/// <summary>
/// Outputs a WaitBegin ETW event, and augments the continuation action to output a WaitEnd ETW event.
/// </summary>
/// <param name="task">The task being awaited.</param>
/// <param name="continuation">The action to invoke when the await operation completes.</param>
/// <returns>The action to use as the actual continuation.</returns>
private static Action OutputWaitEtwEvents(Task task, Action continuation)
{
Debug.Assert(task != null, "Need a task to wait on");
Debug.Assert(continuation != null, "Need a continuation to invoke when the wait completes");
Debug.Assert(TaskTrace.Enabled, "Should only be used when ETW tracing is enabled");
// ETW event for Task Wait Begin
var currentTaskAtBegin = Task.InternalCurrent;
TaskTrace.TaskWaitBegin_Asynchronous(
(currentTaskAtBegin != null ? currentTaskAtBegin.m_taskScheduler.Id : TaskScheduler.Default.Id),
(currentTaskAtBegin != null ? currentTaskAtBegin.Id : 0),
task.Id);
// Create a continuation action that outputs the end event and then invokes the user
// provided delegate. This incurs the allocations for the closure/delegate, but only if the event
// is enabled, and in doing so it allows us to pass the awaited task's information into the end event
// in a purely pay-for-play manner (the alternatively would be to increase the size of TaskAwaiter
// just for this ETW purpose, not pay-for-play, since GetResult would need to know whether a real yield occurred).
return(() =>
{
// ETW event for Task Wait End.
if (TaskTrace.Enabled)
{
var currentTaskAtEnd = Task.InternalCurrent;
TaskTrace.TaskWaitEnd(
(currentTaskAtEnd != null ? currentTaskAtEnd.m_taskScheduler.Id : TaskScheduler.Default.Id),
(currentTaskAtEnd != null ? currentTaskAtEnd.Id : 0),
task.Id);
}
// Invoke the original continuation provided to OnCompleted.
continuation();
});
}
/// <summary>
/// Outputs a WaitBegin ETW event, and augments the continuation action to output a WaitEnd ETW event.
/// </summary>
/// <param name="task">The task being awaited.</param>
/// <param name="continuation">The action to invoke when the await operation completes.</param>
/// <returns>The action to use as the actual continuation.</returns>
private static Action OutputWaitEtwEvents(Task task, Action continuation)
{
Debug.Assert(task != null, "Need a task to wait on");
Debug.Assert(continuation != null, "Need a continuation to invoke when the wait completes");
#if CORECLR
if (Task.s_asyncDebuggingEnabled)
{
Task.AddToActiveTasks(task);
}
var etwLog = TplEtwProvider.Log;
if (etwLog.IsEnabled())
{
// ETW event for Task Wait Begin
var currentTaskAtBegin = Task.InternalCurrent;
// If this task's continuation is another task, get it.
var continuationTask = AsyncMethodBuilderCore.TryGetContinuationTask(continuation);
etwLog.TaskWaitBegin(
(currentTaskAtBegin != null ? currentTaskAtBegin.m_taskScheduler.Id : TaskScheduler.Default.Id),
(currentTaskAtBegin != null ? currentTaskAtBegin.Id : 0),
task.Id, TplEtwProvider.TaskWaitBehavior.Asynchronous,
(continuationTask != null ? continuationTask.Id : 0));
}
#else
Debug.Assert(TaskTrace.Enabled, "Should only be used when ETW tracing is enabled");
// ETW event for Task Wait Begin
var currentTaskAtBegin = Task.InternalCurrent;
TaskTrace.TaskWaitBegin_Asynchronous(
(currentTaskAtBegin != null ? currentTaskAtBegin.m_taskScheduler.Id : TaskScheduler.Default.Id),
(currentTaskAtBegin != null ? currentTaskAtBegin.Id : 0),
task.Id);
#endif
// Create a continuation action that outputs the end event and then invokes the user
// provided delegate. This incurs the allocations for the closure/delegate, but only if the event
// is enabled, and in doing so it allows us to pass the awaited task's information into the end event
// in a purely pay-for-play manner (the alternatively would be to increase the size of TaskAwaiter
// just for this ETW purpose, not pay-for-play, since GetResult would need to know whether a real yield occurred).
#if CORECLR
return(AsyncMethodBuilderCore.CreateContinuationWrapper(continuation, (innerContinuation, innerTask) =>
{
if (Task.s_asyncDebuggingEnabled)
{
Task.RemoveFromActiveTasks(innerTask.Id);
}
TplEtwProvider innerEtwLog = TplEtwProvider.Log;
// ETW event for Task Wait End.
Guid prevActivityId = new Guid();
bool bEtwLogEnabled = innerEtwLog.IsEnabled();
if (bEtwLogEnabled)
{
var currentTaskAtEnd = Task.InternalCurrent;
innerEtwLog.TaskWaitEnd(
(currentTaskAtEnd != null ? currentTaskAtEnd.m_taskScheduler.Id : TaskScheduler.Default.Id),
(currentTaskAtEnd != null ? currentTaskAtEnd.Id : 0),
innerTask.Id);
// Ensure the continuation runs under the activity ID of the task that completed for the
// case the antecedent is a promise (in the other cases this is already the case).
if (innerEtwLog.TasksSetActivityIds && (innerTask.Options & (TaskCreationOptions)InternalTaskOptions.PromiseTask) != 0)
{
EventSource.SetCurrentThreadActivityId(TplEtwProvider.CreateGuidForTaskID(innerTask.Id), out prevActivityId);
}
}
// Invoke the original continuation provided to OnCompleted.
innerContinuation();
if (bEtwLogEnabled)
{
innerEtwLog.TaskWaitContinuationComplete(innerTask.Id);
if (innerEtwLog.TasksSetActivityIds && (innerTask.Options & (TaskCreationOptions)InternalTaskOptions.PromiseTask) != 0)
{
EventSource.SetCurrentThreadActivityId(prevActivityId);
}
}
}, task));
#else
return(() =>
{
// ETW event for Task Wait End.
if (TaskTrace.Enabled)
{
var currentTaskAtEnd = Task.InternalCurrent;
TaskTrace.TaskWaitEnd(
(currentTaskAtEnd != null ? currentTaskAtEnd.m_taskScheduler.Id : TaskScheduler.Default.Id),
(currentTaskAtEnd != null ? currentTaskAtEnd.Id : 0),
task.Id);
}
// Invoke the original continuation provided to OnCompleted.
continuation();
});
#endif
}