Compiling Shell Commands with CGO_ENABLED=0: A Performance Bottleneck

When utilizing network operations in Go programs, the compilation process can experience a significant slowdown with CGO_ENABLED=0. This behavior is observed even in minimalistic programs such as a basic HTTP server, where compilation without CGO_ENABLED=0 takes roughly nine times longer than with it enabled.

Root Cause of the Slowdown

The cause of this slowdown lies in the fact that standard library packages are pre-built without custom flags. When CGO_ENABLED is set to 0, the build flags change. As a result, the pre-built packages cannot be utilized, leading to the re-compilation of the majority of the standard library. This process is significantly more time-consuming than using the pre-built packages.

Mitigating the Slowdown

To mitigate this slowdown, the go build -i flag can be used. This flag installs packages that have been built with the modified flags. However, this solution has limited effectiveness because it speeds up subsequent builds with CGO_ENABLED=0 while slowing down builds without it.

A more efficient approach involves using the -installsuffix and -pkgdir flags to specify custom directories for installing packages built with different flags. This allows for fast compilation of Go programs with varying flags. In environments with multiple compilation modes, each mode can have its own designated directory, ensuring efficient compilation for all scenarios.