When to start Performance Testing?
While, it is ideal to start performance testing as soon as there is a confidence in stability of the system under test; that shouldn't be an entry criteria always. With that being said, doing performance testing after achieving the desired stability will keep the testing outcome clear and precise. In case of modern, distributed systems; doing performance testing at independent component level shall be right thing to do. For example: Backend can be tested for its overall response/latency measurement and GUI can be test doubled and verified for its overall responsiveness under various conditions, which you can create in your test environment (Ex. high latency network links, slow responding backend under certain load conditions etc.). This strategy shall give you the performance assessment at individual unit level and its good to know baseline & benchmark of each of the component. So when you run end-2-end performance tests after integration, identifying bottlenecks could be relat...