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

Understanding threads and concurrency

All high-performance computers today have multiple CPUs or multiple CPU cores (independent processors in a single package). Even most laptop computers have at least two, often four, cores. As we have said many times, in the context of performance, efficiency is not leaving any hardware idle; a program cannot be efficient or high-performing if it uses only a fraction of the computing power, such as one of many CPU cores. There is only one way for a program to use more than one processor at a time: we have to run multiple threads or processes. As a side note, this isn't the only way to use multiple processors for the benefit of the user: very few laptops, for example, are used for high-performance computing. Instead, they use multiple CPUs to better run different and independent programs at the same time. It is a perfectly good use model, just not the one we are interested in in the context of high-performance computing. HPC systems usually...