1. Staying Afloat in the .NET Async Ocean
Mike Huguet
Senior Premier Field Engineer
CRM and Developer Support

2. Mike Huguet Senior Premier Field Engineer CRM and Developer Support

3. Objective
Feel comfortable in making a decision of which pattern and constructs to use

4. Agenda
Threading Basics
Async Programming
Parallel Programming

5. Agenda
Threading Basics
Async Programming
Parallel Programming

6. Asynchronous vs. Parallel
Dealing with a lot of things at once
Responsive User Interface
Prevent blocking
Can delegate to another
A.k.a.-concurrency
Parallel
Doing a lot of things at once
Requires asynchronous
Break up work or tasks

7. Example - Juggling

8. What is a thread? Unit allocated to processor time by the OS
PRISM FY16
Unit allocated to processor time by the OS
Multiple threads can be allocated per process
The OS and .NET create the effect of simultaneous thread execution
11/14/2018 2:53 PM
What is a thread?
First, let’s level set on what culture is. Culture is an outcome, it is the result of how we behave and work in our system. It is guided by decisions and what is reinforced.
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

9. Threading disadvantage?
PRISM FY16
Can strain OS resources and degrade performance
Overhead exists for managing and using threads
Cross thread communication costs
Can require resource synchronization
Adds complexity to code and is a high cause of bugs (e.g.-deadlocking, race conditions)
11/14/2018 2:53 PM
Threading disadvantage?
First, let’s level set on what culture is. Culture is an outcome, it is the result of how we behave and work in our system. It is guided by decisions and what is reinforced.
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

10. Threading benefits? Effective way to increase responsiveness
PRISM FY16
Effective way to increase responsiveness
11/14/2018 2:53 PM
Threading benefits?
First, let’s level set on what culture is. Culture is an outcome, it is the result of how we behave and work in our system. It is guided by decisions and what is reinforced.
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

11. Agenda
Threading Basics
Async Programming
Parallel Programming

12. Asynchronous Programming Patterns
Legacy
System.Threading
Async Programming Model (APM)
Task-based Async Pattern (TAP)
***Modern
Event-Based Async Programming Model (EAP)

13. System.Threading - Thread
ThreadStart
Notes
.NET 1.0
Expensive
Risky
Can be complex
*Use ThreadPool.
QueueUserWorkItem
$$$

14. System.Threading - ThreadPool
Notes
Managed a pool
Handles multi-CPU
Difficult for continuation
Single param restriction
$$$

15. Demo - Threading

16. Async Programming Model (APM)
BeginXxx
EndXxx
IAsyncResult
Notes
.NET 2.0
Supports continuation
Uses IO OS Threads
Supports cancellation
Expensive
Can be complex continuation

17. Demo – APM

18. Event-Based Async Programming Model (EAP)
XxxAsync
XxxCompleted
XxxCancelled
Notes
.NET 2.0
Expensive
Risky
Can be REALLY complex
BackgroundWorker
WebClient

19. Demo - EAP

20. Task-based Asynchronous Pattern (TAP)
XxxAsync
Task.Run
Task.Factory
.StartNew
Task<TResult>
CancellationToken
IProgress
Notes
.NET 4.0
Single method
Supports multiple typed params
Supports typed result
Supports continuation & Cancel

21. Demo – TAP

22. TAP – Async/Await XxxAsync Task Task<TResult> Progress Notes
.NET 4.5
Much easier continuation
Compiler sugar
Can be confusing
Finally blocks might not run

23. Demo – Async/Await

24. Agenda
Threading Basics
Async Programming
Parallel Programming

25. Task Parallel Library (TPL)
Parallel.For
Parallel.ForEach
Parallel.Invoke
Dataflow Blocks
Notes
.NET 4.0
Not always async
Extra overhead

27. Parallel LINQ (PLINQ) ParallelQuery AsParallel Notes
ParallelEnumerable
ParallelQuery
AsParallel
Notes
.NET 4.0
Familiar LINQ syntax
Tries to optimize loading on multiple threads and cores
Not necessarily faster

28. Demo – Parallel

29. Resources
Parallel Processing and Concurrency in the .NET Framework -
Managed Threading Best Practices -
Managed Threading Basics -
The Asynchronous Programming Models -
Asynchronous Programming with Async and Await -
Parallel Programming in the .NET Framework -