portage-ng / portage / dev-ml / dune / 3.19.1
emerge -vp

These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 0.97 s (backtrack: 0/20).

[ebuild  N     ] dev-lang/ocaml-5.5.1:0/5.5.1::gentoo  USE="ocamlopt -emacs -flambda -latex -test -xemacs" 6457 KiB
[ebuild  N     ] dev-ml/dune-3.19.1:0/3.19.1::gentoo  USE="-emacs" 2850 KiB

Total: 2 packages (2 new), Size of downloads: 9306 KiB

Wall time
1.939 s vs. 0.011 s for portage-ng