perf sched timehist: Handle zero sample->tid properly

Sometimes samples have tid of 0 but non-0 pid.  It ends up having a new
thread of 0 tid/pid (instead of referring idle task) since tid is used
to search matching task.  But I guess it's wrong to use 0 as a tid when
pid is set.  This patch uses tid only if it has a non-zero value or same
as pid (of 0).

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161206034010.6499-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 634d8cf..c8b3e6c 100644 (file)
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2118,7 +2118,9 @@ static struct thread *timehist_get_thread(struct perf_sched *sched,
                        pr_err("Failed to get idle thread for cpu %d.\n", sample->cpu);
 
        } else {
-               thread = machine__findnew_thread(machine, sample->pid, sample->tid);
+               /* there were samples with tid 0 but non-zero pid */
+               thread = machine__findnew_thread(machine, sample->pid,
+                                                sample->tid ?: sample->pid);
                if (thread == NULL) {
                        pr_debug("Failed to get thread for tid %d. skipping sample.\n",
                                 sample->tid);