[systemd-devel] Grouping services in systemd..

[Reindl Harald]

Am 02.04.20 um 15:21 schrieb nitish nagesh:
>   We are working on an embedded ARM Cortex A9 based system (aka low
> CPU). It runs on a custom linux based operating system which uses systemd.
> 
>   We have a bunch of daemons (around ~50+) that come up during boot
> simultaneously which slows down the boot significantly as the CPU runs
> out of breath. We were thinking of staggering these daemons into 2
> groups. The first group containing "critical" daemons (around 15) so
> that they finish faster and make the system usable sooner. Followed by
> the second group of daemons.
> 
>    Separating daemons into buckets could be done using: 
> 1) systemd targets: Introduce 2 new targets and classify the
> services/daemons into them. Layer these targets during boot.
> 2) Cgroups: Create a new systemd slice and put all the "critical"
> services into it. Allocate sufficient CPUShares value to the slice so
> that this slice gets its due CPU% to finish faster boot.
> 
> Can you please suggest which of the above is a better approach?
> Respective pros/cons with each.
> 
> Or if there is a third approach better than the above?

with proper After/Before ordering should work too

don't apply for "Type=simple" and in that case targets won't help either
because every "simple" service prevent waiting for something

in the end i doubt slowing things down would solve anything! when stuff
is needed it's needed and if not make it socket activated instead fire
everything up at boot