perf report: Group stat values on global event id

There's no big value on displaying counts for every event ID, which is
one per every CPU. Rather than that, displaying the whole sum for the
event.

  $ perf record -c 100000 -e cycles:u -s test
  $ perf report -T

Before:
  #  PID   TID  cycles:u  cycles:u  cycles:u  cycles:u  ... [20 more columns of 'cycles:u']
    3339  3339         0         0         0         0
    3340  3340         0         0         0         0
    3341  3341         0         0         0         0
    3342  3342         0         0         0         0

Now:
  #  PID   TID  cycles:u
    3339  3339     19678
    3340  3340     18744
    3341  3341     17335
    3342  3342     26414
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170824162737.7813-10-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -241,7 +241,7 @@ static int process_read_event(struct perf_tool *tool,
 		const char *name = evsel ? perf_evsel__name(evsel) : "unknown";
 		int err = perf_read_values_add_value(&rep->show_threads_values,
 					   event->read.pid, event->read.tid,
-					   event->read.id,
+					   evsel->idx,
 					   name,
 					   event->read.value);
 

tools/perf/util/values.c

@@ -192,7 +192,7 @@ int perf_read_values_add_value(struct perf_read_values *values,
 	if (cindex < 0)
 		return cindex;
 
-	values->value[tindex][cindex] = value;
+	values->value[tindex][cindex] += value;
 	return 0;
 }