usually more convenient to use --branch-history
 	for this.
 
-	Default: fractal,0.5,callee,function.
+	Default: graph,0.5,caller
 
 --children::
 	Accumulate callchain of children to parent entry so that then can

tools/perf/builtin-report.c

···
 	bool has_br_stack = false;
 	int branch_mode = -1;
 	bool branch_call_mode = false;
-	char callchain_default_opt[] = "fractal,0.5,callee";
+	char callchain_default_opt[] = "graph,0.5,caller";
 	const char * const report_usage[] = {
 		"perf report [<options>]",
 		NULL
···
 		    "Only display entries with parent-match"),
 	OPT_CALLBACK_DEFAULT('g', "call-graph", &report, "output_type,min_percent[,print_limit],call_order[,branch]",
 		     "Display callchains using output_type (graph, flat, fractal, or none) , min percent threshold, optional print limit, callchain order, key (function or address), add branches. "
-		     "Default: fractal,0.5,callee,function", &report_parse_callchain_opt, callchain_default_opt),
+		     "Default: graph,0.5,caller", &report_parse_callchain_opt, callchain_default_opt),
 	OPT_BOOLEAN(0, "children", &symbol_conf.cumulate_callchain,
 		    "Accumulate callchains of children and show total overhead as well"),
 	OPT_INTEGER(0, "max-stack", &report.max_stack,

tools/perf/util/util.c

···
 #include "callchain.h"
 
 struct callchain_param	callchain_param = {
-	.mode	= CHAIN_GRAPH_REL,
+	.mode	= CHAIN_GRAPH_ABS,
 	.min_percent = 0.5,
-	.order  = ORDER_CALLEE,
+	.order  = ORDER_CALLER,
 	.key	= CCKEY_FUNCTION
 };