What is the difference between Performance Testing and Performance Engineering?

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Accepted Answer

Classic performance testing is effectively a subset of performance engineering. It usually entails running a single round of load testing as part of the post-development quality assurance (QA) cycle. Performance testing involves checking the speed, reliability, scalability, stability, response time, and resource use of an application under the anticipated workload. Before we get into the differences between performance engineering and performance testing, we’ll first take a look at performance testing in isolation and why it’s, by itself, no longer sustainable. First, the testing is viewed in isolation and treated as an afterthought that only begins at the end of functional testing. Second, working in silos causes large communication gaps between project sub-teams and prevents the collaboration required to deliver a high quality product. Third, by the time performance testing kicks in, the organization has already sunk substantial time, effort, and finances into the application’s design, development, and promotion. Fourth, performance testing is often treated as an afterthought and isn’t included in the ‘done’ criteria preceding release. So at this juncture, the business needs the app in production urgently and expects no delays. In this context, QA's feedback happens too late to fix completely before the release. Inevitably, a high number of performance problems would unnecessarily make it to the production environment just so the release remained within schedule. Fixing a defect in production is much more expensive and disruptive than doing so early in development. Fifth, traditional performance testing may have been perfect for the Waterfall model but is out of place in today’s DevOps-centric world. DevOps reduces the failure rate of new releases by shrinking the time between when a change is committed to the system and when the change is placed in production. Continuous integration and continuous delivery (CI/CD) makes sure the software is always in a releasable state throughout its lifecycle. DevOps also focuses on realigning the organization to support end-to-end collaboration between stakeholders, functions and tools. To meet the rapid delivery demands of DevOps, software development needs a more evolved performance testing approach. That new approach is software performance engineering. Now, let’s delve into the key differences between performance engineering vs. performance testing. First, performance testing is a quality check of the application’s load handling and responsiveness. It establishes how well the system will bear a production load and anticipates the issues that could come up during heavy load conditions. Performance engineering seeks to design the application from the start with performance metrics in mind and facilitate the discovery of issues early in development. Second, performance testing is a QA process that usually takes place when a round of software development is complete. Performance engineering is a continuous process that is embedded in all phases of the software development cycle – from design, to development, and into the end-user experience. Third, performance testing is conducted by the QA team while performance engineering involves RND and QA.