litmus tracing: expose scheduling overhead

move the switch_from/switch_to trace macros so that the
scheduling overhead shows up more clearly in the traces

1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 1a5d73e744..a3e4ad1b15 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3657,6 +3657,8 @@ need_resched:
 need_resched_nonpreemptible:
         TS_SCHED_START;
 
+        sched_trace_task_switch_away(prev);
+
         schedule_debug(prev);
 
         /*
@@ -3692,8 +3694,6 @@ need_resched_nonpreemptible:
                 rq->nr_switches++;
                 rq->curr = next;
                 ++*switch_count;
-                sched_trace_task_switch_away(prev);
-                sched_trace_task_switch_to(next);
 
                 TS_SCHED_END(next);
                 TS_CXS_START(next);
@@ -3707,6 +3707,8 @@ need_resched_nonpreemptible:
 
         tick_no_rqlock();
 
+        sched_trace_task_switch_to(current);
+
         if (unlikely(reacquire_kernel_lock(current) < 0)) {
                 cpu = smp_processor_id();
                 rq = cpu_rq(cpu);