.NET Parallel Programming

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

New Task APIs in .NET 4.6

February 2, 2015 Feb 2, 2015 02/2/15
Stephen Toub - MSFT
There are several nice API-level enhancements to the Task Parallel Library in .NET 4.6, which you can grab a preview of as part of the Visual Studio 2015 CTP. Task.From* .NET 4.5 had a Task.FromResult method.  This method makes it quick and easy to manufacture a new Task for a known result value, and is particularly useful when ...

.NET memory allocation profiling and Tasks

April 4, 2013 Apr 4, 2013 04/4/13
Stephen Toub - MSFT
The .NET Framework blog published this morning a guest post from yours truly on .NET Memory Allocation Profiling with Visual Studio 2012.  As you're trying to improve the performance, throughput, and memory usage of code that uses Tasks, the described profiler in Visual Studio can be a valuable tool in your tool belt (of course, the ...

Tasks, Monads, and LINQ

April 3, 2013 Apr 3, 2013 04/3/13
Stephen Toub - MSFT
A few years back, Wes Dyer wrote a great post on monads, and more recently, Eric Lippert wrote a terrific blog series exploring monads and C#. In that series, Eric alluded to Task<TResult> several times, so I thought I’d share a few related thoughts on Task<TResult> and the async/await keywords.As both Wes and Eric highlight...

“Invoke the method with await”… ugh!

March 13, 2013 Mar 13, 2013 03/13/13
Stephen Toub - MSFT
I can be a bit sensitive when it comes to language and how concepts are conveyed.  I think it’s important to be accurate, even if not precise, when describing what something is or how to use it, as otherwise the folks to whom you’re communicating can easily form the wrong mental model for that thing.  Having a good mental...

MVP Summit presentation on async

February 20, 2013 Feb 20, 2013 02/20/13
Stephen Toub - MSFT
Lucian Wischik and I presented an "async clinic" at the MVP Summit in Bellevue this week.  The async/await keywords in C# and Visual Basic drastically simplify asynchronous programming, but that of course doesn't mean that using them is without any gotchas: the goal of the discussion was to highlight some of the key areas in ...

Psychic Debugging of Async Methods

January 28, 2013 Jan 28, 2013 01/28/13
Stephen Toub - MSFT
These days it’s not uncommon for me to receive an email or read a forum post from someone concerned about a problem they’re experiencing with an async method they’ve written, and they’re seeking help debugging the issue.  Sometimes plenty of information about the bug is conveyed, but other times the communication ...

Cooperatively pausing async methods

January 13, 2013 Jan 13, 2013 01/13/13
Stephen Toub - MSFT
Recently I was writing an app that processed a bunch of files asynchronously.  As with the Windows copy file dialog, I wanted to be able to provide the user with a button that would pause the processing operation.To achieve that, I implemented a simple mechanism that would allow me to pass a “pause token” into the async method...

C# memory model articles

December 14, 2012 Dec 14, 2012 12/14/12
Stephen Toub - MSFT
Igor Ostrovsky is one of the minds behind the parallel programming support in the .NET Framework.  Igor's recently written a great set of articles for MSDN Magazine to cover "The C# Memory Model in Theory and Practice".  Part 1 is available now in the December 2012 issue, and it's a great read...

PLINQ and Int32.MaxValue

November 16, 2012 Nov 16, 2012 11/16/12
Stephen Toub - MSFT
In both .NET 4 and .NET 4.5, PLINQ supports enumerables with up to Int32.MaxValue elements.  Beyond that limit, PLINQ will throw an overflow exception.  LINQ to Objects itself has this limitation with certain query operators (such as the indexed Select operator which counts the elements processed), but PLINQ has it with more.This ...