$ systemd-analyze
$ systemd-analyze time

Shows the overall time taken to boot the system, including the kernel, initrd, and userspace.

$ systemd-analyze blame
$ systemd-analyze plot > boot.svg

This command shows a list of all running units, ordered by the time they took to initialize.

$ systemd-analyze critical-chain
$ systemd-analyze critical-chain nginx.service

This command shows the time-critical chain of units, displaying the time each unit took to start and its dependencies.