Reviewed on: 2022-01-10

early_boot_instrumentation exists to collect and expose all coverage information from processes that exist before or outside the component framework. Such processes consist and are not limited to: - Physboot - Kernel - Boot Service


To add this project to your build, append --with //src/sys/early_boot_coverage to the fx set invocation.


early_boot_instrumentation groups the profile data in two groups, a static and a dynamic one. Static profile data refers to data that is not being updated while dynamic profile data is constantly changing. This is the result of processes who have exited versus those that are continuously running. For example a boot loader might expose static profile data, while the kernel exposes dynamic profile data.

Data is exposed in the form of VMO Files in two directories offered to this component's parent, ‘prof-data/static’ and ‘prof-data/dynamic’.