/// <summary>
/// Does a parallel ForEach around a non-blocking method with async/await
/// </summary>
/// <remarks>Even though Parallel.ForEach is being used with the async/await operators, it's not doing what
/// you expect; it's still not actually awaiting the tasks on the current thread so the Console.WriteLine
/// is executing much earlier than you would expect, before any of the method calls have completed.
/// NB even though Parallel.ForEach uses async/await in its lambda, it is not itself async so we
/// do not need to mark this test method as async</remarks>
private static Task ParallelForEachDelayLoopWithAsyncTests()
{
var sw = BeginExample("ParallelForEachDelayLoopWithAsyncTests starting...");
var array = new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
var sut = new NonBlockingMethod();
Parallel.ForEach(array, async(i, state) => await sut.StartIteration(i, DelayDurationOne, "ParallelForEachDelayLoopWithAsyncTests"));
sw.Stop();
Console.WriteLine($"Duration of Parallel.ForEach delay iteration loop for {array.Length} iterations delay for {DelayDurationOne} ms was {sw.ElapsedMilliseconds} ms");
return(Task.CompletedTask);
}
/// <summary>
/// Loops around a non-blocking method asynchronously but with no parallelism
/// </summary>
private static async Task DelayLoopTests()
{
var sw = BeginExample("DelayLoopTests starting...");
var sut = new NonBlockingMethod();
for (var i = 0; i < IterationCount; i++)
{
await sut.StartIteration(i, DelayDurationOne, "One");
}
sw.Stop();
Console.WriteLine($"Duration of async delay iteration loop for {IterationCount} iterations delay for {DelayDurationOne} ms was {sw.ElapsedMilliseconds} ms");
}
/// <summary>
/// Kicks off a number or tasks but instead of awaiting them it adds the tasks to a <see cref="List{Task}"/>
/// and then does a Task.WhenAll on that list.
/// </summary>
/// <remarks>Now the Console.WriteLine executes when we expect it to, after all tasks have completed. Those
/// tasks have been run in parallel though, since we weren't awaiting any individual task, just waiting
/// for them all to have completed.</remarks>
private static async Task TaskWhenAllDelayLoopTests()
{
var sw = BeginExample("TaskWhenAllDelayLoopTests starting...");
var sut = new NonBlockingMethod();
var taskList = new List <Task>();
for (var i = 1; i <= IterationCount; i++)
{
taskList.Add(sut.StartIteration(i, DelayDurationOne, "TaskWhenAllDelayLoopTests"));
}
await Task.WhenAll(taskList.ToArray());
sw.Stop();
Console.WriteLine($"Duration of Task.WhenAll delay iteration loop for {IterationCount} iterations delay for {DelayDurationOne} ms was {sw.ElapsedMilliseconds} ms");
}
/// <summary>
/// Does a parallel ForEach around a non-blocking method with async/await AND attaches the tasks to the parent
/// </summary>
/// <remarks>Even though Parallel.ForEach is being used with the async/await operators and attaching tasks
/// to the parent thread, it's still not doing what you expect; the Console.WriteLine
/// is still executing much earlier than you would expect, before any of the method calls have completed.
/// This may be a badly written test; I *THINK* what's happening here is that the Task.Factory.StartNew
/// creates a single new task (on a new thread) that does have the parent set correctly; however that
/// thread then runs the Parallel.ForEach which kicks off a bunch of new tasks, each on their own thread,
/// which aren't connected to the parent as you'd hope.</remarks>
private static async Task ParallelForEachDelayLoopWithAsyncAttachedTests()
{
var sw = BeginExample("ParallelForEachDelayLoopWithAsyncAttachedTests starting...");
var array = new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
var sut = new NonBlockingMethod();
await Task.Factory.StartNew(() =>
{
Parallel.ForEach(array,
async(i, state) => await sut.StartIteration(i, DelayDurationOne, "ParallelForEachDelayLoopWithAsyncAttachedTests"));
}, TaskCreationOptions.AttachedToParent);
sw.Stop();
Console.WriteLine($"Duration of attached Parallel.ForEach delay iteration loop for {array.Length} iterations delay for {DelayDurationOne} ms was {sw.ElapsedMilliseconds} ms");
}
/// <summary>
/// Make sure to put a breakpoint in the NonBlockingMethod.StartIteration method somewhere
/// within the extraIterativeDelay logic
/// </summary>
/// <remarks>Can use this to demo the threads, tasks and Parallel Watch windows, freezing threads/tasks,
/// switching between threads/tasks etc.</remarks>
private static async Task DemoThreadDebugging()
{
BeginExample("DemoThreadDebugging starting...");
var count = 5;
var sut = new NonBlockingMethod();
var taskList = new List <Task>();
for (int i = 1; i <= count; i++)
{
taskList.Add(sut.StartIteration(i, DelayDurationOne, "DemoThreadDebugging", true));
}
await Task.WhenAll(taskList.ToArray());
Console.WriteLine($"DemoThreadDebugging complete");
}
