Book Image

.NET 4.5 Parallel Extensions Cookbook

By : Bryan Freeman
Book Image

.NET 4.5 Parallel Extensions Cookbook

By: Bryan Freeman

Overview of this book

<p>.NET parallel extensions brings the power of parallel and asynchronous programming to a much wider developer audience than ever before. This book will give a developer with no multithreaded development experience the ability to write highly scalable parallel applications that take advantage of modern multicore processors.If you are an experienced .NET developer who wants to put parallel extensions to work in your applications, this book is for you.</p> <p>".NET 4.5 Parallel Extensions Cookbook" is a practical, hands-on guide that provides you with a number of clear step-by-step recipes that will introduce parallelism into your applications and take advantage of modern multicore processors. This book is a crash course in using the extensions, with theory and concepts kept to a minimum.</p> <p>".NET 4.5 Parallel Extensions Cookbook" offers a wide-ranging presentation of parallel development concepts, and provides a working knowledge of key technologies that are important to developers who want to take advantage of multi-core architectures.</p> <p>You will learn how to compose a series of producer/consumer tasks into a pipeline that can process data elements received from a real-time event stream. You will also learn how to connect the stages of pipelines together using the concurrent collections. You will learn everything you need to know to transform the multicore power found in modern processors into application performance and scalability.</p>
Table of Contents (16 chapters)
.NET 4.5 Parallel Extensions Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Forcing parallel execution


Parallel LINQ looks for opportunities to parallelize a query, but not all queries run faster in parallel. For example, a query that contains a single delegate that does only a little bit of work will usually run faster sequentially, because the overhead of parallelizing outweighs the benefits gained from parallelizing it.

For the most part, parallel LINQ does a really good job of determining what should be parallelized and what should run sequentially, based on its examination of the shape of the query. However, the algorithm it uses is not perfect, and you might need to instruct PLINQ to run your query in parallel.

In this recipe, we will build a Console application that creates a query which PLINQ will determine whether it needs to be executed sequentially. We will then force the query to run in parallel using the WithExecutionMode method. Finally, we will capture the time it takes for both queries to run and compare the results.

How to do it…

Now, let's see how...