How to decrease the boot time

If this system is not a server in a network, you can start by cutting down on time used by NetworkManager-wait-online.service, to do this please disable the service like so:

sudo systemctl disable NetworkManager-wait-online.service

If it shows up again after reboot, you can follow the above command with this:

sudo systemctl mask NetworkManager-wait-online.service

Pleas, try this first and check if your boot time improves before carrying on with any further steps. This alone, sometimes, reduces your boot time by a great deal.

To roll back the above changes anytime, please run:

sudo systemctl unmask NetworkManager-wait-online.service

Then follow it by:

sudo systemctl enable NetworkManager-wait-online.service

What is systemd-networkd-wait-online.service?

NAME systemd-networkd-wait-online.service, systemd-networkd-wait-online - Wait for network to come online

SYNOPSIS systemd-networkd-wait-online.service

   /lib/systemd/systemd-networkd-wait-online

DESCRIPTION systemd-networkd-wait-online is a oneshot system service (see systemd.service(5)), that waits for the network to be configured. By default, it will wait for all links it is aware of and which are managed by systemd- networkd.service(8) to be fully configured or failed, and for at least one link to be online. Here, online means that the link's operational state is equal or higher than "degraded". The threshold can be configured by --operational-state= option.

The purpose of the NetworkManager-wait-online.service is to wait for the network to come online before proceeding with the boot process.

This is needed in case of for example servers that rely on network resources as part of the boot process ( eg. mounting remote drives ) or in the case of workstations that rely on the network to boot correctly ( eg. Thin Clients ).

Otherwise, desktop users can disable NetworkManager-wait-online.service and network will connect normally after boot has finished minus the unneeded wait time.

It is safe to disable in this case.

This line with 1.5 seconds is a bug:

      1.552s systemd-backlight@backlight:intel_backlight.service

On my system without bug it is only 1 millisecond:

$ systemd-analyze blame | grep backlight

         1ms systemd-backlight@backlight:intel_backlight.service

More tips (including NetworkManager-wait-online.service) can be found here:

• How to speed up boot time on lubuntu