perf tools: Allow multiple threads or processes in record, stat, top

Allow a user to collect events for multiple threads or processes
using a comma separated list.

e.g., collect data on a VM and its vhost thread:
  perf top -p 21483,21485
  perf stat -p 21483,21485 -ddd
  perf record -p 21483,21485

or monitoring vcpu threads
  perf top -t 21488,21489
  perf stat -t 21488,21489 -ddd
  perf record -t 21488,21489

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1328718772-16688-1-git-send-email-dsahern@gmail.com
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/top.c b/tools/perf/util/top.c
index e4370ca..09fe579 100644
--- a/tools/perf/util/top.c
+++ b/tools/perf/util/top.c
@@ -69,11 +69,11 @@
 
 	ret += SNPRINTF(bf + ret, size - ret, "], ");
 
-	if (top->target_pid != -1)
-		ret += SNPRINTF(bf + ret, size - ret, " (target_pid: %d",
+	if (top->target_pid)
+		ret += SNPRINTF(bf + ret, size - ret, " (target_pid: %s",
 				top->target_pid);
-	else if (top->target_tid != -1)
-		ret += SNPRINTF(bf + ret, size - ret, " (target_tid: %d",
+	else if (top->target_tid)
+		ret += SNPRINTF(bf + ret, size - ret, " (target_tid: %s",
 				top->target_tid);
 	else if (top->uid_str != NULL)
 		ret += SNPRINTF(bf + ret, size - ret, " (uid: %s",
@@ -85,7 +85,7 @@
 		ret += SNPRINTF(bf + ret, size - ret, ", CPU%s: %s)",
 				top->evlist->cpus->nr > 1 ? "s" : "", top->cpu_list);
 	else {
-		if (top->target_tid != -1)
+		if (top->target_tid)
 			ret += SNPRINTF(bf + ret, size - ret, ")");
 		else
 			ret += SNPRINTF(bf + ret, size - ret, ", %d CPU%s)",