perf report: Change default callchain parameters

The default callchain parameters are set to use the flat mode and never
filter any overhead threshold of backtrace.

But flat mode is boring compared to graph mode.
Also the number of callchains may be very high if none is
filtered.

Let's change this to set the graph view and a minimum overhead of 0.5%
as default parameters.

Reported-by: Ingo Molnar <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Anton Blanchard <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

tools/perf/builtin-report.c

@@ -59,10 +59,10 @@ static regex_t		parent_regex;
 
 static int		exclude_other = 1;
 
-static char		callchain_default_opt[] = "flat,0";
+static char		callchain_default_opt[] = "graph,0.5";
 static int		callchain;
 static enum chain_mode	callchain_mode;
-static double		callchain_min_percent = 0.0;
+static double		callchain_min_percent = 0.5;
 
 static u64		sample_type;