[mewpmewp2]

You would need a very perfect and flexible CI system in place that wouldn't need to rebuild anything it doesn't need and only run the tests you want or only recently failed tests etc.

Many CI systems would spin up a new box instead of using persistent so likely have to rebuild if no cache, etc.

So basically I would say most of the overhead is in not having a persistent box with knowledge of last build or ability to choose what to run in there, which pretty much just equals to local capabilities.

[peanball]

Often you also have the CI system designed in a way to verify a “from scratch” build that avoids any issues with “works on my machine” scenarios due to things still being cached that shouldn’t be there anymore.

[jayd16]

Having persistent boxes with sticky sessions seems seems pretty achievable.