Book Image

Clojure High Performance Programming

By : Shantanu Kumar
Book Image

Clojure High Performance Programming

By: Shantanu Kumar

Overview of this book

<p>Clojure is a young, dynamic, functional programming language that runs on the Java Virtual Machine. It is built with performance, pragmatism, and simplicity in mind. Like most general purpose languages, Clojure’s features have different performance characteristics that one should know in order to write high performance code.<br /><br />Clojure High Performance Programming is a practical, to-the-point guide that shows you how to evaluate the performance implications of different Clojure abstractions, learn about their underpinnings, and apply the right approach for optimum performance in real-world programs.<br /><br />This book discusses the Clojure language in the light of performance factors that you can exploit in your own code.</p> <p>You will also learn about hardware and JVM internals that also impact Clojure’s performance. Key features include performance vocabulary, performance analysis, optimization techniques, and how to apply these to your programs. You will also find detailed information on Clojure's concurrency, state-management, and parallelization primitives.</p> <p>This book is your key to writing high performance Clojure code using the right abstraction, in the right place, using the right technique.</p>
Table of Contents (15 chapters)
Clojure High Performance Programming
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Precomputing and caching


While processing data, we usually come across instances where a few common computation steps precede several kinds of subsequent steps. That is to say some amount of computation is common and the remaining is different. For high latency common computations (I/O to access the data and memory/CPU to process it), it makes a lot of sense to compute them once and then store them in a digest form. Then, the subsequent steps can simply use the digest data and proceed from that point onwards, thus resulting in reduced overall latency. This is also known as staging of semi-computed data, and it is a common technique to optimize processing of nontrivial amount of data.

Clojure has decent support for caching. The built-in clojure.core/memoize function perform basic caching of computed results with no flexibility in using specific caching strategies and pluggable backends. The Clojure Contrib library core.memoize (https://github.com/clojure/core.memoize) offsets the lack of flexibility...