The way things are computed is quite expensive, for some reason. No idea what the root cause is.

As a reference, a simple from alpine; echo hello world used to take about 700ms and 30% CPU on the old runtime, whereas it's roughly 3-4 seconds and 176% CPU on dagger.

# BLR
bl-runtime apply -s main  0.10s user 0.04s system 23% cpu 0.634 total

# Dagger
DOCKER_OUTPUT=1 DEBUG=1 dagger compute .  6.57s user 0.36s system 176% cpu 3.918 total

The CPU spike seems to indicate there's heavy Cue computation involved, which might cause the slowdown. Possible reason for this is how Dagger matches specifications (e.g. #Exec), by using Fill() + Validate().