Dev Blogs
One of the ways in which the Task Parallel Library achieves good performance is through “work-stealing”. Work-stealing is supported in the .NET 4 ThreadPool for access through the Task Parallel Library and its default scheduler. This manifests as every thread in the ThreadPool having its own queue for work; when that thread ...
In many data-parallel scenarios, all of the data to be processed is available immediately. This blog post addresses the opposite scenario: the inputs arrive gradually (as if in a stream), and we want to start producing results even before reading the last element of the input sequence. There is a variety of scenarios in which inputs become ava...
More and more, developers are realizing the significant scalability advantages that asynchronous programming can provide, especially as it relates to I/O. Consider an application that needs to copy data from one stream to another stream, such as is being done in the following synchronous implementation: static void CopyStreamToStream(Stream input...
In concurrent programs, race conditions are a fact of life but they aren’t all bad. Sometimes, race conditions are benign, as is often the case with lazy initialization. The problem with racing to set a value, however, is that it can result in multiple objects being instantiated when only one is needed. Take the LazyInitializer ...
In a previous post, it was demonstrated how for loops with very small loop bodies could be parallelized by creating an iterator over ranges, and then using Parallel.ForEach over those ranges. A similar technique can be used to write parallel loops over iteration spaces of non-integers. For example, let’s say I wanted to paralleliz...
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 cooperativ...
As has been discussed previously, one of the new features in the Task Parallel Library is TaskCompletionSource<TResult>, which enables the creation of a Task<TResult> that represents any other asynchronous operation. There are a wide variety of sources in the .NET Framework for asynchronous work. One comes from components th...
As Ed Essey explained in Partitioning in PLINQ, partitioning is an important step in PLINQ execution. Partitioning splits up a single input sequence into multiple sequences that can be processed in parallel. This post further explains chunk partitioning, the most general partitioning scheme that works on any IEnumerable<T>.Chunk partitioning ...
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 manifest...
The Parallel class represents a significant advancement in parallelizing managed loops. For many common scenarios, it just works, resulting in terrific speedups. However, while ideally Parallel.For could be all things to all people, such things rarely work out, and we’ve had to prioritize certain scenarios over others.One area Par...