Summary

What should we understand from all of this? To produce software that operates at the edge of the machine's ability, you must understand some important things. Firstly, if you aren't measuring your program, you're only guessing. Measuring runtime, as criterion does, is important but a coarse insight. Where is my program spending its time? is a question the Valgrind suite and perf can answer, but you've got to have benchmarks in place to contextualize your questions. Measuring and then validating behavior is also an important chunk of this work, which is why we spent so much time on QuickCheck and AFL. Secondly, have a goal in mind. In this chapter, we've made the speed of standard library HashMap our goal but, in an actual code base, there's always going to be places to polish and improve. What matters is knowing what needs to happen to...