We often think of performance testing as one of those things we just have to do at the end of a project, often using heavyweight tool sets in dedicated environments. In this talk, James offers an alternative. What decisions would we make differently if we had the ability to rapidly perform experiments using lightweight performance tests? The tools and techniques we now have available makes a new type of architectural decision making possible; from Software Defined Networking, IaaS and Continuous Delivery to Real Options and Architecture Decision Records.James will cover pre-requisites that allow us to make small bets on performance and explore the strange world of evolutionary design that this technique makes possible.