perf machine: Add machine__thread_exec_comm()

Add machine__thread_exec_comm() to return the comm that matches the last
exec, if the comm_exec flag is present, or the last comm otherwise.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1406786474-9306-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index ea3e09f..b093b93 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -31,6 +31,7 @@
 
 	machine->symbol_filter = NULL;
 	machine->id_hdr_size = 0;
+	machine->comm_exec = false;
 
 	machine->root_dir = strdup(root_dir);
 	if (machine->root_dir == NULL)
@@ -179,6 +180,19 @@
 	}
 }
 
+void machines__set_comm_exec(struct machines *machines, bool comm_exec)
+{
+	struct rb_node *nd;
+
+	machines->host.comm_exec = comm_exec;
+
+	for (nd = rb_first(&machines->guests); nd; nd = rb_next(nd)) {
+		struct machine *machine = rb_entry(nd, struct machine, rb_node);
+
+		machine->comm_exec = comm_exec;
+	}
+}
+
 struct machine *machines__find(struct machines *machines, pid_t pid)
 {
 	struct rb_node **p = &machines->guests.rb_node;
@@ -398,6 +412,15 @@
 	return __machine__findnew_thread(machine, pid, tid, false);
 }
 
+struct comm *machine__thread_exec_comm(struct machine *machine,
+				       struct thread *thread)
+{
+	if (machine->comm_exec)
+		return thread__exec_comm(thread);
+	else
+		return thread__comm(thread);
+}
+
 int machine__process_comm_event(struct machine *machine, union perf_event *event,
 				struct perf_sample *sample)
 {
@@ -406,6 +429,9 @@
 							event->comm.tid);
 	bool exec = event->header.misc & PERF_RECORD_MISC_COMM_EXEC;
 
+	if (exec)
+		machine->comm_exec = true;
+
 	if (dump_trace)
 		perf_event__fprintf_comm(event, stdout);