Book Image

Haskell High Performance Programming

By : Samuli Thomasson
Book Image

Haskell High Performance Programming

By: Samuli Thomasson

Overview of this book

Haskell, with its power to optimize the code and its high performance, is a natural candidate for high performance programming. It is especially well suited to stacking abstractions high with a relatively low performance cost. This book addresses the challenges of writing efficient code with lazy evaluation and techniques often used to optimize the performance of Haskell programs. We open with an in-depth look at the evaluation of Haskell expressions and discuss optimization and benchmarking. You will learn to use parallelism and we'll explore the concept of streaming. We’ll demonstrate the benefits of running multithreaded and concurrent applications. Next we’ll guide you through various profiling tools that will help you identify performance issues in your program. We’ll end our journey by looking at GPGPU, Cloud and Functional Reactive Programming in Haskell. At the very end there is a catalogue of robust library recommendations with code samples. By the end of the book, you will be able to boost the performance of any app and prepare it to stand up to real-world punishment.
Table of Contents (21 chapters)
Haskell High Performance Programming
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Summary


We started this chapter by profiling programs by cost centres, which can be set automatically (-fprof-auto) or manually (SCC-annotations). We learned that there is overhead in profiling, which is why execution times are an inaccurate metric when profiling. Allocations remained a good measure of performance in any case. We used the heap profiler to produce informative graphs about memory usage over time, and to spot unwanted allocations and retainers.

We explored different options in the GHC heap profiler: break-downs and subset selections, both of which draw more or less from the same pool of parameters. The default break-down was by cost not yet finished.

Finally, we looked at two additional libraries, criterion for benchmarking and ekg for monitoring. In discussing criterion, we stumbled upon the concept of normal form, which will also come up later on when we discuss parallelism. Adding real-time graphical garbage garbage collector monitoring via HTTP to a Haskell application was...