Profile-guided optimization (PGO) is a compiler feature that leverages runtime profiling data to enhance the performance of Go applications by optimizing code through inlining and devirtualization. Now fully integrated into Go 1.21, PGO can be significantly enhanced using Grafana Pyroscope, an open-source continuous profiling database. Inlining involves replacing function calls with their bodies to eliminate overhead, while devirtualization optimizes interface calls into direct function calls, both improving execution efficiency based on real usage patterns. To utilize PGO with Pyroscope, developers can build an initial Go binary with profiling enabled, collect runtime profiles, query for optimal PGO data using Pyroscope's profilecli tool, and apply the PGO file during the build process. Real-world applications have shown performance improvements of 2-7% using PGO, with the potential for further gains as future versions of Go incorporate additional optimizations. This process can be implemented with Grafana Pyroscope or Grafana Cloud Profiles, providing valuable performance enhancements with minimal downsides.