This is a Python script for testing CMake glob overhead on an N file flat directory. It does the following:

1. Creates a CMake project with N sources, explicitly listed
2. Builds that project
3. Runs a no-op build on that project, records time spent
4. Repeats the above steps with a CONFIGURE_DEPENDS glob in place of the explicit list
5. Reports the difference

usage: test-glob.py [-h] [--generator GEN] [--source SOURCE] [--build BUILD] [-n N]

Test CMake glob performance

optional arguments:
  -h, --help       show this help message and exit
  --generator GEN  the CMake generator to use (e.g. Ninja)
  --source SOURCE  directory in which to place the test case
  --build BUILD    directory in which to build the test case
  -n N             number of files to create

See the GitHub Actions logs for some performance numbers. Below is a table with some experiments I ran locally.

Open a PR with your own tests and reports if you'd like to add them to the table!