.NET Parallel Programming

All about Async/Await, System.Threading.Tasks, System.Collections.Concurrent, System.Linq, and more…

.NET 4.5 - .NET Parallel Programming

Awaiting Socket Operations

December 15, 2011 Dec 15, 2011 12/15/11
Stephen Toub - MSFT
The System.Net.Sockets.Socket class in .NET exposes multiple sets of asynchronous methods that perform the same basic operations but that are exposed with different patterns.The first set follows the APM pattern, where for a synchronous method like Receive, the BeginReceive and EndReceive methods are exposed.  If you want to be able to &...

Coalescing CancellationTokens from Timeouts

December 3, 2011 Dec 3, 2011 12/3/11
Stephen Toub - MSFT
In the .NET Framework 4.5 Developer Preview, you’ll find that CancellationTokenSource now has timeout support built directly into its implementation.  This makes it very easy to create a token that will automatically have cancellation requested after a particular time interval, e.g. public static CancellationToken FromTimeout(int ...

PLINQ Queries That Run in Parallel in .NET 4.5

November 10, 2011 Nov 10, 2011 11/10/11
Igor Ostrovsky - MSFT
One interesting thing to know about PLINQ is that not all queries are guaranteed to execute in parallel (See PLINQ Queries That Run Sequentially for reference). You can think of the AsParallel method as a hint to run in parallel for query shapes that it believes will be faster. By default, PLINQ prefers to use a simple sequential algorithm ...

Crafting a Task.TimeoutAfter Method

November 10, 2011 Nov 10, 2011 11/10/11
Joe Hoag
Imagine that you have a Task handed to you by a third party, and that you would like to force this Task to complete within a specified time period. However, you cannot alter the “natural” completion path and completion state of the Task, as that may cause problems with other consumers of the Task. So you need a way to obtain a copy or “...

Exception Handling in TPL Dataflow Networks

November 9, 2011 Nov 9, 2011 11/9/11
Cristina Manu
A “dataflow block” is represented by a class implementing the IDataflowBlock interface. The state of a dataflow block is represented by the state of its IDataflowBlock.Completion Task, which itself has a Status property. When a dataflow block is in active state, meaning that it is currently doing processing or may do more processing in the...

ConcurrentDictionary Performance Improvements in .NET 4.5

November 8, 2011 Nov 8, 2011 11/8/11
Igor Ostrovsky - MSFT
ConcurrentDictionary is a popular concurrent data structure that was introduced in .NET 4. In the .NET 4.5 release, ConcurrentDictionary gets two performance improvements. One optimization is related to the way ConcurrentDictionary avoids torn reads and writes. To explain the background, all reference types and some value types are guaranteed...

When at last you await

October 24, 2011 Oct 24, 2011 10/24/11
Stephen Toub - MSFT
When you start using async methods heavily, you’ll likely see a particular pattern of composition pop up from time to time.  Its structure is typically either of the form: async Task FooAsync() {     … // some initialization code without awaits      await BarAsync(&hellip...