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

Profiling


We’ve briefly discussed profiler types in Chapter 1, Performance by Design. The JVisualVM tool we discussed with respect to introspection in the previous section is also a CPU and memory profiler that comes bundled with the JDK. Let us see them in action. Consider the following two Clojure functions that stress on the CPU and memory respectively:

(defn cpu-work []
  (reduce + (range 100000000)))

(defn mem-work []
  (->> (range 1000000)
       (map str)
       vec
       (map keyword)
       count))

Using JVisualVM is pretty easy; open the Clojure JVM process from the left-pane. It has the sampler and regular profiler styles for profiling. Start profiling for CPU or memory use when the code is running and wait for it to collect enough data to plot on the screen. The following screenshot shows CPU profiling in action:

The following screenshot shows memory profiling in action:

JVisualVM is a very simple, entry-level profiler. There are several commercial JVM profilers on the market...