.NET Parallel Programming

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

Task Parallel Library - .NET Parallel Programming

Is it ok to use nested Parallel.For loops?

March 14, 2012 Mar 14, 2012 03/14/12
Stephen Toub - MSFT
Every now and then, I get this question: “is it ok to use nested Parallel.For loops?” The short answer is “yes.”  As is often the case, the longer answer is, well, longer. Typically when folks ask this question, they’re concerned about one of two things.  First, they’re concerned that each nested loop will assume it “...

Are you using TPL Dataflow? We’d love to know!

March 6, 2012 Mar 6, 2012 03/6/12
Stephen Toub - MSFT
Are you using the new System.Threading.Tasks.Dataflow.dll library, either from its CTPs or from the .NET 4.5 Developer Preview or Beta?  We'd love to hear about it, and if you have time, what your experiences have been (good or bad).  What kind of solution are you building, and how are you using TPL Dataflow in it?  Has the ...

Implementing a simple ForEachAsync, part 2

March 5, 2012 Mar 5, 2012 03/5/12
Stephen Toub - MSFT
After my previous post, I received several emails and comments from folks asking why I chose to implement ForEachAsync the way I did.  My goal with that post wasn’t to prescribe a particular approach to iteration, but rather to answer a question I’d received… obviously, however, I didn’t provide enough background...

Implementing a simple ForEachAsync

March 4, 2012 Mar 4, 2012 03/4/12
Stephen Toub - MSFT
Jon Skeet recently asked me how I might go about implementing the following “asynchronous ForEach” behavior: For each element in an enumerable, run a function that returns a Task<TResult> to represent the completion of processing that element. All of these functions may run asynchronously concurrently. As each task ...

What’s New for Parallelism in .NET 4.5 Beta

February 29, 2012 Feb 29, 2012 02/29/12
Stephen Toub - MSFT
At //BUILD/ in September, we blogged about the wealth of new support available for parallelism in the .NET Framework 4.5 Developer Preview.  Since then, we’ve been hard at work on the .NET 4.5 Beta.  With the beta just released, here are a few interesting and related things that are new or have changed since the Developer ...

Building Async Coordination Primitives, Part 7: AsyncReaderWriterLock

February 12, 2012 Feb 12, 2012 02/12/12
Stephen Toub - MSFT
In my last past, we looked at building an AsyncLock in terms of an AsyncSemaphore.  In this post, we’ll build a more advanced construct, an asynchronous reader/writer lock.An asynchronous reader/writer lock is more complicated than any of the previous coordination primitives we’ve created.  It also involves more policy, ...

Building Async Coordination Primitives, Part 6: AsyncLock

February 12, 2012 Feb 12, 2012 02/12/12
Stephen Toub - MSFT
Last time, we looked at building an AsyncSemaphore.  Here, we’ll look at building support for an async mutual exclusion mechanism that supports scoping via ‘using’.As mentioned in the previous post, semaphores are great for throttling and resource management.  You can give a semaphore an initial count of the number ...

Building Async Coordination Primitives, Part 5: AsyncSemaphore

February 12, 2012 Feb 12, 2012 02/12/12
Stephen Toub - MSFT
In my last few posts, I covered building an AsyncManualResetEvent, an AsyncAutoResetEvent, an AsyncCountdownEvent, and an AsyncBarrier.  In this post, I’ll cover building an AsyncSemaphore class.Semaphores have a wide range of applicability.  They’re great for throttling, for protected access to a limited set of resources...

Building Async Coordination Primitives, Part 4: AsyncBarrier

February 11, 2012 Feb 11, 2012 02/11/12
Stephen Toub - MSFT
Last time, we looked at building an AsyncCountdownEvent.  At the end of the post, I highlighted a common pattern for using such a type, which is for all of the participants to signal and then wait for all of the other participants to signal as well.  This kind of synchronization is typically referred to as a “barrier,” ...