[kylegalbraith]

Yup! We observed the same thing back before we built Depot. The act of saving/loading cache over a GHA network pretty much negated any performance gain from layer caching. So, we created a solution to persist cache to NVMe disks and orchestrate that across builds so it's immediately available on the next build. All the performance of layer caching without any network transfer.

The registry cache idea is a neat idea, but in practice suffers the same problem.

[notnmeyer]

totally, your approach is the right one and anything reasonable is going to focus on collocating the cache as close as possible to where the build runs.