Introduction

After providing the theory on the memory model and the multithreading interface, I will now apply the theory in practice and provide you a few performance numbers.

$$$$

Calculating the Sum of a Vector

What is the fastest way to add the elements of a std::vector? To get the answer, I will fill a std::vector with one hundred million arbitrary but uniformly distributed numbers between 1 and 10. The task is to calculate the sum of the numbers in various ways; I use the performance of a single threaded addition as the reference execution time. In this chapter, I will also discuss atomics, locks, thread local data, and tasks.

Let’s start with the single-threaded scenario in the next lesson.