#2389: trace: fix time that can be ordered improperly with changes

Author: lifflander

src/vt/context/runnable_context/trace.cc

@@ -74,7 +74,8 @@ void Trace::start(TimeType time) {
   if (theSched()->getSchedulerDepth() == 0 and not theTrace()->inInvokeContext()) {
     at_sched_depth_zero_ = true;
     theTrace()->setInInvokeContext(true);
-    theTrace()->beginSchedulerLoop();
+    auto const end_between_sched_time = theTrace()->beginSchedulerLoop();
+    time = std::max(time, end_between_sched_time);
   }
 
   auto const trace_id = auto_registry::handlerTraceID(handler_);

src/vt/trace/trace.cc

@@ -429,13 +429,15 @@ void Trace::pendingSchedulerLoop() {
   between_sched_event_ = TraceProcessingTag{};
 }
 
-void Trace::beginSchedulerLoop() {
+TimeType Trace::beginSchedulerLoop() {
+  auto const cur_time = timing::getCurrentTime();
   // Always end between-loop event. The pending case is not always triggered.
-  endProcessing(between_sched_event_, timing::getCurrentTime());
+  endProcessing(between_sched_event_, cur_time);
   between_sched_event_ = TraceProcessingTag{};
 
   // Capture the current open event depth.
   event_holds_.push_back(open_events_.size());
+  return cur_time;
 }
 
 void Trace::endSchedulerLoop() {

src/vt/trace/trace.h

@@ -172,8 +172,10 @@ struct Trace : runtime::component::Component<Trace>, TraceLite {
 
   /**
    * \brief Scheduler trigger for \c sched::SchedulerEvent::BeginSchedulerLoop
+   *
+   * \return the time the between scheduler event was ended
    */
-  void beginSchedulerLoop();
+  TimeType beginSchedulerLoop();
 
   /**
    * \brief Scheduler trigger for \c sched::SchedulerEvent::EndSchedulerLoop