Distributed Systems Infrastructure (DSI) is MongoDB's framework for running fully automated system performance tests in our Continuous Integration (CI) environment. To run in CI it needs to automate everything end-to-end: provisioning and deploying multi-node clusters, executing tests, tuning the system for repeatable results, and collecting and analyzing the results. Today DSI is MongoDB's most used and most useful performance testing tool. It runs almost 200 different benchmarks in daily CI, and we also use it for manual performance investigations. As we can alert the responsible engineer in a timely fashion, all but one of the major regressions were fixed before the 4.2.0 release. We are also able to catch net new improvements, of which DSI caught 17. We open sourced DSI in March 2020.