ARM runners are supposed to be more energy efficient than x86. Also,
from limited testing, they appear to be faster for the eval jobs as
well. Average run time for the "Outpaths (x86_64-linux)" job was 4m 27s,
so far. In the first run, this job came in at 3m 9s. This effect did not
show for other jobs, yet.
The following two exceptions are made right now:
- nixpkgs-lib-tests currently fails on the ARM runner building Nix 2.3
- nixpkgs-vet is currently pinned to a x86_64-linux only binary release
This introduces some basic concepts used in these workflows and a common
terminology.
At the same time we remove some of the comments from various workflow
files, because they are assumed to be "general knowledge" through the
README.
Same top-level ordering of keys / empty lines and same indentation for
yaml lists. One blank line between each step.
Makes it easier to read and compare the workflows.
