Book Image

The Art of Writing Efficient Programs

By : Fedor G. Pikus
3 (2)
Book Image

The Art of Writing Efficient Programs

3 (2)
By: Fedor G. Pikus

Overview of this book

The great free lunch of "performance taking care of itself" is over. Until recently, programs got faster by themselves as CPUs were upgraded, but that doesn't happen anymore. The clock frequency of new processors has almost peaked, and while new architectures provide small improvements to existing programs, this only helps slightly. To write efficient software, you now have to know how to program by making good use of the available computing resources, and this book will teach you how to do that. The Art of Efficient Programming covers all the major aspects of writing efficient programs, such as using CPU resources and memory efficiently, avoiding unnecessary computations, measuring performance, and how to put concurrency and multithreading to good use. You'll also learn about compiler optimizations and how to use the programming language (C++) more efficiently. Finally, you'll understand how design decisions impact performance. By the end of this book, you'll not only have enough knowledge of processors and compilers to write efficient programs, but you'll also be able to understand which techniques to use and what to measure while improving performance. At its core, this book is about learning how to learn.
Table of Contents (18 chapters)
1
Section 1 – Performance Fundamentals
7
Section 2 – Advanced Concurrency
11
Section 3 – Designing and Coding High-Performance Programs

Summary

In this chapter, we have learned how the memory system works: in a word, slowly. The difference in the performance of the CPUs and the memory creates the memory gap, where the fast CPU is held back by the low performance of the memory. But the memory gap also contains within it the seeds of the potential solution: we can trade many CPU operations for one memory access.

We have further learned that the memory system is very complex and hierarchical and that it does not have a single speed. This can hurt your program's performance really badly if you end up in the worst-case scenario. But again, the trick is to look at it as an opportunity rather than a burden: the gains from optimizing memory accesses can be so large that they more than pay for the overhead.

As we have seen, the hardware itself provides several tools to improve memory performance. Beyond that, we have to choose memory-efficient data structures and, if that alone does not suffice, memory-efficient...