Add termination time to TaskStats

velox/exec/Task.cpp

@@ -1697,6 +1697,11 @@ ContinueFuture Task::terminate(TaskState terminalState) {
     if (taskStats_.executionEndTimeMs == 0) {
       taskStats_.executionEndTimeMs = getCurrentTimeMs();
     }
+    if (taskStats_.terminationTimeMs == 0) {
+      // In case terminate gets called multiple times somehow,
+      // this represents the first time.
+      taskStats_.terminationTimeMs = getCurrentTimeMs();
+    }
     if (not isRunningLocked()) {
       return makeFinishFutureLocked("Task::terminate");
     }
@@ -1944,6 +1949,14 @@ uint64_t Task::timeSinceEndMs() const {
   return getCurrentTimeMs() - taskStats_.executionEndTimeMs;
 }
 
+uint64_t Task::timeSinceTerminationMs() const {
+  std::lock_guard<std::mutex> l(mutex_);
+  if (taskStats_.terminationTimeMs == 0UL) {
+    return 0UL;
+  }
+  return getCurrentTimeMs() - taskStats_.terminationTimeMs;
+}
+
 void Task::onTaskCompletion() {
   listeners().withRLock([&](auto& listeners) {
     if (listeners.empty()) {

velox/exec/Task.h

@@ -266,6 +266,10 @@ class Task : public std::enable_shared_from_this<Task> {
   /// Returns time (ms) since the task execution ended or zero, if not finished.
   uint64_t timeSinceEndMs() const;
 
+  /// Returns time (ms) since the task was terminated or zero, if not terminated
+  /// yet.
+  uint64_t timeSinceTerminationMs() const;
+
   /// Returns the total number of drivers in the output pipeline, e.g. the
   /// pipeline that produces the results.
   uint32_t numOutputDrivers() const {

velox/exec/TaskStats.h

@@ -73,6 +73,11 @@ struct TaskStats {
   /// and results have been consumed.
   uint64_t endTimeMs{0};
 
+  /// Epoch time (ms) when the task was terminated, i.e. its terminal state
+  /// has been set, whether by finishing successfully or with an error, or
+  /// being cancelled or aborted.
+  uint64_t terminationTimeMs{0};
+
   /// Total number of drivers.
   uint64_t numTotalDrivers{0};
   /// The number of completed drivers (which slots are null in Task 'drivers_'