portage-ng / portage / sys-kernel / linux-headers / 4.14-r2
emerge -vp

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

Calculating dependencies ... done!
Dependency resolution took 1.49 s (backtrack: 0/20).

[ebuild     UD ] sys-kernel/linux-headers-4.14-r2::gentoo [6.19::gentoo] USE="-headers-only" 7835 KiB

Total: 1 package (1 downgrade), Size of downloads: 7835 KiB

Wall time
2.480 s vs. 0.004 s for portage-ng