A 45-minute CI pipeline is a tax on every engineer every day. If your team runs 50 builds per day and each build takes 45 minutes instead of 12 minutes, that is 27.5 hours of wall-clock time lost daily, plus the context-switching cost of engineers waiting for CI before they can merge and move to the next task. CI pipeline performance is engineering leverage, and most teams leave significant time on the table.
"CI pipeline speed is a proxy for how seriously an engineering organization takes developer experience. Every minute of unnecessary CI wait time is a minute of context switching, a minute of multitasking, a minute of reduced flow state. The cumulative cost is measured in engineering productivity, not pipeline minutes."
— Nicole Forsgren, PhD, VP of Research and Strategy, GitHub, co-author of Accelerate (2023)## Parallelization: the highest-leverage intervention
If your pipeline runs tests sequentially, fixing that is the highest-leverage change you can make. Most test suites can be split across multiple runners with 80 to 90 percent efficiency. A test suite that takes 30 minutes on one runner might take 5 minutes across eight runners, with the remaining time being setup overhead rather than test execution.
