Available since .NET 4, ThreadLocal<T> is a container that holds a separate value for every thread. In practice, ThreadLocal<T> is often convenient for storing per-thread counters, resources, or partial results. As mentioned earlier on this blog, we have been thinking about adding a Values property to enumerate over the values from all...
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 to b...
.NET 4 and Visual Studio 2010 saw the introduction of a wide range of new support for parallelism: the Task Parallel Library (TPL), Parallel LINQ (PLINQ), new synchronization and coordination primitives and collections (e.g. ConcurrentDictionary), an improved ThreadPool for handling parallel workloads, new debugger windows, new concurrency visualiz...
Sorting is one of the most fundamental problems in software algorithms; there are many sequential sorting algorithms with different time and memory complexities, but when it comes to parallel sort, things get more complicated. I will explain a simple and scalable algorithm to write a parallel sort using the .NET 4.0 System.Threading.Barrier synchro...
ConcurrentDictionary<TKey,TValue>, first introduced in .NET 4, is an efficient dictionary data structure that enables thread-safe reading and writing, meaning that multiple threads may all be accessing the dictionary at the same time without corrupting it. It supports adding through its TryAdd method, conditional updates through its Try...
One of the hidden gems in .NET 4 is the System.Threading.SpinWait type. This type is typically used for implementing lock-free solutions, and is used heavily throughout the rest of the threading and parallelism support in .NET 4. That’s why I call it “hidden”, because most folks don’t implement their own lock-fre...
We’ve been considering adding a Values property to System.Threading.ThreadLocal<T>. Values would return a collection of all current values from all threads (e.g. what you’d get if you evaluated Value from each thread). This would allow for easy aggregations, and in fact in our Parallel Extensions Extras we have a wrapp...
The .NET Framework 4 introduces a new mechanism for cancellation of operations, based on new types CancellationToken and CancellationTokenSource. This cancellation mechanism is used across the parallel programming libraries: tasks, concurrent collections, and PLINQ queries.Using Cancellation Support in .NET Framework 4, written by Mike Li...
We’ve been very excited about the new debugging windows in Visual Studio 2010, namely Parallel Tasks and Parallel Stacks, as well as the newly revamped Threads window, and thus we’ve talked about them quite a bit. For an overview, you can read the MSDN Magazine article at https://msdn.microsoft.com/en-us/magazine/ee410778.aspx, and Daniel Moth has ...
(The full set of ParallelExtensionsExtras Tour posts is available here.) In a previous ParallelExtensionsExtras Tour blog post, we talked about implementing a custom partitioner for BlockingCollection<T>. Custom partitioning is an advanced but important feature supported by both Parallel.ForEach and PLINQ, as it allows the develope...
