Add Logging for Empty Traces (#968)

Summary:
Pull Request resolved: #968

Recently, we have had users seen empty traces when the system is idle leading to confusion as to whether it was caused by a bug in kineto formatting or not. This diff adds further logging to ensure that the user is aware that kineto finds no valid trace events and is expecting an empty trace.

Reviewed By: aaronenyeshi

Differential Revision: D60311331

libkineto/src/CuptiActivityProfiler.cpp

@@ -275,6 +275,8 @@ void CuptiActivityProfiler::processTraceInternal(ActivityLogger& logger) {
   VLOG(0) << "Profile time range: " << captureWindowStartTime_ << " - "
           << captureWindowEndTime_;
   logger.handleTraceStart(metadata_);
+  setCpuActivityPresent(false);
+  setGpuActivityPresent(false);
   for (auto& cpu_trace : traceBuffers_->cpu) {
     string trace_name = cpu_trace->span.name;
     VLOG(0) << "Processing CPU buffer for " << trace_name << " ("
@@ -314,6 +316,9 @@ void CuptiActivityProfiler::processTraceInternal(ActivityLogger& logger) {
       LOGGER_OBSERVER_ADD_METADATA(
           "ResourceOverhead", std::to_string(resourceOverheadCount_));
     }
+    if (!gpuActivityPresent()){
+      LOG(WARNING) << "GPU trace is empty!";
+    }
   }
 #endif // HAS_CUPTI
 #ifdef HAS_ROCTRACER
@@ -326,6 +331,9 @@ void CuptiActivityProfiler::processTraceInternal(ActivityLogger& logger) {
     LOGGER_OBSERVER_ADD_EVENT_COUNT(count);
   }
 #endif // HAS_ROCTRACER
+  if (!traceNonEmpty()) {
+    LOG(WARNING) << "No Valid Trace Events (CPU/GPU) found. Outputting empty trace.";
+  }
 
   for (const auto& session : sessions_) {
     LOG(INFO) << "Processing child profiler trace";
@@ -359,6 +367,7 @@ void CuptiActivityProfiler::processCpuTrace(
     LOG(WARNING) << "CPU trace is empty!";
     return;
   }
+  setCpuActivityPresent(true);
 
   CpuGpuSpanPair& span_pair =
       recordTraceSpan(cpuTrace.span, cpuTrace.gpuOpCount);
@@ -518,6 +527,7 @@ void CuptiActivityProfiler::handleRuntimeActivity(
     return;
   }
   runtime_activity.log(*logger);
+  setGpuActivityPresent(true);
 }
 
 void CuptiActivityProfiler::handleDriverActivity(
@@ -545,6 +555,7 @@ void CuptiActivityProfiler::handleDriverActivity(
     return;
   }
   runtime_activity.log(*logger);
+  setGpuActivityPresent(true);
 }
 
 void CuptiActivityProfiler::handleOverheadActivity(
@@ -563,6 +574,7 @@ void CuptiActivityProfiler::handleOverheadActivity(
     return;
   }
   overhead_activity.log(*logger);
+  setGpuActivityPresent(true);
 }
 
 
@@ -636,6 +648,7 @@ void CuptiActivityProfiler::handleCudaSyncActivity(
             << " stream = " <<  activity->streamId
             << " sync type = " << syncTypeString(activity->type);
     cuda_sync_activity.log(*logger);
+    setGpuActivityPresent(true);
   };
 
   if (isWaitEventSync(activity->type)) {
@@ -743,6 +756,7 @@ inline void CuptiActivityProfiler::handleGpuActivity(
   seenDeviceStreams_.insert({act.deviceId(), act.resourceId()});
 
   act.log(*logger);
+  setGpuActivityPresent(true);
   updateGpuNetSpan(act);
   if (derivedConfig_->profileActivityTypes().count(
           ActivityType::GPU_USER_ANNOTATION)) {
@@ -854,6 +868,7 @@ void CuptiActivityProfiler::handleRuntimeActivity(
     return;
   }
   runtime_activity.log(*logger);
+  setGpuActivityPresent(true);
 }
 
 inline void CuptiActivityProfiler::handleGpuActivity(

libkineto/src/CuptiActivityProfiler.h

@@ -136,6 +136,22 @@ class CuptiActivityProfiler {
     logger_ = logger;
   }
 
+ inline void setCpuActivityPresent(bool val){
+    cpuActivityPresent_ = val;
+  }
+
+  inline void setGpuActivityPresent(bool val){
+    gpuActivityPresent_ = val;
+  } 
+
+  inline bool gpuActivityPresent(){
+    return gpuActivityPresent_;
+  }
+
+  inline bool traceNonEmpty(){
+    return cpuActivityPresent_ || gpuActivityPresent_;
+  }
+
   // Synchronous control API
   void startTrace(
       const std::chrono::time_point<std::chrono::system_clock>& now) {
@@ -443,6 +459,8 @@ class CuptiActivityProfiler {
   profilerOverhead setupOverhead_;
 
   bool cpuOnly_{false};
+  bool cpuActivityPresent_{false};
+  bool gpuActivityPresent_{false};
 
   // ***************************************************************************
   // Below state is shared with external threads.