.NET Parallel Programming

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

February 2012 - .NET Parallel Programming

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,” ...

Building Async Coordination Primitives, Part 3: AsyncCountdownEvent

February 11, 2012 Feb 11, 2012 02/11/12
Stephen Toub - MSFT
In my last two posts, I discussed building AsyncManualResetEvent and AsyncAutoResetEvent coordination primitives.  In this post, I’ll build on that to create a simple AsyncCountdownEvent.A countdown event is an event that will allow waiters to complete after receiving a particular number of signals.  The “countdown&rdquo...

Building Async Coordination Primitives, Part 2: AsyncAutoResetEvent

February 11, 2012 Feb 11, 2012 02/11/12
Stephen Toub - MSFT
In my last post, I discussed building an asynchronous version of a manual-reset event.  This time, we’ll build an asynchronous version of an auto-reset event.A manual-reset event is transitioned to the signaled state when requested to do so (i.e. calling Set()), and then it remains in that state until it’s manually ...

Building Async Coordination Primitives, Part 1: AsyncManualResetEvent

February 11, 2012 Feb 11, 2012 02/11/12
Stephen Toub - MSFT
The Task-based Async Pattern (TAP) isn’t just about asynchronous operations that you initiate and then asynchronously wait for to complete.  More generally, tasks can be used to represent all sorts of happenings, enabling you to await for any matter of condition to occur.  We can even use Tasks to build simple coordination ...

Potential pitfalls to avoid when passing around async lambdas

February 8, 2012 Feb 8, 2012 02/8/12
Stephen Toub - MSFT
One of the really useful capabilities of the new async methods feature in C# and Visual Basic is the ability to write async lambdas and anonymous methods (from here on in this post, I’ll refer to both of these as async lambdas, since the discussion applies equally to both).  This allows you to easily get a delegate to represent an ...

When “ExecuteSynchronously” doesn’t execute synchronously

February 7, 2012 Feb 7, 2012 02/7/12
Stephen Toub - MSFT
When creating a task continuation with ContinueWith, developers have the opportunity to provide a TaskContinuationOptions enum value, which could include the TaskContinuationOptions.ExecuteSynchronously flag.  ExecuteSynchronously is a request for an optimization to run the continuation task on the same thread that completed the ...