Viacheslav Eremin | My multithreading learning conspectus

(Task) Task (2016)

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1. APM (Asynchronous Programming Model).
2. EAP (Event-based Asynchronous Pattern).
3. TAP (Task-based Asynchronous Pattern).
4. Ms documentation about Task and Thread.
5. Threading and Task synchronization.
6. BackgroundWorker.
7. Parallel library.
8. Reactive NET extension
9. MultiThreading in NET Core 6.
10. Delegate Task vs Promise Task (.NET).
11. .NET Promise task is the same than Promise in JS.
12. Delegate Task vs Promise Task Article.
13. Task Yield.
14. Other point of view

1. APM (Asynchronous Programming Model).

Working since NET 1.1 and currently not implemented in .NET CORE, run synchronously.

Contains BeginRead/EndRead, IsyncResult interface, State object with IsComplete flag.

Common scheme:

    Dim RequestState As New With { ...}
    Sub Task()
        Dim Request As Net.HttpWebRequest = Net.HttpWebRequest.Create("")
        Dim Res As IAsyncResult = CType(Request.BeginGetResponse(New AsyncCallback(AddressOf RespCallback), RequestState), IAsyncResult)
    End Sub
    Sub RespCallback(ByVal ar As IAsyncResult)
    End Sub

Examples on my site.

Full documentation. Asynchronous Programming Model.pdf

2. EAP (Event-based Asynchronous Pattern).

Require method with ___Async suffix, require Event and EventHandler and EventArgs as derived type. You can provide own private delegate, own derived handler from EventHandler, and can provide own StateObject, own Cancel method. Support IProgress and ReadComplete event.

    Async Function ExecuteAsync(ByVal SshCommand As SshCommand, ByVal OutputLine As IProgress(Of SshOutputLine), ByVal CTX As CancellationToken) As Task

Examples on my site.

Full documentation. Event-based Asynchronous Pattern.pdf

3. TAP (Task-based Asynchronous Pattern).

Future.

Exception stored on StateObject
Return Task(of TResult). Any complex parameters you want to rerurn you should return as tuples.
ContinueWith - waiting result by Task class OR Await as language future. Also support ContinueWhenAll/ContinueWhenAny.
Support interface IProgress and CancelationTokenSource.Token
TaskFactory.StartNew (Action (Of T)) or (Function(of TResult) Return Task (Tresult))
Since NET 4.5 TaskFactory.StartNew has shortcut Task.Run

    Await ReadAsync(Nothing, Nothing, Nothing)
    Async Function ReadAsync(Buf, offset, count) As Task(Of Int16)
    End Function

Examples on my site.

Full documentation.

4. Ms documentation about Task and Thread.

Task
Thread

5. Threading and Task synchronization.

Future.

DOP - Decrease of parallelism

Full documentation.

6. BackgroundWorker.

Examples on my site.

Full documentation. Event-based Asynchronous Pattern.pdf

7. Parallel library.

Examples on my site.

Parallel.For - Multithreading Parsers with Parallel, CsQuery, Newtonsoft.Json, OfficeOpenXml and IAsyncResult/AsyncCallback.

Full documentation. Parallel Programming.pdf

8. Reactive NET extension.

Examples on my site.

Building TreeView by Reactive Extensions NET (Recursive observe directory, Iterator function with Yield, Windows native thread).

9. MultiThreading in NET Core 6.

Future.

Support Environment.ProcessorCount
APM working synchronously, not supported.
Parallel.ForEach working synchronously, not supported. Has replacement to Parallel.ForEachAsync.
Return ValueTask instead Task (Task (of T) return Nothing, if task call synchronously, but ValueTask return event even task run synchronously.
new operation with CancelationTokinSource - ctx.TryReset.
Thread.ManagedThreadID and Thread.UnsafeStart- not supported

10. Delegate Task vs Promise Task (.NET).

11. .NET Promise task is the same than Promise in JS.

12. Delegate Task vs Promise Task Article.Read more about difference...

Article contains description of:

Wait/WaitAll/WaitAny
GetAwaiter().GetResult()/await
ContinueWith/TaskFactory.ContinueWhenAny/TaskFactory.ContinueWhenAll/Task.WhenAll/Task.WhenAny

In the TPL world the various Delegate Tasks are divided up among different threads, which then actually execute the code in those Delegate Tasks. Read more

TaskFactory.StartNew
CancellationToken
TaskCreationOptions
TaskScheduler
Task.Run (shortcut of Task.Factory.StartNew)

In the async world, most tasks are Promise Tasks. When code does an await on a Promise Task, there is no thread tied up waiting for that task to complete. read more No thread mean there is only kernel callback.