Felix Geisendörfer introduces a tool for continuous profile-guided optimization (PGO) for Go, designed to reduce CPU usage by up to 14% in Go services. The tool, datadog-pgo, integrates with the Go build process by using representative CPU profiles from production environments to optimize machine code, particularly in inlining and devirtualization of function calls. Testing on Datadog's internal services demonstrated significant CPU usage reduction, translating to substantial cost savings, even in already optimized services. Despite challenges such as a discovered memory usage increase due to an inlining issue in a gRPC library, Datadog implemented a mitigation and proposed a new goroutine stack profiler to the Go project. The tool, available for a free trial, promises further optimizations as Go's PGO capabilities evolve, with plans for wider deployment and more detailed results from Datadog's fleet-wide rollout.