docker 20.10.10 / cgroups v1 / fakeroot 1.31 / archlinux

$ docker run --rm -it archlinux sh
sh-5.1# pacman -Syu fakeroot
sh-5.1# time fakeroot whoami
root

real    0m0.019s
user    0m0.020s
sys     0m0.006s
sh-5.1# time fakeroot sh -c whoami
root

real    1m31.889s
user    0m26.470s
sys     1m5.309s
sh-5.1# fakeroot -v
fakeroot version 1.31