Software Architect's Handbook

Performance is a requirement

Speed is a feature of your application and if it is not fast enough, then it is not good enough. Performance is a quality attribute of software systems and cannot be considered as just an afterthought. It should play an integral part throughout the life cycle of a software application. It is a requirement of the system and, like other requirements, it must be unambiguous, measurable, and testable.

When we discussed requirements in Chapter 3, Understanding the Domain, it was stated that requirements must be specified clearly, measurable with specific values/limits when appropriate, and testable so that it can be determined whether the requirement has been satisfied. For example, it is not sufficient to simply state ...