CppCon 2018

We often write programs in such a way as to make them run fast. We want good average speed, high throughput, and we tend to be happy when benchmarks show that our peak running speed is better than expected.

However, it's sometimes useful to write programs where we want to make the worst-case scenario faster, or make it run at predictable speed, or even reduce variations in execution speed. Instead of concentrating our efforts on making the best or the average speed better, we sometimes need to make the worst case speed "less bad".

C++ is a wonderful language for such situations. C++ gives us a lot of control over what's going on, and we can use this control to our advantage.

The aim of this talk is to discuss techniques to make the execution speed of programs more predictable, and to guide the compiler towards generating code where worst-case execution speed respects some constraints. It will probably most interesting to intermediate audiences who are curious about how to address such issues, or who wonder why it is sometimes important to be pessimistic and worry about those times when program execution takes the slow path.