- [[Performance Testing]] is part of [[Performance Engineering]]. - When we're testing, we are looking to prove or disprove our hypothesis about an application's performance. This hypothesis is usually informed by the test [[Requirements]]; in other words, we are attempting to answer questions we've been told to ask. - Performance **engineering** is about knowing which questions to ask, and when. It's a broader area of expertise and requires more hands-on experience. - "`Within minutes I was telling the QA manager that his application would fail under load and that response times would not pass his service-level objective. I didn't need to run a test because I knew what to expect, having tested many applications like this one in the past. But they were skeptical as I confidently told them—without any test results to back me up—that the application needed some fundamental architectural changes. `" - "`The main difference between an engineer and a tester is that an engineer does not need to run a test to diagnose or assist in correcting a performance issue. (For a more in-depth discussion of the differences, listen to my podcast discussion with Perfbytes Podcast host James Pulley.) Performance engineers attack it from every angle. `" - "`Performance engineering is really about asking the right questions at the right time. `" - [[Performance testing to performance engineering]] - -