It's quite well-known today that F# has been a first class citizen, a built-in part of programming language support in Visual Studio, starting from Visual Studio 2010. F# is a programming language that has its own unique trait: it is a functional programming language and at the same time it has object-oriented programming (OOP) support. F# from the start has run on .NET, although we can also run F# on cross-platform, such as Android (using Mono).
Although F# mostly runs faster than C# or VB when doing computations, its own performance characteristics and some not so obvious bad practices and subtleties may have led to performance bottlenecks. The bottlenecks may or may not be faster than the C#/VB counterparts, although some of the bottlenecks may share the same performance characteristics, such as the use of .NET APIs. The main goal of this book is to identify performance problems in F#, measuring and also optimizing F# code to run more efficiently, while also maintaining the functional programming style as appropriately as possible.
Note
A basic knowledge of F# (including the functional programming concept and basic OOP) is required as a prerequisite to start understanding the performance problems and the optimization of F#.
There are many ways to define F# performance characteristics and at the same time to measure them, but understanding the mechanics of running F# code, especially on top of .NET, is crucial and is also a part of the performance characteristics itself. This includes other aspects of approaches to identify concurrency problems and language constructs. This chapter describes the optimization of F# code and will cover the following topics:
Understanding the nature of F# code
Overview of common bottlenecks
Commonly misunderstood concurrency problems
Overview of tooling in .NET including Visual Studio to help understanding the running code
Immediate testing of F# code in F# interactive
Introduction to debugging in F#