.NET Parallel Programming

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

Parallel Extensions - .NET Parallel Programming

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...

Task.Run vs Task.Factory.StartNew

October 24, 2011 Oct 24, 2011 10/24/11
Stephen Toub - MSFT
In .NET 4, Task.Factory.StartNew was the primary method for scheduling a new task.  Many overloads provided for a highly configurable mechanism, enabling setting options, passing in arbitrary state, enabling cancellation, and even controlling scheduling behaviors.  The flip side of all of this power is complexity.  You need to ...

Keeping Async Methods Alive

October 2, 2011 Oct 2, 2011 10/2/11
Stephen Toub - MSFT
Consider a type that will print out a message when it’s finalized, and that has a Dispose method which will suppress finalization: class DisplayOnFinalize : IDisposable {     public void Dispose() { GC.SuppressFinalize(this); }     ~DisplayOnFinalize() { Console.WriteLine(“Finalized”); } } Now ...

Don’t Forget To Complete Your Tasks

October 2, 2011 Oct 2, 2011 10/2/11
Stephen Toub - MSFT
“Don’t forget to complete your tasks.”  That guidance may sound trivial and silly, but I recently saw it as a source of a bug in software written by some very smart folks, and thus thought this would be a good opportunity to remind folks of the imperative.Tasks represent a promise.  If you hand one out, someone else...

Task Exception Handling in .NET 4.5

September 28, 2011 Sep 28, 2011 09/28/11
Stephen Toub - MSFT
For the .NET Framework 4.5 Developer Preview, a lot of work has been done to improve the Task Parallel Library (TPL), in terms of functionality, in terms of performance, and in terms of integration with the rest of the .NET Framework.  With all of this work, we’ve strived for a very high compatibility bar, which means your ...

Updated TPL Dataflow CTP

September 27, 2011 Sep 27, 2011 09/27/11
Stephen Toub - MSFT
It’s been a few months since April when we last released a Community Technology Preview (CTP) of System.Threading.Tasks.Dataflow.dll, aka “TPL Dataflow”.  Today for your programming pleasure, we have another update.As mentioned in “What’s New for Parallelism in .NET 4.5”, System.Threading.Tasks.Dataflow...