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

Logging in Haskell


A final thing we'll consider is more related to I/O than streaming: logging in Haskell applications. Logging is important in any sufficiently important application.

In a small scale, a list- or DList-based WriterT monad is often all that is needed: it's simple and potentially pure (if the underlying monad is pure). However, on a bigger scale it doesn't make sense to store messages in an internal pure data structure. Instead, it's most efficient to write them to disk (or over a network) immediately (likely still using a buffer, though).

Furthermore, it would be nice if the logging functionality could be decoupled from other application code, even reused between different applications.

A popular solution which provides just that kind of decoupling is the monad-logger library. It uses a library called Fastlogger, which provides logging that scales in multicore environments. Most notoriously, FastLogger is used in the Web Application Interface (WAI) package used by many high...