.NET Parallel Programming

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

Cancellation in Parallel Extensions

One of the great features that crosses all of Parallel Extensions types is a consistent approach to cancellation (see https://blogs.msdn.com/pfxteam/archive/2009/05/22/9635790.aspx). In this post we explore some of the ways cancellation is used in Parallel Extensions and explain the guidance we developed. The new cancellation system is a ...

Tasks and the APM Pattern

The Asynchronous Programming Model (APM) in the .NET Framework has been around since .NET 1.0 and is the most common pattern for asynchrony in the Framework.  Even if you’re not familiar with the name, you’re likely familiar with the core of the pattern.  For a given synchronous operation Xyz, the asynchronous version ...

Mechanisms for Creating Tasks

The core entity in the Task Parallel Library around which everything else revolves is System.Threading.Tasks.Task.  The most common way of creating a Task will be through the StartNew method on the TaskFactory class, a default instance of which is exposed through a static property on Task, e.g. var t = Task.Factory.StartNew(() => { &...

Tasks and Unhandled Exceptions

Prior to the .NET Framework 2.0, unhandled exceptions were largely ignored by the runtime.  For example, if a work item queued to the ThreadPool threw an exception that went unhandled by that work item, the ThreadPool would eat that exception and continue on its merry way.  Similarly, if a finalizer running on the finalizer thread ...

ParallelOptions.MaxDegreeOfParallelism vs PLINQ’s WithDegreeOfParallelism

We exert a good deal of effort ensuring that the APIs we provide are consistent within Parallel Extensions as well as with the rest of the .NET Framework.  This is from many angles, including behavior and general design, but also naming.  So when there are slight differences in naming, it raises questions.One occurrence of such a ...