perf report: Make -D print sampled CPU

It is useful to know on which CPU a sample was captured on.
The information is captured with perf record -R but it was
not printed out by perf report -D. This patch adds this.

When -R is not used, cpu is set to -1to indicate that
the CPU is unknown (it is not captured).

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4bff964c.e88cd80a.3106.7d31@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -157,8 +157,9 @@ static int process_sample_event(event_t *event, struct perf_session *session)
 
 	event__parse_sample(event, session->sample_type, &data);
 
-	dump_printf("(IP, %d): %d/%d: %#Lx period: %Ld\n", event->header.misc,
-		    data.pid, data.tid, data.ip, data.period);
+	dump_printf("(IP, %d): %d/%d: %#Lx period: %Ld cpu:%d\n",
+		    event->header.misc, data.pid, data.tid, data.ip,
+		    data.period, data.cpu);
 
 	if (session->sample_type & PERF_SAMPLE_CALLCHAIN) {
 		unsigned int i;

tools/perf/util/event.c

@@ -765,7 +765,8 @@ int event__parse_sample(event_t *event, u64 type, struct sample_data *data)
 		u32 *p = (u32 *)array;
 		data->cpu = *p;
 		array++;
-	}
+	} else
+		data->cpu = -1;
 
 	if (type & PERF_SAMPLE_PERIOD) {
 		data->period = *array;