Console hesitation on systemctl

tnmears · 2024-07-21 20:58:46

I noticed that when in the chroot on the install iso running systemctl like

systemctl enable whatever

runs instantly.

However, after logging into the new system, in a tty before installing anything graphical and after installing nvidia+xfce, when running the exact same command there is a noticeable delay. Both using sudo and as root.

is this normal?

I am using the July iso.

seth · 2024-07-22 07:19:01

How long is "a noticeable delay" in seconds?
Is *only* that command affected? disabling services or non-ystemctl stuff "echo foo" return instantly?

tnmears · 2024-07-22 15:06:35

Maybe a quarter of a second?

It also does it with disabling with systemctl. other commands don't seem affected.

cryptearth · 2024-07-22 16:23:57

so you feel 0.25s as "noticeable long"? my personal reaction time is slower than this - I wouldn't even be able to tell a difference

Trilby · 2024-07-22 16:48:59

A quarter second is pretty trivial. Enabling and disabling both trigger filesystem operations which would explain why it would be faster in the iso.

Head_on_a_Stick · 2024-07-22 17:00:52

The enable option just creates symlinks so do you see the same delay if you do that yourself?

For example, with nftables.service, instead of `systemctl enable` use

# ls -s /usr/lib/systemd/system/nftables.service /etc/systemd/system/multi-user.target.wants

Is that faster?

Disabling is just a matter of deleting the symlink, which should also be very quick.

Trilby · 2024-07-22 17:18:06

Head_on_a_Stick (emphasis added) wrote:

The enable option just creates symlinks

Are you sure that's all it does? It doesn't flush the write and / or confirm the link is properly in place?

Head_on_a_Stick · 2024-07-22 17:38:41

Yes, journal operations are also part of systemctl. My suggestion is intended to test if the symlinks are the problem or systemctl itself.

seth · 2024-07-22 18:26:03

Next to FS operations it could also be noise on the system bus (the reason we cannot just throw strace at the situation and look why systemd is slow) but at 250ms we should maybe actually measure the delay

sudo -v
time sudo systemctl enable whatever

and try that a couple of times to check whether it's consistent.

Speaking of: are subsequent (idempotent) calls slow as well?
Are --dry-run ones?

systemd takes a moment to enable a service here and my gut feeling is that the daemon reloads as consequence.

Arch Linux

#1 2024-07-21 20:58:46

Console hesitation on systemctl

#2 2024-07-22 07:19:01

Re: Console hesitation on systemctl

#3 2024-07-22 15:06:35

Re: Console hesitation on systemctl

#4 2024-07-22 16:23:57

Re: Console hesitation on systemctl

#5 2024-07-22 16:48:59

Re: Console hesitation on systemctl

#6 2024-07-22 17:00:52

Re: Console hesitation on systemctl

#7 2024-07-22 17:18:06

Re: Console hesitation on systemctl

#8 2024-07-22 17:38:41

Re: Console hesitation on systemctl

#9 2024-07-22 18:26:03

Re: Console hesitation on systemctl

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